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Murphy K, Tasoulis T, Dunstan N, Isbister GK. Anticoagulant activity in Australasian elapid snake venoms and neutralisation with antivenom and varespladib. Toxicon 2024; 247:107836. [PMID: 38945217 DOI: 10.1016/j.toxicon.2024.107836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/04/2024] [Accepted: 06/25/2024] [Indexed: 07/02/2024]
Abstract
The venoms of Australasian elapid snakes are known to possess coagulant activity, including some with strong procoagulant activity and others with anticoagulant activity, although the latter are less well known. This study investigates the anticoagulant activity of Australasian elapid snake venoms, and whether this activity is neutralised by commercial snake antivenom and varespladib (PLA2 inhibiting agent). Clotting assays were completed for 34 species of Australasian elapids. Antivenom neutralisation assays with tiger snake antivenom (TSAV) were performed on five species to determine if there was cross-neutralisation. Varespladib neutralisation assays were also completed for the same five species. All Pseudechis species venoms had anticoagulant activity, except P. porphyriacus, which was procoagulant. Pseudechis species venoms had similar anticoagulant potency ranging from the most potent P. colletti venom to the least potent P. butleri venom. The three Austrelaps (copperhead) species venoms were the next most potent anticoagulants. Six further snakes, Elapognathus coronatus, Acanthophis pyrrhus, A. antarcticus, Suta suta, Denisonia devisi and D. maculata, had weaker anticoagulant activity, except for D. maculata which had similar anticoagulant activity to Pseudechis species. Tiger Snake Antivenom (1200mU/mL) neutralised the anticoagulant effect of P. australis for concentrations up to 1 mg/mL. TSAV (1200mU/mL) also neutralised P. colletti, D. maculata, A. superbus and A. pyrrhus venoms at their EC50, demonstrating cross neutralisation. Varespladib neutralised the anticoagulant effect of P. australis venom at 5 μM and for venoms of P. colletti, D. maculata, A. superbus and A. pyrrhus. We found anticoagulant activity to be present in six genera of Australasian snakes at low concentrations, which can be completely neutralised by both antivenom and varespladib. Anticoagulant activity in Australian elapid venoms was associated with species possessing high PLA2 activity without procoagulant snake venom serine proteases.
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Affiliation(s)
- Kate Murphy
- Clinical Toxicology Research Group, University of Newcastle, New South Wales, Australia
| | - Theo Tasoulis
- Clinical Toxicology Research Group, University of Newcastle, New South Wales, Australia
| | | | - Geoffrey K Isbister
- Clinical Toxicology Research Group, University of Newcastle, New South Wales, Australia; Department of Clinical Toxicology, Calvary Mater Newcastle, New South Wales, Australia.
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Damm M, Avella I, Merzara R, Lucchini N, Buldain J, Corga F, Bouazza A, Fahd S, Süssmuth RD, Martínez-Freiría F. Venom variation among the three subspecies of the North African mountain viper Vipera monticola Saint Girons 1953. Biochimie 2024:S0300-9084(24)00167-6. [PMID: 39029575 DOI: 10.1016/j.biochi.2024.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 07/16/2024] [Indexed: 07/21/2024]
Abstract
The North African mountain viper (Vipera monticola) is a medically relevant venomous snake distributed in Morocco, Algeria, and Tunisia. Three subspecies of V. monticola, exhibiting differences in morphotypes and dietary regimes, are currently recognised: V. m. monticola, V. m. atlantica, and V. m. saintgironsi. Through the application of snake venomics, we analysed the venoms of specimens of Moroccan origin belonging to each of the three subspecies. Snake venom metalloproteinases (svMP), snake venom serine proteases (svSP), C-type lectin and C-type lectin-related proteins (CTL), and phospholipases A2 (PLA2) were predominant, with PLA2 being the most abundant toxin family overall. Disintegrins (DI) and cysteine-rich secretory proteins (CRISP) were exclusive to V. m. monticola and V. m. atlantica, while l-amino-acid oxidases (LAAO) were only found in V. m. saintgironsi. The differences detected in the venom profiles, as well as in presence/absence and relative abundances of toxin families, indicate the occurrence of intraspecific venom variation within V. monticola. The identified patterns of venom similarity between subspecies seem to align more with their phylogenetic relationships than with the reported differences in their feeding habits.
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Affiliation(s)
- Maik Damm
- Institute for Insect Biotechnology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392, Gießen, Germany; LOEWE-Centre for Translational Biodiversity Genomics, Senckenberganlage 25, 60325, Frankfurt Am Main, Germany; Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany; Animal Venomics Lab, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, 35392 Gießen, Germany.
| | - Ignazio Avella
- Institute for Insect Biotechnology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392, Gießen, Germany; LOEWE-Centre for Translational Biodiversity Genomics, Senckenberganlage 25, 60325, Frankfurt Am Main, Germany; Animal Venomics Lab, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, 35392 Gießen, Germany
| | - Reema Merzara
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Nahla Lucchini
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Jon Buldain
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Frederico Corga
- Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Abdellah Bouazza
- Equipe de recherche Exploration, Gestion des Ressources naturelles et Environnementales, Polydisciplinary Faculty of Taroudant, Ibn Zohr University, Morocco
| | - Soumia Fahd
- Laboratoire Ecologie, Systématique, Conservation de la Biodiversité, LESCB URL-CNRST N°18, FS, Abdelmalek Essaadi University, Tétouan, Morocco
| | - Roderich D Süssmuth
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
| | - Fernando Martínez-Freiría
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal.
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Coimbra FCP, Sanchez EE, Lomonte B, Gutiérrez JM, Calvete JJ, Fry BG. Blood Lines: Intraspecific and Interspecific Variations in Anticoagulant Actions of Agkistrodon Viperid Venoms. Toxins (Basel) 2024; 16:291. [PMID: 39057931 PMCID: PMC11281148 DOI: 10.3390/toxins16070291] [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: 05/28/2024] [Revised: 06/23/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
This study investigated the intraspecific and interspecific variability in the venom effects of Agkistrodon viperid snake species and subspecies (eleven venoms total) on plasma clotting times, fibrinogen levels, and fibrin clot strength. Significant delays in plasma clotting time were observed for A. conanti, A. contortrix mokasen, A. contortrix phaeogaster, A. howardgloydi, A. piscivorus leucostoma, and A. piscivorus piscivorus. Notably, the phylogenetically disjunct lineages A. conanti, A. contortrix mokasen, and A. howardgloydi exhibited the most potent anticoagulant effects, indicating the independent amplification of a basal trait. Inhibition assays with the activated clotting enzymes Factors XIa, IXa, Xa, and IIa (thrombin) revealed that FXa inhibition is another basal trait amplified independently on multiple occasions within the genus, but with A. howardgloydi, notably more potent than all others. Phospholipid degradation and zymogen destruction were identified as mechanisms underlying the variability in venom effects observed experimentally and in previous clinical reports. Thromboelastography demonstrated that the venoms did not clot fibrinogen directly but affected fibrin clot strength by damaging fibrinogen and that thrombin was subsequently only able to cleave into weak, unstable clots. The ability to activate Protein C, an endogenous anticoagulant enzyme, varied across species, with some venoms exceeding that of A. contortrix contortrix, which previously yielded the protein diagnostic agent Protac®. Phylogenetic analysis suggested that both fibrinogen degradation and Protein C activation were each amplified multiple times within the genus, albeit with negative correlation between these two modes of action. This study highlights the evolutionary, clinical, and biodiscovery implications of venom variability in the Agkistrodon species, underscoring their dynamic evolution, emphasising the need for tailored clinical approaches, and highlighting the potential for novel diagnostic and therapeutic developments inspired by the unique properties of snake venoms.
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Affiliation(s)
- Francisco C. P. Coimbra
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
| | - Elda E. Sanchez
- National Natural Toxins Research Center, Department of Chemistry, Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA;
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - Juan J. Calvete
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, CSIC, 46010 Valencia, Spain;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
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Dobson J, Chowdhury A, Tai-A-Pin J, van der Ploeg H, Gillett A, Fry BG. The Clot Thickens: Differential Coagulotoxic and Cardiotoxic Activities of Anguimorpha Lizard Venoms. Toxins (Basel) 2024; 16:283. [PMID: 38922177 PMCID: PMC11209219 DOI: 10.3390/toxins16060283] [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: 05/29/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Despite their evolutionary novelty, lizard venoms are much less studied in comparison to the intense research on snake venoms. While the venoms of helodermatid lizards have long been assumed to be for defensive purposes, there is increasing evidence of toxic activities more useful for predation than defence (such as paralytic neurotoxicity). This study aimed to ascertain the effects of Heloderma, Lanthanotus, and Varanus lizard venoms on the coagulation and cardiovascular systems. Anticoagulant toxicity was demonstrated for the Varanus species studied, with the venoms prolonging clotting times in human and bird plasma due to the destructive cleavage of fibrinogen. In contrast, thromboelastographic analyses on human and bird plasmas in this study demonstrated a procoagulant bioactivity for Heloderma venoms. A previous study on Heloderma venom using factor-depleted plasmas as a proxy model suggested a procoagulant factor was present that activated either Factor XI or Factor XII, but could not ascertain the precise target. Our activation studies using purified zymogens confirmed FXII activation. Comparisons of neonate and adult H. exasperatum, revealed the neonates to be more potent in the ability to activate FXII, being more similar to the venom of the smaller species H. suspectum than the adult H. exasperatum. This suggests potent FXII activation a basal trait in the genus, present in the small bodied last common ancestor. This also indicates an ontogenetic difference in prey preferences in the larger Heloderma species paralleing the change in venom biochemistry. In addition, as birds lack Factor XII, the ability to clot avian plasma suggested an additional procoagulant site of action, which was revealed to be the activation of Factor VII, with H. horridum being the most potent. This study also examined the effects upon the cardiovascular system, including the liberation of kinins from kininogen, which contributes to hypotension induction. This form of toxicity was previously described for Heloderma venoms, and was revealed in this study was to also be a pathophysiological effect of Lanthanotus and Varanus venoms. This suggests that this toxic activity was present in the venom of the last common ancestor of the anguimorph lizards, which is consistent with kallikrein enzymes being a shared toxin trait. This study therefore uncovered novel actions of anguimorph lizard venoms, not only contributing to the evolutionary biology body of knowledge but also revealing novel activities to mine for drug design lead compounds.
