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Xing Y, Xie SY, Deng W, Tang QZ. Cardiolipin in myocardial ischaemia-reperfusion injury: From molecular mechanisms to clinical strategies. Biomed Pharmacother 2024; 176:116936. [PMID: 38878685 DOI: 10.1016/j.biopha.2024.116936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/06/2024] [Accepted: 06/09/2024] [Indexed: 06/20/2024] Open
Abstract
Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate, characterized by various harmful effects. Tissue damage in ischemia-reperfusion injury arises from various factors, including the production of reactive oxygen species, the sequestration of proinflammatory immune cells in ischemic tissues, the induction of endoplasmic reticulum stress, and the occurrence of postischemic capillary no-reflow. Secretory phospholipase A2 (sPLA2) plays a crucial role in the eicosanoid pathway by releasing free arachidonic acid from membrane phospholipids' sn-2 position. This liberated arachidonic acid serves as a substrate for various eicosanoid biosynthetic enzymes, including cyclooxygenases, lipoxygenases, and cytochromes P450, ultimately resulting in inflammation and an elevated risk of reperfusion injury. Therefore, the activation of sPLA2 directly correlates with the heightened and accelerated damage observed in myocardial ischemia-reperfusion injury (MIRI). Presently, clinical trials are in progress for medications aimed at sPLA2, presenting promising avenues for intervention. Cardiolipin (CL) plays a crucial role in maintaining mitochondrial function, and its alteration is closely linked to mitochondrial dysfunction observed in MIRI. This paper provides a critical analysis of CL modifications concerning mitochondrial dysfunction in MIRI, along with its associated molecular mechanisms. Additionally, it delves into various pharmacological approaches to prevent or alleviate MIRI, whether by directly targeting mitochondrial CL or through indirect means.
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Affiliation(s)
- Yun Xing
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China
| | - Sai-Yang Xie
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China
| | - Wei Deng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China
| | - Qi-Zhu Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China.
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Treatment of Mouse Sperm with a Non-Catalytic Mutant of PLA2G10 Reveals That PLA2G10 Improves In Vitro Fertilization through Both Its Enzymatic Activity and as Ligand of PLA2R1. Int J Mol Sci 2022; 23:ijms23148033. [PMID: 35887380 PMCID: PMC9320362 DOI: 10.3390/ijms23148033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 12/04/2022] Open
Abstract
The group X secreted phospholipase A2 (PLA2G10) is present at high levels in mouse sperm acrosome. The enzyme is secreted during capacitation and amplifies the acrosome reaction and its own secretion via an autocrine loop. PLA2G10 also improves the rate of fertilization. In in vitro fertilization (IVF) experiments, sperm from Pla2g10-deficient mice produces fewer two-cell embryos, and the absence of PLA2G10 is rescued by adding recombinant enzymes. Moreover, wild-type (WT) sperm treated with recombinant PLA2G10 produces more two-cell embryos. The effects of PLA2G10 on mouse fertility are inhibited by sPLA2 inhibitors and rescued by products of the enzymatic reaction such as free fatty acids, suggesting a role of catalytic activity. However, PLA2G10 also binds to mouse PLA2R1, which may play a role in fertility. To determine the relative contribution of enzymatic activity and PLA2R1 binding in the profertility effect of PLA2G10, we tested H48Q-PLA2G10, a catalytically-inactive mutant of PLA2G10 with low enzymatic activity but high binding properties to PLA2R1. Its effect was tested in various mouse strains, including Pla2r1-deficient mice. H48Q-PLA2G10 did not trigger the acrosome reaction but was as potent as WT-PLA2G10 to improve IVF in inbred C57Bl/6 mice; however, this was not the case in OF1 outbred mice. Using gametes from these mouse strains, the effect of H48Q-PLA2G10 appeared dependent on both spermatozoa and oocytes. Moreover, sperm from C57Bl/6 Pla2r1-deficient mice were less fertile and lowered the profertility effects of H48Q-PLA2G10, which were completely suppressed when sperm and oocytes were collected from Pla2r1-deficient mice. Conversely, the effect of WT-PLA2G10 was not or less sensitive to the absence of PLA2R1, suggesting that the effect of PLA2G10 is polymodal and complex, acting both as an enzyme and a ligand of PLA2R1. This study shows that the action of PLA2G10 on gametes is complex and can simultaneously activate the catalytic pathway and the PLA2R1-dependent receptor pathway. This work also shows for the first time that PLA2G10 binding to gametes’ PLA2R1 participates in fertilization optimization.
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Kuefner MS. Secretory Phospholipase A2s in Insulin Resistance and Metabolism. Front Endocrinol (Lausanne) 2021; 12:732726. [PMID: 34512555 PMCID: PMC8429832 DOI: 10.3389/fendo.2021.732726] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/09/2021] [Indexed: 01/01/2023] Open
Abstract
The phospholipases A2 (PLA2) superfamily encompasses enzymes commonly found in mammalian tissues and snake venom. Many of these enzymes have unique tissue distribution, function, and substrate specificity suggesting distinct biological roles. In the past, much of the research on secretory PLA2s has analyzed their roles in inflammation, anti-bacterial actions, and atherosclerosis. In recent studies utilizing a variety of mouse models, pancreatic islets, and clinical trials, a role for many of these enzymes in the control of metabolism and insulin action has been revealed. In this review, this research, and the unique contributions of the PLA2 enzymes in insulin resistance and metabolism.
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Khan MI, Hariprasad G. Human Secretary Phospholipase A2 Mutations and Their Clinical Implications. J Inflamm Res 2020; 13:551-561. [PMID: 32982370 PMCID: PMC7502393 DOI: 10.2147/jir.s269557] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/13/2020] [Indexed: 01/05/2023] Open
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolysis of the sn-2 fatty acids of membrane phospholipids to release arachidonic acid. PLA2s are the rate limiting enzyme for the downstream synthesis of prostaglandins and leukotrienes that are the main mediators of inflammation. The extracellular forms of this enzyme are also called the secretary phospholipase A2 (sPLA2) and are distributed extensively in most of the tissues in the human body. Their integral role in inflammatory pathways has been the primary reason for the extensive research on this molecule. The catalytic mechanism of sPLA2 is initiated by a histidine/aspartic acid/calcium complex within the active site. Though they are known to have certain housekeeping functions, certain mutations of sPLA2 are known to be implicated in causation of certain pathologies leading to diseases such as atherosclerosis, cardiovascular diseases, benign fleck retina, neurodegeneration, and asthma. We present an overview of human sPLA2 and a comprehensive compilation of the mutations that result in various disease phenotypes. The study not only helps to have a holistic understanding of human sPLA2 mutations and their clinical implications, but is also a useful platform to initiate research pertaining to structure–function relationship of the mutations to develop effective therapies for management of these diseases.
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Affiliation(s)
- Mohd Imran Khan
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Gururao Hariprasad
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
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Nelson AJ, Stephenson DJ, Cardona CL, Lei X, Almutairi A, White TD, Tusing YG, Park MA, Barbour SE, Chalfant CE, Ramanadham S. Macrophage polarization is linked to Ca 2+-independent phospholipase A 2β-derived lipids and cross-cell signaling in mice. J Lipid Res 2019; 61:143-158. [PMID: 31818877 DOI: 10.1194/jlr.ra119000281] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 11/27/2019] [Indexed: 12/27/2022] Open
Abstract
Phospholipases A2 (PLA2s) catalyze hydrolysis of the sn-2 substituent from glycerophospholipids to yield a free fatty acid (i.e., arachidonic acid), which can be metabolized to pro- or anti-inflammatory eicosanoids. Macrophages modulate inflammatory responses and are affected by Ca2+-independent phospholipase A2 (PLA2)β (iPLA2β). Here, we assessed the link between iPLA2β-derived lipids (iDLs) and macrophage polarization. Macrophages from WT and KO (iPLA2β-/-) mice were classically M1 pro-inflammatory phenotype activated or alternatively M2 anti-inflammatory phenotype activated, and eicosanoid production was determined by ultra-performance LC ESI-MS/MS. As a genotypic control, we performed similar analyses on macrophages from RIP.iPLA2β.Tg mice with selective iPLA2β overexpression in β-cells. Compared with WT, generation of select pro-inflammatory prostaglandins (PGs) was lower in iPLA2β-/- , and that of a specialized pro-resolving lipid mediator (SPM), resolvin D2, was higher; both changes are consistent with the M2 phenotype. Conversely, macrophages from RIP.iPLA2β.Tg mice exhibited an opposite landscape, one associated with the M1 phenotype: namely, increased production of pro-inflammatory eicosanoids (6-keto PGF1α, PGE2, leukotriene B4) and decreased ability to generate resolvin D2. These changes were not linked with secretory PLA2 or cytosolic PLA2α or with leakage of the transgene. Thus, we report previously unidentified links between select iPLA2β-derived eicosanoids, an SPM, and macrophage polarization. Importantly, our findings reveal for the first time that β-cell iPLA2β-derived signaling can predispose macrophage responses. These findings suggest that iDLs play critical roles in macrophage polarization, and we posit that they could be targeted therapeutically to counter inflammation-based disorders.
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Affiliation(s)
- Alexander J Nelson
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Daniel J Stephenson
- Department of Cell Biology, Microbiology, and Molecular Biology (CMMB), University of South Florida, Tampa, FL 33620
| | - Christopher L Cardona
- Department of Cell Biology, Microbiology, and Molecular Biology (CMMB), University of South Florida, Tampa, FL 33620
| | - Xiaoyong Lei
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Abdulaziz Almutairi
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Tayleur D White
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ying G Tusing
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Margaret A Park
- Department of Cell Biology, Microbiology, and Molecular Biology (CMMB), University of South Florida, Tampa, FL 33620
| | - Suzanne E Barbour
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | - Charles E Chalfant
- Department of Cell Biology, Microbiology, and Molecular Biology (CMMB), University of South Florida, Tampa, FL 33620.,Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612
| | - Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294 .,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
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Nolin JD, Murphy RC, Gelb MH, Altemeier WA, Henderson WR, Hallstrand TS. Function of secreted phospholipase A 2 group-X in asthma and allergic disease. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:827-837. [PMID: 30529275 DOI: 10.1016/j.bbalip.2018.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 12/11/2022]
Abstract
Elevated secreted phospholipase A2 (sPLA2) activity in the airways has been implicated in the pathogenesis of asthma and allergic disease for some time. The identity and function of these enzymes in asthma is becoming clear from work in our lab and others. We focused on sPLA2 group X (sPLA2-X) after identifying increased levels of this enzyme in asthma, and that it is responsible for a large portion of sPLA2 activity in the airways and that the levels are strongly associated with features of airway hyperresponsiveness (AHR). In this review, we discuss studies that implicated sPLA2-X in human asthma, and murine models that demonstrate a critical role of this enzyme as a regulator of type-2 inflammation, AHR and production of eicosanoids. We discuss the mechanism by which sPLA2-X acts to regulate eicosanoids in leukocytes, as well as effects that are mediated through the generation of lysophospholipids and through receptor-mediated functions. 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)
- James D Nolin
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep, University of Washington, Seattle, WA, United States of America
| | - Ryan C Murphy
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep, University of Washington, Seattle, WA, United States of America
| | - Michael H Gelb
- Department of Chemistry, University of Washington, Seattle, WA, United States of America; Department of Biochemistry, University of Washington, Seattle, WA, United States of America
| | - William A Altemeier
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep, University of Washington, Seattle, WA, United States of America
| | - William R Henderson
- Division of Allergy and Infectious DIseases, University of Washington, Seattle, WA, United States of America
| | - Teal S Hallstrand
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep, University of Washington, Seattle, WA, United States of America.
