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Pinto AV, Ferreira P, Cunha AV, Havenith RWA, Magalhães AL, Ramos MJ, Fernandes PA. Revisiting the reaction pathways for phospholipid hydrolysis catalyzed by phospholipase A2 with QM/MM methods. Chem Sci 2024; 15:9793-9805. [PMID: 38939148 PMCID: PMC11206408 DOI: 10.1039/d4sc02315c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 05/17/2024] [Indexed: 06/29/2024] Open
Abstract
Secreted phospholipase A2 (sPLA2) is a Ca2+-dependent, widely distributed enzyme superfamily in almost all mammalian tissues and bacteria. It is also a critical component of the venom of nearly all snakes, as well as many invertebrate species. In non-venomous contexts, sPLA2 assumes significance in cellular signaling pathways by binding cell membranes and catalyzing ester bond hydrolysis at the sn-2 position of phospholipids. Elevated levels of GIIA sPLA2 have been detected in the synovial fluid of arthritis patients, where it exhibits a pro-inflammatory function. Consequently, identifying sPLA2 inhibitors holds promise for creating highly effective pharmaceutical treatments. Beyond arthritis, the similarities among GIIA sPLA2s offer an opportunity for developing treatments against snakebite envenoming, the deadliest neglected tropical disease. Despite decades of study, the details of PLA2 membrane-binding, substrate-binding, and reaction mechanism remain elusive, demanding a comprehensive understanding of the sPLA2 catalytic mechanism. This study explores two reaction mechanism hypotheses, involving one or two water molecules, and distinct roles for the Ca2+ cofactor. Our research focuses on the human synovial sPLA2 enzyme bound to lipid bilayers of varying phospholipid compositions, and employing adiabatic QM/MM and QM/MM MD umbrella sampling methods to energetically and geometrically characterize the structures found along both reaction pathways. Our studies demonstrate the higher frequency of productive conformations within the single-water pathway, also revealing a lower free energy barrier for hydrolyzing POPC. Furthermore, we observe that the TS of this concerted one-step reaction closely resembles transition state geometries observed in X-ray crystallography complexes featuring high-affinity transition state analogue inhibitors.
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Affiliation(s)
- Alexandre V Pinto
- LAQV/Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre, s/n 4169-007 Porto Portugal
| | - Pedro Ferreira
- LAQV/Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre, s/n 4169-007 Porto Portugal
| | - Ana V Cunha
- MolSpec, Departement Chemie, Universiteit Antwerpen Groenenborgerlaan 171 2020 Antwerpen Belgium
| | - Remco W A Havenith
- Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen Nijenborgh 4 9747 AG Groningen Netherlands
- The Netherlands and Ghent Quantum Chemistry Group, Department of Chemistry, Ghent University Krijgslaan 281 (S3) B-9000 Gent Belgium
| | - Alexandre L Magalhães
- LAQV/Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre, s/n 4169-007 Porto Portugal
| | - Maria J Ramos
- LAQV/Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre, s/n 4169-007 Porto Portugal
| | - Pedro A Fernandes
- LAQV/Requimte, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre, s/n 4169-007 Porto Portugal
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Antimalarial Activity of Human Group IIA Secreted Phospholipase A 2 in Relation to Enzymatic Hydrolysis of Oxidized Lipoproteins. Infect Immun 2019; 87:IAI.00556-19. [PMID: 31405958 DOI: 10.1128/iai.00556-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 08/07/2019] [Indexed: 12/12/2022] Open
Abstract
The level of human group IIA secreted phospholipase A2 (hGIIA sPLA2) is increased in the plasma of malaria patients, but its role is unknown. In parasite culture with normal plasma, hGIIA is inactive against Plasmodium falciparum, contrasting with hGIIF, hGV, and hGX sPLA2s, which readily hydrolyze plasma lipoproteins, release nonesterified fatty acids (NEFAs), and inhibit parasite growth. Here, we revisited the anti-Plasmodium activity of hGIIA under conditions closer to those of malaria physiopathology where lipoproteins are oxidized. In parasite culture containing oxidized lipoproteins, hGIIA sPLA2 was inhibitory, with a 50% inhibitory concentration value of 150.0 ± 40.8 nM, in accordance with its capacity to release NEFAs from oxidized particles. With oxidized lipoproteins, hGIIF, hGV, and hGX sPLA2s were also more potent, by 4.6-, 2.1-, and 1.9-fold, respectively. Using specific immunoassays, we found that hGIIA sPLA2 is increased in plasma from 41 patients with malaria over levels for healthy donors (median [interquartile range], 1.6 [0.7 to 3.4] nM versus 0.0 [0.0 to 0.1] nM, respectively; P < 0.0001). Other sPLA2s were not detected. Malaria plasma, but not normal plasma, contains oxidized lipoproteins and was inhibitory to P. falciparum when spiked with hGIIA sPLA2 Injection of recombinant hGIIA into mice infected with P. chabaudi reduced the peak of parasitemia, and this was effective only when the level of plasma peroxidation was increased during infection. In conclusion, we propose that malaria-induced oxidation of lipoproteins converts these into a preferential substrate for hGIIA sPLA2, promoting its parasite-killing effect. This mechanism may contribute to host defense against P. falciparum in malaria where high levels of hGIIA are observed.
