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Gilliam LL, Gilliam J, Samuel SP, Carter RW, Ritchey J, Bulfone T, Gutiérrez JM, Williams DJ, Durkin DM, Stephens SI, Lewin MR. Oral and IV Varespladib Rescue Experiments in Juvenile Pigs with Weakness Induced by Australian and Papuan Oxyuranus scutellatus Venoms. Toxins (Basel) 2023; 15:557. [PMID: 37755983 PMCID: PMC10537020 DOI: 10.3390/toxins15090557] [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: 06/08/2023] [Revised: 08/02/2023] [Accepted: 08/17/2023] [Indexed: 09/28/2023] Open
Abstract
Antivenom is currently the standard-of-care treatment for snakebite envenoming, but its efficacy is limited by treatment delays, availability, and in many cases, species specificity. Many of the rapidly lethal effects of envenoming are caused by venom-derived toxins, such as phospholipase A2 (sPLA2); therefore, small molecule direct toxin inhibitors targeting these toxins may have utility as initial and adjunct therapies after envenoming. Varespladib (intravenous, IV) and varespladib-methyl (oral) have been shown to potently inhibit sPLA2s from snake venoms in murine and porcine models, thus supporting their further study as potential treatments for snakebite envenoming. In this pilot study, we tested the ability of these compounds to reverse neurotoxic effects of venom from the Australian and Papuan taipan (Oxyuranus scutellatus) subspecies in juvenile pigs (Sus domesticus). The mean survival time for control animals receiving Australian taipan venom (0.03 mg/kg, n = 3) was 331 min ± 15 min; for those receiving Papuan taipan venom (0.15 mg/kg, n = 3) it was 178 ± 31 min. Thirteen pigs received Australian taipan venom and treatment with either IV or oral varespladib (or with IV to oral transition) and all 13 survived the duration of the study (≥96 h). Eight pigs received Papuan taipan venom followed by treatment: Briefly: Two animals received antivenom immediately and survived to the end of the study. Two animals received antivenom treatment delayed 45 min from envenoming and died within 4 h. Two animals received similarly delayed antivenom treatment and were rescued by varespladib. Two animals were treated with varespladib alone after a 45-min delay. Treatment with varespladib only was effective but required repeat dosing over the course of the study. Findings highlight both the importance of early treatment and, as well, a half-life for the investigational inhibitors now in Phase II clinical trials for snakebite. Varespladib rapidly reversed weakness even when administered many hours post-envenoming and, overall, our results suggest that varespladib and varespladib-methyl could be efficacious tools in the treatment of sPLA2-induced weakness from Oxyuranus envenoming. Further clinical study as initial therapy and as potential method of rescue from some types of antivenom-resistant envenomings are supported by these data.
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Affiliation(s)
- Lyndi L. Gilliam
- Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA; (L.L.G.); (J.G.); (J.R.)
| | - John Gilliam
- Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA; (L.L.G.); (J.G.); (J.R.)
| | - Stephen P. Samuel
- Division of Research Ophirex, Inc., Corte Madera, CA 94925, USA; (S.P.S.); (R.W.C.); (S.I.S.)
| | - Rebecca W. Carter
- Division of Research Ophirex, Inc., Corte Madera, CA 94925, USA; (S.P.S.); (R.W.C.); (S.I.S.)
| | - Jerry Ritchey
- Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA; (L.L.G.); (J.G.); (J.R.)
| | - Tommaso Bulfone
- Center for Exploration and Travel Health, California Academy of Sciences, San Francisco, CA 94118, USA; (T.B.)
- School of Medicine, University of California, San Francisco, CA 94143, USA
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
| | - David J. Williams
- Regulation and Prequalification Department (RPQ) at the World Health Organization (WHO), 1211 Geneva, Switzerland;
| | - Daniela M. Durkin
- Center for Exploration and Travel Health, California Academy of Sciences, San Francisco, CA 94118, USA; (T.B.)
| | - Sally I. Stephens
- Division of Research Ophirex, Inc., Corte Madera, CA 94925, USA; (S.P.S.); (R.W.C.); (S.I.S.)
| | - Matthew R. Lewin
- Division of Research Ophirex, Inc., Corte Madera, CA 94925, USA; (S.P.S.); (R.W.C.); (S.I.S.)
- Center for Exploration and Travel Health, California Academy of Sciences, San Francisco, CA 94118, USA; (T.B.)
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Madhushani U, Isbister GK, Tasoulis T, Hodgson WC, Silva A. In-Vitro Neutralization of the Neurotoxicity of Coastal Taipan Venom by Australian Polyvalent Antivenom: The Window of Opportunity. Toxins (Basel) 2020; 12:toxins12110690. [PMID: 33142783 PMCID: PMC7694127 DOI: 10.3390/toxins12110690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 12/17/2022] Open
Abstract
Coastal taipan (Oxyuranus scutellatus) envenoming causes life-threatening neuromuscular paralysis in humans. We studied the time period during which antivenom remains effective in preventing and arresting in vitro neuromuscular block caused by taipan venom and taipoxin. Venom showed predominant pre-synaptic neurotoxicity at 3 µg/mL and post-synaptic neurotoxicity at 10 µg/mL. Pre-synaptic neurotoxicity was prevented by addition of Australian polyvalent antivenom before the venom and taipoxin and, reversed when antivenom was added 5 min after venom and taipoxin. Antivenom only partially reversed the neurotoxicity when added 15 min after venom and had no significant effect when added 30 min after venom. In contrast, post-synaptic activity was fully reversed when antivenom was added 30 min after venom. The effect of antivenom on pre-synaptic neuromuscular block was reproduced by washing the bath at similar time intervals for 3 µg/mL, but not for 10 µg/mL. We found an approximate 10–15 min time window in which antivenom can prevent pre-synaptic neuromuscular block. This time window is likely to be longer in envenomed patients due to the delay in venom absorption. Similar effectiveness of antivenom and washing with 3 µg/mL venom suggests that antivenom most likely acts by neutralizing pre-synaptic toxins before they interfere with neurotransmission inside the motor nerve terminals.
