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Coimbra FCP, Sanchez EE, Lomonte B, Gutiérrez JM, Calvete JJ, Fry BG. Blood Lines: Intraspecific and Interspecific Variations in Anticoagulant Actions of Agkistrodon Viperid Venoms. Toxins (Basel) 2024; 16:291. [PMID: 39057931 PMCID: PMC11281148 DOI: 10.3390/toxins16070291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 06/23/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
This study investigated the intraspecific and interspecific variability in the venom effects of Agkistrodon viperid snake species and subspecies (eleven venoms total) on plasma clotting times, fibrinogen levels, and fibrin clot strength. Significant delays in plasma clotting time were observed for A. conanti, A. contortrix mokasen, A. contortrix phaeogaster, A. howardgloydi, A. piscivorus leucostoma, and A. piscivorus piscivorus. Notably, the phylogenetically disjunct lineages A. conanti, A. contortrix mokasen, and A. howardgloydi exhibited the most potent anticoagulant effects, indicating the independent amplification of a basal trait. Inhibition assays with the activated clotting enzymes Factors XIa, IXa, Xa, and IIa (thrombin) revealed that FXa inhibition is another basal trait amplified independently on multiple occasions within the genus, but with A. howardgloydi, notably more potent than all others. Phospholipid degradation and zymogen destruction were identified as mechanisms underlying the variability in venom effects observed experimentally and in previous clinical reports. Thromboelastography demonstrated that the venoms did not clot fibrinogen directly but affected fibrin clot strength by damaging fibrinogen and that thrombin was subsequently only able to cleave into weak, unstable clots. The ability to activate Protein C, an endogenous anticoagulant enzyme, varied across species, with some venoms exceeding that of A. contortrix contortrix, which previously yielded the protein diagnostic agent Protac®. Phylogenetic analysis suggested that both fibrinogen degradation and Protein C activation were each amplified multiple times within the genus, albeit with negative correlation between these two modes of action. This study highlights the evolutionary, clinical, and biodiscovery implications of venom variability in the Agkistrodon species, underscoring their dynamic evolution, emphasising the need for tailored clinical approaches, and highlighting the potential for novel diagnostic and therapeutic developments inspired by the unique properties of snake venoms.
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Affiliation(s)
- Francisco C. P. Coimbra
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
| | - Elda E. Sanchez
- National Natural Toxins Research Center, Department of Chemistry, Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA;
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - Juan J. Calvete
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, CSIC, 46010 Valencia, Spain;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
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Dobson J, Chowdhury A, Tai-A-Pin J, van der Ploeg H, Gillett A, Fry BG. The Clot Thickens: Differential Coagulotoxic and Cardiotoxic Activities of Anguimorpha Lizard Venoms. Toxins (Basel) 2024; 16:283. [PMID: 38922177 PMCID: PMC11209219 DOI: 10.3390/toxins16060283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Despite their evolutionary novelty, lizard venoms are much less studied in comparison to the intense research on snake venoms. While the venoms of helodermatid lizards have long been assumed to be for defensive purposes, there is increasing evidence of toxic activities more useful for predation than defence (such as paralytic neurotoxicity). This study aimed to ascertain the effects of Heloderma, Lanthanotus, and Varanus lizard venoms on the coagulation and cardiovascular systems. Anticoagulant toxicity was demonstrated for the Varanus species studied, with the venoms prolonging clotting times in human and bird plasma due to the destructive cleavage of fibrinogen. In contrast, thromboelastographic analyses on human and bird plasmas in this study demonstrated a procoagulant bioactivity for Heloderma venoms. A previous study on Heloderma venom using factor-depleted plasmas as a proxy model suggested a procoagulant factor was present that activated either Factor XI or Factor XII, but could not ascertain the precise target. Our activation studies using purified zymogens confirmed FXII activation. Comparisons of neonate and adult H. exasperatum, revealed the neonates to be more potent in the ability to activate FXII, being more similar to the venom of the smaller species H. suspectum than the adult H. exasperatum. This suggests potent FXII activation a basal trait in the genus, present in the small bodied last common ancestor. This also indicates an ontogenetic difference in prey preferences in the larger Heloderma species paralleing the change in venom biochemistry. In addition, as birds lack Factor XII, the ability to clot avian plasma suggested an additional procoagulant site of action, which was revealed to be the activation of Factor VII, with H. horridum being the most potent. This study also examined the effects upon the cardiovascular system, including the liberation of kinins from kininogen, which contributes to hypotension induction. This form of toxicity was previously described for Heloderma venoms, and was revealed in this study was to also be a pathophysiological effect of Lanthanotus and Varanus venoms. This suggests that this toxic activity was present in the venom of the last common ancestor of the anguimorph lizards, which is consistent with kallikrein enzymes being a shared toxin trait. This study therefore uncovered novel actions of anguimorph lizard venoms, not only contributing to the evolutionary biology body of knowledge but also revealing novel activities to mine for drug design lead compounds.
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Affiliation(s)
- James Dobson
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | - Abhinandan Chowdhury
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | | | - Harold van der Ploeg
- Working Group Adder Research Netherlands, RAVON, 6525 ED Nijmegen, The Netherlands;
| | - Amber Gillett
- FaunaVet Wildlife Consultancy, Glass House Mountains, QLD 4518, Australia;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
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Jones L, Waite C, Neri-Castro E, Fry BG. Comparative Analysis of Alpha-1 Orthosteric-Site Binding by a Clade of Central American Pit Vipers (Genera Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium). Toxins (Basel) 2023; 15:487. [PMID: 37624244 PMCID: PMC10467085 DOI: 10.3390/toxins15080487] [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: 05/22/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/26/2023] Open
Abstract
The distribution and relative potency of post-synaptic neurotoxic activity within Crotalinae venoms has been the subject of less investigation in comparison with Elapidae snake venoms. No previous studies have investigated post-synaptic neurotoxic activity within the Atropoides, Metlapilcoatlus, Cerrophidion, and Porthidium clade. Given the specificity of neurotoxins to relevant prey types, we aimed to uncover any activity present within this clade of snakes that may have been overlooked due to lower potency upon humans and thus not appearing as a clinical feature. Using biolayer interferometry, we assessed the relative binding of crude venoms to amphibian, lizard, bird, rodent and human α-1 nAChR orthosteric sites. We report potent alpha-1 orthosteric site binding in venoms from Atropoides picadoi, Metlapilcoatlus occiduus, M. olmec, M. mexicanus, M. nummifer. Lower levels of binding, but still notable, were evident for Cerrophidion godmani, C. tzotzilorum and C. wilsoni venoms. No activity was observed for Porthidium venoms, which is consistent with significant alpha-1 orthosteric site neurotoxicity being a trait that was amplified in the last common ancestor of Atropoides/Cerrophidion/Metlapilcoatlus subsequent to the split by Porthidium. We also observed potent taxon-selective activity, with strong selection for non-mammalian targets (amphibian, lizard, and bird). As these are poorly studied snakes, much of what is known about them is from clinical reports. The lack of affinity towards mammalian targets may explain the knowledge gap in neurotoxic activity within these species, since symptoms would not appear in bite reports. This study reports novel venom activity, which was previously unreported, indicating toxins that bind to post-synaptic receptors may be more widespread in pit vipers than previously considered. While these effects appear to not be clinically significant due to lineage-specific effects, they are of significant evolutionary novelty and of biodiscovery interest. This work sets the stage for future research directions, such as the use of in vitro and in vivo models to determine whether the alpha-1 orthosteric site binding observed within this study confers neurotoxic venom activity.
