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Murakami M, Sato H, Taketomi Y. Modulation of immunity by the secreted phospholipase A 2 family. Immunol Rev 2023; 317:42-70. [PMID: 37035998 DOI: 10.1111/imr.13205] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/11/2023]
Abstract
Among the phospholipase A2 (PLA2 ) superfamily, which typically catalyzes the sn-2 hydrolysis of phospholipids to yield fatty acids and lysophospholipids, the secreted PLA2 (sPLA2 ) family contains 11 isoforms in mammals. Individual sPLA2 s have unique enzymatic specificity toward fatty acids and polar heads of phospholipid substrates and display distinct tissue/cellular distributions, suggesting their distinct physiological functions. Recent studies using knockout and/or transgenic mice for a full set of sPLA2 s have revealed their roles in modulation of immunity and related disorders. Application of mass spectrometric lipidomics to these mice has enabled to identify target substrates and products of individual sPLA2 s in given tissue microenvironments. sPLA2 s hydrolyze not only phospholipids in the plasma membrane of activated, damaged or dying mammalian cells, but also extracellular phospholipids such as those in extracellular vesicles, microbe membranes, lipoproteins, surfactants, and dietary phospholipids, thereby exacerbating or ameliorating various diseases. The actions of sPLA2 s are dependent on, or independent of, the generation of fatty acid- or lysophospholipid-derived lipid mediators according to the pathophysiological contexts. In this review, we make an overview of our current understanding of the roles of individual sPLA2 s in various immune responses and associated diseases.
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Affiliation(s)
- Makoto Murakami
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Hiroyasu Sato
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Taketomi
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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2
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Taketomi Y, Murakami M. Regulatory Roles of Phospholipase A2 Enzymes and Bioactive Lipids in Mast Cell Biology. Front Immunol 2022; 13:923265. [PMID: 35833146 PMCID: PMC9271868 DOI: 10.3389/fimmu.2022.923265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/30/2022] [Indexed: 11/26/2022] Open
Abstract
Lipids play fundamental roles in life as an essential component of cell membranes, as a major source of energy, as a body surface barrier, and as signaling molecules that transmit intracellular and intercellular signals. Lipid mediators, a group of bioactive lipids that mediates intercellular signals, are produced via specific biosynthetic enzymes and transmit signals via specific receptors. Mast cells, a tissue-resident immune cell population, produce several lipid mediators that contribute to exacerbation or amelioration of allergic responses and also non-allergic inflammation, host defense, cancer and fibrosis by controlling the functions of microenvironmental cells as well as mast cell themselves in paracrine and autocrine fashions. Additionally, several bioactive lipids produced by stromal cells regulate the differentiation, maturation and activation of neighboring mast cells. Many of the bioactive lipids are stored in membrane phospholipids as precursor forms and released spatiotemporally by phospholipase A2 (PLA2) enzymes. Through a series of studies employing gene targeting and lipidomics, several enzymes belonging to the PLA2 superfamily have been demonstrated to participate in mast cell-related diseases by mobilizing unique bioactive lipids in multiple ways. In this review, we provide an overview of our current understanding of the regulatory roles of several PLA2-driven lipid pathways in mast cell biology.
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Kudo K, Miki Y, Carreras J, Nakayama S, Nakamoto Y, Ito M, Nagashima E, Yamamoto K, Higuchi H, Morita SY, Inoue A, Aoki J, Ando K, Nakamura N, Murakami M, Kotani A. Secreted phospholipase A 2 modifies extracellular vesicles and accelerates B cell lymphoma. Cell Metab 2022; 34:615-633.e8. [PMID: 35294862 DOI: 10.1016/j.cmet.2022.02.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 11/15/2021] [Accepted: 02/22/2022] [Indexed: 12/26/2022]
Abstract
Extracellular vesicles (EVs) including exosomes act as intercellular communicators by transferring protein and microRNA cargoes, yet the role of EV lipids remains unclear. Here, we show that the pro-tumorigenic action of lymphoma-derived EVs is augmented via secreted phospholipase A2 (sPLA2)-driven lipid metabolism. Hydrolysis of EV phospholipids by group X sPLA2, which was induced in macrophages of Epstein-Barr virus (EBV) lymphoma, increased the production of fatty acids, lysophospholipids, and their metabolites. sPLA2-treated EVs were smaller and self-aggregated, showed better uptake, and increased cytokine expression and lipid mediator signaling in tumor-associated macrophages. Pharmacological inhibition of endogenous sPLA2 suppressed lymphoma growth in EBV-infected humanized mice, while treatment with sPLA2-modified EVs reversed this phenotype. Furthermore, sPLA2 expression in human large B cell lymphomas inversely correlated with patient survival. Overall, the sPLA2-mediated EV modification promotes tumor development, highlighting a non-canonical mechanistic action of EVs as an extracellular hydrolytic platform of sPLA2.
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Affiliation(s)
- Kai Kudo
- Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan; Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Japan
| | - Yoshimi Miki
- Laboratory of Microenvironmental Metabolic Health Sciences Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Joaquim Carreras
- Department of Pathology, Tokai University School of Medicine, Isehara, Japan
| | - Shunya Nakayama
- Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan; Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Japan; Department of Hematology and Oncology, Tokai University School of Medicine, Isehara, Japan
| | - Yasushi Nakamoto
- Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan; Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Japan
| | - Masatoshi Ito
- Support Center for Medical Research and Education, Tokai University School of Medicine, Isehara, Japan
| | - Etsuko Nagashima
- Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan; Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Japan
| | - Kei Yamamoto
- Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | - Hiroshi Higuchi
- Center for Cancer Immunology, Cutaneous Biology Research Center, Center for Cancer Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shin-Ya Morita
- Department of Pharmacy, Shiga University of Medical Science Hospital, Otsu, Japan
| | - Asuka Inoue
- Department of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kiyoshi Ando
- Department of Hematology and Oncology, Tokai University School of Medicine, Isehara, Japan
| | - Naoya Nakamura
- Department of Pathology, Tokai University School of Medicine, Isehara, Japan
| | - Makoto Murakami
- Laboratory of Microenvironmental Metabolic Health Sciences Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
| | - Ai Kotani
- Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan; Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Japan.
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4
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Morris G, Berk M, Walder K, O'Neil A, Maes M, Puri BK. The lipid paradox in neuroprogressive disorders: Causes and consequences. Neurosci Biobehav Rev 2021; 128:35-57. [PMID: 34118292 DOI: 10.1016/j.neubiorev.2021.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 04/27/2021] [Accepted: 06/06/2021] [Indexed: 02/07/2023]
Abstract
Chronic systemic inflammation is associated with an increased risk of cardiovascular disease in an environment of low low-density lipoprotein (LDL) and low total cholesterol and with the pathophysiology of neuroprogressive disorders. The causes and consequences of this lipid paradox are explored. Circulating activated neutrophils can release inflammatory molecules such as myeloperoxidase and the pro-inflammatory cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. Since activated neutrophils are associated with atherosclerosis and cardiovascular disease and with major depressive disorder, bipolar disorder and schizophrenia, it seems reasonable to hypothesise that the inflammatory molecules released by them may act as mediators of the link between systemic inflammation and the development of atherosclerosis in neuroprogressive disorders. This hypothesis is tested by considering the association at a molecular level of systemic inflammation with increased LDL oxidation; increased small dense LDL levels; increased lipoprotein (a) concentration; secretory phospholipase A2 activation; cytosolic phospholipase A2 activation; increased platelet activation; decreased apolipoprotein A1 levels and function; decreased paroxonase-1 activity; hyperhomocysteinaemia; and metabolic endotoxaemia. These molecular mechanisms suggest potential therapeutic targets.
