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Chen M, Lu M, Feng X, Wu M, Luo X, Xiang R, Luo R, Wu H, Liu Z, Wang M, Zhou X. LmNaTx15, a novel scorpion toxin, enhances the activity of Nav channels and induces pain in mice. Toxicon 2023; 236:107331. [PMID: 37918718 DOI: 10.1016/j.toxicon.2023.107331] [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: 09/16/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/04/2023]
Abstract
Polypeptide toxins are major bioactive components found in venomous animals. Many polypeptide toxins can specifically act on targets, such as ion channels and voltage-gated sodium (Nav) channels, in the nervous, muscle, and cardiovascular systems of the recipient to increase defense and predation efficiency. In this study, a novel polypeptide toxin, LmNaTx15, was isolated from the venom of the scorpion Lychas mucronatus, and its activity was analyzed. LmNaTx15 slowed the fast inactivation of Nav1.2, Nav1.3, Nav1.4, Nav1.5, and Nav1.7 and inhibited the peak current of Nav1.5, but it did not affect Nav1.8. In addition, LmNaTx15 altered the voltage-dependent activation and inactivation of these Nav channel subtypes. Furthermore, like site 3 neurotoxins, LmNaTx15 induced pain in mice. These results show a novel scorpion toxin with a modulatory effect on specific Nav channel subtypes and pain induction in mice. Therefore, LmNaTx15 may be a key bioactive component for scorpion defense and predation. Besides, this study provides a basis for analyzing structure-function relationships of the scorpion toxins affecting Nav channel activity.
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Affiliation(s)
- Minzhi Chen
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Minjuan Lu
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Xujun Feng
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Meijing Wu
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Xiaoqing Luo
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Ruiqi Xiang
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Ren Luo
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Hang Wu
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Zhonghua Liu
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Meichi Wang
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China.
| | - Xi Zhou
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China; Institute of Interdisciplinary Studies, Hunan Normal University, Changsha, 410081, China; Peptide and Small Molecule Drug R&D Plateform, Furong Laboratory, Hunan Normal University, Changsha, 410081, Hunan, China.
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2
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Exploration of Ion Channels in the Clitoris: a Review. CURRENT SEXUAL HEALTH REPORTS 2019. [DOI: 10.1007/s11930-019-00206-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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3
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Shenkarev ZO, Shulepko MA, Peigneur S, Myshkin MY, Berkut AA, Vassilevski AA, Tytgat J, Lyukmanova EN, Kirpichnikov MP. Recombinant Production and Structure–Function Study of the Ts1 Toxin from the Brazilian Scorpion Tityus serrulatus. DOKL BIOCHEM BIOPHYS 2019; 484:9-12. [DOI: 10.1134/s1607672919010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Indexed: 11/23/2022]
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4
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Tibery DV, Campos LA, Mourão CBF, Peigneur S, E Carvalho AC, Tytgat J, Schwartz EF. Electrophysiological characterization of Tityus obscurus β toxin 1 (To1) on Na +-channel isoforms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:142-150. [PMID: 30463697 DOI: 10.1016/j.bbamem.2018.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022]
Abstract
To1, previously named Tc49b, is a peptide neurotoxin isolated from venom of the scorpion Tityus obscurus that is responsible for lethal human poisoning cases in the Brazilian Amazonian region. Previously, To1 was shown to be lethal to mice and to change Na+ permeation in cerebellum granular neurons from rat brain. In addition, To1 did not affect Shaker B K+ channels. Based on sequence similarities, To1 was described as a β-toxin. In the present work, To1 was purified from T. obscurus venom and submitted to an electrophysiological characterization in human and invertebrate NaV channels. The analysis of the electrophysiological experiments reveal that To1 enhances the open probability at more negative potentials of human NaV 1.3 and 1.6, of the insect channel BgNaV1 and of arachnid VdNaV1 channel. In addition, To1 reduces the peak of Na+ currents in some of the NaVs tested. These results support the classification of the To1 as a β-toxin. A structure and functional comparison to other β-toxins that share sequence similarity to To1 is also presented.