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Shridas P, Noffsinger VP, Trumbauer AC, Webb NR. The dual role of group V secretory phospholipase A 2 in pancreatic β-cells. Endocrine 2017; 58:47-58. [PMID: 28825176 PMCID: PMC5693688 DOI: 10.1007/s12020-017-1379-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE Group X (GX) and group V (GV) secretory phospholipase A2 (sPLA2) potently release arachidonic acid (AA) from the plasma membrane of intact cells. We previously demonstrated that GX sPLA2 negatively regulates glucose-stimulated insulin secretion (GSIS) by a prostaglandin E2 (PGE2)-dependent mechanism. In this study we investigated whether GV sPLA2 similarly regulates GSIS. METHODS GSIS and pancreatic islet-size were assessed in wild-type (WT) and GV sPLA2-knock out (GV KO) mice. GSIS was also assessed ex vivo in isolated islets and in vitro using MIN6 pancreatic beta cell lines with or without GV sPLA2 overexpression or silencing. RESULTS GSIS was significantly decreased in islets isolated from GV KO mice compared to WT mice and in MIN6 cells with siRNA-mediated GV sPLA2 suppression. MIN6 cells overexpressing GV sPLA2 (MIN6-GV) showed a significant increase in GSIS compared to control cells. Though the amount of AA released into the media by MIN6-GV cells was significantly higher, PGE2 production was not enhanced or cAMP content decreased compared to control MIN6 cells. Surprisingly, GV KO mice exhibited a significant increase in plasma insulin levels following i.p. injection of glucose compared to WT mice. This increase in GSIS in GV KO mice was associated with a significant increase in pancreatic islet size and number of proliferating cells in β-islets compared to WT mice. CONCLUSIONS Deficiency of GV sPLA2 results in diminished GSIS in isolated pancreatic beta-cells. However, the reduced GSIS in islets lacking GV sPLA2 appears to be compensated by increased islet mass in GV KO mice.
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Affiliation(s)
- Preetha Shridas
- Saha Cardiovascular Research Center, University of Kentucky Medical Center, Lexington, KY, 40536, USA.
- Departments of Internal Medicine, University of Kentucky Medical Center, Lexington, KY, 40536, USA.
| | - Victoria P Noffsinger
- Saha Cardiovascular Research Center, University of Kentucky Medical Center, Lexington, KY, 40536, USA
- Departments of Internal Medicine, University of Kentucky Medical Center, Lexington, KY, 40536, USA
| | - Andrea C Trumbauer
- Saha Cardiovascular Research Center, University of Kentucky Medical Center, Lexington, KY, 40536, USA
| | - Nancy R Webb
- Saha Cardiovascular Research Center, University of Kentucky Medical Center, Lexington, KY, 40536, USA
- Pharmacology and Nutritional Sciences, Division of Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY, 40536, USA
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Rousseau M, Naika GS, Perron J, Jacques F, Gelb MH, Boilard E. Study of the role of cytosolic phospholipase A2 alpha in eicosanoid generation and thymocyte maturation in the thymus. PLoS One 2015; 10:e0126204. [PMID: 25969996 PMCID: PMC4430275 DOI: 10.1371/journal.pone.0126204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/30/2015] [Indexed: 11/29/2022] Open
Abstract
The thymus is a primary lymphoid organ, home of maturation and selection of thymocytes for generation of functional T-cells. Multiple factors are involved throughout the different stages of the maturation process to tightly regulate T-cell production. The metabolism of arachidonic acid by cyclooxygenases, lipoxygenases and specific isomerases generates eicosanoids, lipid mediators capable of triggering cellular responses. In this study, we determined the profile of expression of the eicosanoids present in the mouse thymus at different stages of thymocyte development. As the group IVA cytosolic phospholipase A2 (cPLA2α) catalyzes the hydrolysis of phospholipids, thereby generating arachidonic acid, we further verified its contribution by including cPLA2α deficient mice to our investigations. We found that a vast array of eicosanoids is expressed in the thymus, which expression is substantially modulated through thymocyte development. The cPLA2α was dispensable in the generation of most eicosanoids in the thymus and consistently, the ablation of the cPLA2α gene in mouse thymus and the culture of thymuses from human newborns in presence of the cPLA2α inhibitor pyrrophenone did not impact thymocyte maturation. This study provides information on the eicosanoid repertoire present during thymocyte development and suggests that thymocyte maturation can occur independently of cPLA2α.
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Affiliation(s)
- Matthieu Rousseau
- Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l’Université Laval, Québec, QC, Canada
| | - Gajendra S. Naika
- Department of Chemistry, University of Washington, Seattle, WA, the United States of America
| | - Jean Perron
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l’Université Laval, Québec, QC, Canada
| | - Frederic Jacques
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l’Université Laval, Québec, QC, Canada
| | - Michael H. Gelb
- Department of Chemistry, University of Washington, Seattle, WA, the United States of America
| | - Eric Boilard
- Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l’Université Laval, Québec, QC, Canada
- * E-mail:
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Layne JD, Shridas P, Webb NR. Ectopically expressed pro-group X secretory phospholipase A2 is proteolytically activated in mouse adrenal cells by furin-like proprotein convertases: implications for the regulation of adrenal steroidogenesis. J Biol Chem 2015; 290:7851-60. [PMID: 25623068 DOI: 10.1074/jbc.m114.634667] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Group X secretory phospholipase A2 (GX sPLA2) hydrolyzes mammalian cell membranes, liberating free fatty acids and lysophospholipids. GX sPLA2 is produced as a pro-enzyme (pro-GX sPLA2) that contains an N-terminal 11-amino acid propeptide ending in a dibasic motif, suggesting cleavage by a furin-like proprotein convertase (PC). Although propeptide cleavage is clearly required for enzymatic activity, the protease(s) responsible for pro-GX sPLA2 activation have not been identified. We previously reported that GX sPLA2 negatively regulates adrenal glucocorticoid production, likely by suppressing liver X receptor-mediated activation of steroidogenic acute regulatory protein expression. In this study, using a FLAG epitope-tagged pro-GX sPLA2 expression construct (FLAG-pro-GX sPLA2), we determined that adrenocorticotropic hormone (ACTH) enhanced FLAG-pro-GX sPLA2 processing and phospholipase activity secreted by Y1 adrenal cells. ACTH increased the expression of furin and PCSK6, but not other members of the PC family, in Y1 cells. Overexpression of furin and PCSK6 in HEK 293 cells significantly enhanced FLAG-pro-GX sPLA2 processing, whereas siRNA-mediated knockdown of both PCs almost completely abolished FLAG-pro-GX sPLA2 processing in Y1 cells. Expression of either furin or PCSK6 enhanced the ability of GX sPLA2 to suppress liver X receptor reporter activity. The PC inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone significantly suppressed FLAG-pro-GX sPLA2 processing and sPLA2 activity in Y1 cells, and it significantly attenuated GX sPLA2-dependent inhibition of steroidogenic acute regulatory protein expression and progesterone production. These findings provide strong evidence that pro-GX sPLA2 is a substrate for furin and PCSK6 proteolytic processing and define a novel mechanism for regulating corticosteroid production in adrenal cells.
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Affiliation(s)
- Joseph D Layne
- From the Department of Pharmacology and Nutritional Sciences, Division of Nutritional Sciences, the Saha Cardiovascular Research Center, and
| | - Preetha Shridas
- the Department of Internal Medicine, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Nancy R Webb
- the Department of Internal Medicine, University of Kentucky Medical Center, Lexington, Kentucky 40536
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Quach ND, Mock JN, Scholpa NE, Eggert MW, Payré C, Lambeau G, Arnold RD, Cummings BS. Role of the phospholipase A2 receptor in liposome drug delivery in prostate cancer cells. Mol Pharm 2014; 11:3443-51. [PMID: 25189995 PMCID: PMC4186678 DOI: 10.1021/mp500174p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The M-type phospholipase A2 receptor (PLA2R1) is a member of the C-type lectin superfamily and can internalize secreted phospholipase A2 (sPLA2) via endocytosis in non-cancer cells. sPLA2 itself was recently shown to be overexpressed in prostate tumors and to be a possible mediator of metastasis; however, little is known about the expression of PLA2R1 or its function in prostate cancers. Thus, we examined PLA2R1 expression in primary prostate cells (PCS-440-010) and human prostate cancer cells (LNCaP, DU-145, and PC-3), and we determined the effect of PLA2R1 knockdown on cytotoxicity induced by free or liposome-encapsulated chemotherapeutics. Immunoblot analysis demonstrated that the expression of PLA2R1 was higher in prostate cancer cells compared to that in primary prostate cells. Knockdown of PLA2R1 expression in PC-3 cells using shRNA increased cell proliferation and did not affect the toxicity of cisplatin, doxorubicin (Dox), and docetaxel. In contrast, PLA2R1 knockdown increased the in vitro toxicity of Dox encapsulated in sPLA2 responsive liposomes (SPRL) and correlated with increased Dox and SPRL uptake. Knockdown of PLA2R1 also increased the expression of Group IIA and X sPLA2. These data show the novel findings that PLA2R1 is expressed in prostate cancer cells, that PLA2R1 expression alters cell proliferation, and that PLA2R1 modulates the behavior of liposome-based nanoparticles. Furthermore, these studies suggest that PLA2R1 may represent a novel molecular target for controlling tumor growth or modulating delivery of lipid-based nanomedicines.
