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Valdés S, Paredes SD, García Carreras C, Zuluaga P, Rancan L, Linillos-Pradillo B, Arias-Díaz J, Vara E. S-Adenosylmethionine Decreases Bacterial Translocation, Proinflammatory Cytokines, Oxidative Stress and Apoptosis Markers in Hepatic Ischemia-Reperfusion Injury in Wistar Rats. Antioxidants (Basel) 2023; 12:1539. [PMID: 37627534 PMCID: PMC10451188 DOI: 10.3390/antiox12081539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/22/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023] Open
Abstract
Hepatic ischemia/reperfusion injury (IRI) can seriously impair liver function. It is initiated by oxidative stress, resulting in inflammation and apoptosis-induced cellular damage. Glutathione (GSH) prevents oxidative stress. S-Adenosylmethionine (SAMet) is a GSH synthesis precursor that avoids the deficit in SAMet-synthetase activity and contributes to intracellular ATP repletion. It also acts as a methyl group donor, stabilizing hepatocyte membranes, among other functions. This study investigated the effect of SAMet on bacterial translocation and levels of proinflammatory cytokines, oxidative stress and apoptosis markers in male Wistar rats subjected to hepatic IRI. Animals were randomly divided into six groups: (1) sham operation, (3) animals undergoing 60 min of ischemia of the right lateral lobe for temporary occlusion of the portal vein and hepatic artery plus 10 min of reperfusion, and (5) the same as (3) but with a reperfusion period of 120 min. Groups 2, 4 and 6, respectively, are the same as (1), (3) and (5), except that animals received SAMet (20 mg/kg) 15 min before ischemia. GSH, ATP, lipid peroxidation (LPO), TNF-α, IL-1β, IL-6, total caspase-1 and caspase-9, total and cleaved caspase-3, and phosphatidylcholine were determined in the liver. Endotoxin, TNF-α, IL-1β, IL-6, IL-10 and LPO in vena cava and portal vein blood samples were also measured. Endotoxin and LPO levels as well as proinflammatory cytokines and apoptotic markers increased significantly in animals undergoing IRI, both after 10 and 120 min of reperfusion. IRI produced a significant decrease in GSH, ATP, portal IL-10 and phosphatidylcholine. SAMet treatment prevented these effects significantly and increased survival rate. The study suggests that SAMet exerts protective effects in hepatic IRI.
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Affiliation(s)
- Sergio Valdés
- Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain; (S.V.); (C.G.C.); (L.R.); (B.L.-P.); (E.V.)
| | - Sergio D. Paredes
- Department of Physiology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain
| | - Carmen García Carreras
- Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain; (S.V.); (C.G.C.); (L.R.); (B.L.-P.); (E.V.)
| | - Pilar Zuluaga
- Departmental Unit of Biostatistics—Department of Statistics and Operations Research, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain;
| | - Lisa Rancan
- Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain; (S.V.); (C.G.C.); (L.R.); (B.L.-P.); (E.V.)
| | - Beatriz Linillos-Pradillo
- Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain; (S.V.); (C.G.C.); (L.R.); (B.L.-P.); (E.V.)
| | - Javier Arias-Díaz
- Department of Surgery, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain;
| | - Elena Vara
- Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Avda. Complutense, s/n, 28040 Madrid, Spain; (S.V.); (C.G.C.); (L.R.); (B.L.-P.); (E.V.)
