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Taketomi Y, Murakami M. Regulatory Roles of Phospholipase A2 Enzymes and Bioactive Lipids in Mast Cell Biology. Front Immunol 2022; 13:923265. [PMID: 35833146 PMCID: PMC9271868 DOI: 10.3389/fimmu.2022.923265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/30/2022] [Indexed: 11/26/2022] Open
Abstract
Lipids play fundamental roles in life as an essential component of cell membranes, as a major source of energy, as a body surface barrier, and as signaling molecules that transmit intracellular and intercellular signals. Lipid mediators, a group of bioactive lipids that mediates intercellular signals, are produced via specific biosynthetic enzymes and transmit signals via specific receptors. Mast cells, a tissue-resident immune cell population, produce several lipid mediators that contribute to exacerbation or amelioration of allergic responses and also non-allergic inflammation, host defense, cancer and fibrosis by controlling the functions of microenvironmental cells as well as mast cell themselves in paracrine and autocrine fashions. Additionally, several bioactive lipids produced by stromal cells regulate the differentiation, maturation and activation of neighboring mast cells. Many of the bioactive lipids are stored in membrane phospholipids as precursor forms and released spatiotemporally by phospholipase A2 (PLA2) enzymes. Through a series of studies employing gene targeting and lipidomics, several enzymes belonging to the PLA2 superfamily have been demonstrated to participate in mast cell-related diseases by mobilizing unique bioactive lipids in multiple ways. In this review, we provide an overview of our current understanding of the regulatory roles of several PLA2-driven lipid pathways in mast cell biology.
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Murakami M, Taketomi Y. Secreted phospholipase A2 and mast cells. Allergol Int 2015; 64:4-10. [PMID: 25572553 DOI: 10.1016/j.alit.2014.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 12/24/2022] Open
Abstract
Phospholipase A2s (PLA2s) are a group of enzymes that hydrolyze the sn-2 position of phospholipids to release (typically unsaturated) fatty acids and lysophospholipids, which serve as precursors for a variety of bioactive lipid mediators. Among the PLA2 superfamily, secreted PLA2 (sPLA2) enzymes comprise the largest subfamily that includes 11 isoforms with a conserved His-Asp catalytic dyad. Individual sPLA2 enzymes exhibit unique tissue and cellular localizations and specific enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for individual sPLA2 isofoms have revealed their involvement in various pathophysiological events. Here, we overview the current state of knowledge about sPLA2s, specifically their roles in mast cells (MCs) in the context of allergology. In particular, we highlight group III sPLA2 (PLA2G3) as an "anaphylactic sPLA2" that promotes MC maturation and thereby anaphylaxis through a previously unrecognized lipid-orchestrated circuit.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; CREST, Japan Science and Technology Agency, Saitama, Japan.
| | - Yoshitaka Taketomi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Affiliation(s)
- Yoshitaka TAKETOMI
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science
| | - Makoto MURAKAMI
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science
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Murakami M, Taketomi Y, Miki Y, Sato H, Hirabayashi T, Yamamoto K. Recent progress in phospholipase A₂ research: from cells to animals to humans. Prog Lipid Res 2010; 50:152-92. [PMID: 21185866 DOI: 10.1016/j.plipres.2010.12.001] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian genomes encode genes for more than 30 phospholipase A₂s (PLA₂s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA₂s (sPLA₂s), Ca²+-dependent cytosolic PLA₂s (cPLA₂s), Ca²+-independent PLA₂s (iPLA₂s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA₂s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA₂ and iPLA₂ families and the extracellular sPLA₂ family are recognized as the "big three". From a general viewpoint, cPLA₂α (the prototypic cPLA₂ plays a major role in the initiation of arachidonic acid metabolism, the iPLA₂ family contributes to membrane homeostasis and energy metabolism, and the sPLA₂ family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA₂ family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA₂ and sPLA₂ families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA₂ enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA₂ genes. This review focuses on current understanding of the emerging biological functions of PLA₂s and related enzymes.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Rosenson RS, Hislop C, Elliott M, Stasiv Y, Goulder M, Waters D. Effects of varespladib methyl on biomarkers and major cardiovascular events in acute coronary syndrome patients. J Am Coll Cardiol 2010; 56:1079-88. [PMID: 20863951 DOI: 10.1016/j.jacc.2010.06.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 05/19/2010] [Accepted: 06/01/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The purpose of this study was to investigate the effects of varespladib on cardiovascular biomarkers in acute coronary syndrome patients. BACKGROUND Secretory phospholipase A(2) (sPLA(2)) represents a family of proatherogenic enzymes that hydrolyze lipoprotein phospholipids, increasing their affinity for intimal proteoglycans; contribute to cholesterol loading of macrophages by nonscavenger receptor mediated pathways; and activate inflammatory pathways. In prospective studies, high sPLA(2)-IIA levels predicted major adverse cardiovascular events in acute coronary syndrome (ACS) and stable coronary heart disease patients. METHODS This randomized, double-blind, prospective controlled clinical trial (phase 2B) was designed to investigate the effects of sPLA(2) inhibition with varespladib 500 mg daily versus placebo as adjunctive therapy to atorvastatin 80 mg daily on biomarkers (low-density lipoprotein cholesterol [LDL-C], high-sensitivity C-reactive protein [hsCRP], and sPLA(2)-IIA levels), major adverse cardiovascular events (unstable angina, myocardial infarction, death), and safety. In all, 625 ACS subjects were randomized within 96 h of the index event and treated for a minimum of 6 months. RESULTS After 8 weeks (primary efficacy end point), varespladib/atorvastatin reduced mean LDL-C levels from baseline by 49.6% compared with 43.4% with placebo/atorvastatin (p = 0.002). Respective 8-week median reductions in sPLA(2)-IIA levels were 82.4% and 15.6% (p < 0.0001), and hsCRP levels were lowered by 75.0% and 71.0% (p = 0.097). At 24 weeks, respective reductions with varespladib and placebo were as follows: LDL-C 43.5% versus 37.6% (p < 0.05), hsCRP 79.8% versus 77.0% (p = 0.02), and sPLA(2)-IIA 78.5% versus 6.4% (p < 0.0001). Major adverse cardiovascular events were not different from placebo 6 months post-randomization (7.3% varespladib vs. 7.7% placebo). No treatment differences in elevated liver function studies on >1 occasion were observed. CONCLUSIONS Varespladib therapy effectively reduced LDL-C and inflammatory biomarkers in ACS patients treated with conventional therapy including atorvastatin 80 mg daily. There were no treatment differences in clinical cardiovascular events. (FRANCIS [Fewer Recurrent Acute Coronary Events With Near-Term Cardiovascular Inflammation Suppression]-ACS Trial: A Study of the Safety and Efficacy of A 002 in Subjects With Acute Coronary Syndromes; NCT00743925).
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Murakami M, Taketomi Y, Girard C, Yamamoto K, Lambeau G. Emerging roles of secreted phospholipase A2 enzymes: Lessons from transgenic and knockout mice. Biochimie 2010; 92:561-82. [PMID: 20347923 DOI: 10.1016/j.biochi.2010.03.015] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 03/18/2010] [Indexed: 11/15/2022]
Abstract
Among the emerging phospholipase A(2) (PLA(2)) superfamily, the secreted PLA(2) (sPLA(2)) family consists of low-molecular-mass, Ca(2+)-requiring extracellular enzymes with a His-Asp catalytic dyad. To date, more than 10 sPLA(2) enzymes have been identified in mammals. Individual sPLA(2)s exhibit unique tissue and cellular localizations and enzymatic properties, suggesting their distinct pathophysiological roles. Despite numerous enzymatic and cell biological studies on this enzyme family in the past two decades, their precise in vivo functions still remain largely obscure. Recent studies using transgenic and knockout mice for several sPLA(2) enzymes, in combination with lipidomics approaches, have opened new insights into their distinct contributions to various biological events such as food digestion, host defense, inflammation, asthma and atherosclerosis. In this article, we overview the latest understanding of the pathophysiological functions of individual sPLA(2) isoforms fueled by studies employing transgenic and knockout mice for several sPLA(2)s.
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Affiliation(s)
- Makoto Murakami
- Biomembrane Signaling Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Granata F, Nardicchi V, Loffredo S, Frattini A, Ilaria Staiano R, Agostini C, Triggiani M. Secreted phospholipases A(2): A proinflammatory connection between macrophages and mast cells in the human lung. Immunobiology 2009; 214:811-21. [PMID: 19628294 DOI: 10.1016/j.imbio.2009.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)) are an emerging class of mediators of inflammation. These enzymes accumulate in plasma and other biological fluids of patients with inflammatory, autoimmune and allergic diseases. sPLA(2)s are secreted at low levels in the normal airways and tend to increase during inflammatory lung diseases (e.g. bronchial asthma, chronic obstructive pulmonary disease, interstitial lung fibrosis, and sarcoidosis) as the result of plasma extravasation and/or local production. Such immune resident cells as macrophages and mast cells can be a source of sPLA(2)s in the lung. However, these cells are also targets for sPLA(2)s that sustain the activation programs of macrophages and mast cells with mechanism related to their enzymatic activity as well as to their capacity to interact with surface molecules (e.g., heparan sulfate proteoglycans, M-type receptor, mannose receptor). Recent evidence suggests that mast cells are a better source of extracellular sPLA(2)s than macrophages. On the other hand, macrophages appear to be a preferential target for sPLA(2)s. Anatomical association between macrophages and mast cells in the airways suggest that sPLA(2)s released by mast cells may activate in a paracrine fashion several macrophage functions relevant to the modulation of lung inflammation. Thus, sPLA(2)s may play a major role in inflammatory lung diseases by acting as a proinflammatory connection between macrophages and mast cells.