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Affiliation(s)
- N D Quach
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy University of Georgia , Athens, Georgia 30602, United States
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Beaulieu E, Ioffe J, Watson SN, Hermann PM, Wildering WC. Oxidative-stress induced increase in circulating fatty acids does not contribute to phospholipase A2-dependent appetitive long-term memory failure in the pond snail Lymnaea stagnalis. BMC Neurosci 2014; 15:56. [PMID: 24886155 PMCID: PMC4013061 DOI: 10.1186/1471-2202-15-56] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 04/23/2014] [Indexed: 11/23/2022] Open
Abstract
Background Reactive oxygen species (ROS) are essential for normal physiological functioning of the brain. However, uncompensated increase in ROS levels may results in oxidative stress. Phospholipase A2 (PLA2) is one of the key players activated by elevated ROS levels resulting in the hydrolysis of various products from the plasmamembrane such as peroxidized fatty acids. Free fatty acids (FFAs) and fatty acid metabolites are often implicated to the genesis of cognitive impairment. Previously we have shown that age-, and experimentally induced oxidative stress causes PLA2-dependent long-term memory (LTM) failure in an aversive operant conditioning model in Lymnaea stagnalis. In the present study, we investigate the effects of experimentally induced oxidative stress and the role of elevated levels of circulating FFAs on LTM function using a non-aversive appetitive classical conditioning paradigm. Results We show that intracoelomic injection of exogenous PLA2 or pro-oxidant induced PLA2 activation negatively affects LTM performance in our learning paradigm. In addition, we show that experimental induction of oxidative stress causes significant temporal changes in circulating FFA levels. Importantly, the time of training coincides with the peak of this change in lipid metabolism. However, intracoelomic injection with exogenous arachidonic acid, one of the main FFAs released by PLA2, does not affect LTM function. Moreover, sequestrating circulating FFAs with the aid of bovine serum albumin does not rescue pro-oxidant induced appetitive LTM failure. Conclusions Our data substantiates previous evidence linking lipid peroxidation and PLA2 activation to age- and oxidative stress-related cognitive impairment, neuronal dysfunction and disease. In addition however, our data indicate that lipid peroxidation induced increased levels of circulating (per)oxidized FFAs are not a factor in oxidative stress induced LTM impairment.
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Affiliation(s)
| | | | | | | | - Willem C Wildering
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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Point V, Bénarouche A, Jemel I, Parsiegla G, Lambeau G, Carrière F, Cavalier JF. Effects of the propeptide of group X secreted phospholipase A2 on substrate specificity and interfacial activity on phospholipid monolayers. Biochimie 2013; 95:51-8. [DOI: 10.1016/j.biochi.2012.07.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
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13
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The calcium chloride-induced rodent model of abdominal aortic aneurysm. Atherosclerosis 2012; 226:29-39. [PMID: 23044097 DOI: 10.1016/j.atherosclerosis.2012.09.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/01/2012] [Accepted: 09/14/2012] [Indexed: 11/22/2022]
Abstract
Abdominal aortic aneurysm (AAA) affects ∼5% men aged over 65 years and is an important cause of death in this population. Research into AAA pathogenesis has been fuelled by the need to identify new diagnostic biomarkers and therapeutic targets for this disease. One animal model of AAA involves peri-vascular application of calcium chloride (CaCl(2)) onto the infra-renal aorta of mice and rats to induce extracellular matrix remodelling. Twenty-three studies assessing CaCl(2)-induced AAA and six studies assessing AAA induced by a modified CaCl(2) method were identified. In the current report the preparation and pathological features of this AAA model are discussed. We also compared this animal model to human AAA. CaCl(2)-induced AAA shows the following pathological characteristics typically found in human AAA: calcification, inflammatory cell infiltration, oxidative stress, neovascularisation, elastin degradation and vascular smooth muscle cell apoptosis. A number of mechanisms involved in CaCl(2)-induced AAA have been identified which may be relevant to the pathogenesis of human AAA. Key molecules include c-Jun N-terminal kinase, peroxisome proliferator-activated receptor-γ, chemokine (C-C motif) receptor 2, group x secretory phospholipase A2 and plasminogen. CaCl(2)-induced AAA does not display aortic thrombus, atherosclerosis and rupture which are classical features of human AAA. Advantages of the CaCl(2)-induced AAA technique include (1) it can be applied to wild type mice making assessment of transgenic rodent models more straight forward and rapid; and (2) CaCl(2)-induced AAAs are usually developed in the infra-renal abdominal aorta, which is the most common location of human AAA. Currently findings obtained from the CaCl(2)-induced AAA model or other animal models of AAA have not been translated into the human situation. It is hoped that this deficiency will be corrected over the next decade with a number of clinical trials currently examining novel treatment options for AAA patients.
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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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Abstract
Phospholipids are present in all living organisms. They are a major component of all biological membranes, along with glycolipids and cholesterol. Enzymes aimed at cleaving the various bonds in phospholipids, namely phospholipases, are consequently widespread in nature, playing very diverse roles from aggression in snake venom to signal transduction, lipid mediators production, and digestion in humans. Although all phospholipases target phospholipids as substrates, they vary in the site of action on the phospholipids molecules, physiological function, mode of action, and their regulation. Significant studies on phospholipases characterization, physiological role, and industrial potential have been conducted worldwide. Some of them have been directed for biotechnological advances, such as gene discovery and functional enhancement by protein engineering. Others reported phospholipases as virulence factors and major causes of pathophysiological effects. In this introductory chapter, we provide brief details of different phospholipases.
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Affiliation(s)
- Ahmed Aloulou
- National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia.
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16
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Escoffier J, Pierre VJ, Jemel I, Munch L, Boudhraa Z, Ray PF, De Waard M, Lambeau G, Arnoult C. Group X secreted phospholipase A₂ specifically decreases sperm motility in mice. J Cell Physiol 2011; 226:2601-9. [PMID: 21792918 DOI: 10.1002/jcp.22606] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Different mammalian secreted phospholipases A(2) (sPLA(2) s) are expressed in male reproductive organs and/or in sperm cells but their cellular functions are still not fully characterized. Because several reports indicate a link between cellular lipids and sperm motility, we have investigated the effect of mouse group IIA, IID, IIE, V, and X sPLA(2) s on sperm motility. Among these enzymes, only mouse group X sPLA(2) (mGX sPLA(2) ) acts as a potent inhibitor of sperm motility that decreases track speed (VCL) and lateral displacement of the head (ALH) of both noncapacitated and capacitated sperm. The inhibitory effect of mGX sPLA(2) is dependent on its enzymatic activity because (i) both the proenzyme form of mGX sPLA(2) (pro-mGX) and the H48Q mutant of mGX sPLA(2) have very weak enzymatic activity and are unable to modulate sperm motility and (ii) LY329722, a specific inhibitor of sPLA(2) s, blocks the inhibitory effect of mGX sPLA(2) . Moreover, mGX sPLA(2) exerts a gradual potency on sperm subpopulations with different velocities, an effect which may be linked to the heterogeneity of lipid composition in these sperm subpopulations. Finally, we found that endogenous mGX sPLA(2) released during spontaneous acrosome reaction modulates sperm motility of capacitated sperm. Together, our results suggest a new role of sPLA(2) in sperm physiology where the sPLA2 selects a sperm subpopulation for fertilization based on its effect on sperm motility.
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17
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Watanabe K, Fujioka D, Saito Y, Nakamura T, Obata JE, Kawabata K, Watanabe Y, Mishina H, Tamaru S, Hanasaki K, Kugiyama K. Group X secretory PLA2 in neutrophils plays a pathogenic role in abdominal aortic aneurysms in mice. Am J Physiol Heart Circ Physiol 2011; 302:H95-104. [PMID: 21984544 DOI: 10.1152/ajpheart.00695.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Group X secretory PLA(2) (sPLA(2)-X) is expressed in neutrophils and plays a role in the pathogenesis of neutrophil-mediated tissue inflammation and injury. This study tested the hypothesis that sPLA(2)-X in neutrophils may contribute to the pathogenesis of abdominal aortic aneurysms (AAA) using sPLA(2)-X(-/-) mice. AAA was created by application of CaCl(2) to external surface of aorta. As a result, the aortas of sPLA(2)-X(-/-) mice had smaller diameters (percent increase from baseline; 24.8 ± 3.5% vs. 49.9 ± 9.1%, respectively; P < 0.01), a reduced grade of elastin degradation, and lower activities of elastase and gelatinase (26% and 19% lower, respectively) after CaCl(2) treatment compared with sPLA(2)-X(+/+) mice. In sPLA(2)-X(+/+) mice, immunofluorescence microscopic images showed that the immunoreactivity of sPLA(2)-X was detected only in neutrophils within aortic walls 3 days, 1, 2, and 6 wk after CaCl(2) treatment, whereas the immunoreactivity was not detected in macrophages or mast cells in aortic walls. sPLA(2)-X immunoreactivity also was colocalized in cells expressing matrix metalloproteinase (MMP)-9. Neutrophils isolated from sPLA(2)-X(-/-) mice had lower activities of elastase, gelatinase, and MMP-9 in response to stimuli compared with sPLA(2)-X(+/+) mice. The attenuated release of elastase and gelatinase from sPLA(2)-X(-/-) neutrophils was reversed by exogenous addition of mouse sPLA(2)-X protein. The adoptive transfer of sPLA(2)-X(+/+) neutrophils days 0 and 3 after CaCl(2) treatment reversed aortic diameters and elastin degradation grades in the lethally irradiated sPLA(2)-X(+/+) mice reconstituted with sPLA(2)-X(-/-) bone marrow to an extent similar to that seen in sPLA(2)-X(+/+) mice. In conclusion, sPLA(2)-X in neutrophils plays a pathogenic role in AAA in a mice model.