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | - Michael Berk
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, the Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Ken Walder
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | - Adrienne O'Neil
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | - Michael Maes
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, King Chulalongkorn University Hospital, Bangkok, Thailand
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Morris G, Puri BK, Bortolasci CC, Carvalho A, Berk M, Walder K, Moreira EG, Maes M. The role of high-density lipoprotein cholesterol, apolipoprotein A and paraoxonase-1 in the pathophysiology of neuroprogressive disorders. Neurosci Biobehav Rev 2021; 125:244-263. [PMID: 33657433 DOI: 10.1016/j.neubiorev.2021.02.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 01/29/2021] [Accepted: 02/23/2021] [Indexed: 12/11/2022]
Abstract
Lowered high-density lipoprotein (HDL) cholesterol has been reported in major depressive disorder, bipolar disorder, first episode of psychosis, and schizophrenia. HDL, its major apolipoprotein component, ApoA1, and the antioxidant enzyme paraoxonase (PON)1 (which is normally bound to ApoA1) all have anti-atherogenic, antioxidant, anti-inflammatory, and immunomodulatory roles, which are discussed in this paper. The paper details the pathways mediating the anti-inflammatory effects of HDL, ApoA1 and PON1 and describes the mechanisms leading to compromised HDL and PON1 levels and function in an environment of chronic inflammation. The molecular mechanisms by which changes in HDL, ApoA1 and PON1 might contribute to the pathophysiology of the neuroprogressive disorders are explained. Moreover, the anti-inflammatory actions of ApoM-mediated sphingosine 1-phosphate (S1P) signalling are reviewed as well as the deleterious effects of chronic inflammation and oxidative stress on ApoM/S1P signalling. Finally, therapeutic interventions specifically aimed at improving the levels and function of HDL and PON1 while reducing levels of inflammation and oxidative stress are considered. These include the so-called Mediterranean diet, extra virgin olive oil, polyphenols, flavonoids, isoflavones, pomegranate juice, melatonin and the Mediterranean diet combined with the ketogenic diet.
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | | | - Chiara C Bortolasci
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia.
| | - Andre Carvalho
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Michael Berk
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Ken Walder
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia
| | - Estefania G Moreira
- Post-Graduation Program in Health Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Michael Maes
- Deakin University, IMPACT - The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, King Chulalongkorn University Hospital, Bangkok, Thailand; Department of Psychiatry, Medical University of Plovdiv, Plovdiv, Bulgaria
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Samuchiwal SK, Balestrieri B. Harmful and protective roles of group V phospholipase A 2: Current perspectives and future directions. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:819-826. [PMID: 30308324 DOI: 10.1016/j.bbalip.2018.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 09/27/2018] [Accepted: 10/01/2018] [Indexed: 12/17/2022]
Abstract
Group V Phospholipase A2 (Pla2g5) is a member of the PLA2 family of lipid-generating enzymes. It is expressed in immune and non-immune cell types and is inducible during several pathologic conditions serving context-specific functions. In this review, we recapitulate the protective and detrimental functions of Pla2g5 investigated through preclinical and translational approaches. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.
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Affiliation(s)
- Sachin K Samuchiwal
- Department of Medicine, Harvard Medical School, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Barbara Balestrieri
- Department of Medicine, Harvard Medical School, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA.
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7
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Targeting white, brown and perivascular adipose tissue in atherosclerosis development. Eur J Pharmacol 2017; 816:82-92. [DOI: 10.1016/j.ejphar.2017.03.051] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/14/2017] [Accepted: 03/23/2017] [Indexed: 12/31/2022]
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8
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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: 4] [Impact Index Per Article: 0.6] [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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9
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Murakami M, Yamamoto K, Miki Y, Murase R, Sato H, Taketomi Y. The Roles of the Secreted Phospholipase A 2 Gene Family in Immunology. Adv Immunol 2016; 132:91-134. [PMID: 27769509 PMCID: PMC7112020 DOI: 10.1016/bs.ai.2016.05.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Within the phospholipase A2 (PLA2) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA2 (sPLA2) enzymes comprise the largest group containing 11 isoforms in mammals. Individual sPLA2s exhibit unique tissue or cellular distributions and enzymatic properties, suggesting their distinct biological roles. Although PLA2 enzymes, particularly cytosolic PLA2 (cPLA2α), have long been implicated in inflammation by driving arachidonic acid metabolism, the precise biological roles of sPLA2s have remained a mystery over the last few decades. Recent studies employing mice gene-manipulated for individual sPLA2s, in combination with mass spectrometric lipidomics to identify their target substrates and products in vivo, have revealed their roles in diverse biological events, including immunity and associated disorders, through lipid mediator-dependent or -independent processes in given microenvironments. In this review, we summarize our current knowledge of the roles of sPLA2s in various immune responses and associated diseases.
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Affiliation(s)
- M Murakami
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan.
| | - K Yamamoto
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Y Miki
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - R Murase
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - H Sato
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Y Taketomi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Pruzanski W, Kopilov J, Kuksis A. Hydrolysis of lipoproteins by sPLA2's enhances mitogenesis and eicosanoid release from vascular smooth muscle cells: Diverse activity of sPLA2's IIA, V and X. Prostaglandins Other Lipid Mediat 2015; 122:64-8. [PMID: 26711221 DOI: 10.1016/j.prostaglandins.2015.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 12/01/2015] [Accepted: 12/08/2015] [Indexed: 11/30/2022]
Abstract
Mitogenesis of Vascular Smooth Muscle Cells (VSMC) plays an important role in atherogenesis. Until recently, the effect of lipid subfractions has not been clarified. Secretory phospholipases A2 (sPLA2's) hydrolyse glycerophospholipids and release pro-inflammatory lyso-lipids, oxidized and non-oxidized fatty acids and isoprostanes. They localize in the vascular wall. We hypothesized that structurally similar sPLA2's may exert different impact on VSMC. The influence of sPLA2's, IIA, V, X, HDL, LDL, and hydrolysis products was tested on mitogenesis of VSMC, i.e., the early effect on the cell membrane phospholipids, and on PGE2 and LTB4 release, i.e., late effect of Cyclooxygenase and 5-lipooxygenase activity in VSMC. Mitogenesis was significantly enhanced by HDL and LDL, and by products of sPLA2 hydrolysis. Hydrolysis of HDL or LDL enhanced mitogenic activity in order V>X>IIA. The release of PGE2 was enhanced by group X sPLA2 and by HDL hydrolyzed by groups V and X. LDL and its hydrolysis products enhanced the release of PGE2 in order X>V>IIA. The release of LTB4 was markedly increased by LDL and HDL, and by hydrolytic products of group V and X, but not group IIA sPLA2. Our study demonstrates a diverse interaction of pro-inflammatory sPLA2's with HDL and LDL affecting both mitogenesis and eicosanoid release from VSMC, therefore potentially enhancing their pro-atherogenic activity.
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Affiliation(s)
- Waldemar Pruzanski
- St. Michael's Hopital, Toronto, Canada; University of Toronto, Toronto, Canada.
| | | | - Arnis Kuksis
- The Banting and Best Department of Medical Research, Toronto, Canada; University of Toronto, Toronto, Canada
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Guijas C, Rodríguez JP, Rubio JM, Balboa MA, Balsinde J. Phospholipase A2 regulation of lipid droplet formation. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1841:1661-71. [PMID: 25450448 DOI: 10.1016/j.bbalip.2014.10.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/02/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023]
Abstract
The classical regard of lipid droplets as mere static energy-storage organelles has evolved dramatically. Nowadays these organelles are known to participate in key processes of cell homeostasis, and their abnormal regulation is linked to several disorders including metabolic diseases (diabetes, obesity, atherosclerosis or hepatic steatosis), inflammatory responses in leukocytes, cancer development and neurodegenerative diseases. Hence, the importance of unraveling the cell mechanisms controlling lipid droplet biosynthesis, homeostasis and degradation seems evident Phospholipase A2s, a family of enzymes whose common feature is to hydrolyze the fatty acid present at the sn-2 position of phospholipids, play pivotal roles in cell signaling and inflammation. These enzymes have recently emerged as key regulators of lipid droplet homeostasis, regulating their formation at different levels. This review summarizes recent results on the roles that various phospholipase A2 forms play in the regulation of lipid droplet biogenesis under different conditions. These roles expand the already wide range of functions that these enzymes play in cell physiology and pathophysiology.