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Affiliation(s)
- Francescopaolo Granata
- Department of Clinical Immunology and Allergy and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy
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Yuan C, Sidhu RS, Kuklev DV, Kado Y, Wada M, Song I, Smith WL. Cyclooxygenase Allosterism, Fatty Acid-mediated Cross-talk between Monomers of Cyclooxygenase Homodimers. J Biol Chem 2009; 284:10046-55. [PMID: 19218248 DOI: 10.1074/jbc.m808634200] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prostaglandin endoperoxide H synthases (PGHSs) 1 and 2, also known as cyclooxygenases (COXs), catalyze the oxygenation of arachidonic acid (AA) in the committed step in prostaglandin (PG) biosynthesis. PGHSs are homodimers that display half of sites COX activity with AA; thus, PGHSs function as conformational heterodimers. Here we show that, during catalysis, fatty acids (FAs) are bound at both COX sites of a PGHS-2 dimer. Initially, an FA binds with high affinity to one COX site of an unoccupied homodimer. This monomer becomes an allosteric monomer, and it causes the partner monomer to become the catalytic monomer that oxygenates AA. A variety of FAs can bind with high affinity to the COX site of the monomer that becomes the allosteric monomer. Importantly, the efficiency of AA oxygenation is determined by the nature of the FA bound to the allosteric monomer. When tested with low concentrations of saturated and monounsaturated FAs (e.g. oleic acid), the rates of AA oxygenation are typically 1.5-2 times higher with PGHS-2 than with PGHS-1. These different kinetic behaviors of PGHSs may account for the ability of PGHS-2 but not PGHS-1 to efficiently oxygenate AA in intact cells when AA is a small fraction of the FA pool such as during "late phase" PG synthesis.
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Affiliation(s)
- Chong Yuan
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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Valera I, Fernández N, Trinidad AG, Alonso S, Brown GD, Alonso A, Crespo MS. Costimulation of dectin-1 and DC-SIGN triggers the arachidonic acid cascade in human monocyte-derived dendritic cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:5727-36. [PMID: 18390758 DOI: 10.4049/jimmunol.180.8.5727] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Inflammatory mediators derived from arachidonic acid (AA) alter the function of dendritic cells (DC), but data regarding their biosynthesis resulting from stimulation of opsonic and nonopsonic receptors are scarce. To address this issue, the production of eicosanoids by human monocyte-derived DC stimulated via receptors involved in Ag recognition was assessed. Activation of FcgammaR induced AA release, short-term, low-grade PG biosynthesis, and IL-10 production, whereas zymosan, which contains ligands of both the mannose receptor and the human beta-glucan receptor dectin-1, induced a wider set of responses including cyclooxygenase 2 induction and biosynthesis of leukotriene C(4) and IL-12p70. The cytosolic phospholipase A(2) inhibitor pyrrolidine 1 completely inhibited AA release stimulated via all receptors, whereas the spleen tyrosine kinase (Syk) inhibitors piceatannol and R406 fully blocked AA release in response to immune complexes, but only partially blocked the effect of zymosan. Furthermore, anti-dectin-1 mAb partially inhibited the response to zymosan, and this inhibition was enhanced by mAb against DC-specific ICAM-3-grabbing nonintegrin (SIGN). Immunoprecipitation of DC lysates showed coimmunoprecipitation of DC-SIGN and dectin-1, which was confirmed using Myc-dectin-1 and DC-SIGN constructs in HEK293 cells. These data reveal a robust metabolism of AA in human DC stimulated through both opsonic and nonopsonic receptors. The FcgammaR route depends on the ITAM/Syk/cytosolic phospholipase A(2) axis, whereas the response to zymosan involves the interaction with the C-type lectin receptors dectin-1 and DC-SIGN. These findings help explain the distinct functional properties of DC matured by immune complexes vs those matured by beta-glucans.
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Affiliation(s)
- Isela Valera
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
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Smith WL. Nutritionally essential fatty acids and biologically indispensable cyclooxygenases. Trends Biochem Sci 2007; 33:27-37. [PMID: 18155912 DOI: 10.1016/j.tibs.2007.09.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 09/27/2007] [Accepted: 09/28/2007] [Indexed: 02/02/2023]
Abstract
The study of cyclooxygenases (COXs), targets of aspirin and related drugs, is rooted in the discovery of essential fatty acids (EFAs). There are two COXs that convert EFAs, primarily arachidonic acid, to prostaglandins. Each COX is involved with distinct biologies. COX-1 expression is constitutive while COX-2 is inducible. The two COXs might have evolved partly to permit prostaglandin formation at different tissue sites. However, COX-2 is sometimes induced in cells already expressing COX-1, and in these instances, COX-2 functions while COX-1 is latent. This can occur because of unique biochemical properties of COX-2 that enable cells to form prostaglandins when arachidonic acid comprises a small fraction of available fatty acids and the concentrations of peroxides that are necessary for COX to function are low.
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Affiliation(s)
- William L Smith
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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Grosman N. Comparison of the influence of NSAIDs with different COX-selectivity on histamine release from mast cells isolated from naïve and sensitized rats. Int Immunopharmacol 2007; 7:532-40. [PMID: 17321477 DOI: 10.1016/j.intimp.2006.12.010] [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: 12/07/2006] [Revised: 12/20/2006] [Accepted: 12/21/2006] [Indexed: 01/04/2023]
Abstract
Mast cell stimulation leads to an early response with histamine release and prostaglandin (PGD(2)) production but attempts to link these two events have been contradictory. In IgE-mediated mast cell activation, a late-phase PGD(2)-production is caused by increased cyclooxygenase-2 (COX-2) expression whereas a COX-2 involvement in the early response is uncertain. The present study compares the influence of four COX-inhibitors (NSAIDs) on the histamine release of mast cells from naïve and actively sensitized rats. NSAIDs of different COX-1 vs. COX-2 selectivity were used, i.e. acetylsalicylic acid (ASA), piroxicam, meloxicam, and NS-398, a selective COX-2-inhibitor. All could inhibit antigen-induced histamine release, with 64%, 34%, 27% and 85% inhibition by ASA (5 mM), piroxicam (100 microM), meloxicam (100 microM) and NS-398 (100 microM), respectively. Similar inhibition was found with compound 48/80 without calcium added to the medium whereas compound 48/80 with calcium was affected less by ASA and NS-398 and unaffected by the oxicams. Only small differences between the two kinds of mast cells were found, except with NS-398 which was a significantly more effective inhibitor of naïve than sensitized cells when exposed to compound 48/80 with calcium present. The results do not show any consistent relationship between the influence of the NSAIDs and their COX-2-selectivity. The high NSAID-concentrations required for inhibition cast doubt about an involvement of COX-inhibition and indicate additional or other targets. The results seem to exclude toxic effects on mast cell energy production but are consistent with an interference with the calcium disposition.
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Affiliation(s)
- Nina Grosman
- Department of Pharmacology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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Diaz BL, Satake Y, Kikawada E, Balestrieri B, Arm JP. Group V secretory phospholipase A2 amplifies the induction of cyclooxygenase 2 and delayed prostaglandin D2 generation in mouse bone marrow culture-derived mast cells in a strain-dependent manner. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1489-97. [PMID: 17064958 PMCID: PMC1764612 DOI: 10.1016/j.bbalip.2006.09.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 08/15/2006] [Accepted: 09/06/2006] [Indexed: 11/30/2022]
Abstract
Activation of mouse bone marrow-derived mast cells (BMMC) with stem cell factor (SCF) or IgE and antigen elicits exocytosis and an immediate phase of prostaglandin (PG) D(2) and leukotriene (LT) C(4) generation. Activation of BMMC by SCF, IL-1beta and IL-10 elicits a delayed phase of PGD(2) generation dependent on cyclooxygenase (COX) 2 induction. Cytosolic phospholipase A(2) alpha provides arachidonic acid in both phases and amplifies COX-2 induction. Pharmacological experiments implicate an amplifying role for secretory (s) PLA(2). We used mice lacking the gene encoding group V sPLA(2) (Pla2g5-/-) to definitively test its role in eicosanoid generation by BMMC. Pla2g5-/- BMMC on a C57BL/6 genetic background showed a modest reduction in exocytosis and immediate PGD(2) generation after activation with SCF or with IgE and antigen, while LTC(4) generation was not modified. Delayed-phase PGD(2) generation and COX-2 induction were reduced approximately 35% in C57BL/6 Pla2g5-/- BMMC and were restored by exogenous PGE(2). There was no deficit in either phase of eicosanoid generation by Pla2g5-/- BMMC on a BALB/c background. Thus, group V sPLA(2) amplifies COX-2 expression and delayed phase PGD(2) generation in a strain-dependent manner; it has at best a limited role in immediate eicosanoid generation by BMMC.
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Affiliation(s)
- Bruno L. Diaz
- Department of Medicine Harvard Medical School and the Division of Rheumatology Immunology and Allergy, Brigham and Women’s Hospital, Boston, MA
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil 20231-050
| | - Yoshiyuki Satake
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil 20231-050
| | - Eriya Kikawada
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil 20231-050
| | - Barbara Balestrieri
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil 20231-050
| | - Jonathan P. Arm
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil 20231-050
- Partners Asthma Center, Brigham and Women’s Hospital, Boston, MA
- *Corresponding Author. Smith Research Building, Room 638B 1, Jimmy Fund Way Boston, MA 02115 Tel (617) 525-1305; Fax (617 525-1310 E-Mail:
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Balestrieri B, Arm JP. Group V sPLA2: classical and novel functions. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1280-8. [PMID: 16945583 DOI: 10.1016/j.bbalip.2006.07.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 07/20/2006] [Accepted: 07/25/2006] [Indexed: 10/24/2022]
Abstract
Group V sPLA(2) is unique among the family of secretory sPLA(2) enzymes in being able to bind to cell membranes through both interfacial-binding and through binding to proteoglycan. The function of group V sPLA(2) as an enzyme and its cross-talk with cPLA(2)alpha in initiating eicosanoid generation is well documented. Evidence, though, is emerging on the ability of this molecule to act as a regulator of several intracellular and extracellular pathways independently of its ability to provide arachidonic acid for eicosanoid generation, acting within the cell or as a secreted enzyme. In this article we will provide an overview of the properties of the enzyme and how they relate to our current understanding of its function.
