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Abstract
The secretory phospholipase A2 (sPLA2) group of secreted enzymes hydrolyze phospholipids and lead to the production of multiple biologically active lipid mediators. sPLA2s and their products (e.g., eicosanoids) play a significant role in the pathophysiology of various inflammatory diseases, including life-threatening lung disorders such as acute lung injury (ALI) and the Acute Respiratory Distress Syndrome (ARDS). The ALI/ARDS spectrum of severe inflammatory conditions is caused by direct (such as bacterial or viral pneumonia) or indirect insults (sepsis) that are associated with high morbidity and mortality. Several sPLA2 isoforms are upregulated in patients with ARDS as well as in multiple ALI preclinical models, and individual sPLA2s exert unique roles in regulating ALI pathophysiology. This brief review will summarize the contributions of specific sPLA2 isoforms as markers and mediators in ALI, supporting a potential therapeutic role for targeting them in ARDS.
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Affiliation(s)
- Eleftheria Letsiou
- Division of Pulmonary, Critical Care, Sleep and Allergy, University of Illinois at Chicago, Chicago, IL, USA
| | - Yu Maw Htwe
- Division of Pulmonary, Critical Care, Sleep and Allergy, University of Illinois at Chicago, Chicago, IL, USA
| | - Steven M Dudek
- Division of Pulmonary, Critical Care, Sleep and Allergy, University of Illinois at Chicago, Chicago, IL, USA.
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2
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Hayashi D, Mouchlis VD, Dennis EA. Omega-3 versus Omega-6 fatty acid availability is controlled by hydrophobic site geometries of phospholipase A 2s. J Lipid Res 2021; 62:100113. [PMID: 34474084 PMCID: PMC8551542 DOI: 10.1016/j.jlr.2021.100113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 11/12/2022] Open
Abstract
Human phospholipase A2s (PLA2) constitute a superfamily of enzymes that hydrolyze the sn-2 acyl-chain of glycerophospholipids, producing lysophospholipids and free fatty acids. Each PLA2 enzyme type contributes to specific biological functions based on its expression, subcellular localization, and substrate specificity. Among the PLA2 superfamily, the cytosolic cPLA2 enzymes, calcium-independent iPLA2 enzymes, and secreted sPLA2 enzymes are implicated in many diseases, but a central issue is the preference for double-bond positions in polyunsaturated fatty acids (PUFAs) occupying the sn-2 position of membrane phospholipids. We demonstrate that each PLA2 has a unique preference between the specific omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the omega-6 arachidonic acid (AA), which are the precursors of most proinflammatory and anti-inflammatory or resolving eicosanoids and related oxylipins. Surprisingly, we discovered that human cPLA2 selectively prefers AA, whereas iPLA2 prefers EPA, and sPLA2 prefers DHA as substrate. We determined the optimal binding of each phospholipid substrate in the active site of each PLA2 to explain these specificities. To investigate this, we utilized recently developed lipidomics-based LC-MS/MS and GC/MS assays to determine the sn-2 acyl chain specificity in mixtures of phospholipids. We performed μs timescale molecular dynamics (MD) simulations to reveal unique active site properties, especially how the precise hydrophobic cavity accommodation of the sn-2 acyl chain contributes to the stability of substrate binding and the specificity of each PLA2 for AA, EPA, or DHA. This study provides the first comprehensive picture of the unique substrate selectivity of each PLA2 for omega-3 and omega-6 fatty acids.
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Affiliation(s)
- Daiki Hayashi
- Department of Chemistry and Biochemistry and Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Varnavas D Mouchlis
- Department of Chemistry and Biochemistry and Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Edward A Dennis
- Department of Chemistry and Biochemistry and Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
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3
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Knuplez E, Sturm EM, Marsche G. Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids, Polyunsaturated Fatty Acids and Eicosanoids. Int J Mol Sci 2021; 22:4356. [PMID: 33919453 PMCID: PMC8122506 DOI: 10.3390/ijms22094356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
Eosinophils are important effector cells involved in allergic inflammation. When stimulated, eosinophils release a variety of mediators initiating, propagating, and maintaining local inflammation. Both, the activity and concentration of secreted and cytosolic phospholipases (PLAs) are increased in allergic inflammation, promoting the cleavage of phospholipids and thus the production of reactive lipid mediators. Eosinophils express high levels of secreted phospholipase A2 compared to other leukocytes, indicating their direct involvement in the production of lipid mediators during allergic inflammation. On the other side, eosinophils have also been recognized as crucial mediators with regulatory and homeostatic roles in local immunity and repair. Thus, targeting the complex network of lipid mediators offer a unique opportunity to target the over-activation and 'pro-inflammatory' phenotype of eosinophils without compromising the survival and functions of tissue-resident and homeostatic eosinophils. Here we provide a comprehensive overview of the critical role of phospholipase-derived lipid mediators in modulating eosinophil activity in health and disease. We focus on lysophospholipids, polyunsaturated fatty acids, and eicosanoids with exciting new perspectives for future drug development.
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Affiliation(s)
| | | | - Gunther Marsche
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, 8010 Graz, Austria; (E.K.); (E.M.S.)
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4
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Cysteinyl leukotriene metabolism of human eosinophils in allergic disease. Allergol Int 2020; 69:28-34. [PMID: 31248811 DOI: 10.1016/j.alit.2019.06.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/09/2019] [Accepted: 05/23/2019] [Indexed: 01/14/2023] Open
Abstract
Eosinophils are multifaceted immune cells with diverse functions that enhance allergic inflammation. Cysteinyl leukotrienes (cys-LTs), mainly synthesized in eosinophils, are a class of inflammatory lipid mediators produced via multiple enzymatic reactions from arachidonic acid. Multiple clinical studies have reported dysregulated fatty acid metabolism in severe asthma and aspirin-exacerbated respiratory diseases. Therefore, understanding the mechanism responsible for this metabolic abnormality has attracted a lot of attention. In eosinophils, various stimuli (including cytokines, chemokines, and pathogen-derived factors) prime and/or induce leukotriene generation and secretion. Cell-cell interactions with component cells (endothelial cells, epithelial cells, fibroblasts) also enhance this machinery to augment allergic responses. Nasal polyp-derived eosinophils from patients with eosinophilic rhinosinusitis present a characteristic fatty acid metabolism with selectively higher production of leukotriene D4. Interestingly, type 2 cytokines and microbiome components might be responsible for this metabolic change with altered enzyme expression. Here, we review the regulation of fatty acid metabolism, especially cys-LT metabolism, in human eosinophils toward allergic inflammatory status.
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Degradation of group V secretory phospholipase A 2 in lung endothelium is mediated by autophagy. Microvasc Res 2019; 129:103954. [PMID: 31730773 DOI: 10.1016/j.mvr.2019.103954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/18/2019] [Accepted: 11/10/2019] [Indexed: 02/07/2023]
Abstract
Group V secretory phospholipase A2 (gVPLA2) is a potent inflammatory mediator in mammalian tissues that hydrolyzes phospholipids and initiates eicosanoid biosynthesis. Previous work has demonstrated that multiple inflammatory stimuli induce its expression and secretion in several cell types, including the lung endothelium. However, little is known about the mechanism(s) by which gVPLA2 inflammatory signaling is subsequently downregulated. Therefore, in this study we characterized potential clearance mechanisms for gVPLA2 in lung endothelial cells (EC). We observed that exogenous gVPLA2 is taken up rapidly by nutrient-starved human pulmonary artery EC (HPAEC) in vitro, and its cellular expression subsequently is reduced over several hours. In parallel experiments performed in pulmonary vascular EC isolated from mice genetically deficient in gVPLA2, the degradation of exogenously applied gVPLA2 occurs in a qualitatively similar fashion. This degradation is significantly attenuated in EC treated with ammonium chloride or chloroquine, which are lysosomal inhibitors that block autophagic flux. In contrast, the proteasomal inhibitor MG132 fails to prevent the clearance of gVPLA2. Both immunofluorescence microscopy and proximity ligation assay demonstrate the co-localization of LC3 and gVPLA2 during this process, indicating the association of gVPLA2 with autophagosomes. Nutrient starvation, a known inducer of autophagy, is sufficient to stimulate gVPLA2 degradation. These results suggest that a lysosome-mediated autophagy pathway contributes to gVPLA2 clearance from lung EC. These novel observations advance our understanding of the mechanism by which this key inflammatory enzyme is downregulated in the lung vasculature.
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Samuchiwal SK, Balestrieri B. Harmful and protective roles of group V phospholipase A 2: Current perspectives and future directions. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:819-826. [PMID: 30308324 DOI: 10.1016/j.bbalip.2018.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 09/27/2018] [Accepted: 10/01/2018] [Indexed: 12/17/2022]
Abstract
Group V Phospholipase A2 (Pla2g5) is a member of the PLA2 family of lipid-generating enzymes. It is expressed in immune and non-immune cell types and is inducible during several pathologic conditions serving context-specific functions. In this review, we recapitulate the protective and detrimental functions of Pla2g5 investigated through preclinical and translational approaches. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.