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12
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Murakami M, Sato H, Miki Y, Yamamoto K, Taketomi Y. A new era of secreted phospholipase A₂. J Lipid Res 2015; 56:1248-61. [PMID: 25805806 DOI: 10.1194/jlr.r058123] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Indexed: 12/18/2022] Open
Abstract
Among more than 30 members of the phospholipase A2 (PLA2) superfamily, secreted PLA2 (sPLA2) enzymes represent the largest family, being Ca(2+)-dependent low-molecular-weight enzymes with a His-Asp catalytic dyad. Individual sPLA2s exhibit unique tissue and cellular distributions and enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for nearly a full set of sPLA2 subtypes, in combination with sophisticated lipidomics as well as biochemical and cell biological studies, have revealed distinct contributions of individual sPLA2s to various pathophysiological events, including production of pro- and anti-inflammatory lipid mediators, regulation of membrane remodeling, degradation of foreign phospholipids in microbes or food, or modification of extracellular noncellular lipid components. In this review, we highlight the current understanding of the in vivo functions of sPLA2s and the underlying lipid pathways as revealed by a series of studies over the last decade.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan CREST, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Hiroyasu Sato
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yoshimi Miki
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kei Yamamoto
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yoshitaka Taketomi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
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13
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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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14
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Shridas P, Zahoor L, Forrest KJ, Layne JD, Webb NR. Group X secretory phospholipase A2 regulates insulin secretion through a cyclooxygenase-2-dependent mechanism. J Biol Chem 2014; 289:27410-7. [PMID: 25122761 DOI: 10.1074/jbc.m114.591735] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Group X secretory phospholipase A2 (GX sPLA2) potently hydrolyzes membrane phospholipids to release arachidonic acid (AA). While AA is an activator of glucose-stimulated insulin secretion (GSIS), its metabolite prostaglandin E2 (PGE2) is a known inhibitor. In this study, we determined that GX sPLA2 is expressed in insulin-producing cells of mouse pancreatic islets and investigated its role in beta cell function. GSIS was measured in vivo in wild-type (WT) and GX sPLA2-deficient (GX KO) mice and ex vivo using pancreatic islets isolated from WT and GX KO mice. GSIS was also assessed in vitro using mouse MIN6 pancreatic beta cells with or without GX sPLA2 overexpression or exogenous addition. GSIS was significantly higher in islets isolated from GX KO mice compared with islets from WT mice. Conversely, GSIS was lower in MIN6 cells overexpressing GX sPLA2 (MIN6-GX) compared with control (MIN6-C) cells. PGE2 production was significantly higher in MIN6-GX cells compared with MIN6-C cells and this was associated with significantly reduced cellular cAMP. The effect of GX sPLA2 on GSIS was abolished when cells were treated with NS398 (a COX-2 inhibitor) or L-798,106 (a PGE2-EP3 receptor antagonist). Consistent with enhanced beta cell function, GX KO mice showed significantly increased plasma insulin levels following glucose challenge and were protected from age-related reductions in GSIS and glucose tolerance compared with WT mice. We conclude that GX sPLA2 plays a previously unrecognized role in negatively regulating pancreatic insulin secretion by augmenting COX-2-dependent PGE2 production.
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Affiliation(s)
- Preetha Shridas
- From Saha Cardiovascular Research Center and Departments of Internal Medicine and
| | - Lubna Zahoor
- From Saha Cardiovascular Research Center and Departments of Internal Medicine and
| | - Kathy J Forrest
- From Saha Cardiovascular Research Center and Departments of Internal Medicine and
| | - Joseph D Layne
- From Saha Cardiovascular Research Center and Pharmacology and Nutritional Sciences, Division of Nutritional Sciences, University of Kentucky Medical Center, Lexington Kentucky 40536
| | - Nancy R Webb
- From Saha Cardiovascular Research Center and Pharmacology and Nutritional Sciences, Division of Nutritional Sciences, University of Kentucky Medical Center, Lexington Kentucky 40536
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15
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Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
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Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
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16
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Ait-Oufella H, Herbin O, Lahoute C, Coatrieux C, Loyer X, Joffre J, Laurans L, Ramkhelawon B, Blanc-Brude O, Karabina S, Girard CA, Payré C, Yamamoto K, Binder CJ, Murakami M, Tedgui A, Lambeau G, Mallat Z. Group X Secreted Phospholipase A2 Limits the Development of Atherosclerosis in LDL Receptor–Null Mice. Arterioscler Thromb Vasc Biol 2013; 33:466-73. [DOI: 10.1161/atvbaha.112.300309] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Several secreted phospholipases A2 (sPLA2s), including group IIA, III, V, and X, have been linked to the development of atherosclerosis, which led to the clinical testing of A-002 (varespladib), a broad sPLA2 inhibitor for the treatment of coronary artery disease. Group X sPLA2 (PLA2G10) has the most potent hydrolyzing activity toward phosphatidylcholine and is believed to play a proatherogenic role.
Methods and Results—
Here, we show that
Ldlr
–/–
mice reconstituted with bone marrow from mouse group X–deficient mice (
Pla2g10
–/–
) unexpectedly display a doubling of plaque size compared with
Pla2g10
+/+
chimeric mice. Macrophages of
Pla2g10
–/–
mice are more susceptible to apoptosis in vitro, which is associated with a 4-fold increase of plaque necrotic core in vivo. In addition, chimeric
Pla2g10
–/–
mice show exaggerated T lymphocyte (Th)1 immune response, associated with enhanced T-cell infiltration in atherosclerotic plaques. Interestingly, overexpression of human PLA2G10 in murine bone marrow cells leads to significant reduction of Th1 response and to 50% reduction of lesion size.
Conclusion—
PLA2G10 expression in bone marrow cells controls a proatherogenic Th1 response and limits the development of atherosclerosis. The results may provide an explanation for the recently reported inefficacy of A-002 (varespladib) to treat patients with coronary artery disease. Indeed, A-002 is a nonselective sPLA2 inhibitor that inhibits both proatherogenic (groups IIA and V) and antiatherogenic (group X) sPLA2s. Our results suggest that selective targeting of individual sPLA2 enzymes may be a better strategy to treat cardiovascular diseases.