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Affiliation(s)
- Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil
| | - Leandro Ambrósio Campos
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil
| | - Caroline Barbosa Farias Mourão
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil; Instituto Federal de Educação, Ciência e Tecnologia de Brasília, Campus Ceilândia, Brasília, Distrito Federal, Brazil
| | - Steve Peigneur
- Toxicology and Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven (KU Leuven), Leuven, Belgium
| | - Andréa Cruz E Carvalho
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil
| | - Jan Tytgat
- Toxicology and Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven (KU Leuven), Leuven, Belgium
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil.
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Martin-Eauclaire MF, Bougis PE, de Lima ME. Ts1 from the Brazilian scorpion Tityus serrulatus: A half-century of studies on a multifunctional beta like-toxin. Toxicon 2018; 152:106-120. [PMID: 30059695 DOI: 10.1016/j.toxicon.2018.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/18/2018] [Accepted: 07/24/2018] [Indexed: 12/19/2022]
Abstract
The Tityus serrulatus scorpion species represents a serious human health threat to in Brazil because it is among the animals that produces the most dangerous venoms for mammals in South America. Its venom has provided several highly selective ligands that specifically interact with sodium and potassium channels. During the past decades, several international groups published an increasing amount of data on the isolation and the chemical, pharmacological and immunological characterisation of its main β-toxin, Ts1. In this review, we compiled the best available past and recent knowledge on Ts1. Aside from its intricate purification, the state-of-the-art understanding concerning its pharmacological activities is presented. Its solved three-dimensional structure is shown, as well as the possible surface areas of contact between Ts1 and its diverse voltage-gated Na+ channel targets. Organisations of the gene and the precursor encoding Ts1 are also tackled based on available cDNA clones or on information obtained from polymerase chain reactions of stretches of scorpion DNA. At last, the immunological studies complete with Ts1 to set up an efficient immunotherapy against the Tityus serrulatus venom are summarized.
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Affiliation(s)
| | - Pierre E Bougis
- Aix Marseille Univ, CNRS, LNC, UMR 7291, 13003, Marseille, France.
| | - Maria Elena de Lima
- Laboratório de Venenos e Toxinas Animais, Depto de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil; Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte - IEP/SCBH, 30150-240, Belo Horizonte, MG, Brazil.
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6
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Investigation of Binding Modes and Functional Surface of Scorpion Toxins ANEP to Sodium Channels 1.7. Toxins (Basel) 2017; 9:toxins9120387. [PMID: 29186022 PMCID: PMC5744107 DOI: 10.3390/toxins9120387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/16/2017] [Accepted: 11/18/2017] [Indexed: 11/17/2022] Open
Abstract
The depressant β toxin anti-neuroexcitation peptide (ANEP) from the Chinese scorpion Buthus martensii Karsch has analgesic activity by interacting with receptor site 4 of the voltage-gated sodium channels (VGSCs). Here, with molecular dynamics simulations, we examined the binding modes between ANEP and the site 4 of mice sodium channel 1.7 (mNav1.7), a subtype of VGSCs related to peripheral pain. Homology modeling, molecular mechanics, and molecular dynamics in the biomembrane environment were adopted. The results suggested that ANEP bound to the resting site 4 mainly by amino acid residues in the β2–β3 loop and the ‘NC’ domains, and the activate site 4 mainly by amino acid residues in the hydrophobic domain of N-groove and residues in the ‘pharmacophore’. Effects analysis of 14 mutants in the predicted functional domains of ANEP on mouse twisting models showed that the analgesic activity of mutants L15 and E24 of the ‘pharmacophore’, W36, T37, W38, and T39 forming the loop between the β2- and β3-strands and N8, V12, C60, and K64 in the NC domain increased distinctly after these residues were substituted for Ala, respectively. The binding modes and the active sites predicted were consistent with available mutagenesis data, and which is meaningful to understand the related mechanisms of ANEP for Nav1.7.
