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Niu W, Vu T, Du G, Bogdanov M, Zheng L. Lysophospholipid remodeling mediated by the LplT and Aas protein complex in the bacterial envelope. J Biol Chem 2024; 300:107704. [PMID: 39173951 PMCID: PMC11416262 DOI: 10.1016/j.jbc.2024.107704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 08/24/2024] Open
Abstract
Lysophospholipid transporter LplT and acyltransferase Aas consist of a lysophospholipid-remodeling system ubiquitously found in gram-negative microorganisms. LplT flips lysophospholipid across the inner membrane which is subsequently acylated by Aas on the cytoplasmic membrane surface. Our previous study showed that the proper functioning of this system is important to protecting Escherichia coli from phospholipase-mediated host attack by maintaining the integrity of the bacterial cell envelope. However, the working mechanism of this system is still unclear. Herein, we report that LplT and Aas form a membrane protein complex in E. coli which allows these two enzymes to cooperate efficiently to move lysophospholipids across the bacterial membrane and catalyze their acylation. The direct interaction of LplT and Aas was demonstrated both in vivo and in vitro with a binding affinity of 2.3 μM. We found that a cytoplasmic loop of LplT adjacent to the exit of the substrate translocation pathway plays an important role in maintaining its interaction with Aas. Aas contains an acyl-acyl carrier protein synthase domain and an acyl-transferase domain. Its interaction with LplT is mediated exclusively by its transferase domain. Mutations within the three loops near the putative catalytic site of the transferase domain, respectively, disrupt its interaction with LplT and lysophospholipid acylation activity. These results support a hypothesis of the functional coupling mechanism, in which LplT directly interacts with the transferase domain of Aas for specific substrate membrane migration, providing synchronization of substrate translocation and biosynthetic events.
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Affiliation(s)
- Wei Niu
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Trung Vu
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Guangwei Du
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Lei Zheng
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA.
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2
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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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3
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Miki Y, Taketomi Y, Kidoguchi Y, Yamamoto K, Muramatsu K, Nishito Y, Park J, Hosomi K, Mizuguchi K, Kunisawa J, Soga T, Boilard E, B. Gowda SG, Ikeda K, Arita M, Murakami M. Group IIA secreted phospholipase A2 controls skin carcinogenesis and psoriasis by shaping the gut microbiota. JCI Insight 2022; 7:152611. [PMID: 35076024 PMCID: PMC8855835 DOI: 10.1172/jci.insight.152611] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/01/2021] [Indexed: 12/22/2022] Open
Abstract
Besides promoting inflammation by mobilizing lipid mediators, group IIA secreted phospholipase A2 (sPLA2-IIA) prevents bacterial infection by degrading bacterial membranes. Here, we show that, despite the restricted intestinal expression of sPLA2-IIA in BALB/c mice, its genetic deletion leads to amelioration of cancer and exacerbation of psoriasis in distal skin. Intestinal expression of sPLA2-IIA is reduced after treatment with antibiotics or under germ-free conditions, suggesting its upregulation by gut microbiota. Metagenome, transcriptome, and metabolome analyses have revealed that sPLA2-IIA deficiency alters the gut microbiota, accompanied by notable changes in the intestinal expression of genes related to immunity and metabolism, as well as in the levels of various blood metabolites and fecal bacterial lipids, suggesting that sPLA2-IIA contributes to shaping of the gut microbiota. The skin phenotypes in Pla2g2a–/– mice are lost (a) when they are cohoused with littermate WT mice, resulting in the mixing of the microbiota between the genotypes, or (b) when they are housed in a more stringent pathogen-free facility, where Pla2g2a expression in WT mice is low and the gut microbial compositions in both genotypes are nearly identical. Thus, our results highlight a potentially new aspect of sPLA2-IIA as a modulator of gut microbiota, perturbation of which affects distal skin responses.
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Affiliation(s)
- Yoshimi Miki
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo (UTokyo), Tokyo, Japan
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science (TMIMS), 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 (UTokyo), Tokyo, Japan
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science (TMIMS), Tokyo, Japan
| | - Yuh Kidoguchi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science (TMIMS), Tokyo, Japan
- School of Science and Engineering, Tokyo Denki University, Saitama, Japan
| | - Kei Yamamoto
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science (TMIMS), Tokyo, Japan
- Division of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Kazuaki Muramatsu
- School of Science and Engineering, Tokyo Denki University, Saitama, Japan
| | | | - Jonguk Park
- Artificial Intelligence Center for Health and Biomedical Research and
| | - Koji Hosomi
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Osaka, Japan
| | - Kenji Mizuguchi
- Artificial Intelligence Center for Health and Biomedical Research and
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Jun Kunisawa
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Osaka, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Eric Boilard
- Centre de Recherche du CHU de Québec, Centre de Recherche Arthrite de l’Université Laval, Department of Microbiology and Immunology, Québec, Canada
| | | | - Kazutaka Ikeda
- Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, Japan
| | - Makoto Arita
- Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, Japan
- Division of Physiological Chemistry and Metabolism, Graduate School of Pharmaceutical Sciences, Keio University, Tokyo, Japan
| | - Makoto Murakami
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo (UTokyo), Tokyo, Japan
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science (TMIMS), Tokyo, Japan
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4
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Kitsiouli E, Tenopoulou M, Papadopoulos S, Lekka ME. Phospholipases A2 as biomarkers in ARDS. Biomed J 2021; 44:663-670. [PMID: 34478892 PMCID: PMC8847824 DOI: 10.1016/j.bj.2021.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 07/16/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a multifactorial life-threatening lung injury, characterized by diffuse lung inflammation and increased alveolocapillary barrier permeability. The different stages of ARDS have distinctive biochemical and clinical profiles. Despite the progress of our understanding on ARDS pathobiology, the mechanisms underlying its pathogenesis are still obscure. Herein, we review the existing literature about the implications of phospholipases 2 (PLA2s), a large family of enzymes that catalyze the hydrolysis of fatty acids at the sn-2 position of glycerophospholipids, in ARDS-related pathology. We emphasize on the versatile way of participation of different PLA2s isoforms in the distinct ARDS subgroup phenotypes by either potentiating lung inflammation and damage or by preserving the normal lung. Current research supports that PLA2s are associated with the progression and the outcome of ARDS. We herein discuss the transcellular communication of PLA2s through secreted extracellular vesicles and suggest it as a new mechanism of PLA2s involvement in ARDS. Thus, the elucidation of the spatiotemporal features of PLA2s expression may give new insights and provide valuable information about the risk of an individual to develop ARDS or advance to more severe stages, and potentially identify PLA2 isoforms as biomarkers and target for pharmacological intervention.
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Affiliation(s)
- Eirini Kitsiouli
- Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Margarita Tenopoulou
- Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Stylianos Papadopoulos
- Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Marilena E Lekka
- Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece.
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5
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van Hensbergen VP, Wu Y, van Sorge NM, Touqui L. Type IIA Secreted Phospholipase A2 in Host Defense against Bacterial Infections. Trends Immunol 2020; 41:313-326. [PMID: 32151494 DOI: 10.1016/j.it.2020.02.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 12/13/2022]
Abstract
The enzyme type IIA secreted phospholipase A2 (sPLA2-IIA) is crucial for mammalian innate host defense against bacterial pathogens. Most studies have investigated the role of sPLA2-IIA in systemic bacterial infections, identifying molecular pathways of bacterial resistance against sPLA2-IIA-mediated killing, and providing insight into sPLA2-IIA mechanisms of action. Sensitization of (antibiotic-resistant) bacteria to sPLA2-IIA action by blocking bacterial resistance or by applying sPLA2-IIA to treat bacterial infections might represent a therapeutic option in the future. Because sPLA2-IIA is highly expressed at mucosal barriers, we also discuss how sPLA2-IIA is likely to be an important driver of microbiome composition; we anticipate that future research in this area may bring new insights into the role of sPLA2-IIA in health and disease.
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Affiliation(s)
- Vincent P van Hensbergen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Yongzheng Wu
- Unité de Biologie Cellulaire de l'infection Microbienne, CNRS UMR3691, Institut Pasteur, Paris, France
| | - Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
| | - Lhousseine Touqui
- Mucoviscidose et Bronchopathies Chroniques, département Santé Globale; Pasteur Institute, Paris, France.
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6
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Brenes H, Loría GD, Lomonte B. Potent virucidal activity against Flaviviridae of a group IIA phospholipase A 2 isolated from the venom of Bothrops asper. Biologicals 2019; 63:48-52. [PMID: 31839332 DOI: 10.1016/j.biologicals.2019.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/20/2019] [Accepted: 12/08/2019] [Indexed: 10/25/2022] Open
Abstract
Secreted phospholipase A2 (sPLA2) molecules are small, calcium-dependent enzymes involved in many biological processes. Viperid venoms possess gIIA sPLA2s and sPLA2-like proteins, both having homology to human gIIA sPLA2, an innate immunity enzyme. We evaluated the antiviral action of Mt-I (catalytically-active sPLA2) and Mt-II (catalytically-inactive variant) isolated from the venom of Bothrops asper, against a diverse group of viruses. Yellow Fever and Dengue (enveloped) viruses were highly susceptible to inactivation by the snake proteins, in contrast to Sabin (non-enveloped; Polio vaccine strain), and Influenza A, Herpes simplex 1 and 2, and Vesicular Stomatitis (enveloped) viruses. Titration of the antiviral effect against Dengue virus revealed Mt-I to be highly potent (IC50 0.5-2 ng/mL), whereas Mt-II was 1000-fold weaker. This large difference suggested a requirement for PLA2 activity, which was confirmed by chemical inactivation of Mt-I. A synthetic peptide representing the membrane-disrupting region of Mt-II, previously shown to have bactericidal effect, lacked antiviral action, suggesting that the weak virucidal effect observed for Mt-II is likely caused by contamination with traces of Mt-I. On the other hand, Mt-I was demonstrated to act by a direct virucidal mechanism prior to infection, and not by an independent effect on host cells, either pretreated, or exposed to Mt-I after virus infection. Interestingly, DENV2 propagated in mosquito cells was much more sensitive to the action of Mt-I, compared to human cell-propagated virus. Therefore, differences in envelope membrane composition may be crucially involved in the observed virucidal action of PLA2 enzymes.