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Affiliation(s)
- Sachin K Samuchiwal
- Department of Medicine, Harvard Medical School, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Barbara Balestrieri
- 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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Montenegro-Burke JR, Sutton JA, Rogers LM, Milne GL, McLean JA, Aronoff DM. Lipid profiling of polarized human monocyte-derived macrophages. Prostaglandins Other Lipid Mediat 2016; 127:1-8. [PMID: 27871801 PMCID: PMC6053630 DOI: 10.1016/j.prostaglandins.2016.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/11/2016] [Indexed: 12/31/2022]
Abstract
The highly orchestrated transcriptional and metabolic reprogramming during activation drastically transforms the main functions and physiology of human macrophages across the polarization spectrum. Lipids, for example, can modify protein function by acting remotely as signaling molecules but also locally by altering the physical properties of cellular membranes. These changes play key roles in the functions of highly plastic immune cells due to their involvement in inflammation, immune responses, phagocytosis and wound healing processes. We report an analysis of major membrane lipids of distinct phenotypes of resting (M0), classically activated (M1), alternatively activated (M2a) and deactivated (M2c) human monocyte derived macrophages from different donors. Samples were subjected to supercritical fluid chromatography-ion mobility-mass spectrometry analysis, which allowed separations based on lipid class, facilitating the profiling of their fatty acid composition. Different levels of arachidonic acid mobilization as well as other fatty acid changes were observed for different lipid classes in the distinct polarization phenotypes, suggesting the activation of highly orchestrated and specific enzymatic processes in the biosynthesis of lipid signaling molecules and cell membrane remodeling. Thromboxane A2 production appeared to be a specific marker of M1 polarization. These alterations to the global composition of lipid bi-layer membranes in the cell provide a potential methodology for the definition and determination of cellular and tissue activation states.
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Affiliation(s)
- J Rafael Montenegro-Burke
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37235, USA; Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, 37235, USA; Center for Innovative Technology, Vanderbilt University, Nashville, TN 37235, USA
| | - Jessica A Sutton
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA; Department of Microbiology and Immunology, Meharry Medical College School of Medicine, Nashville, TN, 37208, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Lisa M Rogers
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Ginger L Milne
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - John A McLean
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37235, USA; Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, 37235, USA; Center for Innovative Technology, Vanderbilt University, Nashville, TN 37235, USA
| | - David M Aronoff
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN, 37235, USA; Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA; Department of Microbiology and Immunology, Meharry Medical College School of Medicine, Nashville, TN, 37208, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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Nakamura H, Wakita S, Yasufuku K, Makiyama T, Waraya M, Hashimoto N, Murayama T. Sphingomyelin Regulates the Activity of Secretory Phospholipase A2in the Plasma Membrane. J Cell Biochem 2015; 116:1898-907. [DOI: 10.1002/jcb.25145] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/20/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Hiroyuki Nakamura
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Shigeo Wakita
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Kana Yasufuku
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Tomohiko Makiyama
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Misa Waraya
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Naohiro Hashimoto
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Toshihiko Murayama
- Laboratory of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
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Endogenous secreted phospholipase A2 group X regulates cysteinyl leukotrienes synthesis by human eosinophils. J Allergy Clin Immunol 2015; 137:268-277.e8. [PMID: 26139511 DOI: 10.1016/j.jaci.2015.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 04/23/2015] [Accepted: 05/04/2015] [Indexed: 02/05/2023]
Abstract
BACKGROUND Phospholipase A2s mediate the rate-limiting step in the formation of eicosanoids such as cysteinyl leukotrienes (CysLTs). Group IVA cytosolic PLA2α (cPLA2α) is thought to be the dominant PLA2 in eosinophils; however, eosinophils also have secreted PLA2 (sPLA2) activity that has not been fully defined. OBJECTIVES To examine the expression of sPLA2 group X (sPLA2-X) in eosinophils, the participation of sPLA2-X in the formation of CysLTs, and the mechanism by which sPLA2-X initiates the synthesis of CysLTs in eosinophils. METHODS Peripheral blood eosinophils were obtained from volunteers with asthma and/or allergy. A rabbit polyclonal anti-sPLA2-X antibody identified sPLA2-X by Western blot. We used confocal microscopy to colocalize the sPLA2-X to intracellular structures. An inhibitor of sPLA2-X (ROC-0929) that does not inhibit other mammalian sPLA2s, as well as inhibitors of the mitogen-activated kinase cascade (MAPK) and cPLA2α, was used to examine the mechanism of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-mediated formation of CysLT. RESULTS Eosinophils express the mammalian sPLA2-X gene (PLA2G10). The sPLA2-X protein is located in the endoplasmic reticulum, golgi, and granules of eosinophils and moves to the granules and lipid bodies during fMLP-mediated activation. Selective sPLA2-X inhibition attenuated the fMLP-mediated release of arachidonic acid and CysLT formation by eosinophils. Inhibitors of p38, extracellular-signal-regulated kinases 1/2 (p44/42 MAPK), c-Jun N-terminal kinase, and cPLA2α also attenuated the fMLP-mediated formation of CysLT. The sPLA2-X inhibitor reduced the phosphorylation of p38 and extracellular-signal-regulated kinases 1/2 (p44/42 MAPK) as well as cPLA2α during cellular activation, indicating that sPLA2-X is involved in activating the MAPK cascade leading to the formation of CysLT via cPLA2α. We further demonstrate that sPLA2-X is activated before secretion from the cell during activation. Short-term priming with IL-13 and TNF/IL-1β increased the expression of PLA2G10 by eosinophils. CONCLUSIONS These results demonstrate that sPLA2-X plays a significant role in the formation of CysLTs by human eosinophils. The predominant role of the enzyme is the regulation of MAPK activation that leads to the phosphorylation of cPLA2α. The sPLA2-X protein is regulated by proteolytic cleavage, suggesting that an inflammatory environment may promote the formation of CysLTs through this mechanism. These results have important implications for the treatment of eosinophilic disorders such as asthma.
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10
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Guijas C, Rodríguez JP, Rubio JM, Balboa MA, Balsinde J. Phospholipase A2 regulation of lipid droplet formation. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1841:1661-71. [PMID: 25450448 DOI: 10.1016/j.bbalip.2014.10.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/02/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023]
Abstract
The classical regard of lipid droplets as mere static energy-storage organelles has evolved dramatically. Nowadays these organelles are known to participate in key processes of cell homeostasis, and their abnormal regulation is linked to several disorders including metabolic diseases (diabetes, obesity, atherosclerosis or hepatic steatosis), inflammatory responses in leukocytes, cancer development and neurodegenerative diseases. Hence, the importance of unraveling the cell mechanisms controlling lipid droplet biosynthesis, homeostasis and degradation seems evident Phospholipase A2s, a family of enzymes whose common feature is to hydrolyze the fatty acid present at the sn-2 position of phospholipids, play pivotal roles in cell signaling and inflammation. These enzymes have recently emerged as key regulators of lipid droplet homeostasis, regulating their formation at different levels. This review summarizes recent results on the roles that various phospholipase A2 forms play in the regulation of lipid droplet biogenesis under different conditions. These roles expand the already wide range of functions that these enzymes play in cell physiology and pathophysiology.
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Rubio JM, Rodríguez JP, Gil-de-Gómez L, Guijas C, Balboa MA, Balsinde J. Group V secreted phospholipase A2 is upregulated by IL-4 in human macrophages and mediates phagocytosis via hydrolysis of ethanolamine phospholipids. THE JOURNAL OF IMMUNOLOGY 2015; 194:3327-39. [PMID: 25725101 DOI: 10.4049/jimmunol.1401026] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies on the heterogeneity and plasticity of macrophage populations led to the identification of two major polarization states: classically activated macrophages or M1, induced by IFN-γ plus LPS, and alternatively activated macrophages, induced by IL-4. We studied the expression of multiple phospholipase A2 enzymes in human macrophages and the effect that polarization of the cells has on their levels. At least 11 phospholipase A2 genes were found at significant levels in human macrophages, as detected by quantitative PCR. None of these exhibited marked changes after treating the cells with IFN-γ plus LPS. However, macrophage treatment with IL-4 led to strong upregulation of the secreted group V phospholipase A2 (sPLA2-V), both at the mRNA and protein levels. In parallel with increasing sPLA2-V expression levels, IL-4-treated macrophages exhibited increased phagocytosis of yeast-derived zymosan and bacteria, and we show that both events are causally related, because cells deficient in sPLA2-V exhibited decreased phagocytosis, and cells overexpressing the enzyme manifested higher rates of phagocytosis. Mass spectrometry analyses of lipid changes in the IL-4-treated macrophages suggest that ethanolamine lysophospholipid (LPE) is an sPLA2-V-derived product that may be involved in regulating phagocytosis. Cellular levels of LPE are selectively maintained by sPLA2-V. By supplementing sPLA2-V-deficient cells with LPE, phagocytosis of zymosan or bacteria was fully restored in IL-4-treated cells. Collectively, our results show that sPLA2-V is required for efficient phagocytosis by IL-4-treated human macrophages and provide evidence that sPLA2-V-derived LPE is involved in the process.
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Affiliation(s)
- Julio M Rubio
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain; and
| | - Juan P Rodríguez
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; Laboratorio de Investigación en Proteínas, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina
| | - Luis Gil-de-Gómez
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain
| | - Carlos Guijas
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain; and
| | - María A Balboa
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain; and
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain; and
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12
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Zhao Z, Tang X, Zhao X, Zhang M, Zhang W, Hou S, Yuan W, Zhang H, Shi L, Jia H, Liang L, Lai Z, Gao J, Zhang K, Fu L, Chen W. Tylvalosin exhibits anti-inflammatory property and attenuates acute lung injury in different models possibly through suppression of NF-κB activation. Biochem Pharmacol 2014; 90:73-87. [PMID: 24792436 PMCID: PMC7092911 DOI: 10.1016/j.bcp.2014.04.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 01/11/2023]
Abstract
Tylvalosin, a new broad-spectrum, third-generation macrolides, may exert a variety of pharmacological activities. Here, we report on its anti-oxidative and anti-inflammatory activity in RAW 264.7 macrophages and mouse treated with lipopolysaccharide (LPS) as well as piglet challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Tylvalosin treatment markedly decreased IL-8, IL-6, IL-1β, PGE2, TNF-α and NO levels in vitro and in vivo. LPS and PRRSV-induced reactive oxygen species (ROS) production, and the lipid peroxidation in mice lung tissues reduced after tylvalosin treatments. In mouse acute lung injury model induced by LPS, tylvalosin administration significantly attenuated tissues injury, and reduced the inflammatory cells recruitment and activation. The evaluated phospholipase A2 (PLA2) activity and the increased expressions of cPLA2-IVA, p-cPLA2-IVA and sPLA2-IVE were lowered by tylvalosin. Consistent with the mouse results, tylvalosin pretreatment attenuated piglet lung scores with improved growth performance and normal rectal temperature in piglet model induced by PRRSV. Furthermore, tylvalosin attenuated the IκBα phosphorylation and degradation, and blocked the NF-κB p65 translocation. These results indicate that in addition to its direct antimicrobial effect, tylvalosin exhibits anti-inflammatory property and attenuates acute lung injury through suppression of NF-κB activation.