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Affiliation(s)
- Barbara Balestrieri
- Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA
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Li Q, Subbulakshmi V, Oldfield CM, Aamir R, Weyman CM, Wolfman A, Cathcart MK. PKCalpha regulates phosphorylation and enzymatic activity of cPLA2 in vitro and in activated human monocytes. Cell Signal 2006; 19:359-66. [PMID: 16963226 DOI: 10.1016/j.cellsig.2006.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 07/18/2006] [Indexed: 11/19/2022]
Abstract
Phospholipases A(2) (PLA(2)) are potent regulators of the inflammatory response. We have observed that Group IV cPLA(2) activity is required for the production of superoxide anion (O(2)(-)) in human monocytes [Li Q., Cathcart M.K. J. Biol. Chem. 272 (4) (1997) 2404-2411.]. We have previously identified PKCalpha as a kinase pathway required for monocyte O(2)(-) production [Li Q., Cathcart M.K. J. Biol. Chem. 269 (26) (1994) 17508-17515.]. We therefore investigated the potential interaction between PKCalpha and cPLA(2) by evaluating the requirement for specific PKC isoenzymes in the process of activating cPLA(2) enzymatic activity and protein phosphorylation upon monocyte activation. We first showed that general PKC inhibitors and antisense oligodeoxyribonucleotides (ODN) to the cPKC group of PKC enzymes inhibited cPLA(2) activity. To distinguish between PKCalpha and PKCbeta isoenzymes in regulating cPLA(2) protein phosphorylation and enzymatic activity, we employed our previously characterized PKCalpha or PKCbeta isoenzyme-specific antisense ODN [Li Q., Subbulakshmi V., Fields A.P., Murray, N.R., Cathcart M.K., J. Biol. Chem. 274 (6) (1999) 3764-3771]. Suppression of PKCalpha expression, but not PKCbeta expression, inhibited cPLA(2) protein phosphorylation and enzymatic activity. Additional studies ruled out a contribution by Erk1/2 to cPLA(2) phosphorylation and activation. We also found that cPLA(2) co-immunoprecipitated with PKCalpha and vice versa. In vitro studies demonstrated that PKCalpha could directly phosphorylate cPLA(2).and enhance enzymatic activity. Finally, we showed that addition of arachidonic acid restored the production of O(2)(-) in monocytes defective in either PKCalpha or cPLA(2) expression. Taken together, our data suggest that PKCalpha, but not PKCbeta, is the predominant cPKC isoenzyme required for cPLA(2) protein phosphorylation and maximal induction of cPLA(2) enzymatic activity upon activation of human monocytes. Our data also support the concept that the requirements for PKCalpha and cPLA(2) in O(2)(-) generation are solely due to their seminal role in generating arachidonic acid.
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Affiliation(s)
- Qing Li
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Son MJ, Moon TC, Lee EK, Son KH, Kim HP, Kang SS, Son JK, Lee SH, Chang HW. Naturally occurring biflavonoid, ochnaflavone, inhibits cyclooxygenases-2 and 5-lipoxygenase in mouse bone marrow-derived mast cells. Arch Pharm Res 2006; 29:282-6. [PMID: 16681032 DOI: 10.1007/bf02968571] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Ochnaflavone is a medicinal herbal product isolated from Lonicera japonica that inhibits cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 (PGD2) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with IC50 values of 0.6 microM. Western blotting probed with specific anti-COX-2 antibodies showed that the decrease in quantity of the PGD2 product was accompanied by a decrease in the COX-2 protein level. In addition, this compound consistently inhibited the production of leukotriene C4 (LTC4) in a dose dependent manner, with an IC50 value of 6.56 microM. These results demonstrate that ochnaflavone has a dual cyclooxygenase-2/5-lipoxygenase inhibitory activity. Furthermore, this compound strongly inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 3.01 microM. Therefore, this compound might provide a basis for novel anti-inflammatory drugs.
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Affiliation(s)
- Min Jung Son
- Skeletal Diseases Genome Research Center, Kyungpook National University, Daegu 702-701, Korea
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Lee E, Haa K, Yook JM, Jin MH, Seo CS, Son KH, Kim HP, Bae KH, Kang SS, Son JK, Chang HW. Anti-asthmatic activity of an ethanol extract from Saururus chinensis. Biol Pharm Bull 2006; 29:211-5. [PMID: 16462020 DOI: 10.1248/bpb.29.211] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As an attempt to find bioactive medicinal herbs exerting anti-asthmatic activity, the effects of an ethanol extract from the parts of Saururus chinensis were evaluated in both in vitro and in vivo. The ethanol extract of S. chinensis (ESC) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D(2) in bone marrow-derived mast cells in a concentration-dependent manner with an IC(50) value of 14.3 microg/ml. ESC also inhibited leukotriene C(4) production with an IC(50) value of 0.3 microg/ml. This demonstrates that ESC has COX-2/5-lipoxygenase dual inhibitory activity. In addition, this compound inhibited degranulation reaction in a dose dependent manner, with an IC(50) value of 1.3 microg/ml. An ovalbumin induced mouse asthmatic animal model was used to determine its in vivo anti-asthmatic activity. The oral administration (50-200 mg/kg) of ESC reduced the number of infiltrated eosinophil in a bronchoalveolar lavage fluid. Furthermore, ESC (100 mg/kg) inhibited the eotaxin and IL-4 mRNA expression levels. These results suggest that the anti-asthmatic activity of S. chinensis might in part occur via the inhibition of eicosanoid generation, degranulation as well as the down regulation of IL-4 and eotaxin mRNA expression.
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Affiliation(s)
- Eunkyung Lee
- College of Pharmacy, Yeungnam University, Gyeongsan 712-749, Korea
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17
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Jin MH, Yook J, Lee E, Lin CX, Quan Z, Son KH, Bae KH, Kim HP, Kang SS, Chang HW. Anti-inflammatory Activity of Ailanthus altissima in Ovalbumin-Induced Lung Inflammation. Biol Pharm Bull 2006; 29:884-8. [PMID: 16651713 DOI: 10.1248/bpb.29.884] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As part of an ongoing investigation to find bioactive medicinal herbs exerting anti-inflammation activity, the effect of an ethanol extract from the parts of Ailanthus altissima (Simaroubaceae) was evaluated in both in vitro and in in vivo system. The ethanol extract of A. altissima (EAa) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with an IC50 value of 214.6 microg/ml. However, this compound did not inhibit COX-2 protein expression up to a concentration of 400 microg/ml in the BMMC, indicating that EAa directly inhibits COX-2 activity. In addition, EAa inhibited leukotriene C4 production with an IC50 value of 25.7 microg/ml. Furthermore, this compound inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 27.3 microg/ml. Ovalbumin (OVA)-sensitized mice were orally pretreated with EAa before aerosol challenges. EAa reduced the eosinophil infiltration into the airway and the eotaxin, IL-4, and IL-13 mRNA expression levels. These results suggest that the anti-inflammation activity of A. altissima in OVA-induced lung inflammation may occur in part via the down regulation of T(H)2 cytokines and eotaxin transcripts as well as the inhibition of inflammatory mediators.
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Affiliation(s)
- Mei Hua Jin
- College of Pharmacy, Yeungnam University, Gyongsan, Korea
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18
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Triggiani M, Granata F, Giannattasio G, Marone G. Secretory phospholipases A2 in inflammatory and allergic diseases: not just enzymes. J Allergy Clin Immunol 2005; 116:1000-6. [PMID: 16275367 DOI: 10.1016/j.jaci.2005.08.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 08/04/2005] [Accepted: 08/08/2005] [Indexed: 12/30/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are molecules released in plasma and biologic fluids of patients with systemic inflammatory, autoimmune, and allergic diseases. Several sPLA(2) isoforms are expressed and released by such human inflammatory cells as neutrophils, eosinophils, basophils, T cells, monocytes, macrophages, and mast cells. Certain sPLA(2)s release arachidonic acid, thereby providing the substrate for the biosynthesis of proinflammatory eicosanoids. However, there are other mechanisms by which sPLA(2)s might participate in the synthesis of lipid mediators. Interestingly, sPLA(2)s activate inflammatory cells through mechanisms unrelated to their enzymatic activity. Several sPLA(2)s induce degranulation of mast cells and eosinophils and activate exocytosis in macrophages. Furthermore, sPLA(2)s promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes, and endothelial cells. Some of these effects are mediated by the binding of sPLA(2)s to specific receptors expressed on effector cells. Thus sPLA(2)s might play important roles in the initiation and amplification of the inflammatory reaction. Selective inhibitors of sPLA(2)s and specific antagonists of sPLA(2) receptors might prove useful in the treatment of allergic and autoimmune diseases, such as bronchial asthma and rheumatoid arthritis.
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Affiliation(s)
- Massimo Triggiani
- Division of Clinical Immunology and Allergy, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, Naples, Italy
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Choi YH, Son KH, Chang HW, Bae K, Kang SS, Kim HP. New anti-inflammatory formulation containing Synurus deltoides extract. Arch Pharm Res 2005; 28:848-53. [PMID: 16114500 DOI: 10.1007/bf02977352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Synurus deltoides was previously found to possess significant anti-inflammatory activity especially against chronic inflammation, and strong analgesic activity in vivo. In this study, new anti-inflammatory formulation containing S. deltoides extract as a major ingredient was prepared and in vivo activity was evaluated. The plausible action mechanism was also investigated. The new formulation (SAG) contains 1 part of S. deltoides extract, 0.9 part of Angelica gigas extract and 0.9 part of glucosamine sulfate (w/w). SAG inhibited dose-dependently edematic response of arachidonic acid (AA)- and 12-O-tetradecanoyl 13-acetate (TPA)-induced ear edema in mice, which is an animal model of acute inflammation. SAG showed 44.1% inhibition of AA-induced ear edema at an oral dose of 50 mg/kg. In an animal model of chronic inflammation, SAG clearly reduced the edematic response of 7-day model of multiple treatment of TPA (38.1% inhibition at 200 mg/kg/day). Furthermore, SAG (50-800 mg/kg/day) as well as S. deltoides extract (285 mg/kg/day) significantly inhibited prostaglandin E2 production from the skin lesion of the animals of 7-day model. These results were well correlated with in vitro finding that SAG as well as S. deltoides extract reduced cyclooxygenase (COX)-1- and COX-2-induced prostanoid production, measured in mouse bone marrow-derived mast cells. Therefore, these results suggest that SAG possesses anti-inflammatory activity in vivo against acute as well as chronic inflammatory animal models at least in part by inhibition of prostaglandin production through COX-1/COX-2 inhibition. And COX inhibition of SAG is possibly contributed by S. deltoides extract among the ingredients. Although the anti-inflammatory potencies of SAG were less than those of currently used anti-inflammatory drugs, this formulation may have beneficial effect on inflammatory disorders as a neutraceutical.