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Affiliation(s)
- Umesha Madhushani
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka;
| | - Geoffrey K. Isbister
- Clinical Toxicology Research Group, University of Newcastle, Callaghan 2308, Australia; (G.K.I.); (T.T.)
| | - Theo Tasoulis
- Clinical Toxicology Research Group, University of Newcastle, Callaghan 2308, Australia; (G.K.I.); (T.T.)
| | - Wayne C. Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton 3800, Australia;
| | - Anjana Silva
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka;
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton 3800, Australia;
- Correspondence:
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Fontana Oliveira IC, Gutiérrez JM, Lewin MR, Oshima-Franco Y. Varespladib (LY315920) inhibits neuromuscular blockade induced by Oxyuranus scutellatus venom in a nerve-muscle preparation. Toxicon 2020; 187:101-104. [PMID: 32889027 DOI: 10.1016/j.toxicon.2020.08.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/08/2020] [Accepted: 08/30/2020] [Indexed: 11/28/2022]
Abstract
The phospholipase A2 (PLA2) inhibitors varespladib (LY315920) and its orally available derivative methyl-varespladib (LY333013) have been proposed as potential therapies for the treatment of snakebite envenomings in which toxicity depends on the action of PLA2s. In this study, the ability of LY315920 to abrogate the effect of the potent neurotoxic venom of Oxyuranus scutellatus (taipan) was assessed using the mouse phrenic nerve-diaphragm preparation. LY315920 inhibited the venom when (a) incubated with venom before addition to the medium; (b) added to the medium before addition of venom, and; (c) added to the medium within 30 min after addition of venom, and even after the onset of decline in twitch response. This contrasts with previous results with antivenom using the same experimental model, in which the window of time when antibodies are effective is shorter than 10 min. It is proposed that such differences may depend either on the higher affinity of the inhibitor for PLA2s or on the possibility that LY315920 reaches the cytosol of the nerve terminals, inhibiting neurotoxins that have been internalized. Our findings bear implications on the therapeutic potential of varespladib in neurotoxic snakebite envenomings mediated by presynaptically-acting PLA2s.
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Affiliation(s)
- Isadora Caruso Fontana Oliveira
- Post-Graduate Program in Pharmaceutical Sciences, University of Sorocaba (UNISO), Rodovia Raposo Tavares Km 92.5, 18023-000, Sorocaba, SP, Brazil
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Matthew R Lewin
- California Academy of Sciences, San Francisco, CA, 94118, USA; Ophirex, Inc., Corte Madera, CA, 94925, USA
| | - Yoko Oshima-Franco
- Post-Graduate Program in Pharmaceutical Sciences, University of Sorocaba (UNISO), Rodovia Raposo Tavares Km 92.5, 18023-000, Sorocaba, SP, Brazil.
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Tasoulis T, Silva A, Veerati PC, Baker M, Hodgson WC, Dunstan N, Isbister GK. Intra-Specific Venom Variation in the Australian Coastal Taipan Oxyuranus scutellatus. Toxins (Basel) 2020; 12:toxins12080485. [PMID: 32751571 PMCID: PMC7472000 DOI: 10.3390/toxins12080485] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/13/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Intra-specific venom variation has the potential to provide important insights into the evolution of snake venom, but remains a relatively neglected aspect of snake venom studies. We investigated the venom from 13 individual coastal taipans Oxyuranus scutellatus from four localities on the north-east coast of Australia, spanning a distance of 2000 km. The intra-specific variation in taipan venom was considerably less than the inter-specific variation between it and the other Australian elapids to which it was compared. The electrophoretic venom profile of O. scutellatus was visually different to six other genera of Australian elapids, but not to its congener inland taipan O. microlepidotus. There was minimal geographical variation in taipan venom, as the intra-population variation exceeded the inter-population variation for enzymatic activity, procoagulant activity, and the abundance of neurotoxins. The pre-synaptic neurotoxin (taipoxin) was more abundant than the post-synaptic neurotoxins (3FTx), with a median of 11.0% (interquartile range (IQR): 9.7% to 18.3%; range: 6.7% to 23.6%) vs. a median of 3.4% (IQR: 0.4% to 6.7%; range: 0% to 8.1%). Three taipan individuals almost completely lacked post-synaptic neurotoxins, which was not associated with geography and occurred within two populations. We found no evidence of sexual dimorphism in taipan venom. Our study provides a basis for evaluating the significance of intra-specific venom variation within a phylogenetic context by comparing it to the inter-specific and inter-generic variation. The considerable intra-population variation we observed supports the use of several unpooled individuals from each population when making inter-specific comparisons.
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Affiliation(s)
- Theo Tasoulis
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW 2308, Australia; (P.C.V.); (G.K.I.)
- Correspondence:
| | - Anjana Silva
- Monash Venom Group, Monash University, Clayton, VIC 3800, Australia; (A.S.); (W.C.H.)
- Faculty of Medicine and Allied Sciences, Rajarata University, Anuradhapura-Rambewa Hwy, Anuradhapura 50008, Sri Lanka
| | - Punnam Chander Veerati
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW 2308, Australia; (P.C.V.); (G.K.I.)
| | - Mark Baker
- Priority Research Centre in Reproductive Biology, University of Newcastle, Newcastle, NSW 2308, Australia;
| | - Wayne C. Hodgson
- Monash Venom Group, Monash University, Clayton, VIC 3800, Australia; (A.S.); (W.C.H.)
| | | | - Geoffrey K. Isbister
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW 2308, Australia; (P.C.V.); (G.K.I.)
