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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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2
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Yao Y, Kang H, Cheng Y, Su X, Wang B. Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation. Curr Mol Med 2024; 24:844-855. [PMID: 37340745 DOI: 10.2174/1566524023666230619102723] [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: 09/18/2022] [Revised: 04/24/2023] [Accepted: 05/04/2023] [Indexed: 06/22/2023]
Abstract
Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.
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Affiliation(s)
- Yan'er Yao
- Department of Cardiology, the Xiamen Cardiovascular Hospital of Xiamen University, Xiamen, Fujian, China
| | - Huiyuan Kang
- Department of Cardiology, the Xiamen Cardiovascular Hospital of Xiamen University, Xiamen, Fujian, China
| | - Ye Cheng
- Department of Cardiology, the Xiamen Cardiovascular Hospital of Xiamen University, Xiamen, Fujian, China
| | - Xin Su
- Department of Cardiology, the Xiamen Cardiovascular Hospital of Xiamen University, Xiamen, Fujian, China
| | - Bin Wang
- Department of Cardiology, the Xiamen Cardiovascular Hospital of Xiamen University, Xiamen, Fujian, China
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3
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Mancuso M, Zaman S, Maddock ST, Kamei RG, Salazar-Valenzuela D, Wilkinson M, Roelants K, Fry BG. Resistance Is Not Futile: Widespread Convergent Evolution of Resistance to Alpha-Neurotoxic Snake Venoms in Caecilians (Amphibia: Gymnophiona). Int J Mol Sci 2023; 24:11353. [PMID: 37511112 PMCID: PMC10379402 DOI: 10.3390/ijms241411353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Predatory innovations impose reciprocal selection pressures upon prey. The evolution of snake venom alpha-neurotoxins has triggered the corresponding evolution of resistance in the post-synaptic nicotinic acetylcholine receptors of prey in a complex chemical arms race. All other things being equal, animals like caecilians (an Order of legless amphibians) are quite vulnerable to predation by fossorial elapid snakes and their powerful alpha-neurotoxic venoms; thus, they are under strong selective pressure. Here, we sequenced the nicotinic acetylcholine receptor alpha-1 subunit of 37 caecilian species, representing all currently known families of caecilians from across the Americas, Africa, and Asia, including species endemic to the Seychelles. Three types of resistance were identified: (1) steric hindrance from N-glycosylated asparagines; (2) secondary structural changes due to the replacement of proline by another amino acid; and (3) electrostatic charge repulsion of the positively charged neurotoxins, through the introduction of a positively charged amino acid into the toxin-binding site. We demonstrated that resistance to alpha-neurotoxins convergently evolved at least fifteen times across the caecilian tree (three times in Africa, seven times in the Americas, and five times in Asia). Additionally, as several species were shown to possess multiple resistance modifications acting synergistically, caecilians must have undergone at least 20 separate events involving the origin of toxin resistance. On the other hand, resistance in non-caecilian amphibians was found to be limited to five origins. Together, the mutations underlying resistance in caecilians constitute a robust signature of positive selection which strongly correlates with elapid presence through both space (sympatry with caecilian-eating elapids) and time (Cenozoic radiation of elapids). Our study demonstrates the extent of convergent evolution that can be expected when a single widespread predatory adaptation triggers parallel evolutionary arms races at a global scale.
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Affiliation(s)
- Marco Mancuso
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Shabnam Zaman
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Simon T Maddock
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- School of Life Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
- Island Biodiversity and Conservation Centre, University of Seychelles, Mahé P.O. Box 1348, Seychelles
| | - Rachunliu G Kamei
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
- Amphibians and Reptiles Division, The Field Museum of Natural History, 1400 S Lake Shore Dr., Chicago, IL 60605, USA
| | - David Salazar-Valenzuela
- Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb) e Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias de Medio Ambiente, Universidad Indoamérica, Machala y Sabanilla, Quito EC170301, Ecuador
| | - Mark Wilkinson
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Bryan G Fry
- Venom Evolutionary Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
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4
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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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5
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Extreme Procoagulant Potency in Human Plasma of Venoms from the African Viperid Genera Atheris, Cerastes, and Proatheris and the Relative Efficacy of Antivenoms and Synthetic Enzyme-Inhibitors. Toxins (Basel) 2022; 14:toxins14120836. [PMID: 36548733 PMCID: PMC9788330 DOI: 10.3390/toxins14120836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/16/2022] [Accepted: 11/25/2022] [Indexed: 12/02/2022] Open
Abstract
The African viperid snake genera Atheris, Cerastes, and Proatheris are closely related, similar in size, but occupy extremely divergent ecological niches (arboreal in tropical rainforests, fossorial in deserts, and swamp-dwelling, respectively). Their venoms have not previously been subjected to comparative analyses for their action upon the coagulation of blood, most notably with significant data deficiencies from Atheris and Proatheris. In contrast, the closely related genus Echis is well-documented as capable of producing potent procoagulant effects. In light of this, we set out to compare the coagulotoxic actions of Atheris ceratophora, A. chlorechis, A. desaixi, A. nitschei, A. squamigera, C. cerastes, C. cerastes gasperettii, C. vipera, and Proatheris superciliaris and explore potential pharmacological interventions to reestablish normal blood coagulation. All venoms displayed extremely potent procoagulant effects, over twice as fast as the most potent Echis reported to date. Although Cerastes is used in the immunising mixture of two different regionally available antivenoms (Inoserp-MENA with C. cerastes, C. cerastes gasperettii, C. vipera and Saudi Arabian polyvalent with C. cerastes), none of the other species in this study are included in the immunising mixture of any antivenom. Notably, all the Cerastes species were only neutralised by the Inoserp-MENA antivenom. C. cerastes venom was not neutralised well by the Saudi Arabian antivenom, with the low levels of recognition for any of the Cerastes venoms suggesting a strong regional variation in the venom of this species, as the C. cerastes venom tested was of African (Tunisian) origin versus Saudi locality used in that antivenom's production. The other antivenoms (Micropharm EchiTAbG, ICP EchiTAb-Plus-ICP, Inosan Inoserp Pan-Africa, Premium Serums PANAF Sub-Sahara Africa, South African Vaccine Producers Echis, South African Vaccine Producers Polyvalent) all displayed trivial-to-no ability to neutralise the procoagulant toxicity of any of the Atheris, Cerastes, or Proatheris venoms. Comparative testing of the enzyme inhibitors DMPS, marimastat, and prinomastat, revealed a very potent neutralising capacity of marimastat, with prinomastat showing lower but still significant potency at the same molar concentration, while a 5× molar concentration of DMPS had no apparent effect on procoagulant venom effects normalized by the other inhibitors. These results and methods contribute to the body of knowledge of potential clinical effects and data necessary for evidence-based advancement of clinical management strategies.