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Affiliation(s)
- Lee Jones
- Venom Evolution Laboratory, School of the Environment, University of Queensland, St Lucia, Queensland 4072, Australia;
| | - Callum Waite
- Venom Evolution Laboratory, School of the Environment, University of Queensland, St Lucia, Queensland 4072, Australia;
| | - Edgar Neri-Castro
- Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad s/n. Fracc. Filadelfia, Gómez Palacio 35010, Dgo., Mexico;
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Chamilpa, Cuernavaca 62210, Mor., Mexico
| | - Bryan G. Fry
- Venom Evolution Laboratory, School of the Environment, University of Queensland, St Lucia, Queensland 4072, Australia;
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Deikumah JP, Biney RP, Awoonor-Williams JK, Gyakobo MK. Compendium of medically important snakes, venom activity and clinical presentations in Ghana. PLoS Negl Trop Dis 2023; 17:e0011050. [PMID: 37506181 PMCID: PMC10411737 DOI: 10.1371/journal.pntd.0011050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 08/09/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Snake bite envenoming (SBE) is one neglected tropical disease that has not received the needed attention. The sequelae of burdensome disability and mortality impact the socioeconomic life of communities adversely with little documentation of SBE in health facility records in Ghana. This study details SBE and snake distribution, habits/habitats, type of venom expressed and clinical manifestations. METHODOLOGY We conducted a structured thematic desk review of peer reviewed papers, books and reports from repositories including PubMed, World Health Organization (WHO) and Women's & Children's Hospital (WCH) Clinical Toxinology Resources using bibliographic software EndNote and search engine Google Scholar with the following key words; snakes, medical importance, snake bites, venom and venom type, envenomation, symptoms and signs, vaccines, venom expenditure, strike behaviour and venom-metering + Ghana, West Africa, Africa, World. We also reviewed data from the District Health Information Management System (DHIMS) of the Ghana Health Service (GHS). Outcome variables were organized as follows: common name (s), species, habitat/habit, species-specific toxin, clinical manifestation, antivenom availability, WHO category. FINDINGS Snake bites and SBE were grouped by the activity of the expressed venom into neurotoxic, cardiotoxic, haemorrhagic, cytotoxic, myotoxic, nephrotoxic and procoagulants. Neurotoxic snake bites were largely due to elapids. Expressed venoms with cardiotoxic, haemorrhagic, nephrotoxic and procoagulant activities principally belonged to the family Viperidae. Snakes with venoms showing myotoxic activity were largely alien to Ghana and the West African sub-region. Venoms showing cytotoxic activity are expressed by a wide range of snakes though more prevalent among the Viperidae family. Snakes with neurotoxic and haemorrhagic venom activities are prevalent across all the agro-ecological zones in Ghana. CONCLUSION/SIGNIFICANCE Understanding the characteristics of snakes and their venoms is useful in the management of SBE. The distribution of snakes by their expressed venoms across the agro-ecological zones is also instructive to species identification and diagnosis of SBE.
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Affiliation(s)
- Justus Precious Deikumah
- Department of Conservation Biology and Entomology, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Robert Peter Biney
- Department of Pharmacotherapeutics and Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | | | - Mawuli Kotope Gyakobo
- Department of Internal Medicine and Therapeutics, School of Medical Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
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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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Chowdhury A, Lewin MR, Carter RW, Casewell NR, Fry BG. Keel venom: Rhabdophis subminiatus (red-necked keelback) venom pathophysiologically affects diverse blood clotting pathways. Toxicon 2022; 218:19-24. [PMID: 36057394 DOI: 10.1016/j.toxicon.2022.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/02/2022] [Accepted: 08/24/2022] [Indexed: 10/14/2022]
Abstract
Venoms are evolutionary novelties that have real-world implications due to their impact upon human health. However, relative to the abundant studies of elapid and viperid snake venoms, fewer investigations have been undertaken on those of rear-fanged snakes as they are more problematic for obtaining venom. While most rear-fanged venomous snakes are not considered to be of great medical importance, several species are capable of producing fatalities. Most notable among these are snakes from the genus Rhabdophis, the Asian "keelback" snakes. Prior work have described potent procoagulant toxicity suggesting Factor X and prothrombin activation, but did not investigate the ability to activate other clotting factors. Here we show that in addition to activating both Factor X and prothrombin (with prothrombin twice that of FX), the venom of Rhabdophis subminiatus is able to more potently activate Factor VII (ten times that of prothrombin), while also activating FXII and FIX equipotently to prothrombin, and with FXI also activated but at a much lower level. The ability to activate FVII represents a third convergent evolution of this trait. The Australian elapid clade of [Oxyuranus (taipans) + Pseudonaja (brown snakes)] was the first identified to have evolved this trait. and only recently was it shown to be independently present in another lineage (the Central American viperid species Porthidium volcanicum). In addition, the abilities to activate FXI and FXII are also convergent between R. subminiatus and P. volcanicum, but with R. subminiatus being much more potent. By testing across amphibian, avian, and mammalian plasmas we demonstrate that the venom is potently procoagulant across diverse plasma types. However, consistent with dietary preference, R. subminiatus venom was most potent upon amphibian plasma. While a Rhabdophis antivenom is produced in Japan to treat R. tigrinus envenomings, it is scarce even within Japan and is not exported. As this genus is very wide-ranging in Asia, alternate treatment options are in need of development. Hence we tested the ability of candidate, broad-spectrum enzyme inhibitors to neutralize R. subminiatus venom: marimastat was more effective than prinomastat but both marimastat and prinomastat were significantly more effective than DMPS (2,3-Dimercapto-1-propanesulfonic acid). The findings of this study shed light on the evolution of these fascinating rear-fanged snakes as well as explored their systemic effects upon blood coagulation and point to potential treatment options for the rare, but potentially lethal encounters.
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Affiliation(s)
- Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia; Department of Biochemistry & Microbiology, North South University, Dhaka, Bangladesh.
| | - Matthew R Lewin
- Ophirex Inc., Corte Madera, CA, 94925, USA; California Academy of Sciences, San Francisco, CA, 94118, USA
| | | | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia.