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Affiliation(s)
- James Dobson
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | - Abhinandan Chowdhury
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | | | - Harold van der Ploeg
- Working Group Adder Research Netherlands, RAVON, 6525 ED Nijmegen, The Netherlands;
| | - Amber Gillett
- FaunaVet Wildlife Consultancy, Glass House Mountains, QLD 4518, Australia;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
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Albulescu LO, Westhorpe A, Clare RH, Woodley CM, James N, Kool J, Berry NG, O’Neill PM, Casewell NR. Optimizing drug discovery for snakebite envenoming via a high-throughput phospholipase A2 screening platform. Front Pharmacol 2024; 14:1331224. [PMID: 38273832 PMCID: PMC10808766 DOI: 10.3389/fphar.2023.1331224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 01/27/2024] Open
Abstract
Snakebite envenoming is a neglected tropical disease that causes as many as 1.8 million envenomings and 140,000 deaths annually. To address treatment limitations that exist with current antivenoms, the search for small molecule drug-based inhibitors that can be administered as early interventions has recently gained traction. Snake venoms are complex mixtures of proteins, peptides and small molecules and their composition varies substantially between and within snake species. The phospholipases A2 (PLA2) are one of the main pathogenic toxin classes found in medically important viper and elapid snake venoms, yet varespladib, a drug originally developed for the treatment of acute coronary syndrome, remains the only PLA2 inhibitor shown to effectively neutralise venom toxicity in vitro and in vivo, resulting in an extremely limited drug portfolio. Here, we describe a high-throughput drug screen to identify novel PLA2 inhibitors for repurposing as snakebite treatments. We present method optimisation of a 384-well plate, colorimetric, high-throughput screening assay that allowed for a throughput of ∼2,800 drugs per day, and report on the screening of a ∼3,500 post-phase I repurposed drug library against the venom of the Russell's viper, Daboia russelii. We further explore the broad-spectrum inhibitory potential and efficacy of the resulting top hits against a range of medically important snake venoms and demonstrate the utility of our method in determining drug EC50s. Collectively, our findings support the future application of this method to fully explore the chemical space to discover novel PLA2-inhibiting drugs of value for preventing severe pathology caused by snakebite envenoming.
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Affiliation(s)
- Laura-Oana Albulescu
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rachel H. Clare
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Nivya James
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Neil G. Berry
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Paul M. O’Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Puzari U, Goswami M, Rani K, Patra A, Mukherjee AK. Computational and in vitro analyses to identify the anticoagulant regions of Echicetin, a snake venom anticoagulant C-type lectin (snaclec): possibility to develop anticoagulant peptide therapeutics? J Biomol Struct Dyn 2023; 41:15569-15583. [PMID: 36994880 DOI: 10.1080/07391102.2023.2191138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 03/05/2023] [Indexed: 03/31/2023]
Abstract
Snake venom C-type lectins (Snaclecs) display anticoagulant and platelet-modulating activities; however, their interaction with the critical components of blood coagulation factors was unknown. Computational analysis revealed that Echicetin (Snaclec from Echis carinatus venom) interacted with heavy chain of thrombin, and heavy and light chains of factor Xa (FXa). Based on FXa and thrombin binding regions of Echicetin, the two synthetic peptides (1A and 1B) were designed. The in silico binding studies of the peptides with thrombin and FXa showed that peptide 1B interacted with both heavy and light chains of thrombin and, peptide 1A interacted with only heavy chain of thrombin. Similarly, peptide 1B interacted with both heavy and light chains of FXa; however, peptide 1A interacted only with heavy chain of FXa. Alanine screening predicted the hot-spots residues for peptide 1A (Aspartic acid6, Valine8, Valine9, and Tyrosine17 with FXa, and Isoleucine14, Lysine15 with thrombin) and peptide 1B (Valine16 with FXa). Spectrofluorometric interaction study showed a lower Kd value for peptide 1B binding with both FXa and thrombin than peptide 1A, indicating higher binding strength of the former peptide. The circular dichroism spectroscopy also established the interaction between thrombin and the custom peptides. The in vitro study demonstrated higher anticoagulant activity of peptide 1B than peptide 1A due to higher inhibition of thrombin and FXa. Inhibition of anticoagulant activity of the peptides by respective anti-peptide antibodies corroborates our hypothesis that peptides 1A and 1B represent the anticoagulant regions of Echicetin and may be developed as antithrombotic peptide drug prototypes.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Upasana Puzari
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Mahasweta Goswami
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Komal Rani
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Aparup Patra
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, Assam, India
| | - Ashis K Mukherjee
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, Assam, India
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A current perspective on snake venom composition and constituent protein families. Arch Toxicol 2023; 97:133-153. [PMID: 36437303 DOI: 10.1007/s00204-022-03420-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/09/2022] [Indexed: 11/28/2022]
Abstract
Snake venoms are heterogeneous mixtures of proteins and peptides used for prey subjugation. With modern proteomics there has been a rapid expansion in our knowledge of snake venom composition, resulting in the venom proteomes of 30% of vipers and 17% of elapids being characterised. From the reasonably complete proteomic coverage of front-fanged snake venom composition (179 species-68 species of elapids and 111 species of vipers), the venoms of vipers and elapids contained 42 different protein families, although 18 were only reported in < 5% of snake species. Based on the mean abundance and occurrence of the 42 protein families, they can be classified into 4 dominant, 6 secondary, 14 minor, and 18 rare protein families. The dominant, secondary and minor categories account for 96% on average of a snake's venom composition. The four dominant protein families are: phospholipase A2 (PLA2), snake venom metalloprotease (SVMP), three-finger toxins (3FTx), and snake venom serine protease (SVSP). The six secondary protein families are: L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRiSP), C-type lectins (CTL), disintegrins (DIS), kunitz peptides (KUN), and natriuretic peptides (NP). Venom variation occurs at all taxonomic levels, including within populations. The reasons for venom variation are complex, as variation is not always associated with geographical variation in diet. The four dominant protein families appear to be the most important toxin families in human envenomation, being responsible for coagulopathy, neurotoxicity, myotoxicity and cytotoxicity. Proteomic techniques can be used to investigate the toxicological profile of a snake venom and hence identify key protein families for antivenom immunorecognition.
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Chowdhury A, Youngman NJ, Liu J, Lewin MR, Carter RW, Fry BG. The relative efficacy of chemically diverse small-molecule enzyme-inhibitors against anticoagulant activities of Black Snake (Pseudechis spp.) venoms. Toxicol Lett 2022; 366:26-32. [PMID: 35788045 DOI: 10.1016/j.toxlet.2022.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/31/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
Snakebite remains a worldwide public health burden and a severely neglected tropical disease. Recent research has begun to focus on the potential use of repurposed small-molecule enzyme-inhibitors as early treatments to neutralise the effects of snake venoms. Black snakes (Pseudechis spp.) are a widespread and dangerously venomous group found throughout Australia and New Guinea. Utilising validated coagulation assays, our study assessed the efficacy of two chemically different small molecule inhibitors, a phospholipase A2 inhibitor (varespladib) and a metalloproteinase inhibitor (prinomastat), in vitro neutralisation of the anticoagulant prothrombinase-inhibiting activity of venom from seven species within the Pseudechis genus (P. australis, P. butleri, P. coletti, P. guttatus, P. papuanus, P.rossignolii, P. sp (NT).). Varespladib was shown to be highly effective at neutralising this anticoagulant activity for all seven species, but with P. coletti notably less so than the others. In contrast, prinomastat showed strong neutralisation for five out of the seven species, but was ineffective at neutralising the activity of P. coletti or P. rossignolii venoms. This suggests that varespladib binds to a highly conserved site but that prinomastat binds to a more variable site. These results build upon recent literature indicating that metalloproteinase inhibitors have cross-neutralising potential towards snake venom phospholipase A2 toxins, but with higher degrees of variability that PLA2-specific inhibitors. An important caveat is that these are in vitro tests and while suggestive of potential clinical utility, in vivo animal testing and clinical trials are required as future work.
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Affiliation(s)
- Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia QLD, 4072 Australia; Department of Biochemistry & Microbiology, North South University, Dhaka 1229, Bangladesh.
| | - Nicholas J Youngman
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia QLD, 4072 Australia
| | - Jiaojiao Liu
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia QLD, 4072 Australia
| | - Matthew R Lewin
- California Academy of Sciences, San Francisco, CA, 94118, USA; Ophirex, Inc., Corte Madera, CA, 94925, USA
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia QLD, 4072 Australia.
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Martos-Esteban A, Macleod OJS, Maudlin I, Kalogeropoulos K, Jürgensen JA, Carrington M, Laustsen AH. Black-necked spitting cobra (Naja nigricollis) phospholipases A 2 may cause Trypanosoma brucei death by blocking endocytosis through the flagellar pocket. Sci Rep 2022; 12:6394. [PMID: 35430620 PMCID: PMC9013370 DOI: 10.1038/s41598-022-10091-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/25/2022] [Indexed: 11/09/2022] Open
Abstract
African trypanosomes, such as Trypanosoma brucei, are flagellated protozoa which proliferate in mammals and cause a variety of diseases in people and animals. In a mammalian host, the external face of the African trypanosome plasma membrane is covered by a densely packed coat formed of variant surface glycoprotein (VSG), which counteracts the host's adaptive immune response by antigenic variation. The VSG is attached to the external face of the plasma membrane by covalent attachment of the C-terminus to glycosylphosphatidylinositol. As the trypanosome grows, newly synthesised VSG is added to the plasma membrane by vesicle fusion to the flagellar pocket, the sole location of exo- and endocytosis. Snake venoms contain dozens of components, including proteases and phospholipases A2. Here, we investigated the effect of Naja nigricollis venom on T. brucei with the aim of describing the response of the trypanosome to hydrolytic attack on the VSG. We found no evidence for VSG hydrolysis, however, N. nigricollis venom caused: (i) an enlargement of the flagellar pocket, (ii) the Rab11 positive endosomal compartments to adopt an abnormal dispersed localisation, and (iii) cell cycle arrest prior to cytokinesis. Our results indicate that a single protein family, the phospholipases A2 present in N. nigricollis venom, may be necessary and sufficient for the effects. This study provides new molecular insight into T. brucei biology and possibly describes mechanisms that could be exploited for T. brucei targeting.
