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Taylor AL, Bonventre JV, Uliasz TF, Hewett JA, Hewett SJ. Cytosolic phospholipase A2 alpha inhibition prevents neuronal NMDA receptor-stimulated arachidonic acid mobilization and prostaglandin production but not subsequent cell death. J Neurochem 2008; 106:1828-40. [PMID: 18564366 PMCID: PMC2582587 DOI: 10.1111/j.1471-4159.2008.05527.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phospholipase A(2) (PLA(2)) enzymes encompass a superfamily of at least 13 extracellular and intracellular esterases that hydrolyze the sn-2 fatty acyl bonds of phospholipids to yield fatty acids and lysophospholipids. The purpose of this study was to characterize which phospholipase paralog regulates NMDA receptor-mediated arachidonic acid (AA) release. Using mixed cortical cell cultures containing both neurons and astrocytes, we found that [(3)H]-AA released into the extracellular medium following NMDA receptor stimulation (100 microM) increased with time and was completely prevented by the addition of the NMDA receptor antagonist MK-801 (10 microM) or by removal of extracellular Ca(2+). Neither diacylglycerol lipase inhibition (RHC-80267; 10 microM) nor selective inhibition of Ca(2+)-independent PLA(2) [bromoenol lactone (BEL); 10 microM] alone had an effect on NMDA receptor-stimulated release of [(3)H]-AA. Release was prevented by methyl arachidonyl fluorophosphonate (MAFP) (5 microM) and AACOCF(3) (1 microM), inhibitors of both cytosolic PLA(2) (cPLA(2)) and Ca(2+)-independent PLA(2) isozymes. This inhibition effectively translated to block of NMDA-induced prostaglandin (PG) production. An inhibitor of p38MAPK, SB 203580 (7.5 microM), also significantly reduced NMDA-induced PG production providing suggestive evidence for the role of cPLA(2)alpha. Its involvement in release was confirmed using cultures derived from mice deficient in cPLA(2)alpha, which failed to produce PGs in response to NMDA receptor stimulation. Interestingly, neither MAFP, AACOCF(3) nor cultures derived from cPLA(2)alpha null mutant animals showed any protection against NMDA-mediated neurotoxicity, indicating that inhibition of this enzyme may not be a viable protective strategy in disorders of the cortex involving over-activation of the NMDA receptor.
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Affiliation(s)
- Ava L Taylor
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA
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102
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Siddiqui RA, Harvey KA, Zaloga GP. Modulation of enzymatic activities by n-3 polyunsaturated fatty acids to support cardiovascular health. J Nutr Biochem 2008; 19:417-37. [PMID: 17904342 DOI: 10.1016/j.jnutbio.2007.07.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 06/14/2007] [Accepted: 07/03/2007] [Indexed: 12/13/2022]
Abstract
Epidemiological evidence from Greenland Eskimos and Japanese fishing villages suggests that eating fish oil and marine animals can prevent coronary heart disease. Dietary studies from various laboratories have similarly indicated that regular fish oil intake affects several humoral and cellular factors involved in atherogenesis and may prevent atherosclerosis, arrhythmia, thrombosis, cardiac hypertrophy and sudden cardiac death. The beneficial effects of fish oil are attributed to their n-3 polyunsaturated fatty acid (PUFA; also known as omega-3 fatty acids) content, particularly eicosapentaenoic acid (EPA; 20:5, n-3) and docosahexaenoic acid (DHA; 22:6, n-3). Dietary supplementation of DHA and EPA influences the fatty acid composition of plasma phospholipids that, in turn, may affect cardiac cell functions in vivo. Recent studies have demonstrated that long-chain omega-3 fatty acids may exert beneficial effects by affecting a wide variety of cellular signaling mechanisms. Pathways involved in calcium homeostasis in the heart may be of particular importance. L-type calcium channels, the Na+-Ca2+ exchanger and mobilization of calcium from intracellular stores are the most obvious key signaling pathways affecting the cardiovascular system; however, recent studies now suggest that other signaling pathways involving activation of phospholipases, synthesis of eicosanoids, regulation of receptor-associated enzymes and protein kinases also play very important roles in mediating n-3 PUFA effects on cardiovascular health. This review is therefore focused on the molecular targets and signaling pathways that are regulated by n-3 PUFAs in relation to their cardioprotective effects.
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Affiliation(s)
- Rafat A Siddiqui
- Cellular Biochemistry Laboratory, Methodist Research Institute, Clarian Health, Indianapolis, IN 46202, USA.
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103
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Titsworth WL, Liu NK, Xu XM. Role of secretory phospholipase a(2) in CNS inflammation: implications in traumatic spinal cord injury. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2008; 7:254-69. [PMID: 18673210 PMCID: PMC2800081 DOI: 10.2174/187152708784936671] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are a subfamily of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor (PAF). The hydrolysis of membrane phospholipids by PLA(2) is a rate-limiting step for generation of eicosanoids and PAF. To date, more than 10 isozymes of sPLA(2) have been found in the mammalian central nervous system (CNS). Under physiological conditions, sPLA(2)s are involved in diverse cellular responses, including host defense, phospholipid digestion and metabolism. However, under pathological situations, increased sPLA(2) activity and excessive production of free fatty acids and their metabolites may lead to inflammation, loss of membrane integrity, oxidative stress, and subsequent tissue injury. Emerging evidence suggests that sPLA(2) plays a role in the secondary injury process after traumatic or ischemic injuries in the brain and spinal cord. Importantly, sPLA(2) may act as a convergence molecule that mediates multiple key mechanisms involved in the secondary injury since it can be induced by multiple toxic factors such as inflammatory cytokines, free radicals, and excitatory amino acids, and its activation and metabolites can exacerbate the secondary injury. Blocking sPLA(2) action may represent a novel and efficient strategy to block multiple injury pathways associated with the CNS secondary injury. This review outlines the current knowledge of sPLA(2) in the CNS with emphasis placed on the possible roles of sPLA(2) in mediating CNS injuries, particularly the traumatic and ischemic injuries in the brain and spinal cord.
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Affiliation(s)
- W. Lee Titsworth
- Kentucky Spinal Cord Injury Research Center, Departments of Neurological Surgery, and Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Nai-Kui Liu
- Kentucky Spinal Cord Injury Research Center, Departments of Neurological Surgery, and Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute and Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Xiao-Ming Xu
- Kentucky Spinal Cord Injury Research Center, Departments of Neurological Surgery, and Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute and Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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104
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Boutrin MCF, Foster HA, Pentreath VW. The effects of bee (Apis mellifera) venom phospholipase A2 on Trypanosoma brucei brucei and enterobacteria. Exp Parasitol 2008; 119:246-51. [PMID: 18343372 DOI: 10.1016/j.exppara.2008.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 01/31/2008] [Accepted: 02/01/2008] [Indexed: 11/29/2022]
Abstract
The potential role of phospholipases in trypanosomiasis was investigated using bee venom phospholipase A2 (bvPLA2) as a model. The effects of bvPLA2 on the survival of Trypanosoma brucei brucei, 2h and 12h cultures of Enterobacter cloacae, Escherichia coli, Citrobacter freundii were studied. About 1 mg ml(-1) bvPLA2 was trypanocidal after 30 min. Some growth occurred at lower concentrations up to 2h after treatment but viability decreased up to 8h. Even very low concentrations of bvPLA2 (10(-12) mg ml(-1)) had some trypanocidal activity. Bee venom PLA2 was bactericidal to 2h bacterial cultures but bacteriostatic to 12h ones. Minimum bactericidal concentrations were 10(-5)-10(-6) mg ml(-1). The results showed that bvPLA2 had significant trypanocidal and antibacterial effects on Gram-negative bacteria. The relationship to events occurring during infection is discussed. Phospholipases may play a role in increased endotoxin levels in trypanosomiasis.
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Affiliation(s)
- M-C F Boutrin
- Centre for Parasitology and Infectious Diseases, Biomedical Sciences Research Institute, School of Environment and Life Sciences, University of Salford, The Crescent Salford, Lancs M5 4WT, United Kingdom
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105
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Abstract
Formation of liquid-ordered domains in model membranes can be linked to raft formation in cellular membranes. The lipid stoichiometry has a governing influence on domain formation and consequently, biochemical hydrolysis of specific lipids has the potential to remodel domain features. Activation of phospholipase A(2) (PLA(2)) by ternary model membranes with three components (DOPC/DPPC/Cholesterol) can potentially change the domain structure by preferential hydrolysis of the phospholipids. Using fluorescence microscopy, this work investigates the changes in domain features that occur upon PLA(2) activation by such ternary membranes. Double-supported membranes are used, which have minimal interactions with the solid support. For membranes prepared in the coexistence region, PLA(2) induces a decrease of the liquid-disordered (L(d)) phase and an increase of the liquid-ordered (L(o)) phase. A striking observation is that activation by a uniform membrane in the L(d) phase leads to nucleation and growth of L(o)-like domains. This phenomenon relies on the initial presence of cholesterol and no PLA(2) activation is observed by membranes purely in the L(o) phase. The observations can be rationalized by mapping partially hydrolyzed islands onto trajectories in the phase diagram. It is proposed that DPPC is protected from hydrolysis through interactions with cholesterol, and possibly the formation of condensed complexes. This leads to specific trajectories which can account for the observed trends. The results demonstrate that PLA(2) activation by ternary membrane islands may change the global lipid composition and remodel domain features while preserving the overall membrane integrity.
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106
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Han R, Chen B, Smith TJ. Jak2 dampens the induction by IL-1beta of prostaglandin endoperoxide H synthase 2 expression in human orbital fibroblasts: evidence for divergent influence on the prostaglandin E2 biosynthetic pathway. THE JOURNAL OF IMMUNOLOGY 2007; 179:7147-56. [PMID: 17982107 DOI: 10.4049/jimmunol.179.10.7147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Prostaglandin endoperoxide H synthase 2 (PGHS-2) catalyzes the rate-limiting steps in the synthesis of PGE(2). It is substantially but transiently induced in human orbital fibroblasts treated with IL-1beta. In this study, we report that the induction of PGHS-2 by IL-1beta is dramatically enhanced and prolonged when Jak2 signaling is abrogated, either with the specific inhibitor AG490 or by transiently transfecting fibroblasts with a dominant negative mutant Jak2. Attenuating Jak2 increases PGHS-2 steady-state mRNA levels, a consequence of increased gene transcription and mRNA survival in IL-1beta-treated cultures. Surprisingly, interrupting Jak2 function also blocked the expected increase in PGE(2) synthesis usually provoked by IL-1beta. This resulted from the rapid loss of IL-1beta-dependent arachidonate release and by attenuation of group IIA secreted PLA(2) (sPLA(2)) gene induction. Supplying Jak2-compromised cultures with exogenous arachidonate failed to increase PGE(2) production in response to IL-1beta until cells were mechanically disrupted. However, transiently transfecting them with wild-type sPLA(2) fully restored prostanoid production to anticipated levels. sPLA(2) expression following transfection resulted in increased IL-1beta-dependent PGHS-2 and microsomal PGE(2) synthase levels. Thus, sPLA(2) plays important roles in PGE(2) synthesis in addition to its release of arachidonate. Our findings suggest that Jak2 ordinarily dampens and limits the duration of the PGHS-2 induction by IL-1beta. Moreover, it is required for IL-1beta-dependent signaling to sPLA(2), the expression and activity of which are necessary for up-regulating PGE(2) synthesis in orbital fibroblasts.