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Affiliation(s)
- Zhanzhong Zhao
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China; Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, People's Republic of China.
| | - Xiangfang Tang
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Xinghui Zhao
- Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, People's Republic of China.
| | - Minhong Zhang
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Weijian Zhang
- Shanghai Municipal Animal Innocuous Treatment Center, No. 50 Lane 4088, Puwei Road, Fengxian District, Shanghai 201415, People's Republic of China.
| | - Shaohua Hou
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Weifeng Yuan
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Hongfu Zhang
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Lijun Shi
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Hong Jia
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Lin Liang
- State Key Laboratory of Animal Nutrition, Department of Veterinary Medicine, Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, People's Republic of China.
| | - Zhi Lai
- Biopharmavet Institute, No.161 Zhenye Road, Songjiang District, Shanghai 201619, People's Republic of China.
| | - Junfeng Gao
- Biopharmavet Institute, No.161 Zhenye Road, Songjiang District, Shanghai 201619, People's Republic of China.
| | - Keyu Zhang
- Key Laboratory for Veterinary Drug Safety Evaluation and Residue Research, Department of Pharmacy, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518 Ziyue Road, Minhang District, Shanghai 200241, People's Republic of China.
| | - Ling Fu
- Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, People's Republic of China.
| | - Wei Chen
- Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, People's Republic of China.
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Nyegaard S, Novakovic VA, Rasmussen JT, Gilbert GE. Lactadherin inhibits secretory phospholipase A2 activity on pre-apoptotic leukemia cells. PLoS One 2013; 8:e77143. [PMID: 24194865 PMCID: PMC3806724 DOI: 10.1371/journal.pone.0077143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/21/2013] [Indexed: 01/09/2023] Open
Abstract
Secretory phospholipase A2 (sPLA2) is a critical component of insect and snake venoms and is secreted by mammalian leukocytes during inflammation. Elevated secretory PLA2 concentrations are associated with autoimmune diseases and septic shock. Many sPLA2’s do not bind to plasma membranes of quiescent cells but bind and digest phospholipids on the membranes of stimulated or apoptotic cells. The capacity of these phospholipases to digest membranes of stimulated or apoptotic cells correlates to the exposure of phosphatidylserine. In the present study, the ability of the phosphatidyl-L-serine-binding protein, lactadherin to inhibit phospholipase enzyme activity has been assessed. Inhibition of human secretory phospholipase A2-V on phospholipid vesicles exceeded 90%, whereas inhibition of Naja mossambica sPLA2 plateaued at 50–60%. Lactadherin inhibited 45% of activity of Naja mossambica sPLA2 and >70% of human secretory phospholipase A2-V on the membranes of human NB4 leukemia cells treated with calcium ionophore A23187. The data indicate that lactadherin may decrease inflammation by inhibiting sPLA2.
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Affiliation(s)
- Steffen Nyegaard
- Department of Molecular Biology, Aarhus University, Aarhus C, Denmark
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Valerie A. Novakovic
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jan T. Rasmussen
- Department of Molecular Biology, Aarhus University, Aarhus C, Denmark
- * E-mail:
| | - Gary E. Gilbert
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
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Ben Bacha A, Abid I, Horchani H, Mejdoub H. Enzymatic properties of stingray Dasyatis pastinaca group V, IIA and IB phospholipases A(2): a comparative study. Int J Biol Macromol 2013; 62:537-42. [PMID: 24120965 DOI: 10.1016/j.ijbiomac.2013.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 10/01/2013] [Accepted: 10/04/2013] [Indexed: 11/18/2022]
Abstract
In the present study, we have purified the group V phospholipase from the heart of cartilaginous fish stingray Dasyatis pastinaca and compared its biochemical properties with group IIA (sPLA2-IIA) and IB (sPLA2-IB) phospholipases previously purified from pancreas and intestine, respectively. Group V phospholipase (sPLA2-V) was purified to homogeneity by heat treatment, ammonium sulphate precipitation and RP-HPLC. The N-terminal sequence of the purified sPLA2-V exhibits a high degree of homology with those of mammal. The enzyme was found to be monomeric with a molecular mass estimation of 14 kDa. The specific activity of the purified enzyme, measured at pH 8 and 37 °C was 52 U/mg. Like sPLA2-IB and sPLA2-IIA, the sPLA2-V is found to be stable between pH 3 and 11 after 30 min of incubation. The purified sPLA2-V retained 65% of its activity after 10 min of incubation at 70 °C and it absolutely requires Ca(2+) for enzymatic activity. In addition it displayed high tolerance to organic solvents. Kinetic parameters Kmapp, kcat and the deduced catalytic efficiency (kcat/Kmapp) of the purified group-V, -IB and -IIA PLA2s were determined using phosphatidylethanolamine (PE), phosphatidylcholine (PC) or phosphatidylserine (PS) as substrate. The three enzymes hydrolyze the zwiterionic PE and PC substrates more efficiently than anionic PS substrate.
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Affiliation(s)
- Abir Ben Bacha
- Biochemistry Department, Science College, King Saud University, P.O. Box 22452, Riyadh 11495, Saudi Arabia; Laboratory of Plant Biotechnology Applied to Crop Improvement, Faculty of Science of Sfax, University of Sfax, Sfax 3038, Tunisia.
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15
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RHEE HAEJIN, JI LITING, KIM SEUNGHYUK, LEE JONGHO. Human group V secretory phospholipase A2 is associated with lipid rafts and internalized in a flotillin-dependent pathway. Int J Mol Med 2013; 32:1126-36. [DOI: 10.3892/ijmm.2013.1492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/23/2013] [Indexed: 11/06/2022] Open
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Abstract
LDs (lipid droplets) are metabolically highly active intracellular organelles. The lipid and protein profiles of LDs are cell-type-specific, and they undergo dynamic variation upon changes in the physiological state of a cell. It is well known that the main function of the LDs in adipocytes is to ensure energy supply and to maintain lipid homoeostasis in the body. In contrast, LDs in inflammatory cells have been implicated in eicosanoid biosynthesis, particularly under inflammatory conditions, thereby enabling them to regulate immune responses. Human mast cells are potent effector cells of the innate immune system, and the triacylglycerol (triglyceride) stores of their cytoplasmic LDs have been shown to contain large amounts of arachidonic acid, the main precursor of pro-inflammatory eicosanoids. In the present review, we discuss the current knowledge about the formation and function of LDs in inflammatory cells with specific emphasis on arachidonic acid and eicosanoid metabolism. On the basis of findings reported previously and our new observations, we propose a model in which lipolysis of LD-triacylglycerols provides arachidonic acid for lipid mediator generation in human mast cells.
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Hallstrand TS, Lai Y, Henderson WR, Altemeier WA, Gelb MH. Epithelial regulation of eicosanoid production in asthma. Pulm Pharmacol Ther 2013; 25:432-7. [PMID: 23323271 DOI: 10.1016/j.pupt.2012.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Alterations in the airway epithelium have been associated with the development of asthma in elite athletes and in subjects that are susceptible to exercise-induced bronchoconstriction (EIB). The syndrome of EIB refers to acute airflow obstruction that is triggered by a period of physical exertion. Asthmatics who are susceptible to EIB have increased levels of cysteinyl leukotrienes (CysLTs, i.e., LTs C₄, D₄, and E₄) in induced sputum and exhaled breath condensate, and greater shedding of epithelial cells into the airway lumen. Exercise challenge in individuals susceptible to this disorder initiates a sustained increase in CysLTs in the airways, and secreted mucin release and smooth muscle constriction, which may be mediated in part through activation of sensory nerves. We have identified a secreted phospholipase A₂ (sPLA₂) with increased levels in the airways of patients with EIB called sPLA₂ group X(sPLA₂-X).We have found that sPLA₂-X is strongly expressed in the airway epithelium in asthma. Further,we discovered that transglutaminase 2 (TGM2) is expressed at increased levels in asthma and serves asa regulator of sPLA₂-X. Finally, we demonstrated that sPLA₂-X acts on target cells such as eosinophils to initiate cellular eicosanoid synthesis. Collectively, these studies identify a novel mechanism linking the airway epithelium to the production of inflammatory eicosanoids by leukocytes.
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Affiliation(s)
- Teal S Hallstrand
- Division of Pulmonary and Critical Care, University of Washington, Box 356522, 1959 NE Pacific Street, Seattle, WA 98195, USA.
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18
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Pniewska E, Pawliczak R. The involvement of phospholipases A2 in asthma and chronic obstructive pulmonary disease. Mediators Inflamm 2013; 2013:793505. [PMID: 24089590 PMCID: PMC3780701 DOI: 10.1155/2013/793505] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 01/02/2013] [Accepted: 02/27/2013] [Indexed: 12/21/2022] Open
Abstract
The increased morbidity, mortality, and ineffective treatment associated with the pathogenesis of chronic inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD) have generated much research interest. The key role is played by phospholipases from the A2 superfamily: enzymes which are involved in inflammation through participation in pro- and anti-inflammatory mediators production and have an impact on many immunocompetent cells. The 30 members of the A2 superfamily are divided into 7 groups. Their role in asthma and COPD has been studied in vitro and in vivo (animal models, cell cultures, and patients). This paper contains complete and updated information about the involvement of particular enzymes in the etiology and course of asthma and COPD.
