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Calvete JJ, Lomonte B, Tena-Garcés J, Zollweg M, Mebs D. Mandibular gland proteomics of the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, Abronia lythrochila. Toxicon 2024; 249:108055. [PMID: 39097104 DOI: 10.1016/j.toxicon.2024.108055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/05/2024]
Abstract
A useful approach to deepen our knowledge about the origin and evolution of venom systems in Reptilia has been exploring the vast biodiversity of this clade of vertebrates in search of orally produced proteins with toxic actions, as well as their corresponding delivery systems. The occurrence of toxins in anguimorph lizards has been demonstrated experimentally or inferred from reports of the toxic effects of the oral secretions of taxa within the Varanidae and Helodermatidae families. In the present study, we have focused on two alligator lizards of the Anguidae family, the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, A. lythrochila. In addition, the fine morphology of teeth of the latter species is described. The presence of a conserved set of proteins, including B-type natriuretic peptides, cysteine-rich secretory proteins, group III phospholipase A2, and kallikrein, in submandibular gland extracts was demonstrated for both Abronia species. These proteins belong to toxin families found in oral gland secretions of venomous reptile species. This finding, along with previous demonstration of toxin-producing taxa in both paleo- and neoanguimorpha clades, provides further support for the existence of a handful of conserved toxin families in oral secretions across the 100+ million years of Anguimorpha cladogenesis.
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Affiliation(s)
- Juan J Calvete
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, C.S.I.C., Jaime Roig 11, 46010, Valencia, Spain.
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica, San José, 11501, Costa Rica.
| | - Jordi Tena-Garcés
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, C.S.I.C., Jaime Roig 11, 46010, Valencia, Spain.
| | | | - Dietrich Mebs
- Institute of Legal Medicine, Goethe University of Frankfurt, Kennedyallee 104, D-60569, Frankfurt, Germany.
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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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Coelho GR, da Silva DL, Beraldo-Neto E, Vigerelli H, de Oliveira LA, Sciani JM, Pimenta DC. Neglected Venomous Animals and Toxins: Underrated Biotechnological Tools in Drug Development. Toxins (Basel) 2021; 13:toxins13120851. [PMID: 34941689 PMCID: PMC8708286 DOI: 10.3390/toxins13120851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 12/15/2022] Open
Abstract
Among the vast repertoire of animal toxins and venoms selected by nature and evolution, mankind opted to devote its scientific attention—during the last century—to a restricted group of animals, leaving a myriad of toxic creatures aside. There are several underlying and justifiable reasons for this, which include dealing with the public health problems caused by envenoming by such animals. However, these studies became saturated and gave rise to a whole group of animals that become neglected regarding their venoms and secretions. This repertoire of unexplored toxins and venoms bears biotechnological potential, including the development of new technologies, therapeutic agents and diagnostic tools and must, therefore, be assessed. In this review, we will approach such topics through an interconnected historical and scientific perspective that will bring up the major discoveries and innovations in toxinology, achieved by researchers from the Butantan Institute and others, and describe some of the major research outcomes from the study of these neglected animals.
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Affiliation(s)
- Guilherme Rabelo Coelho
- Laboratório de Bioquímica, Instituto Butantan, São Paulo 05503-900, Brazil; (G.R.C.); (D.L.d.S.); (E.B.-N.)
| | - Daiane Laise da Silva
- Laboratório de Bioquímica, Instituto Butantan, São Paulo 05503-900, Brazil; (G.R.C.); (D.L.d.S.); (E.B.-N.)
| | - Emidio Beraldo-Neto
- Laboratório de Bioquímica, Instituto Butantan, São Paulo 05503-900, Brazil; (G.R.C.); (D.L.d.S.); (E.B.-N.)
| | - Hugo Vigerelli
- Laboratório de Genética, Instituto Butantan, São Paulo 05503-900, Brazil;
| | - Laudiceia Alves de Oliveira
- Laboratório de Moléstias Infecciosas—Faculdade de Medicina de Botucatu, São Paulo State University (UNESP), São Paulo 01049-010, Brazil;
| | - Juliana Mozer Sciani
- Laboratório Multidisciplinar em Pesquisa, Universidade São Francisco, Bragança Paulista 12916-900, Brazil;
| | - Daniel Carvalho Pimenta
- Laboratório de Bioquímica, Instituto Butantan, São Paulo 05503-900, Brazil; (G.R.C.); (D.L.d.S.); (E.B.-N.)
