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Misson Mindrebo LE, Mindrebo JT, Tran Q, Wilkinson MC, Smith JM, Verma M, Casewell NR, Lander GC, Jardine JG. Importance of the Cysteine-Rich Domain of Snake Venom Prothrombin Activators: Insights Gained from Synthetic Neutralizing Antibodies. Toxins (Basel) 2024; 16:361. [PMID: 39195771 PMCID: PMC11360484 DOI: 10.3390/toxins16080361] [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: 07/12/2024] [Revised: 08/07/2024] [Accepted: 08/13/2024] [Indexed: 08/29/2024] Open
Abstract
Snake venoms are cocktails of biologically active molecules that have evolved to immobilize prey, but can also induce a severe pathology in humans that are bitten. While animal-derived polyclonal antivenoms are the primary treatment for snakebites, they often have limitations in efficacy and can cause severe adverse side effects. Building on recent efforts to develop improved antivenoms, notably through monoclonal antibodies, requires a comprehensive understanding of venom toxins. Among these toxins, snake venom metalloproteinases (SVMPs) play a pivotal role, particularly in viper envenomation, causing tissue damage, hemorrhage and coagulation disruption. One of the current challenges in the development of neutralizing monoclonal antibodies against SVMPs is the large size of the protein and the lack of existing knowledge of neutralizing epitopes. Here, we screened a synthetic human antibody library to isolate monoclonal antibodies against an SVMP from saw-scaled viper (genus Echis) venom. Upon characterization, several antibodies were identified that effectively blocked SVMP-mediated prothrombin activation. Cryo-electron microscopy revealed the structural basis of antibody-mediated neutralization, pinpointing the non-catalytic cysteine-rich domain of SVMPs as a crucial target. These findings emphasize the importance of understanding the molecular mechanisms of SVMPs to counter their toxic effects, thus advancing the development of more effective antivenoms.
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Affiliation(s)
- Laetitia E. Misson Mindrebo
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, CA 92037, USA; (L.E.M.M.); (Q.T.)
- IAVI Neutralizing Antibody Center, Scripps Research Institute, La Jolla, CA 92037, USA
- International AIDS Vaccine Initiative, New York, NY 10004, USA
| | - Jeffrey T. Mindrebo
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA; (J.T.M.); (G.C.L.)
| | - Quoc Tran
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, CA 92037, USA; (L.E.M.M.); (Q.T.)
- IAVI Neutralizing Antibody Center, Scripps Research Institute, La Jolla, CA 92037, USA
- International AIDS Vaccine Initiative, New York, NY 10004, USA
| | - Mark C. Wilkinson
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK; (M.C.W.); (N.R.C.)
| | | | - Megan Verma
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, CA 92037, USA; (L.E.M.M.); (Q.T.)
- IAVI Neutralizing Antibody Center, Scripps Research Institute, La Jolla, CA 92037, USA
- International AIDS Vaccine Initiative, New York, NY 10004, USA
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK; (M.C.W.); (N.R.C.)
| | - Gabriel C. Lander
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA; (J.T.M.); (G.C.L.)
| | - Joseph G. Jardine
- Department of Immunology and Microbiology, Scripps Research Institute, La Jolla, CA 92037, USA; (L.E.M.M.); (Q.T.)
