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Gabrili JJM, Pidde G, Magnoli FC, Marques-Porto R, Villas-Boas IM, Squaiella-Baptistão CC, Silva-de-França F, Burgher F, Blomet J, Tambourgi DV. New Insights into Immunopathology Associated to Bothrops lanceolatus Snake Envenomation: Focus on PLA 2 Toxin. Int J Mol Sci 2023; 24:9931. [PMID: 37373079 DOI: 10.3390/ijms24129931] [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: 05/21/2023] [Revised: 06/04/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The systemic increase in inflammatory mediator levels can induce diverse pathological disorders, including potentially thrombus formation, which may be lethal. Among the clinical conditions in which the formation of thrombi dictates the patient's prognosis, envenomation by Bothrops lanceolatus should be emphasized, as it can evolve to stroke, myocardial infarction and pulmonary embolism. Despite their life-threatening potential, the immunopathological events and toxins involved in these reactions remain poorly explored. Therefore, in the present study, we examined the immunopathological events triggered by a PLA2 purified from B. lanceolatus venom, using an ex vivo human blood model of inflammation. Our results showed that the purified PLA2 from the venom of B. lanceolatus damages human erythrocytes in a dose dependent way. The cell injury was associated with a decrease in the levels of CD55 and CD59 complement regulators on the cell surface. Moreover, the generation of anaphylatoxins (C3a and C5a) and the soluble terminal complement complex (sTCC) indicates that human blood exposure to the toxin activates the complement system. Increased production of TNF-α, CXCL8, CCL2 and CCL5 followed complement activation. The venom PLA2 also triggered the generation of lipid mediators, as evidenced by the detected high levels of LTB4, PGE2 and TXB2. The scenario here observed of red blood cell damage, dysfunctions of the complement regulatory proteins, accompanied by an inflammatory mediator storm, suggests that B. lanceolatus venom PLA2 contributes to the thrombotic disorders present in the envenomed individuals.
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Affiliation(s)
- Joel J M Gabrili
- Immunochemistry Laboratory, Butantan Institute, São Paulo 05503-900, Brazil
| | - Giselle Pidde
- Immunochemistry Laboratory, Butantan Institute, São Paulo 05503-900, Brazil
| | | | - Rafael Marques-Porto
- Development and Innovation Laboratory, Butantan Institute, São Paulo 05503-900, Brazil
| | | | | | | | | | | | - Denise V Tambourgi
- Immunochemistry Laboratory, Butantan Institute, São Paulo 05503-900, Brazil
- Prevor Laboratory, 95760 Valmondois, France
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Jiang Z, Qu L, Song G, Liu J, Zhong G. The Potential Binding Interaction and Hydrolytic Mechanism of Carbaryl with the Novel Esterase PchA in Pseudomonas sp. PS21. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:2136-2145. [PMID: 35147028 DOI: 10.1021/acs.jafc.1c06465] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microbial bioremediation is a very potent and eco-friendly approach to alleviate pesticide pollution in agricultural ecosystems, and hydrolase is an effective element for contaminant degradation. In the present study, a novel Mn2+-dependent esterase, PchA, that efficiently hydrolyzes carbamate pesticides with aromatic structures was identified from Pseudomonas sp. PS21. The hydrolytic activity was confirmed to be related closely to the core catalytic domain, which consists of six residues. The crucial residues indirectly stabilized the position of carbaryl via chelating Mn2+ according to the binding model clarified by molecular simulations, and the additional hydrophobic interactions between carbaryl with several hydrophobic residues also stabilized the binding conformation. The residue Glu398, by serving as the general base, might activate a water molecule and facilitate PchA catalysis. This work offers valuable insights into the binding interaction and hydrolytic mechanism of carbaryl with the hydrolase PchA and will be crucial to designing strategies leading to the protein variants that are capable of degrading related contaminants.