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Affiliation(s)
- Yong Hwan Choi
- College of Pharmacy, Kangwon National University, Chunchon 200-701, Korea
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20
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Shirai Y, Balsinde J, Dennis EA. Localization and functional interrelationships among cytosolic Group IV, secreted Group V, and Ca2+-independent Group VI phospholipase A2s in P388D1 macrophages using GFP/RFP constructs. BIOCHIMICA ET BIOPHYSICA ACTA 2005; 1735:119-29. [PMID: 15967714 DOI: 10.1016/j.bbalip.2005.05.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 04/28/2005] [Accepted: 05/05/2005] [Indexed: 10/25/2022]
Abstract
P388D(1) cells exposed to bacterial lipopolysaccharide (LPS) mobilize arachidonic acid (AA) for prostaglandin synthesis in two temporally distinct pathways. The "immediate pathway" is triggered within minutes by receptor agonists such as platelet-activating factor (PAF) but only if the cells have previously been primed with LPS for 1 h. The "delayed pathway" occurs in response to LPS alone over the course of several hours. We have now investigated the subcellular localization of both the Group IV cytosolic phospholipase A(2) (cPLA(2)) and the Group V secreted PLA(2) (sPLA(2)) during these two temporally distinct routes of AA release. We have prepared cells overexpressing fusion proteins of sPLA(2)-GFP and cPLA(2)-RFP. In the resting cells, cPLA(2)-RFP was uniformly located throughout the cytoplasm, and short-term treatment with LPS did not induce translocation to perinuclear and/or Golgi membranes. However, such a translocation occurred almost immediately after the addition of PAF to the cells. Long-term exposure of the cells to LPS led to the translocation of cPLA(2)-RFP to intracellular membranes after 3 h, and correlates with a significant release of AA in a cPLA(2)-dependent manner. At the same time period that the delayed association of cPLA(2) with perinuclear membranes is detected, an intense fluorescence arising from the sPLA(2)-GFP was found around the nucleus in the sPLA(2)-GFP stably transfected cells. In parallel with these changes, significant AA release was detected from the sPLA(2)-GFP transfectants in a cPLA(2)-dependent manner, which may reflect cross-talk between sPLA(2) and cPLA(2). The subcellular localization of the Group VIA Ca(2+)-independent PLA(2) (iPLA(2)) was also investigated. Cells overexpressing iPLA(2)-GFP showed no fluorescence changes under any activation condition. However, the iPLA(2)-GFP-expressing cells showed relatively high basal AA release, confirming a role for iPLA(2) in basal deacylation reactions. These new data illustrate the subcellular localization changes that accompany the distinct roles that each of the three kinds of PLA(2) present in P388D(1) macrophages play in AA mobilization.
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Affiliation(s)
- Yasuhito Shirai
- Department of Chemistry and Biochemistry, School of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0601, USA
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21
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22
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Lee SH, Son MJ, Ju HK, Lin CX, Moon TC, Choi HG, Son JK, Chang HW. Dual inhibition of cyclooxygenases-2 and 5-lipoxygenase by deoxypodophyllotoxin in mouse bone marrow-derived mast cells. Biol Pharm Bull 2005; 27:786-8. [PMID: 15187418 DOI: 10.1248/bpb.27.786] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Deoxypodophyllotoxin (Anthricin) is a medicinal herbal product isolated from Anthriscus sylvestris HOFFM. that inhibits cyclooxygenase-2 (COX-2) and COX-1-dependent phases of prostaglandin D(2) (PGD(2)) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with IC(50) values of 1.89 microM and 65.3 microM, respectively. This study also found that this compound inhibited COX-1 and 2-dependent conversion of the exogenous arachidonic acid to PGD(2) in a dose-dependent manner with an IC(50) values of 0.01 microM and 12.1 microM, respectively using a COX enzyme assay kit. However, this compound did not inhibit COX-2 protein expression up to a concentration of 30 microM in the BMMC, indicating that deoxypodophyllotoxin directly inhibits COX-2 activity. Furthermore, this compound consistently inhibited the production of leukotriene C(4) (LTC(4)) in a dose dependent manner, with an IC(50) value of 0.37 microM. These results demonstrate that deoxypodophyllotoxin has a dual cyclooxygenase-2 selective/5-lipoxygenase inhibitory activity, and therefore this compound might provide a basis for novel anti-inflammatory drugs.
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Affiliation(s)
- Seung Ho Lee
- College of Pharmacy, Yeungnam University, Gyongsan, Japan
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23
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Moon TC, Lin CX, Lee JS, Kim DS, Bae K, Son KH, Kim HP, Kang SS, Son JK, Chang HW. Antiinflammatory Activity of Astilbic Acid from Astilbe chinensis. Biol Pharm Bull 2005; 28:24-6. [PMID: 15635157 DOI: 10.1248/bpb.28.24] [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] [Indexed: 11/22/2022]
Abstract
This study examined the effect of astilbic acid (3beta,6beta-dihydroxyolean-12-en-27-oic acid), which is a herbal medicine isolated from Astilbe chinensis. Astilbic acid inhibited 5-lipoxygenase (5-LOX)-dependent leukotriene C4 (LTC4) generation in bone marrow-derived mast cells in a concentration-dependent manner with an IC50 value of 2.1 microM. In addition, astilbic acid was tested in a rat passive cutaneous anaphylaxis (PCA) reaction assay by administering 10 to 50 mg/kg i.p. Astilbic acid dose dependently inhibited the PCA reaction, which was activated by anti-dinitrophenyl (DNP) IgE. Furthermore, this compound inhibited mouse acetic acid-induced writhing (47-62% inhibition at 0.4-50 mg/kg) after being administered orally, while aspirin (200 mg/kg) showed 62% inhibition. These results suggest that astilbic acid may be beneficial in regulating various inflammatory processes.
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Affiliation(s)
- Tae Chul Moon
- College of Pharmacy, Yeungnam University, Gyongsan, Korea
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24
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Rouzer CA, Kingsley PJ, Wang H, Zhang H, Morrow JD, Dey SK, Marnett LJ. Cyclooxygenase-1-dependent prostaglandin synthesis modulates tumor necrosis factor-alpha secretion in lipopolysaccharide-challenged murine resident peritoneal macrophages. J Biol Chem 2004; 279:34256-68. [PMID: 15181007 DOI: 10.1074/jbc.m402594200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Comprehensive studies of prostaglandin (PG) synthesis in murine resident peritoneal macrophages (RPM) responding to bacterial lipopolysaccharide (LPS) revealed that the primary PGs produced by RPM were prostacyclin and PGE(2). Detectable increases in net PG formation occurred within the first hour, and maximal PG formation had occurred by 6-10 h after LPS addition. Free arachidonic acid levels rose and peaked at 1-2 h after LPS addition and then returned to baseline. Cyclooxygenase-2 (COX-2) and microsomal PGE synthase levels markedly increased upon exposure of RPM to LPS, with the most rapid increases in protein expression occurring 2-6 h after addition of the stimulus. RPM constitutively expressed high levels of COX-1. Studies using isoform-selective inhibitors and RPM from mice bearing targeted deletions of ptgs-1 and ptgs-2 demonstrated that COX-1 contributes significantly to PG synthesis in RPM, especially during the initial 1-2 h after LPS addition. Selective inhibition of either COX isoform resulted in increased secretion of tumor necrosis factor-alpha (TNF-alpha); however, this effect was much greater with the COX-1 than with the COX-2 inhibitor. These results demonstrate autocrine regulation of TNF-alpha secretion by endogenous PGs synthesized primarily by COX-1 in RPM and suggest that COX-1 may play a significant role in the regulation of the early response to endotoxemia.
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Affiliation(s)
- Carol A Rouzer
- Departments of Biochemistry and Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University School of medicine, Nashville, TN 37232-0146.
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25
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Tashiro S, Sumi T, Uozumi N, Shimizu T, Nakamura T. B-Myb-Dependent Regulation of c-Myc Expression by Cytosolic Phospholipase A2. J Biol Chem 2004; 279:17715-22. [PMID: 14769798 DOI: 10.1074/jbc.m310561200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytosolic phospholipase A(2) (cPLA(2)) cleaves membrane phospholipids to release arachidonic acid, initiating lipoxygenase and cyclooxygenase pathways. Mice lacking a gene for cPLA(2) suggested important roles of the protein in allergic responses, fertility, and neural cell death. Here we show that cPLA(2) negatively regulates c-Myc expression in a B-Myb-dependent manner. Overexpression of cPLA(2) protein but not a mutant cPLA(2) protein that lacks in vitro binding ability with B-Myb inhibits B-Myb-dependent c-myc gene expression. The inhibition was associated with physical interaction of B-Myb protein with cPLA(2) both in the cytoplasm and the nucleus. Binding site analysis demonstrated that both the N and C termini of cPLA(2) interact with B-Myb. Macrophage colony stimulating factor (MCSF) stimulated cPLA(2) redistribution into the nucleus and also association with B-Myb in human monocytes. Importantly, macrophages from mice with a disrupted cPLA(2) gene demonstrated significantly increased levels of c-Myc protein in the nucleus compared with cells from the wild-type mice, whereas B-Myb levels were similar in the cells from the cPLA(2)(+/+) and cPLA(2)(-/-) mice. Moreover, an introduction of cPLA(2) into cPLA(2)(-/-) mouse macrophages resulted in decreased c-Myc protein levels, and an inhibition of cPLA(2) expression by small interfering RNAs or antisense RNA increased the c-myc transcription in macrophage colony stimulating factor-activated human monocytes. These findings provide new insights into the function of cPLA(2) in B-Myb-dependent gene expression.