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Affiliation(s)
- Kazuhiro Watanabe
- Department of Internal Medicine II, University of Yamanashi, Chuo, Japan
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18
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Jemel I, Ii H, Oslund RC, Payré C, Dabert-Gay AS, Douguet D, Chargui K, Scarzello S, Gelb MH, Lambeau G. Group X secreted phospholipase A2 proenzyme is matured by a furin-like proprotein convertase and releases arachidonic acid inside of human HEK293 cells. J Biol Chem 2011; 286:36509-21. [PMID: 21878635 DOI: 10.1074/jbc.m111.268540] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Among mammalian secreted phospholipases A(2) (sPLA(2)s), group X sPLA(2) has the most potent hydrolyzing activity toward phosphatidylcholine and is involved in arachidonic acid (AA) release. Group X sPLA(2) is produced as a proenzyme and contains a short propeptide of 11 amino acids ending with a dibasic motif, suggesting cleavage by proprotein convertases. Although the removal of this propeptide is clearly required for enzymatic activity, the cellular location and the protease(s) involved in proenzyme conversion are unknown. Here we have analyzed the maturation of group X sPLA(2) in HEK293 cells, which have been extensively used to analyze sPLA(2)-induced AA release. Using recombinant mouse (PromGX) and human (ProhGX) proenzymes; HEK293 cells transfected with cDNAs coding for full-length ProhGX, PromGX, and propeptide mutants; and various permeable and non-permeable sPLA(2) inhibitors and protease inhibitors, we demonstrate that group X sPLA(2) is mainly converted intracellularly and releases AA before externalization from the cell. Most strikingly, the exogenous proenzyme does not elicit AA release, whereas the transfected proenzyme does elicit AA release in a way insensitive to non-permeable sPLA(2) inhibitors. In transfected cells, a permeable proprotein convertase inhibitor, but not a non-permeable one, prevents group X sPLA(2) maturation and partially blocks AA release. Mutations at the dibasic motif of the propeptide indicate that the last basic residue is required and sufficient for efficient maturation and AA release. All together, these results argue for the intracellular maturation of group X proenzyme in HEK293 cells by a furin-like proprotein convertase, leading to intracellular release of AA during secretion.
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Affiliation(s)
- Ikram Jemel
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR6097, CNRS et Université de Nice-Sophia-Antipolis, 660 Route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
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19
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Shridas P, Bailey WM, Talbott KR, Oslund RC, Gelb MH, Webb NR. Group X secretory phospholipase A2 enhances TLR4 signaling in macrophages. THE JOURNAL OF IMMUNOLOGY 2011; 187:482-9. [PMID: 21622863 DOI: 10.4049/jimmunol.1003552] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Secretory phospholipase A(2)s (sPLA(2)) hydrolyze glycerophospholipids to liberate lysophospholipids and free fatty acids. Although group X (GX) sPLA(2) is recognized as the most potent mammalian sPLA(2) in vitro, its precise physiological function(s) remains unclear. We recently reported that GX sPLA(2) suppresses activation of the liver X receptor in macrophages, resulting in reduced expression of liver X receptor-responsive genes including ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1), and a consequent decrease in cellular cholesterol efflux and increase in cellular cholesterol content (Shridas et al. 2010. Arterioscler. Thromb. Vasc. Biol. 30: 2014-2021). In this study, we provide evidence that GX sPLA(2) modulates macrophage inflammatory responses by altering cellular cholesterol homeostasis. Transgenic expression or exogenous addition of GX sPLA(2) resulted in a significantly higher induction of TNF-α, IL-6, and cyclooxygenase-2 in J774 macrophage-like cells in response to LPS. This effect required GX sPLA(2) catalytic activity, and was abolished in macrophages that lack either TLR4 or MyD88. The hypersensitivity to LPS in cells overexpressing GX sPLA(2) was reversed when cellular free cholesterol was normalized using cyclodextrin. Consistent with results from gain-of-function studies, peritoneal macrophages from GX sPLA(2)-deficient mice exhibited a significantly dampened response to LPS. Plasma concentrations of inflammatory cytokines were significantly lower in GX sPLA(2)-deficient mice compared with wild-type mice after LPS administration. Thus, GX sPLA(2) amplifies signaling through TLR4 by a mechanism that is dependent on its catalytic activity. Our data indicate this effect is mediated through alterations in plasma membrane free cholesterol and lipid raft content.
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Affiliation(s)
- Preetha Shridas
- University of Kentucky Medical Center, Lexington, KY 40536, USA.
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20
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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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21
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Shridas P, Bailey WM, Gizard F, Oslund RC, Gelb MH, Bruemmer D, Webb NR. Group X secretory phospholipase A2 negatively regulates ABCA1 and ABCG1 expression and cholesterol efflux in macrophages. Arterioscler Thromb Vasc Biol 2010; 30:2014-21. [PMID: 20844270 DOI: 10.1161/atvbaha.110.210237] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE GX sPLA(2) potently hydrolyzes plasma membranes to generate lysophospholipids and free fatty acids; it has been implicated in inflammatory diseases, including atherosclerosis. To identify a novel role for group X (GX) secretory phospholipase A(2) (sPLA(2)) in modulating ATP binding casette transporter A1 (ABCA1) and ATP binding casette transporter G1 (ABCG1) expression and, therefore, macrophage cholesterol efflux. METHODS AND RESULTS The overexpression or exogenous addition of GX sPLA(2) significantly reduced ABCA1 and ABCG1 expression in J774 macrophage-like cells, whereas GX sPLA(2) deficiency in mouse peritoneal macrophages was associated with enhanced expression. Altered ABC transporter expression led to reduced cholesterol efflux in GX sPLA(2)-overexpressing J774 cells and increased efflux in GX sPLA(2)-deficient mouse peritoneal macrophages. Gene regulation was dependent on GX sPLA(2) catalytic activity, mimicked by arachidonic acid and abrogated when liver X receptor (LXR)α/β expression was suppressed, and partially reversed by the LXR agonist T0901317. Reporter assays indicated that GX sPLA(2) suppresses the ability of LXR to transactivate its promoters through a mechanism involving the C-terminal portion of LXR spanning the ligand-binding domain. CONCLUSIONS GX sPLA(2) modulates gene expression in macrophages by generating lipolytic products that suppress LXR activation. GX sPLA(2) may play a previously unrecognized role in atherosclerotic lipid accumulation by negatively regulating the genes critical for cellular cholesterol efflux.
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Affiliation(s)
- Preetha Shridas
- Graduate Center for Nutritional Sciences, Saha Cardiovascular Research Center, University of Kentucky Medical Center, Lexington 40536-0200, USA
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Zack M, Boyanovsky BB, Shridas P, Bailey W, Forrest K, Howatt DA, Gelb MH, de Beer FC, Daugherty A, Webb NR. Group X secretory phospholipase A(2) augments angiotensin II-induced inflammatory responses and abdominal aortic aneurysm formation in apoE-deficient mice. Atherosclerosis 2010; 214:58-64. [PMID: 20833395 DOI: 10.1016/j.atherosclerosis.2010.08.054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/15/2010] [Accepted: 08/09/2010] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Abdominal aortic aneurysm (AAA) is a complex vascular disease characterized by matrix degradation and inflammation and is a major cause of mortality in older men. Specific interventions that prevent AAA progression remain to be identified. In this study, we tested the hypothesis that Group X secretory phospholipase A(2) (GX sPLA(2)), an enzyme implicated in inflammatory processes, mediates AAA. METHODS AND RESULTS GX sPLA(2) was detected by immunostaining in human aneurysmal tissue and in angiotensin II (Ang II)-induced AAAs in apolipoprotein E-deficient (apoE(-/-)) mice. GX sPLA(2) mRNA was increased significantly (11-fold) in abdominal aortas of apoE(-/-) mice in response to Ang II infusion. To define the role of GX sPLA(2) in experimental AAAs, apoE(-/-) and apoE(-/-) x GX sPLA(2)(-/-) (GX DKO) mice were infused with Ang II for either 10 (n=7) or 28 (n=24-26) days. Deficiency of GX sPLA(2) significantly reduced the incidence and severity of AAAs, as assessed by ultrasound measurements in vivo of aortic lumens and by computer-assisted morphometric analyses ex vivo of external diameter. Results from gene expression profiling indicated that the expression of specific matrix metalloproteinases and inflammatory mediators was blunted in aortas from GX DKO mice compared to apoE(-/-) mice after 10-day Ang II infusion. Ang II induction of cyclooxygenase-2, interleukin-6, matrix metalloproteinase (MMP)-2, MMP-13 and MMP-14 was reduced significantly in GX DKO mice compared to apoE(-/-) mice. CONCLUSION GX sPLA(2) promotes Ang II-induced pathological responses leading to AAA formation.
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Affiliation(s)
- Melissa Zack
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40536-0200, USA
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23
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Li X, Shridas P, Forrest K, Bailey W, Webb NR. Group X secretory phospholipase A2 negatively regulates adipogenesis in murine models. FASEB J 2010; 24:4313-24. [PMID: 20585029 DOI: 10.1096/fj.10-154716] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Studies in vitro indicate that group X secretory phospholipase A(2) (GX sPLA(2)) potently releases arachidonic acid (AA) and lysophosphatidylcholine from mammalian cell membranes. To define the function of GX sPLA(2) in vivo, our laboratory recently generated C57BL/6 mice with targeted deletion of GX sPLA(2) (GX(-/-) mice). When fed a normal rodent diet, GX(-/-) mice gained significantly more weight and had increased adiposity compared to GX(+/+) mice, which was not attributable to alterations in food consumption or energy expenditure. When treated with adipogenic stimuli ex vivo, stromal vascular cells isolated from adipose tissue of GX(-/-) mice accumulated significantly more (20%) triglyceride compared to cells from GX(+/+) mice. Conversely, overexpression of GX sPLA(2), but not catalytically inactive GX sPLA(2), resulted in a significant 50% reduction in triglyceride accumulation in OP9 adipocytes. The induction of genes encoding adipogenic proteins (PPARγ, SREBP-1c, SCD1, and FAS) was also significantly blunted by 50-80% in OP9 cells overexpressing GX sPLA(2). Activation of the liver X receptor (LXR), a nuclear receptor known to up-regulate adipogenic gene expression, was suppressed in 3T3-L1 and OP9 cells when GX sPLA(2) was overexpressed. Thus, hydrolytic products generated by GX sPLA(2) negatively regulate adipogenesis, possibly by suppressing LXR activation.
