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Camarano Eula MA, Bayona-Serrano JD, Nishiyama-Jr MY, Squaiella-Baptistão CC, Santoro ML, Junqueira-de-Azevedo IDLM. The underestimated local effects of Micrurus corallinus venom revealed by gene expression and histopathological alterations. Toxicon 2025; 259:108368. [PMID: 40268250 DOI: 10.1016/j.toxicon.2025.108368] [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: 02/13/2025] [Revised: 04/15/2025] [Accepted: 04/16/2025] [Indexed: 04/25/2025]
Abstract
The mechanisms of action of elapid neurotoxins have been widely studied; however, the pathophysiological effects of these venoms, particularly from coral snakes, have not been extensively investigated. To gain a deeper understanding of the mechanisms involved in the local and systemic toxicity of Micrurus corallinus venom and their genomic responses, we injected mice with 2.70 μg of venom, corresponding to a sub-lethal dose (50 % of the LD50), and evaluated the effects using transcriptomic and histopathological approaches. mRNA was extracted from the liver, spleen, kidney, heart, brain, diaphragm, and both right and left gastrocnemius muscles of control and treated animals and subjected to RNA sequencing (RNA-Seq) to perform functional analyses of differentially expressed genes (DEGs). In the right gastrocnemius, the site of venom injection, we observed significant histopathological changes characterized by a pronounced local inflammatory response. Consistent with these findings, enrichment analyses revealed 2454 DEGs in the right gastrocnemius, mostly involved in inflammatory pathways. Systemically, the liver emerged as the most affected non-local organ, showing over 400 DEGs containing several up-regulated genes involved in the production of acute phase proteins. These results underscore that inflammation possibly induced by the sub-lethal amounts of venom typically injected during human envenomation, and not only the neurotoxicity, could be a potentially deleterious effect of venom and should not be ruled out when diagnosing envenomation caused by coral snakes.
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Biruš I, Šeba T, Marić M, Gabričević M, Weitner T. Design and Binding Affinity of Antisense Peptides for Snake Venom Neutralization. Molecules 2025; 30:903. [PMID: 40005213 PMCID: PMC11858715 DOI: 10.3390/molecules30040903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2024] [Revised: 02/04/2025] [Accepted: 02/12/2025] [Indexed: 02/27/2025] Open
Abstract
Snakebites are a significant public health problem in many tropical and subtropical regions, causing extensive morbidity and mortality. Traditional snake antivenoms face multiple challenges, including allergenicity, high production costs, and logistical difficulties, highlighting the urgent need for new therapeutic approaches. This pilot study explores the potential of oligopeptides as therapeutic inhibitors targeting the neurotoxic sites of ammodytoxin A (AtxA; PDB: 3G8G) from Vipera ammodytes. We selected two sense oligopeptides to represent critical neurotoxic regions of AtxA as targets for inhibition by complementary antisense peptides. Utilizing a heuristic antisense peptide design based on the molecular recognition theory, we modeled two antisense oligopeptides as complementary counterparts for each sense oligopeptide. The modeled sense and antisense peptides were commercially synthesized, and their binding affinities were evaluated using spectrofluorometric titrations. The determined dissociation constants (KD) were in the range of 1-10 μM for all sense-antisense pairs, revealing relatively strong binding affinities. Confirmation of sense-antisense peptide binding prompted further investigation into their potential binding to the native target protein through global docking simulations using the HPEPDOCK web server. The results highlight the applicability of molecular recognition theory in the development of antisense peptides that could change therapeutic strategies in various biomedical fields. Further studies are needed to investigate the therapeutic efficacy and broader applications of these peptides.
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Affiliation(s)
| | | | | | | | - Tin Weitner
- Department of General and Inorganic Chemistry, University of Zagreb Faculty of Pharmacy and Biochemistry, A. Kovačića 1, 10000 Zagreb, Croatia
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Ding SM, Yap MKK. Deciphering toxico-proteomics of Asiatic medically significant venomous snake species: A systematic review and interactive data dashboard. Toxicon 2024; 250:108120. [PMID: 39393539 DOI: 10.1016/j.toxicon.2024.108120] [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: 08/07/2024] [Revised: 09/30/2024] [Accepted: 10/06/2024] [Indexed: 10/13/2024]
Abstract
Snakebite envenomation (SBE) is a neglected tropical disease (NTD) with an approximate 1.8 million cases annually. The tremendous figure is concerning, and the currently available treatment for snakebite envenomation is antivenom. However, the current antivenom has limited cross-neutralisation activity due to the variations in snake venom composition across species and geographical locations. The proteomics of medically important venomous species is essential as they study the venom compositions within and among different species. The advancement of sophisticated proteomic approaches allows intensive investigation of snake venoms. Nevertheless, there is a need to consolidate the venom proteomics profiles and distribution analysis to examine their variability patterns. This review systematically analysed the proteomics and toxicity profiles of medically important venomous species from Asia across different geographical locations. An interactive dashboard - Asiatic Proteomics Interactive Datasets was curated to consolidate the distribution patterns of the venom compositions, serve as a comprehensive directory for large-scale comparative meta-analyses. The population proteomics demonstrate higher diversities in the predominant venom toxins. Besides, inter-regional differences were also observed in Bungarus sp., Naja sp., Calliophis sp., and Ophiophagus hannah venoms. The elapid venoms are predominated with three-finger toxins (3FTXs) and phospholipase A2 (PLA2). Intra-regional variation is only significantly observed in Naja naja venoms. Proteomics diversity is more prominent in viper venoms, with widespread dominance observed in snake venom metalloproteinase (SVMP) and snake venom serine protease (SVSP). Correlations exist between the proteomics profiles and the toxicity (LD50) of the medically important venomous species. Additionally, the predominant toxins, alongside their pathophysiological effects, were highlighted and discussed as well. The insights of interactive toxico-proteomics datasets provide comprehensive frameworks of venom dynamics and contribute to developing antivenoms for snakebite envenomation. This could reduce misdiagnosis of SBE and accelerate the researchers' data mining process.
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Affiliation(s)
- Sher Min Ding
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia
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4
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Sampat GH, Hiremath K, Dodakallanavar J, Patil VS, Harish DR, Biradar P, Mahadevamurthy RK, Barvaliya M, Roy S. Unraveling snake venom phospholipase A 2: an overview of its structure, pharmacology, and inhibitors. Pharmacol Rep 2023; 75:1454-1473. [PMID: 37926795 DOI: 10.1007/s43440-023-00543-8] [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: 06/12/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 11/07/2023]
Abstract
Snake bite is a neglected disease that affects millions of people worldwide. WHO reported approximately 5 million people are bitten by various species of snakes each year, resulting in nearly 1 million deaths and an additional three times cases of permanent disability. Snakes utilize the venom mainly for immobilization and digestion of their prey. Snake venom is a composition of proteins and enzymes which is responsible for its diverse pharmacological action. Snake venom phospholipase A2 (SvPLA2) is an enzyme that is present in every snake species in different quantities and is known to produce remarkable functional diversity and pharmacological action like inflammation, necrosis, myonecrosis, hemorrhage, etc. Arachidonic acid, a precursor to eicosanoids, such as prostaglandins and leukotrienes, is released when SvPLA2 catalyzes the hydrolysis of the sn-2 positions of membrane glycerophospholipids, which is responsible for its actions. Polyvalent antivenom produced from horses or lambs is the standard treatment for snake envenomation, although it has many drawbacks. Traditional medical practitioners treat snake bites using plants and other remedies as a sustainable alternative. More than 500 plant species from more than 100 families reported having venom-neutralizing abilities. Plant-derived secondary metabolites have the ability to reduce the venom's adverse consequences. Numerous studies have documented the ability of plant chemicals to inhibit the enzymes found in snake venom. Research in recent years has shown that various small molecules, such as varespladib and methyl varespladib, effectively inhibit the PLA2 toxin. In the present article, we have overviewed the knowledge of snake venom phospholipase A2, its classification, and the mechanism involved in the pathophysiology of cytotoxicity, myonecrosis, anticoagulation, and inflammation clinical application and inhibitors of SvPLA2, along with the list of studies carried out to evaluate the potency of small molecules like varespladib and secondary metabolites from the traditional medicine for their anti-PLA2 effect.
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Affiliation(s)
- Ganesh H Sampat
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
- KLE College of Pharmacy, Belagavi, KLE Academy of Higher Education and Research, Belagavi, Karnataka, 590010, India
| | - Kashinath Hiremath
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
- KLE College of Pharmacy, Belagavi, KLE Academy of Higher Education and Research, Belagavi, Karnataka, 590010, India
| | - Jagadeesh Dodakallanavar
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
- KLE College of Pharmacy, Belagavi, KLE Academy of Higher Education and Research, Belagavi, Karnataka, 590010, India
| | - Vishal S Patil
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
- KLE College of Pharmacy, Belagavi, KLE Academy of Higher Education and Research, Belagavi, Karnataka, 590010, India
| | - Darasaguppe R Harish
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India.
| | - Prakash Biradar
- KLE College of Pharmacy, Belagavi, KLE Academy of Higher Education and Research, Belagavi, Karnataka, 590010, India.
| | | | - Manish Barvaliya
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
| | - Subarna Roy
- ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka, 590010, India
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Osipov A, Utkin Y. What Are the Neurotoxins in Hemotoxic Snake Venoms? Int J Mol Sci 2023; 24:ijms24032919. [PMID: 36769242 PMCID: PMC9917609 DOI: 10.3390/ijms24032919] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/10/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Snake venoms as tools for hunting are primarily aimed at the most vital systems of the prey, especially the nervous and circulatory systems. In general, snakes of the Elapidae family produce neurotoxic venoms comprising of toxins targeting the nervous system, while snakes of the Viperidae family and most rear-fanged snakes produce hemotoxic venoms directed mainly on blood coagulation. However, it is not all so clear. Some bites by viperids results in neurotoxic signs and it is now known that hemotoxic venoms do contain neurotoxic components. For example, viperid phospholipases A2 may manifest pre- or/and postsynaptic activity and be involved in pain and analgesia. There are other neurotoxins belonging to diverse families ranging from large multi-subunit proteins (e.g., C-type lectin-like proteins) to short peptide neurotoxins (e.g., waglerins and azemiopsin), which are found in hemotoxic venoms. Other neurotoxins from hemotoxic venoms include baptides, crotamine, cysteine-rich secretory proteins, Kunitz-type protease inhibitors, sarafotoxins and three-finger toxins. Some of these toxins exhibit postsynaptic activity, while others affect the functioning of voltage-dependent ion channels. This review represents the first attempt to systematize data on the neurotoxins from "non-neurotoxic" snake venom. The structural and functional characteristic of these neurotoxins affecting diverse targets in the nervous system are considered.