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Affiliation(s)
- Ewa Pniewska
- Department of Immunopathology, Faculty of Biomedical Sciences and Postgraduate Training, Medical University of Lodz, 7/9 Zeligowskiego Street, Building 2, Room 122, 90-752 Lodz, Poland
| | - Rafal Pawliczak
- Department of Immunopathology, Faculty of Biomedical Sciences and Postgraduate Training, Medical University of Lodz, 7/9 Zeligowskiego Street, Building 2, Room 122, 90-752 Lodz, Poland
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Meliton AY, Muñoz NM, Meliton LN, Birukova AA, Leff AR, Birukov KG. Mechanical induction of group V phospholipase A(2) causes lung inflammation and acute lung injury. Am J Physiol Lung Cell Mol Physiol 2013; 304:L689-700. [PMID: 23525785 DOI: 10.1152/ajplung.00047.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Ventilation at high tidal volume may cause lung inflammation and barrier dysfunction that culminates in ventilator-induced lung injury (VILI). However, the mechanisms by which mechanical stimulation triggers the inflammatory response have not been fully elucidated. This study tested the hypothesis that onset of VILI is triggered by activation of secretory group V phospholipase A(2) (gVPLA2) in pulmonary vascular endothelium exposed to excessive mechanical stretch. High-magnitude cyclic stretch (18% CS) increased expression and surface exposure of gVPLA2 in human pulmonary endothelial cells (EC). CS-induced gVPLA2 activation was required for activation of ICAM-1 expression and polymorphonuclear neutrophil (PMN) adhesion to CS-preconditioned EC. By contrast, physiological CS (5% CS) had no effect on gVPLA2 activation or EC-PMN adhesion. CS-induced ICAM-1 expression and EC-PMN adhesion were attenuated by the gVPLA2-blocking antibody (MCL-3G1), general inhibitor of soluble PLA2, LY311727, or siRNA-induced EC gVPLA2 knockdown. In vivo, ventilator-induced lung leukocyte recruitment, cell and protein accumulation in the alveolar space, and total lung myeloperoxidase activity were strongly suppressed in gVPLA2 mouse knockout model or upon administration of MCL-3G1. These results demonstrate a novel role for gVPLA2 as the downstream effector of pathological mechanical stretch leading to an inflammatory response associated with VILI.
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Affiliation(s)
- Angelo Y Meliton
- Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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20
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Phospholipases of mineralization competent cells and matrix vesicles: roles in physiological and pathological mineralizations. Int J Mol Sci 2013; 14:5036-129. [PMID: 23455471 PMCID: PMC3634480 DOI: 10.3390/ijms14035036] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 02/08/2023] Open
Abstract
The present review aims to systematically and critically analyze the current knowledge on phospholipases and their role in physiological and pathological mineralization undertaken by mineralization competent cells. Cellular lipid metabolism plays an important role in biological mineralization. The physiological mechanisms of mineralization are likely to take place in tissues other than in bones and teeth under specific pathological conditions. For instance, vascular calcification in arteries of patients with renal failure, diabetes mellitus or atherosclerosis recapitulates the mechanisms of bone formation. Osteoporosis—a bone resorbing disease—and rheumatoid arthritis originating from the inflammation in the synovium are also affected by cellular lipid metabolism. The focus is on the lipid metabolism due to the effects of dietary lipids on bone health. These and other phenomena indicate that phospholipases may participate in bone remodelling as evidenced by their expression in smooth muscle cells, in bone forming osteoblasts, chondrocytes and in bone resorbing osteoclasts. Among various enzymes involved, phospholipases A1 or A2, phospholipase C, phospholipase D, autotaxin and sphingomyelinase are engaged in membrane lipid remodelling during early stages of mineralization and cell maturation in mineralization-competent cells. Numerous experimental evidences suggested that phospholipases exert their action at various stages of mineralization by affecting intracellular signaling and cell differentiation. The lipid metabolites—such as arachidonic acid, lysophospholipids, and sphingosine-1-phosphate are involved in cell signaling and inflammation reactions. Phospholipases are also important members of the cellular machinery engaged in matrix vesicle (MV) biogenesis and exocytosis. They may favour mineral formation inside MVs, may catalyse MV membrane breakdown necessary for the release of mineral deposits into extracellular matrix (ECM), or participate in hydrolysis of ECM. The biological functions of phospholipases are discussed from the perspective of animal and cellular knockout models, as well as disease implications, development of potent inhibitors and therapeutic interventions.
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21
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Henderson WR, Ye X, Lai Y, Ni Z, Bollinger JG, Tien YT, Chi EY, Gelb MH. Key role of group v secreted phospholipase A2 in Th2 cytokine and dendritic cell-driven airway hyperresponsiveness and remodeling. PLoS One 2013; 8:e56172. [PMID: 23451035 PMCID: PMC3581544 DOI: 10.1371/journal.pone.0056172] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/07/2013] [Indexed: 11/23/2022] Open
Abstract
Background Previous work has shown that disruption of the gene for group X secreted phospholipase A2 (sPLA2-X) markedly diminishes airway hyperresponsiveness and remodeling in a mouse asthma model. With the large number of additional sPLA2s in the mammalian genome, the involvement of other sPLA2s in the asthma model is possible – in particular, the group V sPLA2 (sPLA2-V) that like sPLA2-X is highly active at hydrolyzing membranes of mammalian cells. Methodology and Principal Findings The allergen-driven asthma phenotype was significantly reduced in sPLA2-V-deficient mice but to a lesser extent than observed previously in sPLA2-X-deficient mice. The most striking difference observed between the sPLA2-V and sPLA2-X knockouts was the significant impairment of the primary immune response to the allergen ovalbumin (OVA) in the sPLA2-V−/− mice. The impairment in eicosanoid generation and dendritic cell activation in sPLA2-V−/− mice diminishes Th2 cytokine responses in the airways. Conclusions This paper illustrates the diverse roles of sPLA2s in the immunopathogenesis of the asthma phenotype and directs attention to developing specific inhibitors of sPLA2-V as a potential new therapy to treat asthma and other allergic disorders.
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Affiliation(s)
- William R Henderson
- Center for Allergy and Inflammation, UW Medicine at South Lake Union, Department of Medicine, University of Washington, Seattle, Washington, United States of America.
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22
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Muñoz NM, Desai A, Meliton LN, Meliton AY, Zhou T, Leff AR, Dudek SM. Group V phospholipase A(2) increases pulmonary endothelial permeability through direct hydrolysis of the cell membrane. Pulm Circ 2012; 2:182-92. [PMID: 22837859 PMCID: PMC3401872 DOI: 10.4103/2045-8932.97604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury (ALI) is characterized by inflammatory disruption of the alveolar–vascular barrier, resulting in severe respiratory compromise. Inhibition of the intercellular messenger protein, Group V phospholipase A2 (gVPLA2), blocks vascular permeability caused by LPS both in vivo and in vitro. In this investigation we studied the mechanism by which recombinant gVPLA2 increases permeability of cultured human pulmonary endothelial cells (EC). Exogenous gVPLA2 (500 nM), a highly hydrolytic enzyme, caused a significant increase in EC permeability that began within minutes and persisted for >10 hours. However, the major hydrolysis products of gVPLA2 (Lyso-PC, Lyso-PG, LPA, arachidonic acid) did not cause EC structural rearrangement or loss of barrier function at concentrations <10 μM. Higher concentrations (≥ 30 μM) of these membrane hydrolysis products caused some increased permeability but were associated with EC toxicity (measured by propidium iodide incorporation) that did not occur with barrier disruption by gVPLA2 (500 nM). Pharmacologic inhibition of multiple intracellular signaling pathways induced by gVPLA2 activity (ERK, p38, PI3K, cytosolic gIVPLA2) also did not prevent EC barrier disruption by gVPLA2. Finally, pretreatment with heparinase to prevent internalization of gVPLA2 did not inhibit EC barrier disruption by gVPLA2. Our data thus indicate that gVPLA2 increases pulmonary EC permeability directly through action as a membrane hydrolytic agent. Disruption of EC barrier function does not depend upon membrane hydrolysis products, gVPLA2 internalization, or upregulation of downstream intracellular signaling.
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Affiliation(s)
- Nilda M Muñoz
- Philippine Foundation for Lung Health, Research and Development, Inc. and Research and Biotechnology Division, St. Luke's Medical Center, Quezon City, Philippines
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Differences between group X and group V secretory phospholipase A(2) in lipolytic modification of lipoproteins. Cell Mol Biol Lett 2012; 17:459-78. [PMID: 22706677 PMCID: PMC6275602 DOI: 10.2478/s11658-012-0019-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 05/31/2012] [Indexed: 11/20/2022] Open
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are a diverse family of low molecular mass enzymes (13-18 kDa) that hydrolyze the sn-2 fatty acid ester bond of glycerophospholipids to produce free fatty acids and lysophospholipids. We have previously shown that group X sPLA(2) (sPLA(2)-X) had a strong hydrolyzing activity toward phosphatidylcholine in low-density lipoprotein (LDL) linked to the formation of lipid droplets in the cytoplasm of macrophages. Here, we show that group V sPLA(2) (sPLA(2)-V) can also cause the lipolysis of LDL, but its action differs remarkably from that of sPLA(2)-X in several respects. Although sPLA(2)-V released almost the same amount of fatty acids from LDL, it released more linoleic acid and less arachidonic acid than sPLA(2)-X. In addition, the requirement of Ca(2+) for the lipolysis of LDL was about 10-fold higher for sPLA(2)-V than sPLA(2)-X. In fact, the release of fatty acids from human serum was hardly detectable upon incubation with sPLA(2)-V in the presence of sodium citrate, which contrasted with the potent response to sPLA(2)-X. Moreover, sPLA(2)-X, but not sPLA(2)-V, was found to specifically interact with LDL among the serum proteins, as assessed by gel-filtration chromatography as well as sandwich enzyme-immunosorbent assay using anti-sPLA(2)-X and anti-apoB antibodies. Surface plasmon resonance studies have revealed that sPLA2-X can bind to LDL with high-affinity (K(d) = 3.1 nM) in the presence of Ca(2+). Selective interaction of sPLA(2)-X with LDL might be involved in the efficient hydrolysis of cell surface or intracellular phospholipids during foam cell formation.