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Affiliation(s)
- Hebleen Brenes
- Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud (INCIENSA), Tres Ríos, Cartago, Costa Rica.
| | - Gilbert D Loría
- Sección de Virología, Centro de Investigación en Enfermedades Tropicales (CIET), and Centro de Investigaciones en Hematología y Trastornos Afines (CIHATA), Universidad de Costa Rica, San José, Costa Rica.
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica.
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7
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Kuwata H, Yuzurihara C, Kinoshita N, Taki Y, Ikegami Y, Washio S, Hirakawa Y, Yoda E, Aiuchi T, Itabe H, Nakatani Y, Hara S. The group VIA calcium‐independent phospholipase A
2
and NFATc4 pathway mediates IL‐1β‐induced expression of chemokines CCL2 and CXCL10 in rat fibroblasts. FEBS J 2018; 285:2056-2070. [DOI: 10.1111/febs.14462] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/15/2018] [Accepted: 04/03/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Hiroshi Kuwata
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Chihiro Yuzurihara
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Natsumi Kinoshita
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Yuki Taki
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Yuki Ikegami
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Sana Washio
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Yushi Hirakawa
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Emiko Yoda
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Toshihiro Aiuchi
- Division of Biological Chemistry Department of Molecular Biology School of Pharmacy Showa University Tokyo Japan
| | - Hiroyuki Itabe
- Division of Biological Chemistry Department of Molecular Biology School of Pharmacy Showa University Tokyo Japan
| | - Yoshihito Nakatani
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
| | - Shuntaro Hara
- Division of Health Chemistry Department of Healthcare and Regulatory Sciences School of Pharmacy Showa University Tokyo Japan
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8
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Lin Y, Bogdanov M, Lu S, Guan Z, Margolin W, Weiss J, Zheng L. The phospholipid-repair system LplT/Aas in Gram-negative bacteria protects the bacterial membrane envelope from host phospholipase A 2 attack. J Biol Chem 2018; 293:3386-3398. [PMID: 29348168 PMCID: PMC5836115 DOI: 10.1074/jbc.ra117.001231] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/15/2018] [Indexed: 11/06/2022] Open
Abstract
Secretory phospholipases A2 (sPLA2s) are potent components of mammalian innate-immunity antibacterial mechanisms. sPLA2 enzymes attack bacteria by hydrolyzing bacterial membrane phospholipids, causing membrane disorganization and cell lysis. However, most Gram-negative bacteria are naturally resistant to sPLA2 Here we report a novel resistance mechanism to mammalian sPLA2 in Escherichia coli, mediated by a phospholipid repair system consisting of the lysophospholipid transporter LplT and the acyltransferase Aas in the cytoplasmic membrane. Mutation of the lplT or aas gene abolished bacterial lysophospholipid acylation activity and drastically increased bacterial susceptibility to the combined actions of inflammatory fluid components and sPLA2, resulting in bulk phospholipid degradation and loss of colony-forming ability. sPLA2-mediated hydrolysis of the three major bacterial phospholipids exhibited distinctive kinetics and deacylation of cardiolipin to its monoacyl-derivative closely paralleled bacterial death. Characterization of the membrane envelope in lplT- or aas-knockout mutant bacteria revealed reduced membrane packing and disruption of lipid asymmetry with more phosphatidylethanolamine present in the outer leaflet of the outer membrane. Moreover, modest accumulation of lysophospholipids in these mutant bacteria destabilized the inner membrane and rendered outer membrane-depleted spheroplasts much more sensitive to sPLA2 These findings indicated that LplT/Aas inactivation perturbs both the outer and inner membranes by bypassing bacterial membrane maintenance mechanisms to trigger specific interfacial activation of sPLA2 We conclude that the LplT/Aas system is important for maintaining the integrity of the membrane envelope in Gram-negative bacteria. Our insights may help inform new therapeutic strategies to enhance host sPLA2 antimicrobial activity.
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Affiliation(s)
- Yibin Lin
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
| | | | - Shuo Lu
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
| | - Ziqiang Guan
- the Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, and
| | - William Margolin
- Microbiology and Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas 77030
| | - Jerrold Weiss
- the Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Lei Zheng
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
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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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10
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Endogenous secreted phospholipase A2 group X regulates cysteinyl leukotrienes synthesis by human eosinophils. J Allergy Clin Immunol 2015; 137:268-277.e8. [PMID: 26139511 DOI: 10.1016/j.jaci.2015.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 04/23/2015] [Accepted: 05/04/2015] [Indexed: 02/05/2023]
Abstract
BACKGROUND Phospholipase A2s mediate the rate-limiting step in the formation of eicosanoids such as cysteinyl leukotrienes (CysLTs). Group IVA cytosolic PLA2α (cPLA2α) is thought to be the dominant PLA2 in eosinophils; however, eosinophils also have secreted PLA2 (sPLA2) activity that has not been fully defined. OBJECTIVES To examine the expression of sPLA2 group X (sPLA2-X) in eosinophils, the participation of sPLA2-X in the formation of CysLTs, and the mechanism by which sPLA2-X initiates the synthesis of CysLTs in eosinophils. METHODS Peripheral blood eosinophils were obtained from volunteers with asthma and/or allergy. A rabbit polyclonal anti-sPLA2-X antibody identified sPLA2-X by Western blot. We used confocal microscopy to colocalize the sPLA2-X to intracellular structures. An inhibitor of sPLA2-X (ROC-0929) that does not inhibit other mammalian sPLA2s, as well as inhibitors of the mitogen-activated kinase cascade (MAPK) and cPLA2α, was used to examine the mechanism of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-mediated formation of CysLT. RESULTS Eosinophils express the mammalian sPLA2-X gene (PLA2G10). The sPLA2-X protein is located in the endoplasmic reticulum, golgi, and granules of eosinophils and moves to the granules and lipid bodies during fMLP-mediated activation. Selective sPLA2-X inhibition attenuated the fMLP-mediated release of arachidonic acid and CysLT formation by eosinophils. Inhibitors of p38, extracellular-signal-regulated kinases 1/2 (p44/42 MAPK), c-Jun N-terminal kinase, and cPLA2α also attenuated the fMLP-mediated formation of CysLT. The sPLA2-X inhibitor reduced the phosphorylation of p38 and extracellular-signal-regulated kinases 1/2 (p44/42 MAPK) as well as cPLA2α during cellular activation, indicating that sPLA2-X is involved in activating the MAPK cascade leading to the formation of CysLT via cPLA2α. We further demonstrate that sPLA2-X is activated before secretion from the cell during activation. Short-term priming with IL-13 and TNF/IL-1β increased the expression of PLA2G10 by eosinophils. CONCLUSIONS These results demonstrate that sPLA2-X plays a significant role in the formation of CysLTs by human eosinophils. The predominant role of the enzyme is the regulation of MAPK activation that leads to the phosphorylation of cPLA2α. The sPLA2-X protein is regulated by proteolytic cleavage, suggesting that an inflammatory environment may promote the formation of CysLTs through this mechanism. These results have important implications for the treatment of eosinophilic disorders such as asthma.
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11
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Weiss JP. Molecular determinants of bacterial sensitivity and resistance to mammalian Group IIA phospholipase A2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3072-7. [PMID: 26079797 DOI: 10.1016/j.bbamem.2015.05.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/18/2015] [Accepted: 05/20/2015] [Indexed: 11/25/2022]
Abstract
Group IIA secretory phospholipase A2 (sPLA(2)-IIA) of mammalian species is unique among the many structurally and functionally related mammalian sPLA(2) in their high net positive charge and potent (nM) antibacterial activity. Toward the Gram-positive bacteria tested thus far, the global cationic properties of sPLA(2)-IIA are necessary for optimal binding to intact bacteria and penetration of the multi-layered thick cell wall, but not for the degradation of membrane phospholipids that is essential for bacterial killing. Various Gram-positive bacterial species can differ as much as 1000-fold in sPLA(2)-IIA sensitivity despite similar intrinsic enzymatic activity of sPLA(2)-IIA toward the membrane phospholipids of various bacteria. d-alanylation of wall- and lipo-teichoic acids in Staphylococcus aureus and sortase function in Streptococcus pyogenes increase bacterial resistance to sPLA(2)-IIA by up to 100-fold apparently by affecting translocation of bound sPLA(2)-IIA to the cell membrane. Action of the sPLA(2)-IIA and other related sPLA(2) against Gram-negative bacteria is more dependent on cationic properties of the enzyme near the amino-terminus of the protein and collaboration with other host defense proteins that produce alterations of the unique Gram-negative bacterial outer membrane that normally represents a barrier to sPLA(2)-IIA action. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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Affiliation(s)
- Jerrold P Weiss
- The Inflammation Program, University of Iowa, Iowa City, IA 52242, USA; Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA; Veterans Administration Medical Center, Iowa City, IA 52246, USA.