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The Phospholipase Activity of Ammodytoxin, a Prototype Snake Venom β-Neurotoxin, Is Not Obligatory for Cell Internalisation and Translocation to Mitochondria. Toxins (Basel) 2022; 14:toxins14060375. [PMID: 35737036 PMCID: PMC9228470 DOI: 10.3390/toxins14060375] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/11/2022] [Accepted: 05/26/2022] [Indexed: 02/04/2023] Open
Abstract
β-Neurotoxins are secreted phospholipase A2 molecules that inhibit transmission in neuromuscular synapses by poisoning the motor neurons. These toxins specifically and rapidly internalise into the nerve endings of motor neurons. Ammodytoxin (Atx) is a prototype β-neurotoxin from the venom of the nose-horned viper (Vipera ammodytes ammodytes). Here, we studied the relevance of the enzymatic activity of Atx in cell internalisation and subsequent intracellular movement using transmission electron microscopy (TEM). We prepared a recombinant, enzymatically inactive mutant of Atx, Atx(D49S), labelled with gold nanoparticles (GNP), and incubated this with PC12 cells, to analyse its localisation by TEM. Atx(D49S)-GNP internalised into the cells. Inside the cells, Atx(D49S)-GNP was detected in different vesicle-like structures, cytosol, endoplasmic reticulum and mitochondria, where it was spotted in the intermembrane space and matrix. Co-localization of fluorescently labelled Atx(D49S) with mitochondria in PC12 cells by confocal fluorescence microscopy confirmed the reliability of results generated using Atx(D49S)-GNP and TEM and allowed us to conclude that the phospholipase activity of Atx is not obligatory for its cell internalisation and translocation into the mitochondrial intermembrane space and matrix.
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Santos NFTD, Imberg ADS, Mariano DOC, Moraes ACD, Andrade-Silva J, Fernandes CM, Sobral AC, Giannotti KC, Kuwabara WMT, Pimenta DC, Maria DA, Sandoval MRL, Afeche SC. β-micrustoxin (Mlx-9), a PLA2 from Micrurus lemniscatus snake venom: biochemical characterization and anti-proliferative effect mediated by p53. J Venom Anim Toxins Incl Trop Dis 2022; 28:e20210094. [PMID: 35432496 PMCID: PMC9008913 DOI: 10.1590/1678-9199-jvatitd-2021-0094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Endogenous phospholipases A2 (PLA2) play a fundamental role in inflammation, neurodegenerative diseases, apoptosis and cellular senescence. Neurotoxins with PLA2 activity are found in snake venoms from the Elapidae and Viperidae families. The mechanism of action of these neurotoxins have been studied using hippocampal and cerebellar neuronal cultures showing [Ca2+]i increase, mitochondrial depolarization and cell death. Astrocytes are rarely used as a model, despite being modulators at the synapses and responsible for homeostasis and defense in the central nervous system. Preserving the cell division ability, they can be utilized to study the cell proliferation process. In the present work cultured astrocytes and glioblastoma cells were employed to characterize the action of β-micrustoxin (previously named Mlx-9), a PLA2 isolated from Micrurus lemniscatus snake venom. The β-micrustoxin structure was determined and the cell proliferation, cell cycle phases and the regulatory proteins p53, p21 and p27 were investigated. Methods β-micrustoxin was characterized biochemically by a proteomic approach. Astrocytes were obtained by dissociation of pineal glands from Wistar rats; glioblastoma tumor cells were purchased from ATCC and Sigma and cultured in DMEM medium. Cell viability was evaluated by MTT assay; cell proliferation and cell cycle phases were analyzed by flow cytometry; p53, p21 and p27 proteins were studied by western blotting and immunocytochemistry. Results Proteomic analysis revealed fragments on β-micrustoxin that aligned with a PLA2 from Micrurus lemniscatus lemniscatus previously identified as transcript ID DN112835_C3_g9_i1/m.9019. β-micrustoxin impaired the viability of astrocytes and glioblastoma tumor cells. There was a reduction in cell proliferation, an increase in G2/M phase and activation of p53, p21 and p27 proteins in astrocytes. Conclusion These findings indicate that β-micrustoxin from Micrurus lemniscatus venom could inhibit cell proliferation through p53, p21 and p27 activation thus imposing cell cycle arrest at the checkpoint G2/M.
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Pungerčar J, Bihl F, Lambeau G, Križaj I. What do secreted phospholipases A 2 have to offer in combat against different viruses up to SARS-CoV-2? Biochimie 2021; 189:40-50. [PMID: 34097986 PMCID: PMC8449419 DOI: 10.1016/j.biochi.2021.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/24/2021] [Accepted: 05/31/2021] [Indexed: 12/09/2022]
Abstract
Secreted phospholipases A2 (sPLA2s) form a widespread group of structurally-related enzymes that catalyse the hydrolysis of the sn-2 ester bond of glycerophospholipids to produce free fatty acids and lysophospholipids. In humans, nine catalytically active and two inactive sPLA2 proteins have been identified. These enzymes play diverse biological roles, including host defence against bacteria, parasites and viruses. Several of these endogenous sPLA2s may play a defensive role in viral infections, as they display in vitro antiviral activity by both direct and indirect mechanisms. However, endogenous sPLA2s may also exert an offensive and negative role, dampening the antiviral response or promoting inflammation in animal models of viral infection. Similarly, several exogenous sPLA2s, most of them from snake venoms and other animal venoms, possess in vitro antiviral activities. Thus, both endogenous and exogenous sPLA2s may be exploited for the development of new antiviral substances or as therapeutic targets for antagonistic drugs that may promote a more robust antiviral response. In this review, the antiviral versus proviral role of both endogenous and exogenous sPLA2s against various viruses including coronaviruses is presented. Based on the highlighted developments in this area of research, possible directions of future investigation are envisaged. One of them is also a possibility of exploiting sPLA2s as biological markers of the severity of the Covid-19 pandemic caused by SARS-CoV-2 infection.
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Affiliation(s)
- Jože Pungerčar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
| | - Franck Bihl
- Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR7275, Valbonne Sophia Antipolis, France
| | - Gérard Lambeau
- Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR7275, Valbonne Sophia Antipolis, France.
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
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Madhushani U, Isbister GK, Tasoulis T, Hodgson WC, Silva A. In-Vitro Neutralization of the Neurotoxicity of Coastal Taipan Venom by Australian Polyvalent Antivenom: The Window of Opportunity. Toxins (Basel) 2020; 12:toxins12110690. [PMID: 33142783 PMCID: PMC7694127 DOI: 10.3390/toxins12110690] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 12/17/2022] Open
Abstract
Coastal taipan (Oxyuranus scutellatus) envenoming causes life-threatening neuromuscular paralysis in humans. We studied the time period during which antivenom remains effective in preventing and arresting in vitro neuromuscular block caused by taipan venom and taipoxin. Venom showed predominant pre-synaptic neurotoxicity at 3 µg/mL and post-synaptic neurotoxicity at 10 µg/mL. Pre-synaptic neurotoxicity was prevented by addition of Australian polyvalent antivenom before the venom and taipoxin and, reversed when antivenom was added 5 min after venom and taipoxin. Antivenom only partially reversed the neurotoxicity when added 15 min after venom and had no significant effect when added 30 min after venom. In contrast, post-synaptic activity was fully reversed when antivenom was added 30 min after venom. The effect of antivenom on pre-synaptic neuromuscular block was reproduced by washing the bath at similar time intervals for 3 µg/mL, but not for 10 µg/mL. We found an approximate 10–15 min time window in which antivenom can prevent pre-synaptic neuromuscular block. This time window is likely to be longer in envenomed patients due to the delay in venom absorption. Similar effectiveness of antivenom and washing with 3 µg/mL venom suggests that antivenom most likely acts by neutralizing pre-synaptic toxins before they interfere with neurotransmission inside the motor nerve terminals.