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Liang Q, Huynh TM, Isbister GK, Hodgson WC. Isolation and pharmacological characterization of α-Elapitoxin-Na1a, a novel short-chain postsynaptic neurotoxin from the venom of the Chinese Cobra (Naja atra). Biochem Pharmacol 2020; 181:114059. [PMID: 32473162 DOI: 10.1016/j.bcp.2020.114059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/25/2020] [Indexed: 11/27/2022]
Abstract
The Chinese Cobra (Naja atra) is an elapid snake of major medical importance in southern China. Although previous studies have shown that postsynaptic neurotoxins account for 11-23% of N. atra venom, envenomed patients do not display marked signs of neurotoxicity. We have previously shown that the lack of clinical neurotoxicity following snake envenoming by some species with 'neurotoxic' venoms may be related to the high prevalence of short-chain postsynaptic neurotoxins in these venoms. In this study, we describe the isolation and characterization of α-Elapitoxin-Na1a (α-EPTX-Na1a; 6949 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 9% of N. atra crude venom. α-EPTX-Na1a (30-300 nM) produced concentration-dependent inhibition of indirect-twitches, with a t90 value of 17 ± 2 min at 300 nM, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The prior addition of either Chinese N. atra monovalent antivenom (0.3 U/ml) or Australian polyvalent snake antivenom (2.4 U/ml), prevented the in vitro neurotoxic effects of α-EPTX-Na1a (30 nM). Addition of each of these antivenoms at the t90 time point partially reversed the in vitro neurotoxicity caused by α-EPTX-Na1a (30 nM). The inhibition of indirect twitches by α-EPTX-Na1a (30 nM) was not reversed by repeatedly washing the tissue. α-EPTX-Na1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.21. De novo protein sequencing of α-EPTX-Na1a revealed a typical short-chain postsynaptic neurotoxin profile of 62 amino acids which shared >98% amino acid sequence similarity with short-chain postsynaptic neurotoxins from other Naja species. When compared to short-chain neurotoxins isolated from cobras in China, α-EPTX-Na1a contained novel residues K47Q (i.e. lysine to glutamine), N48T (i.e. asparagine to threonine) and G49A (i.e. glycine to alanine). In conclusion, α-EPTX-Na1a is a potent, pseudo-irreversible, short-chain neurotoxin. The high prevalence of α-EPTX-Na1a in Chinese N. atra venom is likely to explain the mild neurotoxicity experienced by envenomed patients.
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Affiliation(s)
- Qing Liang
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University, 151 Yanjiang Rd, Guangzhou 510120, Guangdong, PR China
| | - Tam M Huynh
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Clinical Toxicology Research Group, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
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Albulescu LO, Kazandjian T, Slagboom J, Bruyneel B, Ainsworth S, Alsolaiss J, Wagstaff SC, Whiteley G, Harrison RA, Ulens C, Kool J, Casewell NR. A Decoy-Receptor Approach Using Nicotinic Acetylcholine Receptor Mimics Reveals Their Potential as Novel Therapeutics Against Neurotoxic Snakebite. Front Pharmacol 2019; 10:848. [PMID: 31417406 PMCID: PMC6683245 DOI: 10.3389/fphar.2019.00848] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/02/2019] [Indexed: 12/24/2022] Open
Abstract
Snakebite is a neglected tropical disease that causes 138,000 deaths each year. Neurotoxic snake venoms contain small neurotoxins, including three-finger toxins (3FTxs), which can cause rapid paralysis in snakebite victims by blocking postsynaptic transmission via nicotinic acetylcholine receptors (nAChRs). These toxins are typically weakly immunogenic and thus are often not effectively targeted by current polyclonal antivenom therapies. We investigated whether nAChR mimics, also known as acetylcholine binding proteins (AChBPs), could effectively capture 3FTxs and therefore be developed as a novel class of snake-generic therapeutics for combatting neurotoxic envenoming. First, we identified the binding specificities of 3FTx from various medically important elapid snake venoms to nAChR using two recombinant nAChR mimics: the AChBP from Lymnaea stagnalis and a humanized neuronal α7 version (α7-AChBP). We next characterized these AChBP-bound and unbound fractions using SDS-PAGE and mass spectrometry. Interestingly, both mimics effectively captured long-chain 3FTxs from multiple snake species but largely failed to capture the highly related short-chain 3FTxs, suggesting a high level of binding specificity. We next investigated whether nAChR mimics could be used as snakebite therapeutics. We showed that while α7-AChBP alone did not protect against Naja haje (Egyptian cobra) venom lethality in vivo, it significantly prolonged survival times when coadministered with a nonprotective dose of antivenom. Thus, nAChR mimics are capable of neutralizing specific venom toxins and may be useful adjunct therapeutics for improving the safety and affordability of existing snakebite treatments by reducing therapeutic doses. Our findings justify exploring the future development of AChBPs as potential snakebite treatments.
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Affiliation(s)
- Laura-Oana Albulescu
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Taline Kazandjian
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Julien Slagboom
- AIMMS Division of BioMolecular Analysis, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Ben Bruyneel
- AIMMS Division of BioMolecular Analysis, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Stuart Ainsworth
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jaffer Alsolaiss
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Simon C Wagstaff
- Bioinformatics Unit, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Gareth Whiteley
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Robert A Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Jeroen Kool
- AIMMS Division of BioMolecular Analysis, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Ayvazyan NM, O'Leary VB, Dolly JO, Ovsepian SV. Neurobiology and therapeutic utility of neurotoxins targeting postsynaptic mechanisms of neuromuscular transmission. Drug Discov Today 2019; 24:1968-1984. [PMID: 31247153 DOI: 10.1016/j.drudis.2019.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/15/2019] [Accepted: 06/17/2019] [Indexed: 11/28/2022]
Abstract
The neuromuscular junction (NMJ) is the principal site for the translation of motor neurochemical signals to muscle activity. Therefore, the release and sensing machinery of acetylcholine (ACh) along with muscle contraction are two of the main targets of natural toxins and pathogens, causing paralysis. Given pharmacology and medical advances, the active ingredients of toxins that target postsynaptic mechanisms have become of major interest, showing promise as drug leads. Herein, we review key facets of prevalent toxins modulating the mechanisms of ACh sensing and generation of the postsynaptic response, with muscle contraction. We consider the correlation between their outstanding selectivity and potency plus effects on motor function, and discuss emerging data advocating their usage for the development of therapies alleviating neuromuscular dysfunction.