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Affiliation(s)
| | - Olivia J S Macleod
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Isabella Maudlin
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | | | - Jonas A Jürgensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Andreas H Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
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Chowdhury A, Lewin MR, Zdenek CN, Carter R, Fry BG. The Relative Efficacy of Chemically Diverse Small-Molecule Enzyme-Inhibitors Against Anticoagulant Activities of African Spitting Cobra ( Naja Species) Venoms. Front Immunol 2021; 12:752442. [PMID: 34691069 PMCID: PMC8529177 DOI: 10.3389/fimmu.2021.752442] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/22/2021] [Indexed: 11/23/2022] Open
Abstract
African spitting cobras are unique among cobras for their potent anticoagulant venom activity arising from strong inhibition of Factor Xa. This anticoagulant effect is exerted by venom phospholipase A2 (Group I PLA2) toxins whose activity contributes to the lethality of these species. This anticoagulant toxicity is particularly problematic as it is not neutralized by current antivenoms. Previous work demonstrated this trait for Naja mossambica, N. nigricincta, N. nigricollis, and N. pallida. The present work builds upon previous research by testing across the full taxonomical range of African spitting cobras, demonstrating that N. ashei, N. katiensis, and N. nubiae are also potently anticoagulant through the inhibition of Factor Xa, and therefore the amplification of potent anticoagulant activity occurred at the base of the African spitting cobra radiation. Previous work demonstrated that the enzyme-inhibitor varespladib was able to neutralize this toxic action for N. mossambica, N. nigricincta, N. nigricollis, and N. pallida venoms. The current work demonstrates that varespladib was also able to neutralize N. ashei, N. katiensis, and N. nubiae. Thus varespladib is shown to have broad utility across the full range of African spitting cobras. In addition, we examined the cross-reactivity of the metalloprotease inhibitor prinomastat, which had been previously intriguingly indicated as being capable of neutralizing viperid venom PLA2 (Group II PLA2). In this study prinomastat inhibited the FXa-inhibiting PLA2 toxins of all the African spitting cobras at the same concentration at which it has been shown to inhibit metalloproteases, and thus was comparably effective in its cross-reactivity. In addition we showed that the metalloprotease-inhibitor marimastat was also able to cross-neutralize PLA2 but less effectively than prinomastat. Due to logistical (cold-chain requirement) and efficacy (cross-reactivity across snake species) limitations of traditional antivenoms, particularly in developing countries where snakebite is most common, these small molecule inhibitors (SMIs) might hold great promise as initial, field-based, treatments for snakebite envenoming as well as addressing fundamental limitations of antivenom in the clinical setting where certain toxin effects are unneutralized.
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Affiliation(s)
- Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia.,Department of Biochemistry & Microbiology, North South University, Dhaka, Bangladesh
| | - Matthew R Lewin
- California Academy of Sciences, San Francisco, CA, United States.,Ophirex, Inc., Corte Madera, CA, United States
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
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11
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Kazandjian TD, Arrahman A, Still KBM, Somsen GW, Vonk FJ, Casewell NR, Wilkinson MC, Kool J. Anticoagulant Activity of Naja nigricollis Venom Is Mediated by Phospholipase A2 Toxins and Inhibited by Varespladib. Toxins (Basel) 2021; 13:toxins13050302. [PMID: 33922825 PMCID: PMC8145175 DOI: 10.3390/toxins13050302] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/07/2021] [Accepted: 04/18/2021] [Indexed: 12/03/2022] Open
Abstract
Bites from elapid snakes typically result in neurotoxic symptoms in snakebite victims. Neurotoxins are, therefore, often the focus of research relating to understanding the pathogenesis of elapid bites. However, recent evidence suggests that some elapid snake venoms contain anticoagulant toxins which may help neurotoxic components spread more rapidly. This study examines the effects of venom from the West African black-necked spitting cobra (Naja nigricollis) on blood coagulation and identifies potential coagulopathic toxins. An integrated RPLC-MS methodology, coupled with nanofractionation, was first used to separate venom components, followed by MS, proteomics and coagulopathic bioassays. Coagulation assays were performed on both crude and nanofractionated N. nigricollis venom toxins as well as PLA2s and 3FTx purified from the venom. Assays were then repeated with the addition of either the phospholipase A2 inhibitor varespladib or the snake venom metalloproteinase inhibitor marimastat to assess whether either toxin inhibitor is capable of neutralizing coagulopathic venom activity. Subsequent proteomic analysis was performed on nanofractionated bioactive venom toxins using tryptic digestion followed by nanoLC-MS/MS measurements, which were then identified using Swiss-Prot and species-specific database searches. Varespladib, but not marimastat, was found to significantly reduce the anticoagulant activity of N. nigricollis venom and MS and proteomics analyses confirmed that the anticoagulant venom components mostly consisted of PLA2 proteins. We, therefore, conclude that PLA2s are the most likely candidates responsible for anticoagulant effects stimulated by N. nigricollis venom.
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Affiliation(s)
- Taline D. Kazandjian
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (T.D.K.); (N.R.C.)
| | - Arif Arrahman
- Department of Chemistry and Pharmaceutical Sciences, Division of Bioanalytical Chemistry, Faculty of Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands; (A.A.); (K.B.M.S.); (G.W.S.)
- Centre for Analytical Sciences Amsterdam (CASA), 1012WX Amsterdam, The Netherlands
- Faculty of Pharmacy, Kampus Baru UI, Universitas Indonesia, Depok 16424, Indonesia
| | - Kristina B. M. Still
- Department of Chemistry and Pharmaceutical Sciences, Division of Bioanalytical Chemistry, Faculty of Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands; (A.A.); (K.B.M.S.); (G.W.S.)
- Centre for Analytical Sciences Amsterdam (CASA), 1012WX Amsterdam, The Netherlands
| | - Govert W. Somsen
- Department of Chemistry and Pharmaceutical Sciences, Division of Bioanalytical Chemistry, Faculty of Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands; (A.A.); (K.B.M.S.); (G.W.S.)
- Centre for Analytical Sciences Amsterdam (CASA), 1012WX Amsterdam, The Netherlands
| | - Freek J. Vonk
- Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands;
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (T.D.K.); (N.R.C.)
| | - Mark C. Wilkinson
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (T.D.K.); (N.R.C.)
- Correspondence: (M.C.W.); (J.K.)
| | - Jeroen Kool
- Department of Chemistry and Pharmaceutical Sciences, Division of Bioanalytical Chemistry, Faculty of Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands; (A.A.); (K.B.M.S.); (G.W.S.)
- Centre for Analytical Sciences Amsterdam (CASA), 1012WX Amsterdam, The Netherlands
- Correspondence: (M.C.W.); (J.K.)
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12
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Dashevsky D, Bénard-Valle M, Neri-Castro E, Youngman NJ, Zdenek CN, Alagón A, Portes-Junior JA, Frank N, Fry BG. Anticoagulant Micrurus venoms: Targets and neutralization. Toxicol Lett 2020; 337:91-97. [PMID: 33197555 DOI: 10.1016/j.toxlet.2020.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/30/2020] [Accepted: 11/09/2020] [Indexed: 11/26/2022]
Abstract
Snakebite is a neglected tropical disease with a massive global burden of injury and death. The best current treatments, antivenoms, are plagued by a number of logistical issues that limit supply and access in remote or poor regions. We explore the anticoagulant properties of venoms from the genus Micrurus (coral snakes), which have been largely unstudied, as well as the effectiveness of antivenom and a small-molecule phospholipase inhibitor-varespladib-at counteracting these effects. Our in vitro results suggest that these venoms likely interfere with the formation or function of the prothrombinase complex. We find that the anticoagulant potency varies widely across the genus and is especially pronounced in M. laticollaris. This variation does not appear to correspond to previously described patterns regarding the relative expression of the three-finger toxin and phospholipase A2 (PLA2) toxin families within the venoms of this genus. The coral snake antivenom Coralmyn, is largely unable to ameliorate these effects except for M. ibiboboca. Varespladib on the other hand completely abolished the anticoagulant activity of every venom. This is consistent with the growing body of results showing that varespladib may be an effective treatment for a wide range of toxicity caused by PLA2 toxins from many different snake species. Varespladib is a particularly attractive candidate to help alleviate the burden of snakebite because it is an approved drug that possesses several logistical advantages over antivenom including temperature stability and oral availability.
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Affiliation(s)
- Daniel Dashevsky
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072 Australia; Australian National Insect Collection, Commonwealth Science and Industry Research Organization, Canberra, ACT 2601 Australia
| | - Melisa Bénard-Valle
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, Mexico
| | - Edgar Neri-Castro
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, Mexico
| | - Nicholas J Youngman
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072 Australia
| | - Christina N Zdenek
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072 Australia
| | - Alejandro Alagón
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, Mexico
| | - José A Portes-Junior
- Laboratório de Coleções Zoológicas, Instituto Butantan, São Paulo 05503-900, Brazil
| | | | - Bryan G Fry
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072 Australia.