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Affiliation(s)
- Umesha Madhushani
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka;
| | - Geoffrey K. Isbister
- Clinical Toxicology Research Group, University of Newcastle, Callaghan 2308, Australia; (G.K.I.); (T.T.)
| | - Theo Tasoulis
- Clinical Toxicology Research Group, University of Newcastle, Callaghan 2308, Australia; (G.K.I.); (T.T.)
| | - Wayne C. Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton 3800, Australia;
| | - Anjana Silva
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka;
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton 3800, Australia;
- Correspondence:
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Williams HF, Layfield HJ, Vallance T, Patel K, Bicknell AB, Trim SA, Vaiyapuri S. The Urgent Need to Develop Novel Strategies for the Diagnosis and Treatment of Snakebites. Toxins (Basel) 2019; 11:E363. [PMID: 31226842 PMCID: PMC6628419 DOI: 10.3390/toxins11060363] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023] Open
Abstract
Snakebite envenoming (SBE) is a priority neglected tropical disease, which kills in excess of 100,000 people per year. Additionally, many millions of survivors also suffer through disabilities and long-term health consequences. The only treatment for SBE, antivenom, has a number of major associated problems, not least, adverse reactions and limited availability. This emphasises the necessity for urgent improvements to the management of this disease. Administration of antivenom is too frequently based on symptomatology, which results in wasting crucial time. The majority of SBE-affected regions rely on broad-spectrum polyvalent antivenoms that have a low content of case-specific efficacious immunoglobulins. Research into small molecular therapeutics such as varespladib/methyl-varespladib (PLA2 inhibitors) and batimastat/marimastat (metalloprotease inhibitors) suggest that such adjunctive treatments could be hugely beneficial to victims. Progress into toxin-specific monoclonal antibodies as well as alternative binding scaffolds such as aptamers hold much promise for future treatment strategies. SBE is not implicit during snakebite, due to venom metering. Thus, the delay between bite and symptom presentation is critical and when symptoms appear it may often already be too late to effectively treat SBE. The development of reliable diagnostical tools could therefore initiate a paradigm shift in the treatment of SBE. While the complete eradication of SBE is an impossibility, mitigation is in the pipeline, with new treatments and diagnostics rapidly emerging. Here we critically review the urgent necessity for the development of diagnostic tools and improved therapeutics to mitigate the deaths and disabilities caused by SBE.
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Affiliation(s)
| | | | - Thomas Vallance
- School of Pharmacy, University of Reading, Reading RG6 6AH, UK.
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
| | - Andrew B Bicknell
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
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Neurotoxicity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom. Arch Toxicol 2019; 93:2065-2086. [PMID: 31123802 DOI: 10.1007/s00204-019-02476-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
Abstract
We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom.
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Leonardi A, Sajevic T, Pungerčar J, Križaj I. Comprehensive Study of the Proteome and Transcriptome of the Venom of the Most Venomous European Viper: Discovery of a New Subclass of Ancestral Snake Venom Metalloproteinase Precursor-Derived Proteins. J Proteome Res 2019; 18:2287-2309. [PMID: 31017792 PMCID: PMC6727599 DOI: 10.1021/acs.jproteome.9b00120] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
nose-horned viper, its nominotypical subspecies Vipera
ammodytes ammodytes (Vaa), in particular,
is, medically, one of the most relevant snakes in Europe. The local
and systemic clinical manifestations of poisoning by the venom of
this snake are the result of the pathophysiological effects inflicted
by enzymatic and nonenzymatic venom components acting, most prominently,
on the blood, cardiovascular, and nerve systems. This venom is a very
complex mixture of pharmacologically active proteins and peptides.
To help improve the current antivenom therapy toward higher specificity
and efficiency and to assist drug discovery, we have constructed,
by combining transcriptomic and proteomic analyses, the most comprehensive
library yet of the Vaa venom proteins and peptides.
Sequence analysis of the venom gland cDNA library has revealed the
presence of messages encoding 12 types of polypeptide precursors.
The most abundant are those for metalloproteinase inhibitors (MPis),
bradykinin-potentiating peptides (BPPs), and natriuretic peptides
(NPs) (all three on a single precursor), snake C-type lectin-like
proteins (snaclecs), serine proteases (SVSPs), P-II and P-III metalloproteinases
(SVMPs), secreted phospholipases A2 (sPLA2s),
and disintegrins (Dis). These constitute >88% of the venom transcriptome.
At the protein level, 57 venom proteins belonging to 16 different
protein families have been identified and, with SVSPs, sPLA2s, snaclecs, and SVMPs, comprise ∼80% of all venom proteins.
Peptides detected in the venom include NPs, BPPs, and inhibitors of
SVSPs and SVMPs. Of particular interest, a transcript coding for a
protein similar to P-III SVMPs but lacking the MP domain was also
found at the protein level in the venom. The existence of such proteins,
also supported by finding similar venom gland transcripts in related
snake species, has been demonstrated for the first time, justifying
the proposal of a new P-IIIe subclass of ancestral SVMP precursor-derived
proteins.
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Affiliation(s)
- Adrijana Leonardi
- Department of Molecular and Biomedical Sciences , Jožef Stefan Institute , Jamova cesta 39 , SI-1000 Ljubljana , Slovenia
| | - Tamara Sajevic
- Department of Molecular and Biomedical Sciences , Jožef Stefan Institute , Jamova cesta 39 , SI-1000 Ljubljana , Slovenia
| | - Jože Pungerčar
- Department of Molecular and Biomedical Sciences , Jožef Stefan Institute , Jamova cesta 39 , SI-1000 Ljubljana , Slovenia
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences , Jožef Stefan Institute , Jamova cesta 39 , SI-1000 Ljubljana , Slovenia
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Revin VV, Pinyaev SI, Parchaykina MV, Revina ES, Maksimov GV, Kuzmenko TP. The Effect of Resveratrol on the Composition and State of Lipids and the Activity of Phospholipase A 2 During the Excitation and Regeneration of Somatic Nerves. Front Physiol 2019; 10:384. [PMID: 31057413 PMCID: PMC6482430 DOI: 10.3389/fphys.2019.00384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/21/2019] [Indexed: 12/27/2022] Open
Abstract
It has been shown that in the somatic nerve's lipids, both during excitation and transection, changes occur with the composition of individual phospholipids and in phospholipids fatty acids, which changes the phase state of the myelin and nerve fiber axolemma lipid bilayer. A main contribution in the nerve degenerative processes is dependent on the composition phospholipid's fatty acid changes during the activation of both Ca2+-dependent and Ca2+-independent phospholipase A2 forms. At the same time, we studded changes in phosphoinisitol (PI) and diacylglycerol (DAG), which depend on the phosphoinositide cycle function during nerve excitation and degeneration processes. It was found that myelin lipids and nerve fiber axolemmas are involved not only in the functioning of the peripheral nerves, but also the pathological processes underlying deep functional and structural disorders. The effect of resveratrol on regeneration processes in the damaged rat sciatic nerve has also been investigated.
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Affiliation(s)
- Victor Vasilevich Revin
- Department of Biotechnology, Bioengineering and Biochemistry, National Research Ogarev Mordovia State University, Saransk, Russia
| | - Sergey Ivanovich Pinyaev
- Department of Biotechnology, Bioengineering and Biochemistry, National Research Ogarev Mordovia State University, Saransk, Russia
| | - Marina Vladimirovna Parchaykina
- Department of Biotechnology, Bioengineering and Biochemistry, National Research Ogarev Mordovia State University, Saransk, Russia
| | - Elvira Sergeevna Revina
- Department of Biotechnology, Bioengineering and Biochemistry, National Research Ogarev Mordovia State University, Saransk, Russia
| | | | - Tatyana Pavlovna Kuzmenko
- Department of Biotechnology, Bioengineering and Biochemistry, National Research Ogarev Mordovia State University, Saransk, Russia
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Kovyazina IV, Kopylova NV, Utkin YN, Bukharaeva EA, Nikolsky EE, Vulfius CA. Depression of the Evoked Quantal Acetylcholine Secretion in Frog Neuromuscular Junction by Phospholipases A2 from the Venom of Steppe Viper Vipera ursiniirenardi. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2019; 13:78-84. [DOI: 10.1134/s1990747819010069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/03/2018] [Accepted: 05/07/2018] [Indexed: 05/14/2025]
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15
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An in vitro potency assay using nicotinic acetylcholine receptor binding works well with antivenoms against Bungarus candidus and Naja naja. Sci Rep 2018; 8:9716. [PMID: 29946111 PMCID: PMC6018763 DOI: 10.1038/s41598-018-27794-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/29/2018] [Indexed: 12/19/2022] Open
Abstract
In order to facilitate/expedite the production of effective and affordable snake antivenoms, a novel in vitro potency assay was previously developed. The assay is based on an antiserum’s ability to bind to postsynaptic neurotoxin (PSNT) and thereby inhibit the PSNT binding to the nicotinic acetylcholine receptor (nAChR). The assay was shown to work well with antiserum against Thai Naja kaouthia which produces predominantly the lethal PSNTs. In this work, the assay is demonstrated to work well with antiserum/antivenom against Bungarus candidus (BC), which also produces lethal presynaptic neurotoxins, as well as antivenom against Sri Lankan Naja naja (NN), which produces an abundance of cytotoxins. The in vitro and in vivo median effective ratios (ER50s) for various batches of antisera against BC showed a correlation (R2) of 0.8922 (p < 0.001) while the corresponding value for the anti-NN antivenom was R2 = 0.7898 (p < 0.01). These results, together with the known toxin profiles of various genera of elapids, suggest that this in vitro assay could be used with antisera against other species of Bungarus and Naja and possibly other neurotoxic snake venoms worldwide. The assay should significantly save numerous lives of mice and accelerate production of life-saving antivenoms.