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Affiliation(s)
- Naira M Ayvazyan
- Orbeli Institute of Physiology, National Academy of Sciences of the Republic of Armenia, Yerevan, Armenia.
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Ruská 87, 100 00, Praha 10, Czech Republic
| | - J Oliver Dolly
- International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland
| | - Saak V Ovsepian
- International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland; The National Institute of Mental Health, Topolová 748, Klecany, Czech Republic; Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Ruská 87, 100 00, Praha 10, Czech Republic.
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A Review and Database of Snake Venom Proteomes. Toxins (Basel) 2017; 9:toxins9090290. [PMID: 28927001 PMCID: PMC5618223 DOI: 10.3390/toxins9090290] [Citation(s) in RCA: 349] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 12/15/2022] Open
Abstract
Advances in the last decade combining transcriptomics with established proteomics methods have made possible rapid identification and quantification of protein families in snake venoms. Although over 100 studies have been published, the value of this information is increased when it is collated, allowing rapid assimilation and evaluation of evolutionary trends, geographical variation, and possible medical implications. This review brings together all compositional studies of snake venom proteomes published in the last decade. Compositional studies were identified for 132 snake species: 42 from 360 (12%) Elapidae (elapids), 20 from 101 (20%) Viperinae (true vipers), 65 from 239 (27%) Crotalinae (pit vipers), and five species of non-front-fanged snakes. Approximately 90% of their total venom composition consisted of eight protein families for elapids, 11 protein families for viperines and ten protein families for crotalines. There were four dominant protein families: phospholipase A2s (the most common across all front-fanged snakes), metalloproteases, serine proteases and three-finger toxins. There were six secondary protein families: cysteine-rich secretory proteins, l-amino acid oxidases, kunitz peptides, C-type lectins/snaclecs, disintegrins and natriuretic peptides. Elapid venoms contained mostly three-finger toxins and phospholipase A2s and viper venoms metalloproteases, phospholipase A2s and serine proteases. Although 63 protein families were identified, more than half were present in <5% of snake species studied and always in low abundance. The importance of these minor component proteins remains unknown.
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Johnston CI, Ryan NM, O'Leary MA, Brown SGA, Isbister GK. Australian taipan (Oxyuranus spp.) envenoming: clinical effects and potential benefits of early antivenom therapy - Australian Snakebite Project (ASP-25). Clin Toxicol (Phila) 2016; 55:115-122. [PMID: 27903075 DOI: 10.1080/15563650.2016.1250903] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
CONTEXT Taipans (Oxyuranus spp.) are medically important venomous snakes from Australia and Papua New Guinea. The objective of this study was to describe taipan envenoming in Australian and its response to antivenom. METHODS Confirmed taipan bites were recruited from the Australian Snakebite Project. Data were collected prospectively on all snakebites, including patient demographics, bite circumstances, clinical effects, laboratory results, complications and treatment. Blood samples were taken and analysed by venom specific immunoassay to confirm snake species and measure venom concentration pre- and post-antivenom. RESULTS There were 40 confirmed taipan bites: median age 41 years (2-85 years), 34 were males and 21 were snake handlers. Systemic envenoming occurred in 33 patients with neurotoxicity (26), complete venom induced consumption coagulopathy (VICC) (16), partial VICC (15), acute kidney injury (13), myotoxicity (11) and thrombocytopenia (7). Venom allergy occurred in seven patients, three of which had no evidence of envenoming and one died. Antivenom was given to 34 patients with a median initial dose of one vial (range 1-4), and a median total dose of two vials (range 1-9). A greater total antivenom dose was associated with VICC, neurotoxicity and acute kidney injury. Early antivenom administration was associated with a decreased frequency of neurotoxicity, acute kidney injury, myotoxicity and intubation. There was a shorter median time to discharge of 51 h (19-432 h) in patients given antivenom <4 h post-bite, compared to 175 h (27-1104 h) in those given antivenom >4 h. Median peak venom concentration in 25 patients with systemic envenoming and a sample available was 8.4 ng/L (1-3212 ng/L). No venom was detected in post-antivenom samples, including 20 patients given one vial initially and five patients bitten by inland taipans. DISCUSSION Australian taipan envenoming is characterised by neurotoxicity, myotoxicity, coagulopathy, acute kidney injury and thrombocytopenia. One vial of antivenom binds all measurable venom and early antivenom was associated with a favourable outcome.