- IAVI Neutralizing Antibody Center, Scripps Research Institute, La Jolla, CA 92037, USA
- International AIDS Vaccine Initiative, New York, NY 10004, USA
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Zdenek CN, Rodrigues CFB, Bourke LA, Tanaka-Azevedo AM, Monagle P, Fry BG. Children and Snakebite: Snake Venom Effects on Adult and Paediatric Plasma. Toxins (Basel) 2023; 15:158. [PMID: 36828472 PMCID: PMC9961128 DOI: 10.3390/toxins15020158] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/26/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Snakebite is a globally neglected tropical disease, with coagulation disturbances being the primary pathology of many deadly snake venoms. Age-related differences in human plasma have been abundantly reported, yet the effect that these differences pose regarding snakebite is largely unknown. We tested for differences in coagulotoxic effects (via clotting time) of multiple snake venoms upon healthy human adult (18+) and paediatric (median 3.3 years old) plasma in vivo and compared these effects to the time it takes the plasmas to clot without the addition of venom (the spontaneous clotting time). We tested venoms from 15 medically significant snake species (from 13 genera) from around the world with various mechanisms of coagulotoxic actions, across the three broad categories of procoagulant, pseudo-procoagulant, and anticoagulant, to identify any differences between the two plasmas in their relative pathophysiological vulnerability to snakebite. One procoagulant venom (Daboia russelii, Russell's Viper) produced significantly greater potency on paediatric plasma compared with adult plasma. In contrast, the two anticoagulant venoms (Pseudechis australis, Mulga Snake; and Bitis cornuta, Many-horned Adder) were significantly more potent on adult plasma. All other procoagulant venoms and all pseudo-procoagulant venoms displayed similar potency across both plasmas. Our preliminary results may inform future studies on the effect of snake venoms upon plasmas from different age demographics and hope to reduce the burden of snakebite upon society.
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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
| | | | - Lachlan A. Bourke
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Anita Mitico Tanaka-Azevedo
- Laboratório de Herpetologia, Instituto Butantan, São Paulo 05508-040, SP, Brazil
- Programa de Pós-Graduação Interunidades Em Biotecnologia, USP, IPT e Instituto Butantan, São Paulo 05508-040, SP, Brazil
| | - Paul Monagle
- Department of Paediatrics, University of Melbourne, Parkville, VIC 3010, Australia
- Haematology Research, Murdoch children’s Research Institute, Flemington Rd., Parkville, VIC 3052, Australia
- Department of Clinical Haematology, Royal Children’s Hospital, Flemington Rd., Parkville, VIC 3052, Australia
- Kids Cancer Centre, Sydney Children’s Hospital, High St., Randwick, NSW 2031, Australia
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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3
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Zhao KN, Masci P, Dimeski G, Johnson L, Grant M, de Jersey J, Lavin MF. Potential Application of Recombinant Snake Prothrombin Activator Ecarin in Blood Diagnostics. Biomolecules 2022; 12:1704. [PMID: 36421717 PMCID: PMC9687618 DOI: 10.3390/biom12111704] [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: 10/05/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 08/30/2023] Open
Abstract
We describe here the purification and cloning of a codon-optimized form of the snake prothrombin activator ecarin from the saw scaled viper (Echis carinatus) expressed in mammalian cells. Expression of recombinant ecarin (rEcarin) was carried out in human embryonic kidney cells (HEK) cells under conditions for the development and performance of a novel and scalable recombinant snake ecarin to industry standards. Clotting performance of the rEcarin was established in recalcified citrated whole blood, plasma, and fresh whole blood and found to be comparable to native ecarin (N-Ecarin). Furthermore, hemolysis was observed with N-Ecarin at relatively high doses in both recalcified citrated and fresh whole blood, while clotting was not observed with rEcarin, providing an important advantage for the recombinant form. In addition, rEcarin effectively clotted both recalcified citrated whole blood and fresh whole blood containing different anticoagulants including heparin, warfarin, dabigatran, Fondaparinux, rivaroxaban and apixaban, forming firm clots in the blood collection tubes. These results demonstrate that rEcarin efficiently clots normal blood as well as blood spiked with high concentrations of anticoagulants and has great potential as an additive to blood collection tubes to produce high quality serum for analyte analysis in diagnostic medicine.