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Affiliation(s)
- Rui Han
- Department of Medicine, Division of Molecular Medicine, Harbor-University of California Los Angeles Medical Center, Torrance, CA 90502, USA
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107
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de Godoy MAF, Rattan S. Role of phospholipase A2 (group I secreted) in the genesis of basal tone in the internal anal sphincter smooth muscle. Am J Physiol Gastrointest Liver Physiol 2007; 293:G979-86. [PMID: 17717042 DOI: 10.1152/ajpgi.00310.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role of phospholipase A(2) (PLA(2)) in the genesis of basal tone in the internal anal sphincter (IAS) is not known. We determined the effects of PLA(2) and inhibitors on the basal tone and intraluminal pressures (IASP) in the rat IAS vs. rectal smooth muscles (RSM). In addition, we determined the correlations between the IAS tone, PLA(2) levels, and the actual enzymatic activity. Inhibition of PLA(2) by 4-bromophenacyl bromide (universal inhibitor of PLA(2)) and MJ33 [selective inhibitor of secreted isoform of PLA(2) (sPLA(2))] caused concentration-dependent decrease in the IAS tone and in the IASP. Maximal decreases in the IAS tone and IASP by 4-bromophenacyl bromide and MJ33 were 58.8 +/- 6.9 and 51.5 +/- 6.3%, and 66.7 +/- 5.1 and 79.8 +/- 8.2%, respectively. The sPLA(2) inhibitors were approximately 100 times more potent in decreasing the IASP than the mean blood pressure. Conversely, the selective inhibitors of the cytosolic and calcium-independent PLA(2) arachidonyl trifluoromethyl ketone and bromoenol lactone, respectively, produced no significant effect. The IAS had characteristically higher levels of sPLA(2) activity (26.5 +/- 4.9 micromol.min(-1).ml(-1)) vs. the RSM (3.2 +/- 0.4 micromol.min(-1).ml(-1)), and higher levels of sPLA(2) as shown by Western blot and RT-PCR. Interestingly, administration of sPLA(2) transformed RSM into the tonic smooth muscle like that of the IAS: it developed basal tone and relaxed in response to the electrical field stimulation. From the present data, we conclude that sPLA(2) plays a critical role in the genesis of tone in the IAS. PLA(2) inhibitors may provide potential therapeutic target for treating anorectal motility disorders.
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Affiliation(s)
- Márcio A F de Godoy
- Department of Medicine, Division of Gastroenterology and Hepatology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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108
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Markert Y, Mansfeld J, Schierhorn A, Rücknagel KP, Ulbrich-Hofmann R. Production of synthetically created phospholipase A(2) variants with industrial impact. Biotechnol Bioeng 2007; 98:48-59. [PMID: 17318911 DOI: 10.1002/bit.21392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phospholipases A(2) (PLA(2)) play an important role for the production of lysophospholipids. Presently they are mainly obtained from porcine or bovine pancreas but these mammalian sources are not accepted in several fields of application. To make accessible a non-mammalian PLA(2) to industrial application, synthetic genes encoding PLA(2) from honey bee (Apis mellifera) with modified N-termini were constructed and expressed in Escherichia coli. While expression of the gene with an N-terminal leader sequence to direct the protein into the periplasm failed, four variants with slightly modified N-termini (I1A-PLA(2), I1V-PLA(2), His(6)-tagged PLA(2) and PLA(2) still containing the start methionine) were successfully expressed. In all cases, the PLA(2) variants were produced as inclusion bodies. Their protein content amounted to 26-35% of total cell protein. The optimized renaturation procedure and subsequent purification by cation-exchange chromatography yielded pure active enzymes in yields of 4-11 mg L(-1). The recombinant PLA(2) variants showed activities, far-UV CD and fluorescence spectra similar to the glycosylated PLA(2) isolated from the venom glands of honey bee (bv-PLA(2)). The thermodynamic stabilities of the recombinant enzymes calculated from the transition curves of guanidine hydrochloride induced unfolding were also nearly identical to the stability of bv-PLA(2). For the variant I1A-PLA(2) high-cell density fermentation in 10 L-scale using mineral salt medium was shown to increase the volumetric enzyme yield considerably.
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Affiliation(s)
- Yvonne Markert
- Institute of Biochemistry and Biotechnology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes Strasse 3, 06120 Halle, Germany
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109
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110
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Linderoth L, Andresen TL, Jørgensen K, Madsen R, Peters GH. Molecular basis of phospholipase A2 activity toward phospholipids with sn-1 substitutions. Biophys J 2007; 94:14-26. [PMID: 17827229 PMCID: PMC2134884 DOI: 10.1529/biophysj.107.110106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We studied secretory phospholipase A(2) type IIA (sPLA(2)) activity toward phospholipids that are derivatized in the sn-1 position of the glycerol backbone. We explored what type of side group (small versus bulky groups, hydrophobic versus polar groups) can be introduced at the sn-1 position of the glycerol backbone of glycerophospholipids and at the same time be hydrolyzed by sPLA(2). The biophysical characterization revealed that the modified phospholipids can form multilamellar vesicles, and several of the synthesized sn-1 functionalized phospholipids were hydrolyzed by sPLA(2). Molecular dynamics simulations provided detailed insight on an atomic level that can explain the observed sPLA(2) activity toward the different phospholipid analogs. The simulations revealed that, depending on the nature of the side chain located at the sn-1 position, the group may interfere with an incoming water molecule that acts as the nucleophile in the enzymatic reaction. The simulation results are in agreement with the experimentally observed sPLA(2) activity toward the different phospholipid analogs.
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Affiliation(s)
- Lars Linderoth
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby, Denmark
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111
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Mori T, Ito S, Namiki M, Suzuki T, Kobayashi S, Matsubayashi K, Sawaguchi T. Involvement of free radicals followed by the activation of phospholipase A2 in the mechanism that underlies the combined effects of methamphetamine and morphine on subacute toxicity or lethality in mice: Comparison of the therapeutic potential of fullerene, mepacrine, and cooling. Toxicology 2007; 236:149-57. [PMID: 17553606 DOI: 10.1016/j.tox.2007.03.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 03/25/2007] [Accepted: 03/28/2007] [Indexed: 11/28/2022]
Abstract
An increase in polydrug abuse is a major problem worldwide. The coadministration of methamphetamine and morphine increased subacute toxicity or lethality in rodents. However, the underlying mechanisms by which lethality is increased by the coadministration of methamphetamine and morphine are not yet fully understood. Coadministered methamphetamine and morphine induced lethality by more than 80% in BALB/c mice, accompanied by the rupture of cells in the kidney and liver, and an increase in poly (ADP-ribose) polymerase (PARP)-immunoreactive cells in the heart, kidney and liver. The lethal effect and the increase in the incidence of rupture or PARP-immunoreactive cells induced by the coadministration of methamphetamine and morphine was significantly attenuated by pretreatment with mepacrine (phospholipase A(2) inhibitor) or fullerene (a radical scavenger), or by cooling from 30 to 90 min after drug administration. Furthermore, based on the results of the electron spin resonance spin-trapping technique, hydroxyl radicals were increased by the administration of methamphetamine and morphine, and these increased hydroxyl radicals were potently attenuated by fullerene and cooling. These results suggest that hydroxyl radicals plays an important role in the increased lethality induced by the coadministration of methamphetamine plus morphine. The potency of cooling or drugs for decreasing the subacute toxicity or lethality induced by the coadministration of methamphetamine and morphine was in the order fullerene=cooling>mepacrine. These results indicate that fullerene and cooling are beneficial for preventing death that is induced by the coadministration of methamphetamine and morphine.
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Affiliation(s)
- Tomohisa Mori
- Department of Legal Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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112
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Sun GY, Horrocks LA, Farooqui AA. The roles of NADPH oxidase and phospholipases A2 in oxidative and inflammatory responses in neurodegenerative diseases. J Neurochem 2007; 103:1-16. [PMID: 17561938 DOI: 10.1111/j.1471-4159.2007.04670.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Reactive oxygen species (ROS) are produced in mammalian cells through enzymic and non-enzymic mechanisms. Although some ROS production pathways are needed for specific physiological functions, excessive production is detrimental and is regarded as the basis of numerous neurodegenerative diseases. Among enzymes producing superoxide anions, NADPH oxidase is widespread in mammalian cells and is an important source of ROS in mediating physiological and pathological processes in the cardiovascular and the CNS. ROS production is linked to the alteration of intracellular calcium homeostasis, activation of Ca(2+)-dependent enzymes, alteration of cytoskeletal proteins, and degradation of membrane glycerophospholipids. There is evolving evidence that ROS produced by NADPH oxidase regulate neuronal functions and degrade membrane phospholipids through activation of phospholipases A(2) (PLA(2)). This review is intended to cover recent studies describing ROS generation from NADPH oxidase in the CNS and its downstream activation of PLA(2), namely, the group IV cytosolic cPLA(2) and the group II secretory sPLA(2). A major focus is to elaborate the dual role of NADPH oxidase and PLA(2) in mediating the oxidative and inflammatory responses in neurodegenerative diseases, including cerebral ischemia and Alzheimer's disease. Elucidation of the signaling pathways linking NADPH oxidase with the multiple forms of PLA(2) will be important in understanding the oxidative and degradative mechanisms that underline neuronal damage and glial activation and will facilitate development of therapeutic intervention for prevention and treatment of these and other neurodegenerative diseases.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA.
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113
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Frasch SC, Zemski-Berry K, Murphy RC, Borregaard N, Henson PM, Bratton DL. Lysophospholipids of Different Classes Mobilize Neutrophil Secretory Vesicles and Induce Redundant Signaling through G2A. THE JOURNAL OF IMMUNOLOGY 2007; 178:6540-8. [PMID: 17475884 DOI: 10.4049/jimmunol.178.10.6540] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Lysophosphatidylcholine has been shown to enhance neutrophil functions through a mechanism involving the G protein-coupled receptor G2A. Recent data support an indirect effect of lysophosphatidylcholine on G2A rather than direct ligand binding. These observations prompted the hypothesis that other lysophospholipids (lyso-PLs) may also signal for human neutrophil activation through G2A. To this end, 1-oleoyl-2-hydroxy-sn-glycero-3-[phospho-L-choline], but also C18:1/OH lyso-PLs bearing the phosphoserine and phosphoethanolamine head groups, presented on albumin, were shown to signal for calcium flux in a self- and cross-desensitizing manner, implicating a single receptor. Blocking Abs to G2A inhibited calcium signaling by all three lyso-PLs. Furthermore, inhibition by both pertussis toxin and U-73122 established signaling via the Galphai/phospholipase C pathway for calcium mobilization. Altered plasma membrane localization of G2A has been hypothesized to facilitate signaling. Accordingly, an increase in detectable G2A was demonstrated by 1 min after lyso-PL stimulation and was followed by visible patching of the receptor. Western blotting showed that G2A resides in the plasma membrane/secretory vesicle fraction and not in neutrophil primary, secondary, or tertiary granules. Enhanced detection of G2A induced by lyso-PLs was paralleled by enhanced detection of CD45, confirming mobilization of the labile secretory vesicle pool. Together, these data show that lyso-PLs bearing various head groups redundantly mobilize G2A latent within secretory vesicles and result in G2A receptor/Galphai/phospholipase C signaling for calcium flux in neutrophils.