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Affiliation(s)
- Hafid Ait-Oufella
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Olivier Herbin
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Charlotte Lahoute
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Christelle Coatrieux
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Xavier Loyer
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Jeremie Joffre
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Ludivine Laurans
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Bhama Ramkhelawon
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Olivier Blanc-Brude
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Sonia Karabina
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Christophe A. Girard
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Christine Payré
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Kei Yamamoto
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Christoph J. Binder
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Makoto Murakami
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Alain Tedgui
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Gérard Lambeau
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
| | - Ziad Mallat
- From the Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France (H.A.-O., O.H., C.L., X.L., J.J., L.L., B.R., O.B.-B., A.T., Z.M.); Service de Réanimation Médicale, Hôpital Saint-Antoine, AP-HP, Université Pierre et Marie Curie, Paris, France (H.A.-O.); Institute of Molecular and Cellular Pharmacology (IPMC), UMR 7275 CNRS- and Université de Nice-Sophia Antipolis, Valbonne, France (C.C., C.A.G., C.P., G.L.); Inserm UMRS 937, Paris, France (S.K.); Lipid Metabolism
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17
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Telmisartan and N-acetylcysteine Suppress Group V Secretory Phospholipase A2 Expression in TNFα-stimulated Human Endothelial Cells and Reduce Associated Atherogenicity. J Cardiovasc Pharmacol 2012; 60:367-74. [DOI: 10.1097/fjc.0b013e3182646ccc] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Meyer JM, Ji A, Cai L, van der Westhuyzen DR. High-capacity selective uptake of cholesteryl ester from native LDL during macrophage foam cell formation. J Lipid Res 2012; 53:2081-2091. [PMID: 22833685 PMCID: PMC3435541 DOI: 10.1194/jlr.m026534] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophage foam cells are a defining pathologic feature of atherosclerotic lesions. Recent studies have demonstrated that at high concentrations associated with hypercholesterolemia, native LDL induces macrophage lipid accumulation. LDL particles are taken up by macrophages as part of bulk fluid pinocytosis. However, the uptake and metabolism of cholesterol from native LDL during foam cell formation has not been clearly defined. Previous reports have suggested that selective cholesteryl ester (CE) uptake might contribute to cholesterol uptake from LDL independently of particle endocytosis. In this study we demonstrate that the majority of macrophage LDL-derived cholesterol is acquired by selective CE uptake in excess of LDL pinocytosis and degradation. Macrophage selective CE uptake does not saturate at high LDL concentrations and is not down-regulated during cholesterol accumulation. In contrast to CE uptake, macrophages exhibit little selective uptake of free cholesterol (FC) from LDL. Following selective uptake from LDL, CE is rapidly hydrolyzed by a novel chloroquine-sensitive pathway. FC released from LDL-derived CE hydrolysis is largely effluxed from cells but also is subject to ACAT-mediated reesterification. These results indicate that selective CE uptake plays a major role in macrophage metabolism of LDL.
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Affiliation(s)
- Jason M Meyer
- Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536
| | - Ailing Ji
- Department of Veterans Affairs Medical Center, Lexington, KY 40502; Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536; Barnstable Brown Kentucky Diabetes and Obesity Center, University of Kentucky, Lexington, KY 40536
| | - Lei Cai
- Department of Veterans Affairs Medical Center, Lexington, KY 40502; Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536; Barnstable Brown Kentucky Diabetes and Obesity Center, University of Kentucky, Lexington, KY 40536
| | - Deneys R van der Westhuyzen
- Department of Veterans Affairs Medical Center, Lexington, KY 40502; Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536; Barnstable Brown Kentucky Diabetes and Obesity Center, University of Kentucky, Lexington, KY 40536.
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19
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Potent and selective 2-oxoamide inhibitors of phospholipases A2 as novel medicinal agents for the treatment of inflammatory diseases. PURE APPL CHEM 2012. [DOI: 10.1351/pac-con-11-10-32] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phospholipases A2 (PLA2s) are enzymes that are capable of catalyzing the hydrolysis of the sn-2 ester bond of glycerophospholipids, releasing free fatty acids, including arachidonic acid (AA), and lysophospholipids. Both products are precursor signaling molecules involved in inflammation. Among the various PLA2s, cytosolic GIVA cPLA2 is considered a major target for inflammatory diseases, while secreted GIIA sPLA2 is involved in cardiovascular diseases. We have developed lipophilic 2-oxoamides based on (S)-γ- or δ-amino acids as potent and selective inhibitors of GIVA cPLA2, which present interesting in vivo anti-inflammatory activity. 2-Oxoamides based on natural α-amino acids are selective inhibitors of GIIA sPLA2. The mode of binding of 2-oxoamides with either GIVA cPLA2 or GIIA sPLA2 has been studied by various techniques.
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20
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Phospholipase A(2)-modified low-density lipoprotein activates liver X receptor in human macrophages. Cell Biochem Biophys 2012; 63:143-9. [PMID: 22367754 DOI: 10.1007/s12013-012-9351-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Macrophages respond to cholesterol accumulation by increasing cholesterol efflux, which is mediated by activation of the nuclear liver X receptor (LXR) and ATP binding cassette (ABC) transporters. In the present study, we investigated whether foam cell formation induced by phospholipase A(2)-modified low-density lipoprotein (PLA-LDL) influences LXR activity and cholesterol efflux in primary human monocyte-derived macrophages (MDMs). Macrophages were treated with PLA-LDL and expression of the LXR target genes ABCA1 and ABCG1 was analyzed by quantitative PCR and western blot. PLA-LDL time-dependently up-regulated ABCA1 and ABCG1 mRNA and protein. Removal of non-esterified fatty acids from PLA-LDL particles did not influence the induction of ABC transporters. A role of LXR in PLA-LDL-stimulated ABCG1 expression was verified by LXR-knockdown and luciferase reporter assays using a construct containing a LXR response element from the ABCG1 gene. Functionally, cholesterol efflux to apolipoprotein A-I and high-density lipoprotein was higher in PLA-LDL treated cells compared to controls. Together, these results demonstrate that in primary human MDMs PLA-LDL induces ABC transporter expression via LXR activation. A concomitantly increased cholesterol efflux may prevent excessive cholesterol accumulation and thus, attenuate foam cell formation.
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21
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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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22
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Degousee N, Kelvin DJ, Geisslinger G, Hwang DM, Stefanski E, Wang XH, Danesh A, Angioni C, Schmidt H, Lindsay TF, Gelb MH, Bollinger J, Payré C, Lambeau G, Arm JP, Keating A, Rubin BB. Group V phospholipase A2 in bone marrow-derived myeloid cells and bronchial epithelial cells promotes bacterial clearance after Escherichia coli pneumonia. J Biol Chem 2011; 286:35650-35662. [PMID: 21849511 PMCID: PMC3195628 DOI: 10.1074/jbc.m111.262733] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/11/2011] [Indexed: 02/05/2023] Open
Abstract
Group V-secreted phospholipase A(2) (GV sPLA(2)) hydrolyzes bacterial phospholipids and initiates eicosanoid biosynthesis. Here, we elucidate the role of GV sPLA(2) in the pathophysiology of Escherichia coli pneumonia. Inflammatory cells and bronchial epithelial cells both express GV sPLA(2) after pulmonary E. coli infection. GV(-/-) mice accumulate fewer polymorphonuclear leukocytes in alveoli, have higher levels of E. coli in bronchoalveolar lavage fluid and lung, and develop respiratory acidosis, more severe hypothermia, and higher IL-6, IL-10, and TNF-α levels than GV(+/+) mice after pulmonary E. coli infection. Eicosanoid levels in bronchoalveolar lavage are similar in GV(+/+) and GV(-/-) mice after lung E. coli infection. In contrast, GV(+/+) mice have higher levels of prostaglandin D(2) (PGD(2)), PGF(2α), and 15-keto-PGE(2) in lung and express higher levels of ICAM-1 and PECAM-1 on pulmonary endothelial cells than GV(-/-) mice after lung infection with E. coli. Selective deletion of GV sPLA(2) in non-myeloid cells impairs leukocyte accumulation after pulmonary E. coli infection, and lack of GV sPLA(2) in either bone marrow-derived myeloid cells or non-myeloid cells attenuates E. coli clearance from the alveolar space and the lung parenchyma. These observations show that GV sPLA(2) in bone marrow-derived myeloid cells as well as non-myeloid cells, which are likely bronchial epithelial cells, participate in the regulation of the innate immune response to pulmonary infection with E. coli.