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Rauckhorst AJ, Broekemeier KM, Pfeiffer DR. Regulation of the Ca(2+)-independent phospholipase A2 in liver mitochondria by changes in the energetic state. J Lipid Res 2014; 55:826-36. [PMID: 24586040 DOI: 10.1194/jlr.m043307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of electron transport chain redox status on activity of the mitochondrial Ca(2+)-independent phospholipase A2 (iPLA2) has been examined. When oxidizing NAD-linked substrates, the enzyme is not active unless deenergization occurs. Uncoupler, rotenone, antimycin A, and cyanide are equally effective at upregulating the enzyme, while oligomycin is ineffective. Thenoyltrifluoroacetone causes deenergization and activates the enzyme, but only if succinate is the respiratory substrate. These findings show that the mitochondrial iPLA2 responds to the energetic state overall, rather than to the redox status of individual electron transport chain complexes. With NAD-linked substrates, and using rotenone to deenergize, iPLA2 activation can be reversed by adding succinate to reestablish a membrane potential. For this purpose, ascorbate plus N,N,N'N'-tetramethyl-phenylenediamine can be used instead of succinate and is equally effective. With succinate as substrate, the membrane potential can be reduced in a graded and stable fashion by adding increasing concentrations of malonate, which is a competitive inhibitor of succinate utilization. A partial and stable activation of the iPLA2 accompanies partial deenergization. These findings suggest that in addition to the several functions that have been proposed, the mitochondrial iPLA2 may help to coordinate local capillary blood flow with changing energy demands.
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Affiliation(s)
- Adam J Rauckhorst
- Departments of Molecular and Cellular Biochemistry Ohio State University, Columbus, OH 43210
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Astiz M, de Alaniz MJT, Marra CA. Effect of pesticides on cell survival in liver and brain rat tissues. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2009; 72:2025-2032. [PMID: 19493570 DOI: 10.1016/j.ecoenv.2009.05.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/16/2009] [Accepted: 05/01/2009] [Indexed: 05/27/2023]
Abstract
Pesticides are the main environmental factor associated with the etiology of human neurodegenerative disorders such as Parkinson's disease. Our laboratory has previously demonstrated that the treatment of rats with low doses of dimethoate, zineb or glyphosate alone or in combination induces oxidative stress (OS) in liver and brain. The aim of the present work was to investigate if the pesticide-induced OS was able to affect brain and liver cell survival. The treatment of Wistar rats with the pesticides (i.p. 1/250 LD50, three times a week for 5 weeks) caused loss of mitochondrial transmembrane potential and cardiolipin content, especially in substantia nigra (SN), with a concomitant increase of fatty acid peroxidation. The activation of calpain apoptotic cascade (instead of the caspase-dependent pathway) would be responsible for the DNA fragmentation pattern observed. Thus, these results may contribute to understand the effect(s) of chronic and simultaneous exposure to pesticides on cell survival.
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Affiliation(s)
- Mariana Astiz
- INIBIOLP (Instituto de Investigaciones Bioquímicas de La Plata), CCT La Plata, CONICET-UNLP, Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120 (1900) La Plata, Argentina.
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4
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Caro AA, Cederbaum AI. Role of phospholipase A2 activation and calcium in CYP2E1-dependent toxicity in HepG2 cells. J Biol Chem 2003; 278:33866-77. [PMID: 12813050 DOI: 10.1074/jbc.m300408200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies suggested a role for calcium in CYP2E1-dependent toxicity. The possible role of phospholipase A2 (PLA2) activation in this toxicity was investigated. HepG2 cells that overexpress CYP2E1 (E47 cells) exposed to arachidonic acid (AA) +Fe-NTA showed higher toxicity than control HepG2 cells not expressing CYP2E1 (C34 cells). This toxicity was inhibited by the PLA2 inhibitors aristolochic acid, quinacrine, and PTK. PLA2 activity assessed by release of preloaded [3H]AA after treatment with AA+Fe was higher in the CYP2E1 expressing HepG2 cells. This [3H]AA release was inhibited by PLA2 inhibitors, alpha-tocopherol, and by depleting Ca2+ from the cells (intracellular + extracellular sources), but not by removal of extracellular calcium alone. Toxicity was preceded by an increase in intracellular calcium caused by influx from the extracellular space, and this was prevented by PLA2 inhibitors. PLA2 inhibitors also blocked mitochondrial damage in the CYP2E1-expressing HepG2 cells exposed to AA+Fe. Ca2+ depletion and removal of extracellular calcium inhibited toxicity at early time periods, although a delayed toxicity was evident at later times in Ca2+-free medium. This later toxicity was also inhibited by PLA2 inhibitors. Analogous to PLA2 activity, Ca2+ depletion but not removal of extracellular calcium alone prevented the activation of calpain activity by AA+Fe. These results suggest that release of stored calcium by AA+Fe, induced by lipid peroxidation, can initially activate calpain and PLA2 activity, that PLA2 activation is critical for a subsequent increased influx of extracellular Ca2+, and that the combination of increased PLA2 and calpain activity, increased calcium and oxidative stress cause mitochondrial damage, that ultimately produces the rapid toxicity of AA+Fe in CYP2E1-expressing HepG2 cells.