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Affiliation(s)
- Kong-Nan Zhao
- Australian Institute of Biotechnology and Nanotechnology, St Lucia Campus, The University of Queensland, Brisbane, QLD 4072, Australia
- Centre for Kidney Disease Research-Venomics Research, School of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul Masci
- Centre for Kidney Disease Research-Venomics Research, School of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Goce Dimeski
- Chemical Pathology, Princess Alexandra Hospital, Woolloongabba, Brisbane, QLD 4102, Australia
- School of Chemistry and Molecular Biosciences, St Lucia Campus, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Lambro Johnson
- Australian Institute of Biotechnology and Nanotechnology, St Lucia Campus, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Michael Grant
- Q-Sera Pty Ltd., Level 9, 31 Queen St, Melbourne, VIC 3000, Australia
| | - John de Jersey
- School of Chemistry and Molecular Biosciences, St Lucia Campus, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Martin F. Lavin
- Australian Institute of Biotechnology and Nanotechnology, St Lucia Campus, The University of Queensland, Brisbane, QLD 4072, Australia
- Centre for Clinical Research, RBWH Campus, The University of Queensland, Brisbane, QLD 4029, Australia
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4
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Zdenek CN, Llinas J, Dobson J, Allen L, Dunstan N, Sousa LF, Moura da Silva AM, Fry BG. Pets in peril: The relative susceptibility of cats and dogs to procoagulant snake venoms. Comp Biochem Physiol C Toxicol Pharmacol 2020; 236:108769. [PMID: 32376497 DOI: 10.1016/j.cbpc.2020.108769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/07/2020] [Accepted: 04/18/2020] [Indexed: 11/27/2022]
Abstract
Snakebite is a common occurrence for pet cats and dogs worldwide and can be fatal. In Australia the eastern brown snake (Pseudonaja textilis) is responsible for an estimated 76% of reported snakebite cases to domestic pets nationally each year, with the primary pathology being venom-induced consumptive coagulopathy. While only 31% of dogs survive P. textilis bites without antivenom, cats are twice as likely to survive bites (66%). Even with antivenom treatment, cats have a significantly higher survival rate. The reason behind this disparity is unclear. Using a coagulation analyser (Stago STA R Max), we tested the relative procoagulant effects of P. textilis venom-as well as 10 additional procoagulant venoms found around the world-on cat and dog plasma in vitro, as well as on human plasma for comparison. All venoms acted faster upon dog plasma than cat or human, indicating that dogs would likely enter coagulopathic states sooner, and are thus more vulnerable to procoagulant snake venoms. The spontaneous clotting time (recalcified plasma with no venom added) was also substantially faster in dogs than in cats, suggesting that the naturally faster clotting blood of dogs predisposes them to being more vulnerable to procoagulant snake venoms. This is consistent with clinical records showing more rapid onset of symptoms and lethal effects in dogs than cats. Several behavioural differences between cats and dogs are also highly likely to disproportionately negatively affect prognosis in dogs. Thus, compared to cats, dogs require earlier snakebite first-aid and antivenom to prevent the onset of lethal venom effects.
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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.