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Makarova YV, Kryukova EV, Shelukhina IV, Lebedev DS, Andreeva TV, Ryazantsev DY, Balandin SV, Ovchinnikova TV, Tsetlin VI, Utkin YN. The First Recombinant Viper Three-Finger Toxins: Inhibition of Muscle and Neuronal Nicotinic Acetylcholine Receptors. DOKL BIOCHEM BIOPHYS 2018; 479:127-130. [PMID: 29779115 DOI: 10.1134/s1607672918020205] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Indexed: 12/14/2022]
Abstract
Genes encoding two three-finger toxins TFT-AF and TFT-VN, nucleotide sequences of which were earlier determined by cloning cDNA from venom glands of vipers Azemiops feae and Vipera nikolskii, respectively, were expressed for the first time in E. coli cells. The biological activity of these toxins was studied by electrophysiological techniques, calcium imaging, and radioligand analysis. It was shown for the first time that viper three-finger toxins are antagonists of nicotinic acetylcholine receptors of neuronal and muscle type.
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Affiliation(s)
- Ya V Makarova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - E V Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - I V Shelukhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - D S Lebedev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - T V Andreeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - D Yu Ryazantsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - S V Balandin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - T V Ovchinnikova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Sechenov First Moscow State Medical University, Ministry of Healthcare of the Russian Federation, Moscow, 119992, Russia
| | - V I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Yu N Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
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Neuromuscular effect of venoms from adults and juveniles of Crotalus durissus cumanensis (Humboldt, 1811) from Guajira, Colombia. Toxicon 2017; 139:41-44. [PMID: 28978413 DOI: 10.1016/j.toxicon.2017.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 09/22/2017] [Accepted: 09/30/2017] [Indexed: 11/22/2022]
Abstract
A toxinological study was performed to compare the neuromuscular effect of venom from adult and juvenile specimens from Crotalus durissus cumanensis from Guajira, Colombia. Both venoms exhibited neurotoxic activity in chick biventer cervicis nerve-muscle preparation. In addition, venom from juveniles was faster than adults to produce a neuromuscular blockade. In the contrary to the venom from juvenile's, at high doses, adult's venom affected the ACh and KCl contractures, indicating a myotoxic effect.
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18
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Snake Venom PLA 2, a Promising Target for Broad-Spectrum Antivenom Drug Development. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6592820. [PMID: 29318152 PMCID: PMC5727668 DOI: 10.1155/2017/6592820] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/30/2017] [Indexed: 12/04/2022]
Abstract
Snakebite envenomation is a neglected global health problem, causing substantial mortality, disability, and psychological morbidity, especially in rural tropical and subtropical zones. Antivenin is currently the only specific medicine for envenomation. However, it is restricted by cold storage, snakebite diagnosis, and high price. Snake venom phospholipase A2s (svPLA2s) are found in all kinds of venomous snake families (e.g., Viperidae, Elapidae, and Colubridae). Along with their catalytic activity, svPLA2s elicit a wide variety of pharmacological effects that play a pivotal role in envenomation damage. Hence, neutralization of the svPLA2s could weaken or inhibit toxic damage. Here we overviewed the latest knowledge on the distribution, pathophysiological effects, and inhibitors of svPLA2s to elucidate the potential for a novel, wide spectrum antivenom drug targeting svPLA2s.
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Abstract
Snakebite envenoming is a neglected tropical disease that kills >100,000 people and maims >400,000 people every year. Impoverished populations living in the rural tropics are particularly vulnerable; snakebite envenoming perpetuates the cycle of poverty. Snake venoms are complex mixtures of proteins that exert a wide range of toxic actions. The high variability in snake venom composition is responsible for the various clinical manifestations in envenomings, ranging from local tissue damage to potentially life-threatening systemic effects. Intravenous administration of antivenom is the only specific treatment to counteract envenoming. Analgesics, ventilator support, fluid therapy, haemodialysis and antibiotic therapy are also used. Novel therapeutic alternatives based on recombinant antibody technologies and new toxin inhibitors are being explored. Confronting snakebite envenoming at a global level demands the implementation of an integrated intervention strategy involving the WHO, the research community, antivenom manufacturers, regulatory agencies, national and regional health authorities, professional health organizations, international funding agencies, advocacy groups and civil society institutions.
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Affiliation(s)
- José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, PO Box 11501-2060, San José, Costa Rica
| | - Juan J Calvete
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | | | - Robert A Harrison
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David J Williams
- Charles Campbell Toxinology Centre, School of Medicine &Health Sciences, University of Papua New Guinea, Boroko, National Capital District, Papua New Guinea
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - David A Warrell
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
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20
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Ratanabanangkoon K, Simsiriwong P, Pruksaphon K, Tan KY, Eursakun S, Tan CH, Chantrathonkul B, Wongwadhunyoo W, Youngchim S, Tan NH. A novel in vitro potency assay of antisera against Thai Naja kaouthia based on nicotinic acetylcholine receptor binding. Sci Rep 2017; 7:8545. [PMID: 28819275 PMCID: PMC5561211 DOI: 10.1038/s41598-017-08962-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 07/17/2017] [Indexed: 11/30/2022] Open
Abstract
Snake envenomation is an important medical problem. One of the hurdles in antivenom development is the in vivo assay of antivenom potency which is expensive, gives variable results and kills many animals. We report a novel in vitro assay involving the specific binding of the postsynaptic neurotoxins (PSNTs) of elapid snakes with purified Torpedo californica nicotinic acetylcholine receptor (nAChR). The potency of an antivenom is determined by its antibody ability to bind and neutralize the PSNT, thus preventing it from binding to nAChR. The PSNT of Naja kaouthia (NK3) was immobilized on microtiter wells and nAChR was added to bind with it. The in vitro IC50 of N. kaouthia venom that inhibited 50% of nAChR binding to the immobilized NK3 was determined. Varying concentrations of antisera against N. kaouthia were separately pre-incubated with 5xIC50 of N. kaouthia venom. The remaining free NK3 were incubated with nAChR before adding to the NK3 coated plates. The in vitro and in vivo median effective ratio, ER50s of 12 batches of antisera showed correlation (R 2) of 0.9809 (p < 0.0001). This in vitro assay should be applicable to antisera against other elapid venoms and should reduce the use of live animals and accelerate development of life-saving antivenoms.
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Affiliation(s)
- Kavi Ratanabanangkoon
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
- Chulabhorn Graduate Institute, Bangkok, 10210 Thailand
- Department of Microbiology, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok, 10400 Thailand
| | | | - Kritsada Pruksaphon
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kae Yi Tan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603 Malaysia
| | - Sukanya Eursakun
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Choo Hock Tan
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603 Malaysia
| | | | | | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nget Hong Tan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603 Malaysia
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21
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Xiong S, Luo Y, Zhong L, Xiao H, Pan H, Liao K, Yang M, Huang C. Investigation of the inhibitory potential of phospholipase A 2 inhibitor gamma from Sinonatrix annularis to snake envenomation. Toxicon 2017; 137:83-91. [PMID: 28746861 DOI: 10.1016/j.toxicon.2017.07.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 11/28/2022]
Abstract
SaPLIγ is a novel gamma phospholipase A2 inhibitor (PLI) recently isolated from Sinonatrix annularis, a Chinese endemic non-venomous snake. To explore the neutralization effects of saPLIγ in snakebite envenomation, a dose equivalent to LD50 of Deinagkistrodon acutus, Agkistrodon halys and Naja atra venom with/without saPLIγ was inoculated into the gastrocnemius muscle of female Kunming mice. The ability of saPLIγ to inhibit myonecrosis and systemic toxicity were evaluated through investigations of muscle histopathology, and determination of the serum levels of creatine kinase (CK), lactate dehydrogenase isoenzyme1 (LDH1) and aspartate transferase (AST). Edema of the gastrocnemius muscle was evaluated by calculating the width difference between the inoculated limb and the contralateral leg. Desmin loss in the gastrocnemius muscle was determined by Western blot analysis. Co-immunoprecipitation and shotgun LC-MS/MS analyses were performed to identify venom proteins that interact with saPLIγ. All the envenomed mice had significantly elevated serum CK, LDH1 and AST levels, whereas the levels were decreased significantly in the presence of saPLIγ. Histopathological evaluation of gastrocnemius muscle sections showed severe snake venom-induced damage, characterized by leukocyte infiltration and erythrocyte leakage, leading to local edema. Myonecrosis, hemorrhage and desmin loss were significantly attenuated by saPLIγ. SaPLIγ interacted with a wide range of venom proteins, including PLA2s, metalloproteinases and C type lectins, which may contribute to broad anti-venom effects.
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Affiliation(s)
- Shengwei Xiong
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Yunyun Luo
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Lipeng Zhong
- The Fourth Affiliated Hospital, Nanchang University, Nanchang, 330006, China
| | - Huixiang Xiao
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Hong Pan
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Keren Liao
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Mengxue Yang
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Chunhong Huang
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China; Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Nanchang University, Nanchang, 330006, China.