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Affiliation(s)
- Zhiyan Jiang
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture and Rural Affairs, Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Liwen Qu
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture and Rural Affairs, Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Gaopeng Song
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Jie Liu
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture and Rural Affairs, Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Guohua Zhong
- Key Laboratory of Integrated Pest Management of Crop in South China, Ministry of Agriculture and Rural Affairs, Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
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Abdullah NAH, Rusmili MRA, Zainal Abidin SA, Shaikh MF, Hodgson WC, Othman I. Isolation and Characterization of A2-EPTX-Nsm1a, a Secretory Phospholipase A 2 from Malaysian Spitting Cobra ( Naja sumatrana) Venom. Toxins (Basel) 2021; 13:toxins13120859. [PMID: 34941697 PMCID: PMC8709200 DOI: 10.3390/toxins13120859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/22/2021] [Accepted: 11/27/2021] [Indexed: 02/07/2023] Open
Abstract
Phospholipase A2 (PLA2) toxins are one of the main toxin families found in snake venom. PLA2 toxins are associated with various detrimental effects, including neurotoxicity, myotoxicity, hemostatic disturbances, nephrotoxicity, edema, and inflammation. Although Naja sumatrana venom contains substantial quantities of PLA2 components, there is limited information on the function and activities of PLA2 toxins from the venom. In this study, a secretory PLA2 from the venom of Malaysian N. sumatrana, subsequently named A2-EPTX-Nsm1a, was isolated, purified, and characterized. A2-EPTX-Nsm1a was purified using a mass spectrometry-guided approach and multiple chromatography steps. Based on LC-MSMS, A2-EPTX-Nsm1a was found to show high sequence similarity with PLA2 from venoms of other Naja species. The PLA2 activity of A2-EPTX-Nsm1 was inhibited by 4-BPB and EDTA. A2-EPTX-Nsm1a was significantly less cytotoxic in a neuroblastoma cell line (SH-SY5Y) compared to crude venom and did not show a concentration-dependent cytotoxic activity. To our knowledge, this is the first study that characterizes and investigates the cytotoxicity of an Asp49 PLA2 isolated from Malaysian N. sumatrana venom in a human neuroblastoma cell line.
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Affiliation(s)
- Nur Atiqah Haizum Abdullah
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia; (S.A.Z.A.); (M.F.S.)
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia
- Correspondence: or (N.A.H.A.); (I.O.)
| | - Muhamad Rusdi Ahmad Rusmili
- Kulliyyah of Pharmacy, Kuantan Campus, International Islamic University Malaysia, Bandar Indera Mahkota, Kuantan 25200, Malaysia;
| | - Syafiq Asnawi Zainal Abidin
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia; (S.A.Z.A.); (M.F.S.)
| | - Mohd Farooq Shaikh
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia; (S.A.Z.A.); (M.F.S.)
| | - Wayne C. Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia;
| | - Iekhsan Othman
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia; (S.A.Z.A.); (M.F.S.)
- Correspondence: or (N.A.H.A.); (I.O.)
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Huancahuire-Vega S, Corrêa DHA, Hollanda LM, Lancellotti M, Ramos CHI, Ponce-Soto LA, Marangoni S. Chemical modifications of PhTX-I myotoxin from Porthidium hyoprora snake venom: effects on structural, enzymatic, and pharmacological properties. BIOMED RESEARCH INTERNATIONAL 2012; 2013:103494. [PMID: 23484072 PMCID: PMC3591178 DOI: 10.1155/2013/103494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/31/2012] [Indexed: 12/03/2022]
Abstract
We recently described the isolation of a basic PLA2 (PhTX-I) from Porthidium hyoprora snake venom. This toxin exhibits high catalytic activity, induces in vivo myotoxicity, moderates footpad edema, and causes in vitro neuromuscular blockade. Here, we describe the chemical modifications of specific amino acid residues (His, Tyr, Lys, and Trp), performed in PhTX-I, to study their effects on the structural, enzymatic, and pharmacological properties of this myotoxin. After chemical treatment, a single His, 4 Tyr, 7 Lys, and one Trp residues were modified. The secondary structure of the protein remained unchanged as measured by circular dichroism; however other results indicated the critical role played by Lys and Tyr residues in myotoxic, neurotoxic activities and mainly in the cytotoxicity displayed by PhTX-I. His residue and therefore catalytic activity of PhTX-I are relevant for edematogenic, neurotoxic, and myotoxic effects, but not for its cytotoxic activity. This dissociation observed between enzymatic activity and some pharmacological effects suggests that other molecular regions distinct from the catalytic site may also play a role in the toxic activities exerted by this myotoxin. Our observations supported the hypothesis that both the catalytic sites as the hypothetical pharmacological sites are relevant to the pharmacological profile of PhTX-I.