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Affiliation(s)
- Norbert Degousee
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - David J Kelvin
- Division of Experimental Therapeutics, University of Toronto, Toronto, Ontario M5G 2C4, Canada; Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, People's Republic of China
| | - Gerd Geisslinger
- Institut für Klinische Pharmakologie, D-60590, Frankfurt am Main, Germany
| | - David M Hwang
- Department of Pathology, Toronto General Hospital Research Institute of the University Health Network and the Heart and Stroke/Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Eva Stefanski
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Xing-Hua Wang
- Department of Medical Oncology and Hematology, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Ali Danesh
- Division of Experimental Therapeutics, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Carlo Angioni
- Institut für Klinische Pharmakologie, D-60590, Frankfurt am Main, Germany
| | - Helmut Schmidt
- Institut für Klinische Pharmakologie, D-60590, Frankfurt am Main, Germany
| | - Thomas F Lindsay
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Michael H Gelb
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195
| | - James Bollinger
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195
| | - Christine Payré
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice, Sophia Antipolis et Centre National de la Recherche Scientifique, Sophia Antipolis, 06560 Valbonne, France
| | - Gérard Lambeau
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice, Sophia Antipolis et Centre National de la Recherche Scientifique, Sophia Antipolis, 06560 Valbonne, France
| | - Jonathan P Arm
- Division of Rheumatology, Immunology, and Allergy, and Partners Asthma Center, Brigham and Women's Hospital, Boston Massachusetts 02115
| | - Armand Keating
- Department of Medical Oncology and Hematology, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Barry B Rubin
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada.
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Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos G. Phospholipase A2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem Rev 2011; 111:6130-85. [PMID: 21910409 PMCID: PMC3196595 DOI: 10.1021/cr200085w] [Citation(s) in RCA: 804] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Yuan-Hao Hsu
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
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24
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Plihtari R, Kovanen PT, Öörni K. Acidity increases the uptake of native LDL by human monocyte-derived macrophages. Atherosclerosis 2011; 217:401-6. [DOI: 10.1016/j.atherosclerosis.2011.04.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/11/2022]
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25
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Azar M, Valentin E, Badaoui G, Kassab R, Sarkis A, Azar RR. Comparison of the effects of combination atorvastatin (40 mg) + ezetimibe (10 mg) versus atorvastatin (40 mg) alone on secretory phospholipase A2 activity in patients with stable coronary artery disease or coronary artery disease equivalent. Am J Cardiol 2011; 107:1571-4. [PMID: 21439529 DOI: 10.1016/j.amjcard.2011.01.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 01/20/2011] [Accepted: 01/20/2011] [Indexed: 10/18/2022]
Abstract
Secretory phospholipase A2 (sPLA2) is an enzyme that plays an important role in the pathogenesis of atherosclerosis and of adverse cardiovascular events. It is currently the target of emerging therapeutic agents. Our study was designed to investigate the effect of aggressive lowering of low-density lipoprotein (LDL) cholesterol with ezetimibe and atorvastatin on sPLA2 activity. We randomized 100 patients with stable coronary artery disease (CAD) or CAD equivalent (diabetes, stroke, or peripheral vascular disease) to receive ezetimibe 10 mg/day in association with atorvastatin 40 mg/day (combination therapy group) versus atorvastatin 40 mg/day and placebo (monotherapy group). Patients on statin therapy before inclusion were allowed to enter the study as long as the potency of the statin was lower than atorvastatin 40 mg/day. Lipid profile, high-sensitivity C-reactive protein (hs-CRP), and sPLA activity were measured at baseline and after 8 weeks of therapy. The decrease in LDL cholesterol was more significant in the combination therapy group, but the decrease in hs-CRP was similar. sPLA2 activity significantly decreased in the ezetimibe/atorvastatin group from 29 U/ml (interquartile range 23 to 35) to 26 U/ml (23 to 29, p = 0.001) but remained similar in the placebo/atorvastatin group (23 U/ml, 19 to 32, vs 22 U/ml, 19 to 28, p = NS). In a multivariate stepwise linear regression model, change in sPLA2 correlated with change in hs-CRP (p <0.001), baseline LDL cholesterol level (p = 0.001), body mass index (p = 0.003), diabetes mellitus (p = 0.04) and combination therapy with ezetimibe/atorvastatin (p = 0.05). In conclusion, this study demonstrates that coadministration of ezetimibe and atorvastatin decreases sPLA2 activity.
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26
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Yamamoto K, Isogai Y, Sato H, Taketomi Y, Murakami M. Secreted phospholipase A2, lipoprotein hydrolysis, and atherosclerosis: integration with lipidomics. Anal Bioanal Chem 2011; 400:1829-42. [PMID: 21445663 PMCID: PMC3098357 DOI: 10.1007/s00216-011-4864-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 02/14/2011] [Accepted: 03/01/2011] [Indexed: 01/22/2023]
Abstract
Phospholipase A2 (PLA2) is a group of enzymes that hydrolyze the sn-2 position of glycerophospholipids to yield fatty acids and lysophospholipids. Of many PLA2s or related enzymes identified to date, secreted PLA2s (sPLA2s) comprise the largest family that contains 10 catalytically active isozymes. Besides arachidonic acid released from cellular membranes for eicosanoid synthesis, several if not all sPLA2s have recently been implicated in hydrolysis of phospholipids in lipoprotein particles. The sPLA2-processed low-density lipoprotein (LDL) particles contain a large amount of lysophospholipids and exhibit the property of “small-dense” or “modified” LDL, which facilitates foam cell formation from macrophages. Transgenic overexpression of these sPLA2s leads to development of atherosclerosis in mice. More importantly, genetic deletion or pharmacological inhibition of particular sPLA2s significantly attenuates atherosclerosis and aneurysm. In this article, we will give an overview of current understanding of the role of sPLA2s in atherosclerosis, with recent lipidomics data showing the action of a subset of sPLA2s on lipoprotein phospholipids.
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Affiliation(s)
- Kei Yamamoto
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
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27
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Korkmaz L, Erkuş E, Kırış A, Ağaç MT, Acar Z, Turan T, Erkan H, Dursun I, Çelik Ş. Lipoprotein phospholipase A2 in patients with isolated coronary artery ectasia. Clin Res Cardiol 2011; 100:511-4. [DOI: 10.1007/s00392-010-0274-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 12/17/2010] [Indexed: 10/18/2022]
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28
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Mallat Z, Lambeau G, Tedgui A. Lipoprotein-associated and secreted phospholipases A₂ in cardiovascular disease: roles as biological effectors and biomarkers. Circulation 2010; 122:2183-200. [PMID: 21098459 DOI: 10.1161/circulationaha.110.936393] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Ziad Mallat
- INSERM, Paris-Cardiovascular Research Center, Université Paris Descartes, UMR, Paris, France
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29
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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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30
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Friend Turns Foe: Transformation of Anti-Inflammatory HDL to Proinflammatory HDL during Acute-Phase Response. CHOLESTEROL 2010; 2011:274629. [PMID: 21490770 PMCID: PMC3065911 DOI: 10.1155/2011/274629] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 11/01/2010] [Indexed: 01/09/2023]
Abstract
High-density lipoprotein (HDL) is a major carrier of cholesterol in the blood. Unlike other lipoproteins, physiological functions of HDL influence the cardiovascular system in favorable ways except when HDL is modified pathologically. The cardioprotective mechanism of HDL is mainly based on reverse cholesterol transport, but there has been an emerging interest in the anti-inflammatory and antioxidant roles of HDL. These latter activities of HDL are compromised in many pathological states associated with inflammation. Further, abnormal HDL can become proinflammatory contributing to oxidative damage. In this paper, we discuss the functional heterogeneity of HDL, how alterations in these particles in inflammatory states result in loss of both antioxidant activity and reverse cholesterol transport in relation to atherosclerosis, and the need for assays to predict its functionality.