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Affiliation(s)
- S Courtney Frasch
- Department of Pediatrics, Division of Cell Biology, National Jewish Medical and Research Center, Denver, CO 80206, USA
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114
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Maurin T, Fenard D, Lambeau G, Doglio A. An Envelope-determined Endocytic Route of Viral Entry Allows HIV-1 to Escape from Secreted Phospholipase A2 Entry Blockade. J Mol Biol 2007; 367:702-14. [PMID: 17292399 DOI: 10.1016/j.jmb.2007.01.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 01/08/2007] [Indexed: 10/23/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)s) represent a new class of human immunodeficiency virus (HIV) inhibitors that block the early steps of virus entry into cells. Here, we applied an in vitro evolution/selection procedure to select, from primary HIV isolates, an emerging variant (HIV(RBV-3)) able to actively infect cells in the presence of sPLA(2)s. HIV(RBV-3) represents a very atypical HIV-1 isolate because, in contrast to others, this virus requires a functional endocytic machinery to infect cells. Indeed, endocytosis inhibitors that affect endosome acidification (bafilomycin A(1), monensin) and/or endosomal trafficking (nocodazole, latrunculin A) drastically reduced HIV(RBV-3) replication. Using a standardized PCR-assay, we showed that endocytosis inhibitors block HIV(RBV-3) entry just before the reverse transcription step. Concurrently, to identify the viral proteins responsible for the HIV(RBV-3) atypical behaviour, we constructed a HIV-1 molecular chimera bearing different HIV(RBV-3) proteins. We demonstrated that the sole presence of the HIV(RBV-3) envelope glycoprotein is enough, not only to confer the resistance to sPLA(2)s, but also to direct HIV(RBV-3) to the endosomal-dependent entry pathway. Interestingly, HIV(RBV-3) envelope glycoprotein sequencing revealed an unusual structural pattern with the presence of rare mutations in the N-terminal region and V1-V2 envelope loop sequence extensions. Taken together, we conclude that HIV-1 may escape from entry inhibitors, such as sPLA2s, through the selection of a particular HIV-1 envelope glycoprotein that allows HIV to infect cells via an alternative entry route that relies on endosome trafficking.
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Affiliation(s)
- Thomas Maurin
- Inserm U526, Laboratoire de Virologie, Faculté de Médecine, Avenue de Valombrose, 06107 Nice cedex 2, France
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115
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Solodkin-Szaingurten I, Levy R, Hadad N. Differential behavior of sPLA2-V and sPLA2-X in human neutrophils. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:155-63. [PMID: 17275398 DOI: 10.1016/j.bbalip.2006.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 11/30/2006] [Accepted: 11/30/2006] [Indexed: 11/29/2022]
Abstract
Neutrophils and differentiated PLB-985 cells contain various types of PLA(2)s including the 85 kDa cytosolic PLA(2) (cPLA(2)), Ca(2+)-independent PLA(2) (iPLA(2)) and secreted PLA(2)s (sPLA(2)s). The present study focuses on the behavior of sPLA(2)s in neutrophils and PLB cells and their relationship to cPLA(2)alpha. The results of the present research show that the two types of sPLA(2) present in neutrophils, sPLA(2)-V and sPLA(2)-X, which are located in the azurophil granules, are differentially affected by physiological stimuli. While sPLA(2)-V is secreted to the extacellular milieu, sPLA(2)-X is detected on the plasma membranes after stimulation. Stimulation of neutrophils with formyl-Met-Leu-Phe (fMLP), opsonized zymosan (OZ) or A23187 resulted in a different kinetics of sPLA(2) secretion as detected by its activity in the neutrophil supernatants. Neutrophil priming by inflammatory cytokines or LPS enhanced sPLA(2) activity detected in the supernatant after stimulation by fMLP. This increased activity was due to increased secretion of sPLA(2)-V to the supernatant and not to release of sPLA(2)-X. sPLA(2) in granulocyte-like PLB cells exhibit identical characteristics to neutrophil sPLA(2), with similar activity and optimal pH of 7.5. Granulocyte-like cPLA(2)alpha-deficient PLB cells serve as a good model to study whether sPLA(2) activity is regulated by cPLA(2)alpha. Secretion and activity of sPLA(2) were found to be similar in granulocyte-like PLB cells expressing or lacking cPLA(2)alpha, indicating that they are not under cPLA(2)alpha regulation.
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Affiliation(s)
- I Solodkin-Szaingurten
- Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, Beer Sheva 84105, Israel
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Singh DK, Gesquiere LR, Subbaiah PV. Role of sphingomyelin and ceramide in the regulation of the activity and fatty acid specificity of group V secretory phospholipase A2. Arch Biochem Biophys 2006; 459:280-7. [PMID: 17178097 PMCID: PMC1857358 DOI: 10.1016/j.abb.2006.11.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 11/16/2006] [Accepted: 11/16/2006] [Indexed: 01/23/2023]
Abstract
We previously showed that group V secretory phospholipase A(2) (sPLA(2)V) is inhibited by sphingomyelin (SM), but activated by ceramide. Here, we investigated the effect of sphingolipid structure on the activity and acyl specificity of sPLA(2)V. Degradation of HDL SM to ceramide, but not to ceramide phosphate, stimulated the activity by 6-fold, with the release of all unsaturated fatty acids being affected equally. Ceramide-enrichment of HDL similarly stimulated the release of unsaturated fatty acids. Incorporation of SM into phosphatidylcholine (PC) liposomes preferentially inhibited the hydrolysis of 16:0-20:4 PC. Conversely, SMase C treatment or ceramide incorporation resulted in preferential stimulation of hydrolysis of 16:0-20:4 PC. The presence of a long chain acyl group in ceramide was essential for the activation, and long chain diacylglycerols were also effective. However, ceramide phosphate was inhibitory. These studies show that SM and ceramide in the membranes and lipoproteins not only regulate the activity of phospholipases, but also the release of arachidonate, the precursor of eicosanoids.
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Affiliation(s)
| | | | - Papasani V. Subbaiah
- *Address correspondence to: P.V.Subbaiah, Ph.D., Section of Diabetes and Metabolism, University of Illinois at Chicago, 1819 West Polk, M/C 797, Chicago, IL 60612, Ph: 312-996-8212; FAX: 312-413-0437,
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Putz T, Ramoner R, Gander H, Rahm A, Bartsch G, Thurnher M. Antitumor action and immune activation through cooperation of bee venom secretory phospholipase A2 and phosphatidylinositol-(3,4)-bisphosphate. Cancer Immunol Immunother 2006; 55:1374-83. [PMID: 16485125 PMCID: PMC11030777 DOI: 10.1007/s00262-006-0143-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Accepted: 01/27/2006] [Indexed: 10/25/2022]
Abstract
We evaluated tumor cell growth modulation by bee venom secretory phospholipase A2 (bv-sPLA2) and phosphatidylinositol-(3,4)-bisphosphate as well as potential cooperative effects. In addition, the immunomodulatory impact of tumor cell treatment was examined by monitoring changes in phenotype and function of monocyte-derived dendritic cells (moDCs) cocultured with pretreated tumor cells. Bv-sPLA2 or phosphatidylinositol-(3,4)-bisphosphate alone displayed moderate effects on the proliferation of A498 renal cell carcinoma cells, T-47D breast cancer cells, DU145 prostate cancer cells and BEAS-2B transformed lung cells. However, when bv-sPLA2 was coadministered with phosphatidylinositol-(3,4)-bisphosphate a potent inhibition of [3H] thymidine incorporation into all tested cell lines occurred. This inhibition was due to massive cell lysis that reduced the number of cells with proliferative capacity. Importantly, tumor cell lysates generated with bv-sPLA2 plus phosphatidylinositol-(3,4)-bisphosphate induced maturation of human moDCs demonstrated by enhanced expression of CD83 and improved stimulation in allogeneic mixed leukocyte reactions. Our data demonstrate that bv-sPLA2 and phosphatidylinositol-(3,4)-bisphosphate synergistically generate tumor lysates which enhance the maturation of immunostimulatory human monocyte-derived dendritic cells. Such tumor lysates which represent complex mixtures of tumor antigens and simultaneously display potent adjuvant properties meet all requirements of a tumor vaccine.
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Affiliation(s)
- Thomas Putz
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Reinhold Ramoner
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Hubert Gander
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Andrea Rahm
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Georg Bartsch
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Martin Thurnher
- Department of Urology, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
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Dey I, Lejeune M, Chadee K. Prostaglandin E2 receptor distribution and function in the gastrointestinal tract. Br J Pharmacol 2006; 149:611-23. [PMID: 17016496 PMCID: PMC2014644 DOI: 10.1038/sj.bjp.0706923] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 07/11/2006] [Accepted: 08/29/2006] [Indexed: 12/24/2022] Open
Abstract
Prostaglandin E2 (PGE2) is one of the most important biologically active prostanoids found throughout the gastrointestinal tract. Despite the fact that PGE2 regulates many physiological functions of the gut including mucosal protection, gastrointestinal secretion and motility, it is implicated in the pathophysiology of inflammatory bowel diseases (IBD) and colorectal neoplasia. The varied biological functions exerted by PGE2 are through the pharmacologically distinct, G-protein coupled plasma membrane receptors termed EP receptors. Disruptions of various prostanoid receptor genes have helped in unravelling the physiological functions of these receptors. To date, all four subtypes of EP receptors have been individually knocked out in mice and various phenotypes have been reported for each subtype. Similarly, in vitro and in vivo studies using EP receptor agonists and antagonists have helped in uncoupling the diverse functions of PGE2 signalling involving distinct EP receptors in the gut. In this review, we will summarize and conceptualize the salient features of EP receptor subtypes, their regional functions in the gut and how expressions of EP receptors are altered during disease states.