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Massimino ML, Simonato M, Spolaore B, Franchin C, Arrigoni G, Marin O, Monturiol-Gross L, Fernández J, Lomonte B, Tonello F. Cell surface nucleolin interacts with and internalizes Bothrops asper Lys49 phospholipase A 2 and mediates its toxic activity. Sci Rep 2018; 8:10619. [PMID: 30006575 PMCID: PMC6045611 DOI: 10.1038/s41598-018-28846-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/20/2018] [Indexed: 01/01/2023] Open
Abstract
Phospholipases A2 are a major component of snake venoms. Some of them cause severe muscle necrosis through an unknown mechanism. Phospholipid hydrolysis is a possible explanation of their toxic action, but catalytic and toxic properties of PLA2s are not directly connected. In addition, viperid venoms contain PLA2-like proteins, which are very toxic even if they lack catalytic activity due to a critical mutation in position 49. In this work, the PLA2-like Bothrops asper myotoxin-II, conjugated with the fluorophore TAMRA, was found to be internalized in mouse myotubes, and in RAW264.7 cells. Through experiments of protein fishing and mass spectrometry analysis, using biotinylated Mt-II as bait, we found fifteen proteins interacting with the toxin and among them nucleolin, a nucleolar protein present also on cell surface. By means of confocal microscopy, Mt-II and nucleolin were shown to colocalise, at 4 °C, on cell membrane where they form Congo-red sensitive assemblies, while at 37 °C, 20 minutes after the intoxication, they colocalise in intracellular spots going from plasmatic membrane to paranuclear and nuclear area. Finally, nucleolin antagonists were found to inhibit the Mt-II internalization and toxic activity and were used to identify the nucleolin regions involved in the interaction with the toxin.
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Affiliation(s)
| | - Morena Simonato
- Istituto di Neuroscienze, CNR, Via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Barbara Spolaore
- Dipartimento di Scienze del Farmaco, Università di Padova, Via F. Marzolo, 5, 35131, Padova, Italy
| | - Cinzia Franchin
- Dipartimento di Scienze Biomediche, Università di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy
- Centro di Proteomica, Università di Padova e Azienda Ospedaliera di Padova, Via G. Orus 2/B, 35129, Padova, Italy
| | - Giorgio Arrigoni
- Dipartimento di Scienze Biomediche, Università di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy
- Centro di Proteomica, Università di Padova e Azienda Ospedaliera di Padova, Via G. Orus 2/B, 35129, Padova, Italy
| | - Oriano Marin
- Dipartimento di Scienze Biomediche, Università di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Laura Monturiol-Gross
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, 11501, San José, Costa Rica
| | - Julián Fernández
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, 11501, San José, Costa Rica
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, 11501, San José, Costa Rica
| | - Fiorella Tonello
- Istituto di Neuroscienze, CNR, Via Ugo Bassi 58/B, 35131, Padova, Italy.