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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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The enteric nervous system neuropeptide, bombesin, reverses innate immune impairments during parenteral nutrition. Ann Surg 2015; 260:432-43; discussion 443-4. [PMID: 25115419 DOI: 10.1097/sla.0000000000000871] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Lack of enteral stimulation during parenteral nutrition (PN) impairs mucosal immunity. Bombesin (BBS), a gastrin-releasing peptide analogue, reverses PN-induced defects in acquired immunity. Paneth cells produce antimicrobial peptides (AMPs) of innate immunity for release after cholinergic stimulation. OBJECTIVE Determine if BBS restores AMPs and bactericidal function during PN. METHODS Intravenously cannulated male ICR mice were randomized to Chow, PN, or PN+BBS (15 μg 3 times daily, n = 7 per group) for 5 days. Ileum was analyzed for AMPs (Protein: sPLA2 by fluorescence, lysozyme and RegIII-γ by western andcryptdin-4 by ELISA; mRNA: all by RT-PCR). Cholinergic stimulated (100 μM bethanechol) ileal specimens assessed Pseudomonas bactericidal activity. Ileum (Chow: n = 7; PN: n = 9; PN+BBS: n = 8) was assessed for Escherichia coli invasion in ex-vivo culture. RESULTS PN significantly decreased most AMPs versus Chow while BBS maintained Chow levels (sPLA2: Chow: 107 + 14*, PN: 44.6 + 7.2, PN+BBS: 78.7 + 13.4* Fl/min/μL/total protein; Lysozyme: Chow: 63.9 + 11.9*, PN: 26.8 + 6.2; PN+BBS: 64.9 + 13.8* lysozyme/total protein; RegIII-γ: Chow: 51.5 + 10.0*, PN: 20.4 + 4.3, PN+BBS: 31.0 + 8.4 RegIII-γ/total protein; Cryptdin-4: Chow: 18.4 + 1.5*, PN: 12.7 + 1.6, PN+BBS: 26.1 + 2.4*† pg/mg [all *P < 0.05 vs PN and †P < 0.05 vs Chow]). Functionally, BBS prevented PN loss of bactericidal activity after cholinergic stimulation (Chow: 25.3 + 3.6*, PN: 13.0 + 3.2; PN+BBS: 27.0 + 4.7* percent bacterial killing, *P < 0.05 vs PN). BBS reduced bacterial invasion in unstimulated tissue barely missing significance (P = 0.06). CONCLUSIONS The enteric nervous system (ENS) controls AMP levels in Paneth cells during PN but mucosal protection by innate immunity requires both ENS and parasympathetic stimulation.
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Bacha AB. Anti-bactericidal properties of stingray Dasyatis pastinaca groups V, IIA, and IB phospholipases A2: a comparative study. Appl Biochem Biotechnol 2014; 174:1520-1534. [PMID: 25119545 DOI: 10.1007/s12010-014-1069-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/21/2014] [Indexed: 11/25/2022]
Abstract
Group IIA secreted phospholipase A2 (group IIA sPLA2) is known to display potent Gram-positive bactericidal activity in vitro and in vivo. We have analyzed the bactericidal activity of the full set of native stingray and dromedary groups V, IIA, and IB sPLA2s on several Gram-positive and Gram-negative strains. The rank order potency among both marine and mammal sPLA2s against Gram-positive bacteria is group IIA > V > IB, whereas Gram-negative bacteria exhibited a much higher resistance. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2.The bactericidal efficiency of groups V and IIA sPLA2s was shown to be dependent upon the presence of calcium ions and to a less extent Mg(2+) ions and then a correlation could be made to its hydrolytic activity of membrane phospholipids. Importantly, we showed that stingray and dromedary groups V, IIA, and IB sPLA2s present no cytotoxicity after their incubation with MDA-MB-231cells. stingray groups V and IIA sPLA2s, like mammal ones, may be considered as future therapeutic agents against bacterial infections.
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Affiliation(s)
- Abir Ben Bacha
- Biochemistry Department, Science College, King Saud University, P.O Box 22452, Riyadh, 11495, Saudi Arabia. .,Laboratory of Plant Biotechnology Applied to Crop Improvement, Faculty of Science of Sfax, University of Sfax, Sfax, 3038, Tunisia.
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15
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Abstract
BACKGROUND Parenteral nutrition (PN) increases risks of infections in critically injured patients. Recently, PN was shown to reduce intestine luminal levels of the Paneth cell antimicrobial molecule secretory phospholipase A2 (sPLA2) and the goblet cell glycoprotein mucin2 (MUC2). These molecules are critical factors for innate mucosal immunity and provide barrier protection. Interleukin-4 (IL-4) and IL-13 regulate sPLA2 and MUC2 production through the IL-13 receptor. Because IL-25 stimulates IL-4 and IL-13 release and PN reduces luminal sPLA2 and MUC2, we hypothesized that adding IL-25 to PN would restore these innate immune factors and maintain barrier function. METHODS Two days after venous cannulation, male ICR (Institute of Cancer Research) mice were randomized to receive chow (n = 12), PN (n = 9), or PN + 0.7 μg of exogenous IL-25 (n = 11) daily for 5 days. Small-intestine wash fluid (SIWF) was collected for analysis of sPLA2 activity, MUC2 density, and luminal levels of IL-4 and IL-13. Small-intestinal tissue was harvested for analysis of tissue sPLA2 activity or immediate use in an ex-vivo intestinal segment culture (EVISC) to assess susceptibility of the tissue segments to enteroinvasive Escherichia coli. RESULTS PN reduced luminal sPLA2 (P < 0.0001) and MUC2 (P <0.002) compared with chow, whereas the addition of IL-25 to PN increased luminal sPLA2 (P < 0.0001) and MUC2 (P < 0.02) compared with PN. Tissue IL-4 and IL-13 decreased with PN compared with chow (IL-4: P < 0.0001, IL-13: P < 0.002), whereas IL-25 increased both cytokines compared with PN (IL-4: P < 0.03, IL-13: P < 0.02). Tissue levels of sPLA2 were significantly decreased with PN compared with chow, whereas IL-25 significantly increased tissue sPLA2 levels compared with PN alone. Functionally, more bacteria invaded the PN-treated tissue compared with chow (P < 0.01), and the addition of IL-25 to PN decreased enteroinvasion to chow levels (P < 0.01). CONCLUSIONS PN impairs innate mucosal immunity by suppressing luminal sPLA2 activity and MUC2 density compared with chow. PN also increases bacterial invasion in ex-vivo tissue. Administration of exogenous IL-25 reverses this dysfunction and increases luminal sPLA2 and MUC2. PN tissue treated with IL-25 was significantly more resistant to bacterial invasion than with PN alone, suggesting that IL-25-induced effects augment the barrier defense mechanisms.
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Antibacterial properties of recombinant human non-pancreatic secretory phospholipase A2. Biochem Biophys Res Commun 2013; 441:453-6. [DOI: 10.1016/j.bbrc.2013.10.092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 10/17/2013] [Indexed: 11/23/2022]
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Heneghan AF, Pierre JF, Tandee K, Shanmuganayagam D, Wang X, Reed JD, Steele JL, Kudsk KA. Parenteral nutrition decreases paneth cell function and intestinal bactericidal activity while increasing susceptibility to bacterial enteroinvasion. JPEN J Parenter Enteral Nutr 2013; 38:817-824. [PMID: 23894173 DOI: 10.1177/0148607113497514] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Parenteral nutrition (PN) increases the risk of infection in patients with contraindication to enteral feeding. Paneth cells produce and secrete antimicrobial products that protect the mucosa from pathogens. Their loss is associated with increased host-pathogen interactions, mucosal inflammation, and altered microbiome composition. HYPOTHESIS We hypothesized that PN reduces Paneth cell product expression, and these changes would reduce bactericidal properties of tissue secretions following cholinergic stimulation, increase mucosal enteroinvasion, and shift the intestinal microbiome. METHOD Experiment 1: Male ICR mice were randomized to Chow (n = 8) or PN (n = 8). Ileum tissue was collected for Paneth cell antimicrobial expression using RT-PCR, stimulated with a cholinergic agonist degranulate Paneth cells bactericidal activity, or used to assess bacterial enteroinvasion in EVISC. Experiment 2: Mice were randomized to Chow (n = 11) or PN (n = 8) and ileum washing was collected for 16s pyrosequencing analysis. RESULTS Compared to Chow, PN decreased tissue expression of REGIII-g (p < 0.002), lysozyme (p < 0.002), and cryptdin-4 (p < 0.03). At the phylum level, PN decreased total Firmicutes but increased total Bacteroidetes, and Proteobacteria. Functionally, secretions from PN tissue was less bactericidal (p < 0.03) and demonstrated increased susceptibility to enteroinvasion by E coli (p < 0.02). CONCLUSION PN without enteral nutrition impairs innate mucosal immune function. Tissue expression of Paneth cell antimicrobial proteins decreases associated with compositional shifts to the microbiome, decreased bactericidal activity of mucosal secretions and greater susceptibility of to enteroinvasion by E coli. These changes may explain in-part the increased risk of infection in parenterally fed patients.
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Affiliation(s)
- Aaron F Heneghan
- Surgical Service of the William S. Middleton Veteran Memorial Hospital, Madison WI, USA.,Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Joseph F Pierre
- Surgical Service of the William S. Middleton Veteran Memorial Hospital, Madison WI, USA.,Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Kanokwan Tandee
- Department of Food Science, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Xinying Wang
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA.,Department of Surgery, Nanjing University, Jinling hospital, Nanjing, China
| | - Jess D Reed
- Reed Research Group, Department of Animal Sciences, University of Wisconsin -Madison, Madison, WI 53706
| | - James L Steele
- Department of Food Science, University of Wisconsin-Madison, Madison, WI, USA
| | - Kenneth A Kudsk
- Surgical Service of the William S. Middleton Veteran Memorial Hospital, Madison WI, USA.,Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
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Ben Bacha A, Abid I, Horchani H. Antibacterial properties of intestinal phospholipase A2 from the common stingray Dasyatis pastinaca. Appl Biochem Biotechnol 2012; 168:1277-87. [PMID: 22956299 DOI: 10.1007/s12010-012-9856-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/21/2012] [Indexed: 11/29/2022]
Abstract
Stingray phospholipase A(2) group IIA (SPLA(2)-IIA) was recently isolated and purified to homogeneity from the intestine of the common stingray Dasyatis pastinaca, suggesting that this enzyme plays an important role in systemic bactericidal defense. The present study showed that SPLA(2)-IIA was highly bactericidal against Gram-positive bacteria with inhibition zones and minimal inhibitory concentration values in the range of 13-25 mm and 2-8 μg/ml, respectively, whereas Gram-negative bacteria exhibited a much higher resistance. The bactericidal efficiency of SPLA(2)-IIA was shown to be unaffected by high protein and salt concentrations, but dependent upon the presence of calcium ions, and then correlated to the hydrolytic activity of membrane phospholipids. Importantly, we showed that stingray phospholipase A(2) group IIA presents no cytotoxicity after its incubation with MDA-MB-231 cells. SPLA(2)-IIA may be considered as a future therapeutic agent against bacterial infections.