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Affiliation(s)
- I Dey
- Department of Microbiology and Infectious Disease, Health Sciences Centre, University of Calgary Calgary, Alberta, Canada
| | - M Lejeune
- Department of Microbiology and Infectious Disease, Health Sciences Centre, University of Calgary Calgary, Alberta, Canada
| | - K Chadee
- Department of Microbiology and Infectious Disease, Health Sciences Centre, University of Calgary Calgary, Alberta, Canada
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Farooqui AA, Ong WY, Horrocks LA. Inhibitors of brain phospholipase A2 activity: their neuropharmacological effects and therapeutic importance for the treatment of neurologic disorders. Pharmacol Rev 2006; 58:591-620. [PMID: 16968951 DOI: 10.1124/pr.58.3.7] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The phospholipase A(2) family includes secretory phospholipase A(2), cytosolic phospholipase A(2), plasmalogen-selective phospholipase A(2), and calcium-independent phospholipase A(2). It is generally thought that the release of arachidonic acid by cytosolic phospholipase A(2) is the rate-limiting step in the generation of eicosanoids and platelet activating factor. These lipid mediators play critical roles in the initiation and modulation of inflammation and oxidative stress. Neurological disorders, such as ischemia, spinal cord injury, Alzheimer's disease, multiple sclerosis, prion diseases, and epilepsy are characterized by inflammatory reactions, oxidative stress, altered phospholipid metabolism, accumulation of lipid peroxides, and increased phospholipase A(2) activity. Increased activities of phospholipases A(2) and generation of lipid mediators may be involved in oxidative stress and neuroinflammation associated with the above neurological disorders. Several phospholipase A(2) inhibitors have been recently discovered and used for the treatment of ischemia and other neurological diseases in cell culture and animal models. At this time very little is known about in vivo neurochemical effects, mechanism of action, or toxicity of phospholipase A(2) inhibitors in human or animal models of neurological disorders. In kainic acid-mediated neurotoxicity, the activities of phospholipase A(2) isoforms and their immunoreactivities are markedly increased and phospholipase A(2) inhibitors, quinacrine and chloroquine, arachidonyl trifluoromethyl ketone, bromoenol lactone, cytidine 5-diphosphoamines, and vitamin E, not only inhibit phospholipase A(2) activity and immunoreactivity but also prevent neurodegeneration, suggesting that phospholipase A(2) is involved in the neurodegenerative process. This also suggests that phospholipase A(2) inhibitors can be used as neuroprotectants and anti-inflammatory agents against neurodegenerative processes in neurodegenerative diseases.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
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Yedgar S, Cohen Y, Shoseyov D. Control of phospholipase A2 activities for the treatment of inflammatory conditions. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1373-82. [PMID: 16978919 DOI: 10.1016/j.bbalip.2006.08.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Accepted: 08/01/2006] [Indexed: 01/10/2023]
Abstract
Phospholipase-A2 (PLA2) enzymes hydrolyze cell membrane phospholipids to produce arachidonic acid (AA) and lyso-phospholipids (LysoPL), playing a key role in the production of inflammatory lipid mediators, mainly eicosanoids. They are therefore considered pro-inflammatory enzymes and their inhibition has long been recognized as a desirable therapeutic target. However, attempts to develop suitable PLA2 inhibitors for the treatment of inflammatory diseases have yet to succeed. This is due to their functional and structural diversity, and their homeostatic and even anti-inflammatory roles in certain circumstances. In the present review we outline the diversity and functions of PLA2 isoforms, and their interplay in the induction and inhibition of inflammatory processes, with emphasis on discussing approaches for therapeutic manipulation of PLA2 activities.
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Affiliation(s)
- Saul Yedgar
- Department of Biochemistry, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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Bacha AB, Gargouri Y, Bezzine S, Mejdoub H. Purification and biochemical characterization of phospholipase A2 from dromedary pancreas. Biochim Biophys Acta Gen Subj 2006; 1760:1202-9. [PMID: 16733083 DOI: 10.1016/j.bbagen.2006.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Revised: 03/09/2006] [Accepted: 03/13/2006] [Indexed: 11/16/2022]
Abstract
Dromedary pancreatic PLA2 (DrPLA2) was purified from delipidated pancreases. Pure protein was obtained after heat and acidic treatment (70 degrees C; pH 3.0), precipitation by ammonium sulphate and ethanol respectively, followed by sequential column chromatographies on Sephadex G-50, MonoS Sepharose, MonoQ Sepharose and C-8 reverse phase high pressure liquid chromatography. Purified DrPLA2, which is not glycosylated protein, was found to be monomeric protein with a molecular mass of 13748.55 Da. A specific activity of 600 U/mg for purified DrPLA2 was measured at optimal conditions (pH 8.0 and 37 degrees C) in the presence of 3 mM NaTDC and 7 mM CaCl(2) using PC as substrate. The sequence of the first fourteen amino-acid residues at the N-terminal extremity of DrPLA2 was determined by automatic Edman degradation. One single sequence was obtained and shows a close similarity with all other known pancreatic secreted phospholipases A2.
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Affiliation(s)
- Abir Ben Bacha
- Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS route de Soukra, 3038 Sfax, Tunisia
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Lessig J, Glander HJ, Schiller J, Petković M, Paasch U, Arnhold J. Destabilization of the acrosome results in release of phospholipase A2 from human spermatozoa and subsequent formation of lysophospholipids. Andrologia 2006; 38:69-75. [PMID: 16529578 DOI: 10.1111/j.1439-0272.2006.00713.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Phospholipase A(2) controls the phospholipid composition in spermatozoal membranes and is released from the acrosome of human spermatozoa. The extracellular phospholipase A(2) activity of human spermatozoa was determined by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry after destabilization of acrosome by the calcium-ionophore calcimycin. MALDI-TOF mass spectrometry allowed the monitoring of changes in both substrate and products of spermatozoal phospholipase A(2) (PLA(2)) without the use of labelled phospholipids. The spermatozoal PLA(2) was characterized as a secretory one (sPLA(2)). Secretory PLA(2) exhibited a high substrate specificity for 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PDPC), the most abundant spermatozoal phospholipid. A time- and cell number-dependent formation of the lysophospholipid PDPC was observed following incubation of extracellular medium of calcimycin-treated spermatozoa (CTS) with PDPC. Antibodies against sPLA(2), specific inhibitors of sPLA(2) and Ca(2+)-chelators could inhibit its generation. An antibody against lysophospholipase enhanced the lysoproduct concentration in the extracellular medium of CTS containing sPLA(2) because further metabolization of these products was blocked. The results demonstrated that destabilization of the acrosome is able to induce a release of secretory phospholipase A(2) from human spermatozoa with subsequent generation of lysophosphocholine in the surrounding of spermatozoa.
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Affiliation(s)
- J Lessig
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Leipzig, Germany
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Simonsen AC, Jensen UB, Hansen PL. Hydrolysis of fluid supported membrane islands by phospholipase A(2): Time-lapse imaging and kinetic analysis. J Colloid Interface Sci 2006; 301:107-15. [PMID: 16765972 DOI: 10.1016/j.jcis.2006.04.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 04/20/2006] [Accepted: 04/20/2006] [Indexed: 10/24/2022]
Abstract
The activity of phospholipase A(2) (PLA(2)) which catalyzes the hydrolysis of phospholipids into free fatty acids and lysolipids, depends on the structure and thermodynamic state of the membrane. To further understand how the substrate conformation correlates with enzyme activity, model systems that are based on time-resolved membrane microscopy are needed. We demonstrate a methodology for preparing and investigating the dynamics of fluid supported phospholipid membranes hydrolyzed by snake venom PLA(2). The method uses quantitative analysis of time-lapse fluorescence images recording the evolution of fluid bilayer islands during hydrolysis. In order to minimize interactions with the support surface, we use double bilayer islands situated on top of a complete primary supported membrane prepared by hydration of spincoated lipid films. Our minimal kinetic analysis describes adsorption of enzyme to the membrane in terms of the Langmuir isotherm as well as enzyme kinetics. We use two related models assuming hydrolysis to occur either at the perimeter or at the surface of the membrane island. We find that the adsorption constant is similar for the two cases, while the estimated turnover rate is markedly different. The PLA(2) concentration series is measured in the absence and presence of beta-cyclodextrin which forms water soluble complexes with the reaction products. The results demonstrate the versatility of double bilayer islands as a membrane model system and introduces a new method for quantifying the kinetics of lipase activity on membranes by directly monitoring the evolution in substrate morphology.
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Affiliation(s)
- Adam Cohen Simonsen
- MEMPHYS, Center for Biomembrane Physics, Physics Department, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Abstract
Several epidemiological studies have indicated that the long-term use of NSAIDs, most of which are cyclo-oxygenase (COX) inhibitors, may reduce the risk of Alzheimer's disease. For this reason, anti-inflammatory COX-inhibiting NSAIDs have received increased attention in experimental and therapeutic trials for Alzheimer's disease. However, several recent efforts attempting to demonstrate a therapeutic effect of NSAIDs in Alzheimer's disease have largely failed. Clinicians and scientists currently believe that this lack of success may be attributable to two key problems: (i) clinical trials of NSAIDs have been conducted in patients with late-stage Alzheimer's disease, wherein advanced neurodegeneration may be refractory to anti-inflammatory drug treatment; and (ii) it is not known which of the large family of NSAIDs (i.e. COX-1, COX-2 or mixed inhibitors) is most efficacious in preventing Alzheimer's disease. The wide list of putative functions for COX in the brain, and the significant functional heterogeneity of NSAIDs, which appear to influence the beta-amyloid (Abeta) neuropathology associated with Alzheimer's disease via both COX-dependent and COX-independent pathways, complicate the interpretation of the mechanisms through which COX-inhibiting NSAIDs may beneficially influence Alzheimer's disease. As discussed in this review, for patients at high risk of developing Alzheimer's disease (e.g. those with mild cognitive impairment), preventative treatment with COX-inhibiting NSAIDs may ultimately represent a viable strategy in the management of clinical Alzheimer's disease. However, the recent evidence showing an increased risk of major cardiovascular events among patients treated with certain COX-1 and COX-2 inhibitors leaves many questions unanswered. We suggest that further investigation into the physiological role(s) of COXs in normal health and in disease conditions, and the identification of safer and better tolerated COX inhibitors, will provide renewed impetus to the application of anti-inflammatory strategies for the prevention and treatment of Alzheimer's disease.
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Affiliation(s)
- Lap Ho
- Department of Psychiatry, The Mount Sinai School of Medicine, Neuroinflammation Research Laboratories, New York, New York 10029, USA
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Paruchuri S, Mezhybovska M, Juhas M, Sjölander A. Endogenous production of leukotriene D4 mediates autocrine survival and proliferation via CysLT1 receptor signalling in intestinal epithelial cells. Oncogene 2006; 25:6660-5. [PMID: 16715140 DOI: 10.1038/sj.onc.1209666] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cysteinyl leukotriene1 (CysLT1) receptor (CysLT1R) enhances survival and proliferation of intestinal cells via distinct pathways. Here, we have demonstrated that there is significant endogenous production of CysLTs from both non-tumour- and tumour-derived intestinal epithelial cells. Treatment of two non-tumour cell lines, Int 407 and IEC-6, with CysLT1R antagonists led to shrinkage and detachment of cells, confirmed as apoptotic cell death, and a dose-dependent reduction in proliferation. However, in the tumour intestinal cell lines Caco-2, SW480, HCT-116 and HT-29, treatment with CysLT1R antagonists significantly reduced proliferation, but had no effect on apoptosis. A unique characteristic of intestinal cancer cells is the presence of nuclear CysLT1Rs, which are inaccessible to receptor antagonists. In these cells, inhibition of the endogenous production of CysLTs indirectly, by 5-lipoxygenase inhibition, impaired CysLT1R signalling throughout the cell, and resulted in apoptosis of the tumour cells. These data reveal the existence of constitutive CysLT1R signalling that mediates both survival and proliferation in intestinal cells. Importantly, we propose that tumour-derived intestinal cells are resistant to CysLT1R antagonist-induced apoptosis, a phenomena that could be explained by nuclear CysLT1R signalling.