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Affiliation(s)
| | - Nicole M Ryan
- a Clinical Toxicology Research Group, University of Newcastle , Newcastle , Australia
| | - Margaret A O'Leary
- a Clinical Toxicology Research Group, University of Newcastle , Newcastle , Australia
| | - Simon G A Brown
- b Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Royal Perth Hospital and the University of Western Australia , Perth , Australia
| | - Geoffrey K Isbister
- a Clinical Toxicology Research Group, University of Newcastle , Newcastle , Australia.,c Department of Clinical Toxicology and Pharmacology , Calvary Mater Newcastle , Newcastle , Australia
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10
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Silva A, Hodgson WC, Isbister GK. Cross-Neutralisation of In Vitro Neurotoxicity of Asian and Australian Snake Neurotoxins and Venoms by Different Antivenoms. Toxins (Basel) 2016; 8:toxins8100302. [PMID: 27763543 PMCID: PMC5086662 DOI: 10.3390/toxins8100302] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/22/2016] [Accepted: 10/01/2016] [Indexed: 01/30/2023] Open
Abstract
There is limited information on the cross-neutralisation of neurotoxic venoms with antivenoms. Cross-neutralisation of the in vitro neurotoxicity of four Asian and four Australian snake venoms, four post-synaptic neurotoxins (α-bungarotoxin, α-elapitoxin-Nk2a, α-elapitoxin-Ppr1 and α-scutoxin; 100 nM) and one pre-synaptic neurotoxin (taipoxin; 100 nM) was studied with five antivenoms: Thai cobra antivenom (TCAV), death adder antivenom (DAAV), Thai neuro polyvalent antivenom (TNPAV), Indian Polyvalent antivenom (IPAV) and Australian polyvalent antivenom (APAV). The chick biventer cervicis nerve-muscle preparation was used for this study. Antivenom was added to the organ bath 20 min prior to venom. Pre- and post-synaptic neurotoxicity of Bungarus caeruleus and Bungarus fasciatus venoms was neutralised by all antivenoms except TCAV, which did not neutralise pre-synaptic activity. Post-synaptic neurotoxicity of Ophiophagus hannah was neutralised by all antivenoms, and Naja kaouthia by all antivenoms except IPAV. Pre- and post-synaptic neurotoxicity of Notechis scutatus was neutralised by all antivenoms, except TCAV, which only partially neutralised pre-synaptic activity. Pre- and post-synaptic neurotoxicity of Oxyuranus scutellatus was neutralised by TNPAV and APAV, but TCAV and IPAV only neutralised post-synaptic neurotoxicity. Post-synaptic neurotoxicity of Acanthophis antarcticus was neutralised by all antivenoms except IPAV. Pseudonaja textillis post-synaptic neurotoxicity was only neutralised by APAV. The α-neurotoxins were neutralised by TNPAV and APAV, and taipoxin by all antivenoms except IPAV. Antivenoms raised against venoms with post-synaptic neurotoxic activity (TCAV) cross-neutralised the post-synaptic activity of multiple snake venoms. Antivenoms raised against pre- and post-synaptic neurotoxic venoms (TNPAV, IPAV, APAV) cross-neutralised both activities of Asian and Australian venoms. While acknowledging the limitations of adding antivenom prior to venom in an in vitro preparation, cross-neutralization of neurotoxicity means that antivenoms from one region may be effective in other regions which do not have effective antivenoms. TCAV only neutralized post-synaptic neurotoxicity and is potentially useful in distinguishing pre-synaptic and post-synaptic effects in the chick biventer cervicis preparation.
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Affiliation(s)
- Anjana Silva
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
- Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura 50008, Sri Lanka.
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
| | - Geoffrey K Isbister
- Monash Venom Group, Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW 2298, Australia.
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Padula AM, Winkel KD. Antivenom production in the alpaca (Vicugna pacos): physiological and antibody responses to monovalent and polyvalent immunisation with Australian elapid venoms. Small Rumin Res 2016. [DOI: 10.1016/j.smallrumres.2016.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Barber CM, Rusmili MRA, Hodgson WC. Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis. Toxins (Basel) 2016; 8:toxins8030058. [PMID: 26938558 PMCID: PMC4810203 DOI: 10.3390/toxins8030058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 11/16/2022] Open
Abstract
Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins.
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Affiliation(s)
- Carmel M Barber
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton, VIC 3168, Australia.
| | - Muhamad Rusdi Ahmad Rusmili
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton, VIC 3168, Australia.
- Department of Basic Medical Sciences, Kulliyyah of Pharmacy, International Islamic University Malaysia, Bandar Indera Mahkota 23800, Malaysia.
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton, VIC 3168, Australia.
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13
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Herrera M, de Cássia de O Collaço R, Villalta M, Segura Á, Vargas M, Wright CE, Paiva OK, Matainaho T, Jensen SD, León G, Williams DJ, Rodrigues-Simioni L, Gutiérrez JM. Neutralization of the neuromuscular inhibition of venom and taipoxin from the taipan (Oxyuranus scutellatus) by F(ab')2 and whole IgG antivenoms. Toxicol Lett 2015; 241:175-83. [PMID: 26621539 DOI: 10.1016/j.toxlet.2015.11.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/05/2015] [Accepted: 11/21/2015] [Indexed: 11/25/2022]
Abstract
The neuromuscular junction activity of Oxyuranus scutellatus venom and its presynaptic neurotoxin, taipoxin, and their neutralization by two antivenoms were examined in mouse phrenic nerve-diaphragm preparations. The action of taipoxin was also studied at 21°C. The efficacy of the antivenoms was also assessed in an in vivo mouse model. Both antivenoms were effective in neutralizing the neuromuscular blocking activity in preincubation-type experiments. In experiments involving independent addition of venom and antivenoms, neutralization depended on the time interval between venom addition and antivenom application. When taipoxin was incubated for 5, 10 or 20min at 21°C, and antivenom added and temperature increased to 37°C, neutralization was achieved only when the toxin was incubated for 5 or 10min. The neutralization by the two antivenoms in an in vivo model showed that both whole IgG and F(ab')2 antivenoms were effective in neutralizing lethality. Our findings highlight the very rapid action of taipan venom at the nerve terminal, and the poor capacity of antivenoms to revert neurotoxicity as the time interval between venom or taipoxin application and antivenom addition increased. Additionally the disparity between molecular masses of the active substances of the two antivenoms did not result in differences in neutralization.