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Affiliation(s)
- Abir Ben Bacha
- Biochemistry Department, Science College, King Saud University, Riyadh, Saudi Arabia.
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Uusitalo-Seppälä R, Peuravuori H, Koskinen P, Vahlberg T, Rintala EM. Role of plasma bactericidal/permeability-increasing protein, group IIA phospholipase A2, C-reactive protein, and white blood cell count in the early detection of severe sepsis in the emergency department. ACTA ACUST UNITED AC 2012; 44:697-704. [DOI: 10.3109/00365548.2012.677061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Pierre JF, Heneghan AF, Tsao FHC, Sano Y, Jonker MA, Omata J, Lan J, Kudsk KA. Route and type of nutrition and surgical stress influence secretory phospholipase A2 secretion of the murine small intestine. JPEN J Parenter Enteral Nutr 2012; 35:748-56. [PMID: 22042050 DOI: 10.1177/0148607111414025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The function of secretory phospholipase A2 (sPLA2) is site dependent. In tissue, sPLA2 regulates eicosanoid production; in circulation, sPLA2 primes neutrophils; and in the intestinal lumen, sPLA2 provides innate bactericidal immunity as a defensin-related protein. Since parenteral nutrition (PN) primes leukocytes while suppressing intraluminal mucosal immunity, the authors hypothesized that (1) PN would diminish luminal sPLA2 activity but increase activity in intestinal tissue and serum and (2) stress would accentuate these changes. METHODS Mice received chow, a complex enteral diet (CED), intragastric PN (IG-PN), or PN in experiment 1 and chow, chow+stress, PN, or PN+stress in experiment 2. RESULTS In experiment 1, luminal sPLA2 activity was greatest in chow and decreased in CED, IG-PN, and PN, with PN lower than CED and IG-PN. Compared to that after chow, serum sPLA2 activity dropped after CED, IG-PN, and PN. Serum sPLA2 was higher in portal than systemic serum. In experiment 2, PN lowered luminal sPLA2 activity vs chow. Stress lowered luminal sPLA2 activity in chow, without change in PN. Following stress, luminal immunoglobulin A increased in chow but not PN. Serum sPLA2 activity increased in PN. CONCLUSIONS PN attenuates sPLA2 activity in intestinal fluid, consistent with suppressed innate mucosal defense. Stress suppresses luminal fluid sPLA2 activity in chow but not the immunoglobulin A response; PN impairs both. Stress significantly elevates serum sPLA2 in PN-fed mice, consistent with known increased neutrophil priming with PN. PN reduces innate bactericidal immunity of the gut but upregulates serum proinflammatory products poststress.
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Affiliation(s)
- Joseph F Pierre
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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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: 820] [Impact Index Per Article: 63.1] [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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Abstract
The human intestine contains huge amounts of nonpathologic bacteria surviving in an environment that is beneficial to both the host and the bacterial populations. When short pauses in oral intake occur with minimal alterations in the mucosa-microbial interface, critical illness, with its attendant acidosis, prolonged gastrointestinal tract starvation, exogenous antibiotics, and breakdown in mucosal defenses, renders the host vulnerable to bacterial challenge and also threatens the survival of the bacteria. This review examines the altered innate and adaptive immunologic host defenses that occur as a result of altered oral or enteral intake and/or injury.
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Affiliation(s)
- Kazuhiko Fukatsu
- Department of Surgery, Surgical Center, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 1138655, Japan
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Koprivnjak T, Peschel A. Bacterial resistance mechanisms against host defense peptides. Cell Mol Life Sci 2011; 68:2243-54. [PMID: 21560069 PMCID: PMC11115334 DOI: 10.1007/s00018-011-0716-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 04/26/2011] [Accepted: 04/26/2011] [Indexed: 12/30/2022]
Abstract
Host defense peptides and proteins are important components of the innate host defense against pathogenic microorganisms. They target negatively charged bacterial surfaces and disrupt microbial cytoplasmic membranes, which ultimately leads to bacterial destruction. Throughout evolution, pathogens devised several mechanisms to protect themselves from deleterious damage of host defense peptides. These strategies include (a) inactivation and cleavage of host defense peptides by production of host defense binding proteins and proteases, (b) repulsion of the peptides by alteration of pathogen's surface charge employing modifications by amino acids or amino sugars of anionic molecules (e.g., teichoic acids, lipid A and phospholipids), (c) alteration of bacterial membrane fluidity, and (d) expulsion of the peptides using multi drug pumps. Together with bacterial regulatory network(s) that regulate expression and activity of these mechanisms, they represent attractive targets for development of novel antibacterials.
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Affiliation(s)
- Tomaz Koprivnjak
- Department of Biotechnology, National Institute of Chemistry Slovenia, Hajdrihova 19, 1000, Ljubljana, Slovenia,
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Characterization of Staphylococcus aureus cardiolipin synthases 1 and 2 and their contribution to accumulation of cardiolipin in stationary phase and within phagocytes. J Bacteriol 2011; 193:4134-42. [PMID: 21665977 DOI: 10.1128/jb.00288-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In many bacteria, including Staphylococcus aureus, progression from the logarithmic to the stationary phase is accompanied by conversion of most of bacterial membrane phosphatidylglycerol (PG) to cardiolipin (CL). Phagocytosis of S. aureus by human neutrophils also induces the conversion of most bacterial PG to CL. The genome of all sequenced strains of S. aureus contains two open reading frames (ORFs) predicting proteins encoded with ∼30% identity to the principal CL synthase (cls) of Escherichia coli. To test whether these ORFs (cls1 and cls2) encode cardiolipin synthases and contribute to CL accumulation in S. aureus, we expressed these proteins in a cls strain of E. coli and created isogenic single and double mutants in S. aureus. The expression of either Cls1 or Cls2 in CL-deficient E. coli resulted in CL accumulation in the stationary phase. S. aureus with deletion of both cls1 and cls2 showed no detectable CL accumulation in the stationary phase or after phagocytosis by neutrophils. CL accumulation in the stationary phase was due almost solely to Cls2, whereas both Cls1 and Cls2 contributed to CL accumulation following phagocytosis by neutrophils. Differences in the relative contributions of Cls1 and Cls2 to CL accumulation under different triggering conditions suggest differences in the role and regulation of these two enzymes.
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Karray A, Ali YB, Gargouri Y, Bezzine S. Antibacterial properties of chicken intestinal phospholipase A2. Lipids Health Dis 2011; 10:4. [PMID: 21226897 PMCID: PMC3024238 DOI: 10.1186/1476-511x-10-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 01/12/2011] [Indexed: 11/23/2022] Open
Abstract
Background The presence of chicken group-IIA PLA2 (ChPLA2-IIA) in the intestinal secretion suggests that this enzyme plays an important role in systemic bactericidal defence. We have analyzed the bactericidal activity of purified ChPLA2-IIA, on several gram-positive and gram-negative bacteria by using the diffusion well and dilution methods. Results ChPLA2-IIA displays potent bactericidal activity against gram-positive bacteria but lacks bactericidal activity against gram negative ones. We have also demonstrated a synergic action of ChPLA2-IIA with lysozyme when added to the bacteria culture prior to ChPLA2-IIA. The bactericidal efficiency of ChPLA2-IIA was shown to be dependent upon the presence of calcium ions and then a correlation could be made to its hydrolytic activity of membrane phospholipids. Interestingly ChPLA2-IIA displays a higher dependence to Ca2+ ions than to Mg2+ions. Conclusion We conclude that the main physiological role of ChPLA2-IIA could be the defence of the intestine against bacterial invasions.
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Affiliation(s)
- Aida Karray
- Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS Route de Soukra, 3038 Sfax, University of Sfax, Tunisia
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Hatzidaki E, Nakos G, Galiatsou E, Lekka ME. Impaired phospholipases A₂production by stimulated macrophages from patients with acute respiratory distress syndrome. Biochim Biophys Acta Mol Basis Dis 2010; 1802:986-94. [PMID: 20600872 DOI: 10.1016/j.bbadis.2010.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 06/09/2010] [Accepted: 06/11/2010] [Indexed: 01/31/2023]
Abstract
The aim of this study was to investigate whether early phase of acute respiratory distress syndrome (ARDS) is associated with changes in immune response, either systemic or localized to the lung. ARDS and control mechanically ventilated patients, as well as healthy volunteers were studied. Alveolar macrophages (AMΦ) and blood monocytes (BM) were treated ex vivo with lipopolysaccharide (LPS), interferon-γ (IFNγ), and surfactant. Phospholipase A₂ (PLA₂) activity and TLR4 expression were evaluated as markers of cell response. AMΦ from ARDS patients did not respond upon treatment with either LPS or IFN-γ by inducing PLA₂ production. On the contrary, upon stimulation, in control patients the intracellular PLA₂, (mainly cPLA₂) levels were increased, but secretion of PLA₂ (mainly sPLA₂-IIA) was observed only after treatment with LPS. Surfactant suppressed PLA₂ production in cells from both groups of patients. Increased relative changes of total PLA₂ activity and an upregulation of TLR4 expression upon stimulation was observed in BM from primary ARDS, control patients and healthy volunteers. In BM from secondary ARDS patients, however, no PLA₂ induction was observed, with a concomitant down-regulation of TLR4 expression. Cytosolic PLA₂, its activated form, p-cPLA₂, and sPLA₂-IIA were the predominant PLA₂ types within the cells, while extracellularly only sPLA₂-IIA was identified. These results support the concept of down-regulated innate immunity in early ARDS that is compartmentalized in primary and systemic in secondary ARDS. PLA₂ isoforms could serve as markers of the immunity status in ARDS. Finally, our data highlight the role of surfactant in controlling inflammation.