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31
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Rosenson RS, Hislop C, Elliott M, Stasiv Y, Goulder M, Waters D. Effects of varespladib methyl on biomarkers and major cardiovascular events in acute coronary syndrome patients. J Am Coll Cardiol 2010; 56:1079-88. [PMID: 20863951 DOI: 10.1016/j.jacc.2010.06.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 05/19/2010] [Accepted: 06/01/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The purpose of this study was to investigate the effects of varespladib on cardiovascular biomarkers in acute coronary syndrome patients. BACKGROUND Secretory phospholipase A(2) (sPLA(2)) represents a family of proatherogenic enzymes that hydrolyze lipoprotein phospholipids, increasing their affinity for intimal proteoglycans; contribute to cholesterol loading of macrophages by nonscavenger receptor mediated pathways; and activate inflammatory pathways. In prospective studies, high sPLA(2)-IIA levels predicted major adverse cardiovascular events in acute coronary syndrome (ACS) and stable coronary heart disease patients. METHODS This randomized, double-blind, prospective controlled clinical trial (phase 2B) was designed to investigate the effects of sPLA(2) inhibition with varespladib 500 mg daily versus placebo as adjunctive therapy to atorvastatin 80 mg daily on biomarkers (low-density lipoprotein cholesterol [LDL-C], high-sensitivity C-reactive protein [hsCRP], and sPLA(2)-IIA levels), major adverse cardiovascular events (unstable angina, myocardial infarction, death), and safety. In all, 625 ACS subjects were randomized within 96 h of the index event and treated for a minimum of 6 months. RESULTS After 8 weeks (primary efficacy end point), varespladib/atorvastatin reduced mean LDL-C levels from baseline by 49.6% compared with 43.4% with placebo/atorvastatin (p = 0.002). Respective 8-week median reductions in sPLA(2)-IIA levels were 82.4% and 15.6% (p < 0.0001), and hsCRP levels were lowered by 75.0% and 71.0% (p = 0.097). At 24 weeks, respective reductions with varespladib and placebo were as follows: LDL-C 43.5% versus 37.6% (p < 0.05), hsCRP 79.8% versus 77.0% (p = 0.02), and sPLA(2)-IIA 78.5% versus 6.4% (p < 0.0001). Major adverse cardiovascular events were not different from placebo 6 months post-randomization (7.3% varespladib vs. 7.7% placebo). No treatment differences in elevated liver function studies on >1 occasion were observed. CONCLUSIONS Varespladib therapy effectively reduced LDL-C and inflammatory biomarkers in ACS patients treated with conventional therapy including atorvastatin 80 mg daily. There were no treatment differences in clinical cardiovascular events. (FRANCIS [Fewer Recurrent Acute Coronary Events With Near-Term Cardiovascular Inflammation Suppression]-ACS Trial: A Study of the Safety and Efficacy of A 002 in Subjects With Acute Coronary Syndromes; NCT00743925).
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32
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Pioglitazone suppresses the lipopolysaccharide-induced production of inflammatory factors in mouse macrophages by inactivating NF-kappaB. Cell Biol Int 2010; 34:723-30. [PMID: 19947950 DOI: 10.1042/cbi20090005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TZDs (thiazolidinediones) are prescribed as anti-Type II diabetes drugs, but little is known regarding whether TZDs regulate the expression of sPLA2 (secretory phospholipase A2) in macrophages. We have investigated the effects of pioglitazone on LPS (lipopolysaccharide)-induced production of TNF-alpha (tumour necrosis factor alpha), sPLA2-V and -X (groups V and X sPLA2) in RAW 264.7 macrophages. TNF-alpha, sPLA2-V and -X mRNA and protein expression were determined by RT-PCR (reverse transcriptase-PCR) and Western blot analysis, respectively. The activity of NF-kappaB (nuclear factor kappaB) was determined by Western blot and confocal microscopy. LPS induced TNF-alpha, sPLA2-V and sPLA2-X mRNA and protein expression. Pretreatment with 10 mumol/l pioglitazone significantly suppressed LPS-induced TNF-alpha, sPLA2-V and sPLA2-X mRNA and protein expression. LPS induced NF-kappaB expression and translocation in the nucleus, but the inductive effects were inhibited by pioglitazone. Our findings indicate that pioglitazone inhibits production of inflammatory factors induced by LPS in murine macrophage cells by inactivating NF-kappaB. Pioglitazone appears to play an anti-inflammatory role in the atherosclerotic process.
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33
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Varespladib (A-002), a secretory phospholipase A2 inhibitor, reduces atherosclerosis and aneurysm formation in ApoE-/- mice. J Cardiovasc Pharmacol 2010; 53:60-5. [PMID: 19129734 DOI: 10.1097/fjc.0b013e318195bfbc] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The family of secretory phospholipase A2 (sPLA2) enzymes has been associated with inflammatory diseases and tissue injury including atherosclerosis. A-001 is a novel inhibitor of sPLA2 enzymes discovered by structure-based drug design, and A-002 is the orally bioavailable prodrug currently in clinical development. A-001 inhibited human and mouse sPLA2 group IIA, V, and X enzymes with IC50 values in the low nM range. A-002 (1 mg/kg) led to high serum levels of A-001 and inhibited PLA2 activity in transgenic mice overexpressing human sPLA2 group IIA in C57BL/6J background. In addition, the effects of A-002 on atherosclerosis in 2 ApoE mouse models were evaluated using en face analysis. (1) In a high-fat diet model, A-002 (30 and 90 mg/kg twice a day for 16 weeks) reduced aortic atherosclerosis by 50% (P < 0.05). Plasma total cholesterol was decreased (P < 0.05) by 1 month and remained lowered throughout the study. (2) In an accelerated atherosclerosis model, with angiotensin II-induced aortic lesions and aneurysms, A-002 (30 mg/kg twice a day) reduced aortic atherosclerosis by approximately 40% (P < 0.05) and attenuated aneurysm formation (P = 0.0096). Thus, A-002 was effective at significantly decreasing total cholesterol, atherogenesis, and aneurysm formation in these 2 ApoE mouse models.
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34
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Extracellular phospholipases in atherosclerosis. Biochimie 2010; 92:594-600. [DOI: 10.1016/j.biochi.2010.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/02/2010] [Indexed: 01/01/2023]
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35
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Meddad-Belhabich N, Aoun D, Djimdé A, Redeuilh C, Dive G, Massicot F, Chau F, Heymans F, Lamouri A. Design of new potent and selective secretory phospholipase A2 inhibitors. 6-Synthesis, structure–activity relationships and molecular modelling of 1-substituted-4-[4,5-dihydro-1,2,4-(4H)-oxadiazol-5-one-3-yl(methyl)]-functionalized aryl piperazin/one/dione derivatives. Bioorg Med Chem 2010; 18:3588-600. [DOI: 10.1016/j.bmc.2010.03.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 03/20/2010] [Indexed: 11/28/2022]
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36
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Gora S, Maouche S, Atout R, Wanherdrick K, Lambeau G, Cambien F, Ninio E, Karabina SA. Phospholipolyzed LDL induces an inflammatory response in endothelial cells through endoplasmic reticulum stress signaling. FASEB J 2010; 24:3284-97. [PMID: 20430794 DOI: 10.1096/fj.09-146852] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Secreted phospholipases A2 (sPLA2s) are present in atherosclerotic plaques and are now considered novel attractive therapeutic targets and potential biomarkers as they contribute to the development of atherosclerosis through lipoprotein-dependent and independent mechanisms. We have previously shown that hGX-sPLA2-phospholipolyzed LDL (LDL-X) induces proinflammatory responses in human umbilical endothelial cells (HUVECs); here we explore the molecular mechanisms involved. Global transcriptional gene expression profiling of the response of endothelial cells exposed to either LDL or LDL-X revealed that LDL-X activates multiple distinct cellular pathways including the unfolded protein response (UPR). Mechanistic insight showed that LDL-X activates UPR through calcium depletion of intracellular stores, which in turn disturbs cytoskeleton organization. Treatment of HUVECs and aortic endothelial cells (HAECs) with LDL-X led to activation of all 3 proximal initiators of UPR: eIF-2alpha, IRE1alpha, and ATF6. In parallel, we observed a sustained phosphorylation of the p38 pathway resulting in the phosphorylation of AP-1 downstream targets. This was accompanied by significant production of the proinflammatory cytokines IL-6 and IL-8. Our study demonstrates that phospholipolyzed LDL uses a range of molecular pathways including UPR to initiate endothelial cell perturbation and thus provides an LDL oxidation-independent mechanism for the initiation of vascular inflammation in atherosclerosis.