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Affiliation(s)
- S Paruchuri
- Cell and Experimental Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
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Liu PY, Li YH, Wu HL, Chao TH, Tsai LM, Lin LJ, Shi GY, Chen JH. Platelet-activating factor-acetylhydrolase A379V (exon 11) gene polymorphism is an independent and functional risk factor for premature myocardial infarction. J Thromb Haemost 2006; 4:1023-8. [PMID: 16689754 DOI: 10.1111/j.1538-7836.2006.01895.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Oxidation of low density lipoproteins is an initial step of atherogenesis that generates pro-inflammatory phospholipids, including platelet-activating factor (PAF). PAF is degraded by PAF-acetylhydrolase (PAF-AH), which has been postulated to be a risk factor for myocardial infarction (MI). The role of PAF-AH for the onset of premature MI is unclear. METHODS Polymorphisms located in putatively functional regions were investigated in a cohort of patients having premature MI onset prior to 46 years of age (n = 200) and a sex-age-matched control group (n = 200). The activity of PAF-AH and coronary angiograms were evaluated for the severity of coronary atherosclerosis. RESULTS The V allele of A379V (exon 11) polymorphism on PAF-AH gene was more frequent in patients with premature MI (P = 0.001). This V allele polymorphism was also associated with a lower activity of plasma PAF-AH and a more complex coronary atherosclerosis (p Trends <0.05). Multiple logistic regression analysis showed that this polymorphism was an independent risk factor (Odds Ratio [OR] 1.66, 95% CI 1.14.1 to 5.80, P = 0.008) as well as smoking (OR 3.72, 95% CI 1.77 to 9.28, P = 0.001), diabetes mellitus (OR 2.25, 95% CI 1.40 to 5.32, P = 0.007) and hypertension (OR 1.88, 95% CI 1.25 to 5.36, P = 0.003) for the onset of premature MI. CONCLUSION We conclude that a functional and significant association between the A379V polymorphism on exon 11 of PAF-AH gene and premature MI exists in this Taiwanese population. This polymorphism is significantly associated with the PAF-AH activity and the severity of coronary atherosclerosis.
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Affiliation(s)
- P-Y Liu
- Division of Cardiology, Departments of Internal Medicine, National Cheng-Kung University Medical Center, 138 Sheng-Li Road, Tainan 704, Taiwan
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Liu NK, Zhang YP, Titsworth WL, Jiang X, Han S, Lu PH, Shields CB, Xu XM. A novel role of phospholipase A2in mediating spinal cord secondary injury. Ann Neurol 2006; 59:606-19. [PMID: 16498630 DOI: 10.1002/ana.20798] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To investigate whether phospholipase A2 (PLA2) plays a role in the pathogenesis of spinal cord injury (SCI). METHODS Biochemical, Western blot, histological, immunohistochemical, electron microscopic, electrophysiological, and behavior assessments were performed to investigate (1) SCI-induced PLA2 activity, expression, and cellular localization after a contusive SCI; and (2) the effects of exogenous PLA2 on spinal cord neuronal death in vitro and tissue damage, inflammation, and function in vivo. RESULTS After SCI, both PLA2 activity and cytosolic PLA2 expression increased significantly, with cytosolic PLA2 expression being localized mainly in neurons and oligodendrocytes. Both PLA2 and melittin, an activator of endogenous PLA2, induced spinal neuronal death in vitro, which was substantially reversed by mepacrine, a PLA2 inhibitor. When PLA2 or melittin was microinjected into the normal spinal cord, the former induced confined demyelination and latter diffuse tissue necrosis. Both injections induced inflammation, oxidation, and tissue damage, resulting in corresponding electrophysiological and behavioral impairments. Importantly, the PLA2-induced demyelination was significantly reversed by mepacrine. INTERPRETATION PLA2, increased significantly after SCI, may play a key role in mediating neuronal death and oligodendrocyte demyelination following SCI. Blocking PLA2 action may represent a novel repair strategy to reduce tissue damage and increase function after SCI.
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Affiliation(s)
- Nai-Kui Liu
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY 40292, USA
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Menschikowski M, Hagelgans A, Siegert G. Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases? Prostaglandins Other Lipid Mediat 2006; 79:1-33. [PMID: 16516807 DOI: 10.1016/j.prostaglandins.2005.10.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/29/2005] [Accepted: 10/31/2005] [Indexed: 02/07/2023]
Abstract
Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie and Laboratoriumsmedizin, Fetscherstrasse 74, D-01307 Dresden, Germany.
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130
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Leng L, Bucala R. Insight into the biology of Macrophage Migration Inhibitory Factor (MIF) revealed by the cloning of its cell surface receptor. Cell Res 2006; 16:162-8. [PMID: 16474429 DOI: 10.1038/sj.cr.7310022] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The recent cloning of MIF receptor fills an important gap in our understanding of the molecular biology and immunology of MIF. The MIF receptor, like MIF, does not fall into any established family of protein mediators, providing both new challenges and opportunities for the structural and functional analysis of MIF signal transduction.
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MESH Headings
- Animals
- Antigens, Differentiation, B-Lymphocyte/chemistry
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Cloning, Molecular
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/metabolism
- Humans
- Macrophage Migration-Inhibitory Factors/chemistry
- Macrophage Migration-Inhibitory Factors/metabolism
- Models, Molecular
- Protein Structure, Quaternary
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- Lin Leng
- Department of Medicine, Yale University School of Medicine, The Anlyan Center, S525, 300 Cedar Street, New Haven CT 06520-8056, USA.
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131
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Sugo T, Tachimoto H, Chikatsu T, Murakami Y, Kikukawa Y, Sato S, Kikuchi K, Nagi T, Harada M, Ogi K, Ebisawa M, Mori M. Identification of a lysophosphatidylserine receptor on mast cells. Biochem Biophys Res Commun 2006; 341:1078-87. [PMID: 16460680 DOI: 10.1016/j.bbrc.2006.01.069] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 01/18/2006] [Indexed: 10/25/2022]
Abstract
Lysophosphatidyl-L-serine (lysoPS) is thought to be an immunological regulator because it dramatically augments the degranulation of rat peritoneal mast cells (RPMCs). This stimulatory effect may be mediated by a lysoPS receptor, but its molecule has not been identified yet. During a ligand fishing study for the orphan G-protein-coupled receptor 34 (GPR34), we found that lysoPS caused a dose-dependent inhibition of forskolin-stimulated cAMP accumulation in human GPR34-expressing Chinese hamster ovary (CHO/hGPR34) cells. The CHO/hGPR34 cells were unresponsive to other structurally related phospholipids examined. Quantitative real-time-PCR demonstrated that mRNAs of GPR34 are particularly abundant in mast cells. The effective lysoPS concentration for RPMC degranulation was similar to that required for GPR34 activation, and the structural requirement of lysoPS for RPMC degranulation was in good agreement with that observed in CHO/hGPR34 cells. These results suggest that GPR34 is the functional mast cell lysoPS receptor.
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Affiliation(s)
- Tsukasa Sugo
- Frontier Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 10 Wadai, Tsukuba, Ibaraki 300-4293, Japan.
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132
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Marusic S, Leach MW, Pelker JW, Azoitei ML, Uozumi N, Cui J, Shen MWH, DeClercq CM, Miyashiro JS, Carito BA, Thakker P, Simmons DL, Leonard JP, Shimizu T, Clark JD. Cytosolic phospholipase A2 alpha-deficient mice are resistant to experimental autoimmune encephalomyelitis. ACTA ACUST UNITED AC 2005; 202:841-51. [PMID: 16172261 PMCID: PMC2212947 DOI: 10.1084/jem.20050665] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Experimental autoimmune encephalomyelitis (EAE), a Th1-mediated inflammatory disease of the central nervous system (CNS), is a model of human multiple sclerosis. Cytosolic phospholipase A2alpha (cPLA2alpha), which initiates production of prostaglandins, leukotrienes, and platelet-activating factor, is present in EAE lesions. Using myelin oligodendrocyte glycoprotein (MOG) immunization, as well as an adoptive transfer model, we showed that cPLA2alpha-/- mice are resistant to EAE. Histologic examination of the CNS from MOG-immunized mice revealed extensive inflammatory lesions in the cPLA2alpha+/- mice, whereas the lesions in cPLA2alpha-/- mice were reduced greatly or completely absent. MOG-specific T cells generated from WT mice induced less severe EAE in cPLA2alpha-/- mice compared with cPLA2alpha+/- mice, which indicates that cPLA2alpha plays a role in the effector phase of EAE. Additionally, MOG-specific T cells from cPLA2alpha-/- mice, transferred into WT mice, induced EAE with delayed onset and lower severity compared with EAE that was induced by control cells; this indicates that cPLA2alpha also plays a role in the induction phase of EAE. MOG-specific T cells from cPLA2alpha-/- mice were deficient in production of Th1-type cytokines. Consistent with this deficiency, in vivo administration of IL-12 rendered cPLA2alpha-/- mice susceptible to EAE. Our data indicate that cPLA2alpha plays an important role in EAE development and facilitates differentiation of T cells toward the Th1 phenotype.
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Affiliation(s)
- Suzana Marusic
- Department of Inflammation, Wyeth Research, Cambridge, MA 02140, USA.
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133
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Piris-Gimenez A, Paya M, Lambeau G, Chignard M, Mock M, Touqui L, Goossens PL. In Vivo Protective Role of Human Group IIA Phospholipase A2against Experimental Anthrax. THE JOURNAL OF IMMUNOLOGY 2005; 175:6786-91. [PMID: 16272335 DOI: 10.4049/jimmunol.175.10.6786] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Anthrax is an acute disease caused by Bacillus anthracis. Some animal species are relatively resistant to anthrax infection. This trait has been correlated to the extent of the local inflammatory reaction, suggesting innate immunity to be the first line of defense against B. anthracis infection in nonimmunized hosts. Group IIA secreted phospholipase A2 (sPLA2-IIA) is produced in particular by macrophages and possesses potent antibacterial activity especially against Gram-positive bacteria. We have previously shown in vitro that sPLA2-IIA kills both germinated B. anthracis spores and encapsulated bacilli. Here we show that sPLA2-IIA plays in vivo a protective role against experimental anthrax. Transgenic mice expressing human sPLA2-IIA are resistant to B. anthracis infection. In addition, in vivo administration of recombinant human sPLA2-IIA protects mice against B. anthracis infection. The protective effect was observed both with a highly virulent encapsulated nontoxinogenic strain and a wild-type encapsulated toxinogenic strain, showing that toxemia did not hinder the sPLA2-IIA-afforded protection. sPLA2-IIA, a natural component of the immune system, may thus be considered a novel therapeutic agent to be used in adjunct with current therapy for treating anthrax. Its anthracidal activity would be effective even against strains resistant to multiple antibiotics.