- Correspondence:
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Dobson JS, Harris RJ, Zdenek CN, Huynh T, Hodgson WC, Bosmans F, Fourmy R, Violette A, Fry BG. The Dragon's Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms. Toxins (Basel) 2021; 13:toxins13080549. [PMID: 34437420 PMCID: PMC8402328 DOI: 10.3390/toxins13080549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/19/2022] Open
Abstract
Bites from helodermatid lizards can cause pain, paresthesia, paralysis, and tachycardia, as well as other symptoms consistent with neurotoxicity. Furthermore, in vitro studies have shown that Heloderma horridum venom inhibits ion flux and blocks the electrical stimulation of skeletal muscles. Helodermatids have long been considered the only venomous lizards, but a large body of robust evidence has demonstrated venom to be a basal trait of Anguimorpha. This clade includes varanid lizards, whose bites have been reported to cause anticoagulation, pain, and occasionally paralysis and tachycardia. Despite the evolutionary novelty of these lizard venoms, their neuromuscular targets have yet to be identified, even for the iconic helodermatid lizards. Therefore, to fill this knowledge gap, the venoms of three Heloderma species (H. exasperatum, H. horridum and H. suspectum) and two Varanus species (V. salvadorii and V. varius) were investigated using Gallus gallus chick biventer cervicis nerve–muscle preparations and biolayer interferometry assays for binding to mammalian ion channels. Incubation with Heloderma venoms caused the reduction in nerve-mediated muscle twitches post initial response of avian skeletal muscle tissue preparation assays suggesting voltage-gated sodium (NaV) channel binding. Congruent with the flaccid paralysis inducing blockage of electrical stimulation in the skeletal muscle preparations, the biolayer interferometry tests with Heloderma suspectum venom revealed binding to the S3–S4 loop within voltage-sensing domain IV of the skeletal muscle channel subtype, NaV1.4. Consistent with tachycardia reported in clinical cases, the venom also bound to voltage-sensing domain IV of the cardiac smooth muscle calcium channel, CaV1.2. While Varanus varius venom did not have discernable effects in the avian tissue preparation assay at the concentration tested, in the biointerferometry assay both V. varius and V. salvadorii bound to voltage-sensing domain IV of both NaV1.4 and CaV1.2, similar to H. suspectum venom. The ability of varanid venoms to bind to mammalian ion channels but not to the avian tissue preparation suggests prey-selective actions, as did the differential potency within the Heloderma venoms for avian versus mammalian pathophysiological targets. This study thus presents the detailed characterization of Heloderma venom ion channel neurotoxicity and offers the first evidence of varanid lizard venom neurotoxicity. In addition, the data not only provide information useful to understanding the clinical effects produced by envenomations, but also reveal their utility as physiological probes, and underscore the potential utility of neglected venomous lineages in the drug design and development pipeline.
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Affiliation(s)
- James S. Dobson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Richard J. Harris
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Christina N. Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Tam Huynh
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (T.H.); (W.C.H.)
| | - Wayne C. Hodgson
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (T.H.); (W.C.H.)
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Rudy Fourmy
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-Bois, Belgium; (R.F.); (A.V.)
| | - Aude Violette
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-Bois, Belgium; (R.F.); (A.V.)
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
- Correspondence: ; Tel.: +61-7-336-58515
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5
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Abstract
Context: Heloderma bites are rare and generally mild, but a few cases can be life threatening. Methods: Description of Heloderma bite was searched in medical literature. Discussion: We present a synthesis of clinical and biomedical effects of envenomation by Heloderma sp. based on 22 well identified cases described in medical literature. Three life-threatening syndromes, concomitant or not, may be involved: (a) angioedema which can lead to respiratory tract obstruction, (b) significant fluid losses due to diarrhea, vomiting and sweating, associated with hypokalemia and sometimes metabolic acidosis, and (c) atrioventricular conduction disorders simulating cardiac ischemia. Conclusion: Heloderma bite are quite rare and generally mild. However, few severe cases may require emergency resuscitation. There is no antivenom, and the treatment is only symptomatic and supportive.
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Affiliation(s)
- Jean-Philippe Chippaux
- CRT, Institut Pasteur, Paris, France.,MERIT, IRD, Université Paris 5, Sorbonne Paris Cité, Paris, France
| | - Karim Amri
- Snakebite institute of Latin America, Belize, USA
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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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Möller C, Davis WC, Clark E, DeCaprio A, Marí F. Conodipine-P1-3, the First Phospholipases A 2 Characterized from Injected Cone Snail Venom. Mol Cell Proteomics 2019; 18:876-891. [PMID: 30765458 DOI: 10.1074/mcp.ra118.000972] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/06/2019] [Indexed: 12/30/2022] Open
Abstract
The phospholipase A2 (PLA2s) superfamily are ubiquitous small enzymes that catalyze the hydrolysis of phospholipids at the sn-2 ester bond. PLA2s in the venom of cone snails (conodipines, Cdpi) are composed of two chains termed as alpha and beta subunits. Conodipines are categorized within the group IX of PLA2s. Here we describe the purification and biochemical characterization of three conodipines (Cdpi-P1, -P2 and -P3) isolated from the injected venom of Conus purpurascens Using proteomics methods, we determined the full sequences of all three conodipines. Conodipine-P1-3 have conserved consensus catalytic domain residues, including the Asp/His dyad. Additionally, these enzymes are expressed as a mixture of proline hydroxylated isoforms. The activities of the native Conodipine-Ps were evaluated by conventional colorimetric and by MS-based methods, which provide the first detailed cone snail venom conodipine activity monitored by mass spectrometry. Conodipines can have medicinal applications such inhibition of cancer proliferation, bacterial and viral infections among others.