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Affiliation(s)
- Eleana Hatzidaki
- Chemistry Department, University of Ioannina, 45100 Ioannina, Greece
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Catalytic and non-catalytic functions of human IIA phospholipase A2. Trends Biochem Sci 2009; 35:28-35. [PMID: 19818633 DOI: 10.1016/j.tibs.2009.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 07/31/2009] [Accepted: 08/04/2009] [Indexed: 11/30/2022]
Abstract
Group IIA phospholipase A2 (PLA2) is a low-molecular-mass secreted PLA2 enzyme that has been identified as an acute phase protein with a role in the inflammatory response to infection and trauma. The protein is possibly unique in being highly cationic and having a global distribution of surface arginine and lysine residues. This structure supports two functions of the protein. (1) An anti-bacterial role where the enzyme is targeted to the anionic cell membrane of Gram-positive bacteria and phospholipid hydrolysis assists in bacterial killing. (2) A proposed non-catalytic role in which the protein forms supramolecular aggregates with anionic phospholipid vesicles or debris. These aggregates are then internalized via interactions with cell surface heparin sulphate proteoglycans and macropinocytosis for disposal by macrophages.
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Raymond B, Leduc D, Ravaux L, Le Goffic R, Candela T, Raymondjean M, Goossens PL, Touqui L. Edema toxin impairs anthracidal phospholipase A2 expression by alveolar macrophages. PLoS Pathog 2008; 3:e187. [PMID: 18069891 PMCID: PMC2134952 DOI: 10.1371/journal.ppat.0030187] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 10/26/2007] [Indexed: 01/14/2023] Open
Abstract
Bacillus anthracis, the etiological agent of anthrax, is a spore-forming Gram-positive bacterium. Infection with this pathogen results in multisystem dysfunction and death. The pathogenicity of B. anthracis is due to the production of virulence factors, including edema toxin (ET). Recently, we established the protective role of type-IIA secreted phospholipase A2 (sPLA2-IIA) against B. anthracis. A component of innate immunity produced by alveolar macrophages (AMs), sPLA2-IIA is found in human and animal bronchoalveolar lavages at sufficient levels to kill B. anthracis. However, pulmonary anthrax is almost always fatal, suggesting the potential impairment of sPLA2-IIA synthesis and/or action by B. anthracis factors. We investigated the effect of purified ET and ET-deficient B. anthracis strains on sPLA2-IIA expression in primary guinea pig AMs. We report that ET inhibits sPLA2-IIA expression in AMs at the transcriptional level via a cAMP/protein kinase A–dependent process. Moreover, we show that live B. anthracis strains expressing functional ET inhibit sPLA2-IIA expression, whereas ET-deficient strains induced this expression. This stimulatory effect, mediated partly by the cell wall peptidoglycan, can be counterbalanced by ET. We conclude that B. anthracis down-regulates sPLA2-IIA expression in AMs through a process involving ET. Our study, therefore, describes a new molecular mechanism implemented by B. anthracis to escape innate host defense. These pioneering data will provide new molecular targets for future intervention against this deathly pathogen. All mammals are susceptible to infection by Bacillus anthracis, the etiological agent of anthrax. Infection can occur either accidentally or as a potential consequence of a terrorism threat. Pulmonary infection is the most life-threatening form of the disease, causing a near 100% mortality. Despite appropriate therapy, all forms of infection may progress to fatal systemic anthrax, characterized by sepsis and respiratory failure. Thus, it is important to understand the mechanisms of host defense against B. anthracis. We have previously shown that alveolar macrophages produce an enzyme involved in innate defense that can kill B. anthracis: the enzyme is known as secreted phospholipase A2-IIA (sPLA2-IIA). The alveolar macrophage is one of the first cell types to come in contact with B. anthracis. In this study, we show that live B. anthracis spores stimulate the synthesis of sPLA2-IIA, this stimulation being counterbalanced by the inhibitory effect of the edema toxin produced by germinated spores and bacilli. Our study suggests that inhibition of sPLA2-IIA synthesis by edema toxin is a mechanism by which B. anthracis can escape innate host defense. These pioneering data provide new molecular targets for future intervention against this deadly pathogen.
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Affiliation(s)
- Benoit Raymond
- Institut Pasteur, Unité de Défense Innée et Inflammation, Paris, France
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Wall teichoic acid deficiency in Staphylococcus aureus confers selective resistance to mammalian group IIA phospholipase A(2) and human beta-defensin 3. Infect Immun 2008; 76:2169-76. [PMID: 18347049 DOI: 10.1128/iai.01705-07] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wall teichoic acids (WTAs) and membrane lipoteichoic acids (LTAs) are the major polyanionic polymers in the envelope of Staphylococcus aureus. WTAs in S. aureus play an important role in bacteriophage attachment and bacterial adherence to certain host cells, suggesting that WTAs are exposed on the cell surface and could also provide necessary binding sites for cationic antimicrobial peptides and proteins (CAMPs). Highly cationic mammalian group IIA phospholipase A(2) (gIIA PLA(2)) kills S. aureus at nanomolar concentrations by an action(s) that depends on initial electrostatic interactions, cell wall penetration, membrane phospholipid (PL) degradation, and activation of autolysins. A tagO mutant of S. aureus that lacks WTA is up to 100-fold more resistant to PL degradation and killing by gIIA PLA(2) and CAMP human beta-defensin 3 (HBD-3) but has the sensitivity of the wild type (wt) to other CAMPs, such as Magainin II amide, hNP1-3, LL-37, and lactoferrin. In contrast, there is little or no difference in either gIIA PLA(2) activity toward cell wall-depleted protoplasts of the wt and tagO strains of S. aureus or in binding of gIIA PLA(2) to wt and tagO strains. Scanning and transmission electron microscopy reveal increased surface protrusions in the S. aureus tagO mutant that might account for reduced activity of bound gIIA PLA(2) and HBD-3 toward the tagO mutant. In summary, the absence of WTA in S. aureus causes a selective increase in bacterial resistance to gIIA PLA(2) and HBD-3, the former apparently by reducing access and/or activity of bound antibacterial enzyme to the bacterial membrane.
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Kuwata H, Fujimoto C, Yoda E, Shimbara S, Nakatani Y, Hara S, Murakami M, Kudo I. A novel role of group VIB calcium-independent phospholipase A2 (iPLA2gamma) in the inducible expression of group IIA secretory PLA2 in rat fibroblastic cells. J Biol Chem 2007; 282:20124-32. [PMID: 17475622 DOI: 10.1074/jbc.m611883200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Group IIA secretory phospholipase A(2) (sPLA(2)-IIA) is a prototypic sPLA(2) enzyme that may play roles in modification of eicosanoid biosynthesis as well as antibacterial defense. In several cell types, inducible expression of sPLA(2) by pro-inflammatory stimuli is attenuated by group IVA cytosolic PLA(2) (cPLA(2)alpha) inhibitors such as arachidonyl trifluoromethyl ketone, leading to the proposal that prior activation of cPLA(2)alpha is required for de novo induction of sPLA(2). However, because of the broad specificity of several cPLA(2)alpha inhibitors used so far, a more comprehensive approach is needed to evaluate the relevance of this ambiguous pathway. Here, we provide evidence that the induction of sPLA(2)-IIA by pro-inflammatory stimuli requires group VIB calcium-independent PLA(2) (iPLA(2)gamma), rather than cPLA(2)alpha, in rat fibroblastic 3Y1 cells. Results with small interfering RNA unexpectedly showed that the cytokine induction of sPLA(2)-IIA in cPLA(2)alpha knockdown cells, in which cPLA(2)alpha protein was undetectable, was similar to that in replicate control cells. By contrast, knockdown of iPLA(2)gamma, another arachidonyl trifluoromethyl ketone-sensitive intracellular PLA(2), markedly reduced the cytokine-induced expression of sPLA(2)-IIA. Supporting this finding, the R-enantiomer of bromoenol lactone, an iPLA(2)gamma inhibitor, suppressed the cytokine-induced sPLA(2)-IIA expression, whereas (S)-bromoenol lactone, an iPLA(2)beta inhibitor, failed to do so. Moreover, lipopolysaccharide-stimulated sPLA(2)-IIA expression was also abolished by knockdown of iPLA(2)gamma. These findings open new insight into a novel regulatory role of iPLA(2)gamma in stimulus-coupled sPLA(2)-IIA expression.