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Affiliation(s)
- Shigeki Tashiro
- Department of Radiology and Cancer Biology, Nagasaki University School of Dentistry, Nagasaki 852-8588, Japan
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26
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Satake Y, Diaz BL, Balestrieri B, Lam BK, Kanaoka Y, Grusby MJ, Arm JP. Role of group V phospholipase A2 in zymosan-induced eicosanoid generation and vascular permeability revealed by targeted gene disruption. J Biol Chem 2004; 279:16488-94. [PMID: 14761945 PMCID: PMC1201398 DOI: 10.1074/jbc.m313748200] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conclusions regarding the contribution of low molecular weight secretory phospholipase A2 (sPLA2) enzymes in eicosanoid generation have relied on data obtained from transfected cells or the use of inhibitors that fail to discriminate between individual members of the large family of mammalian sPLA2 enzymes. To elucidate the role of group V sPLA2, we used targeted gene disruption to generate mice lacking this enzyme. Zymosan-induced generation of leukotriene C4 and prostaglandin E2 was attenuated approximately 50% in peritoneal macrophages from group V sPLA2-null mice compared with macrophages from wild-type littermates. Furthermore, the early phase of plasma exudation in response to intraperitoneal injection of zymosan and the accompanying in vivo generation of cysteinyl leukotrienes were markedly attenuated in group V sPLA2-null mice compared with wild-type controls. These data provide clear evidence of a role for group V sPLA2 in regulating eicosanoid generation in response to an acute innate stimulus of the immune response both in vitro and in vivo, suggesting a role for this enzyme in innate immunity.
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Affiliation(s)
- Yoshiyuki Satake
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
| | - Bruno L. Diaz
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
- Divisão de Biologia Celular, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil
| | - Barbara Balestrieri
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
| | - Bing K. Lam
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
| | - Yoshihide Kanaoka
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
| | - Michael J. Grusby
- Department of Immunology and Infectious Disease, Harvard School of Public Health, Boston, MA 02115
| | - Jonathan P. Arm
- Department of Medicine Harvard Medical School, Boston, MA 02115
- Division of Rheumatology Immunology and Allergy, and the
- Partners Asthma Center, Brigham and Women’s Hospital, Boston, MA 02115
- §§ To whom correspondence should be addressed: Brigham and Women’s Hospital, Smith Research Building, Room 638B, 1, Jimmy Fund Way, Boston, MA 02115. Tel.: 617-525-1305; Fax: 617-525-1310; E-Mail:
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27
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Balboa MA, Shirai Y, Gaietta G, Ellisman MH, Balsinde J, Dennis EA. Localization of group V phospholipase A2 in caveolin-enriched granules in activated P388D1 macrophage-like cells. J Biol Chem 2003; 278:48059-65. [PMID: 12963740 DOI: 10.1074/jbc.m305904200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In murine P388D1 macrophages, the generation of prostaglandin E2 in response to long term stimulation by lipopolysaccharide involves the action of Group V secreted phospholipase A2 (PLA2), Group IV cytosolic PLA2 (cPLA2), and cyclooxygenase-2 (COX-2). There is an initial activation of cPLA2 that induces expression of Group V PLA2, which in turn induces both the expression of COX-2 and most of the arachidonic acid substrate for COX-2-dependent prostaglandin E2 generation. Because Group V PLA2 is a secreted enzyme, it has been assumed that after cellular stimulation, it must be released to the extracellular medium and re-associates with the outer membrane to release arachidonic acid from phospholipids. In the present study, confocal laser scanning microscopy experiments utilizing both immunofluorescence and green fluorescent protein-labeled Group V PLA2 shows that chronic exposure of the macrophages to lipopolysaccharide results in Group V PLA2 being associated with caveolin-2-containing granules close to the perinuclear region. Heparin, a cell-impermeable complex carbohydrate with high affinity for Group V PLA2, blocks that association, suggesting that the granules are formed by internalization of the Group V sPLA2 previously associated with the outer cellular surface. Localization of Group V PLA2 in perinuclear granules is not observed if the cells are treated with the Group IV PLA2 inhibitor methyl arachidonyl fluorophosphonate, confirming the important role for Group IV PLA2 in the activation process. Cellular staining with antibodies against COX-2 reveals the presence of COX-2-rich granules in close proximity to those containing Group V PLA2. Collectively, these results suggest that encapsulation of Group V PLA2 into granules brings the enzyme to the perinuclear envelope during cell activation where it may be closer to Group IV PLA2 and COX-2 for efficient prostaglandin synthesis.
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Affiliation(s)
- María A Balboa
- Department of Chemistry and Biochemistry, School of Medicine, University of California at San Diego, La Jolla, California 92093-0601, USA
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Abstract
This review focuses on the role of monocytes in the early phase of atherogenesis, before foam cell formation. An emerging consensus underscores the importance of the cellular inflammatory system in atherogenesis. Initiation of the process apparently hinges on accumulating low-density lipoproteins (LDL) undergoing oxidation and glycation, providing stimuli for the release of monocyte attracting chemokines and for the upregulation of endothelial adhesive molecules. These conditions favor monocyte transmigration to the intima, where chemically modified, aggregated, or proteoglycan- or antibody-complexed LDL may be endocytotically internalized via scavenger receptors present on the emergent macrophage surface. The differentiating monocytes in concert with T lymphocytes exert a modulating effect on lipoproteins. These events propagate a series of reactions entailing generation of lipid peroxides and expression of chemokines, adhesion molecules, cytokines, and growth factors, thereby sustaining an ongoing inflammatory process leading ultimately to lesion formation. New data emerging from studies using transgenic animals, notably mice, have provided novel insights into many of the cellular interactions and signaling mechanisms involving monocytes/macrophages in the atherogenic processes. A number of these studies, focusing on mechanisms for monocyte activation and the roles of adhesive molecules, chemokines, cytokines and growth factors, are addressed in this review.
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Affiliation(s)
- Bjarne Osterud
- Department of Biochemistry, Institute of Medical Biology, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
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Abstract
Considerable progress has been made in characterizing the individual participant enzymes and their relative contributions in the generation of eicosanoids, lipid mediators derived from arachidonic acid, such as prostaglandins and leukotrienes. However, the role of individual phospholipase (PL) A(2) enzymes in providing arachidonic acid to the downstream enzymes for eicosanoid generation in biologic processes has not been fully elucidated. In this review, we will provide an overview of the classification of the families of PLA(2) enzymes, their putative mechanisms of action, and their role(s) in eicosanoid generation and inflammation.
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Affiliation(s)
- Bruno L Diaz
- Division of Cell Biology, National Cancer Institute-INCA, R André Cavalcanti 37, Centro, Rio de Janeiro 20231-050, Brazil.
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30
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Granata F, Balestrieri B, Petraroli A, Giannattasio G, Marone G, Triggiani M. Secretory phospholipases A2 as multivalent mediators of inflammatory and allergic disorders. Int Arch Allergy Immunol 2003; 131:153-63. [PMID: 12876405 DOI: 10.1159/000071481] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Phospholipases A(2) (PLA(2)s) are enzymes responsible for mobilization of fatty acids, including arachidonic acid (AA), from phospholipids. These enzymes are classified as high-molecular-weight cytosolic PLA(2)s (cPLA(2)s) and low-molecular-weight secretory PLA(2)s (sPLA(2)s). There is increasing evidence that large quantities of sPLA(2)s are released in the plasma of patients with systemic inflammatory and autoimmune diseases. In addition, high levels of sPLA(2)s can be detected at sites of allergic inflammation including the upper airways of patients with rhinitis and the lower airways of patients with asthma. These extracellular enzymes play an important role in inflammation by releasing AA, which can be subsequently converted to proinflammatory prostaglandins and leukotrienes. Generation of AA mediated by sPLA(2)s occurs through different mechanisms, including (1) the direct hydrolysis of outer cell membrane phospholipids, (2) internalization and transfer of sPLA(2)s to intracellular pools of phospholipids enriched in AA, and (3) activation of cPLA(2)s. In addition, sPLA(2)s induce degranulation and production of cytokines and chemokines from a variety of cells involved in inflammatory and immune responses. These effects are exerted by mechanisms that are independent of the enzymatic activity and are mediated by the interaction of sPLA(2)s with specific or promiscuous membrane receptors. Therefore, sPLA(2)s may have an important role in inflammatory and allergic reactions by activating multiple mechanisms within inflammatory and immune cells, leading to the production of eicosanoids, cytokines and chemokines.
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Affiliation(s)
- Francescopaolo Granata
- Division of Clinical Immunology and Allergy, University of Naples Federico II, Naples, Italy
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31
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Diaz BL, Fujishima H, Sapirstein A, Bonventre JV, Arm JP. Participation of cytosolic phospholipase A2 in eicosanoid generation by mouse bone marrow-derived mast cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 507:41-6. [PMID: 12664562 DOI: 10.1007/978-1-4615-0193-0_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Bruno L Diaz
- Department of Medicine, Harvard Medical School, Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA
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32
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Oh SW, Pae CI, Lee DK, Jones F, Chiang GKS, Kim HO, Moon SH, Cao B, Ogbu C, Jeong KW, Kozu G, Nakanishi H, Kahn M, Chi EY, Henderson WR. Tryptase inhibition blocks airway inflammation in a mouse asthma model. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:1992-2000. [PMID: 11823536 DOI: 10.4049/jimmunol.168.4.1992] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Release of human lung mast cell tryptase may be important in the pathophysiology of asthma. We examined the effect of the reversible, nonelectrophilic tryptase inhibitor MOL 6131 on airway inflammation and hyper-reactivity in a murine model of asthma. MOL 6131 is a potent selective nonpeptide inhibitor of human lung mast cell tryptase based upon a beta-strand template (K(i) = 45 nM) that does not inhibit trypsin (K(i) = 1,061 nM), thrombin (K(i) = 23, 640 nM), or other serine proteases. BALB/c mice after i.p. OVA sensitization (day 0) were challenged intratracheally with OVA on days 8, 15, 18, and 21. MOL 6131, administered days 18-21, blocked the airway inflammatory response to OVA assessed 24 h after the last OVA challenge on day 22; intranasal delivery (10 mg/kg) had a greater anti-inflammatory effect than oral delivery (10 or 25 mg/kg) of MOL 6131. MOL 6131 reduced total cells and eosinophils in bronchoalveolar lavage fluid, airway tissue eosinophilia, goblet cell hyperplasia, mucus secretion, and peribronchial edema and also inhibited the release of IL-4 and IL-13 in bronchoalveolar lavage fluid. However, tryptase inhibition did not alter airway hyper-reactivity to methacholine in vivo. These results support tryptase as a therapeutic target in asthma and indicate that selective tryptase inhibitors can reduce allergic airway inflammation.