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Affiliation(s)
- Sarah Gora
- INSERM UMRS 937, Université Pierre et Marie Curie, UPMC-Paris 6, Paris, France
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37
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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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Boyanovsky BB, Li X, Shridas P, Sunkara M, Morris AJ, Webb NR. Bioactive products generated by group V sPLA(2) hydrolysis of LDL activate macrophages to secrete pro-inflammatory cytokines. Cytokine 2010; 50:50-7. [PMID: 20138782 DOI: 10.1016/j.cyto.2009.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 12/16/2009] [Accepted: 12/18/2009] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Previous studies have established that hydrolysis of LDL by Group V secretory phospholipase A(2) (GV sPLA(2)) generates a modified particle capable of inducing macrophage foam cell formation. The aim of the present study was to determine whether GV sPLA(2)-hydrolyzed LDL (GV-LDL) produces pro-atherogenic effects in macrophages independent of cholesterol accumulation. METHODS AND RESULTS J-774 cells incubated with GV-LDL produced more TNF-alpha and IL-6 compared to cells incubated with control-LDL. Indirect immunofluorescence showed that GV-LDL but not control-LDL induced nuclear translocation of NFkappaB. Inhibitors of NFkappaB activation, effectively blocked cytokine production induced by GV-LDL. Control-LDL and GV-LDL were separated from albumin present in reaction mixtures by ultracentrifugation. The albumin fraction derived from GV-LDL contained 80% of the FFA generated and was more potent than the re-isolated GV-LDL in inducing pro-inflammatory cytokine secretion. Linoleic acid (18:2) and oleic acid (18:1) were the most abundant FFAs generated, whereas newly formed lyso-PCs contained 14:0 (myristic), 16:1 (palmitic), and 18:2 fatty acyl groups. Experiments with synthetic FFA showed that 18:1 induced J-774 cells to secrete TNF-alpha and IL-6. CONCLUSIONS These results indicate that in addition to promoting atherosclerotic lipid accumulation in macrophages, GV sPLA(2) hydrolysis of LDL leads to activation of NFkappaB, a key regulator of inflammation.
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Affiliation(s)
- Boris B Boyanovsky
- Department of Internal Medicine Endocrinology Division, University of Kentucky, Lexington, 40536, USA.
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40
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Namgaladze D, Morbitzer D, von Knethen A, Brüne B. Phospholipase A
2
–Modified Low-Density Lipoprotein Activates Macrophage Peroxisome Proliferator–Activated Receptors. Arterioscler Thromb Vasc Biol 2010; 30:313-20. [DOI: 10.1161/atvbaha.109.199232] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Dmitry Namgaladze
- From Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I/ZAFES, Frankfurt, Germany (D.N., D.M., A.v.K., and B.B.)
| | - Daniel Morbitzer
- From Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I/ZAFES, Frankfurt, Germany (D.N., D.M., A.v.K., and B.B.)
| | - Andreas von Knethen
- From Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I/ZAFES, Frankfurt, Germany (D.N., D.M., A.v.K., and B.B.)
| | - Bernhard Brüne
- From Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I/ZAFES, Frankfurt, Germany (D.N., D.M., A.v.K., and B.B.)
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41
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Plihtari R, Hurt-Camejo E, Oörni K, Kovanen PT. Proteolysis sensitizes LDL particles to phospholipolysis by secretory phospholipase A2 group V and secretory sphingomyelinase. J Lipid Res 2010; 51:1801-9. [PMID: 20124257 DOI: 10.1194/jlr.m003103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
LDL particles that enter the arterial intima become exposed to proteolytic and lipolytic modifications. The extracellular hydrolases potentially involved in LDL modification include proteolytic enzymes, such as chymase, cathepsin S, and plasmin, and phospholipolytic enzymes, such as secretory phospholipases A2 (sPLA2-IIa and sPLA2-V) and secretory acid sphingomyelinase (sSMase). Here, LDL was first proteolyzed and then subjected to lipolysis, after which the effects of combined proteolysis and lipolysis on LDL fusion and on binding to human aortic proteoglycans (PG) were studied. Chymase and cathepsin S led to more extensive proteolysis and release of peptide fragments from LDL than did plasmin. sPLA2-IIa was not able to hydrolyze unmodified LDL, and even preproteolysis of LDL particles failed to enhance lipolysis by this enzyme. However, preproteolysis with chymase and cathepsin S accelerated lipolysis by sPLA2-V and sSMase, which resulted in enhanced fusion and proteoglycan binding of the preproteolyzed LDL particles. Taken together, the results revealed that proteolysis sensitizes the LDL particles to hydrolysis by sPLA2-V and sSMase. By promoting fusion and binding of LDL to human aortic proteoglycans, the combination of proteolysis and phospholipolysis of LDL particles potentially enhances extracellular accumulation of LDL-derived lipids during atherogenesis.
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Ishikawa Y, Kimura-Matsumoto M, Murakami M, Murakami M, Yamamoto K, Akasaka Y, Uzuki M, Yuri Y, Inomata N, Yokoo T, Ishii T. Distribution of smooth muscle cells and macrophages expressing scavenger receptor BI/II in atherosclerosis. J Atheroscler Thromb 2009; 16:829-39. [PMID: 20032583 DOI: 10.5551/jat.1941] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM Scavenger receptors type I and II (SRBI/II) have dual roles in both atherogenic and antiatherogenic functions through interactions with lipoproteins and their expression in macrophages; how-ever, the distribution and density of SRBI/II-positive macrophages and smooth muscle cells (SMCs) as well as their association with lipid metabolism-related proteins in atherosclerotic intima of the human aorta remain unclear. METHODS Autopsied aortic tissues were double-immunostained with SRBI/BII and smooth muscle actin or macrophage-specific antibodies. The density of SRBI/BII-positive SMCs and macrophages in intimal lesion was measured. They were also immunostained with antibodies against four apolipoproteins, four phospholipase A2s, and CETP. RESULTS SRBI/II was expressed in both macrophages and SMCs distributed in various intimal lesions. The density of SRBI/II-positive SMCs in intimal lesions significantly decreased with the advance of atherosclerosis, whereas the density of SRBI/II-positive macrophages significantly increased with atherosclerotic development. In addition, functional proteins, such as apolipoproteins, secretory phospholipase A2s, and CETP, were distributed in the intimal stroma around SRBI/II-positive cells in all lesion types. CONCLUSION The results indicated that SMCs are involved in lipid metabolism via SRBI/II expression mainly in the early stages of atherosclerosis evolution, and that SRBI/II-positive macrophages are mainly involved in advanced stages.