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Jones L, Youngman NJ, Neri-Castro E, Guadarrama-Martínez A, Lewin MR, Carter R, Frank N, Fry BG. Differential Antivenom and Small-Molecule Inhibition of Novel Coagulotoxic Variations in Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium American Viperid Snake Venoms. Toxins (Basel) 2022; 14:toxins14080511. [PMID: 35893753 PMCID: PMC9332056 DOI: 10.3390/toxins14080511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
Within Neotropical pit-vipers, the Mexican/Central-American clade consisting of Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium is a wide-ranging, morphologically and ecologically diverse group of snakes. Despite their prevalence, little is known of the functional aspects of their venoms. This study aimed to fill the knowledge gap regarding coagulotoxic effects and to examine the potential of different therapeutic approaches. As a general trait, the venoms were shown to be anticoagulant but were underpinned by diverse biochemical actions. Pseudo-procoagulant activity (i.e., thrombin-like), characterized by the direct cleavage of fibrinogen to form weak fibrin clots, was evident for Atropoides picadoi, Cerrophidiontzotzilorum, Metlapilcoatlus mexicanus, M. nummifer, M. occiduus, M. olmec, and Porthidium porrasi. In contrast, other venoms cleaved fibrinogen in a destructive (non-clotting) manner, with C. godmani and C. wilsoni being the most potent. In addition to actions on fibrinogen, clotting enzymes were also inhibited. FXa was only weakly inhibited by most species, but Cerrophidion godmani and C. wilsoni were extremely strong in their inhibitory action. Other clotting enzymes were more widely inhibited by diverse species spanning the full taxonomical range, but in each case, there were species that had these traits notably amplified relatively to the others. C. godmani and C. wilsoni were the most potent amongst those that inhibited the formation of the prothrombinase complex and were also amongst the most potent inhibitors of Factor XIa. While most species displayed only low levels of thrombin inhibition, Porthidium dunni potently inhibited this clotting factor. The regional polyvalent antivenom produced by Instituto Picado Clodomiro was tested and was shown to be effective against the diverse anticoagulant pathophysiological effects. In contrast to the anticoagulant activities of the other species, Porthidium volcanicum was uniquely procoagulant through the activation of Factor VII and Factor XII. This viperid species is the first snake outside of the Oxyuranus/Pseudonaja elapid snake clade to be shown to activate FVII and the first snake venom of any kind to activate FXII. Interestingly, while small-molecule metalloprotease inhibitors prinomastat and marimastat demonstrated the ability to prevent the procoagulant toxicity of P. volcanicum, neither ICP antivenom nor inhibitor DMPS showed this effect. The extreme variation among the snakes here studied underscores how venom is a dynamic trait and how this can shape clinical outcomes and influence evolving treatment strategies.
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Affiliation(s)
- Lee Jones
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia;
- Correspondence: (L.J.); (B.G.F.)
| | - Nicholas J. Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia;
| | - Edgar Neri-Castro
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (E.N.-C.); (A.G.-M.)
| | - Alid Guadarrama-Martínez
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (E.N.-C.); (A.G.-M.)
| | | | - Rebecca Carter
- Ophirex Inc., Corte Madera, CA 94925, USA; (M.R.L.); (R.C.)
| | | | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia;
- Correspondence: (L.J.); (B.G.F.)
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Untangling interactions between Bitis vipers and their prey using coagulotoxicity against diverse vertebrate plasmas. Toxicon 2022; 216:37-44. [PMID: 35780972 DOI: 10.1016/j.toxicon.2022.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/13/2022] [Accepted: 06/27/2022] [Indexed: 11/23/2022]
Abstract
Venom is a key evolutionary innovation which plays a primary role in prey subjugation by venomous snakes. However, while there is a growing body of literature indicating the composition and activity of snake venoms is under strong natural selection driven by differences in prey physiology, the majority of studies have historically focussed on the activity of snake venoms with regards only towards human or mammalian physiologies. This study aimed to use clotting assays measuring both time and strength of clotting to characterise the coagulotoxic activity of venoms from a taxonomically, morphologically, and ecologically diverse range of Bitis spp. of viperid snakes upon the plasma of model species: amphibian (Cane Toad, Rhinella marina); lizard (Blue-tongue Skink, Tiliqua scincoides); avian (Domestic Chicken, Gallus gallus); and rodent (Brown Rat, Rattus norvegicus). Significant variation in coagulotoxic activity across the different plasmas was observed between species and compared to the known affects upon human plasma. Bitis caudalis was notable in being active on all four plasmas, but in extremely divergent manners: accelerating clotting times and producing strong, stable clots upon amphibian plasma (consistent with true procoagulation); accelerating clotting time but producing weak, unstable clots upon lizard plasma (consistent with pseudo-procoagulation); delaying avian clotting time beyond machine maximum reading time (strong anticoagulation consistent with either inhibition of clotting enzymes or total destruction of fibrinogen, or both); and delaying clotting of rodent plasma (consistent with inhibition of clotting enzymes) and with only weak clots formed (consistent with destruction of fibrinogen). In contrast, the sister species B. peringueyi and B. schneideri displayed activity only upon the lizard plasma, slightly accelerating the clotting times to produce weak, unstable clots (consistent with pseudo-procoagulation). The other dwarf species, B. cornuta, displayed strong anticoagulation upon avian and rodent plasmas, delaying clotting beyond the machine maximum reading time (strong anticoagulation consistent with either inhibition of clotting enzymes or total destruction of fibrinogen, or both). In contrast, the giant species studied (B. gabonica) showed only a very weak pseudo-procoagulant activity upon lizard plasma. The wide range of variation seen within this study highlights the importance of studying venom activity on relevant models when making conclusions about the ecological role of venoms and the extreme limitation in extrapolating animal results to predict potential human clinical effects.
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Youngman NJ, Peng YH, Harris RJ, Jones L, Llinas J, Haworth M, Gillett A, Fry BG. Differential coagulotoxic and neurotoxic venom activity from species of the arboreal viperid snake genus Bothriechis (palm-pitvipers). Comp Biochem Physiol C Toxicol Pharmacol 2022; 256:109326. [PMID: 35248757 DOI: 10.1016/j.cbpc.2022.109326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 12/15/2022]
Abstract
The viperid snake genus Bothriechis consists of eleven species distributed among Central and South America, living across low and high-altitude habitats. Despite Bothriechis envenomations being prominent across the Central and South American region, the functional effects of Bothriechis venoms are poorly understood. Thus, the aim of this study was to investigate the coagulotoxic and neurotoxic activities of Bothriechis venoms to fill this knowledge gap. Coagulotoxic investigations revealed Bothriechis nigroviridis and B. schlegelii to have pseudo-procoagulant venom activity, forming weak clots that rapidly break down, thereby depleting fibrinogen levels and thus contributing to a net anticoagulant state. While one sample of B. lateralis also showed weaker pseudo-procoagulant activity, directly clotting fibrinogen, two samples of B. lateralis venom were anticoagulant through the inhibition of thrombin and factor Xa activity. Differential efficacy of PoliVal-ICP antivenom was also observed, with the pseudo-procoagulant effect of B. nigroviridis venom poorly neutralised, despite this same activity in the venom of B. schlegelii being effectively neutralised. Significant specificity of these fibrinogen cleaving toxins was also observed, with no activity upon model amphibian, avian, lizard or rodent plasma observed. However, upon avian plasma the venom of B. nigroviridis exerted a complete anticoagulant effect, in contrast to the pseudo-procoagulant effect seen on human plasma. Neurotoxic investigations revealed B. schlegelii to be unique among the genus in having potent binding to the orthosteric site of the alpha-1 postsynaptic nicotinic acetylcholine receptor (with B. lateralis having a weaker but still discernible effect). This represents the first identification of postsynaptic nAChR neurotoxic activity for Bothriechis. In conclusion this study identifies notable differential activity within the coagulotoxic and postsynaptic neurotoxic activity of Bothriechis venoms, supporting previous research, and highlights the need for further studies with respect to antivenom efficacy as well as coagulotoxin specificity for Bothriechis venoms.