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22
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Rey-Suárez P, Núñez V, Saldarriaga-Córdoba M, Lomonte B. Primary structures and partial toxicological characterization of two phospholipases A 2 from Micrurus mipartitus and Micrurus dumerilii coral snake venoms. Biochimie 2017; 137:88-98. [DOI: 10.1016/j.biochi.2017.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/13/2017] [Indexed: 10/20/2022]
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Rodrigo C, Kirushanthan S, Gnanathasan A. Prevention of krait bites by sleeping above ground: preliminary results from an observational pilot study. J Occup Med Toxicol 2017; 12:10. [PMID: 28352289 PMCID: PMC5368888 DOI: 10.1186/s12995-017-0156-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/23/2017] [Indexed: 11/18/2022] Open
Abstract
Introduction Neurotoxic envenoming following the bites of kraits (Bungarus spp.) is a common cause of death in the dry zone of Sri Lanka and elsewhere in South Asia. Most of these bites occur at night and are inflicted on people sleeping on the ground. Thus we hypothesized that the simple measure of sleeping above ground would help to reduce the number of observed krait bites. Methods This study was conducted in two villages of the Kilinochchi district of Sri Lanka which had reported a high number of krait bites in the two years preceding the study. Most of the residents in these two villages slept on the ground. Residents in one area were given beds free of charge, using funds available from the study. Both villages received health education on the prevention of krait bites. Results Forty five beds were distributed to 45 families in one village. This enabled 115 individuals to sleep above ground level. 6 monthly follow up visits were conducted ensuring the proper utilization of beds. Follow up was continued for 30 months (September 2013–March 2016); during this time period no krait bites were reported in either area. Conclusions We observed a dramatic decline of krait bites in both villages. Better awareness with effective health education and clearing of vegetation could have led to the decline in the number of krait bites in both villages.
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Affiliation(s)
- Chaturaka Rodrigo
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka
| | | | - Ariaranee Gnanathasan
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka
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24
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Fernandes CAH, Pazin WM, Dreyer TR, Bicev RN, Cavalcante WLG, Fortes-Dias CL, Ito AS, Oliveira CLP, Fernandez RM, Fontes MRM. Biophysical studies suggest a new structural arrangement of crotoxin and provide insights into its toxic mechanism. Sci Rep 2017; 7:43885. [PMID: 28256632 PMCID: PMC5335569 DOI: 10.1038/srep43885] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/31/2017] [Indexed: 11/19/2022] Open
Abstract
Crotoxin (CTX) is the main neurotoxin found in Crotalus durissus rattlesnake venoms being composed by a nontoxic and non-enzymatic component (CA) and a toxic phospholipase A2 (CB). Previous crystallographic structures of CTX and CB provided relevant insights: (i) CTX structure showed a 1:1 molecular ratio between CA and CB, presenting three tryptophan residues in the CA/CB interface and one exposed to solvent; (ii) CB structure displayed a tetrameric conformation. This study aims to provide further information on the CTX mechanism of action by several biophysical methods. Our data show that isolated CB can in fact form tetramers in solution; however, these tetramers can be dissociated by CA titration. Furthermore, CTX exhibits a strong reduction in fluorescence intensity and lifetime compared with isolated CA and CB, suggesting that all tryptophan residues in CTX may be hidden by the CA/CB interface. By companying spectroscopy fluorescence and SAXS data, we obtained a new structural model for the CTX heterodimer in which all tryptophans are located in the interface, and the N-terminal region of CB is largely exposed to the solvent. Based on this model, we propose a toxic mechanism of action for CTX, involving the interaction of N-terminal region of CB with the target before CA dissociation.
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Affiliation(s)
- Carlos A. H. Fernandes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil
| | - Wallance M. Pazin
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, USP, Ribeirão Preto-SP, Brazil
| | - Thiago R. Dreyer
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil
| | - Renata N. Bicev
- Departamento de Física Experimental, Instituto de Física, Universidade de São Paulo – USP, São Paulo, SP, Brazil
| | - Walter L. G. Cavalcante
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil
- Departamento de Farmacologia, Instituto de Ciências Biológicas, UFMG, Belo Horizonte, MG, Brazil
| | - Consuelo L. Fortes-Dias
- Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil
| | - Amando S. Ito
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, USP, Ribeirão Preto-SP, Brazil
| | - Cristiano L. P. Oliveira
- Departamento de Física Experimental, Instituto de Física, Universidade de São Paulo – USP, São Paulo, SP, Brazil
| | - Roberto Morato Fernandez
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil
| | - Marcos R. M. Fontes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil
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25
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Resende L, Almeida J, Schezaro-Ramos R, Collaço R, Simioni L, Ramírez D, González W, Soares A, Calderon L, Marangoni S, da Silva S. Exploring and understanding the functional role, and biochemical and structural characteristics of an acidic phospholipase A2, AplTx-I, purified from Agkistrodon piscivorus leucostoma snake venom. Toxicon 2017; 127:22-36. [DOI: 10.1016/j.toxicon.2017.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 11/28/2016] [Accepted: 01/03/2017] [Indexed: 12/15/2022]
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26
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Ratanabanangkoon K, Tan KY, Eursakun S, Tan CH, Simsiriwong P, Pamornsakda T, Wiriyarat W, Klinpayom C, Tan NH. A Simple and Novel Strategy for the Production of a Pan-specific Antiserum against Elapid Snakes of Asia. PLoS Negl Trop Dis 2016; 10:e0004565. [PMID: 27058956 PMCID: PMC4825939 DOI: 10.1371/journal.pntd.0004565] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/01/2016] [Indexed: 11/18/2022] Open
Abstract
Snakebite envenomation is a serious medical problem in many tropical developing countries and was considered by WHO as a neglected tropical disease. Antivenom (AV), the rational and most effective treatment modality, is either unaffordable and/or unavailable in many affected countries. Moreover, each AV is specific to only one (monospecific) or a few (polyspecific) snake venoms. This demands that each country to prepare AV against its local snake venoms, which is often not feasible. Preparation of a 'pan-specific' AV against many snakes over a wide geographical area in some countries/regions has not been possible. If a 'pan-specific' AV effective against a variety of snakes from many countries could be prepared, it could be produced economically in large volume for use in many countries and save many lives. The aim of this study was to produce a pan-specific antiserum effective against major medically important elapids in Asia. The strategy was to use toxin fractions (TFs) of the venoms in place of crude venoms in order to reduce the number of antigens the horses were exposed to. This enabled inclusion of a greater variety of elapid venoms in the immunogen mix, thus exposing the horse immune system to a diverse repertoire of toxin epitopes, and gave rise to antiserum with wide paraspecificity against elapid venoms. Twelve venom samples from six medically important elapid snakes (4 Naja spp. and 2 Bungarus spp.) were collected from 12 regions/countries in Asia. Nine of these 12 venoms were ultra-filtered to remove high molecular weight, non-toxic and highly immunogenic proteins. The remaining 3 venoms were not ultra-filtered due to limited amounts available. The 9 toxin fractions (TFs) together with the 3 crude venoms were emulsified in complete Freund's adjuvant and used to immunize 3 horses using a low dose, low volume, multisite immunization protocol. The horse antisera were assayed by ELISA and by in vivo lethality neutralization in mice. The findings were: a) The 9 TFs were shown to contain all of the venom toxins but were devoid of high MW proteins. When these TFs, together with the 3 crude venoms, were used as the immunogen, satisfactory ELISA antibody titers against homologous/heterologous venoms were obtained. b) The horse antiserum immunologically reacted with and neutralized the lethal effects of both the homologous and the 16 heterologous Asian/African elapid venoms tested. Thus, the use of TFs in place of crude venoms and the inclusion of a variety of elapid venoms in the immunogen mix resulted in antiserum with wide paraspecificity against elapid venoms from distant geographic areas. The antivenom prepared from this antiserum would be expected to be pan-specific and effective in treating envenomations by most elapids in many Asian countries. Due to economies of scale, the antivenom could be produced inexpensively and save many lives. This simple strategy and procedure could be readily adapted for the production of pan-specific antisera against elapids of other continents.
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Affiliation(s)
- Kavi Ratanabanangkoon
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
- Chulabhorn Graduate Institute, Bangkok, Thailand
- * E-mail:
| | - Kae Yi Tan
- Department of Molecular Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sukanya Eursakun
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Choo Hock Tan
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Teeraporn Pamornsakda
- Department of Pre-clinic and Applied Animal Science, Faculty of Veterinary Science, Mahidol University, Salaya, NakornPrathom, Thailand
| | - Witthawat Wiriyarat
- Department of Pre-clinic and Applied Animal Science, Faculty of Veterinary Science, Mahidol University, Salaya, NakornPrathom, Thailand
| | - Chaiya Klinpayom
- The Veterinary and Remount Department, The Royal Thai Army, NakornPrathom, Thailand
| | - Nget Hong Tan
- Department of Molecular Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Carregari VC, Dai J, Verano-Braga T, Rocha T, Ponce-Soto LA, Marangoni S, Roepstorff P. Revealing the functional structure of a new PLA2 K49 from Bothriopsis taeniata snake venom employing automatic “de novo” sequencing using CID/HCD/ETD MS/MS analyses. J Proteomics 2016; 131:131-139. [DOI: 10.1016/j.jprot.2015.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022]
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Snake and Spider Toxins Induce a Rapid Recovery of Function of Botulinum Neurotoxin Paralysed Neuromuscular Junction. Toxins (Basel) 2015; 7:5322-36. [PMID: 26670253 PMCID: PMC4690137 DOI: 10.3390/toxins7124887] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/20/2015] [Accepted: 11/30/2015] [Indexed: 12/29/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) and some animal neurotoxins (β-Bungarotoxin, β-Btx, from elapid snakes and α-Latrotoxin, α-Ltx, from black widow spiders) are pre-synaptic neurotoxins that paralyse motor axon terminals with similar clinical outcomes in patients. However, their mechanism of action is different, leading to a largely-different duration of neuromuscular junction (NMJ) blockade. BoNTs induce a long-lasting paralysis without nerve terminal degeneration acting via proteolytic cleavage of SNARE proteins, whereas animal neurotoxins cause an acute and complete degeneration of motor axon terminals, followed by a rapid recovery. In this study, the injection of animal neurotoxins in mice muscles previously paralyzed by BoNT/A or /B accelerates the recovery of neurotransmission, as assessed by electrophysiology and morphological analysis. This result provides a proof of principle that, by causing the complete degeneration, reabsorption, and regeneration of a paralysed nerve terminal, one could favour the recovery of function of a biochemically- or genetically-altered motor axon terminal. These observations might be relevant to dying-back neuropathies, where pathological changes first occur at the neuromuscular junction and then progress proximally toward the cell body.