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Affiliation(s)
- María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Rita de Cássia de O Collaço
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Mauren Villalta
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Álvaro Segura
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Mariángela Vargas
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Christine E Wright
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Owen K Paiva
- Charles Campbell Toxinology Centre, School of Medicine & Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Teatulohi Matainaho
- Charles Campbell Toxinology Centre, School of Medicine & Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Simon D Jensen
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia; Charles Campbell Toxinology Centre, School of Medicine & Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Guillermo León
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - David J Williams
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia; Charles Campbell Toxinology Centre, School of Medicine & Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Léa Rodrigues-Simioni
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica.
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14
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Barber CM, Madaras F, Turnbull RK, Morley T, Dunstan N, Allen L, Kuchel T, Mirtschin P, Hodgson WC. Comparative studies of the venom of a new Taipan species, Oxyuranus temporalis, with other members of its genus. Toxins (Basel) 2014; 6:1979-95. [PMID: 24992081 PMCID: PMC4113736 DOI: 10.3390/toxins6071979] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 11/16/2022] Open
Abstract
Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified "profile" compared to other taipan venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans.
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Affiliation(s)
- Carmel M Barber
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria 3168, Australia.
| | - Frank Madaras
- Venom Science Pty Ltd, Tanunda, South Australia 5352, Australia.
| | - Richard K Turnbull
- SA Pathology, IMVS Veterinary Services, Gilles Plains, South Australia 5086, Australia.
| | - Terry Morley
- Adelaide Zoo, Adelaide, South Australia 5000, Australia.
| | - Nathan Dunstan
- Venom Supplies, Tanunda, South Australia, South Australia 5352, Australia.
| | - Luke Allen
- Venom Supplies, Tanunda, South Australia, South Australia 5352, Australia.
| | - Tim Kuchel
- SA Pathology, IMVS Veterinary Services, Gilles Plains, South Australia 5086, Australia.
| | - Peter Mirtschin
- Venom Science Pty Ltd, Tanunda, South Australia 5352, 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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15
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Rusmili MRA, Tee TY, Mustafa MR, Othman I, Hodgson WC. Isolation and characterization of α-elapitoxin-Bf1b, a postsynaptic neurotoxin from Malaysian Bungarus fasciatus venom. Biochem Pharmacol 2014; 88:229-36. [DOI: 10.1016/j.bcp.2014.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Muhamad Rusdi Ahmad Rusmili
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, 3168 Clayton, Victoria, Australia; Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, 46150 Bandar Sunway, Malaysia
| | - Ting Yee Tee
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, 46150 Bandar Sunway, Malaysia
| | - Mohd Rais Mustafa
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 59100 Kuala Lumpur, Malaysia
| | - Iekhsan Othman
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, 46150 Bandar Sunway, Malaysia
| | - Wayne C Hodgson
- Monash Venom Group, Department of Pharmacology, Faculty of Medicine, Nursing and Health Sciences, 3168 Clayton, Victoria, Australia.
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16
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Savanur A, Ali SA, Munir I, Abbasi A, Alam M, Shaikh HA. Pharmacological and biochemical studies on the venom of a clinically important viper snake (Echis carinatus) of Pakistan. Toxicon 2014; 80:47-57. [PMID: 24462660 DOI: 10.1016/j.toxicon.2014.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
Abstract
Echis carinatus (saw-scaled viper) has been the major culprit responsible for serious envenomation casualties throughout the subcontinent. The present study describes the electrophoretic and zymographic characterization of E. carinatus venom and its effect on mammalian smooth muscle. Crude venom showed the presence of disintegrin, PLA2, C-type lectin/lectin-like components, CRISP, Serine protease, l-amino acid oxidase and very high concentrations of SVMPs. E. carinatus venom (1, 10, 30, 50, 100 μg/ml) inhibited the active tension/force of muscle contraction in a time and concentration dependent manner. The observed effects abolished when the venom was heated at 100 °C for 5 min. However, a decrease in bath temperature from 37 °C to 26 °C or an increase in CaCl2 concentration to 5 mM did not prevent the inhibition of contractile activity. The contractile response elicited by exogenous application of 50 mM KCl and 1 μM acetylcholine (ACh) was also significantly inhibited by all venom concentrations. Prior administration of commercially available polyvalent anti-venom partially neutralized and prevented the effect of E. carinatus venom whereas addition of anti-venom at t50 failed to reverse the inhibitory effect. Studies on isolated intestinal muscle indicate involvement of myotoxic and apoptotic components in E. carinatus venom for irreversible damage to muscle tissue.
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Affiliation(s)
- Arifa Savanur
- Neuromuscular Research Unit, Department of Physiology, University of Karachi, Karachi 75270, Pakistan; H.E.J Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan
| | - Syed Abid Ali
- H.E.J Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan.
| | - Iqra Munir
- H.E.J Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan
| | - Atiya Abbasi
- H.E.J Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan
| | - Mehtab Alam
- H.E.J Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan
| | - Hilal Ahmed Shaikh
- Neuromuscular Research Unit, Department of Physiology, University of Karachi, Karachi 75270, Pakistan
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17
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Neuromuscular activity of Micrurus laticollaris (Squamata: Elapidae) venom in vitro. Toxins (Basel) 2014; 6:359-70. [PMID: 24445448 PMCID: PMC3920266 DOI: 10.3390/toxins6010359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 11/25/2022] Open
Abstract
In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake) venom (MLV) in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1–30 µg/mL) neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ± 11%, 53% ± 11%, 89% ± 5% and 89% ± 7% for one, three, 10 and 30 µg of venom/mL, respectively; n = 4; p < 0.05). In mouse phrenic nerve-diaphragm preparations, MLV (1–10 µg/mL) promoted a slight increase in the amplitude of twitch-tension (3 µg/mL), followed by neuromuscular blockade (n = 4); the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ± 3 min), without exhibiting a previous neuromuscular facilitation. The venom (3 µg/mL) induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs)/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ± 1.4 (basal) to 28 ± 2.5 (t15) and 12 ± 2 (t60)). The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 µg/mL) was also significantly less negative with MLV (10 µg/mL). Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities.