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6
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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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7
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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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8
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Dynamic genetic differentiation drives the widespread structural and functional convergent evolution of snake venom proteinaceous toxins. BMC Biol 2022; 20:4. [PMID: 34996434 PMCID: PMC8742412 DOI: 10.1186/s12915-021-01208-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/06/2021] [Indexed: 12/25/2022] Open
Abstract
Background The explosive radiation and diversification of the advanced snakes (superfamily Colubroidea) was associated with changes in all aspects of the shared venom system. Morphological changes included the partitioning of the mixed ancestral glands into two discrete glands devoted for production of venom or mucous respectively, as well as changes in the location, size and structural elements of the venom-delivering teeth. Evidence also exists for homology among venom gland toxins expressed across the advanced snakes. However, despite the evolutionary novelty of snake venoms, in-depth toxin molecular evolutionary history reconstructions have been mostly limited to those types present in only two front-fanged snake families, Elapidae and Viperidae. To have a broader understanding of toxins shared among extant snakes, here we first sequenced the transcriptomes of eight taxonomically diverse rear-fanged species and four key viperid species and analysed major toxin types shared across the advanced snakes. Results Transcriptomes were constructed for the following families and species: Colubridae - Helicops leopardinus, Heterodon nasicus, Rhabdophis subminiatus; Homalopsidae – Homalopsis buccata; Lamprophiidae - Malpolon monspessulanus, Psammophis schokari, Psammophis subtaeniatus, Rhamphiophis oxyrhynchus; and Viperidae – Bitis atropos, Pseudocerastes urarachnoides, Tropidolaeumus subannulatus, Vipera transcaucasiana. These sequences were combined with those from available databases of other species in order to facilitate a robust reconstruction of the molecular evolutionary history of the key toxin classes present in the venom of the last common ancestor of the advanced snakes, and thus present across the full diversity of colubroid snake venoms. In addition to differential rates of evolution in toxin classes between the snake lineages, these analyses revealed multiple instances of previously unknown instances of structural and functional convergences. Structural convergences included: the evolution of new cysteines to form heteromeric complexes, such as within kunitz peptides (the beta-bungarotoxin trait evolving on at least two occasions) and within SVMP enzymes (the P-IIId trait evolving on at least three occasions); and the C-terminal tail evolving on two separate occasions within the C-type natriuretic peptides, to create structural and functional analogues of the ANP/BNP tailed condition. Also shown was that the de novo evolution of new post-translationally liberated toxin families within the natriuretic peptide gene propeptide region occurred on at least five occasions, with novel functions ranging from induction of hypotension to post-synaptic neurotoxicity. Functional convergences included the following: multiple occasions of SVMP neofunctionalised in procoagulant venoms into activators of the clotting factors prothrombin and Factor X; multiple instances in procoagulant venoms where kunitz peptides were neofunctionalised into inhibitors of the clot destroying enzyme plasmin, thereby prolonging the half-life of the clots formed by the clotting activating enzymatic toxins; and multiple occasions of kunitz peptides neofunctionalised into neurotoxins acting on presynaptic targets, including twice just within Bungarus venoms. Conclusions We found novel convergences in both structural and functional evolution of snake toxins. These results provide a detailed roadmap for future work to elucidate predator–prey evolutionary arms races, ascertain differential clinical pathologies, as well as documenting rich biodiscovery resources for lead compounds in the drug design and discovery pipeline. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01208-9.
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Pallett SJ, Handford C, Wong SM, West C, Moore LS. Necrosis and amputation following the bite of the Bibron's stiletto snake ( Atractaspis bibronii) with a concise review of current literature. Trop Doct 2021; 52:142-146. [PMID: 34490812 DOI: 10.1177/00494755211039638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Atractaspis bibronii are highly specialised snakes found across Southern Africa. Adapted for subterranean hunting of prey, snakes of the genus Atractaspis demonstrate a unique biting mechanism, with an ability to deliver venom via a single fang, protruded over an almost closed mouth in a side-to-side striking pattern. It is not possible to handle these snakes safely. Atractaspididae can be mistaken for medically insignificant snakes and often occur in remote areas that may lead to delayed or reduced presentation to suitable care facilities. We here report a case of an A. bibronii envenomation in remote Southern Africa to the right ring finger from a single fang with significant complication. Medical, and subsequently, surgical management of a progression from discolouration at the bite site, to spreading oedema, blistering, local necrosis and secondary infection required amputation of the digit.
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Affiliation(s)
- Scott Jc Pallett
- Specialist Registrar, Medical Microbiology and Infectious Diseases, Chelsea and Westminster Hospital NHS Foundation Trust, London, UK.,Fellow, Royal Geographical Society (with IBG), London, UK
| | - Charles Handford
- Fellow, Royal Geographical Society (with IBG), London, UK.,Specialist Registrar, Trauma and Orthopaedics, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Stephanie My Wong
- Fellow, Royal Geographical Society (with IBG), London, UK.,Post-graduate student, Edinburgh Medical School: Biomedical Sciences, University School of Edinburgh, Edinburgh, UK
| | - Collin West
- Medical Director, Consultant Trauma and Orthopaedic Surgeon, Medland Hospital, Lusaka, Zambia
| | - Luke Sp Moore
- Consultant Infectious Diseases, Microbiology and Virology, Chelsea and Westminster Hospital, London, UK.,Honorary Senior Clinical Lecturer, Imperial College London, NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, London, UK
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10
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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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11
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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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12
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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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13
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Harris RJ, Fry BG. Electrostatic resistance to alpha-neurotoxins conferred by charge reversal mutations in nicotinic acetylcholine receptors. Proc Biol Sci 2021; 288:20202703. [PMID: 33434458 DOI: 10.1098/rspb.2020.2703] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The evolution of venom resistance through coevolutionary chemical arms races has arisen multiple times throughout animalia. Prior documentation of resistance to snake venom α-neurotoxins consists of the N-glycosylation motif or the hypothesized introduction of arginine at positions 187 at the α-1 nicotinic acetylcholine receptor orthosteric site. However, no further studies have investigated the possibility of other potential forms of resistance. Using a biolayer interferometry assay, we first confirm that the previously hypothesized resistance conferred by arginine at position 187 in the honey badger does reduce binding to α-neurotoxins, which has never been functionally tested. We further discovered a novel form of α-neurotoxin resistance conferred by charge reversal mutations, whereby a negatively charged amino acid is replaced by the positively charged amino acid lysine. As venom α-neurotoxins have evolved strong positive charges on their surface to facilitate binding to the negatively charged α-1 orthosteric site, these mutations result in a positive charge/positive charge interaction electrostatically repelling the α-neurotoxins. Such a novel mechanism for resistance has gone completely undiscovered, yet this form of resistance has convergently evolved at least 10 times within snakes. These coevolutionary innovations seem to have arisen through convergent phenotypes to ultimately evolve a similar biophysical mechanism of resistance across snakes.