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Floriano RS, Rocha T, Carregari VC, Marangoni S, da Cruz-Höfling MA, Hyslop S, Rodrigues-Simioni L, Rowan EG. The neuromuscular activity of Bothriopsis bilineata smaragdina (forest viper) venom and its toxin Bbil-TX (Asp49 phospholipase A2) on isolated mouse nerve-muscle preparations. Toxicon 2015; 96:24-37. [DOI: 10.1016/j.toxicon.2015.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 12/30/2014] [Accepted: 01/03/2015] [Indexed: 11/16/2022]
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Mitochondrial alarmins released by degenerating motor axon terminals activate perisynaptic Schwann cells. Proc Natl Acad Sci U S A 2015; 112:E497-505. [PMID: 25605902 DOI: 10.1073/pnas.1417108112] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An acute and highly reproducible motor axon terminal degeneration followed by complete regeneration is induced by some animal presynaptic neurotoxins, representing an appropriate and controlled system to dissect the molecular mechanisms underlying degeneration and regeneration of peripheral nerve terminals. We have previously shown that nerve terminals exposed to spider or snake presynaptic neurotoxins degenerate as a result of calcium overload and mitochondrial failure. Here we show that toxin-treated primary neurons release signaling molecules derived from mitochondria: hydrogen peroxide, mitochondrial DNA, and cytochrome c. These molecules activate isolated primary Schwann cells, Schwann cells cocultured with neurons and at neuromuscular junction in vivo through the MAPK pathway. We propose that this inter- and intracellular signaling is involved in triggering the regeneration of peripheral nerve terminals affected by other forms of neurodegenerative diseases.
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Yang ZM, Guo Q, Ma ZR, Chen Y, Wang ZZ, Wang XM, Wang YM, Tsai IH. Structures and functions of crotoxin-like heterodimers and acidic phospholipases A2 from Gloydius intermedius venom: Insights into the origin of neurotoxic-type rattlesnakes. J Proteomics 2015; 112:210-23. [DOI: 10.1016/j.jprot.2014.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/02/2014] [Accepted: 09/15/2014] [Indexed: 01/15/2023]
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Vulfius CA, Kasheverov IE, Starkov VG, Osipov AV, Andreeva TV, Filkin SY, Gorbacheva EV, Astashev ME, Tsetlin VI, Utkin YN. Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2. PLoS One 2014; 9:e115428. [PMID: 25522251 PMCID: PMC4270787 DOI: 10.1371/journal.pone.0115428] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 11/24/2014] [Indexed: 01/29/2023] Open
Abstract
Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.
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Affiliation(s)
- Catherine A. Vulfius
- Institute of Cell Biophysics, Russian Academy of Sciences, Ul. Institutskaya 3, Pushchino, Moscow Region 142290, Russia
| | - Igor E. Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Vladislav G. Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Alexey V. Osipov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Tatyana V. Andreeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Sergey Yu. Filkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Elena V. Gorbacheva
- Institute of Cell Biophysics, Russian Academy of Sciences, Ul. Institutskaya 3, Pushchino, Moscow Region 142290, Russia
| | - Maxim E. Astashev
- Institute of Cell Biophysics, Russian Academy of Sciences, Ul. Institutskaya 3, Pushchino, Moscow Region 142290, Russia
| | - Victor I. Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
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Šribar J, Oberčkal J, Križaj I. Understanding the molecular mechanism underlying the presynaptic toxicity of secreted phospholipases A2: An update. Toxicon 2014; 89:9-16. [DOI: 10.1016/j.toxicon.2014.06.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/19/2014] [Accepted: 06/24/2014] [Indexed: 11/16/2022]
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Two acidic, anticoagulant PLA2 isoenzymes purified from the venom of monocled cobra Naja kaouthia exhibit different potency to inhibit thrombin and factor Xa via phospholipids independent, non-enzymatic mechanism. PLoS One 2014; 9:e101334. [PMID: 25118676 PMCID: PMC4131862 DOI: 10.1371/journal.pone.0101334] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 06/05/2014] [Indexed: 11/20/2022] Open
Abstract
Background The monocled cobra (Naja kaouthia) is responsible for snakebite fatality in Indian subcontinent and in south-western China. Phospholipase A2 (PLA2; EC 3.1.1.4) is one of the toxic components of snake venom. The present study explores the mechanism and rationale(s) for the differences in anticoagulant potency of two acidic PLA2 isoenzymes, Nk-PLA2α (13463.91 Da) and Nk-PLA2β (13282.38 Da) purified from the venom of N. kaouthia. Principal Findings By LC-MS/MS analysis, these PLA2s showed highest similarity (23.5% sequence coverage) with PLA2 III isolated from monocled cobra venom. The catalytic activity of Nk-PLA2β exceeds that of Nk-PLA2α. Heparin differentially regulated the catalytic and anticoagulant activities of these Nk-PLA2 isoenzymes. The anticoagulant potency of Nk-PLA2α was comparable to commercial anticoagulants warfarin, and heparin/antithrombin-III albeit Nk-PLA2β demonstrated highest anticoagulant activity. The anticoagulant action of these PLA2s was partially contributed by a small but specific hydrolysis of plasma phospholipids. The strong anticoagulant effect of Nk-PLA2α and Nk-PLA2β was achieved via preferential, non-enzymatic inhibition of FXa (Ki = 43 nM) and thrombin (Ki = 8.3 nM), respectively. Kinetics study suggests that the Nk-PLA2 isoenzymes inhibit their “pharmacological target(s)” by uncompetitive mechanism without the requirement of phospholipids/Ca2+. The anticoagulant potency of Nk-PLA2β which is higher than that of Nk-PLA2α is corroborated by its superior catalytic activity, its higher capacity for binding to phosphatidylcholine, and its greater strength of thrombin inhibition. These PLA2 isoenzymes thus have evolved to affect haemostasis by different mechanisms. The Nk-PLA2β partially inhibited the thrombin-induced aggregation of mammalian platelets suggesting its therapeutic application in the prevention of unwanted clot formation. Conclusion/Significance In order to develop peptide-based superior anticoagulant therapeutics, future application of Nk-PLA2α and Nk-PLA2β for the treatment and/or prevention of cardiovascular disorders are proposed.
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de Carvalho ND, Garcia RC, Ferreira AK, Batista DR, Cassola AC, Maria D, Lebrun I, Carneiro SM, Afeche SC, Marcourakis T, Sandoval MRL. Neurotoxicity of coral snake phospholipases A2 in cultured rat hippocampal neurons. Brain Res 2014; 1552:1-16. [PMID: 24480475 DOI: 10.1016/j.brainres.2014.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 01/08/2014] [Accepted: 01/09/2014] [Indexed: 12/29/2022]
Abstract
The neurotoxicity of two secreted Phospholipases A2 from Brazilian coral snake venom in rat primary hippocampal cell culture was investigated. Following exposure to Mlx-8 or Mlx-9 toxins, an increase in free cytosolic Ca(2+) and a reduction in mitochondrial transmembrane potential (ΔΨm) became evident and occurred prior to the morphological changes and cytotoxicity. Exposure of hippocampal neurons to Mlx-8 or Mlx-9 caused a decrease in the cell viability as assessed by MTT and LDH assays. Inspection using fluorescent images and ultrastructural analysis by scanning and transmission electron microscopy showed that multiphase injury is characterized by overlapping cell death phenotypes. Shrinkage, membrane blebbing, chromatin condensation, nucleosomal DNA fragmentation and the formation of apoptotic bodies were observed. The most striking alteration observed in the electron microscopy was the fragmentation and rarefaction of the neuron processes network. Degenerated terminal synapses, cell debris and apoptotic bodies were observed among the fragmented fibers. Numerous large vacuoles as well as swollen mitochondria and dilated Golgi were noted. Necrotic signs such as a large amount of cellular debris and membrane fragmentation were observed mainly when the cells were exposed to highest concentration of the PLA2-neurotoxins. PLA2s exposed cultures showed cytoplasmic vacuoles filled with cell debris, clusters of mitochondria presented mitophagy-like structures that are in accordance to patterns of programmed cell death by autophagy. Finally, we demonstrated that the sPLA2s, Mlx-8 and Mlx-9, isolated from the Micrurus lemniscatus snake venom induce a hybrid cell death with apoptotic, autophagic and necrotic features. Furthermore, this study suggests that the augment in free cytosolic Ca(2+) and mitochondrial dysfunction are involved in the neurotoxicity of Elapid coral snake venom sPLA2s.