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Affiliation(s)
- Carolina Möller
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412
| | - W Clay Davis
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412
| | - Evan Clark
- §Department of Biomedical Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
| | - Anthony DeCaprio
- ¶Department of Chemistry and Biochemistry, Florida International University, SW 8th St, Miami, Florida, 33119
| | - Frank Marí
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412;.
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Wang Y, Sherchan P, Huang L, Akyol O, McBride DW, Zhang JH. Multiple mechanisms underlying neuroprotection by secretory phospholipase A2 preconditioning in a surgically induced brain injury rat model. Exp Neurol 2018; 300:30-40. [PMID: 29074417 PMCID: PMC5745263 DOI: 10.1016/j.expneurol.2017.10.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/12/2017] [Accepted: 10/21/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Intra-operative bleeding, post-operative brain edema and neuroinflammation are major complications in patients with surgical brain injury (SBI). Phospholipase A2 (PLA2) is the upstream enzyme which initiates the PLA2, 5-lipoxygenase (5-LOX) and leukotriene B4 (LTB4) inflammatory pathway. We hypothesized PLA2preconditioning (PPC) prior to SBI can activate endogenous anti-inflammatory responses to protect against SBI. This study evaluated if PPC can ameliorate neurosurgical complications and elucidated PPC-mediated possible protective mechanisms in a rat SBI model. METHODS Total 105 adult male Sprague Dawley rats were used for this study. SBI was induced by partial resection of the right frontal lobe. PLA2 or 0.9% NaCl was injected via rats' tail vein for 3 consecutive days prior to SBI. For mechanism study, a selective PLA2 inhibitor, Manoalide and 5-LOX inhibitor, Zileuton were injected intravenously with PPC to elucidate the role of PLA2 and 5-LOX in PPC-mediated anti-inflammatory effects. Brain water content (BWC) and lung water content, neurological tests, ELISA, western blot, immunohistochemistry, white blood cells (WBC) count, and spectrophotometric assay for intra-operative hemorrhage volume were evaluated. RESULTS First, PPC reduced brain water content, intra-operative bleeding, and improved neurological function after SBI. Second, PPC decreased 5-LOX expression and brain leukocyte infiltration, while increasing glial fibrillary acidic protein (GFAP) expression in the peri-resection brain tissue after SBI. Third, PPC induced peripheral inflammation represented by mild pulmonary inflammation and increased peripheral blood WBC count and LTB4 level. Lastly, PPC increased blood glucose concentration and glucocorticoid levels after SBI. In addition, PPC mediated above-mentioned changes were partially reversed by administration of PLA2 inhibitor, Manoalide and 5-LOX inhibitor, Zileuton. CONCLUSIONS PPC conferred neuroprotection against SBI via multi-target involvement induced anti-inflammatory mechanisms.
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Affiliation(s)
- Yuechun Wang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
- Department of Physiology, Jinan University School of Medicine, Guangzhou, Guangdong Province, China
| | - Prativa Sherchan
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
| | - Lei Huang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
- Department of Anesthesiology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
| | - Onat Akyol
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
| | - Devin W. McBride
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
| | - John H. Zhang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
- Department of Anesthesiology, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
- Department of Neurosurgery, Loma Linda University School of Medicine, Loma Linda, California, 92354, USA
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Koludarov I, Jackson TN, Brouw BOD, Dobson J, Dashevsky D, Arbuckle K, Clemente CJ, Stockdale EJ, Cochran C, Debono J, Stephens C, Panagides N, Li B, Manchadi MLR, Violette A, Fourmy R, Hendrikx I, Nouwens A, Clements J, Martelli P, Kwok HF, Fry BG. Enter the Dragon: The Dynamic and Multifunctional Evolution of Anguimorpha Lizard Venoms. Toxins (Basel) 2017; 9:E242. [PMID: 28783084 PMCID: PMC5577576 DOI: 10.3390/toxins9080242] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/04/2017] [Accepted: 08/04/2017] [Indexed: 01/08/2023] Open
Abstract
While snake venoms have been the subject of intense study, comparatively little work has been done on lizard venoms. In this study, we have examined the structural and functional diversification of anguimorph lizard venoms and associated toxins, and related these results to dentition and predatory ecology. Venom composition was shown to be highly variable across the 20 species of Heloderma, Lanthanotus, and Varanus included in our study. While kallikrein enzymes were ubiquitous, they were also a particularly multifunctional toxin type, with differential activities on enzyme substrates and also ability to degrade alpha or beta chains of fibrinogen that reflects structural variability. Examination of other toxin types also revealed similar variability in their presence and activity levels. The high level of venom chemistry variation in varanid lizards compared to that of helodermatid lizards suggests that venom may be subject to different selection pressures in these two families. These results not only contribute to our understanding of venom evolution but also reveal anguimorph lizard venoms to be rich sources of novel bioactive molecules with potential as drug design and development lead compounds.