| | | | - James Dobson
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Leijiane F Sousa
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
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Slagboom J, Mladić M, Xie C, Kazandjian TD, Vonk F, Somsen GW, Casewell NR, Kool J. High throughput screening and identification of coagulopathic snake venom proteins and peptides using nanofractionation and proteomics approaches. PLoS Negl Trop Dis 2020; 14:e0007802. [PMID: 32236099 PMCID: PMC7153897 DOI: 10.1371/journal.pntd.0007802] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 04/13/2020] [Accepted: 03/01/2020] [Indexed: 11/19/2022] Open
Abstract
Snakebite is a neglected tropical disease that results in a variety of systemic and local pathologies in envenomed victims and is responsible for around 138,000 deaths every year. Many snake venoms cause severe coagulopathy that makes victims vulnerable to suffering life-threating haemorrhage. The mechanisms of action of coagulopathic snake venom toxins are diverse and can result in both anticoagulant and procoagulant effects. However, because snake venoms consist of a mixture of numerous protein and peptide components, high throughput characterizations of specific target bioactives is challenging. In this study, we applied a combination of analytical and pharmacological methods to identify snake venom toxins from a wide diversity of snake species that perturb coagulation. To do so, we used a high-throughput screening approach consisting of a miniaturised plasma coagulation assay in combination with a venom nanofractionation approach. Twenty snake venoms were first separated using reversed-phase liquid chromatography, and a post-column split allowed a small fraction to be analyzed with mass spectrometry, while the larger fraction was collected and dispensed onto 384-well plates. After fraction collection, any solvent present in the wells was removed by means of freeze-drying, after which it was possible to perform a plasma coagulation assay in order to detect coagulopathic activity. Our results demonstrate that many snake venoms simultaneously contain both procoagulant and anticoagulant bioactives that contribute to coagulopathy. In-depth identification analysis from seven medically-important venoms, via mass spectrometry and nanoLC-MS/MS, revealed that phospholipase A2 toxins are frequently identified in anticoagulant venom fractions, while serine protease and metalloproteinase toxins are often associated with procoagulant bioactivities. The nanofractionation and proteomics approach applied herein seems likely to be a valuable tool for the rational development of next-generation snakebite treatments by facilitating the rapid identification and fractionation of coagulopathic toxins, thereby enabling specific targeting of these toxins by new therapeutics such as monoclonal antibodies and small molecule inhibitors.
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Affiliation(s)
- Julien Slagboom
- Division of BioAnalytical Chemistry, Amsterdam Institute for Molecules Medicines and Systems, VU University Amsterdam, Amsterdam, The Netherlands
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Marija Mladić
- Animal Sciences and Health, Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Chunfang Xie
- Division of BioAnalytical Chemistry, Amsterdam Institute for Molecules Medicines and Systems, VU University Amsterdam, Amsterdam, The Netherlands
| | - Taline D. Kazandjian
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Freek Vonk
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Govert W. Somsen
- Division of BioAnalytical Chemistry, Amsterdam Institute for Molecules Medicines and Systems, VU University Amsterdam, Amsterdam, The Netherlands
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Amsterdam Institute for Molecules Medicines and Systems, VU University Amsterdam, Amsterdam, The Netherlands
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6
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Kakumanu R, Kemp-Harper BK, Silva A, Kuruppu S, Isbister GK, Hodgson WC. An in vivo examination of the differences between rapid cardiovascular collapse and prolonged hypotension induced by snake venom. Sci Rep 2019; 9:20231. [PMID: 31882843 PMCID: PMC6934742 DOI: 10.1038/s41598-019-56643-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/16/2019] [Indexed: 11/10/2022] Open
Abstract
We investigated the cardiovascular effects of venoms from seven medically important species of snakes: Australian Eastern Brown snake (Pseudonaja textilis), Sri Lankan Russell’s viper (Daboia russelii), Javanese Russell’s viper (D. siamensis), Gaboon viper (Bitis gabonica), Uracoan rattlesnake (Crotalus vegrandis), Carpet viper (Echis ocellatus) and Puff adder (Bitis arietans), and identified two distinct patterns of effects: i.e. rapid cardiovascular collapse and prolonged hypotension. P. textilis (5 µg/kg, i.v.) and E. ocellatus (50 µg/kg, i.v.) venoms induced rapid (i.e. within 2 min) cardiovascular collapse in anaesthetised rats. P. textilis (20 mg/kg, i.m.) caused collapse within 10 min. D. russelii (100 µg/kg, i.v.) and D. siamensis (100 µg/kg, i.v.) venoms caused ‘prolonged hypotension’, characterised by a persistent decrease in blood pressure with recovery. D. russelii venom (50 mg/kg and 100 mg/kg, i.m.) also caused prolonged hypotension. A priming dose of P. textilis venom (2 µg/kg, i.v.) prevented collapse by E. ocellatus venom (50 µg/kg, i.v.), but had no significant effect on subsequent addition of D. russelii venom (1 mg/kg, i.v). Two priming doses (1 µg/kg, i.v.) of E. ocellatus venom prevented collapse by E. ocellatus venom (50 µg/kg, i.v.). B. gabonica, C. vegrandis and B. arietans (all at 200 µg/kg, i.v.) induced mild transient hypotension. Artificial respiration prevented D. russelii venom induced prolonged hypotension but not rapid cardiovascular collapse from E. ocellatus venom. D. russelii venom (0.001–1 μg/ml) caused concentration-dependent relaxation (EC50 = 82.2 ± 15.3 ng/ml, Rmax = 91 ± 1%) in pre-contracted mesenteric arteries. In contrast, E. ocellatus venom (1 µg/ml) only produced a maximum relaxant effect of 27 ± 14%, suggesting that rapid cardiovascular collapse is unlikely to be due to peripheral vasodilation. The prevention of rapid cardiovascular collapse, by ‘priming’ doses of venom, supports a role for depletable endogenous mediators in this phenomenon.