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Modulated mechanism of phosphatidylserine on the catalytic activity of Naja naja atra phospholipase A2 and Notechis scutatus scutatus notexin. Toxicon 2014; 92:113-22. [PMID: 25449100 DOI: 10.1016/j.toxicon.2014.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/01/2014] [Accepted: 10/09/2014] [Indexed: 11/24/2022]
Abstract
Phosphatidylserine (PS) externalization is a hallmark for apoptotic death of cells. Previous studies showed that Naja naja atra phospholipase A2 (NnaPLA2) and Notechis scutatus scutatus notexin induced apoptosis of human cancer cells. However, NnaPLA2 and notexin did not markedly disrupt the integrity of cellular membrane as evidenced by membrane permeability of propidium iodide. These findings reflected that the ability of NnaPLA2 and notexin to hydrolyze membrane phospholipids may be affected by PS externalization. To address that question, this study investigated the membrane-interacted mode and catalytic activity of NnaPLA2 and notexin toward outer leaflet (phosphatidylcholine/sphingomyelin/cholesterol, PC/SM/Chol) and inner leaflet (phosphatidylserine/phosphatidylethanolamine/cholesterol, PS/PE/Chol) of plasma membrane-mimicking vesicles. PS incorporation promoted enzymatic activity of NnaPLA2 and notexin on PC and PC/SM vesicles, but suppressed NnaPLA2 and notexin activity on PC/SM/Chol and PE/Chol vesicles. PS incorporation increased the membrane fluidity of PC vesicles but reduced membrane fluidity of PC/SM, PC/SM/Chol and PE/Chol vesicles. PS increased the phospholipid order of all the tested vesicles. Moreover, PS incorporation did not greatly alter the binding affinity of notexin and NnaPLA2 with phospholipid vesicles. Acrylamide quenching studies and trinitrophenylation of Lys residues revealed that membrane-bound mode of notexin and NnaPLA2 varied with the targeted membrane compositions. The fine structure of catalytic site in NnaPLA2 and notexin in all the tested vesicles showed different changes. Collectively, the present data suggest that membrane-inserted PS modulates PLA2 interfacial activity via its effects on membrane structure and membrane-bound mode of NnaPLA2 and notexin, and membrane compositions determine the effect of PS on PLA2 activity.
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Gibbons E, Murri M, Grabner A, Moss E, Campbell L, Nelson J, Judd AM, Bell JD. Ionomycin causes susceptibility to phospholipase A2 while temperature-induced increases in membrane fluidity fail: possible involvement of actin fragmentation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2607-14. [PMID: 24998360 DOI: 10.1016/j.bbamem.2014.05.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/10/2014] [Accepted: 05/30/2014] [Indexed: 12/16/2022]
Abstract
A diminution in the order of membrane lipids, which occurs during apoptosis, has been shown to correlate with increased membrane susceptibility to hydrolysis by secretory phospholipase A2. Studies with artificial membranes, however, have demonstrated that the relationship between membrane order and hydrolysis is more complex than suggested thus far by cell studies. To better resolve this relationship, this study focused on comparisons between increasing temperature and calcium ionophore as means of decreasing membrane order in S49 cells. Although these two treatments caused comparable changes in apparent membrane order as detected by steady-state fluorescence measurements, only ionophore treatment enhanced phospholipase activity. Experiments with exogenously-added phosphatidylserine indicated that the difference was not due to the presence of that anionic phospholipid in the outer membrane leaflet. Instead, analysis of the equilibration kinetics of various cationic membrane probes revealed that the difference could relate to the spacing of membrane lipids. Specifically, ionophore treatment increased that spacing while temperature only affected overall membrane order and fluidity. To consider the possibility that the distinction with ionophore might relate to the actin cytoskeleton, cells were stained with phalloidin and imaged via confocal microscopy. Ionophore caused disruption of actin fibers while increased temperature did not. This apparent connection between membrane hydrolysis and the cytoskeleton was further corroborated by examining the relationship among these events during apoptosis stimulated by thapsigargin.
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Affiliation(s)
- Elizabeth Gibbons
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Michael Murri
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Amy Grabner
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Eric Moss
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Lauryl Campbell
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Jennifer Nelson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - Allan M Judd
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
| | - John D Bell
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.