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Sergouniotis P, Davidson A, Mackay D, Lenassi E, Li Z, Robson A, Yang X, Kam J, Isaacs T, Holder G, Jeffery G, Beck J, Moore A, Plagnol V, Webster A. Biallelic mutations in PLA2G5, encoding group V phospholipase A2, cause benign fleck retina. Am J Hum Genet 2011; 89:782-91. [PMID: 22137173 DOI: 10.1016/j.ajhg.2011.11.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/02/2011] [Accepted: 11/07/2011] [Indexed: 10/14/2022] Open
Abstract
Flecked-retina syndromes, including fundus flavimaculatus, fundus albipunctatus, and benign fleck retina, comprise a group of disorders with widespread or limited distribution of yellow-white retinal lesions of various sizes and configurations. Three siblings who have benign fleck retina and were born to consanguineous parents are the basis of this report. A combination of homozygosity mapping and exome sequencing helped to identify a homozygous missense mutation, c.133G>T (p.Gly45Cys), in PLA2G5, a gene encoding a secreted phospholipase (group V phospholipase A(2)). A screen of a further four unrelated individuals with benign fleck retina detected biallelic variants in the same gene in three patients. In contrast, no loss of function or common (minor-allele frequency>0.05%) nonsynonymous PLA2G5 variants have been previously reported (EVS, dbSNP, 1000 Genomes Project) or were detected in an internal database of 224 exomes (from subjects with adult onset neurodegenerative disease and without a diagnosis of ophthalmic disease). All seven affected individuals had fundoscopic features compatible with those previously described in benign fleck retina and no visual or electrophysiological deficits. No medical history of major illness was reported. Levels of low-density lipoprotein were mildly elevated in two patients. Optical coherence tomography and fundus autofluorescence findings suggest that group V phospholipase A(2) plays a role in the phagocytosis of photoreceptor outer-segment discs by the retinal pigment epithelium. Surprisingly, immunohistochemical staining of human retinal tissue revealed localization of the protein predominantly in the inner and outer plexiform layers.
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Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos G. Phospholipase A2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem Rev 2011; 111:6130-85. [PMID: 21910409 PMCID: PMC3196595 DOI: 10.1021/cr200085w] [Citation(s) in RCA: 804] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Yuan-Hao Hsu
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
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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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27
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Hurley BP, Pirzai W, Mumy KL, Gronert K, McCormick BA. Selective eicosanoid-generating capacity of cytoplasmic phospholipase A2 in Pseudomonas aeruginosa-infected epithelial cells. Am J Physiol Lung Cell Mol Physiol 2010; 300:L286-94. [PMID: 21097525 DOI: 10.1152/ajplung.00147.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Airway neutrophil infiltration is a pathological hallmark observed in multiple lung diseases including pneumonia and cystic fibrosis. Bacterial pathogens such as Pseudomonas aeruginosa instigate neutrophil recruitment to the air space. Excessive accumulation of neutrophils in the lung often contributes to tissue destruction. Previous studies have unveiled hepoxilin A(3) as the key molecular signal driving neutrophils across epithelial barriers. The eicosanoid hepoxilin A(3) is a potent neutrophil chemoattractant produced by epithelial cells in response to infection with P. aeruginosa. The enzyme phospholipase A(2) liberates arachidonic acid from membrane phospholipids, the rate-limiting step in the synthesis of all eicosanoids, including hepoxilin A(3). Once generated, aracidonic acid is acted upon by multiple cyclooxygenases and lipoxygenases producing an array of functionally diverse eicosanoids. Although there are numerous phospholipase A(2) isoforms capable of generating arachidonic acid, the isoform most often associated with eicosanoid generation is cytoplasmic phospholipase A(2)α. In the current study, we observed that the cytoplasmic phospholipase A(2)α isoform is required for mediating P. aeruginosa-induced production of certain eicosanoids such as prostaglandin E(2). However, we found that neutrophil transepithelial migration induced by P. aeruginosa does not require cytoplasmic phospholipase A(2)α. Furthermore, P. aeruginosa-induced hepoxilin A(3) production persists despite cytoplasmic phospholipase A(2)α suppression and generation of the 12-lipoxygenase metabolite 12-HETE is actually enhanced in this context. These results suggest that alterative phospholipase A(2) isoforms are utilized to synthesize 12-lipoxygenase metabolites. The therapeutic implications of these findings are significant when considering anti-inflammatory therapies based on targeting eicosanoid synthesis pathways.
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Affiliation(s)
- Bryan P Hurley
- Mucosal Immunology, Massachusetts General Hospital, Charlestown, 02129, USA.
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Lai Y, Oslund RC, Bollinger JG, Henderson WR, Santana LF, Altemeier WA, Gelb MH, Hallstrand TS. Eosinophil cysteinyl leukotriene synthesis mediated by exogenous secreted phospholipase A2 group X. J Biol Chem 2010; 285:41491-500. [PMID: 20974857 DOI: 10.1074/jbc.m110.153338] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Secreted phospholipase A(2) group X (sPLA(2)-X) has recently been identified in the airways of patients with asthma and may participate in cysteinyl leukotriene (CysLT; C(4), D(4), and E(4)) synthesis. We examined CysLT synthesis and arachidonic acid (AA) and lysophospholipid release by eosinophils mediated by recombinant human sPLA(2)-X. We found that recombinant sPLA(2)-X caused marked AA release and a rapid onset of CysLT synthesis in human eosinophils that was blocked by a selective sPLA(2)-X inhibitor. Exogenous sPLA(2)-X released lysophospholipid species that arise from phospholipids enriched in AA in eosinophils, including phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine as well as plasmenyl phosphatidylcholine and phosphatidylethanolamine. CysLT synthesis mediated by sPLA(2)-X but not AA release could be suppressed by inhibition of cPLA(2)α. Exogenous sPLA(2)-X initiated Ser(505) phosphorylation of cPLA(2)α, an intracellular Ca(2+) flux, and translocation of cPLA(2)α and 5-lipoxygenase in eosinophils. Synthesis of CysLTs in response to sPLA(2)-X or lysophosphatidylcholine was inhibited by p38 or JNK inhibitors but not by a MEK 1/2 inhibitor. A further increase in CysLT synthesis was induced by the addition of sPLA(2)-X to eosinophils under conditions of N-formyl-methionyl-leucyl-phenylalanine-mediated cPLA(2)α activation. These results indicate that sPLA(2)-X participates in AA and lysophospholipid release, resulting in CysLT synthesis in eosinophils through a mechanism involving p38 and JNK MAPK, cPLA(2)α, and 5-lipoxygenase activation and resulting in the amplification of CysLT synthesis during cPLA(2)α activation. Transactivation of eosinophils by sPLA(2)-X may be an important mechanism leading to CysLT formation in the airways of patients with asthma.
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Affiliation(s)
- Ying Lai
- Division of Pulmonary and Critical Care, University of Washington, Seattle, Washington 98195, USA
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Giannattasio G, Fujioka D, Xing W, Katz HR, Boyce JA, Balestrieri B. Group V secretory phospholipase A2 reveals its role in house dust mite-induced allergic pulmonary inflammation by regulation of dendritic cell function. THE JOURNAL OF IMMUNOLOGY 2010; 185:4430-8. [PMID: 20817863 DOI: 10.4049/jimmunol.1001384] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We have previously shown that group V secretory phospholipase A(2) (sPLA(2)) regulates phagocytosis of zymosan and Candida albicans by a mechanism that depends on fusion of phagosomes with late endosomes in macrophages. In this study, we report that group V sPLA(2) (Pla2g5)-null mice exposed to an extract of house dust mite Dermatophagoides farinae had markedly reduced pulmonary inflammation and goblet cell metaplasia compared with wild-type (WT) mice. Pla2g5-null mice had also impaired Th2-type adaptive immune responses to D. farinae compared with WT mice. Pla2g5-null bone marrow-derived dendritic cells (BMDCs) activated by D. farinae had delayed intracellular processing of allergen and impaired allergen-dependent maturation, a pattern recapitulated by the native lung DCs of D. farinae-challenged mice. Adoptively transferred D. farinae-loaded Pla2g5-null BMDCs were less able than D. farinae-loaded WT BMDCs to induce pulmonary inflammation and Th2 polarization in WT mice. However, Pla2g5-null recipients transferred with WT or Pla2g5-null D. farinae-loaded BMDCs exhibited significantly reduced local inflammatory responses to D. farinae, even though the transfer of WT BMDCs still induced an intact Th2 cytokine response in regional lymph nodes. Thus, the expression of group V sPLA(2) in APCs regulates Ag processing and maturation of DCs and contributes to pulmonary inflammation and immune response against D. farinae. Furthermore, an additional yet to be identified resident cell type is essential for the development of pulmonary inflammation, likely a cell in which group V sPLA(2) is upregulated by D. farinae, and whose function is also regulated by group V sPLA(2).