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Affiliation(s)
- Se-Woong Oh
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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33
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Ueno N, Murakami M, Tanioka T, Fujimori K, Tanabe T, Urade Y, Kudo I. Coupling between cyclooxygenase, terminal prostanoid synthase, and phospholipase A2. J Biol Chem 2001; 276:34918-27. [PMID: 11418589 DOI: 10.1074/jbc.m100429200] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have recently shown that two distinct prostaglandin (PG) E(2) synthases show preferential functional coupling with upstream cyclooxygenase (COX)-1 and COX-2 in PGE(2) biosynthesis. To investigate whether other lineage-specific PG synthases also show preferential coupling with either COX isozyme, we introduced these enzymes alone or in combination into 293 cells to reconstitute their functional interrelationship. As did the membrane-bound PGE(2) synthase, the perinuclear enzymes thromboxane synthase and PGI(2) synthase generated their respective products via COX-2 in preference to COX-1 in both the -induced immediate and interleukin-1-induced delayed responses. Hematopoietic PGD(2) synthase preferentially used COX-1 and COX-2 in the -induced immediate and interleukin-1-induced delayed PGD(2)-biosynthetic responses, respectively. This enzyme underwent stimulus-dependent translocation from the cytosol to perinuclear compartments, where COX-1 or COX-2 exists. COX selectivity of these lineage-specific PG synthases was also significantly affected by the concentrations of arachidonate, which was added exogenously to the cells or supplied endogenously by the action of cytosolic or secretory phospholipase A(2). Collectively, the efficiency of coupling between COXs and specific PG synthases may be crucially influenced by their spatial and temporal compartmentalization and by the amount of arachidonate supplied by PLA(2)s at a moment when PG production takes place.
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Affiliation(s)
- N Ueno
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Osaka Bioscience Institute CREST, Japan
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34
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Affiliation(s)
- M Murakami
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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35
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Capper EA, Marshall LA. Mammalian phospholipases A(2): mediators of inflammation, proliferation and apoptosis. Prog Lipid Res 2001; 40:167-97. [PMID: 11275266 DOI: 10.1016/s0163-7827(01)00002-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- E A Capper
- SmithKline Beecham Pharmaceuticals, Department of Immunology, Upper Merion, 709 Swedeland Road, King of Prussia, PA 19406, USA.
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36
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Kim KP, Rafter JD, Bittova L, Han SK, Snitko Y, Munoz NM, Leff AR, Cho W. Mechanism of human group V phospholipase A2 (PLA2)-induced leukotriene biosynthesis in human neutrophils. A potential role of heparan sulfate binding in PLA2 internalization and degradation. J Biol Chem 2001; 276:11126-34. [PMID: 11118430 DOI: 10.1074/jbc.m004604200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human group V phospholipase A(2) (hVPLA(2)) has been shown to have high activity to elicit leukotriene production in human neutrophils (Han, S. K., Kim, K. P., Koduri, R., Bittova, L., Munoz, N. M., Leff, A. R., Wilton, D. C., Gelb, M. H., and Cho, W. (1999) J. Biol. Chem. 274, 11881-11888). To determine the mechanism by which hVPLA(2) interacts with cell membranes to induce leukotriene formation, we mutated surface cationic residues and a catalytic residue of hVPLA(2) and measured the interactions of mutants with model membranes, immobilized heparin, and human neutrophils. These studies showed that cationic residues, Lys(7), Lys(11), and Arg(34), constitute a part of the interfacial binding surface of hVPLA(2), which accounts for its moderate preference for anionic membranes. Additionally, hVPLA(2) binds heparin with high affinity and has a well defined heparin-binding site. The site is composed of Arg(100), Lys(101), Lys(107), Arg(108), and Arg(111), and is spatially distinct from its interfacial binding surface. Importantly, the activities of the mutants to hydrolyze cell membrane phospholipids and induce leukotriene biosynthesis, when enzymes were added exogenously to neutrophils, correlated with their activities on phosphatidylcholine membranes but not with their affinities for anionic membranes and heparin. These results indicate that hVPLA(2) acts directly on the outer plasma membranes of neutrophils to release fatty acids and lysophospholipids. Further studies suggest that products of hVPLA(2) hydrolysis trigger the cellular leukotriene production by activating cellular enzymes involved in leukotriene formation. Finally, the temporal and spatial resolution of exogenously added hVPLA(2) and mutants suggests that binding to cell surface heparan sulfate proteoglycans is important for the internalization and clearance of cell surface-bound hVPLA(2).
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Affiliation(s)
- K P Kim
- Department of Chemistry, University of Illinois, Chicago, Illinois 60607, USA
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37
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Downey P, Sapirstein A, O'Leary E, Sun TX, Brown D, Bonventre JV. Renal concentrating defect in mice lacking group IV cytosolic phospholipase A(2). Am J Physiol Renal Physiol 2001; 280:F607-18. [PMID: 11249852 DOI: 10.1152/ajprenal.2001.280.4.f607] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Eicosanoids regulate various cellular functions that are important in physiological and pathophysiological processes. Arachidonic acid is released from membranes by phospholipase A(2) (PLA(2)) activity. Activated macrophages derived from mice lacking the 85-kDa group IV cytosolic PLA(2) (cPLA(2)) have a markedly reduced release of prostaglandin E(2) and leukotrienes B(4) and C(4). Under basal conditions and after furosemide, urinary prostaglandin E(2) excretion is reduced in cPLA(2)-knockout (cPLA(2)(-/-)) mice. Serum creatinine, Na(+), K(+), and Ca(2+) concentrations, glomerular filtration rate, and fractional excretion of Na(+) and K(+) are not different in cPLA(2)(-/-) and cPLA(2)(+/+) mice. Maximal urinary concentration is lower in 48-h water-deprived cPLA(2)(-/-) mice compared with cPLA(2)(+/+) animals (1,934 +/- 324 vs. 3,541 +/- 251 mmol/kgH(2)O). Plasma osmolality is higher (337 +/- 5 vs. 319 +/- 3 mmol/kgH(2)O) in cPLA(2)(-/-) mice that lose a greater percentage of their body weight (20 +/- 2 vs. 13 +/- 1%) compared with cPLA(2)(+/+) mice after water deprivation. Vasopressin does not correct the concentrating defect. There is progressive reduction in urinary osmolality with age in cPLA(2)(-/-) mice. Membrane-associated aquaporin-1 (AQP1) expression, identified by immunocytochemical techniques, is reduced markedly in proximal tubules of older cPLA(2)(-/-) animals but is normal in thin descending limbs. However, Western blot analysis of kidney cortical samples revealed an equivalent AQP1 signal intensity in cPLA(2)(+/+) and cPLA(2)(-/-) animals. Young cPLA(2)(-/-) mice have normal proximal tubule AQP1 staining. Collecting duct AQP2, -3, and -4 were normally expressed in the cPLA(2)(-/-) mice. Thus mice lacking cPLA(2) develop an age-related defect in renal concentration that may be related to abnormal trafficking and/or folding of AQP1 in the proximal tubule, implicating cPLA(2) in these processes.
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Affiliation(s)
- P Downey
- Medical and Anesthesia Services, Massachusetts General Hospital, Charlestown, 02129, USA
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38
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Hong KH, Bonventre JC, O'Leary E, Bonventre JV, Lander ES. Deletion of cytosolic phospholipase A(2) suppresses Apc(Min)-induced tumorigenesis. Proc Natl Acad Sci U S A 2001; 98:3935-9. [PMID: 11274413 PMCID: PMC31157 DOI: 10.1073/pnas.051635898] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/30/2000] [Indexed: 12/29/2022] Open
Abstract
Although nonsteroidal antiinflammatory drugs (NSAIDs) show great promise as therapies for colon cancer, a dispute remains regarding their mechanism of action. NSAIDs are known to inhibit cyclooxygenase (COX) enzymes, which convert arachidonic acid (AA) to prostaglandins (PGs). Therefore, NSAIDs may suppress tumorigenesis by inhibiting PG synthesis. However, various experimental studies have suggested the possibility of PG-independent mechanisms. Notably, disruption of the mouse group IIA secretory phospholipase A(2) locus (Pla2g2a), a potential source of AA for COX-2, increases tumor number despite the fact that the mutation has been predicted to decrease PG production. Some authors have attempted to reconcile the results by suggesting that the level of the precursor (AA), not the products (PGs), is the critical factor. To clarify the role of AA in tumorigenesis, we have examined the effect of deleting the group IV cytosolic phospholipase A(2) (cPLA(2)) locus (Pla2g4). We report that Apc(Min/+), cPLA(2)(-/-) mice show an 83% reduction in tumor number in the small intestine compared with littermates with genotypes Apc(Min/+), cPLA(2)(+/-) and Apc(Min/+), cPLA(2)(+/+). This tumor phenotype parallels that of COX-2 knockout mice, suggesting that cPLA(2) is the predominant source of AA for COX-2 in the intestine. The protective effect of cPLA(2) deletion is thus most likely attributed to a decrease in the AA supply to COX-2 and a resultant decrease in PG synthesis. The tumorigenic effect of sPLA(2) mutations is likely to be through a completely different pathway.