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13
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Youngman NJ, Walker A, Naude A, Coster K, Sundman E, Fry BG. Varespladib (LY315920) neutralises phospholipase A 2 mediated prothrombinase-inhibition induced by Bitis snake venoms. Comp Biochem Physiol C Toxicol Pharmacol 2020; 236:108818. [PMID: 32512199 DOI: 10.1016/j.cbpc.2020.108818] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 05/26/2020] [Accepted: 06/02/2020] [Indexed: 01/28/2023]
Abstract
Anticoagulant toxicity is a common function of venoms produced by species within the Bitis genus. Potent inhibition of the prothrombinase complex is an identified mechanism of action for the dwarf species B. cornuta and B. xeropaga, along with some localities of B. atropos and B. caudalis. Snake venom phospholipase A2 toxins that inhibit the prothrombinase complex have been identified in snake venom, including an isolated phospholipase A2 toxin from B. caudalis. Current research is investigating the ability of the drug varespladib to inhibit snake venom phospholipase A2 toxins and reduce their toxicity. In particular, varespladib is being investigated as a treatment that could be administered prior to hospital referral which is a major necessity for species such as those from the genus Bitis, due to envenomations often occurring in remote regions of Africa where antivenom is unavailable. Using previously validated coagulation assays, this study aimed to determine if the toxins responsible for inhibition of the prothrombinase complex in the venom of four Bitis species are phospholipase A2 toxins, and if varespladib is able to neutralise this anticoagulant activity. Our results demonstrate that varespladib strongly neutralises the prothrombinase-inhibiting effects of all venoms tested in this study, and that this prothrombinase-inhibiting mechanism of anticoagulant activity is driven by phospholipase A2 class toxins in these four species. This study extends previous reports demonstrating varespladib has broad efficacy for treatment of phospholipase A2 rich snake venoms, indicating it also inhibits their anticoagulant effects mediated by prothrombinase-inhibition.
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Affiliation(s)
- Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Andrew Walker
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD 4072, Australia
| | - Arno Naude
- Snakebite Assist, Pretoria ZA-0001, South Africa
| | | | - Eric Sundman
- Universeum, Södra Vägen 50, 412 54 Gothenburg, Sweden
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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14
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Xie C, Albulescu LO, Still KBM, Slagboom J, Zhao Y, Jiang Z, Somsen GW, Vonk FJ, Casewell NR, Kool J. Varespladib Inhibits the Phospholipase A 2 and Coagulopathic Activities of Venom Components from Hemotoxic Snakes. Biomedicines 2020; 8:E165. [PMID: 32560391 PMCID: PMC7345350 DOI: 10.3390/biomedicines8060165] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/04/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022] Open
Abstract
Phospholipase A2 (PLA2) enzymes are important toxins found in many snake venoms, and they can exhibit a variety of toxic activities including causing hemolysis and/or anticoagulation. In this study, the inhibiting effects of the small molecule PLA2 inhibitor varespladib on snake venom PLA2s was investigated by nanofractionation analytics, which combined chromatography, mass spectrometry (MS), and bioassays. The venoms of the medically important snake species Bothrops asper, Calloselasma rhodostoma, Deinagkistrodon acutus, Daboia russelii, Echis carinatus, Echis ocellatus, and Oxyuranus scutellatus were separated by liquid chromatography (LC) followed by nanofractionation and interrogation of the fractions by a coagulation assay and a PLA2 assay. Next, we assessed the ability of varespladib to inhibit the activity of enzymatic PLA2s and the coagulopathic toxicities induced by fractionated snake venom toxins, and identified these bioactive venom toxins and those inhibited by varespladib by using parallel recorded LC-MS data and proteomics analysis. We demonstrated here that varespladib was not only capable of inhibiting the PLA2 activities of hemotoxic snake venoms, but can also effectively neutralize the coagulopathic toxicities (most profoundly anticoagulation) induced by venom toxins. While varespladib effectively inhibited PLA2 toxins responsible for anticoagulant effects, we also found some evidence that this inhibitory molecule can partially abrogate procoagulant venom effects caused by different toxin families. These findings further emphasize the potential clinical utility of varespladib in mitigating the toxic effects of certain snakebites.
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Affiliation(s)
- Chunfang Xie
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
| | - Laura-Oana Albulescu
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.-O.A.); (N.R.C.)
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Kristina B. M. Still
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
| | - Julien Slagboom
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
| | - Yumei Zhao
- Institute of Pharmaceutical Analysis, College of Pharmacy, Jinan University, Huangpu Avenue West 601, Guangzhou 510632, China; (Y.Z.); (Z.J.)
| | - Zhengjin Jiang
- Institute of Pharmaceutical Analysis, College of Pharmacy, Jinan University, Huangpu Avenue West 601, Guangzhou 510632, China; (Y.Z.); (Z.J.)
| | - Govert W. Somsen
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
| | - Freek J. Vonk
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
- Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.-O.A.); (N.R.C.)
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Jeroen Kool
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; (C.X.); (K.B.M.S.); (J.S.); (G.W.S.); (F.J.V.)
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH Amsterdam, The Netherlands
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15
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Zdenek CN, Youngman NJ, Hay C, Dobson J, Dunstan N, Allen L, Milanovic L, Fry BG. Anticoagulant activity of black snake (Elapidae: Pseudechis) venoms: Mechanisms, potency, and antivenom efficacy. Toxicol Lett 2020; 330:176-184. [PMID: 32442717 DOI: 10.1016/j.toxlet.2020.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Venoms from Pseudechis species (Australian black snakes) within the Elapidae family are rich in anticoagulant PLA2 toxins, with the exception of one species (P. porphyriacus) that possesses procoagulant mutated forms of the clotting enzyme Factor Xa. Previously the mechanism of action of the PLA2 toxins' anticoagulant toxicity was said to be due to inhibition of Factor Xa, but this statement was evidence free. We conducted a series of anticoagulation assays to elucidate the mechanism of anticoagulant action produced by P. australis venom. Our results revealed that, rather than targeting FXa, the PLA2 toxins inhibited the prothrombinase complex, with FVa-alone or as part of the prothrombinase complex-as the primary target; but with significant thrombin inhibition also noted. In contrast, FXa, and other factors inhibited only to a lesser degree were minor targets. We quantified coagulotoxic effects upon human plasma caused by all nine anticoagulant Pseudechis species, including nine localities of P. australis across Australia, and found similar anticoagulant potency across all Pseudechis species, with greater potency in P. australis and the undescribed Pseudechis species in the NT. In addition, the northern localities and eastern of P. australis were significantly more potent than the central, western, and southern localities. All anticoagulant venoms responded well to Black Snake Antivenom, except P. colletti which was poorly neutralised by Black Snake Antivenom and also Tiger Snake Antivenom (the prescribed antivenom for this species). However, we found LY315920 (trade name: Varespladib), a small molecule inhibitor of PLA2 proteins, exhibited strong potency against P. colletti venom. Thus, Varespladib may be a clinically viable treatment for anticoagulant toxicity exerted by this species that is not neutralised by available antivenoms. Our results provide insights into coagulotoxic venom function, and suggest future in vivo work be conducted to progress the development of a cheaper, first-line treatment option to treat PLA2-rich snake venoms globally.
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Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Chris Hay
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia; Australian School of Herpetology, Southport, QLD, Australia
| | - James Dobson
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA, 5352, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA, 5352, Australia
| | - Leontina Milanovic
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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Factor XII-Deficient Chicken Plasma as a Useful Target for Screening of Pro- and Anticoagulant Animal Venom Toxins. Toxins (Basel) 2020; 12:toxins12020079. [PMID: 31979411 PMCID: PMC7076771 DOI: 10.3390/toxins12020079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 11/24/2022] Open
Abstract
The sensitivity of vertebrate citrated plasma to pro- and anticoagulant venom or toxins occurs on a microscale level (micrograms). Although it improves responses to agonists, recalcification triggers a relatively fast thrombin formation process in mammalian plasma. As it has a natural factor XII deficiency, the recalcification time (RT) of chicken plasma (CP) is comparatively long [≥ 1800 seconds (s)]. Our objective was to compare the ability of bee venom phospholipase A2 (bvPLA2) to neutralize clot formation induced by an activator of coagulation (the aPTT clot) in recalcified human and chicken plasmas, through rotational thromboelastometry. The strategy used in this study was to find doses of bvPLA2 that were sufficient enough to prolong the clotting time (CT) of these activated plasmas to values within their normal RT range. The CT of CP was prolonged in a dose-dependent manner by bvPLA2, with 17 ± 2.8 ng (n = 6) being sufficient to displace the CT values of the activated samples to ≥ 1800 s. Only amounts up to 380 ± 41 ng (n = 6) of bvPLA2 induced the same effect in activated human plasma samples. In conclusion, the high sensitivity of CP to agonists and rotational thromboelastometry could be useful. For example, during screening procedures for assaying the effects of toxins in several stages of the coagulation pathway, such as clot initiation, formation, stability, strength, or dissolution.