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Lapointe S, Brkovic A, Cloutier I, Tanguay JF, Arm JP, Sirois MG. Group V secreted phospholipase A2 contributes to LPS-induced leukocyte recruitment. J Cell Physiol 2010; 224:127-34. [PMID: 20232296 DOI: 10.1002/jcp.22106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA(2) isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA(2) (sPLA(2)-V). Furthermore, it has recently been shown that sPLA(2)-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA(2)-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA(2)-V null mice (sPLA(2)-V(-/-)) and control wild-type (WT) littermates. We observed that LPS (1 microg/ml)-mediated leukocyte emigration in sPLA(2)-V(-/-) was attenuated by 52% and 86% upon 6 and 12 h of treatment respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA(2) inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA(2)-V(-/-) mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA(2)-V(-/-) mice as compared to control WT mice. Together, our data demonstrate the role of sPLA(2)-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA(2)-V in the development of inflammatory innate immune responses.
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Affiliation(s)
- Stéphanie Lapointe
- Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, QC, Canada
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31
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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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Pérez-Chacón G, Astudillo AM, Balgoma D, Balboa MA, Balsinde J. Control of free arachidonic acid levels by phospholipases A2 and lysophospholipid acyltransferases. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:1103-13. [DOI: 10.1016/j.bbalip.2009.08.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 12/11/2022]
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Xu Y, Saegusa C, Schehr A, Grant S, Whitsett JA, Ikegami M. C/EBP{alpha} is required for pulmonary cytoprotection during hyperoxia. Am J Physiol Lung Cell Mol Physiol 2009; 297:L286-98. [PMID: 19465518 DOI: 10.1152/ajplung.00094.2009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A number of transcriptional pathways regulating fetal lung development are active during repair of the injured lung. We hypothesized that C/EBPalpha, a transcription factor critical for lung maturation, plays a role in protection of the alveolar epithelium following hyperoxic injury of the mature lung. Transgenic Cebpalpha(Delta/Delta) mice, in which Cebpalpha was conditionally deleted from Clara cells and type II cells after birth, were developed. While no pulmonary abnormalities were observed in the Cebpalpha(Delta/Delta) mice (7-8 wk old) under normal conditions, the mice were highly susceptible to hyperoxia. Cebpalpha(Delta/Delta) mice died within 4 days of exposure to 95% oxygen in association with severe lung inflammation, altered maturation of surfactant protein B and C, decreased surfactant lipid secretion, and abnormal lung mechanics at a time when all control mice survived. mRNA microarray analysis of isolated type II cells at 0, 2, and 24 h of hyperoxia demonstrated the reduced expression of number of genes regulating surfactant lipid and protein homeostasis, including Srebf, Scap, Lpcat1, Abca3, Sftpb, and Napsa. Genes influencing cell signaling or immune responses were induced in the lungs of Cebpalpha(Delta/Delta) mice. C/EBPalpha was required for the regulation of genes associated with surfactant lipid homeostasis, surfactant protein biosynthesis, processing and transport, defense response to stress, and cell redox homeostasis during exposure to hyperoxia. While C/EBPalpha did not play a critical role in postnatal pulmonary function under normal conditions, C/EBPalpha mediated protection of the lung during acute lung injury induced by hyperoxia.
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Affiliation(s)
- Yan Xu
- Cincinnati Children's Hospital Medical Center, University of Cincinnati, Ohio 45229-3039, USA
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Muñoz NM, Meliton AY, Meliton LN, Dudek SM, Leff AR. Secretory group V phospholipase A2 regulates acute lung injury and neutrophilic inflammation caused by LPS in mice. Am J Physiol Lung Cell Mol Physiol 2009; 296:L879-87. [PMID: 19286925 DOI: 10.1152/ajplung.90580.2008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We investigated the regulatory role of 14-kDa secretory group V phospholipase A(2) (gVPLA(2)) in the development of acute lung injury (ALI) and neutrophilic inflammation (NI) caused by intratracheal administration of LPS. Experiments were conducted in gVPLA(2) knockout (pla2g5(-/-)) mice, which lack the gene, and gVPLA(2) wild-type littermate control (pla2g5(+/+)) mice. Indices of pulmonary injury were evaluated 24 h after intratracheal administration of LPS. Expression of gVPLA(2) in microsections of airways and mRNA content in lung homogenates were increased substantially in pla2g5(+/+) mice after LPS-administered compared with saline-treated pla2g5(+/+) mice. By contrast, expression of gVPLA(2) was neither localized in LPS- nor saline-treated pla2g5(-/-) mice. LPS also caused 1) reduced transthoracic static compliance, 2) lung edema, 3) neutrophilic infiltration, and 4) increased neutrophil myeloperoxidase activity in pla2g5(+/+) mice. These events were attenuated in pla2g5(-/-) mice exposed to LPS or in pla2g5(+/+) mice receiving MCL-3G1, a neutralizing MAb directed against gVPLA(2), before LPS administration. Our data demonstrate that gVPLA(2) is an inducible protein in pla2g5(+/+) mice but not in pla2g5(-/-) mice within 24 h after LPS treatment. Specific inhibition of gVPLA(2) with MCL-3G1 or gene-targeted mice lacking gVPLA(2) blocks ALI and attenuates NI caused by LPS.
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Affiliation(s)
- Nilda M Muñoz
- Dept. of Medicine, M6076, Univ. of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637, USA
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Abstract
Introduction The secretory phospholipase A2 (sPLA2) family provides a seemingly endless array of potential biological functions that is only beginning to be appreciated. In humans, this family comprises 9 different members that vary in their tissue distribution, hydrolytic activity, and phospholipid substrate specificity. Through their lipase activity, these enzymes trigger various cell-signaling events to regulate cellular functions, directly kill bacteria, or modulate inflammatory responses. In addition, some sPLA2’s are high affinity ligands for cellular receptors. Objective This review merely scratches the surface of some of the actions of sPLA2s in innate immunity, inflammation, and atherosclerosis. The goal is to provide an overview of recent findings involving sPLA2s and to point to potential pathophysiologic mechanisms that may become targets for therapy.
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Lambeau G, Gelb MH. Biochemistry and physiology of mammalian secreted phospholipases A2. Annu Rev Biochem 2008; 77:495-520. [PMID: 18405237 DOI: 10.1146/annurev.biochem.76.062405.154007] [Citation(s) in RCA: 406] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phospholipases A(2) (PLA2s) are esterases that hydrolyze the sn-2 ester of glycerophospholipids and constitute one of the largest families of lipid hydrolyzing enzymes. The mammalian genome contains 10 enzymatically active secreted PLA2s (sPLA2s) and two sPLA2-related proteins devoid of lipolytic enzymatic activity. In addition to the well-established functions of one of these enzymes in digestion of dietary phospholipids and another in host defense against bacterial infections, accumulating evidence shows that some of these sPLA2s are involved in arachidonic acid release from cellular phospholipids for the biosynthesis of eicosanoids, especially during inflammation. More speculative results suggest the involvement of one or more sPLA2s in promoting atherosclerosis and cancer. In addition, the mammalian genome encodes several types of sPLA2-binding proteins, and mounting evidence shows that sPLA2s may have functions related to binding to cellular target proteins in a manner independent of their lipolytic enzymatic activity.
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Affiliation(s)
- Gérard Lambeau
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice-Sophia-Antipolis, 06560 Valbonne, France.
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Prasad VVTS, Nithipatikom K, Harder DR. Ceramide elevates 12-hydroxyeicosatetraenoic acid levels and upregulates 12-lipoxygenase in rat primary hippocampal cell cultures containing predominantly astrocytes. Neurochem Int 2008; 53:220-9. [PMID: 18680775 DOI: 10.1016/j.neuint.2008.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 06/01/2008] [Accepted: 07/01/2008] [Indexed: 10/21/2022]
Abstract
We report, exogenous addition of ceramide significantly increases 12-hydroxyeicosatetraenoic acid [12-(S)-HETE] levels, in a dose-dependent manner. 12-(S)-HETE levels, in 20, 30 and 40microM ceramide exposed rat primary hippocampal cell cultures containing predominantly astrocytes and few neurons and other glial cells (the cultured hippocampal cells were predominantly astrocytes amounting to over 99% of total cells with few neurons and other glial cells) amounted to 207, 260 and 408% of the controls, respectively. However, dihydroceramide, an inactive analog of ceramide did not alter the levels of 12-(S)-HETE. Ceramide also increased the mRNA and protein expression, and activity of 12-lipoxygease (12-LOX) needed for the synthesis of 12(S)-HETE. These results indicate a possible link between ceramide and 12-LOX pathway. However, ceramide did not alter expression of 5-lipoxygenase (5-LOX), another member of the lipoxygenase family. However, ceramide upregulated expression of cytosolic phospholipase-A(2) (cPLA(2)) and cyclooxygenase-2 (COX-2). Further, ceramide caused a significant increase in the levels of reactive oxygen species (ROS). Ceramide-mediated generation of ROS was inhibited by baicalien but not by indomethacin. In addition, ceramide treated cells exhibited increased mRNA expression of DNA damage induced transcript3 (Ddit3). This report which demonstrate induction of pro-carcinogenic 12-LOX pathway by an anticancer ceramide, may be relevant to cancer biologists studying drug resistant tumors and devising potent anticancer therapeutic strategies to treat drug resistant tumors. These results indicate possibility of 12-LOX involvement in ceramide-mediated generation of ROS and cellular oxidative stress. Induction of 12-LOX pathway by ceramide may have implications in understanding pathophysiology of neurodegenerative diseases involving ROS generation and inflammation.