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Affiliation(s)
- K H Hong
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
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39
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Abstract
The prostaglandin endoperoxide H synthases-1 and 2 (PGHS-1 and PGHS-2; also cyclooxygenases-1 and 2, COX-1 and COX-2) catalyze the committed step in prostaglandin synthesis. PGHS-1 and 2 are of particular interest because they are the major targets of nonsteroidal anti-inflammatory drugs (NSAIDs) including aspirin, ibuprofen, and the new COX-2 inhibitors. Inhibition of the PGHSs with NSAIDs acutely reduces inflammation, pain, and fever, and long-term use of these drugs reduces fatal thrombotic events, as well as the development of colon cancer and Alzheimer's disease. In this review, we examine how the structures of these enzymes relate mechanistically to cyclooxygenase and peroxidase catalysis, and how differences in the structure of PGHS-2 confer on this isozyme differential sensitivity to COX-2 inhibitors. We further examine the evidence for independent signaling by PGHS-1 and PGHS-2, and the complex mechanisms for regulation of PGHS-2 gene expression.
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Affiliation(s)
- W L Smith
- Department of Biochemistry, Michigan State University, East Lansing, MI 48824, USA.
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40
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Saiga A, Morioka Y, Ono T, Nakano K, Ishimoto Y, Arita H, Hanasaki K. Group X secretory phospholipase A(2) induces potent productions of various lipid mediators in mouse peritoneal macrophages. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1530:67-76. [PMID: 11341959 DOI: 10.1016/s1388-1981(00)00167-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown the expression of group X secretory phospholipase A(2) (sPLA(2)-X) in mouse splenic macrophages and its powerful potency for releasing fatty acids from various intact cell membranes. Here, we examined the potency of sPLA(2)-X in the production of lipid mediators in murine peritoneal macrophages. Mouse sPLA(2)-X was found to induce a marked release of fatty acids including arachidonic acid and linoleic acid, which contrasted with little, if any, release by the action of group IB and IIA sPLA(2)s. In resting macrophages, sPLA(2)-X elicited a modest production of prostaglandin E(2) and thromboxane A(2). After the induction of cyclooxygenase-2 (COX-2) by pretreatment with lipopolysaccharide, a dramatic increase in the production of these eicosanoids was observed in sPLA(2)-X-treated macrophages, which was completely blocked by the addition of either the specific sPLA(2) inhibitor indoxam or the COX inhibitor indomethacin. In accordance with its higher hydrolyzing activity toward phosphatidylcholine, mouse sPLA(2)-X induced a potent production of lysophosphatidylcholine. These findings strongly suggest that sPLA(2)-X plays a critical role in the production of various lipid mediators from macrophages. These events might be relevant to the progression of various pathological states, including chronic inflammation and atherosclerosis.
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Affiliation(s)
- A Saiga
- Shionogi Research Laboratories, Shionogi&Co., Ltd., 12-4 Sagisu, 5-Chome, Fukushima-ku, 553-0002, Osaka, Japan
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41
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Fonteh AN, LaPorte T, Swan D, McAlexander MA. A decrease in remodeling accounts for the accumulation of arachidonic acid in murine mast cells undergoing apoptosis. J Biol Chem 2001; 276:1439-49. [PMID: 11022038 DOI: 10.1074/jbc.m006551200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The goal of this study was to examine arachidonic acid (AA) metabolism by murine bone marrow-derived mast cells (BMMC) during apoptosis induced by cytokine depletion. BMMC deprived of cytokines for 12-48 h displayed apoptotic characteristics. During apoptosis, levels of AA, but not other unsaturated fatty acids, correlated with the percentage of apoptotic cells. A decrease in both cytosolic phospholipase A(2) expression and activity indicated that cytosolic phospholipase A(2) did not account for AA mobilization during apoptosis. Free AA accumulation is also unlikely to be due to decreases in 5-lipoxygenase and/or cyclooxygenase activities, since BMMC undergoing apoptosis produced similar amounts of leukotriene B(4) and significantly greater amounts of PGD(2) than control cells. Arachidonoyl-CoA synthetase and CoA-dependent transferase activities responsible for incorporating AA into phospholipids were not altered during apoptosis. However, there was an increase in arachidonate in phosphatidylcholine (PC) and neutral lipids concomitant with a 40.7 +/- 8.1% decrease in arachidonate content in phosphatidylethanolamine (PE), suggesting a diminished capacity of mast cells to remodel arachidonate from PC to PE pools. Further evidence of a decrease in AA remodeling was shown by a significant decrease in microsomal CoA-independent transacylase activity. Levels of lyso-PC and lyso-PE were not altered in cells undergoing apoptosis, suggesting that the accumulation of lysophospholipids did not account for the decrease in CoA-independent transacylase activity or the induction of apoptosis. Together, these data suggest that the mole quantities of free AA closely correlated with apoptosis and that the accumulation of AA in BMMC during apoptosis was mediated by a decreased capacity of these cells to remodel AA from PC to PE.
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Affiliation(s)
- A N Fonteh
- Department of Internal Medicine, Pulmonary and Critical Care Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27154, USA.
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42
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Thomas B, Berenbaum F, Humbert L, Bian H, Béréziat G, Crofford L, Olivier JL. Critical role of C/EBPdelta and C/EBPbeta factors in the stimulation of the cyclooxygenase-2 gene transcription by interleukin-1beta in articular chondrocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:6798-809. [PMID: 11082190 DOI: 10.1046/j.1432-1033.2000.01778.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The activity of the [-831; +103] promoter of the human cyclooxygenase-2 gene in cultured rabbit chondrocytes is stimulated 2.9 +/- 0.3-fold by interleukin-1beta and this stimulation depends on [-132; -124] C/EBP binding-and [-223; -214] NF-kappaB binding-sites. The C/EBPbeta and C/EBPdelta factors bind to the [-132; -124] sequence. The [-61; -53] sequence is also recognized by C/EBPbeta and C/EBPdelta as well as USF. Mutation of the whole [-61; -53] sequence abolished the stimulation of transcription but single mutations of the C/EBP or USF site did not alter the activity of the promoter, suggesting that the factors bound to the proximal [-61; -53] sequence interact with different members of the general transcription machinery. The [-223; -214] site binds only the p50/p50 homodimer and a non-rel-related protein, but not the transcriptionally active heterodimer p50/p65. The p50/p50 homodimer could interact with the C/EBP family members bound to the [-132; -124] sequence for full stimulation of the COX-2 transcription by interleukin-1beta in chondrocytes. By contrast, the [-448; -449] sequence binds with a low affinity both the p50/p50 homodimeric and p50/p65 heterodimeric forms of NF-kappaB but has no role in the regulation of the human COX-2 promoter in chondrocytes.
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Affiliation(s)
- B Thomas
- UPRES-A CNRS 7079, Université Pierre et Marie Curie, Paris, France
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43
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Takaku K, Sonoshita M, Sasaki N, Uozumi N, Doi Y, Shimizu T, Taketo MM. Suppression of Intestinal Polyposis inApc Δ716 Knockout Mice by an Additional Mutation in the Cytosolic Phospholipase A2Gene. J Biol Chem 2000. [DOI: 10.1074/jbc.c000586200] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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44
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Sapirstein A, Bonventre JV. Specific physiological roles of cytosolic phospholipase A(2) as defined by gene knockouts. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:139-48. [PMID: 11080683 DOI: 10.1016/s1388-1981(00)00116-5] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The cytosolic 85 kDa phospholipase A(2) (cPLA(2)) is a unique member of the phospholipase A(2) (PLA(2)) superfamily. Because PLA(2) activity and eicosanoid production are important in normal and pathophysiological states we and the laboratory of Shimizu created a mouse deficient in cPLA(2) (cPLA(2)(-/-) mouse). cPLA(2)(-/-) mice develop normally but the females have severe reproductive defects. cPLA(2)(-/-) mice suffer smaller infarcts and fewer neurological deficits after transient occlusion of the middle cerebral artery and have less injury after administration of a dopaminergic selective neurotoxin. cPLA(2)(-/-) mice have a more rapid recovery from allergen-induced bronchoconstriction and have no airway hyperresponsiveness. Peritoneal macrophages from cPLA(2)(-/-) mice fail to produce prostaglandins, leukotriene B(4) and cysteinyl leukotrienes after stimulation. Bone marrow-derived mast cells from cPLA(2)(-/-) mice fail to produce eicosanoids in either immediate or delayed phase responses. Thus the cPLA(2) knockout mouse has revealed important roles of cPLA(2) in normal fertility, generation of eicosanoids from inflammatory cells, brain injuries and allergic responses. Furthermore the cPLA(2)(-/-) mouse reveals that the many other forms of PLA(2) cannot replace many functions of cPLA(2). The importance of cPLA(2) in inflammation and tissue injury suggests that pharmacological targeting of this enzyme may have important therapeutic benefits.
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Affiliation(s)
- A Sapirstein
- Department of Anesthesiology and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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45
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Cho W. Structure, function, and regulation of group V phospholipase A(2). BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:48-58. [PMID: 11080676 DOI: 10.1016/s1388-1981(00)00109-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The hydrolysis of membrane phospholipid by phospholipase A(2) (PLA(2)) is a key step in the production of inflammatory eicosanoids. Recent cell studies have shown that secretory group V PLA(2) (gVPLA(2)) is involved in agonist-induced eicosanoid biosynthesis in mouse P388D1 cell line, mast cells, and transfected HEK 293 cells. gVPLA(2) is homologous to other group II PLA(2) family members but has distinctive enzymatic properties, including its activity to effectively hydrolyze phosphatidylcholine (PC) vesicles and the outer plasma membrane of mammalian cells. Mutational studies showed that gVPLA(2) has a unique structure that allows effective binding to PC membranes and efficient catalysis of an active-site-bound PC substrate. Thanks to this unique structure and activity, exogenously added gVPLA(2) can induce the eicosanoid biosynthesis in unstimulated inflammatory cells, including human neutrophils and eosinophils, suggesting that it might be able to trigger inflammatory responses under certain physiological conditions. Extensive structure-function and cell studies showed that gVPLA(2) could act directly on the outer plasma membranes of neutrophils and eosinophils. The release of fatty acids and lysophospholipids from the cell surfaces induces the translocation and activation of cytosolic PLA(2) and 5-lipoxygenase, resulting in the leukotriene synthesis. In case of neutrophils, induction of leukotriene B(4) synthesis by gVPLA(2) leads to the phosphorylation of cytosolic PLA(2) by a leukotriene B(4) receptor and MAP kinase-mediated mechanism. Finally, heparan sulfate proteoglycans in neutrophils appear to play a role of internalizing and degrading the cell surface-bound gVPLA(2) to protect the cells from extensive lipolytic damage.