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Affiliation(s)
- Ivan Koludarov
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
| | - Timothy Nw Jackson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
- Australian Venom Research Unit, School of Biomedical Sciences, Level 2 Medical Building, University of Melbourne, Victoria 3010, Australia.
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
| | - James Dobson
- 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.
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK.
| | - Christofer J Clemente
- University of the Sunshine Coast, School of Science and Engineering, Sippy Downs, Queensland 4558, Australia.
| | | | - Chip Cochran
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
| | - Carson Stephens
- School of Biomedical Sciences, Queensland University of Technology, Brisbane QLD 4001, Australia.
| | - Nadya Panagides
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
| | - Bin Li
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau.
| | | | - Aude Violette
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-bois, Belgium.
| | - Rudy Fourmy
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-bois, Belgium.
| | - Iwan Hendrikx
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia QLD 4072, Australia.
| | - Amanda Nouwens
- School of Chemistry and Molecular Biology, University of Queenslnd, St. Lucia QLD 4072, Australia.
| | - Judith Clements
- School of Biomedical Sciences, Queensland University of Technology, Brisbane QLD 4001, Australia.
| | | | - Hang Fai Kwok
- 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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10
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Dias RG, Sampaio SC, Sant'Anna MB, Cunha FQ, Gutiérrez JM, Lomonte B, Cury Y, Picolo G. Articular inflammation induced by an enzymatically-inactive Lys49 phospholipase A 2: activation of endogenous phospholipases contributes to the pronociceptive effect. J Venom Anim Toxins Incl Trop Dis 2017; 23:18. [PMID: 28344594 PMCID: PMC5364601 DOI: 10.1186/s40409-017-0104-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 02/24/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Arthritis is a set of inflammatory conditions that induce aching, stiffness, swelling, pain and may cause functional disability with severe consequences to the patient's lives. These are multi-mediated pathologies that cannot be effectively protected and/or treated. Therefore, the aim of this study was to establish a new model of acute arthritis, using a Lys49-PLA2 (Bothrops asper myotoxin II; MT-II) to induce articular inflammation. METHODS The articular inflammation was induced by MT-II (10 μg/joint) injection into the left tibio-tarsal or femoral-tibial-patellar joints. Cellular influx was evaluated counting total and differential cells that migrated to the joint. The plasma extravasation was determined using Evans blue dye. The edematogenic response was evaluated measuring the joint thickness using a caliper. The articular hypernociception was determined by a dorsal flexion of the tibio-tarsal joint using an electronic pressure-meter test. The mediators involved in the articular hypernociception were evaluated using receptor antagonists and enzymatic inhibitors. RESULTS Plasma extravasation in the knee joints was observed 5 and 15 min after MT-II (10 μg/joint) injection. MT-II also induced a polymorphonuclear cell influx into the femoral-tibial-patellar joints observed 8 h after its injection, a period that coincided with the peak of the hyperalgesic effect. Hyperalgesia was inhibited by the pretreatment of the animals with cyclooxygenase inhibitor indomethacin, with type-2 cyclooxygenase inhibitor celecoxib, with AACOCF3 and PACOCF3, inhibitors of cytosolic and Ca2+-independent PLA2s, respectively, with bradykinin B2 receptor antagonist HOE 140, with antibodies against TNFα, IL-1β, IL-6 and CINC-1 and with selective ET-A (BQ-123) and ET-B (BQ-788) endothelin receptors antagonists. The MT-II-induced hyperalgesia was not altered by the lipoxygenase inhibitor zileuton, by the bradykinin B1 receptor antagonist Lys-(Des-Arg9,Leu8)-bradykinin, by the histamine and serotonin antagonists promethazine and methysergide, respectively, by the nitric oxide inhibitor LNMMA and by the inhibitor of matrix 1-, 2-, 3-, 8- and 9- metalloproteinases GM6001 (Ilomastat). CONCLUSION These results demonstrated the multi-mediated characteristic of the articular inflammation induced by MT-II, which demonstrates its relevance as a model for arthritis mechanisms and treatment evaluation.