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Affiliation(s)
- Richard J Harris
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Bryan G Fry
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
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14
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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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15
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Whitelaw BL, Cooke IR, Finn J, da Fonseca RR, Ritschard EA, Gilbert MTP, Simakov O, Strugnell JM. Adaptive venom evolution and toxicity in octopods is driven by extensive novel gene formation, expansion, and loss. Gigascience 2020; 9:giaa120. [PMID: 33175168 PMCID: PMC7656900 DOI: 10.1093/gigascience/giaa120] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/10/2020] [Accepted: 10/06/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Cephalopods represent a rich system for investigating the genetic basis underlying organismal novelties. This diverse group of specialized predators has evolved many adaptations including proteinaceous venom. Of particular interest is the blue-ringed octopus genus (Hapalochlaena), which are the only octopods known to store large quantities of the potent neurotoxin, tetrodotoxin, within their tissues and venom gland. FINDINGS To reveal genomic correlates of organismal novelties, we conducted a comparative study of 3 octopod genomes, including the Southern blue-ringed octopus (Hapalochlaena maculosa). We present the genome of this species and reveal highly dynamic evolutionary patterns at both non-coding and coding organizational levels. Gene family expansions previously reported in Octopus bimaculoides (e.g., zinc finger and cadherins, both associated with neural functions), as well as formation of novel gene families, dominate the genomic landscape in all octopods. Examination of tissue-specific genes in the posterior salivary gland revealed that expression was dominated by serine proteases in non-tetrodotoxin-bearing octopods, while this family was a minor component in H. maculosa. Moreover, voltage-gated sodium channels in H. maculosa contain a resistance mutation found in pufferfish and garter snakes, which is exclusive to the genus. Analysis of the posterior salivary gland microbiome revealed a diverse array of bacterial species, including genera that can produce tetrodotoxin, suggestive of a possible production source. CONCLUSIONS We present the first tetrodotoxin-bearing octopod genome H. maculosa, which displays lineage-specific adaptations to tetrodotoxin acquisition. This genome, along with other recently published cephalopod genomes, represents a valuable resource from which future work could advance our understanding of the evolution of genomic novelty in this family.
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Affiliation(s)
- Brooke L Whitelaw
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, 1 James Cook Dr, Douglas QLD 4811 , Australia
- Sciences, Museum Victoria, 11 Nicholson St, Carlton, Victoria 3053, Australia
| | - Ira R Cooke
- College of Public Health, Medical and Vet Sciences, James Cook University,1 James Cook Dr, Douglas QLD 4811 , Australia
- La Trobe Institute of Molecular Science, La Trobe University, Plenty Rd &, Kingsbury Dr, Bundoora, Melbourne, Victoria 3086, Australia
| | - Julian Finn
- Sciences, Museum Victoria, 11 Nicholson St, Carlton, Victoria 3053, Australia
| | - Rute R da Fonseca
- Center for Macroecology, Evolution and Climate (CMEC), GLOBE Institute, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Elena A Ritschard
- Department of Neurosciences and Developmental Biology, University of Vienna,Universitätsring 1, 1010 Wien, Vienna, Austria
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - M T P Gilbert
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen, Denmark
| | - Oleg Simakov
- Department of Neurosciences and Developmental Biology, University of Vienna,Universitätsring 1, 1010 Wien, Vienna, Austria
| | - Jan M Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, 1 James Cook Dr, Douglas QLD 4811 , Australia
- Department of Ecology, Environment and Evolution, La Trobe University, Plenty Rd &, Kingsbury Dr, Bundoora, Melbourne, Victoria 3086, Australia
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16
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Sousa LF, Bernardoni JL, Zdenek CN, Dobson J, Coimbra F, Gillett A, Lopes-Ferreira M, Moura-da-Silva AM, Fry BG. Differential coagulotoxicity of metalloprotease isoforms from Bothrops neuwiedi snake venom and consequent variations in antivenom efficacy. Toxicol Lett 2020; 333:211-221. [PMID: 32841740 DOI: 10.1016/j.toxlet.2020.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022]
Abstract
Bothrops (lance-head pit vipers) venoms are rich in weaponised metalloprotease enzymes (SVMP). These toxic enzymes are structurally diverse and functionally versatile. Potent coagulotoxicity is particularly important for prey capture (via stroke-induction) and relevant to human clinical cases (due to consumption of clotting factors including the critical depletion of fibrinogen). In this study, three distinct isoforms of P-III class SVMPs (IC, IIB and IIC), isolated from Bothrops neuwiedi venom, were evaluated for their differential capacities to affect hemostasis of prey and human plasma. Furthermore, we tested the relative antivenom neutralisation of effects upon human plasma. The toxic enzymes displayed differential procoagulant potency between plasma types, and clinically relevant antivenom efficacy variations were observed. Of particular importance was the confirmation the antivenom performed better against prothrombin activating toxins than Factor X activating toxins, which is likely due to the greater prevalence of the former in the immunising venoms used for antivenom production. This is clinically relevant as the enzymes displayed differential potency in this regard, with one (IC) in particular being extremely potent in activating Factor X and thus was correspondingly poorly neutralised. This study broadens the current understanding about the adaptive role of the SVMPs, as well as highlights how the functional diversity of SVMP isoforms can influence clinical outcomes. Key Contribution: Our findings shed light upon the hemorrhagic and coagulotoxic effects of three SVMPs of the P-III class, as well as the coagulotoxic effects of SVMPs on human, avian and amphibian plasmas. Antivenom neutralised prothrombin-activating isoforms better than Factor X activating isoforms.
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Affiliation(s)
- Leijiane F Sousa
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo, SP, Brazil; Toxin Evolution Lab, School of Biological Sciences, University of Queensland, Santa Lucia, QLD 4072, Australia
| | | | - Christina N Zdenek
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, Santa Lucia, QLD 4072, Australia
| | - James Dobson
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, Santa Lucia, QLD 4072, Australia
| | - Francisco Coimbra
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, Santa Lucia, QLD 4072, Australia
| | - Amber Gillett
- Fauna Vet Wildlife Veterinary Consultancy, Beerwah, QLD, Australia
| | - Mônica Lopes-Ferreira
- Immunoregulation Unit of the Special Laboratory of Applied Toxinology (Center of Toxins Immune-Response and Cell Signaling), Butantan Institute, São Paulo, SP, Brazil
| | - A M Moura-da-Silva
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo, SP, Brazil.
| | - Bryan G Fry
- Toxin Evolution Lab, School of Biological Sciences, University of Queensland, Santa Lucia, QLD 4072, Australia.