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38
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Multiple roles of phospholipase A2 during lung infection and inflammation. Infect Immun 2008; 76:2259-72. [PMID: 18411286 DOI: 10.1128/iai.00059-08] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Muñoz NM, Meliton AY, Arm JP, Bonventre JV, Cho W, Leff AR. Deletion of secretory group V phospholipase A2 attenuates cell migration and airway hyperresponsiveness in immunosensitized mice. THE JOURNAL OF IMMUNOLOGY 2007; 179:4800-7. [PMID: 17878379 DOI: 10.4049/jimmunol.179.7.4800] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We investigated the role of group V phospholipase A2 (gVPLA2) in OVA-induced inflammatory cell migration and airway hyperresponsiveness (AHR) in C57BL/6 mice. Repeated allergen challenge induced biosynthesis of gVPLA2 in airways. By aerosol, gVPLA2 caused dose-related increase in airway resistance in saline-treated mice; in allergic mice, gVPLA2 caused persistent airway narrowing. Neither group IIa phospholipase A2, a close homolog of gVPLA2, nor W31A, an inactive gVPLA2 mutant with reduced activity, caused airway narrowing in immune-sensitized mice. Pretreatment with MCL-3G1, a blocking Ab against gVPLA2, before OVA challenge blocked fully gVPLA2-induced cell migration and airway narrowing as marked by reduction of migrating leukocytes in bronchoalveolar lavage fluid and decreased airway resistance. We also assessed whether nonspecific AHR caused by methacholine challenge was elicited by gVPLA2 secreted from resident airway cells of immune-sensitized mice. MCL-3G1 also blocked methacholine-induced airway bronchoconstriction in allergic mice. Blockade of bronchoconstriction by MCL-3G1 was replicated in allergic pla2g5-/- mice, which lack the gene encoding gVPLA2. Bronchoconstriction caused by gVPLA2 in pla2g4-/- mice was comparable to that in pla2g4+/+ mice. Our data demonstrate that gVPLA2 is a critical messenger enzyme in the development of AHR and regulation of cell migration during immunosensitization by a pathway that is independent of group IVa phospholipase A2.
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Affiliation(s)
- Nilda M Muñoz
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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Munoz NM, Leff AR. Highly purified selective isolation of eosinophils from human peripheral blood by negative immunomagnetic selection. Nat Protoc 2007; 1:2613-20. [PMID: 17406516 DOI: 10.1038/nprot.2006.340] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eosinophils are a minority constituent in human peripheral blood. The study of eosinophils has been limited by difficulty in achieving sufficient cell number and purity. We describe a modified protocol for immunomagnetic cell separation for efficient isolation of human peripheral blood eosinophils. We employ a mixture of monoclonal antibodies (mAbs) directed against cell-surface antigens on human hematopoietic cells combined with secondary labeling with a colloidal suspension of magnetic dextran-iron particles for negative selection of eosinophils. Unwanted labeled cells are retained in the magnetized column, permitting high recovery (70%) and purity (>98%) of eosinophils while retaining cell viability. Eosinophils remain quiescent after isolation, and stimulation caused by cytokines upregulates (i) cell-cell or cell-extracellular matrix protein adhesion, (ii) secretion of bioactive mediators and (iii) cell-surface adhesion molecules. This method for purified isolation is accomplished in < or = 4 h and preserves eosinophils in a quiescent, viable state.
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Affiliation(s)
- Nilda M Munoz
- Section of Pulmonary and Critical Care Medicine, Department of Medicine and Pediatrics, The University of Chicago, Chicago, Illinois 60637, USA
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Abstract
The Foerster resonance energy transfer-based sensor, PENN, measures intracellular phospholipase A(2) (PLA(2)) activity in living cells and small organisms. In an attempt to modify the probe for the detection of particular isoforms, we altered the sn-2 fatty acid in such a way that either one or three of the Z double bonds in arachidonic acid were present in the sensor molecule. Arachidonic-acid-mimicking fatty acids were prepared by copper-mediated coupling reactions. Probes with a single double bond in the 5-position exhibited favorable substrate properties for secretory PLA(2)s. In vitro experiments with the novel unsaturated doubly labeled phosphatidylethanolamine derivatives showed preferred cleavage of the sensor PENN2 (one double bond) by the physiologically important group V sPLA(2), while the O-methyl-derivative PMNN2 was accepted best by the isoform from hog pancreas. For experiments in living cells, we demonstrated that bioactivation via S-acetylthioethyl (SATE) groups is essential for probe performance. Surprisingly, membrane-permeant versions of the new sensors that contained double bonds, PENN2 and PENN3, were only cleaved to a minor extent in HeLa cells while the saturated form, PENN, was well accepted.
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Affiliation(s)
- Oliver Wichmann
- O. Wichmann, Dr. C. Schultz, European Molecular Biology Laboratorium, Gene Expression Programme, Meyerhofstrasse 1, 69117 Heidelberg (Germany), Fax: (+49) 6221-387206, E-mail:
| | - Michael H. Gelb
- Dr. M. H. Gelb, Department of Chemistry and Biochemistry, Campus Box 351700, Seattle, WA 98195 (USA)
| | - Carsten Schultz
- O. Wichmann, Dr. C. Schultz, European Molecular Biology Laboratorium, Gene Expression Programme, Meyerhofstrasse 1, 69117 Heidelberg (Germany), Fax: (+49) 6221-387206, E-mail:
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Hallstrand TS, Chi EY, Singer AG, Gelb MH, Henderson WR. Secreted phospholipase A2 group X overexpression in asthma and bronchial hyperresponsiveness. Am J Respir Crit Care Med 2007; 176:1072-8. [PMID: 17901411 PMCID: PMC2176098 DOI: 10.1164/rccm.200707-1088oc] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RATIONALE Secreted phospholipase A(2) enzymes (sPLA(2)s) play key regulatory roles in the biosynthesis of eicosanoids, such as the cysteinyl leukotrienes, but the role of these enzymes in the pathogenesis of asthma is not known. OBJECTIVES To establish if sPLA(2)s are overexpressed in the airways of patients with asthma, and to determine if these enzymes may play a role in the generation of eicosanoids in exercise-induced bronchoconstriction. METHODS Induced sputum samples were obtained from subjects with asthma with exercise-induced bronchoconstriction and nonasthmatic control subjects at baseline, and on a separate day 30 minutes after exercise challenge. The expression of the PLA(2)s in induced sputum cells and supernatant was determined by quantitative polymerase chain reaction, immunocytochemistry, and Western blot. MEASUREMENTS AND MAIN RESULTS The sPLA(2)s expressed at the highest levels in airway cells of subjects with asthma were groups X and XIIA. Group X sPLA(2) (sPLA(2)-X) was differentially overexpressed in asthma and localized to airway epithelial cells and bronchial macrophages. The gene expression, immunostaining in airway epithelial cells and bronchial macrophages, and the level of the extracellular sPLA(2)-X protein in the airways increased in response to exercise challenge in the asthma group, whereas the levels were lower and unchanged after challenge in nonasthmatic control subjects. CONCLUSIONS Increased expression of sPLA(2)-X may play a key role in the dysregulated eicosanoid synthesis in asthma.
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Affiliation(s)
- Teal S Hallstrand
- Division of Pulmonary and Critical Care, Department of Medicine, University of Washington, Box 356522, Seattle, WA 98195, USA.
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Ruipérez V, Casas J, Balboa MA, Balsinde J. Group V phospholipase A2-derived lysophosphatidylcholine mediates cyclooxygenase-2 induction in lipopolysaccharide-stimulated macrophages. THE JOURNAL OF IMMUNOLOGY 2007; 179:631-8. [PMID: 17579085 DOI: 10.4049/jimmunol.179.1.631] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of macrophages and macrophage cell lines by bacterial LPS elicits a delayed phase of PG biosynthesis that appears to be entirely mediated by cyclooxygenase-2 (COX-2). In previous work, we found that a catalytically active group V secreted phospholipase A(2) (sPLA(2)-V) was required for COX-2 induction, but the nature of the sPLA(2)-V metabolite involved was not defined. In this study, we identify lysophosphatidylcholine (lysoPC) as the sPLA(2)-V downstream mediator involved in COX-2 induction by LPS-stimulated macrophages. Inhibition of sPLA(2)-V by RNA interference or by the cell-permeable compound scalaradial blocked LPS-induced COX-2 expression, and this inhibition was overcome by incubating the cells with a nonhydrolyzable lysoPC analog, but not by arachidonic acid or oleic acid. Moreover, inhibition of sPLA(2)-V by scalaradial also prevented the activation of the transcription factor c-Rel, and such an inhibition was also selectively overcome by the lysoPC analog. Collectively, these results support a model whereby sPLA(2)-V hydrolysis of phospholipids upon LPS stimulation results in lysoPC generation, which in turn regulates COX-2 expression by a mechanism involving the transcriptional activity of c-Rel.
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Affiliation(s)
- Violeta Ruipérez
- Institute of Molecular Biology and Genetics, Spanish National Research Council and University of Valladolid School of Medicine, Valladolid, Spain
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Kikawada E, Bonventre JV, Arm JP. Group V secretory PLA2 regulates TLR2-dependent eicosanoid generation in mouse mast cells through amplification of ERK and cPLA2alpha activation. Blood 2007; 110:561-7. [PMID: 17369491 PMCID: PMC1924482 DOI: 10.1182/blood-2006-10-052258] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 02/06/2007] [Indexed: 01/28/2023] Open
Abstract
Mast cells may be activated through Toll-like receptors (TLRs) for the dose- and time-dependent release of eicosanoids. However, the signaling mechanisms of TLR-dependent rapid eicosanoid generation are not known. We previously reported a role for group V secretory phospholipase A(2) (PLA(2)) in regulating phagocytosis of zymosan and the ensuing eicosanoid generation in mouse resident peritoneal macrophages, suggesting a role for the enzyme in innate immunity. In the present study, we have used gene knockout mice to define an essential role for MyD88 and cytosolic PLA(2)alpha in TLR2-dependent eicosanoid generation. Furthermore, in mast cells lacking group V secretory PLA(2), the time course of phosphorylation of ERK1/2 and of cPLA(2)alpha was markedly truncated, leading to attenuation of eicosanoid generation in response to stimulation through TLR2, but not through c-kit or FcepsilonRI. These findings provide the first dissection of the mechanisms of TLR-dependent rapid eicosanoid generation, which is MyD88-dependent, requires cPLA(2)alpha, and is amplified by group V sPLA(2) through its regulation of the sequential phosphorylation and activation of ERK1/2 and cPLA(2)alpha. The findings support the suggestion that group V sPLA(2) regulates innate immune responses.