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Affiliation(s)
- Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Yin-Hsuan Peng
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Richard J Harris
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Lee Jones
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Mark Haworth
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
| | - Amber Gillett
- FaunaVet Wildlife Consultancy, Glass House Mountains, QLD 4518, Australia
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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10
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Youngman NJ, Lewin MR, Carter R, Naude A, Fry BG. Efficacy and Limitations of Chemically Diverse Small-Molecule Enzyme-Inhibitors against the Synergistic Coagulotoxic Activities of Bitis Viper Venoms. Molecules 2022; 27:1733. [PMID: 35268832 PMCID: PMC8911647 DOI: 10.3390/molecules27051733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/22/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022] Open
Abstract
Snakebite remains a significant public health burden globally, disproportionately affecting low-income and impoverished regions of the world. Recently, researchers have begun to focus on the use of small-molecule inhibitors as potential candidates for the neutralisation of key snake venom toxins and as potential field therapies. Bitis vipers represent some of the most medically important as well as frequently encountered snake species in Africa, with a number of species possessing anticoagulant phospholipase A2 (PLA2) toxins that prevent the prothrombinase complex from inducing clot formation. Additionally, species within the genus are known to exert pseudo-procoagulant activity, whereby kallikrein enzymatic toxins cleave fibrinogen to form a weak fibrin clot that rapidly degrades, thereby depleting fibrinogen levels and contributing to the net anticoagulant state. Utilising well-validated coagulation assays measuring time until clot formation, this study addresses the in vitro efficacy of three small molecule enzyme inhibitors (marimastat, prinomastat and varespladib) in neutralising these aforementioned activities. The PLA2 inhibitor varespladib showed the greatest efficacy for the neutralisation of PLA2-driven anticoagulant venom activity, with the metalloproteinase inhibitors prinomastat and marimastat both showing low and highly variable degrees of cross-neutralisation with PLA2 anticoagulant toxicity. However, none of the inhibitors showed efficacy in neutralising the pseudo-procoagulant venom activity exerted by the venom of B. caudalis. Our results highlight the complex nature of snake venoms, for which single-compound treatments will not be universally effective, but combinations might prove highly effective. Despite the limitations of these inhibitors with regards to in vitro kallikrein enzyme pseudo-procoagulant venom activity, our results further support the growing body of literature indicating the potential use of small molecule inhibitors to enhance first-aid treatment of snakebite envenoming, particularly in cases where hospital and thus antivenom treatment is either unavailable or far away.
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Affiliation(s)
- Nicholas J. Youngman
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Matthew R. Lewin
- California Academy of Sciences, San Francisco, CA 94118, USA;
- Ophirex Inc., Corte Madera, CA 94925, USA;
| | | | - Arno Naude
- Snakebite Assist, Pretoria ZA-0001, South Africa;
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD 4072, Australia
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11
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Youngman NJ, Carlsson DJ, Jones L, Neri-Castro E, Alago´n A, Fry BG. Cloud serpent coagulotoxicity: The biochemical mechanisms underpinning the anticoagulant actions of Mixcoatlus and Ophryacus venoms. Toxicon 2022; 211:44-49. [DOI: 10.1016/j.toxicon.2022.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 11/29/2022]
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12
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Zdenek CN, Chowdhury A, Haw GYH, Violette A, Fourmy R, Christ T, Vonk FJ, Fry BG. Taxon-selective venom variation in adult and neonate Daboia russelii (Russell's Viper), and antivenom efficacy. Toxicon 2022; 205:11-19. [PMID: 34752826 DOI: 10.1016/j.toxicon.2021.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/16/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022]
Abstract
Major variations in venom composition can occur between juvenile and adult venomous snakes. However, due to logistical constraints, antivenoms are produced using adult venoms in immunising mixtures, possibly resulting in limited neutralisation of juvenile snake venoms. Daboia russelii is one of the leading causes of snakebite death across South Asia. Its venom is potently procoagulant, causing stroke in prey animals but causing in humans consumptive coagulopathy-a net anticoagulant state-and sometimes death resulting from hemorrhage. In this in vitro study, we compared the venom activity of-and antivenom efficacy against-six 2-week-old D. russelii relative to that of their parents. Using a coagulation analyser, we quantified the relative coagulotoxicity of these venoms in human, avian, and amphibian plasma. The overall potency on human plasma was similar across all adult and neonate venoms, and SII (Serum Institute of India) antivenom was equipotent in neutralising these coagulotoxic effects. In addition, all venoms were also similar in their action upon avian plasma. In contrast, the neonate venoms were more potent on amphibian plasma, suggesting amphibians make up a larger proportion of neonate diet than adult diet. A similar venom potency in human and avian plasmas but varying selectivity for amphibian plasma suggests ontogenetic differences in toxin isoforms within the factor X or factor V activating classes, thereby providing a testable hypothesis for future transcriptomics work. By providing insights into the functional venom differences between adult and neonate D. russelii venoms, we hope to inform clinical treatment of patients envenomated by this deadly species and to shed new light on the natural history of these extremely medically important snakes.
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Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Grace Y H Haw
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Aude Violette
- Alphabiotoxine Laboratory Sprl, Barberie 15, 7911, Montroeul-au-bois, Belgium
| | - Rudy Fourmy
- Alphabiotoxine Laboratory Sprl, Barberie 15, 7911, Montroeul-au-bois, Belgium
| | | | - Freek J Vonk
- Naturalis Biodiversity Center, Leiden, the Netherlands; Division of BioAnalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia.
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13
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Puzari U, Fernandes PA, Mukherjee AK. Advances in the Therapeutic Application of Small-Molecule Inhibitors and Repurposed Drugs against Snakebite. J Med Chem 2021; 64:13938-13979. [PMID: 34565143 DOI: 10.1021/acs.jmedchem.1c00266] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The World Health Organization has declared snakebite as a neglected tropical disease. Antivenom administration is the sole therapy against venomous snakebite; however, several limitations of this therapy reinforce the dire need for an alternative and/or additional treatment against envenomation. Inhibitors against snake venoms have been explored from natural resources and are synthesized in the laboratory; however, repurposing of small-molecule therapeutics (SMTs) against the principal toxins of snake venoms to inhibit their lethality and/or obnoxious effect of envenomation has been garnering greater attention owing to their established pharmacokinetic properties, low-risk attributes, cost-effectiveness, ease of administration, and storage stability. Nevertheless, SMTs are yet to be approved and commercialized for snakebite treatment. Therefore, we have systematically reviewed and critically analyzed the scenario of small synthetic inhibitors and repurposed drugs against snake envenomation from 2005 to date and proposed novel approaches and commercialization strategies for the development of efficacious therapies against snake envenomation.