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17
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Vivas-Ruiz DE, Sandoval GA, Gonzalez-Kozlova E, Zarria-Romero J, Lazo F, Rodríguez E, Magalhães HPB, Chávez-Olortegui C, Oliveira LS, Alvarenga VG, Urra FA, Toledo J, Yarlequé A, Eble JA, Sanchez EF. Fibrinogen-clotting enzyme, pictobin, from Bothrops pictus snake venom. Structural and functional characterization. Int J Biol Macromol 2020; 153:779-795. [PMID: 32169454 DOI: 10.1016/j.ijbiomac.2020.03.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/09/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022]
Abstract
A thrombin-like enzyme, pictobin, was purified from Bothrops pictus snake venom. It is a 41-kDa monomeric glycoprotein as showed by mass spectrometry and contains approx. 45% carbohydrate by mass which could be removed with N-glycosidase. Pictobin coagulates plasma and fibrinogen, releasing fibrinopeptide A and induces the formation of a friable/porous fibrin network as visualized by SEM. The enzyme promoted platelet aggregation in human PRP and defibrination in mouse model and showed catalytic activity on chromogenic substrates S-2266, S-2366, S-2160 and S-2238. Pictobin interacts with the plasma inhibitor α2-macroglobulin, which blocks its interaction with fibrinogen but not with the small substrate BApNA. Heparin does not affect its enzymatic activity. Pictobin cross reacted with polyvalent bothropic antivenom, and its deglycosylated form reduced its catalytic action and antivenom reaction. In breast and lung cancer cells, pictobin inhibits the fibronectin-stimulated migration. Moreover, it produces strong NADH oxidation, mitochondrial depolarization, ATP decrease and fragmentation of mitochondrial network. These results suggest by first time that a snake venom serinprotease produces mitochondrial dysfunction by affecting mitochondrial dynamics and bioenergetics. Structural model of pictobin reveals a conserved chymotrypsin fold β/β hydrolase. These data indicate that pictobin has therapeutic potential in the treatment of cardiovascular disorders and metastatic disease.
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Affiliation(s)
- Dan E Vivas-Ruiz
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru.
| | - Gustavo A Sandoval
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru
| | - Edgar Gonzalez-Kozlova
- Department of Genetics and Genomic Sciences, Icahn School for Data Science and Genomic Technology, New York, NYC, USA
| | - Jacquelyne Zarria-Romero
- Laboratorio de Reproducción y Biología del Desarrollo, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela ra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru
| | - Fanny Lazo
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru
| | - Edith Rodríguez
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru
| | - Henrique P B Magalhães
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil
| | - Carlos Chávez-Olortegui
- Departamento de Bioquímica-Inmunología, Instituto de Ciências Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil
| | - Luciana S Oliveira
- Research and Development Center, Ezequiel Dias Foundation, 30510-010 Belo Horizonte, MG, Brazil
| | - Valeria G Alvarenga
- Research and Development Center, Ezequiel Dias Foundation, 30510-010 Belo Horizonte, MG, Brazil
| | - Félix A Urra
- Programa de Farmacología Clínica y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, Casilla 7, Santiago 7800003, Chile
| | - Jorge Toledo
- Instituto de Neurociencia Biomédica, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile; Facultad de Ciencias de la Salud, Universidad San Sebastián, Lota 2465, Providencia, Santiago 7510157, Chile
| | - Armando Yarlequé
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 01, Lima, Peru
| | - Johannes A Eble
- Institute for Physiological Chemistry and Pathobiochemistry, University of Münster, 48149 Münster, Germany
| | - Eladio F Sanchez
- Research and Development Center, Ezequiel Dias Foundation, 30510-010 Belo Horizonte, MG, Brazil
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18
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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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19
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Bocian A, Sławek S, Jaromin M, Hus KK, Buczkowicz J, Łysiak D, Petrílla V, Petrillova M, Legáth J. Comparison of Methods for Measuring Protein Concentration in Venom Samples. Animals (Basel) 2020; 10:E448. [PMID: 32182656 PMCID: PMC7142616 DOI: 10.3390/ani10030448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 01/15/2023] Open
Abstract
Snake venom is an extremely interesting natural mixture of proteins and peptides, characterized by both high diversity and high pharmacological potential. Much attention has been paid to the study of venom composition of different species and also detailed analysis of the properties of individual components. Since proteins and peptides are the active ingredients in venom, rapidly developing proteomic techniques are used to analyze them. During such analyses, one of the routine operations is to measure the protein concentration in the sample. The aim of this study was to compare five methods used to measure protein content in venoms of two snake species: the Viperids representative, Agkistrodon contortrix, and the Elapids representative, Naja ashei. The study showed that for A. contortrix venom, the concentration of venom protein measured by four methods is very similar and only the NanoDrop method clearly stands out from the rest. However, in the case of N. ashei venom, each technique yields significantly different results. We hope that this report will help to draw attention to the problem of measuring protein concentration, especially in such a complex mixture as animal venoms.
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Affiliation(s)
- Aleksandra Bocian
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Sonja Sławek
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Marcin Jaromin
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Konrad K. Hus
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Justyna Buczkowicz
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Dawid Łysiak
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
| | - Vladimir Petrílla
- Department of Anatomy, Histology and Physiology, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Kosice, Slovakia;
- Zoological Department, Zoological Garden Košice, Široká 31, 040 06 Košice-Kavečany, Slovakia
| | - Monika Petrillova
- Department of General Education Subjects, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Kosice, Slovakia;
| | - Jaroslav Legáth
- Faculty of Chemistry, Rzeszow University of Technology, 35-959 Rzeszów, Poland; (S.S.); (M.J.); (K.K.H.); (J.B.); (D.Ł.)