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7
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Target-Specificity in Scorpions; Comparing Lethality of Scorpion Venoms across Arthropods and Vertebrates. Toxins (Basel) 2017; 9:toxins9100312. [PMID: 28976932 PMCID: PMC5666359 DOI: 10.3390/toxins9100312] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 09/22/2017] [Accepted: 09/27/2017] [Indexed: 02/07/2023] Open
Abstract
Scorpions use their venom in defensive situations as well as for subduing prey. Since some species of scorpion use their venom more in defensive situations than others, this may have led to selection for differences in effectiveness in defensive situations. Here, we compared the LD50 of the venom of 10 species of scorpions on five different species of target organisms; two insects and three vertebrates. We found little correlation between the target species in the efficacy of the different scorpion venoms. Only the two insects showed a positive correlation, indicating that they responded similarly to the panel of scorpion venoms. We discuss the lack of positive correlation between the vertebrate target species in the light of their evolution and development. When comparing the responses of the target systems to individual scorpion venoms pairwise, we found that closely related scorpion species tend to elicit a similar response pattern across the target species. This was further reflected in a significant phylogenetic signal across the scorpion phylogeny for the LD50 in mice and in zebrafish. We also provide the first mouse LD50 value for Grosphus grandidieri.
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Coelho P, Kaliontzopoulou A, Rasko M, Meijden A. A ‘striking’ relationship: scorpion defensive behaviour and its relation to morphology and performance. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12855] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pedro Coelho
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Antigoni Kaliontzopoulou
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Mykola Rasko
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Arie Meijden
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
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9
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van der Meijden A, Kleinteich T. A biomechanical view on stinger diversity in scorpions. J Anat 2017; 230:497-509. [PMID: 28028798 PMCID: PMC5345679 DOI: 10.1111/joa.12582] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2016] [Indexed: 01/02/2023] Open
Abstract
Scorpions have elongated metasomas that bear a telson, which is used as a stinger for venom injection. There is a remarkable diversity in the use of the stinger among scorpions, comprising defensive behavior, prey subjugation and mating. This diversity could be reflected by the shape of the telson, as different stinging behaviors will result in very different functional demands. Here we explored the diversity of telson shapes in scorpions by providing morphological measurements, such as curvature and tip angle, as well as by testing stingers under load using finite element analysis (FEA). FEA models were loaded with forces scaled to the surface area of the models, to allow comparison of the relative strain energy based on shape alone. Load force angle was rotated to identify the optimal stinging angle based on the lowest strain energy. Aculeus length and mean aculeus height correlated with minimal strain energy. Optimal stinging angle correlated with tip angle, and differed from the tip angle by about 28.4 ± 6.22 °. We found that species that are more venomous have long aculei (stinger barbs) with a larger radius of curvature. FEA models of these longer aculei showed basal stress concentrations, indicating a potential greater risk of basal breakage due to shape alone. Telsons with shorter and thicker aculeus shapes showed stress concentrations at the tip only. Despite these marked differences in shape, we found no difference in the scaled strain energy between groups of species that are more venomous and less venomous groups of species. These results show that scorpion stingers may be biomechanically optimized, and this may indicate different usage of the stinger in different species.
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Affiliation(s)
- Arie van der Meijden
- CIBIO Research Centre in Biodiversity and Genetic ResourcesInBIOUniversidade do PortoVila do CondePortugal
| | - Thomas Kleinteich
- Department of ZoologyFunctional Morphology and BiomechanicsKielGermany
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Housley DM, Housley GD, Liddell MJ, Jennings EA. Scorpion toxin peptide action at the ion channel subunit level. Neuropharmacology 2016; 127:46-78. [PMID: 27729239 DOI: 10.1016/j.neuropharm.2016.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/06/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022]
Abstract