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Affiliation(s)
- Eriya Kikawada
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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Kuwata H, Fujimoto C, Yoda E, Shimbara S, Nakatani Y, Hara S, Murakami M, Kudo I. A novel role of group VIB calcium-independent phospholipase A2 (iPLA2gamma) in the inducible expression of group IIA secretory PLA2 in rat fibroblastic cells. J Biol Chem 2007; 282:20124-32. [PMID: 17475622 DOI: 10.1074/jbc.m611883200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Group IIA secretory phospholipase A(2) (sPLA(2)-IIA) is a prototypic sPLA(2) enzyme that may play roles in modification of eicosanoid biosynthesis as well as antibacterial defense. In several cell types, inducible expression of sPLA(2) by pro-inflammatory stimuli is attenuated by group IVA cytosolic PLA(2) (cPLA(2)alpha) inhibitors such as arachidonyl trifluoromethyl ketone, leading to the proposal that prior activation of cPLA(2)alpha is required for de novo induction of sPLA(2). However, because of the broad specificity of several cPLA(2)alpha inhibitors used so far, a more comprehensive approach is needed to evaluate the relevance of this ambiguous pathway. Here, we provide evidence that the induction of sPLA(2)-IIA by pro-inflammatory stimuli requires group VIB calcium-independent PLA(2) (iPLA(2)gamma), rather than cPLA(2)alpha, in rat fibroblastic 3Y1 cells. Results with small interfering RNA unexpectedly showed that the cytokine induction of sPLA(2)-IIA in cPLA(2)alpha knockdown cells, in which cPLA(2)alpha protein was undetectable, was similar to that in replicate control cells. By contrast, knockdown of iPLA(2)gamma, another arachidonyl trifluoromethyl ketone-sensitive intracellular PLA(2), markedly reduced the cytokine-induced expression of sPLA(2)-IIA. Supporting this finding, the R-enantiomer of bromoenol lactone, an iPLA(2)gamma inhibitor, suppressed the cytokine-induced sPLA(2)-IIA expression, whereas (S)-bromoenol lactone, an iPLA(2)beta inhibitor, failed to do so. Moreover, lipopolysaccharide-stimulated sPLA(2)-IIA expression was also abolished by knockdown of iPLA(2)gamma. These findings open new insight into a novel regulatory role of iPLA(2)gamma in stimulus-coupled sPLA(2)-IIA expression.
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Affiliation(s)
- Hiroshi Kuwata
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555
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Ohtsuki M, Taketomi Y, Arata S, Masuda S, Ishikawa Y, Ishii T, Takanezawa Y, Aoki J, Arai H, Yamamoto K, Kudo I, Murakami M. Transgenic expression of group V, but not group X, secreted phospholipase A2 in mice leads to neonatal lethality because of lung dysfunction. J Biol Chem 2006; 281:36420-33. [PMID: 17008322 DOI: 10.1074/jbc.m607975200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In an effort to elucidate the functions of secreted phospholipase A2 (sPLA2) enzymes in vivo, we generated transgenic (Tg) mice for group V sPLA2 (sPLA2-V) and group X sPLA2 (sPLA2-X), which act potently on phosphatidylcholine in vitro. We found that sPLA2-V Tg mice died in the neonatal period because of respiratory failure. The lungs of sPLA2-V Tg mice exhibited atelectasis with thickened alveolar walls and narrow air spaces, accompanied by infiltration of macrophages and only modest changes in eicosanoid levels. This severe pulmonary defect in sPLA2-V Tg mice was attributable to marked reduction of the lung surfactant phospholipids, phosphatidylcholine and phosphatidylglycerol. Given that the expression of sPLA2-V is greatly elevated in human lungs with severe inflammation, our present results raise the intriguing possibility that this isozyme may contribute to ongoing surfactant hydrolysis often observed in the lungs of patients with respiratory distress syndrome. In contrast, sPLA2-X Tg neonates displayed minimal abnormality of the respiratory tract with normal alveolar architecture and surfactant composition. This unexpected result was likely because sPLA2-X protein existed as an inactive zymogen in most tissues. The active form of sPLA2-X was detected in tissues with inflammatory granulation in sPLA2-X Tg mice. These results suggest that sPLA2-X mostly remains inactive under physiological conditions and that its proteolytic activation occurs during inflammation or other as yet unidentified circumstances in vivo.
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Affiliation(s)
- Mitsuhiro Ohtsuki
- Department of Health Chemistry, School of Pharmaceutical Sciences and Center for Biotechnology, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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Schaloske RH, Dennis EA. The phospholipase A2 superfamily and its group numbering system. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1246-59. [PMID: 16973413 DOI: 10.1016/j.bbalip.2006.07.011] [Citation(s) in RCA: 627] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Revised: 07/05/2006] [Accepted: 07/29/2006] [Indexed: 01/07/2023]
Abstract
The superfamily of phospholipase A(2) (PLA(2)) enzymes currently consists of 15 Groups and many subgroups and includes five distinct types of enzymes, namely the secreted PLA(2)s (sPLA(2)), the cytosolic PLA(2)s (cPLA(2)), the Ca(2+) independent PLA(2)s (iPLA(2)), the platelet-activating factor acetylhydrolases (PAF-AH), and the lysosomal PLA(2)s. In 1994, we established the systematic Group numbering system for these enzymes. Since then, the PLA(2) superfamily has grown continuously and over the intervening years has required several updates of this Group numbering system. Since our last update, a number of new PLA(2)s have been discovered and are now included. Additionally, tools for the investigation of PLA(2)s and approaches for distinguishing between the different Groups are described.
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Affiliation(s)
- Ralph H Schaloske
- Department of Pharmacology, School of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0601, USA
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Yedgar S, Cohen Y, Shoseyov D. Control of phospholipase A2 activities for the treatment of inflammatory conditions. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1373-82. [PMID: 16978919 DOI: 10.1016/j.bbalip.2006.08.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Accepted: 08/01/2006] [Indexed: 01/10/2023]
Abstract
Phospholipase-A2 (PLA2) enzymes hydrolyze cell membrane phospholipids to produce arachidonic acid (AA) and lyso-phospholipids (LysoPL), playing a key role in the production of inflammatory lipid mediators, mainly eicosanoids. They are therefore considered pro-inflammatory enzymes and their inhibition has long been recognized as a desirable therapeutic target. However, attempts to develop suitable PLA2 inhibitors for the treatment of inflammatory diseases have yet to succeed. This is due to their functional and structural diversity, and their homeostatic and even anti-inflammatory roles in certain circumstances. In the present review we outline the diversity and functions of PLA2 isoforms, and their interplay in the induction and inhibition of inflammatory processes, with emphasis on discussing approaches for therapeutic manipulation of PLA2 activities.
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Affiliation(s)
- Saul Yedgar
- Department of Biochemistry, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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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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Muñoz NM, Meliton AY, Lambertino A, Boetticher E, Learoyd J, Sultan F, Zhu X, Cho W, Leff AR. Transcellular Secretion of Group V Phospholipase A2 from Epithelium Induces β2-Integrin-Mediated Adhesion and Synthesis of Leukotriene C4 in Eosinophils. THE JOURNAL OF IMMUNOLOGY 2006; 177:574-82. [PMID: 16785555 DOI: 10.4049/jimmunol.177.1.574] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined the mechanism by which secretory group V phospholipase A(2) (gVPLA(2)) secreted from stimulated epithelial cells activates eosinophil adhesion to ICAM-1 surrogate protein and secretion of leukotriene (LT)C(4). Exogenous human group V PLA(2) (hVPLA(2)) caused an increase in surface CD11b expression and focal clustering of this integrin, which corresponded to increased beta(2) integrin-mediated adhesion. Human IIaPLA(2), a close homolog of hVPLA(2), or W31A, an inactive mutant of hVPLA(2), did not affect these responses. Exogenous lysophosphatidylcholine but not arachidonic acid mimicked the beta(2) integrin-mediated adhesion caused by hVPLA(2) activation. Inhibition of hVPLA(2) with MCL-3G1, a mAb against gVPLA(2), or with LY311727, a global secretory phospholipase A(2) (PLA(2)) inhibitor, attenuated the activity of hVPLA(2); trifluoromethylketone, an inhibitor of cytosolic group IVA PLA(2) (gIVA-PLA(2)), had no inhibitory effect on hVPLA(2)-mediated adhesion. Activation of beta(2) integrin-dependent adhesion by hVPLA(2) did not cause ERK1/2 activation and was independent of gIVA-PLA(2) phosphorylation. In other studies, eosinophils cocultured with epithelial cells were stimulated with FMLP/cytochalasin B (FMLP/B) and/or endothelin-1 (ET-1) before LTC(4) assay. FMLP/B alone caused release of LTC(4) from eosinophils, which was augmented by coculture with epithelial cells activated with ET-1. Addition of MCL-3G1 to cocultured cells caused approximately 50% inhibition of LTC(4) secretion elicited by ET-1, which was blocked further by trifluoromethylketone. Our data indicate that hVPLA(2) causes focal clustering of CD11b and beta(2) integrin adhesion by a novel mechanism that is independent of arachidonic acid synthesis and gIVA-PLA(2) activation. We also demonstrate that gVPLA(2), endogenously secreted from activated epithelial cells, promotes secretion of LTC(4) in cocultured eosinophils.
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Affiliation(s)
- Nilda M Muñoz
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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