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Affiliation(s)
- Rahini Kakumanu
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Barbara K Kemp-Harper
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Anjana Silva
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.,Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, 50008, Sri Lanka
| | - Sanjaya Kuruppu
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.,Clinical Toxicology Research Group, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3168, Australia.
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Generation of antibodies against disintegrin and cysteine-rich domains by DNA immunization: An approach to neutralize snake venom-induced haemorrhage. Asian Pac J Trop Biomed 2017. [DOI: 10.1016/j.apjtb.2016.12.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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8
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Sánchez LV, Pla D, Herrera M, Chippaux JP, Calvete JJ, Gutiérrez JM. Evaluation of the preclinical efficacy of four antivenoms, distributed in sub-Saharan Africa, to neutralize the venom of the carpet viper, Echis ocellatus, from Mali, Cameroon, and Nigeria. Toxicon 2015; 106:97-107. [DOI: 10.1016/j.toxicon.2015.09.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/16/2015] [Accepted: 09/21/2015] [Indexed: 11/28/2022]
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Serine protease variants encoded by Echis ocellatus venom gland cDNA: cloning and sequencing analysis. J Biomed Biotechnol 2010; 2010. [PMID: 20936075 PMCID: PMC2949595 DOI: 10.1155/2010/134232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 07/20/2010] [Indexed: 11/26/2022] Open
Abstract
Envenoming by Echis saw-scaled viper is the leading cause of death and morbidity in Africa due to snake bite. Despite its medical importance, there have been few investigations into the toxin composition of the venom of this viper. Here, we report the cloning of cDNA sequences encoding four groups or isoforms of the haemostasis-disruptive Serine protease proteins (SPs) from the venom glands of Echis ocellatus. All these SP sequences encoded the cysteine residues scaffold that form the 6-disulphide bonds responsible for the characteristic tertiary structure of venom serine proteases. All the Echis ocellatus EoSP groups showed varying degrees of sequence similarity to published viper venom SPs. However, these groups also showed marked intercluster sequence conservation across them which were significantly different from that of previously published viper SPs. Because viper venom SPs exhibit a high degree of sequence similarity and yet exert profoundly different effects on the mammalian haemostatic system, no attempt was made to assign functionality to the new Echis ocellatus EoSPs on the basis of sequence alone. The extraordinary level of interspecific and intergeneric sequence conservation exhibited by the Echis ocellatus EoSPs and analogous serine proteases from other viper species leads us to speculate that antibodies to representative molecules should neutralise (that we will exploit, by epidermal DNA immunization) the biological function of this important group of venom toxins in vipers that are distributed throughout Africa, the Middle East, and the Indian subcontinent.