This review categorizes functionally validated actions of defined scorpion toxin (SCTX) neuropeptides across ion channel subclasses, highlighting key trends in this rapidly evolving field. Scorpion envenomation is a common event in many tropical and subtropical countries, with neuropharmacological actions, particularly autonomic nervous system modulation, causing significant mortality. The primary active agents within scorpion venoms are a diverse group of small neuropeptides that elicit specific potent actions across a wide range of ion channel classes. The identification and functional characterisation of these SCTX peptides has tremendous potential for development of novel pharmaceuticals that advance knowledge of ion channels and establish lead compounds for treatment of excitable tissue disorders. This review delineates the unique specificities of 320 individual SCTX peptides that collectively act on 41 ion channel subclasses. Thus the SCTX research field has significant translational implications for pathophysiology spanning neurotransmission, neurohumoral signalling, sensori-motor systems and excitation-contraction coupling. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- David M Housley
- College of Medicine and Dentistry, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia; Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Gary D Housley
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Michael J Liddell
- Centre for Tropical Environmental and Sustainability Science and College of Science & Engineering, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia
| | - Ernest A Jennings
- College of Medicine and Dentistry, Cairns Campus, James Cook University, Cairns, Queensland 4878, Australia; Centre for Biodiscovery and Molecular Development of Therapeutics, James Cook University, Queensland 4878, Australia; Australian Institute of Tropical Health and Medicine, James Cook University, Cairns Campus, QLD, Australia
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11
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Potassium channel blockers from the venom of the Brazilian scorpion Tityus serrulatus (). Toxicon 2016; 119:253-65. [PMID: 27349167 DOI: 10.1016/j.toxicon.2016.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/06/2016] [Accepted: 06/24/2016] [Indexed: 02/05/2023]
Abstract
Potassium (K(+)) channels are trans-membrane proteins, which play a key role in cellular excitability and signal transduction pathways. Scorpion toxins blocking the ion-conducting pore from the external side have been invaluable probes to elucidate the structural, functional, and physio-pathological characteristics of these ion channels. This review will focus on the interaction between K(+) channels and their peptide blockers isolated from the venom of the scorpion Tityus serrulatus, which is considered as the most dangerous scorpion in Brazil, in particular in Minas-Gerais State, where many casualties are described each year. The primary mechanisms of action of these K(+) blockers will be discussed in correlation with their structure, very often non-canonical compared to those of other well known K(+) channels blockers purified from other scorpion venoms. Also, special attention will be brought to the most recent data obtained by proteomic and transcriptomic analyses on Tityus serrulatus venoms and venom glands.
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12
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Panditrao MM, Panditrao MM, Sunilkumar V, Panditrao AM. Effect of previous scorpion bite(s) on the action of intrathecal bupivacaine: A case control study. Indian J Anaesth 2013; 57:236-40. [PMID: 23983280 PMCID: PMC3748676 DOI: 10.4103/0019-5049.115593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Background: During the routine practice in the institution, it was observed that there were persistent incidents of inadequate/failed spinal anaesthesia in patients with a history of single or multiple scorpion bite/s. To test any possible correlation between scorpion bite and the altered response to spinal anaesthesia, a case control study was conducted involving patients with a history of scorpion bite/s and without such a history. Methods: Randomly selected 70 (n=70) patients of either sex and age range of 18-80 years, were divided into two equal groups, giving past history of one or multiple scorpion bites and giving no such a history. The anaesthetic management was identical inclusive of subarachnoid block with 3.5 ml. 0.5% bupivacaine heavy. The onsets of sensory, motor and peaks of sensory and motor blocks were observed with the pin-prick method and Bromage scale. After waiting for 20 min, if the block was inadequate, then balanced general anaesthesia was administered. The analysis of the data and application of various statistical tests was carried out using Chi-square test, percentages, independent sample t-test and paired t-test. Results: Demographically both groups were comparable. In scorpion bite group, the time of onsets of both sensory and motor blocks and time for the peak of sensory and motor blocks were significantly prolonged, 4 patients had failed/inadequate sensory block and 5 patients had failed/inadequate motor block while all the patients in non-bite group had adequate intra-operative block. Conclusion: We conclude that there appears to be a direct correlation between the histories of old, single or multiple scorpion bites and development of resistance to effect of local anaesthetics administered intra-thecally.