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Affiliation(s)
- Xia Li
- Graduate Center for Nutritional Sciences, University of Kentucky Medical Center, Lexington, KY 40536-0200, USA
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Escoffier J, Jemel I, Tanemoto A, Taketomi Y, Payre C, Coatrieux C, Sato H, Yamamoto K, Masuda S, Pernet-Gallay K, Pierre V, Hara S, Murakami M, De Waard M, Lambeau G, Arnoult C. Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice. J Clin Invest 2010; 120:1415-28. [PMID: 20424324 DOI: 10.1172/jci40494] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 02/10/2010] [Indexed: 11/17/2022] Open
Abstract
Ejaculated mammalian sperm must undergo a maturation process called capacitation before they are able to fertilize an egg. Several studies have suggested a role for members of the secreted phospholipase A2 (sPLA2) family in capacitation, acrosome reaction (AR), and fertilization, but the molecular nature of these enzymes and their specific roles have remained elusive. Here, we have demonstrated that mouse group X sPLA2 (mGX) is the major enzyme present in the acrosome of spermatozoa and that it is released in an active form during capacitation through spontaneous AR. mGX-deficient male mice produced smaller litters than wild-type male siblings when crossed with mGX-deficient females. Further analysis revealed that spermatozoa from mGX-deficient mice exhibited lower rates of spontaneous AR and that this was associated with decreased in vitro fertilization (IVF) efficiency due to a drop in the fertilization potential of the sperm and an increased rate of aborted embryos. Treatment of sperm with sPLA2 inhibitors and antibodies specific for mGX blocked spontaneous AR of wild-type sperm and reduced IVF success. Addition of lysophosphatidylcholine, a catalytic product of mGX, overcame these deficiencies. Finally, recombinant mGX triggered AR and improved IVF outcome. Taken together, our results highlight a paracrine role for mGX during capacitation in which the enzyme primes sperm for efficient fertilization and boosts premature AR of a likely phospholipid-damaged sperm subpopulation to eliminate suboptimal sperm from the pool available for fertilization.
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Shridas P, Bailey WM, Boyanovsky BB, Oslund RC, Gelb MH, Webb NR. Group X secretory phospholipase A2 regulates the expression of steroidogenic acute regulatory protein (StAR) in mouse adrenal glands. J Biol Chem 2010; 285:20031-9. [PMID: 20421306 DOI: 10.1074/jbc.m109.090423] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We developed C57BL/6 mice with targeted deletion of group X secretory phospholipase A(2) (GX KO). These mice have approximately 80% higher plasma corticosterone concentrations compared with wild-type (WT) mice under both basal and adrenocorticotropic hormone (ACTH)-induced stress conditions. This increased corticosterone level was not associated with increased circulating ACTH or a defect in the hypothalamic-pituitary axis as evidenced by a normal response to dexamethasone challenge. Primary cultures of adrenal cells from GX KO mice exhibited significantly increased corticosteroid secretion compared with WT cells. Conversely, overexpression of GX secretory phospholipase A(2) (sPLA(2)), but not a catalytically inactive mutant form of GX sPLA(2), significantly reduced steroid production 30-40% in Y1 mouse adrenal cell line. This effect was reversed by the sPLA(2) inhibitor, indoxam. Silencing of endogenous M-type receptor expression did not restore steroid production in GX sPLA(2)-overexpressing Y1 cells, ruling out a role for this sPLA(2) receptor in this regulatory process. Expression of steroidogenic acute regulatory protein (StAR), the rate-limiting protein in corticosteroid production, was approximately 2-fold higher in adrenal glands of GX KO mice compared with WT mice, whereas StAR expression was suppressed in Y1 cells overexpressing GX sPLA(2). Results from StAR-promoter luciferase reporter gene assays indicated that GX sPLA(2) antagonizes StAR promoter activity and liver X receptor-mediated StAR promoter activation. In summary, GX sPLA(2) is expressed in mouse adrenal glands and functions to negatively regulate corticosteroid synthesis, most likely by negatively regulating StAR expression.
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Affiliation(s)
- Preetha Shridas
- Graduate Center for Nutritional Sciences, the Cardiovascular Research Center, University of Kentucky Medical Center, Lexington, Kentucky 40536, USA
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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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Chalbot S, Zetterberg H, Blennow K, Fladby T, Grundke-Iqbal I, Iqbal K. Cerebrospinal fluid secretory Ca2+-dependent phospholipase A2 activity is increased in Alzheimer disease. Clin Chem 2009; 55:2171-9. [PMID: 19850632 DOI: 10.1373/clinchem.2009.130286] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The phospholipase A(2) (PLA2) family comprises multiple isoenzymes that vary in their physicochemical properties, cellular localizations, calcium sensitivities, and substrate specificities. Despite these differences, PLA2s share the ability to catalyze the synthesis of the precursors of the proinflammatory mediators. To investigate the potential of PLA2 as a biomarker in screening neuroinflammatory disorders in both clinical and research settings, we developed a PLA2 assay and determined the predominant types of PLA2 activity in cerebrospinal fluid (CSF). METHODS We used liposomes composed of a fluorescent probe (bis-Bodipy FL C11-PC [1,2-bis-(4,4- difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-undecanoyl)-sn-glycero-3-phosphocholine]) and 1,2-dioleoyl-l-alpha-phosphatidylcholine as a substrate to measure CSF PLA2 activity in a 96-well microtiter plate format. We established the type of CSF PLA2 activity using type-specific inhibitors of PLA2. RESULTS Using 5 microL CSF per assay, our PLA2 activity assay was reproducible with CVs <15% in 2 CSF samples and for recombinant secretory Ca(2+)-dependent PLA2 (sPLA2) in concentrations ranging from 0.25 to 1 micromol/L. This PLA2 assay allowed identification of sPLA2 activity in lumbar CSF from healthy individuals 20-77 years old that did not depend on either sex or age. Additionally, CSF sPLA2 activity was found to be increased (P = 0.0008) in patients with Alzheimer disease. CONCLUSIONS Adult human CSF has sPLA2 activity that can be measured reliably with the assay described. This enzyme activity in the CSF is independent of both sex and age and might serve as a valuable biomarker of neuroinflammation, as we demonstrated in Alzheimer disease.
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Affiliation(s)
- Sonia Chalbot
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314-6399, USA
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28
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Granata F, Nardicchi V, Loffredo S, Frattini A, Ilaria Staiano R, Agostini C, Triggiani M. Secreted phospholipases A(2): A proinflammatory connection between macrophages and mast cells in the human lung. Immunobiology 2009; 214:811-21. [PMID: 19628294 DOI: 10.1016/j.imbio.2009.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)) are an emerging class of mediators of inflammation. These enzymes accumulate in plasma and other biological fluids of patients with inflammatory, autoimmune and allergic diseases. sPLA(2)s are secreted at low levels in the normal airways and tend to increase during inflammatory lung diseases (e.g. bronchial asthma, chronic obstructive pulmonary disease, interstitial lung fibrosis, and sarcoidosis) as the result of plasma extravasation and/or local production. Such immune resident cells as macrophages and mast cells can be a source of sPLA(2)s in the lung. However, these cells are also targets for sPLA(2)s that sustain the activation programs of macrophages and mast cells with mechanism related to their enzymatic activity as well as to their capacity to interact with surface molecules (e.g., heparan sulfate proteoglycans, M-type receptor, mannose receptor). Recent evidence suggests that mast cells are a better source of extracellular sPLA(2)s than macrophages. On the other hand, macrophages appear to be a preferential target for sPLA(2)s. Anatomical association between macrophages and mast cells in the airways suggest that sPLA(2)s released by mast cells may activate in a paracrine fashion several macrophage functions relevant to the modulation of lung inflammation. Thus, sPLA(2)s may play a major role in inflammatory lung diseases by acting as a proinflammatory connection between macrophages and mast cells.
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Affiliation(s)
- Francescopaolo Granata
- Department of Clinical Immunology and Allergy and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy
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29
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Titsworth WL, Liu NK, Xu XM. Role of secretory phospholipase a(2) in CNS inflammation: implications in traumatic spinal cord injury. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2008; 7:254-69. [PMID: 18673210 DOI: 10.2174/187152708784936671] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are a subfamily of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor (PAF). The hydrolysis of membrane phospholipids by PLA(2) is a rate-limiting step for generation of eicosanoids and PAF. To date, more than 10 isozymes of sPLA(2) have been found in the mammalian central nervous system (CNS). Under physiological conditions, sPLA(2)s are involved in diverse cellular responses, including host defense, phospholipid digestion and metabolism. However, under pathological situations, increased sPLA(2) activity and excessive production of free fatty acids and their metabolites may lead to inflammation, loss of membrane integrity, oxidative stress, and subsequent tissue injury. Emerging evidence suggests that sPLA(2) plays a role in the secondary injury process after traumatic or ischemic injuries in the brain and spinal cord. Importantly, sPLA(2) may act as a convergence molecule that mediates multiple key mechanisms involved in the secondary injury since it can be induced by multiple toxic factors such as inflammatory cytokines, free radicals, and excitatory amino acids, and its activation and metabolites can exacerbate the secondary injury. Blocking sPLA(2) action may represent a novel and efficient strategy to block multiple injury pathways associated with the CNS secondary injury. This review outlines the current knowledge of sPLA(2) in the CNS with emphasis placed on the possible roles of sPLA(2) in mediating CNS injuries, particularly the traumatic and ischemic injuries in the brain and spinal cord.
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Affiliation(s)
- W Lee Titsworth
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY 40202, USA
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30
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Fujioka D, Saito Y, Kobayashi T, Yano T, Tezuka H, Ishimoto Y, Suzuki N, Yokota Y, Nakamura T, Obata JE, Kanazawa M, Kawabata KI, Hanasaki K, Kugiyama K. Reduction in Myocardial Ischemia/Reperfusion Injury in Group X Secretory Phospholipase A
2
–Deficient Mice. Circulation 2008; 117:2977-85. [DOI: 10.1161/circulationaha.107.743997] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Group X secretory phospholipase A
2
(sPLA
2
-X) has the most potent hydrolyzing activity toward phosphatidylcholine and elicits a marked release of arachidonic acid among several types of sPLA
2
. sPLA
2
-X is expressed in neutrophils, but its pathogenic role remains unclear.
Methods and Results—
We generated mice that lack sPLA
2
-X and studied their response to myocardial ischemia/reperfusion. The sPLA
2
-X
−/−
mice had a significant reduction in myocardial infarct size and a decrease in myocardial myeloperoxidase activity compared with sPLA
2
-X
+/+
mice. Myocardial infarct size was also significantly reduced in lethally irradiated sPLA
2
-X
+/+
mice reconstituted with sPLA
2
-X
−/−
bone marrow compared with sPLA
2
-X
+/+
bone marrow. The extent of myocardial ischemia/reperfusion injury was comparable between sPLA
2
-X
−/−
and sPLA
2
-X
+/+
mice in Langendorff experiments using isolated hearts and blood-free perfusion buffer, supporting a potential role of sPLA
2
-X in blood in myocardial ischemia/reperfusion injury. In the infarcted myocardium of sPLA
2
-X
+/+
mice, sPLA
2
-X was released from neutrophils but not myocardial tissues and platelets and was undetectable in the peripheral serum. The sPLA
2
-X
−/−
mice had lower accumulation of neutrophils in ischemic myocardium, and the isolated sPLA
2
-X
−/−
neutrophils had lower release of arachidonic acid and attenuated cytotoxic activities including respiratory burst compared with sPLA
2
-X
+/+
neutrophils. The attenuated functions of sPLA
2
-X
−/−
neutrophils were reversible by the exogenous addition of sPLA
2
-X protein. Furthermore, administration of a sPLA
2
inhibitor reduced myocardial infarct size and suppressed the cytotoxic activity of sPLA
2
-X
+/+
neutrophils.