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Affiliation(s)
- Salomón Huancahuire-Vega
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Daniel H. A. Corrêa
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Luciana M. Hollanda
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Marcelo Lancellotti
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Carlos H. I. Ramos
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
- National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ, Brazil
| | - Luis Alberto Ponce-Soto
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Sergio Marangoni
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
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Zhao ZX, Wang XS, Qin X, Chen Q, Anzai JI. Enzyme microcapsules with substrate selective permeability constructed via layer-by-layer polyelectrolyte self-assembly. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2011.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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8
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Tzeng MC. Interaction of Presynaptically Toxic Phospholipases A2with Membrane Receptors and Other Binding Sites. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569549309084185] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Klingler M, Demmelmair H, Larque E, Koletzko B. Analysis of FA contents in individual lipid fractions from human placental tissue. Lipids 2003; 38:561-6. [PMID: 12880113 DOI: 10.1007/s11745-003-1496-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Data on FA contents in the human placenta are limited. Different methods have been used for the FA analysis, and only percentage results have been presented. We developed and evaluated a method for the determination of FA concentrations in placental tissue. Lipids were extracted from placental tissue with a chloroform/methanol mixture; and phospholipids (PL), nonesterified FA (NEFA), TG, and cholesterol esters (CE) were isolated by TLC. Individual lipid fractions were derivatized with methanolic hydrochloric acid, and the FAME were quantified by GC with FID. The CV of intra-assay (n = 8) of absolute concentrations were evaluated for FA showing a tissue content > 0.01 mg/g. CV ranges were 4.6-11.0% for PL, 6.4-9.3% for NEFA, 6.1-8.9% for TG, and 11.4-16.3% for CE. The relative FA composition across a term placenta indicated no differences between samples of central and peripheral locations of maternal and fetal site (CV 0.5-9.9%), whereas the absolute FA concentrations were only reproducible in the PL fraction (CV 7.0-12.8%). The method shows a reasonably high precision that is well suited for physiological and nutritional studies.
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Affiliation(s)
- M Klingler
- Division of Metabolism and Nutrition, Kinderklinik and Kinderpoliklinik, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University of Munich, D-80337, Munich, Germany
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Nagababu E, Lakshmaiah N. Inhibition of xanthine oxidase-xanthine-iron mediated lipid peroxidation by eugenol in liposomes. Mol Cell Biochem 1997; 166:65-71. [PMID: 9046022 DOI: 10.1023/a:1006878315029] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effect of eugenol on xanthine oxidase (XO) xanthine(X)-Fe+3-ADP mediated lipid peroxidation was studied in liver microsomal lipid liposomes. Eugenol inhibited the lipid peroxidation in a dose dependent manner as assessed by formation of thiobarbituric acid reactive substances. When tested for its effect on XO activity per se, (by measuring uric acid formation) eugenol inhibited the enzyme to an extent of 85% at 10 microm concentration and hence formation of O2.- also. However, the concentration of eugenol required for XO inhibition was more in presence of metal chelators such as EDTA, EGTA and DETAPAC, but not in presence of deferoxamine, ADP and citrate. The antiperoxidative effect of eugenol was about 35 times more and inhibition of XO was about 5 times higher as compared to the effect of allopurinol. Eugenol did not scavenge O2.- generated by phenazine methosulfate and NAD but inhibited propagation of peroxidation catalyzed by Fe2+ EDTA and lipid hydroperoxide containing liposomes. Eugenol inhibits XO-X-Fe+3 ADP mediated peroxidation by inhibiting the XO activity per se in addition to quenching various radical species.