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Affiliation(s)
- Renata Gonçalves Dias
- Special Laboratory of Pain and Signaling, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, SP CEP 05503-900 Brazil.,Healthy Sciences Institute, Paulista University (UNIP), São Paulo, SP Brazil
| | - Sandra Coccuzzo Sampaio
- Laboratory of Pathophysiology, Butantan Institute, São Paulo, SP Brazil.,Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
| | - Morena Brazil Sant'Anna
- Special Laboratory of Pain and Signaling, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, SP CEP 05503-900 Brazil
| | - Fernando Queiroz Cunha
- Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - José María Gutiérrez
- Clodomiro Picado Institute, Faculty of Microbiology, University of Costa Rica, San José, Costa Rica
| | - Bruno Lomonte
- Clodomiro Picado Institute, Faculty of Microbiology, University of Costa Rica, San José, Costa Rica
| | - Yara Cury
- Special Laboratory of Pain and Signaling, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, SP CEP 05503-900 Brazil
| | - Gisele Picolo
- Special Laboratory of Pain and Signaling, Butantan Institute, Av. Vital Brazil, 1500, São Paulo, SP CEP 05503-900 Brazil
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11
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Sanggaard KW, Dyrlund TF, Thomsen LR, Nielsen TA, Brøndum L, Wang T, Thøgersen IB, Enghild JJ. Characterization of the gila monster (Heloderma suspectum suspectum) venom proteome. J Proteomics 2015; 117:1-11. [DOI: 10.1016/j.jprot.2015.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/06/2015] [Accepted: 01/10/2015] [Indexed: 12/23/2022]
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12
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Koludarov I, Sunagar K, Undheim EAB, Jackson TNW, Ruder T, Whitehead D, Saucedo AC, Mora GR, Alagon AC, King G, Antunes A, Fry BG. Structural and Molecular Diversification of the Anguimorpha Lizard Mandibular Venom Gland System in the Arboreal Species Abronia graminea. J Mol Evol 2012; 75:168-83. [DOI: 10.1007/s00239-012-9529-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/29/2012] [Indexed: 11/24/2022]
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13
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Wong ES, Belov K. Venom evolution through gene duplications. Gene 2012; 496:1-7. [DOI: 10.1016/j.gene.2012.01.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 01/10/2012] [Accepted: 01/10/2012] [Indexed: 12/30/2022]
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14
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Fry BG, Winter K, Norman JA, Roelants K, Nabuurs RJA, van Osch MJP, Teeuwisse WM, van der Weerd L, McNaughtan JE, Kwok HF, Scheib H, Greisman L, Kochva E, Miller LJ, Gao F, Karas J, Scanlon D, Lin F, Kuruppu S, Shaw C, Wong L, Hodgson WC. Functional and structural diversification of the Anguimorpha lizard venom system. Mol Cell Proteomics 2010; 9:2369-90. [PMID: 20631207 DOI: 10.1074/mcp.m110.001370] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Venom has only been recently discovered to be a basal trait of the Anguimorpha lizards. Consequently, very little is known about the timings of toxin recruitment events, venom protein molecular evolution, or even the relative physical diversifications of the venom system itself. A multidisciplinary approach was used to examine the evolution across the full taxonomical range of this ∼130 million-year-old clade. Analysis of cDNA libraries revealed complex venom transcriptomes. Most notably, three new cardioactive peptide toxin types were discovered (celestoxin, cholecystokinin, and YY peptides). The latter two represent additional examples of convergent use of genes in toxic arsenals, both having previously been documented as components of frog skin defensive chemical secretions. Two other novel venom gland-overexpressed modified versions of other protein frameworks were also recovered from the libraries (epididymal secretory protein and ribonuclease). Lectin, hyaluronidase, and veficolin toxin types were sequenced for the first time from lizard venoms and shown to be homologous to the snake venom forms. In contrast, phylogenetic analyses demonstrated that the lizard natriuretic peptide toxins were recruited independently of the form in snake venoms. The de novo evolution of helokinestatin peptide toxin encoding domains within the lizard venom natriuretic gene was revealed to be exclusive to the helodermatid/anguid subclade. New isoforms were sequenced for cysteine-rich secretory protein, kallikrein, and phospholipase A(2) toxins. Venom gland morphological analysis revealed extensive evolutionary tinkering. Anguid glands are characterized by thin capsules and mixed glands, serous at the bottom of the lobule and mucous toward the apex. Twice, independently this arrangement was segregated into specialized serous protein-secreting glands with thick capsules with the mucous lobules now distinct (Heloderma and the Lanthanotus/Varanus clade). The results obtained highlight the importance of utilizing evolution-based search strategies for biodiscovery and emphasize the largely untapped drug design and development potential of lizard venoms.