Conclusions—
Myocardial ischemia/reperfusion injury was attenuated in sPLA
2
-X
−/−
mice partly through the suppression of neutrophil cytotoxic activities.
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Affiliation(s)
- Daisuke Fujioka
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Yukio Saito
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Tsuyoshi Kobayashi
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Toshiaki Yano
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Hideo Tezuka
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Yoshikazu Ishimoto
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Noriko Suzuki
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Yasunori Yokota
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Takamitsu Nakamura
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Jyun-ei Obata
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Masaki Kanazawa
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Ken-ichi Kawabata
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Kohji Hanasaki
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
| | - Kiyotaka Kugiyama
- From the Department of Internal Medicine II (D.F., Y.S., T.K., T.Y., T.N., J.O., M.K., K. Kawabata, K. Kugiyama) and Laboratory Animal Support Section (H.T.), Center for Life Science Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi; and Shionogi Research Laboratories, Shionogi and Co Ltd, Osaka (Y.I., N.S., Y.Y., K.H.), Japan
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31
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Peroutka RJ, Elshourbagy N, Piech T, Butt TR. Enhanced protein expression in mammalian cells using engineered SUMO fusions: secreted phospholipase A2. Protein Sci 2008; 17:1586-95. [PMID: 18539905 DOI: 10.1110/ps.035576.108] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
SUMOylation, the covalent attachment of SUMO (small ubiquitin-like modifier), is a eukaryotic post-translational event that has been demonstrated to play a critical role in several biological processes. When used as an N-terminal tag or fusion partner, SUMO has been shown to enhance functional protein production significantly by improving folding, solubility, and stability. We have engineered several SUMOs and, through their fusion, developed a system for enhancing the expression and secretion of complex proteins. To demonstrate the fidelity of this fusion technology, secreted phospholipase A(2) proteins (sPLA(2)) were produced using HEK-293T and CHO-K1 cells. Five mouse sPLA(2) homologs were expressed and secreted in mammalian cell cultures using SUMO or SUMO-derived, N-terminal fusion partners. Mean and median increases of 43- and 18-fold, respectively, were obtained using novel SUMO mutants that are resistant to digestion by endogenous deSUMOylases.
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32
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Curfs DMJ, Ghesquiere SAI, Vergouwe MN, van der Made I, Gijbels MJJ, Greaves DR, Verbeek JS, Hofker MH, de Winther MPJ. Macrophage secretory phospholipase A2 group X enhances anti-inflammatory responses, promotes lipid accumulation, and contributes to aberrant lung pathology. J Biol Chem 2008; 283:21640-8. [PMID: 18511424 DOI: 10.1074/jbc.m710584200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Secreted phospholipase A2 group X (sPLA(2)-X) is one of the most potent enzymes of the phospholipase A(2) lipolytic enzyme superfamily. Its high catalytic activity toward phosphatidylcholine (PC), the major phospholipid of cell membranes and low-density lipoproteins (LDL), has implicated sPLA(2)-X in chronic inflammatory conditions such as atherogenesis. We studied the role of sPLA(2)-X enzyme activity in vitro and in vivo, by generating sPLA(2)-X-overexpressing macrophages and transgenic macrophage-specific sPLA(2)-X mice. Our results show that sPLA(2)-X expression inhibits macrophage activation and inflammatory responses upon stimulation, characterized by reduced cell adhesion and nitric oxide production, a decrease in tumor necrosis factor (TNF), and an increase in interleukin (IL)-10. These effects were mediated by an increase in IL-6, and enhanced production of prostaglandin E(2) (PGE(2)) and 15-deoxy-Delta12,14-prostaglandin J(2) (PGJ(2)). Moreover, we found that overexpression of active sPLA(2)-X in macrophages strongly increases foam cell formation upon incubation with native LDL but also oxidized LDL (oxLDL), which is mediated by enhanced expression of scavenger receptor CD36. Transgenic sPLA(2)-X mice died neonatally because of severe lung pathology characterized by interstitial pneumonia with massive granulocyte and surfactant-laden macrophage infiltration. We conclude that overexpression of the active sPLA(2)-X enzyme results in enhanced foam cell formation but reduced activation and inflammatory responses in macrophages in vitro. Interestingly, enhanced sPLA(2)-X activity in macrophages in vivo leads to fatal pulmonary defects, suggesting a crucial role for sPLA(2)-X in inflammatory lung disease.
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Affiliation(s)
- Daniëlle M J Curfs
- Departments of Molecular Genetics and Pathology, Cardiovascular Research Institute Maastricht, Maastricht University, Universiteitssingel 50, Maastricht, The Netherlands.
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33
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Rouault M, Le Calvez C, Boilard E, Surrel F, Singer A, Ghomashchi F, Bezzine S, Scarzello S, Bollinger J, Gelb MH, Lambeau G. Recombinant production and properties of binding of the full set of mouse secreted phospholipases A2 to the mouse M-type receptor. Biochemistry 2007; 46:1647-62. [PMID: 17279628 DOI: 10.1021/bi062119b] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To date, 12 secreted phospholipases A2 (sPLA2s) have been identified in the mouse species and divided into three structural collections (I/II/V/X, III, and XII). On the basis of their different molecular properties and tissue distributions, each sPLA2 is likely to exert distinct functions by acting as an enzyme or ligand for specific soluble proteins or receptors, among which the M-type receptor is the best-characterized target. Here, we present the properties of binding of the full set of mouse sPLA2s to the mouse M-type receptor. All enzymes have been produced in Escherichia coli or insect cells, and their properties of binding to the cloned and native M-type receptor have been determined. sPLA2s IB, IIA, IIE, IIF, and X are high-affinity ligands (K0.5 = 0.3-3 nM); sPLA2s IIC and V are low-affinity ligands (K0.5 = 30-75 nM), and sPLA2s IID, III, XIIA, and XIIB bind only very weakly or do not bind to the M-type receptor (K0.5 > 100 nM). Three exogenous parvoviral group XIII PLA2s and two fungal group XIV sPLA2s do not bind to the receptor. Together, these results indicate that the mouse M-type receptor is selective for only a subset of mouse sPLA2s from the group I/II/V/X structural collection. Binding of mouse sPLA2s to a recombinant soluble mouse M-type receptor leads in all cases to inhibition of enzymatic activity, and the extent of deglycosylation of the receptor decreases yet does not abolish sPLA2 binding. The physiological meaning of binding of sPLA2 to the M-type receptor is discussed on the basis of our current knowledge of sPLA2 functions.
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Affiliation(s)
- Morgane Rouault
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
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34
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Solodkin-Szaingurten I, Levy R, Hadad N. Differential behavior of sPLA2-V and sPLA2-X in human neutrophils. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:155-63. [PMID: 17275398 DOI: 10.1016/j.bbalip.2006.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 11/30/2006] [Accepted: 11/30/2006] [Indexed: 11/29/2022]
Abstract
Neutrophils and differentiated PLB-985 cells contain various types of PLA(2)s including the 85 kDa cytosolic PLA(2) (cPLA(2)), Ca(2+)-independent PLA(2) (iPLA(2)) and secreted PLA(2)s (sPLA(2)s). The present study focuses on the behavior of sPLA(2)s in neutrophils and PLB cells and their relationship to cPLA(2)alpha. The results of the present research show that the two types of sPLA(2) present in neutrophils, sPLA(2)-V and sPLA(2)-X, which are located in the azurophil granules, are differentially affected by physiological stimuli. While sPLA(2)-V is secreted to the extacellular milieu, sPLA(2)-X is detected on the plasma membranes after stimulation. Stimulation of neutrophils with formyl-Met-Leu-Phe (fMLP), opsonized zymosan (OZ) or A23187 resulted in a different kinetics of sPLA(2) secretion as detected by its activity in the neutrophil supernatants. Neutrophil priming by inflammatory cytokines or LPS enhanced sPLA(2) activity detected in the supernatant after stimulation by fMLP. This increased activity was due to increased secretion of sPLA(2)-V to the supernatant and not to release of sPLA(2)-X. sPLA(2) in granulocyte-like PLB cells exhibit identical characteristics to neutrophil sPLA(2), with similar activity and optimal pH of 7.5. Granulocyte-like cPLA(2)alpha-deficient PLB cells serve as a good model to study whether sPLA(2) activity is regulated by cPLA(2)alpha. Secretion and activity of sPLA(2) were found to be similar in granulocyte-like PLB cells expressing or lacking cPLA(2)alpha, indicating that they are not under cPLA(2)alpha regulation.
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Affiliation(s)
- I Solodkin-Szaingurten
- Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, Beer Sheva 84105, Israel
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35
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Karabina SA, Brochériou I, Le Naour G, Agrapart M, Durand H, Gelb M, Lambeau G, Ninio E. Atherogenic properties of LDL particles modified by human group X secreted phospholipase A2 on human endothelial cell function. FASEB J 2006; 20:2547-9. [PMID: 17077289 DOI: 10.1096/fj.06-6018fje] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Increasing evidence suggests that secreted phospholipases A2 (sPLA2s) play an important role in the pathophysiology of atherosclerosis. Among sPLA2s, the human group X (hGX) enzyme has the highest catalytic activity toward phosphatidylcholine, one of the major phospholipid species of cell membranes and low-density lipoprotein (LDL). Our study examined the presence of hGX sPLA2 in human atherosclerotic lesions and investigated the ability of hGX modified LDL to alter human endothelial cell (HUVEC) function. Our results show that hGX sPLA2 is present in human atherosclerotic lesions and that the hydrolysis of LDL by hGX sPLA2 results in a modified particle that induces lipid accumulation in human monocyte-derived macrophages. Acting on endothelial cells, hGX-modified LDL activates the MAP kinase pathway, which leads to increased arachidonic acid release, increased expression of adhesion molecules on the surface of HUVEC, and increased adhesion of monocytes to HUVEC monolayers. Together, our data suggest that LDL modified by hGX, rather than hGX itself may have strong proinflammatory and proatherogenic properties, which could play an important role in the propagation of atherosclerosis.