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Affiliation(s)
| | - Raphael CaioTamborelli Garcia
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP 05508 000, Brazil
| | - Adilson Kleber Ferreira
- Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, SP 05503 900, Brazil
| | - Daniel Rodrigo Batista
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Antonio Carlos Cassola
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Durvanei Maria
- Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, SP 05503 900, Brazil
| | - Ivo Lebrun
- Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, SP 05503 900, Brazil
| | | | - Solange Castro Afeche
- Laboratory of Pharmacology, Butantan Institute, Av. Dr. Vital Brasil 1500, São Paulo, SP 05503 900, Brazil
| | - Tania Marcourakis
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP 05508 000, Brazil
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Ee SM, Lo YL, Shui G, Wenk MR, Shin EJ, Kim HC, Ong WY. Distribution of secretory phospholipase A2 XIIA in the brain and its role in lipid metabolism and cognition. Mol Neurobiol 2014; 50:60-75. [PMID: 24464264 DOI: 10.1007/s12035-014-8635-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/02/2014] [Indexed: 01/03/2023]
Abstract
Phospholipases A(2) (PLA(2)) catalyze the hydrolysis of membrane phospholipids to produce free fatty acids and lysophospholipids, which have important functions in cell signaling. The present study elucidated differential expression of PLA(2) isoforms in the rat cortex by quantitative reverse transcription PCR and demonstrated that sPLA(2)-XIIA had greater messenger RNA expression than iPLA(2)-VI or cPLA(2)-IVA in different brain regions, or compared to other sPLA(2) isoforms in the prefrontal cortex (PFC) and hippocampus. Western blots identified a 24-kDa band in different regions of the adult brain, and high levels of sPLA(2)-XIIA protein expression were detected in the PFC, striatum, and thalamus. Electron microscopy showed that sPLA(2)-XIIA is present in axon terminals and dendrites. Injection of antisense oligonucleotide to sPLA(2)-XIIA in the PFC and lipidomic analysis showed increase in phospholipid but decrease in lysophospholipid species consistent with decreased catalytic activity of the enzyme, changes in arachidonic acid release, and alterations in sphingolipids. sPLA(2)-XIIA knockdown also resulted in shorter latency timings in the passive avoidance test, and higher number of errors in the attention set-shifting task, indicating deficits in working memory and attention. Together, the results show an important role of sPLA(2)-XIIA in lipid metabolism, prefrontal cortical function, and cognition.
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Affiliation(s)
- Sze-Min Ee
- Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore
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Ostrowski M, Žnidaršič PP, Raynal B, Saul F, Faure G. Human coagulation factor Xa prevents oligomerization of anti-coagulant phospholipases A2. TOXIN REV 2013. [DOI: 10.3109/15569543.2013.860170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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The effect of temperature on the effects of the phospholipase A₂ neurotoxins β-bungarotoxin and taipoxin at the neuromuscular junction. Toxicon 2013; 70:86-9. [PMID: 23648422 DOI: 10.1016/j.toxicon.2013.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 04/04/2013] [Accepted: 04/16/2013] [Indexed: 11/21/2022]
Abstract
Snake venom neurotoxins with phospholipase A₂ affect the neuromuscular junction with three distinct phases. There is a transient decrease in twitch height, followed by a facilitatory phase and finally a progressive blockade. It has been suggested that the initial phase is a direct consequence of the binding of the toxins to nerve terminals. This study was designed to determine whether the initial phase is present under conditions that would reduce the enzyme activity of the toxins. At 27 °C, β-bungarotoxin and taipoxin exhibited all three phases, i.e. 5-6 min after exposure to the preparation, twitch height was significantly reduced (P < 0.5) to 50 ± 4% and 64 ± 9% of control respectively. This was followed by facilitation and subsequent blockade. However, at 20 °C, neither toxin exhibited the first phase while the second phase, although reduced, clearly occurred and the blocking activity of these toxins always appeared. The data clearly demonstrate that the initial fall is temperature dependent as reducing the temperature from 27 °C to 20 °C blocks the first phase. As the second phase still occurs the toxins must have bound to their target. Therefore, the first phase cannot simply be a toxin binding step.
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Vardjan N, Mattiazzi M, Rowan EG, Križaj I, Petrovič U, Petan T. Neurotoxic phospholipase A2 toxicity model: An insight from mammalian cells. Commun Integr Biol 2013; 6:e23600. [PMID: 23710275 PMCID: PMC3656009 DOI: 10.4161/cib.23600] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/14/2013] [Indexed: 11/26/2022] Open
Abstract
The molecular mechanism of action of presynaptically neurotoxic secreted phospholipases A2 (sPLA2s) has not been fully elucidated. We have recently proposed a model to explain one of the hallmarks of their action – the reduction in endocytosis leading to synaptic vesicle depletion in nerve terminals. Our results speak strongly in favor of a mechanism in which both specific protein-protein interactions and enzymatic activity of the neurotoxic sPLA2 ammodytoxin A (AtxA) are necessary for impairment of clathrin-dependent endocytosis in yeast cells. The reduction of endocytosis was strictly dependent on the enzymatic activity of sPLA2s expressed ectopically in our yeast model cells and was not observed with the catalytically inactive, non-neurotoxic AtxA-homolog, ammodytin L (AtnL). Here we confirm the validity of the model in mammalian cells also, by demonstrating that the enzymatically active mutant of AtnL, shown to inhibit endocytosis in yeast, acts as a presynaptically neurotoxic sPLA2 at the mammalian neuromuscular junction.
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Affiliation(s)
- Nina Vardjan
- Department of Molecular and Biomedical Sciences; Jožef Stefan Institute; Ljubljana, Slovenia
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41
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Duregotti E, Tedesco E, Montecucco C, Rigoni M. Calpains participate in nerve terminal degeneration induced by spider and snake presynaptic neurotoxins. Toxicon 2012; 64:20-8. [PMID: 23266309 DOI: 10.1016/j.toxicon.2012.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 11/13/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022]
Abstract
α-latrotoxin and snake presynaptic phospholipases A2 neurotoxins target the presynaptic membrane of axon terminals of the neuromuscular junction causing paralysis. These neurotoxins display different biochemical activities, but similarly alter the presynaptic membrane permeability causing Ca(2+) overload within the nerve terminals, which in turn induces nerve degeneration. Using different methods, here we show that the calcium-activated proteases calpains are involved in the cytoskeletal rearrangements that we have previously documented in neurons exposed to α-latrotoxin or to snake presynaptic phospholipases A2 neurotoxins. These results indicate that calpains, activated by the massive calcium influx from the extracellular medium, target fundamental components of neuronal cytoskeleton such as spectrin and neurofilaments, whose cleavage is functional to the ensuing nerve terminal fragmentation.
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Affiliation(s)
- Elisa Duregotti
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Italy
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Huancahuire-Vega S, Corrêa DHA, Hollanda LM, Lancellotti M, Ramos CHI, Ponce-Soto LA, Marangoni S. Chemical modifications of PhTX-I myotoxin from Porthidium hyoprora snake venom: effects on structural, enzymatic, and pharmacological properties. BIOMED RESEARCH INTERNATIONAL 2012; 2013:103494. [PMID: 23484072 PMCID: PMC3591178 DOI: 10.1155/2013/103494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/31/2012] [Indexed: 12/03/2022]
Abstract
We recently described the isolation of a basic PLA2 (PhTX-I) from Porthidium hyoprora snake venom. This toxin exhibits high catalytic activity, induces in vivo myotoxicity, moderates footpad edema, and causes in vitro neuromuscular blockade. Here, we describe the chemical modifications of specific amino acid residues (His, Tyr, Lys, and Trp), performed in PhTX-I, to study their effects on the structural, enzymatic, and pharmacological properties of this myotoxin. After chemical treatment, a single His, 4 Tyr, 7 Lys, and one Trp residues were modified. The secondary structure of the protein remained unchanged as measured by circular dichroism; however other results indicated the critical role played by Lys and Tyr residues in myotoxic, neurotoxic activities and mainly in the cytotoxicity displayed by PhTX-I. His residue and therefore catalytic activity of PhTX-I are relevant for edematogenic, neurotoxic, and myotoxic effects, but not for its cytotoxic activity. This dissociation observed between enzymatic activity and some pharmacological effects suggests that other molecular regions distinct from the catalytic site may also play a role in the toxic activities exerted by this myotoxin. Our observations supported the hypothesis that both the catalytic sites as the hypothetical pharmacological sites are relevant to the pharmacological profile of PhTX-I.
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Affiliation(s)
- Salomón Huancahuire-Vega
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Daniel H. A. Corrêa
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Luciana M. Hollanda
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Marcelo Lancellotti
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Carlos H. I. Ramos
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
- National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ, Brazil
| | - Luis Alberto Ponce-Soto
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Sergio Marangoni
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
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Abstract
Venoms and toxins are of significant interest due to their ability to cause a wide range of pathophysiological conditions that can potentially result in death. Despite their wide distribution among plants and animals, the biochemical pathways associated with these pathogenic agents remain largely unexplored. Impoverished and underdeveloped regions appear especially susceptible to increased incidence and severity due to poor socioeconomic conditions and lack of appropriate medical treatment infrastructure. To facilitate better management and treatment of envenomation victims, it is essential that the biochemical mechanisms of their action be elucidated. This review aims to characterize downstream envenomation mechanisms by addressing the major neuro-, cardio-, and hemotoxins as well as ion-channel toxins. Because of their use in folk and traditional medicine, the biochemistry behind venom therapy and possible implications on conventional medicine will also be addressed.