- Department of Pharmacology and Toxicology, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Kosice, Slovakia
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Grashof D, Zdenek CN, Dobson JS, Youngman NJ, Coimbra F, Benard-Valle M, Alagon A, Fry BG. A Web of Coagulotoxicity: Failure of Antivenom to Neutralize the Destructive (Non-Clotting) Fibrinogenolytic Activity of Loxosceles and Sicarius Spider Venoms. Toxins (Basel) 2020; 12:toxins12020091. [PMID: 32019058 PMCID: PMC7076800 DOI: 10.3390/toxins12020091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/14/2020] [Accepted: 01/22/2020] [Indexed: 12/14/2022] Open
Abstract
Envenomations are complex medical emergencies that can have a range of symptoms and sequelae. The only specific, scientifically-validated treatment for envenomation is antivenom administration, which is designed to alleviate venom effects. A paucity of efficacy testing exists for numerous antivenoms worldwide, and understanding venom effects and venom potency can help identify antivenom improvement options. Some spider venoms can produce debilitating injuries or even death, yet have been largely neglected in venom and antivenom studies because of the low venom yields. Coagulation disturbances have been particularly under studied due to difficulties in working with blood and the coagulation cascade. These circumstances have resulted in suboptimal spider bite treatment for medically significant spider genera such as Loxosceles and Sicarius. This study identifies and quantifies the anticoagulant effects produced by venoms of three Loxoscles species (L. reclusa, L. boneti, and L. laeta) and that of Sicarius terrosus. We showed that the venoms of all studied species are able to cleave the fibrinogen Aα-chain with varying degrees of potency, with L. reclusa and S. terrosus venom cleaving the Aα-chain most rapidly. Thromboelastography analysis revealed that only L. reclusa venom is able to reduce clot strength, thereby presumably causing anticoagulant effects in the patient. Using the same thromboelastography assays, antivenom efficacy tests revealed that the commonly used Loxoscles-specific SMase D recombinant based antivenom failed to neutralize the anticoagulant effects produced by Loxosceles venom. This study demonstrates the fibrinogenolytic activity of Loxosceles and Sicarius venom and the neutralization failure of Loxosceles antivenom, thus providing impetus for antivenom improvement.
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Affiliation(s)
- Dwin Grashof
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
| | - Christina N. Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
| | - James S. Dobson
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
| | - Nicholas J. Youngman
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
| | - Francisco Coimbra
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
| | - Melisa Benard-Valle
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico; (M.B.-V.); (A.A.)
| | - Alejandro Alagon
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico; (M.B.-V.); (A.A.)
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.G.); (C.N.Z.); (J.S.D.); (N.J.Y.); (F.C.)
- Correspondence:
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21
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Debono J, Dashevsky D, Nouwens A, Fry BG. The sweet side of venom: Glycosylated prothrombin activating metalloproteases from Dispholidus typus (boomslang) and Thelotornis mossambicanus (twig snake). Comp Biochem Physiol C Toxicol Pharmacol 2020; 227:108625. [PMID: 31634575 DOI: 10.1016/j.cbpc.2019.108625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/13/2022]
Abstract
Dispholidus typus and Thelotornis mossambicanus are closely related rear-fanged colubrid snakes that both possess strongly procoagulant venoms. However, despite similarities in overall venom biochemistry and resulting clinical manifestations, the underlying venom composition differs significantly between the two species. As a result, the only available antivenom-which is a monovalent antivenom for D. typus-has minimal cross reactivity with T. mossambicanus and is not a clinically viable option. It was hypothesised that this lack of cross reactivity is due to the additional large metalloprotease protein within T. mossambicanus venom, which may also be responsible for faster coagulation times. In this study, we found that T. mossambicanus venom is a more powerful activator of prothrombin than that of D. typus and that the SVMP transcripts from T. mossambicanus form a clade with those from D. typus. The sequences from D. typus and T. mossambicanus were highly similar in length, with the calculated molecular weights of the T. mossambicanus transcripts being significantly less than the molecular weights of some isoforms on the 1D SDS-PAGE gels. Analyses utilising degylcosylating enzymes revealed that T. mossambicanus SVMPs are glycosylated during post-translational modification, but that this does not lead to the different molecular weight bands observed in 1D SDS-PAGE gels. However, differences in glycosylation patterns may still explain some of the difference between the enzymatic activities and neutralization by antivenom that have been observed in these venoms. The results of this study provide new information regarding the treatment options for patients envenomated by T. mossambicanus as well as the evolution of these dangerous snakes.
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Affiliation(s)
- Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Daniel Dashevsky
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Amanda Nouwens
- School of Chemistry and Molecular Biosciences, 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.
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Debono J, Bos MHA, Do MS, Fry BG. Clinical implications of coagulotoxic variations in Mamushi (Viperidae: Gloydius) snake venoms. Comp Biochem Physiol C Toxicol Pharmacol 2019; 225:108567. [PMID: 31306806 DOI: 10.1016/j.cbpc.2019.108567] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/24/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022]
Abstract
Snake bite is currently one of the most neglected tropical diseases affecting much of the developing world. Asian pit vipers are responsible for a considerable amount of envenomations annually and bites can cause a multitude of clinical complications resulting from coagulopathic and neuropathic effects. While intense research has been undertaken for some species of Asian pit viper, functional coagulopathic effects have been neglected for others. We investigated their effects upon the human clotting cascade using venoms of four species of Gloydius and Ovophis okinavensis, a species closely to Gloydius. All species of included within this investigation displayed varying fibrinogenolytic effects, resulting in a net anticoagulant outcome. Gloydius saxatilis and Gloydius ussuriensis displayed the most variable effects from differing localities, sampled from Russia and Korea. As this Gloydius investigation includes some geographical variation, notable results indicate key variations of these species that point to possible limitations in antivenom cross-reactivities, which may have implications for the clinical care of victims envenomed by these snakes.