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Affiliation(s)
- Sonia-Athina Karabina
- INSERM UMRS 525, Faculté de Médecine Pierre et Marie Curie, 91, boulevard de l'Hôpital, 75634 Paris, France.
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36
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Prijatelj P, Vardjan N, Rowan EG, Krizaj I, Pungercar J. Binding to the high-affinity M-type receptor for secreted phospholipases A2 is not obligatory for the presynaptic neurotoxicity of ammodytoxin A. Biochimie 2006; 88:1425-33. [PMID: 16815622 DOI: 10.1016/j.biochi.2006.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 06/05/2006] [Indexed: 01/19/2023]
Abstract
R180, isolated from porcine brain cortex, is a high-affinity membrane receptor for ammodytoxin A (AtxA), a secreted phospholipase A(2) (sPLA(2)) and presynaptically active neurotoxin from venom of the long-nosed viper (Vipera ammodytes ammodytes). As a member of the M-type sPLA(2) receptors, present on the mammalian plasma membrane, R180 has been proposed to be responsible for one of the first events in the process of presynaptic neurotoxicity, the binding of the toxin to the nerve cell. To test this hypothesis, we prepared and analyzed three N-terminal fusion proteins of AtxA possessing a 12 or 5 amino acid residue peptide. The presence of such an additional "propeptide" prevented interaction of the toxin with the M-type receptor but not its lethality in mouse and neurotoxic effects on a mouse phrenic nerve-hemidiaphragm preparation. In addition, antibodies raised against the sPLA(2)-binding C-type lectin-like domain 5 of the M-type sPLA(2) receptor were unable to abolish the neurotoxic action of AtxA on the neuromuscular preparation. The specific enymatic activities of the fusion AtxAs were two to three orders of magnitude lower from that of the wild type, yet resulting in a similar but less pronounced neurotoxic profile on the neuromuscular junction. This is in accordance with other data showing that a minimal enzymatic activity suffices for presynaptic toxicity of sPLA(2)s to occur. Our results indicate that the interaction of AtxA with the M-type sPLA(2) receptor at the plasma membrane is not essential for presynaptic activity of the toxin. Interaction of AtxA with two intracellular proteins, calmodulin and the R25 receptor, was affected but not prevented by the presence of the N-terminal fusion peptides, implying that these proteins may play a role in the sPLA(2) neurotoxicity.
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Affiliation(s)
- Petra Prijatelj
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1000 Ljubljana, Slovenia
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37
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Levy R. The role of cytosolic phospholipase A2-alfa in regulation of phagocytic functions. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1323-34. [PMID: 17046321 DOI: 10.1016/j.bbalip.2006.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 08/14/2006] [Accepted: 09/06/2006] [Indexed: 11/16/2022]
Abstract
Phospholipase A2(s) (PLA2(s)) are a family of enzymes that is present in a variety of mammalian and nonmammalian sources. Phagocytic cells contain cytosolic PLA2 (cPLA2) as well as several types of secreted PLA2, all of which have the potential to produce proinflammatory lipid mediators. The role of the predominant form of cPLA2 present in neutrophils is cPLA2alpha was studied by many groups. By modulating its expression in a variety of phagocytes it was found that it plays a major role in formation of eicosanoids. In addition, it was reported that cPLA2alpha also regulates the NADPH oxidase activation. The specificity of its effect on the NADPH oxidase is evident by results demonstrating that the differentiation process as well as other phagocytic functions are normal in cPLA2alpha-deficient PLB cell model. The novel dual subcellular localization of cPLA2alpha in different compartments, in the plasma membranes and in the nucleus, provides a molecular mechanism for the participation of cPLA2alpha in different processes (stimulation of NADPH oxidase and formation of eicosanoids) in the same cells.
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Affiliation(s)
- Rachel Levy
- Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, Beer Sheva 84105, Israel.
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Eerola LI, Surrel F, Nevalainen TJ, Gelb MH, Lambeau G, Laine VJO. Analysis of expression of secreted phospholipases A2 in mouse tissues at protein and mRNA levels. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:745-56. [PMID: 16757211 DOI: 10.1016/j.bbalip.2006.04.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 04/10/2006] [Accepted: 04/10/2006] [Indexed: 11/19/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)) form a group of low-molecular weight enzymes that catalyze the hydrolysis of phospholipids. Some sPLA(2)s are likely to play a role in inflammation, cancer, and as antibacterial enzymes in innate immunity. We developed specific and sensitive time-resolved fluroimmunoassays (TR-FIA) for mouse group (G) IB, GIIA, GIID, GIIE, GIIF, GV and GX sPLA(2)s and measured their concentrations in mouse serum and tissues obtained from both Balb/c and C57BL/6J mice. We also analyzed the mRNA expression of the sPLA(2)s by quantitative real-time reverse transcriptase PCR (qPCR). In most tissues, the concentrations of sPLA(2) proteins corresponded to the expression of sPLA(2)s at the mRNA level. With a few exceptions, the sPLA(2) proteins were found in the gastrointestinal tract. The qPCR results showed that GIB sPLA(2) is synthesized widely in the gastrointestinal tract, including esophagus and colon, in addition to stomach and pancreas. Our results also suggest that the loss of GIIA sPLA(2) in the intestine of GIIA sPLA(2)-deficient C57BL/6J mice is not compensated by other sPLA(2)s under normal conditions. Outside the gastrointestinal tract, sPLA(2)s were expressed occasionally in a number of tissues. The TR-FIAs developed in the current study may serve as useful tools to measure the levels of sPLA(2) proteins in mouse serum and tissues in various experimental settings.
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Affiliation(s)
- Leena I Eerola
- Department of Pathology, University of Turku, Turku, Finland
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Scott GA, Jacobs SE, Pentland AP. sPLA2-X stimulates cutaneous melanocyte dendricity and pigmentation through a lysophosphatidylcholine-dependent mechanism. J Invest Dermatol 2006; 126:855-61. [PMID: 16456529 DOI: 10.1038/sj.jid.5700180] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photoprotection of the skin is provided by melanocytes, neural crest derived cells that synthesize melanin in specialized organelles that are transferred to keratinocytes. Secretory phospholipases comprise a large family of Ca2+-dependent enzymes that liberate arachidonic acid (AA), a precursor of prostaglandins, as well as lysophospholipids. The predominant secretory phospholipase expressed by keratinocytes is group X secretory phospholipase A2 (sPLA2), which liberates large amounts of AA and the lysophospholipid lysophosphatidylcholine (LPC), from membrane preparations. Recent work by our laboratory has shown that melanocytes express receptors for prostaglandins that upon activation stimulate melanocyte dendricity and activity of tyrosinase, a key enzyme in melanin biosynthesis. In the present study, we have treated human melanocytes with recombinant sPLA2-X and show that low levels of sPLA2-X stimulate both tyrosinase activity and melanocyte dendricity. We found that the effects of sPLA2-X are mediated predominantly by LPC, not AA, and we have demonstrated expression of the phospholipase A2 receptor and two G-protein-coupled receptors for LPC (G2A and GPR119) in human melanocytes. Because secretory phospholipases are released during inflammation and are regulated by UV irradiation, our data suggest an important role for sPLA2-X in cutaneous pigmentation through the release of LPC.
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Affiliation(s)
- Glynis A Scott
- Department of Dermatology, University or Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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Hayakawa J, Ono T, Hanasaki K, Okabayashi Y. Simultaneous Quantitative Analysis for Phospholipids in Human HDL and LDL Using Two Internal Standards by Liquid Chromatography/Mass Spectrometry. ANAL LETT 2006. [DOI: 10.1080/00032710600614172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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Menschikowski M, Hagelgans A, Siegert G. Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases? Prostaglandins Other Lipid Mediat 2006; 79:1-33. [PMID: 16516807 DOI: 10.1016/j.prostaglandins.2005.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/29/2005] [Accepted: 10/31/2005] [Indexed: 02/07/2023]
Abstract
Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie and Laboratoriumsmedizin, Fetscherstrasse 74, D-01307 Dresden, Germany.
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42
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Triggiani M, Granata F, Giannattasio G, Marone G. Secretory phospholipases A2 in inflammatory and allergic diseases: not just enzymes. J Allergy Clin Immunol 2005; 116:1000-6. [PMID: 16275367 DOI: 10.1016/j.jaci.2005.08.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 08/04/2005] [Accepted: 08/08/2005] [Indexed: 12/30/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are molecules released in plasma and biologic fluids of patients with systemic inflammatory, autoimmune, and allergic diseases. Several sPLA(2) isoforms are expressed and released by such human inflammatory cells as neutrophils, eosinophils, basophils, T cells, monocytes, macrophages, and mast cells. Certain sPLA(2)s release arachidonic acid, thereby providing the substrate for the biosynthesis of proinflammatory eicosanoids. However, there are other mechanisms by which sPLA(2)s might participate in the synthesis of lipid mediators. Interestingly, sPLA(2)s activate inflammatory cells through mechanisms unrelated to their enzymatic activity. Several sPLA(2)s induce degranulation of mast cells and eosinophils and activate exocytosis in macrophages. Furthermore, sPLA(2)s promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes, and endothelial cells. Some of these effects are mediated by the binding of sPLA(2)s to specific receptors expressed on effector cells. Thus sPLA(2)s might play important roles in the initiation and amplification of the inflammatory reaction. Selective inhibitors of sPLA(2)s and specific antagonists of sPLA(2) receptors might prove useful in the treatment of allergic and autoimmune diseases, such as bronchial asthma and rheumatoid arthritis.
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Affiliation(s)
- Massimo Triggiani
- Division of Clinical Immunology and Allergy, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, Naples, Italy
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Uchiyama S, Iijima N. Partial purification and characterization of pro-phospholipase A2 activating proteases from gill membranes of the red sea bream, Chrysophrys major. Comp Biochem Physiol B Biochem Mol Biol 2005; 141:121-7. [PMID: 15820142 DOI: 10.1016/j.cbpc.2005.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 02/04/2005] [Accepted: 02/07/2005] [Indexed: 11/17/2022]
Abstract
We previously reported that gill group IB secretory phospholipase A(2) (sPLA(2)) exists as an inactive pro-sPLA(2) with the dipeptide Ala-Arg, at the N-terminus of mature sPLA(2) in mucous cells. Pro-sPLA(2) should be activated after being secreted to the surface of gill epithelia by trypsin-like protease. To clarify the above hypothesis, we investigated the existence of pro-sPLA(2) activating protease (PAP) in the gills of the red sea bream, using gill pro-sPLA(2) as a substrate. PAP was solubilized from the membrane fraction of the gills with 2% sodium cholate and partially purified by benzamidine-Sepharose chromatography and reversed-phase HPLC. Partially purified proteases, PAP1 and PAP2 showed a high molecular mass of about 200 kDa by gelatin zymography. PAP1 and PAP2 had optimal pH from 7 to 9 and were inhibited by trypsin inhibitors. These properties of PAP1 and PAP2 suggest that both enzymes belong to the membrane-associated trypsin-like serine protease family, such as enteropeptidase and corin. This is the first report verifying the existence of the activating protease of group IB pro-sPLA(2) isoforms in a non-digestive tissue.