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Affiliation(s)
- Mridul M Panditrao
- Department of Anaesthesiology and Intensive Care, Padmashree Dr. Vithalrao Vikhe Patil Foundation's Medical College and Hospital, Vilad Ghat, Ahmednagar, Maharashtra, India
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13
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Interacting selection diversifies warning signals in a polytypic frog: an examination with the strawberry poison frog. Evol Ecol 2013. [DOI: 10.1007/s10682-013-9648-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Cologna CT, Peigneur S, Rustiguel JK, Nonato MC, Tytgat J, Arantes EC. Investigation of the relationship between the structure and function of Ts2, a neurotoxin from Tityus serrulatus venom. FEBS J 2012; 279:1495-504. [PMID: 22356164 DOI: 10.1111/j.1742-4658.2012.08545.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scorpion toxins targeting voltage-gated sodium (Na(V)) channels are peptides that comprise 60-76 amino acid residues cross-linked by four disulfide bridges. These toxins can be divided in two groups (α and β toxins), according to their binding properties and mode of action. The scorpion α-toxin Ts2, previously described as a β-toxin, was purified from the venom of Tityus serrulatus, the most dangerous Brazilian scorpion. In this study, seven mammalian Na(V) channel isoforms (rNa(V)1.2, rNa(V)1.3, rNa(V)1.4, hNa(V)1.5, mNa(V)1.6, rNa(V)1.7 and rNa(V)1.8) and one insect Na(V) channel isoform (DmNa(V)1) were used to investigate the subtype specificity and selectivity of Ts2. The electrophysiology assays showed that Ts2 inhibits rapid inactivation of Na(V)1.2, Na(V)1.3, Na(V)1.5, Na(V)1.6 and Na(V)1.7, but does not affect Na(V)1.4, Na(V)1.8 or DmNa(V)1. Interestingly, Ts2 significantly shifts the voltage dependence of activation of Na(V)1.3 channels. The 3D structure of this toxin was modeled based on the high sequence identity (72%) shared with Ts1, another T. serrulatus toxin. The overall fold of the Ts2 model consists of three β-strands and one α-helix, and is arranged in a triangular shape forming a cysteine-stabilized α-helix/β-sheet (CSαβ) motif.
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Affiliation(s)
- Camila T Cologna
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Maan ME, Cummings ME. Poison Frog Colors Are Honest Signals of Toxicity, Particularly for Bird Predators. Am Nat 2012; 179:E1-14. [DOI: 10.1086/663197] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abbas N, Rosso JP, Céard B, Belghazi M, Lebrun R, Bougis PE, Martin-Eauclaire MF. Characterization of three "Birtoxin-like" toxins from the Androctonus amoreuxi scorpion venom. Peptides 2011; 32:911-9. [PMID: 21335045 DOI: 10.1016/j.peptides.2011.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 12/19/2022]
Abstract
The venom of the North African scorpion Androctonus amoreuxi (Aam) was analyzed using a combination of gel filtration, C18 reverse phase HPLC together with mass spectrometry analysis and bioassays. Three novel Birtoxin-like (BTX-L) peptides of 58 amino acid residues comprising three disulfide bridges were isolated and chemically characterized. One peptide, AamBTX-L3, induced serious toxic symptoms in mice and was lethal at nanogram quantities using intracerebroventricular injection. The three BTX-L peptides were tested in competition experiments on rat brain synaptosomes against the (125)I-labeled "classical" α- and β-toxins of reference, as well as with the (125)I-KTX, a voltage-gated potassium channel blocker. Only AamBTX-L3 was able to prevent the equilibrium binding of the β-toxin (125)I-Css IV to its receptor site 4 with a IC(50) value of 189 nM. Even if previous electrophysiological data allowed the classification of other BTX-L peptides among the β-type toxins, this report clearly shows that AamBTX-L3 is pharmacologically a β-toxin, which recognizes the voltage-gated Na(+) (Na(v)) channels from central mammalian neurons. In order to uncover the residues functionally essential for interaction between the AamBTX-L3 with the putative receptor site of (125)I-Css IV on Na(v)1.2, molecular models of the three novel Aam BTX-L molecules were made and their surfaces were compared to the already described Css IV biologically interactive surfaces. A hypothesis is given that in BTX-L3, three residues found in the α-helix play a key role during target binding.