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Affiliation(s)
- Upasana Puzari
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur-784028, Assam, India
| | - Pedro Alexandrino Fernandes
- LAQV@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua Do Campo Alegre S/N, 4169-007 Porto, Portugal
| | - Ashis K Mukherjee
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur-784028, Assam, India.,Institute of Advanced Study in Science and Technology, Vigyan Path Garchuk, Paschim Boragaon, Guwahati-781035, Assam, India
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14
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Youngman NJ, Llinas J, Fry BG. Evidence for Resistance to Coagulotoxic Effects of Australian Elapid Snake Venoms by Sympatric Prey (Blue Tongue Skinks) but Not by Predators (Monitor Lizards). Toxins (Basel) 2021; 13:toxins13090590. [PMID: 34564595 PMCID: PMC8473410 DOI: 10.3390/toxins13090590] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/30/2021] [Accepted: 08/23/2021] [Indexed: 11/16/2022] Open
Abstract
Some Australian elapids possess potently procoagulant coagulotoxic venoms which activate the zymogen prothrombin into the functional enzyme thrombin. Although the activity of Australian elapid prothrombin-activators has been heavily investigated with respect to the mammalian, and in particular, human clotting cascades, very few studies have investigated the activity of their venom upon reptile plasmas. This is despite lizards representing both the primary diet of most Australian elapids and also representing natural predators. This study investigated the procoagulant actions of a diverse range of Australian elapid species upon plasma from known prey species within the genera Tiliqua (blue tongue skinks) as well as known predator species within the genera Varanus (monitor lizards). In addition to identifying significant variation in the natural responses of the coagulation cascade between species from the genera Tiliqua and Varanus relative to each other, as well as other vertebrate lineages, notable differences in venom activity were also observed. Within the genus Tiliqua, both T. rugosa and T. scincoides plasma displayed significant resistance to the procoagulant activity of Pseudechis porphyriacus venom, despite being susceptible to all other procoagulant elapid venoms. These results indicate that T. rugosa and T. scincoides have evolved resistance within their plasma to the coagulotoxic venom activity of the sympatric species P. porphyriacus. Other venoms were able to activate Tiliqua prothrombin, which suggests that the lessened activity of P. porphyriacus venom is not due to modifications of the prothrombin and may instead be due to a serum factor that specifically binds to P. porphyriacus toxins, as has been previously seen for squirrels resistant to rattlesnake venom. In contrast, none of the predatory lizards studied (Varanus giganteus, V. mertensi and V. varius) demonstrated resistance to the venom. This suggests that the mechanical protection afforded by thick osteodermic scales, and prey handling behaviour, removes a selection pressure for the evolution of resistance in these large predatory lizards. These results therefore reveal differential interactions between venoms of snakes with sympatric lizards that are on opposite sides of the predator-prey arms race.
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Affiliation(s)
- Nicholas J. Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia;
| | | | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia;
- Correspondence:
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15
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Seneci L, Zdenek CN, Bourke LA, Cochran C, Sánchez EE, Neri-Castro E, Bénard-Valle M, Alagón A, Frank N, Fry BG. A symphony of destruction: Dynamic differential fibrinogenolytic toxicity by rattlesnake (Crotalus and Sistrurus) venoms. Comp Biochem Physiol C Toxicol Pharmacol 2021; 245:109034. [PMID: 33766656 PMCID: PMC8162888 DOI: 10.1016/j.cbpc.2021.109034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/02/2021] [Accepted: 03/15/2021] [Indexed: 12/15/2022]
Abstract
What factors influence the evolution of a heavily selected functional trait in a diverse clade? This study adopts rattlesnakes as a model group to investigate the evolutionary history of venom coagulotoxicity in the wider context of phylogenetics, natural history, and biology. Venom-induced clotting of human plasma and fibrinogen was determined and mapped onto the rattlesnake phylogenetic tree to reconstruct the evolution of coagulotoxicity across the group. Our results indicate that venom phenotype is often independent of phylogenetic relationships in rattlesnakes, suggesting the importance of diet and/or other environmental variables in driving venom evolution. Moreover, the striking inter- and intraspecific variability in venom activity on human blood highlights the considerable variability faced by physicians treating envenomation. This study is the most comprehensive effort to date to describe and characterize the evolutionary and biological aspects of coagulotoxins in rattlesnake venom. Further research at finer taxonomic levels is recommended to elucidate patterns of variation within species and lineages.
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Affiliation(s)
- Lorenzo Seneci
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia; Institute of Biology Leiden (IBL), Leiden University, 2333 BE Leiden, the Netherlands
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Lachlan A Bourke
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Chip Cochran
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Elda E Sánchez
- National Natural Toxins Research Center (NNTRC), Department of Chemistry, Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA
| | - Edgar Neri-Castro
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Melisa Bénard-Valle
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Alejandro Alagón
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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16
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Damm M, Hempel BF, Süssmuth RD. Old World Vipers-A Review about Snake Venom Proteomics of Viperinae and Their Variations. Toxins (Basel) 2021; 13:toxins13060427. [PMID: 34204565 PMCID: PMC8235416 DOI: 10.3390/toxins13060427] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022] Open
Abstract
Fine-tuned by millions of years of evolution, snake venoms have frightened but also fascinated humanity and nowadays they constitute potential resources for drug development, therapeutics and antivenoms. The continuous progress of mass spectrometry techniques and latest advances in proteomics workflows enabled toxinologists to decipher venoms by modern omics technologies, so-called ‘venomics’. A tremendous upsurge reporting on snake venom proteomes could be observed. Within this review we focus on the highly venomous and widely distributed subfamily of Viperinae (Serpentes: Viperidae). A detailed public literature database search was performed (2003–2020) and we extensively reviewed all compositional venom studies of the so-called Old-World Vipers. In total, 54 studies resulted in 89 venom proteomes. The Viperinae venoms are dominated by four major, four secondary, six minor and several rare toxin families and peptides, respectively. The multitude of different venomics approaches complicates the comparison of venom composition datasets and therefore we differentiated between non-quantitative and three groups of quantitative workflows. The resulting direct comparisons within these groups show remarkable differences on the intra- and interspecies level across genera with a focus on regional differences. In summary, the present compilation is the first comprehensive up-to-date database on Viperinae venom proteomes and differentiating between analytical methods and workflows.