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Affiliation(s)
- Andres A Caro
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029, USA
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5
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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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6
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Jaross W, Eckey R, Menschikowski M. Biological effects of secretory phospholipase A(2) group IIA on lipoproteins and in atherogenesis. Eur J Clin Invest 2002; 32:383-93. [PMID: 12059982 DOI: 10.1046/j.1365-2362.2002.01000.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Secretory phospholipase A(2) group IIA(sPLA(2) IIA) can be produced and secreted by various cell types either constitutionally or as an acute-phase reactant upon stimulation by proinflammatory cytokines. The enzyme prefers phosphatidylethanolamine and phosphatidylserine as substrates. One important biological function may be the hydrolytic destruction of bacterial membranes. It has been demonstrated, however, that sPLA(2) can also hydrolyse the phospholipid monolayers of high density lipoprotein (HDL) and low density lipoprotein (LDL) in vitro. Secretory phospholipase A(2)-modified LDL show increased affinity to glycosaminoglycans and proteoglycans, a tendency to aggregate, and an enhanced ability to deliver cholesterol to cells. Incubation of cultured macrophages with PLA(2)-treated LDL and HDL is associated with increased intracellular lipid accumulation, resulting in the formation of foam cells. Elevated sPLA(2)(IIA) activity in blood serum leads to an increased clearance of serum cholesterol. Secretory phospholipase A(2)(IIA) can also be detected in the intima, adventitia and media of the atherosclerotic wall not only in developed lesions but also in very early stages of atherosclerosis. The presence of DNA of Chlamydia pneumoniae, herpes simplex virus, and cytomegalovirus was found to be associated with sPLA(2)(IIA) expression and other signs of local inflammation. Thus, sPLA(2)(IIA) appears to be one important link between the lipid and the inflammation hypothesis of atherosclerosis.
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Affiliation(s)
- Werner Jaross
- Institute for Clinical Chemistry and Laboratory Medicine, Medical Faculty, Technical University of Dresden, Germany.
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7
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Affiliation(s)
- M Murakami
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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8
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Nevalainen TJ, Haapamäki MM, Grönroos JM. Roles of secretory phospholipases A(2) in inflammatory diseases and trauma. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:83-90. [PMID: 11080679 DOI: 10.1016/s1388-1981(00)00112-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Six distinct secretory small molecular weight phospholipases A(2) (PLA(2)) have been cloned and characterized from human tissues. Two of them, pancreatic group IB PLA(2) (PLA(2)-IB) and synovial-type group IIA PLA(2) (PLA(2)-IIA) have been studied as to their association to various inflammatory diseases. PLA(2)-IB is a digestive enzyme synthesized by pancreatic acinar cells. In acute pancreatitis, which is characterized by destruction of pancreatic tissue, PLA(2)-IB is released into the circulation, but its role in pancreatic and other tissue damage is still hypothetical. The concentration of PLA(2)-IIA increases in blood plasma in generalized inflammatory response resulting from infections, chronic inflammatory diseases, acute pancreatitis, trauma and surgical operations. PLA(2)-IIA is synthesized in a number of gland cells and is present in cellular secretions on mucosal surfaces including Paneth cells of intestinal mucosa, prostatic gland cells and seminal plasma, and lacrimal glands and tears. PLA(2)-IIA is expressed in hepatoma-derived cells in vitro and hepatocytes in vivo. PLA(2)-IIA is regarded as an acute phase protein and seems to function as an antibacterial agent especially effective against Gram-positive bacteria. Other putative functions in the inflammatory reaction include hydrolysis of cell membrane phospholipids and release of arachidonic acid for prostanoid synthesis.