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Affiliation(s)
- Alejandro Piris-Gimenez
- Unité Toxines et Pathogénie Bactérienne/Centre National de la Recherche Scientifique Unité de Recherche Associée 2172, Paris, France
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134
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Keller CC, Hittner JB, Nti BK, Weinberg JB, Kremsner PG, Perkins DJ. Reduced peripheral PGE2 biosynthesis in Plasmodium falciparum malaria occurs through hemozoin-induced suppression of blood mononuclear cell cyclooxygenase-2 gene expression via an interleukin-10-independent mechanism. Mol Med 2005; 10:45-54. [PMID: 15502882 PMCID: PMC1431354 DOI: 10.2119/2004-00035.perkins] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Molecular immunologic determinants of disease severity during Plasmodium falciparum malaria are largely undetermined. Our recent investigations showed that peripheral blood mononuclear cell (PBMC) cyclooxygenase-2 (COX-2) gene expression and plasma prostaglandin E(2) (PGE(2)) production are suppressed in children with falciparum malaria relative to healthy, malaria-exposed children with partial immunity. Furthermore, decreased COX-2/PGE(2) levels were significantly associated with increased plasma interleukin-10 (IL-10), an anti-inflammatory cytokine that inhibits the expression of COX-2 gene products. To determine the mechanism(s) responsible for COX-2-derived PGE(2) suppression, PBMCs were cultured from children with falciparum malaria. PGE(2) production was suppressed under baseline and COX-2-promoting conditions (stimulation with lipopolysaccharide [LPS] and interferon [IFN]-gamma) over prolonged periods, suggesting that an in vivo-derived product(s) was responsible for reduced PGE(2) biosynthesis. Ingestion of hemozoin (malarial pigment) by PBMC was investigated as a source of COX-2/PGE(2) suppression in PBMCs from healthy, malaria-naive adults. In addition, synthetically prepared hemozoin, beta-hematin, was used to investigate the effects of the core iron component of hemozoin, ferriprotoporphyrin-IX (FPIX). Physiologic concentrations of hemozoin or b-hematin suppressed LPS- and IFN-gamma-induced COX-2 mRNA in a time- and dose-dependent manner, resulting in decreased COX-2 protein and PGE(2) production. Suppression of COX-2/PGE(2) by hemozoin was not due to decreased cell viability as evidenced by examination of mitochondrial bioactivity. These data illustrate that ingestion of FPIX by blood mononuclear cells is responsible for suppression of COX-2/PGE(2). Although hemozoin induced overproduction of IL-10, neutralizing IL-10 antibodies failed to restore PGE(2) production. Thus, acquisition of hemozoin by blood mononuclear cells is responsible for suppression of PGE(2) in malaria through inhibition of de novo COX-2 transcripts via molecular mechanisms independent of increased IL-10 production.
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Affiliation(s)
- Christopher C Keller
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - James B Hittner
- Department of Psychology, College of Charleston, Charleston, South Carolina, USA
| | - Benjamin K Nti
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - J Brice Weinberg
- Department of Medicine, VA and Duke University Medical Centers, Durham, North Carolina, USA
| | - Peter G Kremsner
- Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon
- Department of Parasitology, Institute for Tropical Medicine, University of Tübingen, Germany
| | - Douglas J Perkins
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Address correspondence and reprint requests to Douglas Jay Perkins, University of Pittsburgh, Graduate School of Public Health, Department of Infectious Diseases and Microbiology, 130 DeSoto Street, 603 Parran Hall, Pittsburgh, PA 15261. Phone: 412-624-5894; fax 412-624-4953; e-mail:
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135
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Ryu SB, Lee HY, Doelling JH, Palta JP. Characterization of a cDNA encoding Arabidopsis secretory phospholipase A2-alpha, an enzyme that generates bioactive lysophospholipids and free fatty acids. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1736:144-51. [PMID: 16140037 DOI: 10.1016/j.bbalip.2005.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 08/03/2005] [Accepted: 08/04/2005] [Indexed: 10/25/2022]
Abstract
Phospholipase A2s (PLA2s) are enzymes that liberate lysophospholipids and free fatty acids (FFAs) from membrane phospholipids in response to hormones and other external stimuli. This report describes the cloning and functional characterization of a PLA2 cDNA from Arabidopsis thaliana, AtsPLA2-alpha, which represents one of four secretory PLA2 (sPLA2) genes in Arabidopsis. The encoded protein is 148-amino acid polypeptide and is predicted to contain a 20-amino acid signal peptide at its amino terminus. The predicted mature form (Mr=14,169) of AtsPLA2-alpha exhibited approximately 5 times the specific activity of its pre-processed form. Different from animal sPLA2s, AtsPLA2-alpha showed a significant preference for the acyl group linoleic acid over palmitic acid in phospholipid hydrolysis. Like some animal sPLA2s, however, it has a slight preference for phosphatidylethanolamine over phosphatidylcholine as the substrate. The specific activity of AtsPLA2-alpha continuously increased as the Ca2+ concentration was increased to 10 mM, and the optimal pH range was very broad and biphasic between 6 and 11. AtsPLA2-alpha transcript was detected at low levels in roots, stems, leaves, and flowers but not in siliques.
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Affiliation(s)
- Stephen B Ryu
- Department of Horticulture, University of Wisconsin, 1575 Linden Drive, Madison, WI 53706, USA
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136
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Chalimoniuk M, Głowacka J, Zabielna A, Eckert A, Strosznajder JB. Nitric oxide alters arachidonic acid turnover in brain cortex synaptoneurosomes. Neurochem Int 2005; 48:1-8. [PMID: 16216387 DOI: 10.1016/j.neuint.2005.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Nitric oxide (NO) and arachidonic acid (AA) and also its metabolites are very important inter- and intracellular second messengers. They are involved in mechanisms of learning and memory. However, liberated in excessive amount in brain ischemia, Parkinson and Alzheimer diseases they are responsible for cell degeneration and death. Previously, we could show that Alzheimer disease's amyloid-beta protein enhanced nitric oxide liberation. The role of NO in AA metabolism is till now not well understood. Therefore, the aim of the present study was to investigate the mechanisms of NO-evoked activation of AA release and inhibition of AA incorporation into phospholipids of cortical rat brain synaptoneurosomes. The studies were carried out using NO donors, butyryl-cGMP (b-cGMP) and H2O2. All these compounds enhanced AA liberation from phosphatydilinositol (PI) and phosphatidylcholine (PC). Protein kinase ERK1/2, protein kinase C (PKC), cGMP-dependent protein kinase G (PKG) were involved in basal and NO-induced cytosolic phospholipase A2 (cPLA2) activation. Moreover, NO donors, b-cGMP and hydrogen peroxide (H2O2) exerted inhibitory effect on AA incorporation into PI and PC influencing arachidonyl-CoA transferase (AA-CoA-T) activity. AA-CoA synthase (AA-CoA-S) activity did not change. Specific inhibitors of protein kinase ERK1/2 (UO126), PKC (GF109203X), PKG (KT5823) had no effect on NO-mediated lowering of AA incorporation into PI and PC but inhibited the basal AA-CoA-S activity. Our data indicated that AA (10 microM) itself markedly decreased AA incorporation by about 50% into phospholipids of synaptoneurosomes membranes. Increasing release of AA and its metabolites causes the lowering of AA incorporation evoked by NO, b-cGMP and H2O2. Antioxidant, Resveratrol (100 microM) prevented NO- and cGMP-evoked inhibition of AA incorporation. These results suggest that NO affects the intracellular level of AA through alteration of cPLA2 and AA-CoA acyltransferase activities and may have an important implication in alterations of nerve endings properties and function.
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Affiliation(s)
- Małgorzata Chalimoniuk
- Department of Cellular Signaling, Medical Research Centre, Polish Academy of Sciences, Pawińskiego Street 5, 02-106 Warsaw, Poland.
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137
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Kantarci A, Van Dyke TE. Lipoxin signaling in neutrophils and their role in periodontal disease. Prostaglandins Leukot Essent Fatty Acids 2005; 73:289-99. [PMID: 15979867 DOI: 10.1016/j.plefa.2005.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endogenous molecules involved in counterregulation of inflammatory responses provide an opportunity to explore new therapeutic approaches based on manipulation of new pathways that may reduce the possibility of unwanted toxic side effects. Lipoxins (LX) are trihydroxytetraene-containing eicosanoids that are generated within the vascular lumen during cell-cell interactions or at mucosa through leukocyte-epithelial cell interactions. Transcellular biosynthetic pathways are the major lipoxin biosynthetic routes where LX are formed in vivo during inflammation and serve as "stop signals" that regulate key steps in leukocyte trafficking. In this review, recent findings in lipoxin generation, impact on the resolution of acute inflammation, and organ protection from neutrophil-mediated injury are presented. Periodontitis, specifically localized aggressive periodontitis, which is recognized as an example of neutrophil-mediated tissue injury, is discussed as a disease model where LX and other endogenous pro-resolution pathway mediators could have potential value.
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Affiliation(s)
- Alpdogan Kantarci
- Department of Periodontology and Oral Biology, Boston University Goldman School of Dental Medicine, 100 East Newton Street, G-05, Boston, MA 02118, USA
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138
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Touqui L, Paya M, Thouron F, Guiyoule A, Zarantonelli ML, Leduc D, Wu Y, Taha MK, Alonso JM. Neisseria meningitidispili induce type-IIA phospholipase A2expression in alveolar macrophages. FEBS Lett 2005; 579:4923-7. [PMID: 16115633 DOI: 10.1016/j.febslet.2005.06.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 06/14/2005] [Accepted: 06/15/2005] [Indexed: 11/20/2022]
Abstract
Induction of type-IIA secreted phospholipase A2 (sPLA2-IIA) expression by bacterial components other than lipopolysaccharide has not been previously investigated. Here, we show that exposure of alveolar macrophages (AM) to Neisseria meningitidis or its lipooligosaccharide (LOS) induced sPLA2-IIA synthesis. However, N. meningitidis mutant devoid of LOS did not abolish this effect. In addition, a pili-defective mutant exhibited significantly lower capacity to stimulate sPLA2-IIA synthesis than the wild-type strain. Moreover, pili isolated from a LOS-defective strain induced sPLA2-IIA expression and nuclear factor kappa B (NF-kappaB) activation. These data suggest that pili are potent inducers of sPLA2-IIA expression by AM, through a NF-kappaB-dependent process.