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Affiliation(s)
- Hiroshi Kuwata
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555
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31
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Solodkin-Szaingurten I, Levy R, Hadad N. Differential behavior of sPLA2-V and sPLA2-X in human neutrophils. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:155-63. [PMID: 17275398 DOI: 10.1016/j.bbalip.2006.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 11/30/2006] [Accepted: 11/30/2006] [Indexed: 11/29/2022]
Abstract
Neutrophils and differentiated PLB-985 cells contain various types of PLA(2)s including the 85 kDa cytosolic PLA(2) (cPLA(2)), Ca(2+)-independent PLA(2) (iPLA(2)) and secreted PLA(2)s (sPLA(2)s). The present study focuses on the behavior of sPLA(2)s in neutrophils and PLB cells and their relationship to cPLA(2)alpha. The results of the present research show that the two types of sPLA(2) present in neutrophils, sPLA(2)-V and sPLA(2)-X, which are located in the azurophil granules, are differentially affected by physiological stimuli. While sPLA(2)-V is secreted to the extacellular milieu, sPLA(2)-X is detected on the plasma membranes after stimulation. Stimulation of neutrophils with formyl-Met-Leu-Phe (fMLP), opsonized zymosan (OZ) or A23187 resulted in a different kinetics of sPLA(2) secretion as detected by its activity in the neutrophil supernatants. Neutrophil priming by inflammatory cytokines or LPS enhanced sPLA(2) activity detected in the supernatant after stimulation by fMLP. This increased activity was due to increased secretion of sPLA(2)-V to the supernatant and not to release of sPLA(2)-X. sPLA(2) in granulocyte-like PLB cells exhibit identical characteristics to neutrophil sPLA(2), with similar activity and optimal pH of 7.5. Granulocyte-like cPLA(2)alpha-deficient PLB cells serve as a good model to study whether sPLA(2) activity is regulated by cPLA(2)alpha. Secretion and activity of sPLA(2) were found to be similar in granulocyte-like PLB cells expressing or lacking cPLA(2)alpha, indicating that they are not under cPLA(2)alpha regulation.
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Affiliation(s)
- I Solodkin-Szaingurten
- Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, Beer Sheva 84105, Israel
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Levy R. The role of cytosolic phospholipase A2-alfa in regulation of phagocytic functions. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1323-34. [PMID: 17046321 DOI: 10.1016/j.bbalip.2006.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 08/14/2006] [Accepted: 09/06/2006] [Indexed: 11/16/2022]
Abstract
Phospholipase A2(s) (PLA2(s)) are a family of enzymes that is present in a variety of mammalian and nonmammalian sources. Phagocytic cells contain cytosolic PLA2 (cPLA2) as well as several types of secreted PLA2, all of which have the potential to produce proinflammatory lipid mediators. The role of the predominant form of cPLA2 present in neutrophils is cPLA2alpha was studied by many groups. By modulating its expression in a variety of phagocytes it was found that it plays a major role in formation of eicosanoids. In addition, it was reported that cPLA2alpha also regulates the NADPH oxidase activation. The specificity of its effect on the NADPH oxidase is evident by results demonstrating that the differentiation process as well as other phagocytic functions are normal in cPLA2alpha-deficient PLB cell model. The novel dual subcellular localization of cPLA2alpha in different compartments, in the plasma membranes and in the nucleus, provides a molecular mechanism for the participation of cPLA2alpha in different processes (stimulation of NADPH oxidase and formation of eicosanoids) in the same cells.
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Affiliation(s)
- Rachel Levy
- Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, Beer Sheva 84105, Israel.
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Menschikowski M, Hagelgans A, Siegert G. Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases? Prostaglandins Other Lipid Mediat 2006; 79:1-33. [PMID: 16516807 DOI: 10.1016/j.prostaglandins.2005.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/29/2005] [Accepted: 10/31/2005] [Indexed: 02/07/2023]
Abstract
Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie and Laboratoriumsmedizin, Fetscherstrasse 74, D-01307 Dresden, Germany.
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Huhtinen HT, Grönroos JO, Grönroos JM, Uksila J, Gelb MH, Nevalainen TJ, Laine VJO. Antibacterial effects of human group IIA and group XIIA phospholipase A2 against Helicobacter pylori in vitro. APMIS 2006; 114:127-30. [PMID: 16519749 DOI: 10.1111/j.1600-0463.2006.apm_330.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Group IIA phospholipase A2 (PLA2-IIA) is an enzyme which has important roles in inflammation and infection. Recently, a novel human secretory PLA2 called group XIIA PLA2 (PLA2-XIIA) has been identified. Both PLA2-IIA and PLA2-XIIA are bactericidal against Gram-positive bacteria like many other secretory PLA2s. However, PLA2-XIIA is the only known PLA2 displaying significant bactericidal activity against the Gram-negative bacterium Escherichia coli. We examined the antibacterial properties of recombinant human PLA2-IIA and PLA2-XIIA against Helicobacter pylori, a Gram-negative bacterium, in vitro. PLA2-IIA was not bactericidal against H. pylori, whereas PLA2-XIIA effectively killed H. pylori at a concentration of 50 microg/ml but was not bactericidal at concentrations of 0.5 microg/ml and 5 microg/ml.
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Femling JK, Nauseef WM, Weiss JP. Synergy between extracellular group IIA phospholipase A2 and phagocyte NADPH oxidase in digestion of phospholipids of Staphylococcus aureus ingested by human neutrophils. THE JOURNAL OF IMMUNOLOGY 2005; 175:4653-61. [PMID: 16177112 DOI: 10.4049/jimmunol.175.7.4653] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acute inflammatory responses to invading bacteria such as Staphylococcus aureus include mobilization of polymorphonuclear leukocytes (PMN) and extracellular group IIA phospholipase A2 (gIIA-PLA2). Although accumulating coincidentally, the in vitro anti-staphylococcal activities of PMN and gIIA-PLA2 have thus far been studied separately. We now show that degradation of S. aureus phospholipids during and after phagocytosis by human PMN requires the presence of extracellular gIIA-PLA2. The concentration of extracellular gIIA-PLA2 required to produce bacterial digestion was reduced 10-fold by PMN. The effects of added gIIA-PLA2 were greater when present before phagocytosis but even apparent when added after S. aureus were ingested by PMN. Related group V and X PLA2, which are present within PMN granules, do not contribute to bacterial phospholipid degradation during and after phagocytosis even when added at concentrations 30-fold higher than that needed for action of the gIIA-PLA2. The action of added gIIA-PLA2 required catalytically active gIIA-PLA2 and, in PMN, a functional NADPH oxidase but not myeloperoxidase. These findings reveal a novel collaboration between cellular oxygen-dependent and extracellular oxygen-independent host defense systems that may be important in the ultimate resolution of S. aureus infections.
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Affiliation(s)
- Jon K Femling
- The Inflammation Program, University of Iowa and Veterans Affairs Medical Center, Iowa City 52242, USA
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Grönroos JO, Salonen JH, Viander M, Nevalainen TJ, Laine VJO. Roles of Group IIA Phospholipase A2 and Complement in Killing of Bacteria by Acute Phase Serum. Scand J Immunol 2005; 62:413-9. [PMID: 16253130 DOI: 10.1111/j.1365-3083.2005.01678.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The complement system is regarded as an important component of the innate defence system against invading bacteria. However, synergistic actions between the complement and the other components of innate immunity are incompletely known. Human group IIA phospholipase A(2) (hGIIA PLA(2)) is an effective antibacterial enzyme in serum of patients with severe bacterial infections. Our aim was to investigate the significance of complement and hGIIA PLA(2) in acute phase serum. Serum samples were collected from patients with acute bacterial infections and from healthy control subjects. We prepared hGIIA PLA(2)-depleted serum by immunoadsorption and inhibited the activity of complement by a specific inhibitor, compstatin. The bactericidal effects of treated and untreated serum were compared by incubating Staphylococcus aureus and Listeria monocytogenes in the presence of serum. Acute phase serum effectively killed S. aureus and L. monocytogenes, and depletion of hGIIA PLA(2) significantly reduced the antibacterial effect. Complement had a weak bactericidal effect against L. monocytogenes. We conclude that hGIIA PLA(2) is the major antibacterial factor in human acute phase serum against the gram-positive bacteria S. aureus and L. monocytogenes, exceeding complement in efficiency.
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Affiliation(s)
- J O Grönroos
- Department of Pathology, University of Turku, Finland.
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37
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Huhtinen HT, Grönroos JM, Uksila J, Grass DS, Nevalainen TJ, Laine VJO. Experimental Helicobacter felis infection in transgenic mice expressing human group IIA phospholipase A2. Helicobacter 2004; 9:408-16. [PMID: 15361079 DOI: 10.1111/j.1083-4389.2004.00257.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Both various virulence factors of Helicobacter pylori and host factors influence the clinical outcome of H. pylori infection. In animal experiments with Helicobacter felis, large variations in the severity of disease have been observed between different mouse strains infected with a single isolate of H. felis. C57BL/6 J mouse strain that lacks the expression of group IIA phospholipase A2 has been shown to develop more severe gastric inflammation than other mouse strains. Thus, group IIA phospholipase A2 has been suggested to play a role in regulating inflammation in gastric mucosa. The aim of this study was to examine the possible role of group IIA phospholipase A2 in experimental Helicobacter infection. MATERIALS AND METHODS Transgenic mice expressing human group IIA phospholipase A2 and their group IIA phospholipase A2 deficient nontransgenic C57BL/6 J littermates were infected with H. felis. The mice were killed 3, 8, and 19 weeks after inoculation of bacteria to determine the histopathological changes in gastric mucosa. RESULTS The infected mice developed chronic inflammation in gastric mucosa. We found no differences in the colonization of bacteria between transgenic and nontransgenic mice. At 3 and 8 weeks, no difference was found in the severity of inflammation between the two groups. Nineteen weeks after the administration of bacteria the inflammation was more marked in nontransgenic than transgenic mice. Group IIA phospholipase A2 was expressed by in situ hybridization in the neck cells of the glandular stomach in transgenic mice. CONCLUSIONS The results of the present study suggest that the endogenous expression of group IIA phospholipase A2 diminishes chronic inflammation in gastric mucosa in experimental H. felis infection in mice.
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Affiliation(s)
- Heikki T Huhtinen
- Department of Surgery, University of Turku and Turku University Central Hospital, Turku, Finland.