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Utkin YN, Weise C, Kasheverov IE, Andreeva TV, Kryukova EV, Zhmak MN, Starkov VG, Hoang NA, Bertrand D, Ramerstorfer J, Sieghart W, Thompson AJ, Lummis SCR, Tsetlin VI. Azemiopsin from Azemiops feae viper venom, a novel polypeptide ligand of nicotinic acetylcholine receptor. J Biol Chem 2012; 287:27079-27086. [PMID: 22613724 PMCID: PMC3411050 DOI: 10.1074/jbc.m112.363051] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/15/2012] [Indexed: 11/25/2022] Open
Abstract
Azemiopsin, a novel polypeptide, was isolated from the Azemiops feae viper venom by combination of gel filtration and reverse-phase HPLC. Its amino acid sequence (DNWWPKPPHQGPRPPRPRPKP) was determined by means of Edman degradation and mass spectrometry. It consists of 21 residues and, unlike similar venom isolates, does not contain cysteine residues. According to circular dichroism measurements, this peptide adopts a β-structure. Peptide synthesis was used to verify the determined sequence and to prepare peptide in sufficient amounts to study its biological activity. Azemiopsin efficiently competed with α-bungarotoxin for binding to Torpedo nicotinic acetylcholine receptor (nAChR) (IC(50) 0.18 ± 0.03 μm) and with lower efficiency to human α7 nAChR (IC(50) 22 ± 2 μm). It dose-dependently blocked acetylcholine-induced currents in Xenopus oocytes heterologously expressing human muscle-type nAChR and was more potent against the adult form (α1β1εδ) than the fetal form (α1β1γδ), EC(50) being 0.44 ± 0.1 μm and 1.56 ± 0.37 μm, respectively. The peptide had no effect on GABA(A) (α1β3γ2 or α2β3γ2) receptors at a concentration up to 100 μm or on 5-HT(3) receptors at a concentration up to 10 μm. Ala scanning showed that amino acid residues at positions 3-6, 8-11, and 13-14 are essential for binding to Torpedo nAChR. In biological activity azemiopsin resembles waglerin, a disulfide-containing peptide from the Tropidechis wagleri venom, shares with it a homologous C-terminal hexapeptide, but is the first natural toxin that blocks nAChRs and does not possess disulfide bridges.
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Affiliation(s)
- Yuri N Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia.
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45
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Mattiazzi M, Sun Y, Wolinski H, Bavdek A, Petan T, Anderluh G, Kohlwein SD, Drubin DG, Križaj I, Petrovič U. A neurotoxic phospholipase A2 impairs yeast amphiphysin activity and reduces endocytosis. PLoS One 2012; 7:e40931. [PMID: 22844417 PMCID: PMC3402474 DOI: 10.1371/journal.pone.0040931] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 06/15/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Presynaptically neurotoxic phospholipases A(2) inhibit synaptic vesicle recycling through endocytosis. PRINCIPAL FINDINGS Here we provide insight into the action of a presynaptically neurotoxic phospholipase A(2) ammodytoxin A (AtxA) on clathrin-dependent endocytosis in budding yeast. AtxA caused changes in the dynamics of vesicle formation and scission from the plasma membrane in a phospholipase activity dependent manner. Our data, based on synthetic dosage lethality screen and the analysis of the dynamics of sites of endocytosis, indicate that AtxA impairs the activity of amphiphysin. CONCLUSIONS We identified amphiphysin and endocytosis as the target of AtxA intracellular activity. We propose that AtxA reduces endocytosis following a mechanism of action which includes both a specific protein-protein interaction and enzymatic activity, and which is applicable to yeast and mammalian cells. Knowing how neurotoxic phospholipases A(2) work can open new ways to regulate endocytosis.
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Affiliation(s)
- Mojca Mattiazzi
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Yidi Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Andrej Bavdek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Sepp D. Kohlwein
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Uroš Petrovič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
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Sphingomyelinase D in sicariid spider venom is a potent insecticidal toxin. Toxicon 2012; 60:265-71. [PMID: 22561243 DOI: 10.1016/j.toxicon.2012.04.350] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/17/2012] [Accepted: 04/24/2012] [Indexed: 02/06/2023]
Abstract
Spider venoms have evolved over hundreds of millions of years with a primary role of immobilizing prey. Sphingomyelinase D (SMase D) and homologs in the SicTox gene family are the most abundantly expressed toxic protein in venoms of Loxosceles and Sicarius spiders (Sicariidae). While SMase D is well known to cause dermonecrotic lesions in mammals, little work has investigated the bioactivity of this enzyme in its presumed natural role of immobilizing insect prey. We expressed and purified recombinant SMase D from Loxosceles arizonica (Laz-SMase D) and compared its enzymatic and insecticidal activity to that of crude venom. SMase D enzymatic activities of purified protein and crude venom from the same species were indistinguishable. In addition, SMase D and crude venom have comparable and high potency in immobilization assays on crickets. These data indicate that SMase D is a potent insecticidal toxin, the role for which it presumably evolved.
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47
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A recent evaluation of the lethal potencies of ammodytoxins. Toxicon 2012; 59:642-3. [PMID: 22406514 DOI: 10.1016/j.toxicon.2012.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 02/09/2012] [Accepted: 02/21/2012] [Indexed: 11/20/2022]
Abstract
Ammodytoxin A (AtxA) is the most toxic secreted phospholipase A(2) of the three isotoxins with presynaptic neurotoxicity, isolated from the venom of the nose-horned viper (Vipera ammodytes ammodytes), with an LD(50) of 21 μg/kg in mice. The toxic potencies of two other isoforms have been re-evaluated using highly purified recombinant proteins, with their intraperitoneal LD(50)s determined as 960 μg/kg for AtxB and 310 μg/kg for AtxC. AtxB and AtxC differ from AtxA in only three and two amino acid residues, respectively.
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Renjifo C, Smith EN, Hodgson WC, Renjifo JM, Sanchez A, Acosta R, Maldonado JH, Riveros A. Neuromuscular activity of the venoms of the Colombian coral snakes Micrurus dissoleucus and Micrurus mipartitus: an evolutionary perspective. Toxicon 2011; 59:132-42. [PMID: 22108621 DOI: 10.1016/j.toxicon.2011.10.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 10/23/2011] [Accepted: 10/28/2011] [Indexed: 10/15/2022]
Abstract
The venoms of coral snakes (genus Micrurus) are known to induce a broad spectrum of pharmacological activities. While some studies have investigated their potential human effects, little is known about their mechanism of action in terms of the ecological diversity and evolutionary relationships among the group. In the current study we investigated the neuromuscular blockade of the venom of two sister species Micrurus mipartitus and Micrurus dissoleucus, which exhibit divergent ecological characteristics in Colombia, by using the chick biventer cervicis nerve-muscle preparation. We also undertook a phylogenetic analysis of these species and their congeners, in order to provide an evolutionary framework for the American coral snakes. The venom of M. mipartitus caused a concentration-dependant inhibition (3-10 μg/ml) of nerve-mediated twitches and significantly inhibited contractile responses to exogenous ACh (1 mM), but not KCl (40 mM), indicating a postsynaptic mechanism of action. The inhibition of indirect twitches at the lower venom dose (3 μg/ml) showed to be triphasic and the effect was further attenuated when PLA2 was inhibited. M. dissoleucus venom (10-50 μg/ml) failed to produce a complete blockade of nerve-mediated twitches within a 3 h time period and significantly inhibited contractile responses to exogenous ACh (1 mM) and KCl (40 mM), indicating both postsynaptic and myotoxic mechanisms of action. Myotoxic activity was confirmed by morphological studies of the envenomed tissues. Our results demonstrate a hitherto unsuspected diversity of pharmacological actions in closely related species which exhibit divergent ecological characteristics; these results have important implications for both the clinical management of Coral snake envenomings and the design of Micrurus antivenom.
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Affiliation(s)
- Camila Renjifo
- Departamento de Ciencias Fisiológicas, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia.
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Chiou YL, Chen YJ, Lin SR, Chang LS. Phospholipase A2 activity-dependent and -independent fusogenic activity of Naja nigricollis CMS-9 on zwitterionic and anionic phospholipid vesicles. Toxicon 2011; 58:518-26. [DOI: 10.1016/j.toxicon.2011.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/22/2011] [Accepted: 08/23/2011] [Indexed: 10/17/2022]
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50
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Kao PH, Chiou YL, Chen YJ, Lin SR, Chang LS. Guanidination of notexin promotes its phospholipase A(2) activity-independent fusogenicity on vesicles with lipid-supplied negative curvature. Toxicon 2011; 59:47-58. [PMID: 22030836 DOI: 10.1016/j.toxicon.2011.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 09/27/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
Abstract
To address the requirement of phospholipase A(2) (PLA(2)) activity in membrane fusion events and membrane perturbation activity of notexin and guanidinated notexin (Gu-notexin), the present study was conducted. Notexin and Gu-notexin did not show PLA(2) activity after the removal of Ca(2+) with EDTA. Metal-free notexin and Gu-notexin were found to induce membrane leakage and fusion of phospholipid vesicles. Fusogenic activity of native and modified notexin correlated positively with their membrane-damaging activity underlying the deprivation of PLA(2) activity. Compared with Ca(2+)-bound Gu-notexin, fusogenicity of metal-free Gu-notexin was notably increased by incorporation of cholesterol, cholesterol sulfate, phosphatidylethanolamine, α-tocopherol and phosphatidic acid that supplied negative curvature into phospholipid bilayer. The ability of Gu-notexin to induce membrane fusion of vesicles with lipid-supplied negative curvature was higher than that of notexin regardless of the absence or presence of Ca(2+). Consistently, metal-free Gu-notexin markedly induced membrane fusion of red blood cells (RBCs) compared with metal-free notexin, and fusion activity of metal-free Gu-notexin on cholesterol-depleted RBCs notably reduced. Compared with notexin, Gu-notexin highly induced uptake of calcein-loaded phosphatidylcholine (PC)/cholesterol and PC/cholesterol sulfate vesicles by K562 cells in the presence of EDTA. Taken together, our data suggest that notexin and Gu-notexin could induce vesicle leakage and fusion via a PLA(2) activity-independent mechanism, and guanidination promotes PLA(2) activity-independent fusogenicity of notexin on vesicles with lipid-supplied negative curvature.
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Affiliation(s)
- Pei-Hsiu Kao
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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