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17
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Comparative analysis of Naja kaouthia venom from North-East India and Bangladesh and its cross reactivity with Indian polyvalent antivenoms. Toxicon 2019; 164:31-43. [DOI: 10.1016/j.toxicon.2019.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/26/2019] [Accepted: 03/31/2019] [Indexed: 01/01/2023]
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18
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Sousa ID, Barbosa AR, Salvador GH, Frihling BE, Santa-Rita PH, Soares AM, Pessôa HL, Marchi-Salvador DP. Secondary hemostasis studies of crude venom and isolated proteins from the snake Crotalus durissus terrificus. Int J Biol Macromol 2019; 131:127-133. [DOI: 10.1016/j.ijbiomac.2019.03.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 03/09/2019] [Accepted: 03/09/2019] [Indexed: 10/27/2022]
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19
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Mud in the blood: Novel potent anticoagulant coagulotoxicity in the venoms of the Australian elapid snake genus Denisonia (mud adders) and relative antivenom efficacy. Toxicol Lett 2019; 302:1-6. [DOI: 10.1016/j.toxlet.2018.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/23/2018] [Accepted: 11/26/2018] [Indexed: 11/18/2022]
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20
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Naja annulifera Snake: New insights into the venom components and pathogenesis of envenomation. PLoS Negl Trop Dis 2019; 13:e0007017. [PMID: 30657756 PMCID: PMC6338361 DOI: 10.1371/journal.pntd.0007017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 11/23/2018] [Indexed: 11/19/2022] Open
Abstract
Background Naja annulifera is a medically important venomous snake occurring in some of the countries in Sub-Saharan Africa. Accidental bites result in severe coagulation disturbances, systemic inflammation and heart damage, as reported in dogs, and death, by respiratory arrest, in humans. Despite the medical importance of N. annulifera, little is known about its venom composition and the pathogenesis of envenomation. In this paper, the toxic, inflammatory and immunogenic properties of N. annulifera venom were analyzed. Methodology/Principal findings Venom proteomic analysis identified 79 different proteins, including Three Finger Toxins, Cysteine Rich Secretory Proteins, Metalloproteinases, Phospholipases A2 (PLA2), Hyaluronidase, L-amino-acid oxidase, Cobra Venom Factor and Serine Proteinase. The presence of PLA2, hyaluronidase, fibrinogenolytic and anticoagulant activities was detected using functional assays. The venom was cytotoxic to human keratinocytes. In an experimental murine model of envenomation, it was found that the venom induced local changes, such as swelling, which was controlled by anti-inflammatory drugs. Moreover, the venom caused death, which was preceded by systemic inflammation and pulmonary hemorrhage. The venom was shown to be immunogenic, inducing a strong humoral immune response, with the production of antibodies able to recognize venom components with high molecular weight and to neutralize its lethal activity. Conclusions/Significance The results obtained in this study demonstrate that N. annulifera venom contains toxins able to induce local and systemic inflammation, which can contribute to lung damage and death. Moreover, the venom is immunogenic, an important feature that must be considered during the production of a therapeutic anti-N. annulifera antivenom. N. annulifera is a dangerous snake that belongs to the Elapidae family. It is found in some of the countries in Sub-Saharan Africa and has caused accidents in humans and dogs. In this study, we characterized some of the biochemical, toxic and immunogenic properties of N. annulifera venom. We showed that the venom is composed of several proteins, some of which display enzymatic activities, such as phospholipase A2, hyaluronidase, metalloproteinases and serine proteinases. The venom promoted disturbances in the human coagulation system and was cytotoxic to human epidermal cells. Using a mouse model, we showed that the venom promotes local reactions that were reduced with anti-inflammatory drugs. The venom caused systemic inflammation, lung hemorrhage and death. Further, the venom stimulated production of high antibody titers when injected into mice and the antiserum produced was able to inhibit venom-induced death. This study demonstrated that N. annulifera venom contains toxins that trigger inflammatory process, which may contribute to the envenomation pathology. Moreover, the venom is immunogenic, an important aspect for the production of an efficient N. annulifera antivenom.
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Bittenbinder MA, Zdenek CN, Op den Brouw B, Youngman NJ, Dobson JS, Naude A, Vonk FJ, Fry BG. Coagulotoxic Cobras: Clinical Implications of Strong Anticoagulant Actions of African Spitting Naja Venoms That Are Not Neutralised by Antivenom but Are by LY315920 (Varespladib). Toxins (Basel) 2018; 10:toxins10120516. [PMID: 30518149 PMCID: PMC6316626 DOI: 10.3390/toxins10120516] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/27/2018] [Accepted: 12/01/2018] [Indexed: 01/15/2023] Open
Abstract
Snakebite is a global tropical disease that has long had huge implications for human health and well-being. Despite its long-standing medical importance, it has been the most neglected of tropical diseases. Reflective of this is that many aspects of the pathology have been underinvestigated. Snakebite by species in the Elapidae family is typically characterised by neurotoxic effects that result in flaccid paralysis. Thus, while clinically significant disturbances to the coagulation cascade have been reported, the bulk of the research to date has focused upon neurotoxins. In order to fill the knowledge gap regarding the coagulotoxic effects of elapid snake venoms, we screened 30 African and Asian venoms across eight genera using in vitro anticoagulant assays to determine the relative inhibition of the coagulation function of thrombin and the inhibition of the formation of the prothrombinase complex through competitive binding to a nonenzymatic site on Factor Xa (FXa), thereby preventing FXa from binding to Factor Va (FVa). It was revealed that African spitting cobras were the only species that were potent inhibitors of either clotting factor, but with Factor Xa inhibited at 12 times the levels of thrombin inhibition. This is consistent with at least one death on record due to hemorrhage following African spitting cobra envenomation. To determine the efficacy of antivenom in neutralising the anticoagulant venom effects, for the African spitting cobras we repeated the same 8-point dilution series with the addition of antivenom and observed the shift in the area under the curve, which revealed that the antivenom performed extremely poorly against the coagulotoxic venom effects of all species. However, additional tests with the phospholipase A2 inhibitor LY315920 (trade name: varespladib) demonstrated a powerful neutralisation action against the coagulotoxic actions of the African spitting cobra venoms. Our research has important implications for the clinical treatment of cobra snakebites and also sheds light on the molecular mechanisms involved in coagulotoxicity within Naja. As the most coagulotoxic species are also those that produce characteristic extreme local tissue damage, future research should investigate potential synergistic actions between anticoagulant toxins and cytotoxins.
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Affiliation(s)
- Mátyás A Bittenbinder
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
- Institute of Biology, Leiden University, 2300 RA Leiden, The Netherlands.
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
| | - James S Dobson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Arno Naude
- Snakebite Assist, Pretoria ZA-0001, South Africa.
| | - Freek J Vonk
- Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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A functional and thromboelastometric-based micromethod for assessing crotoxin anticoagulant activity and antiserum relative potency against Crotalus durissus terrificus venom. Toxicon 2018; 148:26-32. [PMID: 29654870 DOI: 10.1016/j.toxicon.2018.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/05/2018] [Accepted: 04/10/2018] [Indexed: 11/20/2022]
Abstract
The assessment of the capacity of antivenoms to neutralize the lethal activity of snake venoms still relies on traditional rodent in vivo lethality assay. ED50 and LD50 assays require large quantities of venoms and antivenoms, and besides leading to animal suffering. Therefore, in vitro tests should be introduced for assessing antivenom neutralizing capacity in intermediary steps of antivenom production. This task is facilitated when one key lethal toxin is identified. A good example is crotoxin, a β-neurotoxin phospholipase A2-like toxin that presents anticoagulant activity in vitro and is responsible for the lethality of venoms of Crotalus durissus snakes. By using rotational thromboelastometry, we reported recently one sensitive coagulation assay for assessing relative potency of the anti-bothropic serum in neutralizing procoagulant activity of Bothrops jararaca venom upon recalcified factor-XII-deficient chicken plasma samples (CPS). In this study, we stablished conditions for determining relative potency of four batches of the anti-crotalic serum (ACS) (antagonist) in inactivating crotoxin anticoagulant activity in CPS (target) simultaneously treated with one classical activator of coagulation (agonists). The correlation coefficient (r) between values related the ACS potency in inactivating both in vitro crotoxin anticoagulant activity and the in vivo lethality of whole venom (ED50) was 0.94 (p value < 0.05). In conclusion, slowness in spontaneous thrombin/fibrin generation even after recalcification elicit time lapse sufficient for elaboration of one dose-response curve to pro- or anti-coagulant agonists in CPS. We propose this methodology as an alternative and sensitive assay for assessing antivenom neutralizing ability in plasma of immunized horses as well as for in-process quality control.
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Kang TS, Chen W, Goh LC, Kini M. Identification and characterisation of novel inhibitors on extrinsic tenase complex from Bungarus fasciatus (banded krait) venom. Thromb Haemost 2017; 112:700-15. [DOI: 10.1160/th13-12-1063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 05/06/2014] [Indexed: 11/05/2022]
Abstract
SummarySnake venoms are excellent sources of pharmacologically active proteins and peptides, and hence are potential sources of leads for drug developments. It has been previously established that krait (Bungarus genus) venoms contain mainly neurotoxins. A screening for anticoagulants showed that Bungarus fasciatus venom exhibits potent anticoagulant effect in standard clotting assays. Through sequential fractionation of the venom by size exclusion and high performance liquid chromatographies, coupled with functional screening for anticoagulant activities, we have isolated and purified two anticoagulant proteins, termed BF-AC1 ( Bungarus fasciatus anticoagulant 1) and BFAC2. They have potent inhibitory activities (IC50 of 10 nM) on the extrinsic tenase complex. Structurally, these proteins each has two subunits covalently held together by disulfide bond(s). The N-terminal sequences of the individual subunits of BF-AC1 and BF-AC2 showed that the larger subunit is homologous to phospholipase A2, while the smaller subunit is homologous to Kunitz type serine proteinase inhibitor. Functionally, in addition to their anticoagulant activity, these proteins showed presynaptic neurotoxic effects in both in vivo and ex vivo experiments. Thus, BF-AC1 and BF-AC2 are structurally and functionally similar to β-bungarotoxins, a class of neurotoxins. The enzymatic activity of phospholipase A2 subunit plays a significant role in the anticoagulant activities. This is the first report on the anticoagulant activity of β-bungarotoxins and these results expand on the existing catalogue of haemostatically active snake venom proteins.
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Snake Venom PLA 2, a Promising Target for Broad-Spectrum Antivenom Drug Development. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6592820. [PMID: 29318152 PMCID: PMC5727668 DOI: 10.1155/2017/6592820] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/30/2017] [Indexed: 12/04/2022]
Abstract
Snakebite envenomation is a neglected global health problem, causing substantial mortality, disability, and psychological morbidity, especially in rural tropical and subtropical zones. Antivenin is currently the only specific medicine for envenomation. However, it is restricted by cold storage, snakebite diagnosis, and high price. Snake venom phospholipase A2s (svPLA2s) are found in all kinds of venomous snake families (e.g., Viperidae, Elapidae, and Colubridae). Along with their catalytic activity, svPLA2s elicit a wide variety of pharmacological effects that play a pivotal role in envenomation damage. Hence, neutralization of the svPLA2s could weaken or inhibit toxic damage. Here we overviewed the latest knowledge on the distribution, pathophysiological effects, and inhibitors of svPLA2s to elucidate the potential for a novel, wide spectrum antivenom drug targeting svPLA2s.