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Affiliation(s)
- T J Nevalainen
- Department of Pathology, University of Turku and Turku University Hospital, Finland.
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9
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Kern H, Johnen W, Braun J, Frey B, Rüstow B, Kox WJ, Schlame M. Heparin induces release of phospholipase A(2) into the splanchnic circulation. Anesth Analg 2000; 91:528-32. [PMID: 10960370 DOI: 10.1097/00000539-200009000-00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Cardiopulmonary bypass results in increased plasma activity of phospholipase A(2) (PLA(2)) that appears to be caused by the administration of heparin. High PLA(2) activity may be responsible for increased production of eicosanoids and, thus, may be implicated in various pathophysiologic events associated with cardiac surgery. To investigate the site of PLA(2) secretion, blood samples were simultaneously collected from the radial artery, the pulmonary artery, and the hepatic vein at 2, 4, 6, and 20 min after systemic heparinization (350 U/kg). Within 2 min of the heparin injection, plasma activity of PLA(2) increased 4- to 9-fold and remained so for at least 20 min. Two minutes after the heparin injection, PLA(2) was significantly higher in the hepatic vein than in the radial artery (P: < 0.01). No such difference was detected between pulmonary and radial arteries. When heparin was added to blood samples in vitro (5-100 U/mL), plasma activity of PLA(2) did not increase, which suggests that the enzyme was not secreted by blood cells. IMPLICATIONS Heparin, given in the dosage required for cardiopulmonary bypass, caused release of phospholipase A(2) into the splanchnic circulation.
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Affiliation(s)
- H Kern
- Departments of Anesthesiology and Intensive Care Medicine and Neonatology, University Hospital Charité, Humboldt University, Berlin, Germany
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10
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Kern H, Johnen W, Braun J, Frey B, Rüstow B, Kox WJ, Schlame M. Heparin Induces Release of Phospholipase A2 into the Splanchnic Circulation. Anesth Analg 2000. [DOI: 10.1213/00000539-200009000-00005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Harry D, Anand R, Holt S, Davies S, Marley R, Fernando B, Goodier D, Moore K. Increased sensitivity to endotoxemia in the bile duct-ligated cirrhotic Rat. Hepatology 1999; 30:1198-205. [PMID: 10534341 DOI: 10.1002/hep.510300515] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Sepsis is a common complication of cirrhosis with a high mortality. In this study, we have investigated some of the pathways that may be involved in tissue injury and death. Bile duct-ligated (BDL) cirrhotic and control rats were challenged with lipopolysaccharide (LPS). Sensitivity to LPS was markedly enhanced in the BDL group, and was associated with increased liver injury and mortality. There was a 5-fold constitutive activation of nuclear factor kappa B (NFkappaB) in the liver of BDL rat controls (P <.001), and this was activated further, but to a similar extent, in the liver of both sham and BDL rats after injection of LPS. Plasma tumor necrosis factor alpha (TNF-alpha) increased more markedly in the BDL cirrhotic rats (2,463 +/- 697 pg/mL in BDL rats versus 401 +/- 160 pg/mL in the controls at 3 hours; P <.01). Plasma nitrite/nitrate concentrations were increased in the BDL controls at baseline, and increased further after LPS (P <.05), but did not differ from sham controls at 6 hours. Plasma F(2)-isoprostanes increased 6-fold in the cirrhotic rats and 2-fold in the controls (P <.01) indicative of lipid peroxidation. Esterified F(2)-isoprostanes in the liver increased 2- to 3-fold at 1 hour in control and BDL rats, but returned to baseline levels by 3 hours. Esterified F(2)-isoprostanes in the kidney increased by 2-fold in the BDL rats after LPS administration, but remained unchanged in sham controls. We conclude that there is a marked increase in sensitivity to LPS in BDL cirrhotic rats. This is associated with an enhanced TNF-alpha response and increased lipid peroxidation. These may be directly and causally related to mortality.