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18
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Hart AJ, Isbister GK, O’Donnell P, Williamson NA, Hodgson WC. Species differences in the neuromuscular activity of post-synaptic neurotoxins from two Australian black snakes (Pseudechis porphyriacus and Pseudechis colletti). Toxicol Lett 2013; 219:262-8. [DOI: 10.1016/j.toxlet.2013.03.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 11/27/2022]
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19
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Barber CM, Isbister GK, Hodgson WC. Alpha neurotoxins. Toxicon 2013; 66:47-58. [PMID: 23416229 DOI: 10.1016/j.toxicon.2013.01.019] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 01/29/2013] [Indexed: 10/27/2022]
Abstract
α-Neurotoxins have been isolated from hydrophid, elapid and, more recently, colubrid snake venoms. Also referred to as postsynaptic neurotoxins or 'curare mimetic' neurotoxins, they play an important role in the capture and/or killing of prey by binding to the nicotinic acetylcholine receptor on the skeletal muscle disrupting neurotransmission. They are also thought to cause respiratory paralysis in envenomed humans. This review will discuss the historical background into the discovery, isolation, structure and mechanism of action of the α-neurotoxins, including targets and cellular outcomes, and then will examine the potential uses of α-neurotoxins as pharmacological tools and/or as drug leads.
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Affiliation(s)
- Carmel M Barber
- Monash Venom Group, Department of Pharmacology, Monash University, Clayton, Victoria 3800, Australia
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20
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Pharmacological characterization of α-elapitoxin-Al2a from the venom of the Australian pygmy copperhead (Austrelaps labialis): An atypical long-chain α-neurotoxin with only weak affinity for α7 nicotinic receptors. Biochem Pharmacol 2012; 84:851-63. [DOI: 10.1016/j.bcp.2012.06.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 06/22/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022]
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21
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Kornhauser R, Isbister GK, O'Leary MA, Mirtschin P, Dunstan N, Hodgson WC. Cross-neutralisation of the neurotoxic effects of Egyptian cobra venom with commercial tiger snake antivenom. Basic Clin Pharmacol Toxicol 2012; 112:138-43. [PMID: 22788931 DOI: 10.1111/j.1742-7843.2012.00925.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/04/2012] [Indexed: 11/28/2022]
Abstract
Cross-neutralisation has been demonstrated for haemorrhagic venoms including Echis spp. and Cerastes spp. and for Australia elapid procoagulant toxins. A previous study showed that commercial tiger snake antivenom (TSAV) was able to neutralise the systemic effects of the Egyptian cobra, Naja haje, in vivo but it is unclear if this was true cross-neutralisation. The aim of the current study was to determine whether TSAV can neutralise the in vitro neurotoxic effects of N. haje venom. Both Notechis scutatus (10 μg/ml) and N. haje (10 μg/ml) venoms caused inhibition of indirect (supramaximal V, 0.1 Hz, 0.2 msec.) twitches of the chick biventer cervicis nerve-muscle preparation with t(90) values (i.e. the time to produce 90% inhibition of the original twitch height) of 26 ± 1 min. (n = 4) and 36 ± 4 min.; (n = 4). This effect at 10 μg/ml was significantly attenuated by the prior addition of TSAV (5 U/ml). A comparison of the reverse-phase HPLC profiles of both venoms showed some similarities with peak elution times, and SDS-PAGE analysis elucidated comparable bands across both venoms. Further analysis using Western immunoblotting indicated TSAV was able to detect N. haje venom, and enzyme immunoassay showed that in-house biotinylated polyclonal monovalent N. scutatus antibodies were able to detect N. haje venom. These findings demonstrate cross-neutralisation between different and geographically separated snakes supporting potential immunological similarities in snake toxin groups for a large range of snakes. This provides more evidence that antivenoms could be developed against specific toxin groups to cover a large range of snakes.
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Affiliation(s)
- Rachelle Kornhauser
- Department of Pharmacology, Monash Venom Group, Monash University, Clayton, Vic., Australia.
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22
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Barber CM, Isbister GK, Hodgson WC. Solving the 'Brown snake paradox': in vitro characterisation of Australasian snake presynaptic neurotoxin activity. Toxicol Lett 2012; 210:318-23. [PMID: 22343038 DOI: 10.1016/j.toxlet.2012.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/19/2022]
Abstract
Pseudonaja textilis (Eastern Brown snake) and Oxyuranus scutellatus scutellatus (Coastal taipan) are clinically important Australian elapid snakes, whose potent venoms contain the presynaptic (β) neurotoxins, textilotoxin and taipoxin, respectively, and a number of postsynaptic neurotoxins. However, while taipan envenoming frequently results in neurotoxicity, Brown snake envenoming causes an isolated coagulopathy and neurotoxicity is rare. This phenomenon is called the 'Brown snake paradox'. This study compared the pharmacology of both venoms and their respective presynaptic neurotoxins to investigate this phenomenon. From size-exclusion high performance liquid chromatography (HPLC) analysis textilotoxin represents a significantly smaller proportion (5.7%) of P. textilis venom compared to taipoxin in O. s. scutellatus venom (20.4%). In the chick biventer cervicis nerve-muscle (CBCNM) preparation both venoms caused concentration-dependent neurotoxicity, with P. textilis venom being significantly more potent than O. s. scutellatus venom. Conversely, taipoxin was significantly more potent than textilotoxin when compared at the same concentration. Textilotoxin only partially contributed to the overall neurotoxicity of P. textilis venom, while taipoxin accounted for the majority of the neurotoxicity of O. s. scutellatus venom in the CBCNM preparation. Compared with taipoxin, textilotoxin is less potent and constitutes a smaller proportion of the venom. This is likely to be the reason for the absence of neurotoxicity in envenomed humans thus explaining the 'Brown snake paradox'.