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Affiliation(s)
- Bryan G Fry
- Venomics Research Laboratory, Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia.
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15
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Lopez-Johnston JC, de Bosch N, Scannone H, Rodríguez-Acosta A. Inhibition of adrenaline and adenosine diphosphate induced platelet aggregation by Lansberg's hognose pit viper (Porthidium lansbergii hutmanni) venom. Ann Hematol 2007; 86:879-85. [PMID: 17891398 DOI: 10.1007/s00277-007-0354-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 07/18/2007] [Indexed: 11/29/2022]
Abstract
The haemostatic components of venom from the genus Porthidium has been poorly studied, although it is known that severe manifestations occur when humans are envenomed, which include invasive oedema and disseminated ecchymosis. The effects of venom on blood platelets are commonly studied and are normally carried out with platelet-rich plasma (PRP). A series of crude venom dilutions was used to determine the effects of adenosine diphosphate (2 microM) and adrenaline (11 microM) induced platelet aggregation. Venom of Porthidium lansbergii hutmanni was fractioned by anionic exchange chromatography, and the fractions were also used to determine the 50% inhibition of adenosine diphosphate (ADP) and adrenaline-induced platelet aggregating dose (AD50). Crude venom has more effect in inhibiting adrenaline-induced aggregation (AD50 = 0.0043 microg) followed by the adenosine diphosphate (AD50 = 17 microg). Peaks I and II obtained by chromatography also inhibited adrenaline-induced platelet aggregation with an AD50 of 3.2 and 0.013 microg, respectively, and both peaks inhibited ADP-induced platelet aggregation with an AD50 of 10 microg. The main purpose of this work was to characterise the in vitro effects caused by P. lansbergii hutmanni crude venom and its fractions on the platelet aggregation mediated by adrenaline and ADP agonists.
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Affiliation(s)
- J C Lopez-Johnston
- Laboratorio de Investigaciones, Facultad de Farmacia, Universidad Central de Venezuela, Caracas, Venezuela
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16
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López-Johnston JC, de Bosch N, Scannone H, Rodríguez-Acosta A. Inhibition of collagen, and thrombin-induced platelet aggregation by Lansberg’s hognose pit viper (Porthidium lansbergii hutmanni) venom. J Thromb Thrombolysis 2007; 24:275-82. [PMID: 17486300 DOI: 10.1007/s11239-007-0040-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
The Porthidium genus is represented by the P. lansbergii rozei and P. lansbergii hutmanni (Plh) subspecies in Venezuela. The venom components of these have been little studied, probably due to the low incidence of reported accidents, although acute and serious local effects such as invasive edema and disseminated ecchymosis are present during human envenonation. The aim of this work was to characterize the in vitro effects of crude P. l. hutmanni venom, and its fractions, on platelet aggregation triggered by two physiologic agonists: thrombin and collagen. The effects of thrombin and collagen were observed on a platelet-rich plasma (PRP) solution (3 x 10(5) platelets/microL) using serial dilutions of P. l. hutmanni venom (0.625-40 microg). The crude venom was fractionated by anionic exchange chromatography and two peaks obtained. Crude venom and both fractions were highly inhibitory on platelet aggregation mediated by the two agonists. The anti-aggregating dose (AD(50)) for both agonists was determined. PRP collagen-triggered aggregation was most inhibited by the crude venom (AD(50) = 0.67 microg) when compared with PRP thrombin-triggered aggregation (AD(50) = 4.92 microg). Collagen-induced aggregation was more intensely inhibited by venom than thrombin-induced aggregation. In conclusion, to specify the inhibition mechanisms involved for each of the active components in the venom from these subspecies, we must characterize and purify the inhibitors of aggregation from P. l. hutmanni venom, with the purpose of suggesting new pharmacological substances to be incorporated into the therapeutic arsenal to treat hemostatic pathologies related to high levels of platelet aggregation.