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Affiliation(s)
- D Harry
- Department of Medicine, Royal Free and University College Hospital School of Medicine, Royal Free Campus, Pond Street, London, UK
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Zhang Y, Lemasters J, Herman B. Secretory group IIA phospholipase A(2) generates anti-apoptotic survival signals in kidney fibroblasts. J Biol Chem 1999; 274:27726-33. [PMID: 10488115 DOI: 10.1074/jbc.274.39.27726] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian group IIA phospholipase A(2) (PLA(2)) is believed to play important roles in inflammation, cell injury, and tumor resistance. However, the cellular site of action has not been clearly defined as it has long been recognized that group IIA PLA(2) is both a secretory and mitochondrial protein. The purpose of this study was to determine the subcellular target of the group IIA PLA(2) and its role in apoptosis stimulated by growth factor withdrawal. Cloning of the rat liver group IIA PLA(2) demonstrated a typical secretory signal and no alternative splicing of the primary transcript. When a sequence including the signal peptide and first 8 residues in the mature enzyme or the entire PLA(2) (including the signal peptide) was fused to enhanced green fluorescent protein, the fusion protein was directed to the secretory pathway rather than mitochondria in baby hamster kidney (BHK) cells. To examine the role of group IIA PLA(2) in cell injury, wild type (wt) rat group IIA PLA(2) and a mutant group IIA PLA(2) containing a His-47 --> Gln mutation (at the catalytic center) were transfected into BHK cells and cells stably expressing these constructs were isolated. After deprivation of growth factors, both normal BHK cells and BHK cells expressing mutant PLA(2) underwent massive apoptosis, while BHK cells expressing wt PLA(2) showed considerable resistance to growth factor withdrawal-induced apoptosis. The secretory PLA(2) inhibitors 12-epi-scalaradial and aristolochic acid abrogated resistance to apoptosis in the wt PLA(2) expressing cells. These two inhibitors did not induce cell death in the presence of fetal bovine serum, suggesting that they induce cell death by blocking PLA(2) generated survival signals. This study demonstrates that group IIA PLA(2) generates anti-apoptotic survival signals in BHK cells targeting the secretory pathway, and suggests that high levels of group IIA PLA(2) accumulated at inflammatory sites may not only regulate inflammation, but also may protect cells from unnecessary death induced by pro-inflammatory agents.
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Affiliation(s)
- Y Zhang
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284-7762, USA
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Abstract
Phospholipase A2 (PLA2) is an enzyme that catalyzes the hydrolysis of membrane phospholipids. This article reviews the source and structure of PLA2, the involvement of the enzyme in various biological and pathological phenomena, and the usefulness of PLA2 assays in laboratory diagnostics. Of particular importance is the role of PLA2 in the cellular production of mediators of inflammatory response to various stimuli. Assays for PLA2 activity and mass concentration are discussed, and the results of enzyme determinations in plasma from patients with different pathological conditions are presented. The determination of activity and mass concentration in plasma is particularly useful in the diagnosis and prognosis of pancreatitis, multiple organ failure, septic shock, and rheumatoid arthritis. A very important result is the demonstration that PLA2 is an acute phase protein, like CRP. Indeed, there is a close correlation between PLA2 mass concentration and CRP levels in several pathological conditions. Although the determination of C-reactive protein is much easier to perform and is routinely carried out in most clinical laboratories, the assessment of PLA2 activity or mass concentration has to be considered as a reliable approach to obtain a deeper understanding of some pathological conditions and may offer additional information concerning the prognosis of several disorders.
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Affiliation(s)
- E Kaiser
- Department of Medical Chemistry, University of Vienna, Austria
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Papa S, Skulachev VP. Reactive oxygen species, mitochondria, apoptosis and aging. Mol Cell Biochem 1997; 174:305-19. [PMID: 9309704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this paper, we shall review various antioxygen defense systems of the cell paying particular attention to those that prevent superoxide formation rather than scavenge already formed superoxide and its products. The role of uncoupled, decoupled and non-coupled respiration, mitochondrial pore, mitochondrion-linked apoptosis will be considered. Mitochondrial theory of aging will be regarded in context of reactive oxygen species-induced damage of mitochondrial DNA.