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Affiliation(s)
- Najwa Abbas
- CNRS UMR6231, CRN2M, Université de la Méditerranée, Faculté de Médecine secteur Nord, CS80011, Bd Pierre Dramard, F-13344 Marseille Cedex 15, France
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Martin-Eauclaire MF, Abbas N, Sauze N, Mercier L, Berge-Lefranc JL, Condo J, Bougis PE, Guieu R. Involvement of endogenous opioid system in scorpion toxin-induced antinociception in mice. Neurosci Lett 2010; 482:45-50. [DOI: 10.1016/j.neulet.2010.06.090] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/11/2010] [Accepted: 06/29/2010] [Indexed: 10/19/2022]
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Isolation and characterization of two novel scorpion toxins: The alpha-toxin-like CeII8, specific for Na(v)1.7 channels and the classical anti-mammalian CeII9, specific for Na(v)1.4 channels. Toxicon 2010; 56:613-23. [PMID: 20600228 DOI: 10.1016/j.toxicon.2010.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 06/08/2010] [Accepted: 06/11/2010] [Indexed: 11/23/2022]
Abstract
Scorpion beta-toxins represent a particular pharmacological group of voltage-gated sodium channel (VGSC) neurotoxins. They typically shift the voltage dependence of activation to more hyperpolarizing potentials and reduce the peak current amplitude by binding to receptor-site 4. Here, we report the purification and functional characterization of the first voltage-gated sodium channel toxins, CeII8 and CeII9, isolated from the scorpion Centruroides elegans (Thorell, 1876), which is responsible for deadly cases of intoxication in Mexico. The soluble venom was fractionated by gel filtration and ion-exchange chromatography, followed by reversed-phase HPLC. The toxins CeII8 and CeII9 were further purified and both their amino acid sequence and molecular weight were determined. Both toxins were electrophysiologically characterized on four mammalian VGSCs (rNa(v)1.2, rNa(v)1.4, hNa(v)1.5 and rNa(v)1.7) expressed heterologously in Xenopus laevis oocytes, using the two-electrode voltage-clamp technique. Although CeII8 has the highest sequence similarity with scorpion alpha-toxins, inhibiting the inactivation of VGSCs, 300 nM toxin had a clear beta-toxin effect and was selective towards Na(v)1.7, involved in short-term and inflammatory pain. To the best of our knowledge, CeII8 is the first beta-toxin active on Na(v)1.7. CeII9, a typical anti-mammalian beta-toxin, selectively modulated Na(v)1.4 at a concentration of 700 nM and was, in contrast to CeII8, found to be lethal to mice. Interestingly, both toxins, despite their differences in amino acid sequence, only altered the biophysical properties of a fraction of the expressed sodium channels. Since these effects have also been reported for the beta-toxin CssIV, the bioactive surfaces of the toxins have been compared to each other.
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Billen B, Vassilevski A, Nikolsky A, Debaveye S, Tytgat J, Grishin E. Unique bell-shaped voltage-dependent modulation of Na+ channel gating by novel insect-selective toxins from the spider Agelena orientalis. J Biol Chem 2010; 285:18545-54. [PMID: 20385552 DOI: 10.1074/jbc.m110.125211] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spider venoms provide a highly valuable source of peptide toxins that act on a wide diversity of membrane-bound receptors and ion channels. In this work, we report isolation, biochemical analysis, and pharmacological characterization of a novel family of spider peptide toxins, designated beta/delta-agatoxins. These toxins consist of 36-38 amino acid residues and originate from the venom of the agelenid funnel-web spider Agelena orientalis. The presented toxins show considerable amino acid sequence similarity to other known toxins such as mu-agatoxins, curtatoxins, and delta-palutoxins-IT from the related spiders Agelenopsis aperta, Hololena curta, and Paracoelotes luctuosus. beta/delta-Agatoxins modulate the insect Na(V) channel (DmNa(V)1/tipE) in a unique manner, with both the activation and inactivation processes being affected. The voltage dependence of activation is shifted toward more hyperpolarized potentials (analogous to site 4 toxins) and a non-inactivating persistent Na(+) current is induced (site 3-like action). Interestingly, both effects take place in a voltage-dependent manner, producing a bell-shaped curve between -80 and 0 mV, and they are absent in mammalian Na(V) channels. To the best of our knowledge, this is the first detailed report of peptide toxins with such a peculiar pharmacological behavior, clearly indicating that traditional classification of toxins according to their binding sites may not be as exclusive as previously assumed.