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Affiliation(s)
- Yukio Ishikawa
- Department of Pathology, Toho University School of Medicine, Tokyo, Japan.
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Magrioti V, Kokotos G. Phospholipase A2inhibitors as potential therapeutic agents for the treatment of inflammatory diseases. Expert Opin Ther Pat 2009; 20:1-18. [DOI: 10.1517/13543770903463905] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Phospholipase A2-modified LDL particles retain the generated hydrolytic products and are more atherogenic at acidic pH. Atherosclerosis 2009; 207:352-9. [DOI: 10.1016/j.atherosclerosis.2009.04.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 04/20/2009] [Accepted: 04/28/2009] [Indexed: 11/21/2022]
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Oörni K, Kovanen PT. Lipoprotein modification by secretory phospholipase A(2) enzymes contributes to the initiation and progression of atherosclerosis. Curr Opin Lipidol 2009; 20:421-7. [PMID: 19593123 DOI: 10.1097/mol.0b013e32832fa14d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE OF REVIEW Secretory phospholipase A2s (sPLA2s) are considered to be important enzymes in the initiation and progression of atherosclerosis. In this review, we discuss the various mechanisms by which the direct action of the sPLA2s on LDL particles in the arterial intima may contribute to atherogenesis. RECENT FINDINGS A wealth of evidence, both in vitro and in vivo, supports a role for the sPLA2s in atherogenesis. Very recently, systemic inhibition of sPLA2s was found to reduce measures of arterial inflammation. The mechanisms behind this inhibition, however, are largely unknown. Here, we discuss the consequences of sPLA2 action on LDL in the arterial intima and address the recent findings regarding the effects of the lipolytic products of sPLA2, lysophosphatidylcholine, and fatty acids on intimal cells. LDL modified by sPLA2 can accumulate in the arterial intima both extracellularly and intracellularly. Importantly, the lipolytic products promote atherosclerosis by monocyte/macrophage recruitment, by enhancing the production of proretentive molecules by vascular smooth muscle cells, and by inducing cell death. SUMMARY Recent findings on sPLA2s support the idea that the enzymes contribute to human atherogenesis not only as initiating agents but also in maintaining plaque inflammation.
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Abstract
PURPOSE OF REVIEW As the role of lipids and inflammation in the genesis and progression of the atherosclerosis disease is unquestionable, novel treatment modalities that target both aspects are currently under investigation. RECENT FINDINGS For a long time atherosclerosis was regarded as a lipid-driven disease, but now it is evident that it also involves the simultaneous and combined effect of inflammation and immunological pathways. The secreted PLA2s and the lipoprotein-associated phospholipase A2 (Lp-PLA2) have been associated with atherogenesis and its complications. These two enzymes produce biologically active metabolites that are involved in several phases of the atherosclerosis process. SUMMARY In animal, pathological and epidemiological studies, the increased levels of these two phospholipases (i.e. PLA2s and Lp-PLA2) have been related with an increase in complex coronary lesions and increase in major cardiovascular clinical events, respectively. Therefore, inhibition of these enzymes has become the focus of research in this last decennium. Novel pharmacological inhibitors of those enzymes such as darapladib and varespladib emerge as promising therapeutical options for treating patients with coronary artery disease. Ongoing mechanistic and clinical outcome trials will further elucidate their role in this context.
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Molecular and functional characterization of polymorphisms in the secreted phospholipase A2 group X gene: relevance to coronary artery disease. J Mol Med (Berl) 2009; 87:723-33. [PMID: 19495570 PMCID: PMC2700867 DOI: 10.1007/s00109-009-0483-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 04/17/2009] [Accepted: 04/29/2009] [Indexed: 01/21/2023]
Abstract
Among secreted phospholipases A2 (sPLA2s), human group X sPLA2 (hGX sPLA2) is emerging as a novel attractive therapeutic target due to its implication in inflammatory diseases. To elucidate whether hGX sPLA2 plays a causative role in coronary artery disease (CAD), we screened the human PLA2G10 gene to identify polymorphisms and possible associations with CAD end-points in a prospective study, AtheroGene. We identified eight polymorphisms, among which, one non-synonymous polymorphism R38C in the propeptide region of the sPLA2. The T-512C polymorphism located in the 5' untranslated region was associated with a decreased risk of recurrent cardiovascular events during follow-up. The functional analysis of the R38C polymorphism showed that it leads to a profound change in expression and activity of hGX sPLA2, although there was no detectable impact on CAD risk. Due to the potential role of hGX sPLA2 in inflammatory processes, these polymorphisms should be investigated in other inflammatory diseases.
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Fujioka D, Kugiyama K. Novel Insights of Secretory Phospholipase A2 Action in Cardiology. Trends Cardiovasc Med 2009; 19:100-3. [DOI: 10.1016/j.tcm.2009.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Rosenson RS, Hislop C, McConnell D, Elliott M, Stasiv Y, Wang N, Waters DD. Effects of 1-H-indole-3-glyoxamide (A-002) on concentration of secretory phospholipase A2 (PLASMA study): a phase II double-blind, randomised, placebo-controlled trial. Lancet 2009; 373:649-58. [PMID: 19231633 DOI: 10.1016/s0140-6736(09)60403-7] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Secretory phospholipase A(2) (sPLA(2)) enzymes, produced and secreted in human blood vessels and hepatocytes, contribute to the development of atherosclerosis through mechanisms that are both dependent and independent of lipoprotein. We examined the effects of an sPLA(2) inhibitor on enzyme concentration and on plasma lipoproteins and inflammatory biomarkers in patients with coronary heart disease. METHODS Patients aged 18 years and older with stable coronary heart disease from the USA and Ukraine were eligible for enrolment in this phase II, randomised, double-blind, placebo-controlled, parallel-arm, dose-response study. 393 patients were randomly assigned by computer-generated sequence to receive either placebo (n=79) or one of four doses of an sPLA(2) inhibitor, A-002 (1-H-indole-3-glyoxamide; 50 mg [n=79], 100 mg [n=80], 250 mg [n=78], or 500 mg [n=77] twice daily), for 8 weeks. The primary endpoint was the change in sPLA(2) group IIA (sPLA(2)-IIA) concentration or activity from baseline to week 8. Analysis was by modified intention to treat (ITT). The ITT population consisted of all patients who received one dose of study treatment; data for patients who dropped out before the end of the study were carried forward from last observation. This trial is registered with ClinicalTrials.gov, number NCT00455546. FINDINGS All randomised patients received at least one dose and were included in the ITT population. Data for 45 patients were carried forward from last observation (36 in the A-002 group and nine in the placebo group); the main reason for dropout before completion was because of adverse events. 348 patients reached the primary endpoint (A-002 n=278, placebo n=70). Mean sPLA(2)-IIA concentration fell by 86.7%, from 157 pmol/L to 21 [corrected] pmol/L, in the overall active treatment group, and by 4.8%, from 157 pmol/L to 143 [corrected] pmol/L, in the placebo group (p<0.0001 treatment vs placebo). The reductions in sPLA(2)-IIA concentration in the A-002 groups were dose dependent (ranging from 69.2% in the 50 mg group to 95.8% in the 500 mg group) and differed significantly from placebo (p<0.0001 for all doses). In the 500 mg A-002 treatment group, there was one serious adverse event (exacerbation of underlying chronic obstructive pulmonary disease), but the proportion of patients reporting treatment-emergent adverse events did not differ from placebo. The main side-effects of the drug included headache (n=20), nausea (n=17), and diarrhoea (n=12). INTERPRETATION The reductions in sPLA(2)-IIA concentration suggest that A-002 might be an effective anti-atherosclerotic agent.
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Affiliation(s)
- Robert S Rosenson
- Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
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