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Affiliation(s)
- S Papa
- Institute of Medical Biochemistry and Chemistry, University of Bari, Italy
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Marinho HS, Antunes F, Pinto RE. Role of glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase in the reduction of lysophospholipid hydroperoxides. Free Radic Biol Med 1997; 22:871-83. [PMID: 9119256 DOI: 10.1016/s0891-5849(96)00468-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
1-linoleoyl lysophosphatidylcholine hydroperoxide is a substrate of GSH peroxidase (GPx) both purified from bovine erythrocytes and nonpurified from rat liver. The initial reaction rate for bovine erythrocyte GPx with 1-linoleoyl lysophosphatidylcholine hydroperoxide is about 76 and 95% of the reaction rate for hydrogen peroxide and linoleic acid hydroperoxide respectively. For rat liver GPx these initial reaction rates are about 66 and 75%, respectively. The rate constants for the reaction of GPx with 1-linoleoyl lysophosphatidylcholine hydroperoxide were calculated to be approximately 3 x 10(7) M-1s-1 and approximately 2 x 10(6) M-1s-1 for the bovine erythrocyte and the rat liver enzymes, respectively. By using kinetic models of lipid peroxidation we found by simulation that: (1) the main source of lysophospholipid hydroperoxides in vivo is the peroxidation of lysophospholipids, both in mitochondrial inner membranes and in endoplasmic reticulum; (2) a specialized enzyme able to reduce directly lysophospholipid hydroperoxides is important for the reduction of these hydroperoxides, because the detoxification of these species mediated by the action of acyl ester bond cleaving enzymes is not efficient; (3) the reduction through GPx predominates over phospholipid hydroperoxide glutathione peroxidase (PHGPx) in mitochondrial inner membranes and in the cytosolic phase of the endoplasmic reticulum; (4) in the luminal phase of endoplasmic reticulum PHGPx is predominant.
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Affiliation(s)
- H S Marinho
- Departamento de Quimica e Bioquimica, Faculdade de Ciências, Universidade de Lisboa, Portugal
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Affiliation(s)
- S Papa
- Institute of Medical Biochemistry and Chemistry, University of Bari, Italy
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Othman R, Baker S, Li Y, Worrall AF, Wilton DC. Human non-pancreatic (group II) secreted phospholipase A2 expressed from a synthetic gene in Escherichia coli: characterisation of N-terminal mutants. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1303:92-102. [PMID: 8856038 DOI: 10.1016/0005-2760(96)00083-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A gene coding for human non-pancreatic (group II) secreted phospholipase A2 (hnpsPLA2) has been constructed by the single-step ligation of twelve synthetic oligonucleotides. The gene has been cloned into a modification of the bacterial expression vector pET 11 which allows protein over-expression as inclusion bodies and enables about 3 mg/litre of pure refolded fully active enzyme to be obtained. The protein was expressed as a 1-Ala mutant (N1A) to allow removal of the initiator methionine by the Escherichia coli amino-peptidase. This mutant had very similar properties to the wild-type enzyme. A double mutant, N1A, V3W was also constructed and expressed in high yield. This tryptophan-containing mutant showed similar properties to the wild-type and N1A mutant but had about 40% of the activity under the assay conditions used. This tryptophan was used as a reporter group for interfacial binding and its properties were compared to those of the corresponding tryptophan in PLA2 from procine pancreas. Expression of the wild-type gene sequence for hnpsPLA2 in E. coli gave the expected mutant protein still with the initiator methionine and with much reduced activity. Interfacial binding of all hnpsPLA2 mutants to anionic phospholipids was very similar when assessed by fluorescence methods. Comparisons of these mutants with the pancreatic enzyme revealed significant differences in terms of the effect of calcium on interfacial binding. The ability to express reasonably large amounts of the N1A mutant in E. coli will provide a basis for future site directed mutagenesis studies of this important human enzyme.