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Affiliation(s)
- Bert Billen
- Laboratory of Toxicology, University of Leuven, KU Leuven, Campus Gasthuisberg O&N2, Herestraat 49, PO Box 922, B-3000 Leuven, Belgium
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Petricevich VL. Scorpion venom and the inflammatory response. Mediators Inflamm 2010; 2010:903295. [PMID: 20300540 PMCID: PMC2838227 DOI: 10.1155/2010/903295] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 01/04/2010] [Indexed: 02/06/2023] Open
Abstract
Scorpion venoms consist of a complex of several toxins that exhibit a wide range of biological properties and actions, as well as chemical compositions, toxicity, and pharmacokinetic and pharmacodynamic characteristics. These venoms are associated with high morbility and mortality, especially among children. Victims of envenoming by a scorpion suffer a variety of pathologies, involving mainly both sympathetic and parasympathetic stimulation as well as central manifestations such as irritability, hyperthermia, vomiting, profuse salivation, tremor, and convulsion. The clinical signs and symptoms observed in humans and experimental animals are related with an excessive systemic host inflammatory response to stings and stings, respectively. Although the pathophysiology of envenomation is complex and not yet fully understood, venom and immune responses are known to trigger the release of inflammatory mediators that are largely mediated by cytokines. In models of severe systemic inflammation produced by injection of high doses of venom or venoms products, the increase in production of proinflammatory cytokines significantly contributes to immunological imbalance, multiple organ dysfunction and death. The cytokines initiate a cascade of events that lead to illness behaviors such as fever, anorexia, and also physiological events in the host such as activation of vasodilatation, hypotension, and increased of vessel permeability.
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Affiliation(s)
- Vera L Petricevich
- Laboratorio de Inflamación y Toxicología, Facultad de Medicina de la Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Cuernavaca, Morelos 62209, Mexico.
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Billen B, Vassilevski A, Nikolsky A, Tytgat J, Grishin E. Two novel sodium channel inhibitors from Heriaeus melloteei spider venom differentially interacting with mammalian channel's isoforms. Toxicon 2008; 52:309-17. [DOI: 10.1016/j.toxicon.2008.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 05/20/2008] [Accepted: 05/30/2008] [Indexed: 12/19/2022]
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Tian C, Yuan Y, Zhu S. Positively selected sites of scorpion depressant toxins: possible roles in toxin functional divergence. Toxicon 2007; 51:555-62. [PMID: 18177911 DOI: 10.1016/j.toxicon.2007.11.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 11/07/2007] [Accepted: 11/14/2007] [Indexed: 02/04/2023]
Abstract
Scorpion depressant toxins represent a distinct pharmacological group of sodium channel neurotoxins, identified by their preferential ability in induction of depressant and flaccid paralysis of insects. However, recent observations that some members in this group exhibit anti-mammal activity raise an interesting evolutionary question of whether it is a consequence of adaptive evolution to the early radiation of mammals on earth. By employing the maximum likelihood method, we provided convincing statistical evidence in favor of positive selection driving the evolution of the depressant toxins, and found that two of three positively selected sites are located on the functional surface of the toxins. A complex model of the scorpion depressant toxin LqhIT2 binding to insect sodium channel alpha-subunit (DmNav1) was constructed by structural bioinformatics approaches which highlights a possible direct interaction between these two sites and insect sodium channels. Our work presented here thus suggests that accelerated substitutions in these site residues could offer an evolutionary advantage for these toxins to adapt different channels from diverse origins.