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Abdou F, Denshary EE, Shaaban E, Mohamed M. Assessment of the neutralizing potency of antisera raised against native and γ-irradiated Naja nigricollis (black-necked spitting cobra) venom in rabbits, concerning its cardiotoxic effect. Hum Exp Toxicol 2017; 36:1335-1344. [PMID: 28905664 DOI: 10.1177/0960327117730880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study was designed to prepare a specific safe antiserum for Naja nigricollis using γ-irradiated (1.5KGy and3KGy) venoms. Rabbits were used for active immunization using irradiated venoms (1.5 and 3 kGy) as a toxoid, mice were used for determination of LD50 post immunization and the rats were used for neutralization of the cardiotoxic effect of venom. Results of the immunodiffusion test indicated that the sera of rabbits raised against non-irradiated, 1.5- and 3-kGy γ-irradiated venom, had the same results of precipitin bands. A significant inhibition of phospholipase A2 activities was obtained when neutralized with native, γ-irradiated (1.5KGy and3KGy) venoms. On the other hand, preincubation of the venom ½ LD50 (0.154 mg/kg i.p.) with each antiserum (non-irradiated or irradiated venom) at 37°C for 1 h in a ratio (1:4) produced a significant reduction in the values of creatine kinase and creatine kinase isoenzyme-MB. However, significant elevation in aspartate aminotransferase level and no change in lactate dehydrogenase level were observed. So the results of this study indicated that the irradiated venom treatment reduces the cardiotoxic effect of venom in immunized immunization animals for preparing vaccines.
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Affiliation(s)
- F Abdou
- 1 Department of Drug Radiation Research, National Center for Radiation Research and Technology - Atomic Energy Authority, Nasr City, Cairo, Egypt
| | - E E Denshary
- 2 Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Giza, Egypt
| | - E Shaaban
- 1 Department of Drug Radiation Research, National Center for Radiation Research and Technology - Atomic Energy Authority, Nasr City, Cairo, Egypt
| | - M Mohamed
- 1 Department of Drug Radiation Research, National Center for Radiation Research and Technology - Atomic Energy Authority, Nasr City, Cairo, Egypt
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Oliveira FDR, Noronha MDDN, Lozano JLL. Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis. Rev Soc Bras Med Trop 2017; 50:365-373. [DOI: 10.1590/0037-8682-0408-2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 04/11/2017] [Indexed: 11/22/2022] Open
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Du QS, Trabi M, Richards RS, Mirtschin P, Madaras F, Nouwens A, Zhao KN, de Jersey J, Lavin MF, Guddat LW, Masci PP. Characterization and structural analysis of a potent anticoagulant phospholipase A2 from Pseudechis australis snake venom. Toxicon 2016; 111:37-49. [DOI: 10.1016/j.toxicon.2015.12.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/22/2015] [Accepted: 12/28/2015] [Indexed: 11/24/2022]
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Accary C, Mantash A, Mallem Y, Fajloun Z, Elkak A. Separation and Biological Activities of Phospholipase A2 (Mb-PLA2) from the Venom of Montivipera bornmuelleri, a Lebanese Viper. J LIQ CHROMATOGR R T 2015. [DOI: 10.1080/10826076.2014.968660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Claudine Accary
- Azm Center for Research in Biotechnology and its Applications, Doctoral School of Sciences and Technology, Lebanese University, Tripoli, Lebanon
| | - Aziza Mantash
- Laboratory of “Valorisation des Ressources Naturelles et Produits de Santé (VRNPS),” Doctoral School of Sciences and Technology, Lebanese University, Rafic Hariri University Campus, Hadath, Lebanon
| | - Yassine Mallem
- LUNAM, Oniris, Unit of Animal Pathophysiology and Functional Pharmacology, Nantes, France
| | - Ziad Fajloun
- Azm Center for Research in Biotechnology and its Applications, Doctoral School of Sciences and Technology, Lebanese University, Tripoli, Lebanon
| | - Assem Elkak
- Laboratory of “Valorisation des Ressources Naturelles et Produits de Santé (VRNPS),” Doctoral School of Sciences and Technology, Lebanese University, Rafic Hariri University Campus, Hadath, Lebanon
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Saikia D, Majumdar S, Mukherjee AK. Mechanism of in vivo anticoagulant and haemolytic activity by a neutral phospholipase A(2) purified from Daboia russelii russelii venom: correlation with clinical manifestations in Russell's Viper envenomed patients. Toxicon 2013; 76:291-300. [PMID: 24125661 DOI: 10.1016/j.toxicon.2013.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 09/27/2013] [Accepted: 10/02/2013] [Indexed: 10/26/2022]
Abstract
A 13.0 kDa neutral phospholipase A2 (NEUPHOLIPASE) purified from venom of Daboia russelii russelii from eastern India was identified by peptide mass fingerprinting analysis. It exerted dose-dependent PLA2, anticoagulant and indirect haemolytic activities. NEUPHOLIPASE showed preferential binding followed by hydrolysis of phosphatidylserine > phosphatidylcholine >> phosphatidylethanolamine. Circular dichroism analysis of NEUPHOLIPASE showed a high content of alpha helix (54.6%) followed by beta-turn (29.7%) in its secondary structure. Gas-chromatographic analysis of plasma from PLA2-treated mice suggested preferential hydrolysis of pro-coagulant phospholipid PS was the primary mechanism to account for in vivo anticoagulant effect of NEUPHOLIPASE. The NEUPHOLIPASE-treated mice blood showed a significant decrease (p < 0.01) in WBC as well as RBC counts with a corresponding decline in Hb content due to indirect damage to erythrocyte membranes by plasma phospholipids hydrolysis products rather than the direct haemolytic activity of PLA2 under study. NEUPHOLIPASE was non-lethal to BALB/c mice, however; it was detrimental to liver of treated-mice. Pathological symptoms observed in NEUPHOLIPASE-treated mice were correlated with the actual clinical manifestations in Russell's Viper envenomed patients from eastern India indicating some contribution of NEUPHOLIPASE in Russell's Viper venom induced toxicity and pathogenesis.
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Affiliation(s)
- Debashree Saikia
- Microbial Biotechnology and Protein Research Laboratory, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam 784028, India
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Ostrowski M, Žnidaršič PP, Raynal B, Saul F, Faure G. Human coagulation factor Xa prevents oligomerization of anti-coagulant phospholipases A2. TOXIN REV 2013. [DOI: 10.3109/15569543.2013.860170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Snake bites and hemostasis/thrombosis. Thromb Res 2013; 132:642-6. [PMID: 24125598 DOI: 10.1016/j.thromres.2013.09.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 09/18/2013] [Accepted: 09/18/2013] [Indexed: 11/21/2022]
Abstract
Snake venom toxins have evolved to affect many prey physiological systems including hemostasis and thrombosis. These toxins belong to a diverse array of protein families and can initiate or inhibit multiple stages of the coagulation pathway or platelet aggregation with incredible specificity. Such specificity toward vertebrate molecular targets has made them extremely useful for diagnosis of human diseases or as molecular scalpels in physiological studies. The large number of yet-to-be characterized venoms provides a vast potential source of novel toxins and subsequent cardiovascular therapeutics and diagnostic agents.
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Antitumoral potential of Tunisian snake venoms secreted phospholipases A2. BIOMED RESEARCH INTERNATIONAL 2013; 2013:391389. [PMID: 23509718 PMCID: PMC3581298 DOI: 10.1155/2013/391389] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 09/04/2012] [Indexed: 11/17/2022]
Abstract
Phospholipases type A2 (PLA2s) are the most abundant proteins found in Viperidae snake venom. They are quite fascinating from both a biological and structural point of view. Despite similarity in their structures and common catalytic properties, they exhibit a wide spectrum of pharmacological activities. Besides being hydrolases, secreted phospholipases A2 (sPLA2) are an important group of toxins, whose action at the molecular level is still a matter of debate. These proteins can display toxic effects by different mechanisms. In addition to neurotoxicity, myotoxicity, hemolytic activity, antibacterial, anticoagulant, and antiplatelet effects, some venom PLA2s show antitumor and antiangiogenic activities by mechanisms independent of their enzymatic activity. This paper aims to discuss original finding against anti-tumor and anti-angiogenic activities of sPLA2 isolated from Tunisian vipers: Cerastes cerastes and Macrovipera lebetina, representing new tools to target specific integrins, mainly, α5β1 and αv integrins.
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Wadood A, Ali SA, Sattar R, Lodhi MA, Ul-Haq Z. A novel pharmacophore model to identify leads for simultaneous inhibition of anti-coagulation and anti-inflammatory activities of snake venom phospholipase A(2). Chem Biol Drug Des 2012; 79:431-41. [PMID: 22136624 DOI: 10.1111/j.1747-0285.2011.01281.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In addition to catalytic action, snake venom phospholipase A(2) induces several pharmacological effects including neurotoxicity, cardiotoxicity as well as anti-coagulant and anti-platelet aggregation effects. Therefore, strategy to identify dual inhibitor for this enzyme will be of much importance in medical research. In this paper, structure-based pharmacophore mapping, molecular docking, protein-ligand interaction fingerprints, binding energy calculations, and binding affinity predictions were employed in a virtual screening strategy to identify new hits for dual inhibition of anti-coagulation and inflammation of phospholipase A(2) . A structure-based pharmacophore map was modeled which comprised of important interactions as observed in co-crystal of phospholipase A(2) and its dual inhibitor indomethacin. The generated model was used to retrieve molecules from ChemBridge, a free database of commercially available compounds. A total of 381 molecules mapped on the developed pharmacophore model from ChemBridge database. The hits retrieved were further screened by molecular docking, protein-ligand interaction fingerprints, binding energy calculations, and binding affinity predictions using Genetic Optimization for Ligand Docking and moe. Based on these results, 32 chemo-types molecules were predicted as potential lead scaffolds for developing novel, potent and structurally diverse dual inhibitor of phospholipase A(2.).