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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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11
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Reza A, Kini RM. PROTHROMBIN ACTIVATORS FROM AUSTRALIAN SNAKES. TOXIN REV 2008. [DOI: 10.1080/15569540600567313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Reza MA, Swarup S, Kini RM. Gene structures of trocarin D and coagulation factor X, two functionally diverse prothrombin activators from Australian rough scaled snake. PATHOPHYSIOLOGY OF HAEMOSTASIS AND THROMBOSIS 2006; 34:205-8. [PMID: 16707929 DOI: 10.1159/000092425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of prothrombin to thrombin is the key reaction in blood coagulation cascade. We have recently shown that Australian rough scaled snake, Tropidechis carinatus, possesses two parallel prothrombin activator systems. Trocarin D, a venom prothrombin activator produced in the venom gland, plays an offensive role as a toxin, whereas factor X is produced in the liver and plays a role in the hemostatic mechanism. These two proteins are structurally similar and have identical domain architecture. Because of the differences in their physiological roles, and tissue-specific expression, we determined the gene structure of these closely related proteins. Both the genes have eight exons similar to all mammalian factor X genes. All the exon-intron boundaries of these two genes are at the same position and the splice junctions are almost identical. Partial sequencing of the introns shows that they share a very high degree of sequence identity indicating that the gene duplication is a recent event. Further studies on the characterization of these two genes particularly the promoter regions are in progress.
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Affiliation(s)
- M Abu Reza
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
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13
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Wagstaff SC, Laing GD, Theakston RDG, Papaspyridis C, Harrison RA. Bioinformatics and multiepitope DNA immunization to design rational snake antivenom. PLoS Med 2006; 3:e184. [PMID: 16737347 PMCID: PMC1472699 DOI: 10.1371/journal.pmed.0030184] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 01/31/2006] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Snake venom is a potentially lethal and complex mixture of hundreds of functionally diverse proteins that are difficult to purify and hence difficult to characterize. These difficulties have inhibited the development of toxin-targeted therapy, and conventional antivenom is still generated from the sera of horses or sheep immunized with whole venom. Although life-saving, antivenoms contain an immunoglobulin pool of unknown antigen specificity and known redundancy, which necessitates the delivery of large volumes of heterologous immunoglobulin to the envenomed victim, thus increasing the risk of anaphylactoid and serum sickness adverse effects. Here we exploit recent molecular sequence analysis and DNA immunization tools to design more rational toxin-targeted antivenom. METHODS AND FINDINGS We developed a novel bioinformatic strategy that identified sequences encoding immunogenic and structurally significant epitopes from an expressed sequence tag database of a venom gland cDNA library of Echis ocellatus, the most medically important viper in Africa. Focusing upon snake venom metalloproteinases (SVMPs) that are responsible for the severe and frequently lethal hemorrhage in envenomed victims, we identified seven epitopes that we predicted would be represented in all isomers of this multimeric toxin and that we engineered into a single synthetic multiepitope DNA immunogen (epitope string). We compared the specificity and toxin-neutralizing efficacy of antiserum raised against the string to antisera raised against a single SVMP toxin (or domains) or antiserum raised by conventional (whole venom) immunization protocols. The SVMP string antiserum, as predicted in silico, contained antibody specificities to numerous SVMPs in E. ocellatus venom and venoms of several other African vipers. More significantly, the antiserum cross-specifically neutralized hemorrhage induced by E. ocellatus and Cerastes cerastes cerastes venoms. CONCLUSIONS These data provide valuable sequence and structure/function information of viper venom hemorrhagins but, more importantly, a new opportunity to design toxin-specific antivenoms-the first major conceptual change in antivenom design after more than a century of production. Furthermore, this approach may be adapted to immunotherapy design in other cases where targets are numerous, diverse, and poorly characterized such as those generated by hypermutation or antigenic variation.
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Affiliation(s)
- Simon C Wagstaff
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
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Ramos OHP, Selistre-de-Araujo HS. Snake venom metalloproteases--structure and function of catalytic and disintegrin domains. Comp Biochem Physiol C Toxicol Pharmacol 2006; 142:328-346. [PMID: 16434235 DOI: 10.1016/j.cbpc.2005.11.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 11/09/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
Snake venoms are relevant sources of toxins that have evolved towards the engineering of highly active compounds. In the last years, research efforts have produced great advance in their understanding and uses. Metalloproteases with disintegrin domains are among the most abundant toxins in many Viperidae snake venoms. This review will focus on the structure, function and possible applications of the metalloprotease and disintegrin domains.