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Affiliation(s)
- R Othman
- Department of Biochemistry, University of Southampton, Bassett Crescent East, UK
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Papa S. Mitochondrial oxidative phosphorylation changes in the life span. Molecular aspects and physiopathological implications. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1276:87-105. [PMID: 8816944 DOI: 10.1016/0005-2728(96)00077-1] [Citation(s) in RCA: 202] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S Papa
- Institute of Medical Biochemistry and Chemistry, University of Bari, Italy.
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Cheng P, Dolinsky V, Hatch GM. The acylation of lysophosphatidylglycerol in rat heart: evidence for both in vitro and in vivo activities. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1302:61-8. [PMID: 8695656 DOI: 10.1016/0005-2760(96)00012-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The reacylation of lysophospholipids back to their parent molecules is important for attaining the appropriate fatty acyl composition in many phospholipids and for preventing the accumulation of arrhythmia generating lysophospholipids in the heart. In this study, we report the presence of an active acyltransferase activity for lysophosphatidylglycerol reacylation to phosphatidylglycerol in rat heart membrane preparations. The activity of acyl-Coenzyme A:1-acylglycerophosphorylglycerol acyltransferase in rat heart subcellular fractions was in the order of microsomal > mitochondrial > cytosol. The activity in the membrane fractions were characterized and found to have a pH optimum in the alkaline range. However, significant enzyme activity was observed at physiological pH. With oleoyl-Coenzyme A as substrate, the microsomal activity had a preference for lysophosphatidylglycerol substrates in the order of myristoyl > palmitoyl > oleoyl > stearoyl. The apparent K(m) values for 1-palmitoylglycerophosphorylglycerol and oleoyl-Coenzyme A were 9.4 and 7.1 microM, respectively. In contrast, the mitochondrial activity had a preference for lysophosphatidylglycerol substrates in the order of oleoyl > myristoyl = stearoyl = palmitoyl. The apparent K(m) values for 1-oleoylglycerophosphorylglycerol and oleoyl-Coenzyme A were 17.8 and 18.0 microM, respectively. Both membrane activities were heat labile as pre-incubation at 55 degrees C for 1 min completely abolished the activity. However, pre-incubation at 50 degrees C resulted in different profiles of inactivation in both microsomal and mitochondrial fractions. Both membrane activities were inhibited by high concentrations of lysophosphatidylglycerol and affected to a similar extent by various detergents. To demonstrate whether reacylation of lysophosphatidylglycerol to phosphatidylglycerol occurred in vivo, isolated rat hearts were perfused for 60 min in the Langendorff mode with 0.1 microM 1-palmitoylglycerophosphoryl[14C]glycerol bound to albumin. 1-Palmitoylglycerophosphoryl[14C]glycerol was readily taken up by the isolated perfused rat heart and significant synthesis of phosphatidyl[14C]glycerol was observed. The findings indicate the presence of an acyl-Coenzyme A:1-acylglycerophosphorylglycerol acyltransferase activity in the rat heart subcellular membranes which is capable of catalyzing lysophosphatidylglycerol acylation to phosphatidylglycerol in vitro and in vivo.
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Affiliation(s)
- P Cheng
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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SHORT COMMUNICATION. Clin Chem Lab Med 1996. [DOI: 10.1515/cclm.1996.34.5.419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Antunes F, Salvador A, Pinto RE. PHGPx and phospholipase A2/GPx: comparative importance on the reduction of hydroperoxides in rat liver mitochondria. Free Radic Biol Med 1995; 19:669-77. [PMID: 8529927 DOI: 10.1016/0891-5849(95)00040-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The comparative importance of phospholipid hydroperoxide glutathione peroxidase (PHGPx) and of "classic" glutathione peroxidase (GPx) in the reduction of phospholipid hydroperoxides is unclear. Although GPx activity is 500-fold higher than that of PHGPx in rat liver, the reduction of phospholipid hydroperoxides by glutathione (GSH) through GPx may be strongly limited by a low PLA2 activity. We address this issue using a moderately detailed kinetic model of mitochondrial lipid peroxidation in rat liver. The model was based on published data and was subjected to validation as reported in the references. It is analysed by computer simulation and sensitivity analysis. Results suggest that in rat liver mitochondria PHGPx is responsible for almost all phospholipid hydroperoxide reduction. Under physiological conditions, the estimated flux of phospholipid hydroperoxides reduction through PHGPx is about four orders of magnitude higher than the estimated hydrolysis flux through PLA2. On the other hand, virtually all hydrogen peroxide is reduced through GPx. Therefore, a functional complementarity between PHGPx and GPx is suggested. Because the results are qualitatively robust to changes of several orders of magnitude in PLA2 and PHGPx levels, the conclusions may not be limited to mitochondria.