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Affiliation(s)
- Abdul Wadood
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
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Salazar AM, Vivas J, Sánchez EE, Rodríguez-Acosta A, Ibarra C, Gil A, Carvajal Z, Girón ME, Estrella A, Navarrete LF, Guerrero B. Hemostatic and toxinological diversities in venom of Micrurus tener tener, Micrurus fulvius fulvius and Micrurus isozonus coral snakes. Toxicon 2011; 58:35-45. [PMID: 21596052 PMCID: PMC3304457 DOI: 10.1016/j.toxicon.2011.04.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 04/21/2011] [Accepted: 04/26/2011] [Indexed: 10/18/2022]
Abstract
The coral snake Micrurus tener tener (Mtt) from the Elapidae family inhabits the southwestern United States and produces severe cases of envenomations. Although the majority of Mtt venom components are neurotoxins and phospholipase A₂s, this study demonstrated, by SDS-PAGE and molecular exclusion chromatography (MEC), that these venoms also contain high-molecular-weight proteins between 50 and 150 kDa that target the hemostatic system. The biological aspects of other Micrurus venoms were also studied, such as the LD₅₀s of Micrurus isozonus (from 0.52 to 0.61 mg/kg). A pool from these venoms presented a LD₅₀ of 0.57 mg/kg, Micrurus f. fulvius (Mff) and Mtt had LD₅₀s of 0.32 and 0.78 mg/kg, respectively. These venoms contained fibrino(geno)lytic activity, they inhibited platelet aggregation, as well as factor Xa and/or plasmin-like activities. M. isozonus venoms from different Venezuelan geographical regions inhibited ADP-induced platelet aggregation (from 50 to 68%). Micrurus tener tener venom from the United States was the most active with a 95.2% inhibitory effect. This venom showed thrombin-like activity on fibrinogen and human plasma. Fractions of Mtt showed fibrino(geno)lytic activity and inhibition on plasmin amidolytic activity. Several fractions degraded the fibrinogen Aα chains, and fractions F2 and F7 completely degraded both fibrinogen Aα and Bβ chains. To our knowledge, this is the first report on thrombin-like and fibrino(geno)lytic activity and plasmin or factor Xa inhibitors described in Micrurus venoms. Further purification and characterization of these Micrurus venom components could be of therapeutic use in the treatment of hemostatic disorders.
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Affiliation(s)
- Ana M. Salazar
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
| | - Jeilyn Vivas
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
| | - Elda E. Sánchez
- Department of Chemistry and The National Natural Toxins Research Center, Texas A & M University-Kingsville, Kingsville, TX 78363, USA
| | - Alexis Rodríguez-Acosta
- Sección de Inmunoquímica, Instituto de Medicina Tropical de la Universidad Central de Venezuela, Caracas, Venezuela
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico de la Universidad Central de Venezuela, Caracas, Venezuela
| | - Carlos Ibarra
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
| | - Amparo Gil
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
| | - Zoila Carvajal
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
| | - María E. Girón
- Sección de Inmunoquímica, Instituto de Medicina Tropical de la Universidad Central de Venezuela, Caracas, Venezuela
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico de la Universidad Central de Venezuela, Caracas, Venezuela
| | - Amalid Estrella
- Sección de Inmunoquímica, Instituto de Medicina Tropical de la Universidad Central de Venezuela, Caracas, Venezuela
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico de la Universidad Central de Venezuela, Caracas, Venezuela
| | - Luis F. Navarrete
- Sección de Inmunoquímica, Instituto de Medicina Tropical de la Universidad Central de Venezuela, Caracas, Venezuela
| | - Belsy Guerrero
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020A, Venezuela
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Sajevic T, Leonardi A, Križaj I. Haemostatically active proteins in snake venoms. Toxicon 2011; 57:627-45. [PMID: 21277886 DOI: 10.1016/j.toxicon.2011.01.006] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 11/16/2022]
Abstract
Snake venom proteins that affect the haemostatic system can cause (a) lowering of blood coagulability, (b) damage to blood vessels, resulting in bleeding, (c) secondary effects of bleeding, e.g. hypovolaemic shock and organ damage, and (d) thrombosis. These proteins may, or may not, be enzymes. We review the data on the most relevant haemostatically active proteinases, phospholipases A₂, L-amino acid oxidases and 5'-nucleotidases from snake venoms. We also survey the non-enzymatic effectors of haemostasis from snake venoms--disintegrins, C-type lectins and three-finger toxins. Medical applications have already been found for some of these snake venom proteins. We describe those that have already been approved as drugs to treat haemostatic disorders or are being used to diagnose such health problems. No clinical applications, however, currently exist for the majority of snake venom proteins acting on haemostasis. We conclude with the most promising potential uses in this respect.
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Affiliation(s)
- Tamara Sajevic
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
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Antisnake Venom Activity of Hibiscus aethiopicus L. against Echis ocellatus and Naja n. nigricollis. J Toxicol 2010; 2010:837864. [PMID: 20628507 PMCID: PMC2902021 DOI: 10.1155/2010/837864] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 11/26/2022] Open
Abstract
The objective of the study is to investigate whether the Hibiscus aethiopicus L. plant has neutralization activity against venoms of two clinically important snakes. The H. aethiopicus was dried and extracted with water. Different assays were performed to evaluate the plant's acute toxicity and its anti-snake venom activities. The results showed that H. aethiopicus extract alone had no effect on the viability of C2C12 muscle cells, but significantly (P < .05) protected muscle cells against the toxic effects of E. ocellatus venom at 55, 150, and 300 μg/mL. The maximum protective effect of the extract was exhibited at 75 μg/mL. The extract significantly (P < .001) inhibited the cytotoxic effects of E. ocellatus venom at 300 μg/mL. All rabbits (n = 10) and guinea pigs (n = 10) were alive after the two weeks of given the lethal dosage 16 g/Kg of the H. aethiopicus extract herbal solution. No abnormal behaviour was observed of both groups of animals. All guinea pigs (n = 3) treated with venoms alone (5 mg/kg) died. However, all guinea pigs (n = 21) treated with venom (5 mg/kg) and the extract (400 to 1000 mg/kg) survived. Guinea pigs (n = 3) treated with Naja n. nigricollis venom alone (2.5 mg/kg) and guinea pigs (n = 21) venom with the extract (400 to 1000 mg/kg) died. The H. aethiopicus completely (100%) blocked the haemorrhagic activity of E. ocellatus in the egg embryo at 3.3 mg/mL of extract. These findings suggest that H. aethiopicus may contain an endogenous inhibitor of venom-induced haemorrhage.
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Lonomia obliqua venom: In vivo effects and molecular aspects associated with the hemorrhagic syndrome. Toxicon 2010; 56:1103-12. [PMID: 20114060 DOI: 10.1016/j.toxicon.2010.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Revised: 01/06/2010] [Accepted: 01/19/2010] [Indexed: 11/22/2022]
Abstract
Caterpillar envenomation has been an emergent health issue. Lonomia obliqua is a medically important animal that causes a hemorrhagic syndrome that can progress to acute renal failure, intracranial hemorrhage and death. In the past few years the molecular characterization of L. obliqua venom in addition to experimental models has provided fundamental information to the understanding of the envenomation syndrome. Herein studies from several authors which characterized the complex toxic-pharmacological actions of whole venom are reviewed.
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Singh N, Kumar RP, Kumar S, Sharma S, Mir R, Kaur P, Srinivasan A, Singh TP. Simultaneous inhibition of anti-coagulation and inflammation: crystal structure of phospholipase A2 complexed with indomethacin at 1.4 A resolution reveals the presence of the new common ligand-binding site. J Mol Recognit 2009; 22:437-45. [PMID: 19462410 DOI: 10.1002/jmr.960] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A novel ligand-binding site with functional implications has been identified in phospholipase A(2) (PLA(2)). The binding of non-steroidal anti-inflammatory agent indomethacin at this site blocks both catalytic and anti-coagulant actions of PLA(2). A group IIA PLA(2) has been isolated from Daboia russelli pulchella (Russell's viper) which is enzymatically active as well as induces a strong anti-coagulant action. The binding studies have shown that indomethacin reduces the effects of both anti-coagulant and pro-inflammatory actions of PLA(2). A group IIA PLA(2) was co-crystallized with indomethacin and the structure of the complex has been determined at 1.4 A resolution. The structure determination has revealed the presence of an indomethacin molecule in the structure of PLA(2) at a site which is distinct from the conventional substrate-binding site. One of the carboxylic group oxygen atoms of indomethacin interacts with Asp 49 and His 48 through the catalytically important water molecule OW 18 while the second carboxylic oxygen atom forms an ionic interaction with the side chain of Lys 69. It is well known that the residues, His 48 and Asp 49 are essential for catalysis while Lys 69 is a part of the anti-coagulant loop (residues, 54-77). Indomethacin binds in such a manner that it blocks the access to both, it works as a dual inhibitor for catalytic and anti-coagulant actions of PLA(2). This new binding site in PLA(2) has been observed for the first time and indomethacin is the first compound that has been shown to bind at this novel site resulting in the prevention of anti-coagulation and inflammation.
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Affiliation(s)
- Nagendra Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110 029, India
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Atanasov VN, Danchev D, Mitewa M, Petrova S. Hemolytic and anticoagulant study of the neurotoxin vipoxin and its components—basic phospholipase A2 and an acidic inhibitor. BIOCHEMISTRY (MOSCOW) 2009; 74:276-80. [DOI: 10.1134/s0006297909030055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zingali RB. INTERACTION OF SNAKE-VENOM PROTEINS WITH BLOOD COAGULATION FACTORS: MECHANISMS OF ANTICOAGULANT ACTIVITY. TOXIN REV 2008. [DOI: 10.1080/15569540600567412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Guerranti R, Ogueli IG, Bertocci E, Muzzi C, Aguiyi JC, Cianti R, Armini A, Bini L, Leoncini R, Marinello E, Pagani R. Proteomic analysis of the pathophysiological process involved in the antisnake venom effect of Mucuna pruriens extract. Proteomics 2008; 8:402-12. [PMID: 18203263 DOI: 10.1002/pmic.200700265] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Previously, we reported the antisnake venom properties of a Mucuna pruriens seed extract (MPE) and tested its in vivo efficacy against Echis carinatus venom (EV) in short- (1 injection) and long-term (three weekly injections) treatments. The aim of the present study was to investigate plasma proteome changes associated with MPE treatments and identify proteins responsible for survival of envenomated mice (CHALLENGED mice). Six treatment groups were studied. Three control groups: one saline, one short-term and one long-term MPE treatment. One group received EV alone. Two test groups received EV with either a short-term or long-term MPE treatment (CHALLENGED mice). The plasma from each group was analysed by 2-DE/MALDI-TOF MS. The most significant changes with treatment were: albumin, haptoglobin, fibrinogen, serum amyloid A and serum amyloid P. Most of these changes were explained by EV effects on coagulation, inflammation and haemolysis. However, MPE treatments prevented the EV-induced elevation in HPT. Consequently, HPT levels were similar to controls in the plasma of CHALLENGED mice. The plasma of CHALLENGED mice showed substantial proteomic modifications. This suggests the mechanism of MPE protection involves the activation of counterbalancing processes to compensate for the imbalances caused by EV.