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Affiliation(s)
- Maik Damm
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany;
| | - Benjamin-Florian Hempel
- BIH Center for Regenerative Therapies, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, (BCRT), 10117 Berlin, Germany;
| | - Roderich D. Süssmuth
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany;
- Correspondence: ; Tel.: +49-(0)30-314-24205
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17
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Chowdhury A, Zdenek CN, Lewin MR, Carter R, Jagar T, Ostanek E, Harjen H, Aldridge M, Soria R, Haw G, Fry BG. Venom-Induced Blood Disturbances by Palearctic Viperid Snakes, and Their Relative Neutralization by Antivenoms and Enzyme-Inhibitors. Front Immunol 2021; 12:688802. [PMID: 34177943 PMCID: PMC8222980 DOI: 10.3389/fimmu.2021.688802] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/25/2021] [Indexed: 12/19/2022] Open
Abstract
Palearctic vipers are medically significant snakes in the genera Daboia, Macrovipera, Montivipera, and Vipera which occur throughout Europe, Central Asia, Near and Middle East. While the ancestral condition is that of a small-bodied, lowland species, extensive diversification has occurred in body size, and niche specialization. Using 27 venom samples and a panel of in vitro coagulation assays, we evaluated the relative coagulotoxic potency of Palearctic viper venoms and compared their neutralization by three antivenoms (Insoserp Europe, VIPERFAV and ViperaTAb) and two metalloprotease inhibitors (prinomastat and DMPS). We show that variation in morphology parallels variation in the Factor X activating procoagulant toxicity, with the three convergent evolutions of larger body sizes (Daboia genus, Macrovipera genus, and Vipera ammodytes uniquely within the Vipera genus) were each accompanied by a significant increase in procoagulant potency. In contrast, the two convergent evolutions of high altitude specialization (the Montivipera genus and Vipera latastei uniquely within the Vipera genus) were each accompanied by a shift away from procoagulant action, with the Montivipera species being particularly potently anticoagulant. Inoserp Europe and VIPERFAV antivenoms were both effective against a broad range of Vipera species, with Inoserp able to neutralize additional species relative to VIPERFAV, reflective of its more complex antivenom immunization mixture. In contrast, ViperaTAb was extremely potent in neutralizing V. berus but, reflective of this being a monovalent antivenom, it was not effective against other Vipera species. The enzyme inhibitor prinomastat efficiently neutralized the metalloprotease-driven Factor X activation of the procoagulant venoms. In contrast, DMPS (2,3-dimercapto-1-propanesulfonic acid), which as been suggested as another potential treatment option in the absence of antivenom, DMPS failed against all venoms tested. Overall, our results highlight the evolutionary variations within Palearctic vipers and help to inform clinical management of viper envenomation.
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Affiliation(s)
- Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
- Department of Biochemistry & Microbiology, North South University, Dhaka, Bangladesh
| | - Christina N. Zdenek
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
| | - Matthew R. Lewin
- California Academy of Sciences, San Francisco, CA, United States
- Ophirex, Inc., Corte Madera, CA, United States
| | | | | | | | - Hannah Harjen
- Department of Companion Animal Clinical Sciences, Norwegian University of Life Sciences, Ås, Norway
| | | | | | - Grace Haw
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, Australia
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18
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Clinical implications of ontogenetic differences in the coagulotoxic activity of Bothrops jararacussu venoms. Toxicol Lett 2021; 348:59-72. [PMID: 34044056 DOI: 10.1016/j.toxlet.2021.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 11/23/2022]
Abstract
Is snake venom activity influenced by size? This is a long-standing question that can have important consequences for the treatment of snake envenomation. Ontogenetic shifts in venom composition are a well-documented characteristic of numerous snake species. Although snake venoms can cause a range of pathophysiological disturbances, establishing the coagulotoxic profiles related to such shifts is a justified approach because coagulotoxicity can be deadly, and its neutralisation is a challenge for current antivenom therapy. Thus, we aimed to assess the coagulotoxicity patterns on plasma and fibrinogen produced by B othrops jararacussu venoms from individuals of different sizes and sex, and the neutralisation potential of SAB (anti bothropic serum produced by Butantan Institute). The use of a metalloproteinase inhibitor (Prinomastat) and a serine proteinase inhibitor (AEBSF) enabled us to determine the toxin class responsible for the observed coagulopathy: activity on plasma was found to be metalloprotease driven, while the activity on fibrinogen is serine protease driven. To further explore differences in venom activity, the activation of Factor X and prothrombin as a function of snake size was also evaluated. All the venoms exhibited a potent procoagulant effect upon plasma and were less potent in their pseudo-procoagulant clotting effect upon fibrinogen. On human plasma, the venoms from smaller snakes produced more rapid clotting than the larger ones. In contrast, the venom activity on fibrinogen had no relation with size or sex. The difference in procoagulant potency was correlated with the bigger snakes being proportionally better neutralized by antivenom due to the lower levels of procoagulant toxins, than the smaller. Thus, while the antivenom ultimately neutralized the venoms, proportionally more would be needed for an equal mass of venom from a small snake than a large one. Similarly, the neutralisation by SAB of the pseudo-procoagulant clotting effects was also correlated with relative potency, with the smaller and bigger snakes being neutralized proportional to potency, but with no correlation to size. Thromboelastography (TEG) tests on human and toad plasma revealed that small snakes' venoms acted quicker than large snakes' venom on both plasmas, with the action upon amphibian plasma consistent with smaller snakes taking a larger proportion of anuran prey than adults. Altogether, the ontogenetic differences regarding coagulotoxic potency and corresponding impact upon relative antivenom neutralisation of snakes with different sizes were shown, underscoring the medical importance of investigating ontogenetic changes in order to provide data crucial for evidence-based design of clinical management strategies.
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19
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Harris RJ, Youngman NJ, Chan W, Bosmans F, Cheney KL, Fry BG. Getting stoned: Characterisation of the coagulotoxic and neurotoxic effects of reef stonefish (Synanceia verrucosa) venom. Toxicol Lett 2021; 346:16-22. [PMID: 33878385 DOI: 10.1016/j.toxlet.2021.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/11/2021] [Accepted: 04/13/2021] [Indexed: 01/11/2023]
Abstract
The reef stonefish (Synanceia verrucosa) is a venomous fish which causes excruciatingly painful envenomations. While some research on the pathophysiology and functions of the venom have been conducted, there are still some gaps in the understanding of the venom effects due to the extreme lability of fish venom toxins and the lack of available testing platforms. Here we set out to assess new functions of the venom whilst also attempting to address some unclear pathophysiological effects from previous literature. Utilising a biolayer interferometry assay, our results highlight that the venom binds to the orthosteric site of the α-1 nicotinic acetylcholine receptor as well as the domain IV of voltage-gated Ca2+ (CaV1.2) channel mimotopes. Both these results add some clarity to the previously ambiguous literature. We further assessed the coagulotoxic effects of the venom using thromboelastography and Stago STA-R Max coagulation analyser assays. We reveal that the venom produced anticoagulant activity and significantly delayed time until clot formation of recalcified human plasma which is likely through the degradation of phospholipids. There was a difference between fresh and lyophilised venom activity toward the nicotinic acetylcholine receptor mimotopes and coagulation assays, whilst no difference was observed in the activity toward the domain IV of CaV1.2 mimotopes. This research adds further insights into the neglected area of fish venom whilst also highlighting the extreme labile nature of fish venom toxins.
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Affiliation(s)
- Richard J Harris
- Venom Evolution Laboratory, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Nicholas J Youngman
- Venom Evolution Laboratory, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Weili Chan
- Visual Ecology Laboratory, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia; School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000, Ghent, Belgium
| | - Karen L Cheney
- Visual Ecology Laboratory, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Bryan G Fry
- Venom Evolution Laboratory, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
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20
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Seneci L, Zdenek CN, Chowdhury A, Rodrigues CFB, Neri-Castro E, Bénard-Valle M, Alagón A, Fry BG. A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms. Front Immunol 2021; 12:612846. [PMID: 33815366 PMCID: PMC8011430 DOI: 10.3389/fimmu.2021.612846] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.