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Membrane properties involved in calcium-stimulated microparticle release from the plasma membranes of S49 lymphoma cells. ScientificWorldJournal 2014; 2014:537192. [PMID: 24578641 PMCID: PMC3918691 DOI: 10.1155/2014/537192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/04/2013] [Indexed: 11/17/2022] Open
Abstract
This study answered the question of whether biophysical mechanisms for microparticle shedding discovered in platelets and erythrocytes also apply to nucleated cells: cytoskeletal disruption, potassium efflux, transbilayer phospholipid migration, and membrane disordering. The calcium ionophore, ionomycin, disrupted the actin cytoskeleton of S49 lymphoma cells and produced rapid release of microparticles. This release was significantly inhibited by interventions that impaired calcium-activated potassium current. Microparticle release was also greatly reduced in a lymphocyte cell line deficient in the expression of scramblase, the enzyme responsible for calcium-stimulated dismantling of the normal phospholipid transbilayer asymmetry. Rescue of the scrambling function at high ionophore concentration also resulted in enhanced particle shedding. The effect of membrane physical properties was addressed by varying the experimental temperature (32–42°C). A significant positive trend in the rate of microparticle release as a function of temperature was observed. Fluorescence experiments with trimethylammonium diphenylhexatriene and Patman revealed significant decrease in the level of apparent membrane order along that temperature range. These results demonstrated that biophysical mechanisms involved in microparticle release from platelets and erythrocytes apply also to lymphocytes.
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Nyegaard S, Novakovic VA, Rasmussen JT, Gilbert GE. Lactadherin inhibits secretory phospholipase A2 activity on pre-apoptotic leukemia cells. PLoS One 2013; 8:e77143. [PMID: 24194865 PMCID: PMC3806724 DOI: 10.1371/journal.pone.0077143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/21/2013] [Indexed: 01/09/2023] Open
Abstract
Secretory phospholipase A2 (sPLA2) is a critical component of insect and snake venoms and is secreted by mammalian leukocytes during inflammation. Elevated secretory PLA2 concentrations are associated with autoimmune diseases and septic shock. Many sPLA2’s do not bind to plasma membranes of quiescent cells but bind and digest phospholipids on the membranes of stimulated or apoptotic cells. The capacity of these phospholipases to digest membranes of stimulated or apoptotic cells correlates to the exposure of phosphatidylserine. In the present study, the ability of the phosphatidyl-L-serine-binding protein, lactadherin to inhibit phospholipase enzyme activity has been assessed. Inhibition of human secretory phospholipase A2-V on phospholipid vesicles exceeded 90%, whereas inhibition of Naja mossambica sPLA2 plateaued at 50–60%. Lactadherin inhibited 45% of activity of Naja mossambica sPLA2 and >70% of human secretory phospholipase A2-V on the membranes of human NB4 leukemia cells treated with calcium ionophore A23187. The data indicate that lactadherin may decrease inflammation by inhibiting sPLA2.
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Affiliation(s)
- Steffen Nyegaard
- Department of Molecular Biology, Aarhus University, Aarhus C, Denmark
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Valerie A. Novakovic
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jan T. Rasmussen
- Department of Molecular Biology, Aarhus University, Aarhus C, Denmark
- * E-mail:
| | - Gary E. Gilbert
- Departments of Medicine, Veterans Administration Boston Healthcare System, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
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Synergistic effects of secretory phospholipase A2 from the venom of Agkistrodon piscivorus piscivorus with cancer chemotherapeutic agents. BIOMED RESEARCH INTERNATIONAL 2012; 2013:565287. [PMID: 23509743 PMCID: PMC3591165 DOI: 10.1155/2013/565287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 08/15/2012] [Indexed: 02/08/2023]
Abstract
Healthy cells typically resist hydrolysis catalyzed by snake venom secretory phospholipase A2. However, during various forms of programmed cell death, they become vulnerable to attack by the enzyme. This observation raises the question of whether the specificity of the enzyme for dying cells could be used as a strategy to eliminate tumor cells that have been intoxicated but not directly killed by chemotherapeutic agents. This idea was tested with S49 lymphoma cells and a broad range of antineoplastic drugs: methotrexate, daunorubicin, actinomycin D, and paclitaxel. In each case, a substantial population of treated cells was still alive yet vulnerable to attack by the enzyme. Induction of cell death by these agents also perturbed the biophysical properties of the membrane as detected by merocyanine 540 and trimethylammonium-diphenylhexatriene. These results suggest that exposure of lymphoma cells to these drugs universally causes changes to the cell membrane that render it susceptible to enzymatic attack. The data also argue that the snake venom enzyme is not only capable of clearing cell corpses but can aid in the demise of tumor cells that have initiated but not yet completed the death process.
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