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Affiliation(s)
- Caihuan Tian
- Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
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Cohen L, Ilan N, Gur M, Stühmer W, Gordon D, Gurevitz M. Design of a specific activator for skeletal muscle sodium channels uncovers channel architecture. J Biol Chem 2007; 282:29424-30. [PMID: 17686768 DOI: 10.1074/jbc.m704651200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gating modifiers of voltage-gated sodium channels (Na(v)s) are important tools in neuroscience research and may have therapeutic potential in medicinal disorders. Analysis of the bioactive surface of the scorpion beta-toxin Css4 (from Centruroides suffusus suffusus) toward rat brain (rNa(v)1.2a) and skeletal muscle (rNa(v)1.4) channels using binding studies revealed commonality but also substantial differences, which were used to design a specific activator, Css4(F14A/E15A/E28R), of rNa(v)1.4 expressed in Xenopus oocytes. The therapeutic potential of Css4(F14A/E15A/E28R) was tested using an rNa(v)1.4 mutant carrying the same mutation present in the genetic disorder hypokalemic periodic paralysis. The activator restored the impaired gating properties of the mutant channel expressed in oocytes, thus offering a tentative new means for treatment of neuromuscular disorders with reduced muscle excitability. Mutant double cycle analysis employing toxin residues involved in the construction of Css4(F14A/E15A/E28R) and residues whose equivalents in the rat brain channel rNa(v)1.2a were shown to affect Css4 binding revealed significant coupling energy (>1.3 kcal/mol) between F14A and E592A at Domain-2/voltage sensor segments 1-2 (D2/S1-S2), R27Q and E1251N at D3/SS2-S6, and E28R with both E650A at D2/S3-S4 and E1251N at D3/SS2-S6. These results show that despite the differences in interactions with the rat brain and skeletal muscle Na(v)s, Css4 recognizes a similar region on both channel subtypes. Moreover, our data indicate that the S3-S4 loop of the voltage sensor module in Domain-2 is in very close proximity to the SS2-S6 segment of the pore module of Domain-3 in rNa(v)1.4. This is the first experimental evidence that the inter-domain spatial organization of mammalian Na(v)s resembles that of voltage-gated potassium channels.
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Affiliation(s)
- Lior Cohen
- Department of Plant Sciences, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, 69978 Tel-Aviv, Israel
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Tan M, Zhu MM, Liu Y, Cheng HW, Ji YH. Effects of BmK AS on Nav1.2 expressed in Xenopus laevis oocytes. Cell Biol Toxicol 2007; 24:143-9. [PMID: 17674132 DOI: 10.1007/s10565-007-9023-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 07/11/2007] [Indexed: 11/30/2022]
Abstract
In the present study, the pharmacological effects of BmK AS, a beta-like scorpion toxin on rNav1.2 alpha-subunit expressed in Xenopus laevis oocytes were investigated using a two-electrode voltage-clamp recording. It was found that the voltage dependence of rNav1.2 inactivation was significantly shifted towards positive membrane potential by 500 nM BmK AS, whereas the activation curves of rNav1.2 were unruffled at the same dosage. The inactivation curves of both slow and fast inactivation currents were positively moved about 12.8 and 9.7 mV, respectively. In addition, the persistent currents of rNav1.2 were invariable. The effects of BmK AS on the rNav1.2 inactivation were opposite to the previous results found in the peripheral sensory neurons. The results suggested that Nav1.2 might be the target of BmK AS in the central nervous system, and BmK AS might have an excitatory effect on the central neuron through enhancing Nav1.2.
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Affiliation(s)
- Miao Tan
- Graduate School of the Chinese Academy of Sciences, Institute of Physiology, Shanghai Institutes for Biological Sciences, Shanghai, People's Republic of China
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de la Vega RCR, Possani LD. Novel paradigms on scorpion toxins that affects the activating mechanism of sodium channels. Toxicon 2007; 49:171-80. [PMID: 17081580 DOI: 10.1016/j.toxicon.2006.09.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Scorpion toxins classified as beta-class are reviewed using a new paradigm. Four distinct sub types are recognized: "classical", "Tsgamma-like", "excitatory" and "depressant"beta-scorpion toxins. Recent experimental data have made possible to identify the interacting interfaces of the Na(+) channel-receptor site 4 with some of these toxins. The voltage-sensor trapping mechanism proposed for the action of these toxic peptides is analyzed in the context of what causes a modification of the activating mechanism of Na(+) channels. A cartoon model is presented with the purpose of summarizing the most current knowledge on the field. Finally, the recent advances on the knowledge of the specific interactions of beta-toxins and different sub types of Na(+) channels are also reviewed.
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Affiliation(s)
- Ricardo C Rodríguez de la Vega
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Av. Universidad 2001, Cuernavaca Morelos 62210, México.
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