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Affiliation(s)
- W Cho
- Department of Chemistry (M/C 111), University of Illinois at Chicago, 60607-7061, USA.
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46
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Yedgar S, Lichtenberg D, Schnitzer E. Inhibition of phospholipase A(2) as a therapeutic target. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:182-7. [PMID: 11080687 DOI: 10.1016/s1388-1981(00)00120-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hydrolysis of cell membrane phospholipids by phospholipase A(2) (PLA(2)) leads to the production of numerous lipid mediators of diverse pathological conditions, mainly inflammatory diseases. These include lysophospholipids and their derivatives, and arachidonic acid and its derivatives (the eicosanoids). Both these groups of mediators are produced predominantly by the secretory PLA(2)s (sPLA(2)s) which hydrolyze the phospholipids of the cell surface membrane. Protection of cell membrane from these 'inflammatory enzymes' can therefore be used for the treatment of inflammatory processes. A prototype of cell-impermeable PLA(2) inhibitors, which protect the cell membrane from different sPLA(2)s without affecting vital phospholipid metabolism, is presented and discussed in the present review.
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Affiliation(s)
- S Yedgar
- Department of Biochemistry, Hebrew University-hadassah Medical School, Jerusalem, Israel
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47
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Enomoto A, Murakami M, Valentin E, Lambeau G, Gelb MH, Kudo I. Redundant and segregated functions of granule-associated heparin-binding group II subfamily of secretory phospholipases A2 in the regulation of degranulation and prostaglandin D2 synthesis in mast cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:4007-14. [PMID: 11034411 DOI: 10.4049/jimmunol.165.7.4007] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We herein demonstrate that mast cells express all known members of the group II subfamily of secretory phospholipase A2 (sPLA2) isozymes, and those having heparin affinity markedly enhance the exocytotic response. Rat mastocytoma RBL-2H3 cells transfected with heparin-binding (sPLA2-IIA, -V, and -IID), but not heparin-nonbinding (sPLA2-IIC), enzymes released more granule-associated markers (beta-hexosaminidase and histamine) than mock- or cytosolic PLA2alpha (cPLA2alpha)-transfected cells after stimulation with IgE and Ag. Site-directed mutagenesis of sPLA2-IIA and -V revealed that both the catalytic and heparin-binding domains are essential for this function. Confocal laser and electron microscopic analyses revealed that sPLA2-IIA, which was stored in secretory granules in unstimulated cells, accumulated on the membranous sites where fusion between the plasma membrane and granule membranes occurred in activated cells. These results suggest that the heparin-binding sPLA2s bind to the perigranular membranes through their heparin-binding domain, and lysophospholipids produced in situ by their enzymatic action may facilitate the ongoing membrane fusion. In contrast to the redundant role of sPLA2-IIA, -IID, and -V in the regulation of degranulation, only sPLA2-V had the ability to markedly augment IgE/Ag-stimulated immediate PGD2 production, which reached a level comparable to that elicited by cPLA2alpha. The latter observation reveals an unexplored functional segregation among the three related isozymes expressed in the same cell population.
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Affiliation(s)
- A Enomoto
- Department of Health Chemistry, Showa University School of Pharmaceutical Sciences, Tokyo, Japan
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48
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Fonteh AN, Atsumi G, LaPorte T, Chilton FH. Secretory phospholipase A2 receptor-mediated activation of cytosolic phospholipase A2 in murine bone marrow-derived mast cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2773-82. [PMID: 10946309 DOI: 10.4049/jimmunol.165.5.2773] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The current study examined the signal transduction steps involved in the selective release of arachidonic acid (AA) induced by the addition of secretory phospholipase A2 (sPLA2) isotypes to bone marrow-derived mast cells (BMMC). Overexpression of sPLA2 receptors caused a marked increase in AA and PGD2 release after stimulation of BMMC, implicating sPLA2 receptors in this process. The hypothesis that the release of AA by sPLA2 involved activation of cytosolic PLA2 (cPLA2) was next tested. Addition of group IB PLA2 to BMMC caused a transient increase in cPLA2 activity and translocation of this activity to membrane fractions. Western analyses revealed that these changes in cPLA2 were accompanied by a time-dependent gel shift of cPLA2 induced by phosphorylation of cPLA2 at various sites. A noncatalytic ligand of the sPLA2 receptor, p-amino-phenyl-alpha-D-mannopyranoside BSA, also induced an increase in cPLA2 activity in BMMC. sPLA2 receptor ligands induced the phosphorylation of p44/p42 mitogen-activated protein kinase. Additionally, an inhibitor of p44/p42 mitogen-activated protein kinase (PD98059) significantly inhibited sPLA2-induced cPLA2 activation and AA release. sPLA2 receptor ligands also increased Ras activation while an inhibitor of tyrosine phosphorylation (herbimycin) inhibited the increase in cPLA2 activation and AA release. Addition of partially purified sPLA2 from BMMC enhanced cPLA2 activity and AA release. Similarly, overexpression of mouse groups IIA or V PLA2 in BMMC induced an increase in AA release. These data suggest that sPLA2 mediate the selective release of AA by binding to cell surface receptors and then inducing signal transduction events that lead to cPLA2 activation.
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Affiliation(s)
- A N Fonteh
- Departments of Internal Medicine, Pulmonary and Critical Care Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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Massaad C, Paradon M, Jacques C, Salvat C, Bereziat G, Berenbaum F, Olivier JL. Induction of secreted type IIA phospholipase A2 gene transcription by interleukin-1beta. Role of C/EBP factors. J Biol Chem 2000; 275:22686-94. [PMID: 10791956 DOI: 10.1074/jbc.m001250200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Secreted type IIA phospholipase A(2), which is involved in arachidonic acid release, is abundantly produced by chondrocytes and secreted in the synovial fluids of patients affected by rheumatoid arthritis. Transfection experiments showed that interleukin-1beta stimulates the phospholipase A(2) [-1614; +20] promoter activity by 6-7-fold and that the [-210; -176] fragment is critical for this stimulation. CAAT enhancer-binding protein (C/EBP) beta and C/EBPdelta transcription factors bind to this element as shown by bandshift experiments. Interleukin-1beta increased the levels of C/EBPdelta mRNA as soon as 2 h and up to 24 h without affecting those of C/EBPbeta. Higher amounts of C/EBPdelta proteins correlate with the stimulation of C/EBPdelta mRNA. Mutations or 5' deletions in the upstream [-247; -210] region reduced by 2-fold the basal and interleukin-1beta-stimulated transcription activities. Two types of factors bind to overlapping sequences on this fragment: NF1-like proteins and the glucocorticoid receptor. The glucocorticoid receptor is responsible for a moderate stimulation of the promoter activity by dexamethasone and may interact with C/EBP factors to achieve a full transcription activity in basal conditions and in the presence of interleukin-1beta. A [-114; -85] proximal regulatory element forms three complexes in bandshift experiments, the slowest mobility one involving the Sp1 zinc finger factor. Mutation of this sequence reduced to 2-fold the stimulation of the promoter activity by interleukin-1beta or the C/EBP factors. Induction of the transcription of secreted type IIA phospholipase A(2) gene by interleukin-1beta in chondrocytes absolutely requires C/EBPbeta and C/EBPdelta factors but does not involve NF-kappaB.
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Affiliation(s)
- C Massaad
- UPRES-A CNRS 7079, UFR Saint Antoine, UPRES-A CNRS 7079, Université Pierre et Marie Curie, 7 quai Saint Bernard 75252 Paris Cedex 05, France
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Balsinde J, Balboa MA, Dennis EA. Identification of a third pathway for arachidonic acid mobilization and prostaglandin production in activated P388D1 macrophage-like cells. J Biol Chem 2000; 275:22544-9. [PMID: 10811815 DOI: 10.1074/jbc.m910163199] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Previous studies have demonstrated that P388D(1) macrophages are able to mobilize arachidonic acid (AA) and synthesize prostaglandins in two temporally distinct phases. The first phase is triggered by platelet-activating factor within minutes, but needs the cells to be previously exposed to bacterial lipopolysaccharide (LPS) for periods up to 1 h. It is thus a primed immediate phase. The second, delayed phase occurs in response to LPS alone over long incubation periods spanning several hours. Strikingly, the effector enzymes involved in both of these phases are the same, namely the cytosolic group IV phospholipase A(2) (cPLA(2)), the secretory group V phospholipase A(2), and cyclooxygenase-2, although the regulatory mechanisms differ. Here we report that P388D(1) macrophages mobilize AA and produce prostaglandins in response to zymosan particles in a manner that is clearly different from the two described above. Zymosan triggers an immediate AA mobilization response from the macrophages that neither involves the group v phospholipase A(2) nor requires the cells to be primed by LPS. The group VI Ca(2+)-independent phospholipase A(2) is also not involved. Zymosan appears to signal exclusively through activation of the cPLA(2), which is coupled to the cyclooxygenase-2. These results define a secretory PLA(2)-independent pathway for AA mobilization in the P388D(1) macrophages, and demonstrate that, under certain experimental settings, stimulation of the cPLA(2) is sufficient to generate a prostaglandin biosynthetic response in the P388D(1) macrophages.
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Affiliation(s)
- J Balsinde
- Department of Chemistry and Biochemistry, Revelle College and School of Medicine, University of California at San Diego, La Jolla, California 92093-0601, USA.
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