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Affiliation(s)
- F Antunes
- Grupo de Bioquímica e Biologia Teóricas, Instituto de Investigação Científica Bento da Rocha Cabral, Lisboa, Portugal
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Kinkaid AR, Wilton DC. Enhanced hydrolysis of phosphatidylcholine by human group II non-pancreatic secreted phospholipase A2 as a result of interfacial activation by specific anions. Potential role of cholesterol sulphate. Biochem J 1995; 308 ( Pt 2):507-12. [PMID: 7772034 PMCID: PMC1136954 DOI: 10.1042/bj3080507] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The extracellular concentration of the Group II human non-pancreatic secreted phospholipase A2 (hnpsPLA2) is elevated in a variety of inflammatory disorders. This enzyme is remarkable because it demonstrates almost zero activity with egg phosphatidylcholine (PC) or synthetic dioleoyl-phosphatidylcholine (DOPC) as substrate, but expresses high activity with the anionic phospholipid dioleoyl-phosphatidylglycerol (DOPG), a feature shared with the Group II enzyme from rat liver. The presence of certain membrane-bound anions can enhance hydrolysis of PC by the mammalian secreted PLA2S. In this study the ability of various non-polar anions to stimulate DOPC hydrolysis by secreted PLA2S has been investigated. The naturally occurring membrane anion, cholesterol sulphate, was particularly effective in stimulating the hydrolysis of both DOPC and also 1-stearoyl-2-arachidonyl phosphatidylcholine by hnpsPLA2. Activation of DOPC hydrolysis was also achieved with dioleoyl-phosphatidylserine (DOPS); however, DOPS was less effective than cholesterol sulphate. In contrast, the dianion dioleoyl-phosphatidic acid, a known activator of pig pancreatic PLA2, failed to activate the human enzyme. It remains to be established whether cell plasma-membrane hydrolysis by extracellular hnpsPLA2 can be activated in vivo by the presence of suitable membrane anions such as cholesterol sulphate and thus promote an inflammatory response within the cell.
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Affiliation(s)
- A R Kinkaid
- Department of Biochemistry, University of Southampton, UK
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Abstract
Several mitochondrial functions decline with age. The contributing factors include, the intrinsic rate of proton leakage across the inner mitochondrial membrane (a correlate of oxidant formation), decreased membrane fluidity, and decreased levels and function of cardiolipin, which supports the function of many of the proteins of the inner mitochondrial membrane. Oxidants generated by mitochondria appear to be the major source of the oxidative lesions that accumulate with age. Evidence supports the suggestion that age-associated accumulation of mitochondrial deficits due to oxidative damage is likely to be a major contributor to cellular, tissue, and organismal aging.
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Affiliation(s)
- B N Ames
- Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA 94720-3202, USA
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Abstract
We argue for the critical role of oxidative damage in causing the mitochondrial dysfunction of aging. Oxidants generated by mitochondria appear to be the major source of the oxidative lesions that accumulate with age. Several mitochondrial functions decline with age. The contributing factors include the intrinsic rate of proton leakage across the inner mitochondrial membrane (a correlate of oxidant formation), decreased membrane fluidity, and decreased levels and function of cardiolipin, which supports the function of many of the proteins of the inner mitochondrial membrane. Acetyl-L-carnitine, a high-energy mitochondrial substrate, appears to reverse many age-associated deficits in cellular function, in part by increasing cellular ATP production. Such evidence supports the suggestion that age-associated accumulation of mitochondrial deficits due to oxidative damage is likely to be a major contributor to cellular, tissue, and organismal aging.
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Affiliation(s)
- M K Shigenaga
- Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720
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