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Affiliation(s)
- Lorenzo Seneci
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Institute of Biology Leiden (IBL), Leiden University, Leiden, Netherlands
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Department of Biochemistry and Microbiology, North South University, Dhaka, Bangladesh
| | - Caroline F B Rodrigues
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Laboratório de Herpetologia, Instituto Butantan, São Paulo, Brazil
| | - Edgar Neri-Castro
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Melisa Bénard-Valle
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Alejandro Alagón
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
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21
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Youngman NJ, Chowdhury A, Zdenek CN, Coster K, Sundman E, Braun R, Fry BG. Utilising venom activity to infer dietary composition of the Kenyan horned viper (Bitis worthingtoni). Comp Biochem Physiol C Toxicol Pharmacol 2021; 240:108921. [PMID: 33122136 DOI: 10.1016/j.cbpc.2020.108921] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/29/2020] [Accepted: 10/18/2020] [Indexed: 02/07/2023]
Abstract
Bitis are well known for being some of the most commonly encountered and medically important snake species in all of Africa. While the majority of species possess potently anticoagulant venom, only B. worthingtoni is known to possess procoagulant venom. Although known to be the basal species within the genus, B. worthingtoni is an almost completely unstudied species with even basic dietary information lacking. This study investigated various aspects of the unique procoagulant effects of B. worthingtoni venom. Coagulation assays determined the primary procoagulant effect to be driven by Factor X activating snake venom metalloprotease toxins. In addition to acting upon the mammalian blood clotting cascade, B. worthingtoni venom was also shown to clot amphibian plasma. As previous studies have shown differences in clotting factors between amphibian and mammalian plasmas, individual enzymes in snake venoms acting on plasma clotting factors can be taxon-selective. As venoms evolve under purifying selection pressures, this suggests that the procoagulant snake venom metalloprotease toxins present in B. worthingtoni have likely been retained from a recent common ancestor shared with the related amphibian-feeding Proatheris superciliaris, and that both amphibians and mammals represent a substantial proportion of B. worthingtoni current diet. Thus, taxon-specific actions of venoms may have utility in inferring dietary composition for rare or difficult to study species. An important caveat is that to validate this hypothesis field studies investigating the dietary ecology of B. worthingtoni must be conducted, as well as further investigations of its venom composition to reconstruct the molecular evolutionary history of the toxins present.
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Affiliation(s)
- Nicholas J Youngman
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Abhinandan Chowdhury
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Christina N Zdenek
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Eric Sundman
- Universeum, Södra Vägen 50, 412 54 Gothenburg, Sweden
| | - Ralph Braun
- Serpentarium Calden, Birkenweg 11, 34379 Calden, Germany
| | - Bryan G Fry
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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22
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Widespread and Differential Neurotoxicity in Venoms from the Bitis Genus of Viperid Snakes. Neurotox Res 2021; 39:697-704. [PMID: 33428181 DOI: 10.1007/s12640-021-00330-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/02/2021] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
Research into the neurotoxic activity of venoms from species within the snake family Viperidae is relatively neglected compared with snakes in the Elapidae family. Previous studies into venoms from the Bitis genus of vipers have identified the presence of presynaptic phospholipase A2 neurotoxins in B. atropos and B. caudalis, as well as a postsynaptic phospholipase A2 in B. arietans. Yet, no studies have investigated how widespread neurotoxicity is across the Bitis genus or if they exhibit prey selectivity of their neurotoxins. Utilising a biolayer interferometry assay, we were able to assess the binding of crude venom from 14 species of Bitis to the neuromuscular α-1 nAChR orthosteric site across a wide range of vertebrate taxa mimotopes. Postsynaptic binding was seen for venoms from B. arietans, B. armata, B. atropos, B. caudalis, B. cornuta, B. peringueyi and B. rubida. To further explore the types of neurotoxins present, venoms from the representatives B. armata, B. caudalis, B. cornuta and B. rubida were additionally tested in the chick biventer cervicis nerve muscle preparation, which showed presynaptic and postsynaptic activity for B. caudalis and only presynaptic neurotoxicity for B. cornuta and B. rubida, with myotoxicity also evident for some species. These results, combined with the biolayer interferometry results, indicate complex neurotoxicity exerted by Bitis species, which varies dramatically by lineage tested upon. Our data also further support the importance of sampling across geographical localities, as significant intraspecific variation of postsynaptic neurotoxicity was reported across the different localities.
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23
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Chowdhury A, Zdenek CN, Dobson JS, Bourke LA, Soria R, Fry BG. Clinical implications of differential procoagulant toxicity of the palearctic viperid genus Macrovipera, and the relative neutralization efficacy of antivenoms and enzyme inhibitors. Toxicol Lett 2021; 340:77-88. [PMID: 33412251 DOI: 10.1016/j.toxlet.2020.12.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/20/2022]
Abstract
Species within the viperid genus Macrovipera are some of the most dangerous snakes in the Eurasian region, injecting copious amounts of potent venom. Despite their medical importance, the pathophysiological actions of their venoms have been neglected. Particularly poorly known are the coagulotoxic effects and thus the underlying mechanisms of lethal coagulopathy. In order to fill this knowledge gap, we ascertained the effects of venom upon human plasma for Macrovipera lebetina cernovi, M. l. lebetina, M. l. obtusa, M. l. turanica, and M. schweizeri using diverse coagulation analysing protocols. All five were extremely potent in their ability to promote clotting but varied in their relative activation of Factor X, being equipotent in this study to the venom of the better studied, and lethal, species Daboia russelii. The Insoserp European viper antivenom was shown to be highly effective against all the Macrovipera venoms, but performed poorly against the D. russelii venom. Reciprocally, while Daboia antivenoms performed well against D. russelii venom, they failed against Macrovipera venom. Thus despite the two genera sharing a venom phenotype (Factor X activation) driven by the same toxin type (P-IIId snake venom metalloproteases), the surface biochemistries of the toxins differed significantly enough to impede antivenom cross- neutralization. The differences in venom biochemistry were reflected in coagulation co-factor dependence. While both genera were absolutely dependent upon calcium for the activation of Factor X, dependence upon phospholipid varied. The Macrovipera venoms had low levels of dependence upon phospholipid while the Daboia venom was three times more dependent upon phospholipid for the activation of Factor X. This suggests that the sites on the molecular surface responsible for phospholipid dependence, are the same differential sites that prevent inter-genera antivenom cross- neutralization. Due to cold-chain requirements, antivenoms may not be stocked in rural settings where the need is at the greatest. Thus we tested the efficacy of enzyme inhibitor Prinomastat as a field-deployable treatment to stabilise patients while being transported to antivenom stocks, and showed that it was extremely effective in blocking the Factor X activating pathophysiological actions. Marimastat however was less effective. These results thus not only shed light on the coagulopathic mechanisms of Macrovipera venoms, but also provide data critical for evidence-based design of snakebite management strategies.