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Affiliation(s)
- Carmel M Barber
- Monash Venom Group, Department of Pharmacology, Monash University, Victoria, Australia
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23
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Herrera M, Fernández J, Vargas M, Villalta M, Segura Á, León G, Angulo Y, Paiva O, Matainaho T, Jensen SD, Winkel KD, Calvete JJ, Williams DJ, Gutiérrez JM. Comparative proteomic analysis of the venom of the taipan snake, Oxyuranus scutellatus, from Papua New Guinea and Australia: role of neurotoxic and procoagulant effects in venom toxicity. J Proteomics 2012; 75:2128-40. [PMID: 22266484 DOI: 10.1016/j.jprot.2012.01.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 12/26/2011] [Accepted: 01/08/2012] [Indexed: 11/18/2022]
Abstract
The venom proteomes of populations of the highly venomous taipan snake, Oxyuranus scutellatus, from Australia and Papua New Guinea (PNG), were characterized by reverse-phase HPLC fractionation, followed by analysis of chromatographic fractions by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of tryptic peptides. Proteins belonging to the following seven protein families were identified in the two venoms: phospholipase A(2) (PLA(2)), Kunitz-type inhibitor, metalloproteinase (SVMP), three-finger toxin (3FTx), serine proteinase, cysteine-rich secretory proteins (CRISP), and coagulation factor V-like protein. In addition, C-type lectin/lectin-like protein and venom natriuretic peptide were identified in the venom of specimens from PNG. PLA(2)s comprised more than 65% of the venoms of these two populations. Antivenoms generated against the venoms of these populations showed a pattern of cross-neutralization, corroborating the immunological kinship of these venoms. Toxicity experiments performed in mice suggest that, at low venom doses, neurotoxicity leading to respiratory paralysis represents the predominant mechanism of prey immobilization and death. However, at high doses, such as those injected in natural bites, intravascular thrombosis due to the action of the prothrombin activator may constitute a potent and very rapid mechanism for killing prey.
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Affiliation(s)
- María Herrera
- Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica
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Vargas M, Segura A, Herrera M, Villalta M, Estrada R, Cerdas M, Paiva O, Matainaho T, Jensen SD, Winkel KD, León G, Gutiérrez JM, Williams DJ. Preclinical evaluation of caprylic acid-fractionated IgG antivenom for the treatment of Taipan (Oxyuranus scutellatus) envenoming in Papua New Guinea. PLoS Negl Trop Dis 2011; 5:e1144. [PMID: 21610854 PMCID: PMC3096592 DOI: 10.1371/journal.pntd.0001144] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 02/27/2011] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Snake bite is a common medical emergency in Papua New Guinea (PNG). The taipan, Oxyuranus scutellatus, inflicts a large number of bites that, in the absence of antivenom therapy, result in high mortality. Parenteral administration of antivenoms manufactured in Australia is the current treatment of choice for these envenomings. However, the price of these products is high and has increased over the last 25 years; consequently the country can no longer afford all the antivenom it needs. This situation prompted an international collaborative project aimed at generating a new, low-cost antivenom against O. scutellatus for PNG. METHODOLOGY/PRINCIPAL FINDINGS A new monospecific equine whole IgG antivenom, obtained by caprylic acid fractionation of plasma, was prepared by immunising horses with the venom of O. scutellatus from PNG. This antivenom was compared with the currently used F(ab')(2) monospecific taipan antivenom manufactured by CSL Limited, Australia. The comparison included physicochemical properties and the preclinical assessment of the neutralisation of lethal neurotoxicity and the myotoxic, coagulant and phospholipase A(2) activities of the venom of O. scutellatus from PNG. The F(ab')(2) antivenom had a higher protein concentration than whole IgG antivenom. Both antivenoms effectively neutralised, and had similar potency, against the lethal neurotoxic effect (both by intraperitoneal and intravenous routes of injection), myotoxicity, and phospholipase A(2) activity of O. scutellatus venom. However, the whole IgG antivenom showed a higher potency than the F(ab')(2) antivenom in the neutralisation of the coagulant activity of O. scutellatus venom from PNG. CONCLUSIONS/SIGNIFICANCE The new whole IgG taipan antivenom described in this study compares favourably with the currently used F(ab')(2) antivenom, both in terms of physicochemical characteristics and neutralising potency. Therefore, it should be considered as a promising low-cost candidate for the treatment of envenomings by O. scutellatus in PNG, and is ready to be tested in clinical trials.
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Affiliation(s)
- Mariángela Vargas
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Alvaro Segura
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Mauren Villalta
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Ricardo Estrada
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Maykel Cerdas
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Owen Paiva
- School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Teatulohi Matainaho
- School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Simon D. Jensen
- School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
- Australian Venom Research Unit, University of Melbourne, Parkville, Australia
| | - Kenneth D. Winkel
- Australian Venom Research Unit, University of Melbourne, Parkville, Australia
| | - Guillermo León
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - David J. Williams
- School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
- Australian Venom Research Unit, University of Melbourne, Parkville, Australia
- Nossal Institute for Global Health, University of Melbourne, Parkville, Australia
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Blacklow B, Kornhauser R, Hains PG, Loiacono R, Escoubas P, Graudins A, Nicholson GM. α-Elapitoxin-Aa2a, a long-chain snake α-neurotoxin with potent actions on muscle (α1)2βγδ nicotinic receptors, lacks the classical high affinity for neuronal α7 nicotinic receptors. Biochem Pharmacol 2011; 81:314-25. [DOI: 10.1016/j.bcp.2010.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 10/02/2010] [Accepted: 10/05/2010] [Indexed: 10/19/2022]
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