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Affiliation(s)
- Lhousseine Touqui
- Unité de Défense Innée et Inflammation, Inserm E-336, Institut Pasteur, 25 rue du Dr. Roux, 75015 Paris, France.
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139
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Muñoz-Sanjuán I, Brivanlou AH. Induction of ectopic olfactory structures and bone morphogenetic protein inhibition by Rossy, a group XII secreted phospholipase A2. Mol Cell Biol 2005; 25:3608-19. [PMID: 15831466 PMCID: PMC1084286 DOI: 10.1128/mcb.25.9.3608-3619.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The secreted phospholipases A(2) (sPLA(2)s) comprise a family of small secreted proteins with the ability to catalyze the generation of bioactive lipids through glycophospholipid hydrolysis. Recently, a large number of receptor proteins and extracellular binding partners for the sPLA(2)s have been identified, suggesting that these secreted factors might exert a subset of their broad spectrum of biological activities independently of their enzymatic activity. Here, we describe an activity for the sPLA(2) group XII (sPLA(2)-gXII) gene during Xenopus laevis early development. In the ectoderm, sPLA(2)-gXII acts as a neural inducer by blocking bone morphogenetic protein (BMP) signaling. Gain of function in embryos leads to ectopic neurogenesis and to the specification of ectopic olfactory sensory structures, including olfactory bulb and sensory epithelia. This activity is conserved in the Drosophila melanogaster, Xenopus, and mammalian orthologs and appears to be independent of the lipid hydrolytic activity. Because of its effect on olfactory neurogenesis, we have renamed this gene Rossy, in homage to the Spanish actress Rossy de Palma. We present evidence that Rossy/sPLA(2)-gXII can inhibit the transcriptional activation of BMP direct-target gene reporters in Xenopus and mouse P19 embryonic carcinoma cells through the loss of DNA-binding activity of activated Smad1/4 complexes. Collectively, these data represent the first evidence for signaling cross talk between a secreted phospholipase A(2) and the BMP/transforming growth factor beta pathways and identify Rossy/sPLA(2)-gXII as the only factor thus far described which is sufficient to induce anterior sensory neural structures during vertebrate development.
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Affiliation(s)
- Ignacio Muñoz-Sanjuán
- Laboratory of Vertebrate Embryology, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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140
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Mora R, Valverde B, Díaz C, Lomonte B, Gutiérrez JM. A Lys49 phospholipase A(2) homologue from Bothrops asper snake venom induces proliferation, apoptosis and necrosis in a lymphoblastoid cell line. Toxicon 2005; 45:651-60. [PMID: 15777961 DOI: 10.1016/j.toxicon.2005.01.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 01/04/2005] [Accepted: 01/10/2005] [Indexed: 11/27/2022]
Abstract
Lys49 phospholipase A(2) homologues are abundant in viperid snake venoms. These proteins have substitutions at the calcium-binding loop and catalytic center which render them enzymatically inactive; however, they display a series of toxic activities, particularly cytotoxicity upon various cell lines in vitro. In this study we explored whether myotoxin II (MT-II), a Lys49 phospholipase A(2) homologue from the venom of the snake Bothrops asper, is capable of inducing various effects in a single cell type, using the lymphoblastoid B cell line CRL-8062 as a model. Cells were incubated with varying concentrations of MT-II for 24 and 48 h, time intervals that are more prolonged than the usual incubation times previously used in the characterization of this toxin. Results indicate that MT-II induces proliferation at low concentrations (0.5-5.0 microg/mL). Apoptosis was predominant at higher toxin levels (5-25 microg/mL), whereas necrosis, associated with overt plasma membrane disruption, occurred at concentrations > or =25 microg/mL, and was the predominant effect at higher MT-II concentrations (50 microg/mL). It is concluded that a single phospholipase A(2) homologue can induce markedly different effects on a single cell line, depending on the concentration used, an observation that may have implications for the action of this type of venom component in vivo.
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Affiliation(s)
- Rodrigo Mora
- Departamento de Microbiología e Inmunología, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
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141
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Ramoner R, Putz T, Gander H, Rahm A, Bartsch G, Schaber C, Thurnher M. Dendritic-cell activation by secretory phospholipase A2. Blood 2005; 105:3583-7. [PMID: 15494434 DOI: 10.1182/blood-2004-08-3001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractDendritic cells (DCs), also referred to as the sentinels of the immune system, induce and coordinate important functions of immune surveillance. DCs acquire immunity-initiating capacity only after a process of maturation usually induced by ligands that bind to members of the tumor necrosis factor (TNF) or toll-like receptor families. Secretory phospholipase A2 (sPLA2), which hydrolyzes the sn-2 ester bond of glycerophospholipids, regulates a variety of cellular functions including migration of endothelial cells and neurite outgrowth. In the present study we investigated the role of sPLA2 in DC biology. We report that human monocyte-derived DC cultures lack sPLA2 activity but respond to exogenous sPLA2. sPLA2 alone and in cooperation with TNF-α and interleukin 1 β (IL-1β) induced fatty acid release from DC membranes, which was accompanied by upregulation of surface markers and by an increase in the migratory and immunostimulatory capacity of the DCs. Our findings indicate that secreted enzymes such as sPLA2 can contribute to DC maturation and emphasize the role of lipid mediators in the regulation of immune responses. This observation may also have implications for DC-based vaccine development.
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Affiliation(s)
- Reinhold Ramoner
- Department of Urology and Kompetenzzentrum Medizin Tirol (KMT), Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
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142
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Soler-García AA, Maitra R, Kumar V, Ise T, Nagata S, Beers R, Bera TK, Pastan I. The PATE gene is expressed in the accessory tissues of the human male genital tract and encodes a secreted sperm-associated protein. Reproduction 2005; 129:515-24. [PMID: 15798027 DOI: 10.1530/rep.1.00576] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ThePATEgene is expressed in prostate and testis. To determine if PATE is expressed in other accessory tissues of the male genital tract, RT-PCR of the epididymis and seminal vesicle was performed. PATE mRNA was highly expressed in the epididymis and seminal vesicle.In situhybridization of the testis showed PATE mRNA is strongly expressed in the spermatogonia. ThePATEgene encodes a 14-kDa protein with a predicted signal sequence and a cleavage site between residues G21 and S22. To determine if PATE is a secreted protein, 293T cells were transfected with a pcDNA-PATE-myc-His plasmid and protein immunoprecipitated with anti-myc monoclonal antibody. Western blot analysis showed the presence of PATE-myc-His protein was in the medium and the cell lysate. Confocal microscopy demonstrated that PATE-myc-His protein is found in the endoplasmic reticulum. The polyclonal antibody SOL-1 was generated by immunization of rabbits with recombinant PATE protein expressed and purified fromEscherichia coli.Western blots were performed on extracts of prostate, testis, seminal vesicle and ejaculated spermatozoa, but PATE protein was only detected in the spermatozoa. Immunostaining of sperm smears revealed that PATE is located in a band-like pattern in the sperm head. Our data indicate that PATE is made by various sexual accessory tissues and secreted into the semen where it becomes associated with sperm, suggesting that PATE is a novel sperm-associated protein with a possible role in mammalian sperm maturation.
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Affiliation(s)
- Angel A Soler-García
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4264, USA
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143
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Menschikowski M, Hagelgans A, Heyne B, Hempel U, Neumeister V, Goez P, Jaross W, Siegert G. Statins potentiate the IFN-γ-induced upregulation of group IIA phospholipase A2 in human aortic smooth muscle cells and HepG2 hepatoma cells. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:157-71. [PMID: 15863363 DOI: 10.1016/j.bbalip.2005.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 12/20/2004] [Accepted: 01/10/2005] [Indexed: 01/06/2023]
Abstract
The present study shows that the incubation of human aortic smooth muscle cells (HASMC) and HepG2 cells with atorvastatin and mevastatin as HMG-CoA reductase inhibitors potentiated the interferon-gamma (INF-gamma)-induced group IIA phospholipase A(2) (sPLA(2)-IIA) expression in a dose- and time-dependent manner. The effect of statins on sPLA(2)-IIA expression was reduced by mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate. Inversely, inhibitors of the farnesyl transferase and geranylgeranyl transferase-I mimicked the effects of statins. Clostridium difficile toxin B (TcdB), Y-27632 and H-1152, functioning as inhibitors of Rho proteins and Rho-associated kinase, also augmented the sPLA(2)-IIA expression in combination with IFN-gamma. The same effects were observed when inhibitors of mitogen-activated/extracellular response protein kinase kinase (MEK), PD98059 or U0126 were used. Further, the Janus kinase-2 (Jak2)-specific inhibitor, AG-490 and inhibitors of nuclear factor-kappaB (NFkappaB) abrogated the sPLA(2)-IIA elevating effects of statins, TcdB and PD98059 in the presence of IFN-gamma. This cytokine alone increased the NFkappaB p65 and CAAT-enhancer-binding protein-beta (C/EBP-beta) activity in HASMC nuclear extract, but only C/EBP-beta was further augmented when the cells were incubated in addition to IFN-gamma with atorvastatin, H-1152, PD98059 or U0126. Moreover, after the incubation of cells with atorvastatin and IFN-gamma the stability of sPLA-(2)IIA mRNA significantly increased in comparison to those after incubation with IFN-gamma alone. In conclusion, the obtained data suggest that (i) the expression of sPLA(2)-IIA is negatively regulated by RhoA/Rho-associated kinase and MEK/ERK signaling pathways and (ii) statins, because of their ability to down-regulate these pathways, can potentiate the IFN-gamma-induced sPLA(2)-II expression at transcriptional and post-transcriptional levels.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie und Laboratoriumsmedizin, Germany.
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144
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Md S, Moochhala SM, Siew Yang KL, Lu J, Anuar F, Mok P, Ng KC. The role of selective nitric oxide synthase inhibitor on nitric oxide and PGE2 levels in refractory hemorrhagic-shocked rats. J Surg Res 2005; 123:206-14. [PMID: 15680380 DOI: 10.1016/j.jss.2004.07.243] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Indexed: 01/22/2023]
Abstract
BACKGROUND The up-regulation of nitric oxide (NO) and cyclooxgenase-2 (COX-2) has been implicated in the pathophysiology of hemorrhagic shock. We examined the effects of aminoguanidine (AG), which is a known inducible nitric oxide synthase (iNOS) inhibitor, and NS-398, a known COX-2 inhibitor, in our rat model of refractory hemorrhagic shock (RHS). MATERIAL AND METHODS We measured tissue iNOS and COX-2 protein expression, brain and plasma nitrate/nitrite and prostaglandin E2 (PGE2) levels, plasma creatinine and glutamic oxalacetic transaminase (GOT) levels, quantified the histological damages in kidney, liver, lung, and brain, survival rate, and mean arterial blood pressure (MABP) in RHS rats. RESULTS Semiquantitative analysis of tissues showed iNOS protein was not detected in AG + RHS rats but was detected in normal saline and NS-398 RHS rats. Tissue COX-2 protein was not detected in AG and NS-398 RHS rats but was detected in normal saline + RHS rats. The levels of brain and plasma nitrate/nitrite and PGE2 and plasma creatinine and GOT were significantly lower in the AG + RHS rat group when compared with the normal saline RHS rat group. Histological examinations also showed a reduction in organ damage for AG + RHS rats when compared with treated RHS rats. AG + RHS rats showed significantly increased survival and MABP level when compared with treated RHS rats. CONCLUSION Our present findings suggest that NO produced by iNOS might result in organ damages. This in turn might lead to COX-2 up-regulation, and it increases the production of reactive oxygen species and toxic prostanoids. NO-mediated organ damage might be one way in which toxic products of COX-2 might further contribute to NO's deleterious effect in the later stages of RHS. It is therefore suggested that treatment of AG via inhibition of NO might contribute to improved physiological parameters and survival rates following RHS.