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Jia W, El Zoeiby A, Petruzziello TN, Jayabalasingham B, Seyedirashti S, Bishop RE. Lipid trafficking controls endotoxin acylation in outer membranes of Escherichia coli. J Biol Chem 2004; 279:44966-75. [PMID: 15319435 DOI: 10.1074/jbc.m404963200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The biogenesis of biological membranes hinges on the coordinated trafficking of membrane lipids between distinct cellular compartments. The bacterial outer membrane enzyme PagP confers resistance to host immune defenses by transferring a palmitate chain from a phospholipid to the lipid A (endotoxin) component of lipopolysaccharide. PagP is an eight-stranded antiparallel beta-barrel, preceded by an N-terminal amphipathic alpha-helix. The active site is localized inside the beta-barrel and is aligned with the lipopolysaccharide-containing outer leaflet, but the phospholipid substrates are normally restricted to the inner leaflet of the asymmetric outer membrane. We examined the possibility that PagP activity in vivo depends on the aberrant migration of phospholipids into the outer leaflet. We find that brief addition to Escherichia coli cultures of millimolar EDTA, which is reported to replace a fraction of lipopolysaccharide with phospholipids, rapidly induces palmitoylation of lipid A. Although expression of the E. coli pagP gene is induced during Mg2+ limitation by the phoPQ two-component signal transduction pathway, EDTA-induced lipid A palmitoylation occurs more rapidly than pagP induction and is independent of de novo protein synthesis. EDTA-induced lipid A palmitoylation requires functional MsbA, an essential ATP-binding cassette transporter needed for lipid transport to the outer membrane. A potential role for the PagP alpha-helix in phospholipid translocation to the outer leaflet was excluded by showing that alpha-helix deletions are active in vivo. Neither EDTA nor Mg(2+)-EDTA stimulate PagP activity in vitro. These findings suggest that PagP remains dormant in outer membranes until Mg2+ limitation promotes the migration of phospholipids into the outer leaflet.
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Affiliation(s)
- Wenyi Jia
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
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Gimenez AP, Wu YZ, Paya M, Delclaux C, Touqui L, Goossens PL. High bactericidal efficiency of type iia phospholipase A2 against Bacillus anthracis and inhibition of its secretion by the lethal toxin. THE JOURNAL OF IMMUNOLOGY 2004; 173:521-30. [PMID: 15210813 DOI: 10.4049/jimmunol.173.1.521] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
There is a considerable body of evidence supporting the role of secretory type II-A phospholipase A(2) (sPLA(2)-IIA) as an effector of the innate immune response. This enzyme also exhibits bactericidal activity especially toward Gram-positive bacteria. In this study we examined the ability of sPLA(2)-IIA to kill Bacillus anthracis, the etiological agent of anthrax. Our results show that both germinated B. anthracis spores and encapsulated bacilli were sensitive to the bactericidal activity of recombinant sPLA(2)-IIA in vitro. In contrast, nongerminated spores were resistant. This bactericidal effect was correlated to the ability of sPLA(2)-IIA to hydrolyze bacterial membrane phospholipids. Guinea pig alveolar macrophages, the major source of sPLA(2)-IIA in an experimental model of acute lung injury, released enough sPLA(2)-IIA to kill extracellular B. anthracis. The production of sPLA(2)-IIA was significantly inhibited by B. anthracis lethal toxin. Human bronchoalveolar lavage fluids from acute respiratory distress syndrome patients are known to contain sPLA(2)-IIA; bactericidal activity against B. anthracis was detected in a high percentage of these samples. This anthracidal activity was correlated to the levels of sPLA(2)-IIA and was abolished by an sPLA(2)-IIA inhibitor. These results suggest that sPLA(2)-IIA may play a role in innate host defense against B. anthracis infection and that lethal toxin may help the bacteria to escape from the bactericidal action of sPLA(2)-IIA by inhibiting the production of this enzyme.
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Affiliation(s)
- Alejandro Piris Gimenez
- Unité Toxines et Pathogénie Bactérienne/Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 25 rue du Dr. Roux, Institut Pasteur, 75724 Paris Cedex 15, France
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Abstract
Venom phospholipase A2 (PLA2) enzymes share similarity in structure and catalytic function with mammalian enzymes. However, in contrast to mammalian enzymes, many are toxic and induce a wide spectrum of pharmacological effects. Thus structure-function relationship of this group of small proteins is subtle, but complex puzzle to protein biochemists, molecular biologists, toxinologists, pharmacologists and physiologists. This review describes the present status of our understanding of their structure, function and mechanism. It was proposed that their unique ability to 'target' themselves to a specific organ or tissue is due to their high affinity binding to specific proteins which act as receptors (more precisely, acceptors). This specific binding of PLA2 is conferred by the presence of a 'pharmacological site' on its surface which is independent of the catalytic site. The high affinity interaction of PLA2 with its acceptor (or target protein) is probably due to the complementarity, in terms of charges, hydrophobicity and van der Waal's contact surfaces, between the pharmacological site and the binding site on the surface of the acceptor protein. Upon binding to the target, the PLA2 can induce its pharmacological effects by mechanisms either dependent on or independent of its catalytic activity. Because of the unprecedented wide spectrum of specific targeting to various tissues and organs, identification of the pharmacological sites has potential for exploitation in development of novel systems useful for 'delivering' specific proteins to a particular target tissue or organ. Thus research in this field will provide a lot of exciting opportunities.
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Affiliation(s)
- R Manjunatha Kini
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543.
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Vracko J, Wiechel KL. Increased gallbladder trypsin in acute cholecystitis indicates functional disorder in the sphincter of oddi and could make EPT a logical procedure. Surg Laparosc Endosc Percutan Tech 2004; 13:308-13. [PMID: 14571164 DOI: 10.1097/00129689-200310000-00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Clinical and surgical observations confirm that acute cholecystitis (ACh) and acute biliary pancreatitis can coexist and that differentiation may be difficult even at surgery. Synchronous appearance of ACh and acute biliary pancreatitis suggests a similar etiology. Endoscopic sphincterotomy, with relief of the common channel outlet obstruction, has become the established therapeutical modality that improves the outcome in acute biliary pancreatitis. Patients suffering from ACh could be treated in a similar manner to prevent reflux of pancreatic juice into the common bile duct and the gallbladder with the intention to improve the clinical course. The present study investigated the presence and amount of pancreatic trypsin in the gallbladder bile in 73 patients operated on for gallstone disease with ACh and in controls. The average gallbladder bile trypsin level in the "edematous cholecystitis" group ranged between 0.525 and 4500 ng/mL, significantly exceeding that of controls, 0.5-53 ng/mL (P < 0.0001). The average gallbladder bile trypsin level in the "gangrenous cholecystitis" group, 0.1-71.5 ng/mL, was within the range of controls (n.s.), most likely to be explained as a consequence of consumption of trypsin due to the fulminant development of the disease. Further controlled studies are mandatory before it would be acceptable to recommend endoscopic sphincterotomy as a valuable choice in the initial/early management of patients suffering from ACh. Such a study is underway to assess the possible role of obstruction at, or other disorders of, the sphincter of Oddi with consequent pancreatic juice reflux into the gallbladder as a possible initial cause of ACh.
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Abstract
Secretory phospholipase A2 (sPLA2) is a growing family of structurally related, disulfide-rich, low molecular weight, lipolytic enzymes with a His-Asp catalytic dyad. sPLA2s are distributed in a wide variety of vertebrate and invertebrate animals, plants, bacteria, and viruses, and there are 10 catalytically active sPLA2 isozymes in mammals. Although the structural bases for mammalian sPLA2s have been well documented, their physiological functions are still subject to debate. Individual mammalian sPLA2s have distinct enzymatic properties and display distinct tissue expression patterns, suggesting that each enzyme acts on distinct phospholipid membrane moieties in vivo. In this article, we briefly review our latest understanding of the possible physiological functions of sPLA2s, in keeping with their diverse actions on mammalian and nonmammalian cell membranes.
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Affiliation(s)
- Makoto Murakami
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
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Tietge UJF, Maugeais C, Cain W, Rader DJ. Acute inflammation increases selective uptake of HDL cholesteryl esters into adrenals of mice overexpressing human sPLA2. Am J Physiol Endocrinol Metab 2003; 285:E403-11. [PMID: 12637261 DOI: 10.1152/ajpendo.00576.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The acute-phase protein secretory phospholipase A2 (sPLA2) influences the metabolism of high-density lipoproteins (HDL). The adrenals are known to utilize HDL cholesterol as a source of sterols. The aim of the present study was to test the hypothesis that sPLA2 enhances the selective uptake of HDL into the adrenals in response to acute inflammation as a possible physiological role for the sPLA2-HDL interaction. Human sPLA2-transgenic mice, in which sPLA2 expression is upregulated by inflammatory stimuli, were used. Ten hours after induction of the acute-phase response (APR) by injection of bacterial lipopolysaccharide (LPS), plasma levels of HDL cholesterol decreased significantly in sPLA2-transgenic mice (-18%, P < 0.05) but remained unchanged in wild-type mice. The fractional catabolic rates of both 125I-labeled tyraminecellobiose (TC)-HDL and [3H]cholesteryl ether increased significantly in the sPLA2-transgenic mice after induction of the APR (0.18 +/- 0.01 vs. 0.21 +/- 0.01 pool/h, P < 0.05, and 0.31 +/- 0.02 vs. 0.42 +/- 0.05 pool/h, P < 0.05, respectively) but remained unchanged in the wild-type mice (0.10 +/- 0.01 vs. 0.22 +/- 0.02 pool/h, respectively). After induction of the APR, in both groups HDL holoparticle uptake by the liver was increased (P < 0.001). sPLA2-transgenic mice had 2.4-fold higher selective uptake into the adrenals after induction of the APR than wild-type mice (156 +/- 6 vs. 65 +/- 5%/ micro g tissue protein, P < 0.001). In summary, upregulation of sPLA2 expression during the APR specifically increases the selective uptake of HDL cholesteryl ester into the adrenals. These data suggest a novel metabolic role for sPLA2: modification of HDL during the APR to promote increased adrenal uptake of HDL cholesteryl ester to serve as source for steroid hormone synthesis.