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Affiliation(s)
- E Nagababu
- Department of Biochemistry, National Institute of Nutrition, Indian Council of Medical Research, Jamai Osmania, India
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Shina R, Crain RC, Rosenberg P, Condrea E. Exposure of phosphatidylcholine and phosphatidylinositol in plasma membranes from rat brain synaptosomes treated with phospholipase A2 toxins (beta-bungarotoxin, notexin) and enzymes (Naja nigricollis, Naja naja atra). Toxicon 1994; 32:675-85. [PMID: 7940575 DOI: 10.1016/0041-0101(94)90337-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Phospholipase A2 (PLA2) toxins act presynaptically to block acetylcholine release and are much more potent and specific in their actions than PLA2 enzymes even though they have lower enzymatic activity. Since their mechanism of action is not completely understood, it was of interest to examine the toxins' effects on phospholipid asymmetry as changes in asymmetry are associated with changes in membrane functioning. Rat brain synaptosomes were treated with the PLA2 toxins beta-bungarotoxin (beta-BuTx) and notexin and with the PLA2 enzymes Naja nigricollis and Naja naja atra under relatively non-disruptive conditions as judged by leakage of lactate dehydrogenase (LDH) and levels of phospholipid hydrolysis. The exposure of phosphatidylcholine (PC) and phosphatidylinositol (PI) on the synaptosomal surface was investigated by means of a specific PC-exchange protein (PCEP) and a PI-specific phospholipase C (PI-PLC), respectively. Treatment of the synaptosomes with N. nigricollis PLA2, beta-BuTx and notexin did not affect the availability of PC to exchange by PCEP, but significantly increased the exposure of PI to hydrolysis by PI-PLC. In contrast, N. n. atra PLA2 slightly decreased the exposure of PC and did not affect that of PI. The differences between N. n. atra PLA2, on the one hand, and N. nigricollis PLA2, beta-BuTx and notexin, on the other hand, parallel differences in their pharmacological activities. Our earlier studies showed that PLA2 enzymes, and possibly PLA2 toxins, have a pharmacological site separate from the enzymatic site. Since in the present study the effect on PI was abolished by EDTA, the presence of an enzymatic site in addition to the pharmacological site may be required or alternatively divalent cations may be required for the effects on PI asymmetry independent of the inhibition of PLA2 by EDTA.
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Affiliation(s)
- R Shina
- Basil and Gerald Felsenstein Medical Research Center, Petah Tikva, Israel
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Noponen M, Sanfilipo M, Samanich K, Ryer H, Ko G, Angrist B, Wolkin A, Duncan E, Rotrosen J. Elevated PLA2 activity in schizophrenics and other psychiatric patients. Biol Psychiatry 1993; 34:641-9. [PMID: 8292693 DOI: 10.1016/0006-3223(93)90157-9] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We measured serum phospholipase A2 (PLA2) activity in 39 schizophrenics, 26 psychiatric controls, and 26 normal controls using a radioenzymatic assay with phosphatidylcholine as precursor. Serum PLA2 activity was significantly higher in schizophrenics (p = 0.002) and other psychiatric (including substance abusing) patients (p = 0.032) than in normal controls. Enzyme activity did not differ between the schizophrenic patients and psychiatric controls. Fifty-one percent of the schizophrenics and 46% of psychiatric controls had PLA2 values above the highest value for normal controls. In the psychiatric control group higher than normal PLA2 activities were observed in all diagnostic categories, including major depression, bipolar disorder, posttraumatic stress disorder (PTSD), and substance abuse. In the context of others' findings of increased circulating PLA2 in infectious and inflammatory conditions, these increases must be viewed as disease nonspecific. The significance of these changes and their relationship to other acute-phase protein changes needs to be clarified in future research.