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Affiliation(s)
- Shirhan Md
- Department of Pharmacology, National University of Singapore
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145
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Villarrubia VG, Costa LA, Díez RA. [Secreted phospholipases A2 (sPLA2): friends or foes? Are they actors in antibacterial and anti-HIV resistance?]. Med Clin (Barc) 2005; 123:749-57. [PMID: 15574291 DOI: 10.1016/s0025-7753(04)74656-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this paper the authors update on the deletereous or beneficial roles of human and animal secretory phospholipases A2 (sPLA2). Although human sPLA2-IIA (inflammatory) was initially thought as a foe because its pathogenic implication in sepsis, multiorganic failure or other related syndromes, recent data indicates its role in in the antiinfectious host resistance. Thus, sPLA2-IIA exhibits potent bactericidal activities against gram-negative and gram-positive (in this case, together with other endogenous inflammatory factors) bacteria. Surprisingly, human sPLA-IIA does not show in vitro anti-human immunodeficiency virus (HIV) activity, whilst several sPLA2-IA isolated from bee and serpent venons do it: this is the case for crotoxin, a sPLA2-IA isolated from the venon of Crotalus durissus terrificus (sPLA2-Cdt). The mechanism for the in vitro anti-HIV activity of sPLA2-Cdt (inhibition of Gag p24) appears to be related to the ability of the drug to desestabilize ancorage (heparans) and fusion (cholesterol) receptors on HIV target cells.
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146
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Wu WG. Cobra cardiotoxin and phospholipase A2 as GAG-binding toxins: on the path from structure to cardiotoxicity and inflammation. Trends Cardiovasc Med 2005; 8:270-8. [PMID: 14987563 DOI: 10.1016/s1050-1738(98)00019-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glycosaminoglycans (GAGs) represent the sulfated carbohydrate moieties of proteoglycans which occur abundantly in tissues of the cardiovascular system. Many proteins bind specifically to GAGs and perform an important role in inflammation, cell proliferation, and blood coagulation processes. Recently, in vitro GAG-binding studies of cardiotoxins (CTXs) and basic phospholipase A(2) (PLA(2)) from cobra venom established the toxins as two new families of GAG-binding proteins. In particular, discontinuous basic residues in beta-sheet CTXs may form a cationic cradle suitable for heparin binding, as in the case of fibronectin module III-13. The binding specificity of beta-sheet proteins to different GAGs can be further enhanced by involving other cationic clusters near the flexible loop of the molecule. Since the three-dimensional structures of many CTXs and PLA(2) are available, these two toxins may serve as models for the elucidation of the molecular recognition of GAG-binding proteins and also as polypeptide templates for further improvement of the binding specificity suitable for future biomedical application. Research along the line of GAG-guided toxicity of cobra venom components may help us to understand the functional role of GAGs and the action mechanism of cobra venom components in the cardiovascular system.
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Affiliation(s)
- W G Wu
- Department of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan 30043
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147
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Kuwata H, Yamamoto S, Takekura A, Murakami M, Kudo I. Group IIA secretory phospholipase A2 is a unique 12/15-lipoxygenase-regulated gene in cytokine-stimulated rat fibroblastic 3Y1 cells. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1686:15-23. [PMID: 15522818 DOI: 10.1016/j.bbalip.2004.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 07/13/2004] [Accepted: 07/15/2004] [Indexed: 11/29/2022]
Abstract
We have proposed previously that the expression of group IIA secretory phospholipase A(2) (sPLA(2)-IIA), an enzyme implicated in inflammation, is under the control of group IVA cytosolic phospholipase A(2) (cPLA(2)) and 12/15-lipoxygense (12/15-LOX) in cytokine-stimulated rat fibroblastic 3Y1 cells. Here, we show that the reduction of cytokine-stimulated sPLA(2)-IIA induction by the cPLA(2) inhibitor arachidonyl trifluoromethyl ketone (AACOCF(3)) is partially overcome by the addition of various lysophospholipids, such as lysophosphatidylcholine (LysoPC). Furthermore, this lysophospholipid effect was enhanced by further addition of 12/15-LOX products, such as 12(S)- or 15(S)-hydroxyeicosatetraenoic acid (HETE) and 13(S)-hydroxyoctadecadienoic acid (HODE), thus substantiating the hypothesis that the expression of sPLA(2)-IIA is selectively regulated by lipid products of the cPLA(2)-12/15-LOX pathway. In an attempt to identify a set of 12/15-LOX-regulated genes, the cDNA subtraction technique, followed by Northern blotting, was performed to screen particular clones, the expression of which was suppressed by the LOX inhibitor nordihydroguaiaretic acid (NDGA). NDGA-sensitive clones identified thus far included sPLA(2)-IIA, cytoplasmic signaling intermediates, several oxygenases, extracellular matrices, secretory proteins, and other cellular proteins. Of these genes, however, only the expression of sPLA(2)-IIA and 14-3-3eta was enhanced by 12/15-LOX expression. Taken together, our data suggest that sPLA(2)-IIA represents a particular group of genes, the transcription of which is up-regulated by 12/15-LOX metabolites.
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Affiliation(s)
- Hiroshi Kuwata
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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148
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Landreville S, Coulombe S, Carrier P, Gelb MH, Guérin SL, Salesse C. Expression of phospholipases A2 and C in human corneal epithelial cells. Invest Ophthalmol Vis Sci 2004; 45:3997-4003. [PMID: 15505048 PMCID: PMC2424249 DOI: 10.1167/iovs.04-0084] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To achieve a better understanding of the involvement of phospholipases in the inflammation and wound-healing processes in human corneal epithelial cells (HCECs), expression of phospholipase A2s (PLA2s) and phospholipase Cs (PLCs) was examined in the human corneal epithelium. METHODS Specific primers were designed for RT-PCR amplification of the known secreted (s)PLA2, cytosolic (c)PLA2, and PLC mRNAs. Corresponding PCR products were cloned and the DNA sequenced. Immunofluorescence of flatmounted corneal sections and Western blot analyses were used to detect the PLA2s and PLCs expressed by HCECs. RESULTS The mRNAs for the following phospholipases were detected by RT-PCR in the HCECs: sPLA2GIII, -GX, and -GXIIA; cPLA2alpha and -gamma; PLCbeta1, -beta2, -beta3, -beta4, -gamma1, -gamma2, -delta1, -delta3, -delta4, and -epsilon. Immunofluorescence analyses conducted on corneal epithelium cryosections and Western blot on freshly isolated HCECs demonstrated the presence of sPLA2GIII, -GX, and -GXIIA; cPLA2alpha and -gamma; and PLCbeta2, -beta3, -gamma1, -gamma2, and -delta3. CONCLUSIONS Many phospholipase isoforms are expressed by HCECs and may play a major role in signal transduction (PLCs) as well as in the release of precursors of potent mediators of inflammation, such as leukotrienes and prostaglandins (PLA2s). Moreover, the sPLA2s expressed by the corneal epithelium could be involved in the normal antibacterial activity in the tears and in wound healing.
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Affiliation(s)
- Solange Landreville
- Unité de Recherche en Ophtalmologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec (CHUQ), Pavillon du Centre Hospitalier de l’Université Laval (CHUL), Faculté de Médecine
| | - Stéphanie Coulombe
- Unité de Recherche en Ophtalmologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec (CHUQ), Pavillon du Centre Hospitalier de l’Université Laval (CHUL), Faculté de Médecine
| | - Patrick Carrier
- Laboratoire d’Organogenèse Expérimentale, Centre Hospitalier Affilié Universitaire, Pavillon Saint-Sacrement, Université Laval, Sainte-Foy, Québec, Canada
| | - Michael H. Gelb
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington
| | - Sylvain L. Guérin
- Centre de Recherche en Oncologie et Endocrinologie Moléculaire, Centre de Recherche du Centre Hospitalier Universitaire de Québec (CHUQ), Pavillon du Centre Hospitalier de l’Université Laval (CHUL), Faculté de Médecine
| | - Christian Salesse
- Unité de Recherche en Ophtalmologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec (CHUQ), Pavillon du Centre Hospitalier de l’Université Laval (CHUL), Faculté de Médecine
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149
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Seo KH, Lee HS, Jung B, Ko HM, Choi JH, Park SJ, Choi IH, Lee HK, Im SY. Estrogen enhances angiogenesis through a pathway involving platelet-activating factor-mediated nuclear factor-kappaB activation. Cancer Res 2004; 64:6482-8. [PMID: 15374958 DOI: 10.1158/0008-5472.can-03-2774] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this study, we investigated the molecular events involved in estrogen-induced angiogenesis. Treatment of the human endometrial adenocarcinoma cells, HEC-1A, with estrogen up-regulated mRNA expression and protein synthesis of various angiogenic factors such as tumor necrosis factor-alpha, interleukin-1, basic fibroblast growth factor, and vascular endothelial growth factor. The estrogen-dependent induction of the expression was blocked by the platelet-activating factor (PAF) antagonists, WEB 2170. Estrogen treatment caused the activation of nuclear factor (NF)-kappaB in HEC-1A cells and was also blocked by PAF antagonist. Inhibitors of NF-kappaB activation inhibited estrogen-induced mRNA expression and protein synthesis of the angiogenic factors. Estrogen led to a pronounced angiogenesis as assessed by a mouse Matrigel model in vivo and endothelial cell sprouting in vitro. PAF antagonists or NF-kappaB inhibitors significantly inhibited this estrogen-dependent angiogenesis. Estrogen caused phospholipase A2 (PLA2) gene and protein expression. Estrogen-induced vascular endothelial growth factor mRNA expression and sprouting were significantly inhibited by PLA2 inhibitors, suggesting PLA2 expression is the upstream pathway in the estrogen-induced angiogenesis. Taken together, these results suggest that estrogen induces the production of angiogenic factors via a mechanism involving PAF-mediated NF-kappaB activation.
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Affiliation(s)
- Kook Heon Seo
- Department of Biological Sciences, The Institute of Basic Sciences, Hormone Research Center, Chonnam National University, Kwangju, Republic of Korea
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150
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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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