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Affiliation(s)
- Roberto Guerranti
- Department of Internal Medicine, Endocrine-Metabolic Sciences and Biochemistry, University of Siena, Via A. Moro 2, Siena, Italy.
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Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics. BMC STRUCTURAL BIOLOGY 2007; 7:82. [PMID: 18062812 PMCID: PMC2248580 DOI: 10.1186/1472-6807-7-82] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 12/06/2007] [Indexed: 11/20/2022]
Abstract
Background The snake venom group IIA secreted phospholipases A2 (SVPLA2), present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL) at the membrane/water interface and by highly specific direct binding to: (i) presynaptic membrane-bound or intracellular receptors; (ii) natural PLA2-inhibitors from snake serum; and (iii) coagulation factors present in human blood. Results Using surface plasmon resonance (SPR) protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa) via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-β-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS). The interface in FXa involves both, the light and heavy chains. Conclusion We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors.
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Abstract
Over the last several decades, research on snake venom toxins has provided not only new tools to decipher molecular details of various physiological processes, but also inspiration to design and develop a number of therapeutic agents. Blood circulation, particularly thrombosis and haemostasis, is one of the major targets of several snake venom proteins. Among them, anticoagulant proteins have contributed to our understanding of molecular mechanisms of blood coagulation and have provided potential new leads for the development of drugs to treat or to prevent unwanted clot formation. Some of these anticoagulants exhibit various enzymatic activities whereas others do not. They interfere in normal blood coagulation by different mechanisms. Although significant progress has been made in understanding the structure-function relationships and the mechanisms of some of these anticoagulants, there are still a number of questions to be answered as more new anticoagulants are being discovered. Such studies contribute to our fight against unwanted clot formation, which leads to death and debilitation in cardiac arrest and stroke in patients with cardiovascular and cerebrovascular diseases, arteriosclerosis and hypertension. This review describes the details of the structure, mechanism and structure-function relationships of anticoagulant proteins from snake venoms.
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Affiliation(s)
- R Manjunatha Kini
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore.
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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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Prijatelj P, Charnay M, Ivanovski G, Jenko Z, Pungercar J, Krizaj I, Faure G. The C-terminal and β-wing regions of ammodytoxin A, a neurotoxic phospholipase A2 from Vipera ammodytes ammodytes, are critical for binding to factor Xa and for anticoagulant effect. Biochimie 2006; 88:69-76. [PMID: 16039772 DOI: 10.1016/j.biochi.2005.06.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Accepted: 06/21/2005] [Indexed: 11/25/2022]
Abstract
Ammodytoxin A (AtxA) from the venom of Vipera ammodytes ammodytes belongs to group IIA secreted phospholipase A2 (sPLA2), for which the major pathologic activity is presynaptic neurotoxicity. We show here that this toxin also affects hemostasis because it exhibits strong anticoagulant activity. AtxA binds directly to human coagulation factor Xa (FXa) with Kdapp of 32 nM, thus inhibiting the activity of the prothrombinase complex with an IC50 of 20 nM. To map the FXa-interaction site on AtxA, various mutants of AtxA produced by site-directed mutagenesis and expressed in Escherichia coli were tested in the study. In surface plasmon resonance (SPR) measurements, with FXa covalently attached to the sensor chip, we show that the FXa-binding site on AtxA includes several basic amino acid residues at the C-terminal and beta-wing regions of the molecule. Applying an in vitro biological test for inhibition of prothrombinase activity, we further demonstrate that the same residues are also very important for the anticoagulant activity of AtxA. We conclude that the anticoagulant site of AtxA is located in the C-terminal and beta-wing regions of this phospholipase A2. Synthetic peptides comprising residues of the deduced anticoagulant site of AtxA provide a basis to synthesize novel anticoagulant drugs.
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Affiliation(s)
- Petra Prijatelj
- Unité des Venins, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris cedex 15, France
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Banerjee Y, Mizuguchi J, Iwanaga S, Kini RM. Hemextin AB Complex, a Unique Anticoagulant Protein Complex from Hemachatus haemachatus (African Ringhals Cobra) Venom That Inhibits Clot Initiation and Factor VIIa Activity. J Biol Chem 2005; 280:42601-11. [PMID: 16204244 DOI: 10.1074/jbc.m508987200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During injury or trauma, blood coagulation is initiated by the interaction of factor VIIa (FVIIa) in the blood with freshly exposed tissue factor (TF) to form the TF.FVIIa complex. However, unwanted clot formation can lead to death and debilitation due to vascular occlusion, and hence, anticoagulants are important for the treatment of thromboembolic disorders. Here, we report the isolation and characterization of two synergistically acting anticoagulant proteins, hemextins A and B, from the venom of Hemachatus haemachatus (African Ringhals cobra). N-terminal sequences and CD spectra of the native proteins indicate that these proteins belong to the three-finger toxin family. Hemextin A (but not hemextin B) exhibits mild anticoagulant activity. However, hemextin B forms a complex (hemextin AB complex) with hemextin A and synergistically enhances its anticoagulant potency. Prothrombin time assay showed that these two proteins form a 1:1 complex. Complex formation was supported by size-exclusion chromatography. Using a "dissection approach," we determined that hemextin A and the hemextin AB complex prolong clotting by inhibiting TF.FVIIa activity. The site of anticoagulant effects was supported by their inhibitory effect on the reconstituted TF.FVIIa complex. Furthermore, we demonstrated their specificity of inhibition by studying their effects on 12 serine proteases; the hemextin AB complex potently inhibited the amidolytic activity of FVIIa in the presence and absence of soluble TF. Kinetic studies showed that the hemextin AB complex is a noncompetitive inhibitor of soluble TF.FVIIa amidolytic activity, with a Ki of 50 nm. Isothermal titration calorimetric studies showed that the hemextin AB complex binds directly to FVIIa with a binding constant of 1.62 x 10(5) m(-1). The hemextin AB complex is the first reported natural inhibitor of FVIIa that does not require a scaffold to mediate its inhibitory activity. Molecular interactions of the hemextin AB complex with FVIIa/TF.FVIIa will provide a new paradigm in the search for anticoagulants that inhibit the initiation of blood coagulation.
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Affiliation(s)
- Yajnavalka Banerjee
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science, National University of Singapore Singapore 117543
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Kini RM. Structure–function relationships and mechanism of anticoagulant phospholipase A2 enzymes from snake venoms. Toxicon 2005; 45:1147-61. [PMID: 15922780 DOI: 10.1016/j.toxicon.2005.02.018] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Phospholipase A(2) (PLA(2)) enzymes from snake venom are toxic and induce a wide spectrum of pharmacological effects, despite similarity in primary, secondary and tertiary structures and common catalytic properties. Thus, the structure-function relationships and the mechanism of this group of small proteins are subtle, complex and intriguing challenges. This review, taking the PLA(2) enzymes from spitting cobra (Naja nigricollis) venom as examples, describes the mechanism of anticoagulant effects. The strongly anticoagulant CM-IV inhibits both the extrinsic tenase and prothrombinase complexes, whereas the weakly anticoagulant PLA(2) enzymes (CM-I and CM-II) inhibit only the extrinsic tenase complex. CM-IV binds to factor Xa and interferes in its interaction with factor Va and the formation of prothrombinase complex. In contrast, CM-I and CM-II do not affect the formation of prothrombinase complex. In addition, CM-IV inhibits the extrinsic tenase complex by a combination of enzymatic and nonenzymatic mechanisms, while CM-I and CM-II inhibit by only enzymatic mechanism. These functional differences explain the disparity in the anticoagulant potency of N. nigricollis PLA(2) enzymes. Similarly, human secretory enzyme binds to factor Xa and inhibits the prothrombinase complex. We predicted the anticoagulant region of PLA(2) enzymes using a systematic and direct comparison of amino acid sequences. This region between 54 and 77 residues is basic in the strongly anticoagulant PLA(2) enzymes and neutral or negatively charged in weakly and non-anticoagulant enzymes. The prediction is validated independently by us and others using both site directed mutagenesis and synthetic peptides. Thus, strongly anticoagulant CM-IV binds to factor Xa (its target protein) through the specific anticoagulant site on its surface. In contrast, weakly anticoagulant enzymes, which lack the anticoagulant region fail to bind specifically to the target protein, factor Xa in the coagulation cascade. Thus, these studies strongly support the target model which suggests that protein-protein interaction rather than protein-phospholipid interaction determines the pharmacological specificity of PLA(2) enzymes.
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Affiliation(s)
- R Manjunatha Kini
- Protein Science Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
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Kini RM, Banerjee Y. Dissection approach: a simple strategy for the identification of the step of action of anticoagulant agents in the blood coagulation cascade. J Thromb Haemost 2005; 3:170-1. [PMID: 15634281 DOI: 10.1111/j.1538-7836.2004.01056.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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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Talhout R, Engberts JBFN. Thermodynamic analysis of binding ofp-substituted benzamidines to trypsin. ACTA ACUST UNITED AC 2003. [DOI: 10.1046/j.1432-1327.2001.01991.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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