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Affiliation(s)
- Juan C López-Johnston
- Laboratorio de Investigaciones, Facultad de Farmacia, Universidad Central de Venezuela, Caracas, Venezuela
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17
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de Albuquerque Modesto JC, Spencer PJ, Fritzen M, Valença RC, Oliva MLV, da Silva MB, Chudzinski-Tavassi AM, Guarnieri MC. BE-I-PLA2, a novel acidic phospholipase A2 from Bothrops erythromelas venom: isolation, cloning and characterization as potent anti-platelet and inductor of prostaglandin I2 release by endothelial cells. Biochem Pharmacol 2006; 72:377-84. [PMID: 16750518 DOI: 10.1016/j.bcp.2006.04.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 04/28/2006] [Accepted: 04/28/2006] [Indexed: 10/24/2022]
Abstract
A novel acidic Asp49 phospholipase A(2) was isolated from Bothrops erythromelas (jararaca malha-de-cascavel) snake venom by four chromatographic steps. BE-I-PLA2 present a molecular weight of 13,649.57 Da as estimated by mass spectrometry. N-terminal and four internal peptides were sequenced, covering around one-third of the complete toxin sequence. The complete BE-I-PLA2 cDNA was cloned from a B. erythromelas venom-gland cDNA library. The cDNA sequence possesses 457 bp and encodes a protein with significant sequence similarity to many other phospholipase A(2) from snake venoms. When tested in platelet rich plasma, the enzyme showed a potent inhibitory effect on aggregation induced by arachidonic acid and collagen, but not ADP. On the other hand, BE-I-PLA2 did not modify aggregation in washed platelet. Furthermore, no action of BE-I-PLA2 on the principal platelets receptors was observed. Chemical modification with p-bromophenacyl bromide abolished the enzymatic activity of BE-I-PLA2, but its anti-platelet activity was only partially inhibited. In human umbilical-cord veins endothelial cells, BE-I-PLA2 was neither apoptotic nor proliferative but stimulated endothelial cells to release prostaglandin I(2), suggesting an increase of its potential anti-platelet activity in vivo. Further studies are required in order to determine the exact mechanism of action of BE-I-PLA2 in the inhibition of platelet aggregation.
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18
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Fry BG, Vidal N, Norman JA, Vonk FJ, Scheib H, Ramjan SFR, Kuruppu S, Fung K, Hedges SB, Richardson MK, Hodgson WC, Ignjatovic V, Summerhayes R, Kochva E. Early evolution of the venom system in lizards and snakes. Nature 2005; 439:584-8. [PMID: 16292255 DOI: 10.1038/nature04328] [Citation(s) in RCA: 374] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 10/17/2005] [Indexed: 11/09/2022]
Abstract
Among extant reptiles only two lineages are known to have evolved venom delivery systems, the advanced snakes and helodermatid lizards (Gila Monster and Beaded Lizard). Evolution of the venom system is thought to underlie the impressive radiation of the advanced snakes (2,500 of 3,000 snake species). In contrast, the lizard venom system is thought to be restricted to just two species and to have evolved independently from the snake venom system. Here we report the presence of venom toxins in two additional lizard lineages (Monitor Lizards and Iguania) and show that all lineages possessing toxin-secreting oral glands form a clade, demonstrating a single early origin of the venom system in lizards and snakes. Construction of gland complementary-DNA libraries and phylogenetic analysis of transcripts revealed that nine toxin types are shared between lizards and snakes. Toxinological analyses of venom components from the Lace Monitor Varanus varius showed potent effects on blood pressure and clotting ability, bioactivities associated with a rapid loss of consciousness and extensive bleeding in prey. The iguanian lizard Pogona barbata retains characteristics of the ancestral venom system, namely serial, lobular non-compound venom-secreting glands on both the upper and lower jaws, whereas the advanced snakes and anguimorph lizards (including Monitor Lizards, Gila Monster and Beaded Lizard) have more derived venom systems characterized by the loss of the mandibular (lower) or maxillary (upper) glands. Demonstration that the snakes, iguanians and anguimorphs form a single clade provides overwhelming support for a single, early origin of the venom system in lizards and snakes. These results provide new insights into the evolution of the venom system in squamate reptiles and open new avenues for biomedical research and drug design using hitherto unexplored venom proteins.
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Affiliation(s)
- Bryan G Fry
- Australian Venom Research Unit, Level 8, School of Medicine, University of Melbourne, Parkville, Victoria 3010, Australia.