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Affiliation(s)
- Abhinandan Chowdhury
- Toxin Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, 4072, Australia; Department of Biochemistry & Microbiology, North South University, Dhaka, 1229, Bangladesh
| | - Christina N Zdenek
- Toxin Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - James S Dobson
- Toxin Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Lachlan A Bourke
- Toxin Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Raul Soria
- Inosan Biopharma, S.A. Arbea Campus Empresarial, Edificio 2, Planta 2, Carretera Fuencarral a Alcobendas, Km 3.8, 28108, Madrid, Spain
| | - Bryan G Fry
- Toxin Evolution Lab, School of Biological Science, University of Queensland, St. Lucia, QLD, 4072, Australia.
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24
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Youngman NJ, Walker A, Naude A, Coster K, Sundman E, Fry BG. Varespladib (LY315920) neutralises phospholipase A 2 mediated prothrombinase-inhibition induced by Bitis snake venoms. Comp Biochem Physiol C Toxicol Pharmacol 2020; 236:108818. [PMID: 32512199 DOI: 10.1016/j.cbpc.2020.108818] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 05/26/2020] [Accepted: 06/02/2020] [Indexed: 01/28/2023]
Abstract
Anticoagulant toxicity is a common function of venoms produced by species within the Bitis genus. Potent inhibition of the prothrombinase complex is an identified mechanism of action for the dwarf species B. cornuta and B. xeropaga, along with some localities of B. atropos and B. caudalis. Snake venom phospholipase A2 toxins that inhibit the prothrombinase complex have been identified in snake venom, including an isolated phospholipase A2 toxin from B. caudalis. Current research is investigating the ability of the drug varespladib to inhibit snake venom phospholipase A2 toxins and reduce their toxicity. In particular, varespladib is being investigated as a treatment that could be administered prior to hospital referral which is a major necessity for species such as those from the genus Bitis, due to envenomations often occurring in remote regions of Africa where antivenom is unavailable. Using previously validated coagulation assays, this study aimed to determine if the toxins responsible for inhibition of the prothrombinase complex in the venom of four Bitis species are phospholipase A2 toxins, and if varespladib is able to neutralise this anticoagulant activity. Our results demonstrate that varespladib strongly neutralises the prothrombinase-inhibiting effects of all venoms tested in this study, and that this prothrombinase-inhibiting mechanism of anticoagulant activity is driven by phospholipase A2 class toxins in these four species. This study extends previous reports demonstrating varespladib has broad efficacy for treatment of phospholipase A2 rich snake venoms, indicating it also inhibits their anticoagulant effects mediated by prothrombinase-inhibition.
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Affiliation(s)
- Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Andrew Walker
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD 4072, Australia
| | - Arno Naude
- Snakebite Assist, Pretoria ZA-0001, South Africa
| | | | - Eric Sundman
- Universeum, Södra Vägen 50, 412 54 Gothenburg, Sweden
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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25
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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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26
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Zdenek CN, Youngman NJ, Hay C, Dobson J, Dunstan N, Allen L, Milanovic L, Fry BG. Anticoagulant activity of black snake (Elapidae: Pseudechis) venoms: Mechanisms, potency, and antivenom efficacy. Toxicol Lett 2020; 330:176-184. [PMID: 32442717 DOI: 10.1016/j.toxlet.2020.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Venoms from Pseudechis species (Australian black snakes) within the Elapidae family are rich in anticoagulant PLA2 toxins, with the exception of one species (P. porphyriacus) that possesses procoagulant mutated forms of the clotting enzyme Factor Xa. Previously the mechanism of action of the PLA2 toxins' anticoagulant toxicity was said to be due to inhibition of Factor Xa, but this statement was evidence free. We conducted a series of anticoagulation assays to elucidate the mechanism of anticoagulant action produced by P. australis venom. Our results revealed that, rather than targeting FXa, the PLA2 toxins inhibited the prothrombinase complex, with FVa-alone or as part of the prothrombinase complex-as the primary target; but with significant thrombin inhibition also noted. In contrast, FXa, and other factors inhibited only to a lesser degree were minor targets. We quantified coagulotoxic effects upon human plasma caused by all nine anticoagulant Pseudechis species, including nine localities of P. australis across Australia, and found similar anticoagulant potency across all Pseudechis species, with greater potency in P. australis and the undescribed Pseudechis species in the NT. In addition, the northern localities and eastern of P. australis were significantly more potent than the central, western, and southern localities. All anticoagulant venoms responded well to Black Snake Antivenom, except P. colletti which was poorly neutralised by Black Snake Antivenom and also Tiger Snake Antivenom (the prescribed antivenom for this species). However, we found LY315920 (trade name: Varespladib), a small molecule inhibitor of PLA2 proteins, exhibited strong potency against P. colletti venom. Thus, Varespladib may be a clinically viable treatment for anticoagulant toxicity exerted by this species that is not neutralised by available antivenoms. Our results provide insights into coagulotoxic venom function, and suggest future in vivo work be conducted to progress the development of a cheaper, first-line treatment option to treat PLA2-rich snake venoms globally.
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Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Chris Hay
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia; Australian School of Herpetology, Southport, QLD, Australia
| | - James Dobson
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA, 5352, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA, 5352, Australia
| | - Leontina Milanovic
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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27
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Bourke LA, Youngman NJ, Zdenek CN, Op den Brouw B, Violette A, Fourmy R, Fry BG. Trimeresurus albolabris snakebite treatment implications arising from ontogenetic venom comparisons of anticoagulant function, and antivenom efficacy. Toxicol Lett 2020; 327:2-8. [PMID: 32199952 DOI: 10.1016/j.toxlet.2020.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/01/2020] [Accepted: 03/14/2020] [Indexed: 01/19/2023]
Abstract
Does the venom of Trimeresurus albolabris (white-lipped pit viper) differ between neonate and adults? This species is responsible for most snakebites within south and southeast Asia, yet it is unknown whether ontogenetic variation in venom composition occurs in this species, or how this might affect antivenom efficacy. Using a coagulation analyser robot, we examined the anticoagulant activity of T. albolabris venom from eight individuals across multiple age classes. We then compared the efficacy of Thai Red Cross Green Pit Viper Antivenom across these age classes. Venoms from all age classes were equally potent in their pseudo-procoagulant, fibrinogenolytic activity, in that fibrinogen was cleaved to form weak, unstable fibrin clots that rapidly broke down, thus resulting in a net anticoagulant state. Similarly, this coagulotoxic activity was well neutralised by antivenom across all venoms. Given that coagulotoxicity is the primary serious pathology in T. albolabris envenomations, we conclude that Thai Red Cross Green Tree Pit Viper Antivenom is a valid treatment for envenomations by this species, regardless of age or sex of the offending snake. These results are relevant for clinical treatment of envenomations by T. albolabris.
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Affiliation(s)
- Lachlan A Bourke
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Nicholas J Youngman
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Aude Violette
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911, Montroeul-au-bois, Belgium
| | - Rudy Fourmy
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911, Montroeul-au-bois, Belgium
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia.
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