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Affiliation(s)
- Uwe J F Tietge
- Univ. of Pennsylvania Medical Center, 654 BRB II/III, 421 Curie Blvd., Philadelphia, PA 19104-6160, USA.
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Posadas I, Terencio MC, Randazzo A, Gomez-Paloma L, Payá M, Alcaraz MJ. Inhibition of the NF-kappaB signaling pathway mediates the anti-inflammatory effects of petrosaspongiolide M. Biochem Pharmacol 2003; 65:887-95. [PMID: 12628480 DOI: 10.1016/s0006-2952(02)01659-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Petrosaspongiolide M (PT) is a potent secretory phospholipase A(2) inhibitor and anti-inflammatory agent. This marine metabolite reduced the production of nitrite, prostaglandin E(2), and tumor necrosis factor-alpha in the mouse air pouch injected with zymosan. These effects were also observed in mouse peritoneal macrophages stimulated with zymosan. Inhibition of these inflammatory mediators was related to reductions in inducible nitric oxide synthase, cyclo-oxygenase-2, and tumor necrosis factor-alpha expression. Since nuclear factor-kappaB (NF-kappaB) appears to play a central role in the transcriptional regulation of these proteins by macrophages, we investigated the effects of PT on this transcription factor. We found that PT was a potent inhibitor of the NF-kappaB pathway since at 1 microM it strongly decreased NF-kappaB-DNA binding in response to zymosan, in mouse peritoneal macrophages. Our study also indicated that PT could interfere with a key step in NF-kappaB activation, the phosphorylation of IkappaBalpha, resulting in inhibition of IkappaBalpha degradation. The control of a wide range of mediators by PT suggests a potentially wide therapeutic spectrum for this marine metabolite in inflammatory conditions.
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Affiliation(s)
- Inmaculada Posadas
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Valencia, Avda. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain
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46
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Cieslik K, Zhu Y, Wu KK. Salicylate suppresses macrophage nitric-oxide synthase-2 and cyclo-oxygenase-2 expression by inhibiting CCAAT/enhancer-binding protein-beta binding via a common signaling pathway. J Biol Chem 2002; 277:49304-10. [PMID: 12379662 DOI: 10.1074/jbc.m205030200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We determined whether salicylate at pharmacological concentrations inhibits nitric-oxide synthase-2 (NOS-2) and cyclo-oxygenase-2 (COX-2) expressions in RAW 264.7 stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Cells were treated with sodium salicylate (10(-7)-10(-4) m) or vehicle for 30 min followed by LPS+IFN-gamma for up to 24 h. Salicylate suppressed NOS-2 and COX-2 protein levels and promoter activities stimulated by LPS+IFN-gamma for 4 h in a concentration-dependent manner but had no effect on NOS-2 expression stimulated by the combined agonists for 24 h. Results from promoter analysis indicate that the binding of CCAAT/enhancer-binding protein beta (C/EBPbeta) to its cognate site at -150/-142 on the NOS-2 promoter region was essential for NOS-2 expression at 4 h but not at 24 h. Salicylate reduced C/EBPbeta binding at 4 h and did not alter its binding at 24 h. NOS-2 and COX-2 protein levels and C/EBPbeta binding stimulated by LPS+IFN-gamma for 4 h were inhibited by a similar battery of signaling inhibitors, suggesting a common pathway for NOS-2 and COX-2 expression. Kinetic analysis indicates that NOS-2, similar to COX-2 expression, at 4 h was largely due to the action of LPS, which induced C/EBPbeta binding, whereas its expression at a longer time point was contributed by IFN-gamma. Our findings implicate two distinct pathways for NOS-2 expression induced by LPS+IFN-gamma. Salicylate at pharmacological concentrations is capable of suppressing the early phase of NOS-2 and COX-2 expression by blocking C/EBPbeta binding.
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Affiliation(s)
- Katarzyna Cieslik
- Vascular Biology Research Center, Institute of Molecular Medicine and Division of Hematology, University of Texas-Houston Health Science Center, 6431 Fannin, Houston, TX 77030, USA
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Koprivnjak T, Peschel A, Gelb MH, Liang NS, Weiss JP. Role of charge properties of bacterial envelope in bactericidal action of human group IIA phospholipase A2 against Staphylococcus aureus. J Biol Chem 2002; 277:47636-44. [PMID: 12359734 DOI: 10.1074/jbc.m205104200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian Group IIA phospholipases A(2) (PLA(2)) potently kill Staphylococcus aureus. Highly cationic properties of these PLA(2) are important for Ca(2+)-independent binding and cell wall penetration, prerequisites for Ca(2+)-dependent degradation of membrane phospholipids and bacterial killing. To further delineate charge properties of the bacterial envelope important in Group IIA PLA(2) action against S. aureus, we examined the effects of mutations that prevent specific modifications of cell wall (dltA) and cell membrane (mprF) polyanions. In comparison to the parent strain, isogenic dltA(-) bacteria are approximately 30-100x more sensitive to PLA(2), whereas mprF(-) bacteria are <3-fold more sensitive. Differences in PLA(2) sensitivity of intact bacteria reflect differences in cell wall, not cell membrane, properties since protoplasts from all three strains are equally sensitive to PLA(2). A diminished positive charge in PLA(2) reduces PLA(2) binding and antibacterial activity. In contrast, diminished cell wall negative charge by substitution of (lipo)teichoic acids with d-alanine reduces antibacterial activity of bound PLA(2), but not initial PLA(2) binding. Therefore, the potent antistaphylococcal activity of Group IIA PLA(2) depends on cationic properties of the enzyme that promote binding to the cell wall, and polyanionic properties of cell wall (lipo)teichoic acids that promote attack of membrane phospholipids by bound PLA(2).
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Affiliation(s)
- Tomaz Koprivnjak
- Department of Microbiology, University of Iowa, Iowa City Veterans Affairs Medical Center, Iowa City, Iowa 52246, USA
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Fuentes L, Hernández M, Nieto ML, Sánchez Crespo M. Biological effects of group IIA secreted phosholipase A(2). FEBS Lett 2002; 531:7-11. [PMID: 12401194 DOI: 10.1016/s0014-5793(02)03401-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Group IIA secreted phospholipase A(2) (sPLA(2)-IIA) is the most abundant element in human tissues of a large family of low molecular weight phospholipases A(2), which shows properties different from those displayed by the cytosolic phospholipase A(2) involved in the release of arachidonic acid. sPLA(2)-IIA behaves as a ligand for a group of receptors inside the C-type multilectin mannose receptor family and also interacts with heparan sulfate proteoglycans such as glypican, the dermatan/chondroitin sulfate-rich decorin, and the chondroitin sulfate-rich versican, thus being able to internalize to specific compartments within the cell and producing biological responses. This review provides a short summary of the biological actions of sPLA(2)-IIA on intracellular signaling pathways.
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Affiliation(s)
- Lucía Fuentes
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Facultad de Medicina, 47005, Valladolid, Spain
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Abstract
Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid (AA), a precursor of eicosanoids including prostaglandins and leukotrienes. The same reaction also produces lysophosholipids, which represent another class of lipid mediators. So far, at least 19 enzymes that possess PLA2 activity have been identified and cloned in mammals. The secretory PLA2 (sPLA2) family, in which 10 isozymes have been identified, consists of low-molecular weight, Ca2+-requiring secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, and host defense. The cytosolic PLA2 (cPLA2) family consists of three enzymes, among which cPLA2alpha has been paid much attention by researchers as an essential component of the initiation of AA metabolism. The activation of cPLA2alpha is tightly regulated by Ca2+ and phosphorylation. The Ca2+-independent PLA2 (iPLA2) family contains two enzymes and may play a major role in phospholipid remodeling. The platelet-activating factor (PAF) acetylhydrolase (PAF-AH) family contains four enzymes that exhibit unique substrate specificity toward PAF and/or oxidized phospholipids. Degradation of these bioactive phospholipids by PAF-AHs may lead to the termination of inflammatory reaction and atherosclerosis.
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Affiliation(s)
- Ichiro Kudo
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
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Murakami M, Yoshihara K, Shimbara S, Lambeau G, Singer A, Gelb MH, Sawada M, Inagaki N, Nagai H, Kudo I. Arachidonate release and eicosanoid generation by group IIE phospholipase A(2). Biochem Biophys Res Commun 2002; 292:689-96. [PMID: 11922621 DOI: 10.1006/bbrc.2002.6716] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The heparin-binding group II subfamily of secretory phospholipase A(2)s (sPLA(2)s), such as sPLA(2)-IIA and -IID, augments stimulus-induced arachidonic acid (AA) release through the cellular heparan sulfate proteoglycan (HSPG)-dependent pathway when transfected into HEK293 cells. Here we show that the closest homolog, sPLA(2)-IIE, also promotes stimulus-induced AA release and prostaglandin (PG) production similar to those elicited by HSPG-dependent sPLA(2)s. Confocal laser microscopic analysis demonstrates the location of sPLA(2)-IIE in cytoplasmic punctate compartments. sPLA(2)-IIE also enhances leukotriene (LT) production and granule exocytosis by RBL-2H3 mastocytoma cells. Expression of sPLA(2)-IIE was highly upregulated in mice injected with lipopolysaccharide (LPS) and in mice with experimental atopic dermatitis. These observations suggest that this enzyme plays a role in the inflammatory process, as proposed for other group II subfamily sPLA(2)s.
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Affiliation(s)
- Makoto Murakami
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
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