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Affiliation(s)
- Satoshi Uchiyama
- Laboratory of Molecular Cell Biology, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashihiroshima 739-8528, Japan
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Saiga A, Uozumi N, Ono T, Seno K, Ishimoto Y, Arita H, Shimizu T, Hanasaki K. Group X secretory phospholipase A2 can induce arachidonic acid release and eicosanoid production without activation of cytosolic phospholipase A2 alpha. Prostaglandins Other Lipid Mediat 2005; 75:79-89. [PMID: 15789617 DOI: 10.1016/j.prostaglandins.2004.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Group X secretory phospholipase A2 (sPLA2-X) and cytosolic phospholipase A2 alpha (cPLA2alpha) are involved in the release of arachidonic acid (AA) from membrane phospholipids linked to the eicosanoid production in various pathological states. Recent studies have indicated the presence of various types of cross-talk between sPLA2s and cPLA2alpha resulting in effective AA release. Here we examined the dependence of sPLA2-X-induced potent AA release on the cPLA2alpha activation by using specific cPLA2alpha or sPLA2 inhibitors as well as cPLA2alpha-deficient mice. We found that Pyrrophenone, a cPLA2alpha-specific inhibitor, did not suppress the sPLA2-X-induced potent AA release and prostaglandin E2 formation in mouse spleen cells. Furthermore, the amount of AA released by sPLA2-X from spleen cells was not significantly altered by cPLA2alpha deficiency. These results suggest that sPLA2-X induces potent AA release without activation of cPLA2a, which might be relevant to eicosanoid production in some pathological states where cPLA2a is not activated.
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Affiliation(s)
- Akihiko Saiga
- Shionogi Research Laboratories, Shionogi and Co. Ltd., 3-1-1, Futaba-cho, Toyonaka, Osaka 561-0825, Japan
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Cowan MJ, Yao XL, Pawliczak R, Huang X, Logun C, Madara P, Alsaaty S, Wu T, Shelhamer JH. The role of TFIID, the initiator element and a novel 5' TFIID binding site in the transcriptional control of the TATA-less human cytosolic phospholipase A2-alpha promoter. ACTA ACUST UNITED AC 2004; 1680:145-57. [PMID: 15507318 DOI: 10.1016/j.bbaexp.2004.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Revised: 09/20/2004] [Accepted: 09/20/2004] [Indexed: 12/17/2022]
Abstract
Human cytosolic phospholipase A2-alpha (cPLA2-alpha) is a critical enzyme in the liberation of arachidonic acid (AA) from cellular membranes and the subsequent formation of prostaglandins (PGs), leukotrienes (LTs), hydroxyeicosatetraenoic acids (HETEs) and platelet activating factor in many different cell types. Much is known of the effect of posttranslational phosphorylation and calcium binding events on the enzymatic activity of cPLA2-alpha, but to date little is known about its specific transcriptional control. Through the use of reporter gene constructs and eletrophoretic mobility shift assays (EMSAs), this study determined the minimal promoter required for basal transcriptional activity of the human cPLA2-alpha promoter to include base pairs -40 through the transcription start site (TSS). In addition, it confirms the importance of an initiator (Inr) element at the TSS by deletion reporter gene analysis, and further identifies bases -3 (C) and -2 (T) as critical bases in the Inr function by mutation reporter gene analysis. Finally, this study describes a novel AAGGAG motif at -30 to -35 which is bound by TATA-box binding protein (TBP) and is critical for basal transcriptional activity.
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Affiliation(s)
- Mark J Cowan
- Division of Pulmonary and Critical Care Medicine, The University of Maryland, 10 North Greene Street, Room 3D-127, Baltimore, MD 21201, USA.
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Liberty IF, Raichel L, Hazan-Eitan Z, Pessach I, Hadad N, Schlaeffer F, Levy R. Cytosolic phospholipase A2 is responsible for prostaglandin E2 and leukotriene B4 formation in phagocyte-like PLB-985 cells: studies of differentiated cPLA2-deficient PLB-985 cells. J Leukoc Biol 2004; 76:176-84. [PMID: 15123778 DOI: 10.1189/jlb.1003453] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Our previously established model of cytosolic phospholipase A(2) (cPLA(2))-deficient, differentiated PLB-985 cells (PLB-D cells) was used to determine the physiological role of cPLA(2) in eicosanoid production. Parent PLB-985 (PLB) cells and PLB-D cells were differentiated toward the monocyte or granulocyte lineages using 5 x 10(-)(8) M 1,25 dihydroxyvitamin D(3) or 1.25% dimethyl sulfoxide, respectively. Parent monocyte- or granulocyte-like PLB cells released prostaglandin E(2) (PGE(2)) when stimulated by ionomycin, A23187, opsonized zymosan, phorbol 12-myristate 13-acetate, or formyl-Met-Leu-Phe (fMLP), and monocyte- or granulocyte-like PLB-D cells did not release PGE(2) with any of the agonists. The kinetics of cPLA(2) translocation to nuclear fractions in monocyte-like PLB cells stimulated with fMLP or ionomycin was in correlation with the kinetics of PGE(2) production. Granulocyte-like PLB cells, but not granulocyte-like PLB-D cells, secreted leukotriene B(4) (LTB(4)) after stimulation with ionomycin or A23187. Preincubation of monocyte-like parent PLB cells with 100 ng/ml lipopolysaccharide (LPS) for 16 h enhanced stimulated PGE(2) production, which is in correlation with the increased levels of cPLA(2) detected in these cells. LPS preincubation was less potent in increasing PGE(2) and LTB(4) secretion and did not affect cPLA(2) expression in granulocyte-like PLB cells, which may be a result of their lower levels of surface LPS receptor expression. LPS had no effect on monocyte- or granulocyte-like PLB-D cells. The lack of eicosanoid formation in stimulated, differentiated cPLA(2)-deficient PLB cells indicates that cPLA(2) contributes to stimulated eicosanoid formation in monocyte- and granulocyte-like PLB cells.
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Affiliation(s)
- I Furstenberg Liberty
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
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Smart BP, Pan YH, Weeks AK, Bollinger JG, Bahnson BJ, Gelb MH. Inhibition of the complete set of mammalian secreted phospholipases A2 by indole analogues. Bioorg Med Chem 2004; 12:1737-49. [PMID: 15028265 DOI: 10.1016/j.bmc.2004.01.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Accepted: 01/07/2004] [Indexed: 11/24/2022]
Abstract
Structure-guided design was employed in a search for potent and selective inhibitors of mammalian secreted phospholipases A(2) (sPLA(2)s). Using the X-ray structures of human groups IIA and X sPLA(2)s (hGIIA and hGX) as templates, homology structural models were made for the other human and mouse sPLA(2)s (hGIB, mGIB, mGIIA, mGIIC, hGIID, mGIID, hGIIE, mGIIE, hGIIF, mGIIF, hGV, mGV, and mGX). Me-Indoxam is a previously discovered indole analogue that binds tightly to many sPLA(2)s, and the X-ray structure of the hGX-Me-Indoxam complex was determined at a resolution of 2.0 A. Modeling suggests that the residues near the N(1)-substituent of Me-Indoxam vary significantly among the mammalian sPLA(2)s, and therefore a library of 83N(1)-variants was prepared by parallel synthesis. Several Me-Indoxam analogues bearing a 4-(2-oxy-ethanoic acid) side chain were potent inhibitors (IC(50) <0.05 microM) of hGIIA, mGIIA, mGIIC, hGIIE, mGIIE, hGV, and mGV, while they displayed intermediate potency (0.05-5 microM) against hGIB, mGIB, hGX, and mGX, and poorly inhibited (>5 microM) hGIID, mGIID, hGIIF, and mGIIF. Me-Indoxam analogues bearing a 5-(4-oxy-butanoic acid) side chain were generally less potent inhibitors. Although no compounds were found to be highly specific for a single human or mouse sPLA(2), combinations of Me-Indoxam analogues were discovered that could be used to distinguish the action of various sPLA(2)s in cellular events. For example, Me-Indoxam and compound 5 are approximately 5-fold more potent on hGIIA than on hGV, and compound 21 is 10-fold more potent on hGV versus hGIIA.
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Affiliation(s)
- Brian P Smart
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195, USA
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Mounier CM, Ghomashchi F, Lindsay MR, James S, Singer AG, Parton RG, Gelb MH. Arachidonic acid release from mammalian cells transfected with human groups IIA and X secreted phospholipase A(2) occurs predominantly during the secretory process and with the involvement of cytosolic phospholipase A(2)-alpha. J Biol Chem 2004; 279:25024-38. [PMID: 15007070 DOI: 10.1074/jbc.m313019200] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stable expression of human groups IIA and X secreted phospholipases A(2) (hGIIA and hGX) in CHO-K1 and HEK293 cells leads to serum- and interleukin-1beta-promoted arachidonate release. Using mutant CHO-K1 cell lines, it is shown that this arachidonate release does not require heparan sulfate proteoglycan- or glycosylphosphatidylinositol-anchored proteins. It is shown that the potent secreted phospholipase A(2) inhibitor Me-Indoxam is cell-impermeable. By use of Me-Indoxam and the cell-impermeable, secreted phospholipase A(2) trapping agent heparin, it is shown that hGIIA liberates free arachidonate prior to secretion from the cell. With hGX-transfected CHO-K1 cells, arachidonate release occurs before and after enzyme secretion, whereas all of the arachidonate release from HEK293 cells occurs prior to enzyme secretion. Immunocytochemical studies by confocal laser and electron microscopies show localization of hGIIA to the cell surface and Golgi compartment. Additional results show that the interleukin-1beta-dependent release of arachidonate is promoted by secreted phospholipase A(2) expression and is completely dependent on cytosolic (group IVA) phospholipase A(2). These results along with additional data resolve the paradox that efficient arachidonic acid release occurs with hGIIA-transfected cells, and yet exogenously added hGIIA is poorly able to liberate arachidonic acid from mammalian cells.
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Affiliation(s)
- Carine M Mounier
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195, USA
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