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19
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Sundell IB, Rånby M, Zuzel M, Robinson KA, Theakston RDG. In vitro procoagulant and anticoagulant properties of Naja naja naja venom. Toxicon 2003; 42:239-47. [PMID: 14559074 DOI: 10.1016/s0041-0101(03)00137-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bites by the Indian cobra (Naja naja naja) are common in India and Sri Lanka because of its close association with humans. Cobra venoms are complex and contain several toxic components, including neurotoxins that cause post-synaptic neuromuscular blockade with respiratory paralysis and even death. Bites may also cause extensive local necrosis by mechanisms not fully elucidated. Although no significant coagulopathy has been reported, N.n. naja venom can form blood clots in vitro by activating prothrombin as demonstrated by thrombin-specific chromogenic substrate. Scanning electron microscopy demonstrates that the clots formed by venom lack the thin fibrin strands of normal blood clots formed by thromboplastin or glass contact. Rheometry shows that clots formed by venom have abnormally low elasticity over an extended period and then, as the platelets contract, a retarded and more feeble increase in elasticity. Purified N.n. naja venom PLA2 inhibits platelet aggregation in PRP and explains the decreased clot retraction and retarded and compromised elasticity build up. The present study shows that the PLA2 and the prothrombin activator from N.n. naja venom have effects on haemostasis and blood clotting, although such effects are not observed systemically in envenomed humans.
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Affiliation(s)
- I B Sundell
- Department of Haematology, University of Liverpool, Liverpool L69 3GA, UK.
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20
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Huang MZ, Gopalakrishnakone P, Kini RM. Role of enzymatic activity in the antiplatelet effects of a phospholipase A2 from Ophiophagus hannah snake venom. Life Sci 1997; 61:2211-7. [PMID: 9393940 DOI: 10.1016/s0024-3205(97)00923-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A phospholipase A2 (OHV A-PLA2) from the venom of Ophiophagus hannah (King cobra) is an acidic protein exhibiting antiplatelet activity. In in vitro tests, OHV APLA2 showed a marked inhibitory effect on platelet aggregation induced by ADP, collagen and arachidonic acid in both human whole blood and platelet-rich plasma in a dose-dependent manner. The antiplatelet effects of OHV A-PLA2 did not increase when preincubation times of platelets and OHV A-PLA2 were prolonged indicating phospholipid hydrolysis did not significantly contribute to the antiplatelet effects. Alkylation of active site His residue using p-bromophenacyl bromide resulted in the complete loss of enzymatic activity, but the modified enzyme retained more than 30% of its antiplatelet effects. These results indicate that the antiplatelet effects of OHV A-PLA2 appear to be independent of its enzymatic activity, and there are separate sites responsible for the catalytic and antiplatelet activities.
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Affiliation(s)
- M Z Huang
- Department of Anatomy, National University of Singapore, Singapore
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21
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Abstract
Phospholipase A2 (PLA2), an enzyme found in most snake venoms, catalyzes the hydrolysis of phospholipids in biological membranes, and some have presynaptic neurotoxic activity. A synthetic substrate, 4-nitro-3-(octanoyloxy)benzoic acid, was synthesized and purified on a silica gel column using a published method. This substrate was used to develop an endpoint assay which is rapid and requires a minimum of equipment. This aqueous assay system allowed enzyme activity to be examined without the use of radioactive substrates or organic solvents, minimizing waste disposal concerns. Whole venoms, partially purified enzyme isolated from Crotalus mitchelli pyrrhus venom, tissue extracts and commercial preparations were employed as sources of PLA2. Results show that this method is a convenient and specific assay for PLA2 from several sources and is particularly suited for assaying large numbers of fractions generated during purification procedures.
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Affiliation(s)
- M Holzer
- Department of Biological Sciences, University of Northern Colorado, Greeley 80639, USA
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Affiliation(s)
- J P Raufman
- Department of Medicine, State University of New York-Health Science Center at Brooklyn, NY 11203-2098, USA
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Laing GD, Kamiguti AS, Wilkinson MC, Lowe GM, Theakston RD. Characterisation of a purified phospholipase A2 from the venom of the Papuan black snake (Pseudechis papuanus). BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1250:137-43. [PMID: 7632717 DOI: 10.1016/0167-4838(95)00081-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A neutral phospholipase A2 (PLA2) was separated from Pseudechis papuanus venom by a two-stage FPLC procedure of cation exhange and phenyl-Superose chromatography. It had a molecular mass of 15 kDa and a lower LD50 value than a co-separated haemorrhagic fraction, indicating a higher lethal potency. In vitro tests confirmed the powerful inhibition of platelet aggregation by the PLA2 and strong anticoagulant activity initially observed with whole venom. Ultrastructural studies showed that platelets lost their discoid shape and developed membranous projections with a general decrease in electron-density of the cytosol and disruption of the microfilaments following incubation with the enzyme. Amino acid sequence analysis of the N-terminus and some internal peptides demonstrated a high degree of homology with PLA2s from other Pseudechis venoms. Our results indicate that this fraction is the main agent responsible for the haemostatic disorders in envenomed patients.
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Affiliation(s)
- G D Laing
- Snake Venom Research Unit, Liverpool School of Tropical Medicine, UK
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