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Affiliation(s)
- O H P Ramos
- Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, Rodovia Washington Luis, Km 235, São Carlos, SP, 13565-905, Brazil
| | - H S Selistre-de-Araujo
- Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, Rodovia Washington Luis, Km 235, São Carlos, SP, 13565-905, Brazil.
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15
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Laing GD, Compton SJ, Ramachandran R, Fuller GLJ, Wilkinson MC, Wagstaff SC, Watson SP, Kamiguti AS, Theakston RDG, Senis YA. Characterization of a novel protein from Proatheris superciliaris venom: proatherocytin, a 34-kDa platelet receptor PAR1 agonist. Toxicon 2006; 46:490-9. [PMID: 16112700 DOI: 10.1016/j.toxicon.2005.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Revised: 06/07/2005] [Accepted: 06/08/2005] [Indexed: 11/28/2022]
Abstract
Many toxins from viperid venoms have been characterised as powerful activators of platelets. Here, the venom from the East African Lowland viper, Proatheris superciliaris, was investigated for its effect on platelets and the coagulation system. Whole P. superciliaris venom stimulated platelet shape change and aggregation; however, the stimulation of platelet activation was unaffected by the structurally distinct Src family kinase inhibitors PP1 and PD0173952, suggesting that platelet activation was mediated by a G protein-coupled receptor. A platelet reactive 34-kDa protein was isolated from P. superciliaris venom which we have designated proatherocytin. This protein induced Src kinase-independent aggregation of both human and mouse platelets that was inhibited by the serine protease inhibitor AEBSF. Proatherocytin did not clot bovine or human fibrinogen, degrade fibrinogen or hydrolyse the serine protease substrate benzoyl-FVR-pNA. It activated human PAR1 on stably transfected rat kidney epithelial cells, whereas no activation of the trypsin receptor PAR2 was shown. Surprisingly, Edman degradation of proatherocytin revealed sequence identity with existing disintegrin-like domains of snake venom metalloproteinases. These results suggest that proatherocytin is a highly selective PAR1 agonist that also causes mouse platelet aggregation, probably through cleavage of PAR4.
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Affiliation(s)
- Gavin D Laing
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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Howes JM, Kamiguti AS, Theakston RDG, Wilkinson MC, Laing GD. Effects of three novel metalloproteinases from the venom of the West African saw-scaled viper, Echis ocellatus on blood coagulation and platelets. Biochim Biophys Acta Gen Subj 2005; 1724:194-202. [PMID: 15863354 DOI: 10.1016/j.bbagen.2005.03.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 03/11/2005] [Accepted: 03/18/2005] [Indexed: 11/30/2022]
Abstract
Two metalloproteinases, a 24-kDa P-I EoVMP1 and a 56-kDa P-III EoVMP2, have recently been isolated from the venom of the West African saw-scaled viper Echis ocellatus. We now reveal a new 65-kDa haemorrhagic group P-III metalloproteinase which we have designated EoVMP3. The aim of this study was to determine whether these three snake venom metalloproteinases (SVMPs) affect platelets and blood coagulation. EoVMP1 had no effect on the aggregation of washed human platelets, whereas EoVMP2 inhibited collagen-induced platelet aggregation. In contrast, EoVMP3 did not inhibit the aggregation of platelets by collagen but instead activated platelets in the absence of any additional co-factors. All three SVMPs were capable of activating prothrombin to varying degrees and can therefore be described as procoagulants. EoVMP1, EoVMP2 and EoVMP3 share sequence identity with other members of the reprolysin family, but differ greatly in their effects on some of the components that control haemostasis.