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Affiliation(s)
- Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Min Seock Do
- Animal Ecology Lab, Department of Biology, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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23
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Zdenek CN, den Brouw BO, Dashevsky D, Gloria A, Youngman NJ, Watson E, Green P, Hay C, Dunstan N, Allen L, Fry BG. Clinical implications of convergent procoagulant toxicity and differential antivenom efficacy in Australian elapid snake venoms. Toxicol Lett 2019; 316:171-182. [DOI: 10.1016/j.toxlet.2019.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 10/26/2022]
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Debono J, Bos MHA, Frank N, Fry B. Clinical implications of differential antivenom efficacy in neutralising coagulotoxicity produced by venoms from species within the arboreal viperid snake genus Trimeresurus. Toxicol Lett 2019; 316:35-48. [PMID: 31509773 DOI: 10.1016/j.toxlet.2019.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/04/2019] [Accepted: 09/06/2019] [Indexed: 12/12/2022]
Abstract
Snake envenomation globally is attributed to an ever-increasing human population encroaching into snake territories. Responsible for many bites in Asia is the widespread genus Trimeresurus. While bites lead to haemorrhage, only a few species have had their venoms examined in detail. We found that Trimeresurus venom causes haemorrhaging by cleaving fibrinogen in a pseudo-procoagulation manner to produce weak, unstable, short-lived fibrin clots ultimately resulting in an overall anticoagulant effect due to fibrinogen depletion. The monovalent antivenom 'Thai Red Cross Green Pit Viper antivenin', varied in efficacy ranging from excellent neutralisation of T. albolabris venom through to T. gumprechti and T. mcgregori being poorly neutralised and T. hageni being unrecognised by the antivenom. While the results showing excellent neutralisation of some non-T. albolabris venoms (such as T. flavomaculaturs, T. fucatus, and T. macrops) needs to be confirmed with in vivo tests, conversely the antivenom failure T. hageni, and the very poor results against T. gumprechti and T. mcgregori, despite being conducted in the ideal scenario of preincubation of antivenom:venom, indicates that the likelihood of clinically relevant cross-reactivity for these species is low (T. gumprechti and T. mcgregori) to non-existent (T. hageni). These same latter three species were also not inhibited by the serine protease inhibitor AEBSF, suggesting that the toxins leading to a coagulotoxic effect in these species are non-serine proteases while in contrast T. albolabris coagulotoxicity was completely impeded by AEBSF, and thus driven by kallikrein-type serine proteases. There was a conspicuous lack of phylogenetic pattern in venom variation, with the most potent venoms (T. albolabris and T. hageni) being distant to each other on the organismal tree, and with the three most divergent and poorly neutralised venoms (T. gumprechti, T. hageni, and T. mcgregori) were also not each others closest relatives. This reinforces the paradigm that the fundamental dynamic evolution of venom results in organismal phylogeny being a poor predictor of venom potency or antivenom efficacy. This study provides a robust investigation on the differential venom effects from a wide range of Trimeresurus species on coagulation, highlighting differential fibrinogenolytic effects, while also investigating the relative antivenom neutralisation capabilities of the widely available Thai Red Cross Green Pit Viper antivenom. These results therefore have immediate, real-world implications for patients envenomed by Trimeresurus species.
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Affiliation(s)
- Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, the Netherlands
| | | | - Bryan 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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Venomous Landmines: Clinical Implications of Extreme Coagulotoxic Diversification and Differential Neutralization by Antivenom of Venoms within the Viperid Snake Genus Bitis. Toxins (Basel) 2019; 11:toxins11070422. [PMID: 31331004 PMCID: PMC6669450 DOI: 10.3390/toxins11070422] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 12/29/2022] Open
Abstract
The genus Bitis comprises 17 snake species that inhabit Africa and the Arabian Peninsula. They are responsible for a significant proportion of snakebites in the region. The venoms of the two independent lineages of giant Bitis (B. arietans and again in the common ancestor of the clade consisting of B. gabonica, B. nasicornis, B. parviocula and B. rhinoceros) induce an array of debilitating effects including anticoagulation, hemorrhagic shock and cytotoxicity, whilst the dwarf species B. atropos is known to have strong neurotoxic effects. However, the venom effects of the other species within the genus have not been explored in detail. A series of coagulation assays were implemented to assess the coagulotoxic venom effects of fourteen species within the genus. This study identified procoagulant venom as the ancestral condition, retained only by the basal dwarf species B. worthingtoni, suggesting anticoagulant venom is a derived trait within the Bitis genus and has been secondarily amplified on at least four occasions. A wide range of anticoagulant mechanisms were identified, such as coagulant and destructive activities upon fibrinogen in both giant and dwarf Bitis and the action of inhibiting the prothrombinase complex, which is present in a clade of dwarf Bitis. Antivenom studies revealed that while the procoagulant effects of B. worthingtoni were poorly neutralized, and thus a cause for concern, the differential mechanisms of anticoagulation in other species were all well neutralized. Thus, this study concludes there is a wide range of coagulotoxic mechanisms which have evolved within the Bitis genus and that clinical management strategies are limited for the procoagulant effects of B. worthingtoni, but that anticoagulant effects of other species are readily treated by the South African polyvalent antivenom. These results therefore have direct, real-work implications for the treatment of envenomed patients.
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Dobson JS, Zdenek CN, Hay C, Violette A, Fourmy R, Cochran C, Fry BG. Varanid Lizard Venoms Disrupt the Clotting Ability of Human Fibrinogen through Destructive Cleavage. Toxins (Basel) 2019; 11:E255. [PMID: 31067768 PMCID: PMC6563220 DOI: 10.3390/toxins11050255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023] Open
Abstract
The functional activities of Anguimorpha lizard venoms have received less attention compared to serpent lineages. Bite victims of varanid lizards often report persistent bleeding exceeding that expected for the mechanical damage of the bite. Research to date has identified the blockage of platelet aggregation as one bleeding-inducing activity, and destructive cleavage of fibrinogen as another. However, the ability of the venoms to prevent clot formation has not been directly investigated. Using a thromboelastograph (TEG5000), clot strength was measured after incubating human fibrinogen with Heloderma and Varanus lizard venoms. Clot strengths were found to be highly variable, with the most potent effects produced by incubation with Varanus venoms from the Odatria and Euprepriosaurus clades. The most fibrinogenolytically active venoms belonged to arboreal species and therefore prey escape potential is likely a strong evolutionary selection pressure. The results are also consistent with reports of profusive bleeding from bites from other notably fibrinogenolytic species, such as V. giganteus. Our results provide evidence in favour of the predatory role of venom in varanid lizards, thus shedding light on the evolution of venom in reptiles and revealing potential new sources of bioactive molecules useful as lead compounds in drug design and development.
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Affiliation(s)
- James S Dobson
- 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.
| | - Chris Hay
- 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.
| | - Chip Cochran
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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27
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Duarte RCF, Rios DRA, Leite PM, Alves LC, Magalhães HPB, Carvalho MDG. Thrombin generation test for evaluating hemostatic effects of Brazilian snake venoms. Toxicon 2019; 163:36-43. [DOI: 10.1016/j.toxicon.2019.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/11/2019] [Accepted: 03/12/2019] [Indexed: 12/01/2022]
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28
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Debono J, Bos MHA, Coimbra F, Ge L, Frank N, Kwok HF, Fry BG. Basal but divergent: Clinical implications of differential coagulotoxicity in a clade of Asian vipers. Toxicol In Vitro 2019; 58:195-206. [PMID: 30930232 DOI: 10.1016/j.tiv.2019.03.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 01/06/2023]
Abstract
Envenomations by Asian pitvipers can induce multiple clinical complications resulting from coagulopathic and neuropathic effects. While intense research has been undertaken for some species, functional coagulopathic effects have been neglected. As these species' venoms affect the blood coagulation cascade we investigated their effects upon the human clotting cascade using venoms of species from the Azemiops, Calloselasma, Deinagkistrodon and Hypnale genera. Calloselasma rhodostoma, Deinagkistrodon acutus, and Hypnale hypnale produced net anticoagulant effects through pseudo-procoagulant clotting of fibrinogen, resulting in weak, unstable, transient fibrin clots. Tropidolaemus wagleri was only weakly pseudo-procoagulant, clotting fibrinogen with only a negligible net anticoagulant effect. Azemiops feae and Tropidolaemus subannulatus did not affect clotting. This is the first study to examine in a phylogenetic context the coagulotoxic effects of related genera of basal Asiatic pit-vipers. The results reveal substantial variation between sister genera, providing crucial information about clinical effects and implications for antivenom cross-reactivity.