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Affiliation(s)
- M Noponen
- Department of Veterans Affairs Medical Center New York, NY 10010
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Yokote K, Morisaki N, Zenibayashi M, Ueda S, Kanzaki T, Saito Y, Yoshida S. The phospholipase-A2 reaction leads to increased monocyte adhesion of endothelial cells via the expression of adhesion molecules. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 217:723-9. [PMID: 8223614 DOI: 10.1111/j.1432-1033.1993.tb18298.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mononuclear cell invasion into the vascular-vessel wall is a very important initial step in the development of atherosclerotic lesions. Hypercholesterolemia leads to a marked adhesion of circulating blood monocytes to arterial endothelial cells in vivo, and minimally oxidized low-density lipoprotein enhances monocyte adhesion to endothelial cells in vitro. The activation of phospholipase A2 (PLA2) is also important in the oxidation of low-density lipoprotein by endothelial cells. In this study, we investigated the role of PLA2 activation in the adhesion of a leukemic monocyte cell line (THP-1 cells) to endothelial cells in vitro using an adhesion assay and a cell-ELISA technique. The treatment of human umbilical-cord-vein endothelial cells with PLA2 stimulators such as interleukin-1 beta, tumor necrosis factor and lipopolysaccharide all increased the adhesion of THP-1 cells to endothelial cells. Exogenous PLA2 also increased the adhesion of these cell types. The increased adhesion induced by these PLA2 stimulators, as well as PLA2 itself, was reversed by various inhibitors of the PLA2 reaction. A product of the PLA2 reaction, lysophosphatidylcholine, also increased cell adhesion. A cell-ELISA technique showed the enhanced expression of vascular-cell-adhesion-molecule 1 and intercellular-adhesion-molecule 1 to endothelial cells after treatment with PLA2 stimulators, PLA2 or lysophosphatidylcholine. These results suggest that the PLA2 reaction enhances monocyte adhesion to endothelial cells through the expression of cellular adhesion molecules.
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Affiliation(s)
- K Yokote
- First Department of Internal Medicine, School of Medicine, Chiba University, Japan
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Shina R, Crain RC, Rosenberg P, Condrea E. The asymmetric distribution of phosphatidylcholine in rat brain synaptic plasma membranes. Neurochem Int 1993; 22:189-95. [PMID: 8439772 PMCID: PMC7135640 DOI: 10.1016/0197-0186(93)90012-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The distribution of phosphatidylcholine between inner and outer monolayers of rat brain synaptic plasma membrane was investigated by means of a phosphatidylcholine specific exchange protein. About 70% of the total membranal phosphatidylcholine was in the outer leaflet, 33% of which was exposed and readily exchanged in intact synaptosomes while the remainder was exchangeable following osmotic shock. Permeabilization of the synaptic plasma membranes by overnight incubation in buffer or by saponin (< 0.08%) exposed an additional 30% of phosphatidylcholine to exchange, presumably from the inner cytoplasmic leaflet. Phosphatidylcholine is therefore asymmetrically distributed in the synaptosomal plasma membrane, as it is in other plasma membranes.
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Affiliation(s)
- R Shina
- Basil and Gerald Felsenstein Medical Research Center, Rogoff-Wellcome Medical Research Institute, Sackler School of Medicine, Tel Aviv University, Beilinson Medical Center, Petah Tikva, Israel
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Shina R, Rosenberg P, Condrea E. An EDTA.Ca2+ complex inhibits the enzymatic activity but not the lethality of beta-bungarotoxin. Toxicon 1992; 30:1501-4. [PMID: 1485347 DOI: 10.1016/0041-0101(92)90529-e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An EDTA.Ca2+ complex inhibits the phospholipase A2 activity of the presynaptic neurotoxin beta-bungarotoxin without affecting its lethal potency. The EDTA.Ca2+ complex induces a conformational change in the enzymatic active site region of beta-BuTx, as indicated by the suppression of the 340 nm tryptophan fluorescence peak. Modification of the enzymatic site without loss of toxicity supports the presence of separate loci for the two activities.
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Affiliation(s)
- R Shina
- Felsenstein Medical Research Center, Petah Tikva, Israel
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