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Affiliation(s)
- J-M Howes
- Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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17
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Modesto JCDA, Junqueira-de-Azevedo ILM, Neves-Ferreira AGC, Fritzen M, Oliva MLV, Ho PL, Perales J, Chudzinski-Tavassi AM. Insularinase A, a prothrombin activator from Bothrops insularis venom, is a metalloprotease derived from a gene encoding protease and disintegrin domains. Biol Chem 2005; 386:589-600. [PMID: 16006246 DOI: 10.1515/bc.2005.069] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The first low-molecular-mass metalloprotease presenting prothrombin activating activity was purified from Bothrops insularis venom and named insularinase A. It is a single-chain protease with a molecular mass of 22 639 Da. cDNA sequence analysis revealed that the disintegrin domain of the precursor protein is post-translationally processed, producing the mature insularinase A. Analysis of its deduced amino acid sequence showed a high similarity with several fibrin(ogen)olytic metalloproteases and only a moderate similarity with prothrombin activators. However, SDS-PAGE of prothrombin after activation by insularinase A showed fragment patterns similar to those generated by group A prothrombin activators, which convert prothrombin into meizothrombin independently of the prothrombinase complex. In addition, insularinase A activates factor X and hydrolyses fibrinogen and fibrin. Chelating agents fully inhibit all insularinase A activities. Insularinase A induced neither detachment nor apoptosis of human endothelial cells and was also not able to trigger an endothelial proinflammatory cell response. Nitric oxide and prostacyclin levels released by endothelial cells were significantly increased after treatment with insularinase A. Our results show that, although its primary structure is related to class P-I fibrin(ogen)olytic metalloproteases, insularinase A is functionally similar to group A prothrombin activators.
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Hasson SS, Theakston RDG, Harrison RA. Antibody zymography: a novel adaptation of zymography to determine the protease-neutralising potential of specific antibodies and snake antivenoms. J Immunol Methods 2004; 292:131-9. [PMID: 15350518 DOI: 10.1016/j.jim.2004.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Revised: 04/15/2004] [Accepted: 06/10/2004] [Indexed: 11/29/2022]
Abstract
A common problem in the development of antibody-based therapeutics is the selection, usually from a large population, of specific antibodies with the desired function. One of our research objectives is to identify antibodies capable of neutralising the most important haemorrhagic and haemostasis-disruptive proteases from viper venom. Here, we describe a modification of conventional gelatin-zymography that permits the identification of antibodies capable of neutralising gelatinolytic proteases. We demonstrate that the gelatinolytic activity of viper venom proteases is neutralised by addition of viper antivenom to the matrix of conventional gelatin-zymograms. Venom protein gelatinolytic activity was unaffected by inclusion of antibody from control, non-immunised animals or immunoglobulin-depleted serum. The application of this antibody zymogram technique for future research on snake venoms is evaluated in the context of identified limitations.
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Affiliation(s)
- S S Hasson
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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19
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Harrison RA. Development of venom toxin-specific antibodies by DNA immunisation: rationale and strategies to improve therapy of viper envenoming. Vaccine 2004; 22:1648-55. [PMID: 15068847 DOI: 10.1016/j.vaccine.2003.09.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
DNA vaccination induces potent cellular immune responses against infectious and parasitic intracellular pathogens. This paper illustrates that DNA immunisation protocols can be adapted to induce high titre antibody responses with potential to improve the treatment of systemic snake envenoming that kills 20000 people annually in Africa. Envenoming by the saw-scaled vipers and puff adders are responsible for the majority of these deaths. DNA sequences encoding haemorrhagic, pro- and anti-coagulant and other haemostasis-disruptive venom toxins from these vipers showed extensive cross-specific and cross-generic sequence and structural similarities. The predicted antigenic profiles of these toxin sequences are utilised to design DNA immunisation constructs to generate toxin-specific antibodies with potential to polyspecifically neutralise venoms from the most medically-important African vipers.
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Affiliation(s)
- R A Harrison
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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