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Affiliation(s)
- Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, the Netherlands
| | - Francisco Coimbra
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Lilin Ge
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau; State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Pharmacy, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Qixia District, Nanjing 210046, China
| | | | - Hang Fai Kwok
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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29
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Zdenek CN, Hay C, Arbuckle K, Jackson TNW, Bos MHA, Op den Brouw B, Debono J, Allen L, Dunstan N, Morley T, Herrera M, Gutiérrez JM, Williams DJ, Fry BG. Coagulotoxic effects by brown snake (Pseudonaja) and taipan (Oxyuranus) venoms, and the efficacy of a new antivenom. Toxicol In Vitro 2019; 58:97-109. [PMID: 30910521 DOI: 10.1016/j.tiv.2019.03.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 01/03/2023]
Abstract
Snakebite is a neglected tropical disease that disproportionately affects the poor. Antivenom is the only specific and effective treatment for snakebite, but its distribution is severely limited by several factors, including the prohibitive cost of some products. Papua New Guinea (PNG) is a snakebite hotspot but the high costs of Australian antivenoms (thousands of dollars per treatment) makes it unaffordable in PNG. A more economical taipan antivenom has recently been developed at the Instituto Clodomiro Picado (ICP) in Costa Rica for PNG and is currently undergoing clinical trials for the treatment of envenomations by coastal taipans (Oxyuranus scutellatus). In addition to potentially having the capacity to neutralise the effects of envenomations of non-PNG taipans, this antivenom may have the capacity to neutralise coagulotoxins in venom from closely related brown snakes (Pseudonaja spp.) also found in PNG. Consequently, we investigated the cross-reactivity of taipan antivenom across the venoms of all Oxyuranus and Pseudonaja species. In addition, to ascertain differences in venom biochemistry that influence variation in antivenom efficacy, we tested for relative cofactor dependence. We found that the new ICP taipan antivenom exhibited high selectivity for Oxyuranus venoms and only low to moderate cross-reactivity with any Pseudonaja venoms. Consistent with this genus level distinction in antivenom efficacy were fundamental differences in the venom biochemistry. Not only were the Pseudonaja venoms significantly more procoagulant, but they were also much less dependent upon the cofactors calcium and phospholipid. There was a strong correlation between antivenom efficacy, clotting time and cofactor dependence. This study sheds light on the structure-function relationships of the procoagulant toxins within these venoms and may have important clinical implications including for the design of next-generation antivenoms.
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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
| | - Chris Hay
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Reptile Kingdom Australia, Carrara, QLD, Australia
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, SA2 8PP, United Kingdom
| | - Timothy N W Jackson
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, the Netherlands
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | | | - María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - José M Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - David J Williams
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia; Charles Campbell Toxinology Centre, School of Medicine and Health Sciences, University of Papua New Guinea, Boroko 121, National Capital District, Papua New Guinea
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
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Debono J, Bos MHA, Nouwens A, Ge L, Frank N, Kwok HF, Fry BG. Habu coagulotoxicity: Clinical implications of the functional diversification of Protobothrops snake venoms upon blood clotting factors. Toxicol In Vitro 2018; 55:62-74. [PMID: 30471431 DOI: 10.1016/j.tiv.2018.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/24/2018] [Accepted: 11/20/2018] [Indexed: 01/19/2023]
Abstract
Venom can affect any part of the body reachable via the bloodstream. Toxins which specifically act upon the coagulation cascade do so either by anticoagulant or procoagulant mechanisms. Here we investigated the coagulotoxic effects of six species within the medically important pit viper genus Protobothrops (Habu) from the Chinese mainland and Japanese islands, a genus known to produce hemorrhagic shock in envenomed patients. Differential coagulotoxicity was revealed: P. jerdonii and P. mangshanensis produced an overall net anticoagulant effect through the pseudo-procoagulant clotting of fibrinogen; P. flavoviridis and P. tokarensis exhibit a strong anticoagulant activity through the destructive cleavage of fibrinogen; and while P. elegans and P. mucrosquamatus both cleaved the A-alpha and B-beta chains of fibrinogen they did not exhibit strong anticoagulant activity. These variations in coagulant properties were congruent with phylogeny, with the closest relatives exhibiting similar venom effects in their action upon fibrinogen. Ancestral state reconstruction indicated that anticoagulation mediated by pseudo-procoagulant cleavage of fibrinogen is the basal state, while anticoagulation produced by destructive cleavage of fibrinogen is the derived state within this genus. This is the first in depth study of its kind highlighting extreme enzymatic variability, functional diversification and clotting diversification within one genus surrounding one target site, governed by variability in co-factor dependency. The documentation that the same net overall function, anticoagulation, is mediated by differential underlying mechanics suggests limited antivenom cross-reactivity, although this must be tested in future work. These results add to the body of knowledge necessary to inform clinical management of the envenomed patient.
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Affiliation(s)
- Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, the Netherlands
| | - Amanda Nouwens
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia 4072, Australia
| | - Lilin Ge
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, China; Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Qixia District, Nanjing 215400, China
| | | | - Hang Fai Kwok
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau, China.
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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Coagulotoxicity of Bothrops (Lancehead Pit-Vipers) Venoms from Brazil: Differential Biochemistry and Antivenom Efficacy Resulting from Prey-Driven Venom Variation. Toxins (Basel) 2018; 10:toxins10100411. [PMID: 30314373 PMCID: PMC6215258 DOI: 10.3390/toxins10100411] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/03/2018] [Accepted: 10/08/2018] [Indexed: 01/10/2023] Open
Abstract
Lancehead pit-vipers (Bothrops genus) are an extremely diverse and medically important group responsible for the greatest number of snakebite envenomations and deaths in South America. Bothrops atrox (common lancehead), responsible for majority of snakebites and related deaths within the Brazilian Amazon, is a highly adaptable and widely distributed species, whose venom variability has been related to several factors, including geographical distribution and habitat type. This study examined venoms from four B. atrox populations (Belterra and Santarém, PA; Pres. Figueiredo, AM and São Bento, MA), and two additional Bothrops species (B. jararaca and B. neuwiedi) from Southeastern region for their coagulotoxic effects upon different plasmas (human, amphibian, and avian). The results revealed inter– and intraspecific variations in coagulotoxicity, including distinct activities between the three plasmas, with variations in the latter two linked to ecological niche occupied by the snakes. Also examined were the correlated biochemical mechanisms of venom action. Significant variation in the relative reliance upon the cofactors calcium and phospholipid were revealed, and the relative dependency did not significantly correlate with potency. Relative levels of Factor X or prothrombin activating toxins correlated with prey type and prey escape potential. The antivenom was shown to perform better in neutralising prothrombin activation activity than neutralising Factor X activation activity. Thus, the data reveal new information regarding the evolutionary selection pressures shaping snake venom evolution, while also having significant implications for the treatment of the envenomed patient. These results are, therefore, an intersection between evolutionary biology and clinical medicine.
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Three-Finger Toxin Diversification in the Venoms of Cat-Eye Snakes (Colubridae: Boiga). J Mol Evol 2018; 86:531-545. [PMID: 30206667 DOI: 10.1007/s00239-018-9864-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023]
Abstract
The Asian genus Boiga (Colubridae) is among the better studied non-front-fanged snake lineages, because their bites have minor, but noticeable, effects on humans. Furthermore, B. irregularis has gained worldwide notoriety for successfully invading Guam and other nearby islands with drastic impacts on the local bird populations. One of the factors thought to allow B. irregularis to become such a noxious pest is irditoxin, a dimeric neurotoxin composed of two three-finger toxins (3FTx) joined by a covalent bond between two newly evolved cysteines. Irditoxin is highly toxic to diapsid (birds and reptiles) prey, but roughly 1000 × less potent to synapsids (mammals). Venom plays an important role in the ecology of all species of Boiga, but it remains unknown if any species besides B. irregularis produce irditoxin-like dimeric toxins. In this study, we use transcriptomic analyses of venom glands from five species [B. cynodon, B. dendrophila dendrophila, B. d. gemmicincta, B. irregularis (Brisbane population), B. irregularis (Sulawesi population), B. nigriceps, B. trigonata] and proteomic analyses of B. d. dendrophila and a representative of the sister genus Toxicodryas blandingii to investigate the evolutionary history of 3FTx within Boiga and its close relative. We found that 92.5% of Boiga 3FTx belong to a single clade which we refer to as denmotoxin-like because of the close relation between these toxins and the monomeric denmotoxin according to phylogenetic, sequence clustering, and protein similarity network analyses. We show for the first time that species beyond B. irregularis secrete 3FTx with additional cysteines in the same position as both the A and B subunits of irditoxin. Transcripts with the characteristic mutations are found in B. d. dendrophila, B. d. gemmicincta, B. irregularis (Brisbane population), B. irregularis (Sulawesi population), and B. nigriceps. These results are confirmed by proteomic analyses that show direct evidence of dimerization within the venom of B. d. dendrophila, but not T. blandingii. Our results also suggest the possibility of novel dimeric toxins in other genera such as Telescopus and Trimorphodon. All together, this suggests that the origin of these peculiar 3FTx is far earlier than was appreciated and their evolutionary history has been complex.
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Nielsen VG, Frank N. Role of heme modulation in inhibition of Atheris, Atractaspis, Causus, Cerastes, Echis, and Macrovipera hemotoxic venom activity. Hum Exp Toxicol 2018; 38:216-226. [PMID: 30086669 DOI: 10.1177/0960327118793186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Venomous snake bite and subsequent coagulopathy is a significant source of morbidity and mortality worldwide. The gold standard to treat coagulopathy caused by these venoms is the administration of antivenom; however, despite this therapy, coagulopathy still occurs and recurs. Of interest, our laboratory has demonstrated in vitro and in vivo that coagulopathy-inducing venom exposed to carbon monoxide (CO) is inhibited, potentially by an attached heme. The present investigation sought to determine if venoms derived from snakes of the African genera Atheris, Atractaspis, Causus, Cerastes, Echis, and Macrovipera that have no or limited antivenoms available could be inhibited with CO or with the metheme-inducing agent, O-phenylhydroxylamine (PHA). Assessing changes in coagulation kinetics of human plasma with thrombelastography, venoms were exposed in isolation to CO or PHA. Eight species were found to have procoagulant activity consistent with the generation of human thrombin, while one was likely fibrinogenolytic. All venoms were significantly inhibited by CO/PHA with species-specific variation noted. These data demonstrate indirectly that the heme is likely bound to these disparate venoms as an intermediary modulatory molecule. In conclusion, future investigation is warranted to determine if heme could serve as a potential therapeutic target to be modulated during treatment of envenomation by hemotoxic enzymes.
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Affiliation(s)
- V G Nielsen
- 1 The Department of Anesthesiology, The University of Arizona College of Medicine, Tucson, AZ, USA
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Fry BG. Snakebite: When the Human Touch Becomes a Bad Touch. Toxins (Basel) 2018; 10:E170. [PMID: 29690533 PMCID: PMC5923336 DOI: 10.3390/toxins10040170] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 01/08/2023] Open
Abstract
Many issues and complications in treating snakebite are a result of poor human social, economic and clinical intervention and management. As such, there is scope for significant improvements for reducing incidence and increasing patient outcomes. Snakes do not target humans as prey, but as our dwellings and farms expand ever farther and climate change increases snake activity periods, accidental encounters with snakes seeking water and prey increase drastically. Despite its long history, the snakebite crisis is neglected, ignored, underestimated and fundamentally misunderstood. Tens of thousands of lives are lost to snakebites each year and hundreds of thousands of people will survive with some form of permanent damage and reduced work capacity. These numbers are well recognized as being gross underestimations due to poor to non-existent record keeping in some of the most affected areas. These underestimations complicate achieving the proper recognition of snakebite’s socioeconomic impact and thus securing foreign aid to help alleviate this global crisis. Antivenoms are expensive and hospitals are few and far between, leaving people to seek help from traditional healers or use other forms of ineffective treatment. In some cases, cheaper, inappropriately manufactured antivenom from other regions is used despite no evidence for their efficacy, with often robust data demonstrating they are woefully ineffective in neutralizing many venoms for which they are marketed for. Inappropriate first-aid and treatments include cutting the wound, tourniquets, electrical shock, immersion in ice water, and use of ineffective herbal remedies by traditional healers. Even in the developed world, there are fundamental controversies including fasciotomy, pressure bandages, antivenom dosage, premedication such as adrenalin, and lack of antivenom for exotic snakebites in the pet trade. This review explores the myriad of human-origin factors that influence the trajectory of global snakebite causes and treatment failures and illustrate that snakebite is as much a sociological and economic problem as it is a medical one. Reducing the incidence and frequency of such controllable factors are therefore realistic targets to help alleviate the global snakebite burden as incremental improvements across several areas will have a strong cumulative effect.
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Affiliation(s)
- Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia.
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