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Martin-Eauclaire MF, Marchot P. Obituary - Hervé Paul Marie Antoine ROCHAT 1937-2023. Toxicon 2023; 233:107249. [PMID: 37659118 DOI: 10.1016/j.toxicon.2023.107249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2023]
Affiliation(s)
- Marie-France Martin-Eauclaire
- Lab. "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Centre National de La Recherche Scientifique (CNRS), Aix-Marseille Univ. (AMU), Faculté des Sciences - Campus Luminy, Marseille, France.
| | - Pascale Marchot
- Lab. "Architecture et Fonction des Macromolécules Biologiques" (AFMB), Centre National de La Recherche Scientifique (CNRS), Aix-Marseille Univ. (AMU), Faculté des Sciences - Campus Luminy, Marseille, France.
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Rebbouh F, Martin-Eauclaire MF, Laraba-Djebari F. Chitosan nanoparticles as a delivery platform for neurotoxin II from Androctonus australis hector scorpion venom: Assessment of toxicity and immunogenicity. Acta Trop 2020; 205:105353. [PMID: 31982432 DOI: 10.1016/j.actatropica.2020.105353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 10/25/2022]
Abstract
In recent years, biodegradable polymers based nanoparticles received high interest for the development of vaccine delivery vehicles. In this study, chitosan nanoparticles encapsulating Aah II toxin (AahII-CNPs) isolated from Androctonus australis hector venom, were investigated as vaccine delivery system. Particles obtained by ionotropic gelation were characterized for their size, surface charge, morphology and toxin release profile from Aah II-CNPs. Toxin-nanoparticles interactions were assessed by Fourier Transform Infrared Spectrometry and X-Ray Diffraction. An immunization protocol was designed in mice to investigate anti-toxin immunity and the protective status induced by different Aah II immune formulations. Unloaded chitosan nanoparticles presenting a spherical shape and smooth surface, were characterized by a size of 185 nm, a dispersion index (PDI) of 0.257 and a zeta potential of +34.6 mV. Aah II toxin was successfully entrapped into chitosan nanoparticles as revealed by FTIR and XRD data. Entrapment efficiency (EE) and Loading capacity (LC) were respectively of 96.66 and 33.5%. Aah II-CNPs had a diameter of 208 nm, a PDI of 0.23 and a zeta potential of +30 mV. Encapsulation of Aah II reduced its toxicity and protected mice until 10 LD50. Mice were immunized via a dual prime-boost scheme. Nanoentrapped Aah II immunogen elicited systemic innate and humoral immune responses as well as local spleen parenchyma hyperplasic alterations. Aah II-CNPs immunized mice withstood high lethal doses of native Aah II, one-month post-boost inoculation. This study provided encouraging and promising results for the development of preventive therapies against scorpion envenoming mainly for the populations at-risk.
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Clairfeuille T, Cloake A, Infield DT, Llongueras JP, Arthur CP, Li ZR, Jian Y, Martin-Eauclaire MF, Bougis PE, Ciferri C, Ahern CA, Bosmans F, Hackos DH, Rohou A, Payandeh J. Structural basis of α-scorpion toxin action on Na v channels. Science 2019; 363:science.aav8573. [PMID: 30733386 DOI: 10.1126/science.aav8573] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023]
Abstract
Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling, but its mechanism remains poorly understood. Here we determined the structures of a eukaryotic Nav channel alone and in complex with a lethal α-scorpion toxin, AaH2, by electron microscopy, both at 3.5-angstrom resolution. AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state in which gating charge interactions bridge to the acidic intracellular carboxyl-terminal domain. In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery. Highlighting the polypharmacology of α-scorpion toxins, AaH2 also targets an unanticipated receptor site on VSD1 and a pore glycan adjacent to VSD4. Overall, this work provides key insights into fast inactivation, electromechanical coupling, and pathogenic mutations in Nav channels.
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Affiliation(s)
- Thomas Clairfeuille
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Alexander Cloake
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.,Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - José P Llongueras
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Zhong Rong Li
- Department of Biomolecular Resources, Genentech Inc., South San Francisco, CA, USA
| | - Yuwen Jian
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, LNC, UMR 7291, 13003 Marseille, France
| | - Claudio Ciferri
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium.
| | - David H Hackos
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
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Martin-Eauclaire MF, Adi-Bessalem S, Hammoudi-Triki D, Laraba-Djebari F, Bougis PE. Serotherapy against Voltage-Gated Sodium Channel-Targeting αToxins from Androctonus Scorpion Venom. Toxins (Basel) 2019; 11:toxins11020063. [PMID: 30678116 PMCID: PMC6410273 DOI: 10.3390/toxins11020063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/18/2019] [Accepted: 01/21/2019] [Indexed: 12/12/2022] Open
Abstract
Because of their venom lethality towards mammals, scorpions of the Androctonus genus are considered a critical threat to human health in North Africa. Several decades of exploration have led to a comprehensive inventory of their venom components at chemical, pharmacological, and immunological levels. Typically, these venoms contain selective and high affinity ligands for the voltage-gated sodium (Nav) and potassium (Kv) channels that dictate cellular excitability. In the well-studied Androctonus australis and Androctonus mauretanicus venoms, almost all the lethality in mammals is due to the so-called α-toxins. These peptides commonly delay the fast inactivation process of Nav channels, which leads to increased sodium entry and a subsequent cell membrane depolarization. Markedly, their neutralization by specific antisera has been shown to completely inhibit the venom’s lethal activity, because they are not only the most abundant venom peptide but also the most fatal. However, the structural and antigenic polymorphisms in the α-toxin family pose challenges to the design of efficient serotherapies. In this review, we discuss past and present accomplishments to improve serotherapy against Androctonus scorpion stings.
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Affiliation(s)
| | - Sonia Adi-Bessalem
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Djelila Hammoudi-Triki
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Fatima Laraba-Djebari
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Pierre E Bougis
- Laboratory of Cognitive Neuroscience, CNRS, Aix Marseille Univ, UMR 7291, 13003 Marseille, France.
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Taibi-Djennah Z, Martin-Eauclaire MF, Laraba-Djebari F. Evaluation of neuroprotective effects of insulin on immuno-inflammatory and systemic disorders induced by kaliotoxin, a Kv1.3 channel blocker. Inflamm Res 2018; 67:863-877. [DOI: 10.1007/s00011-018-1177-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/12/2018] [Accepted: 08/01/2018] [Indexed: 12/11/2022] Open
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Emerich BL, De Lima ME, Martin-Eauclaire MF, Bougis PE. Comparative analyses and implications for antivenom serotherapy of four Moroccan scorpion Buthus occitanus venoms: Subspecies tunetanus, paris, malhommei, and mardochei. Toxicon 2017; 149:26-36. [PMID: 28712915 DOI: 10.1016/j.toxicon.2017.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 01/14/2023]
Abstract
Temporary passive immunity such as serotherapy against venoms requires the full knowledge of all venom's components. Here, four venoms from Moroccan common yellow scorpions belonging to Buthus occitanus, subspecies tunetanus, paris, malhommei, and mardochei, all collected in four different restricted areas, were analysed in deep. They were fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) and their molecular masse profile determined by off-line MALDI-TOF mass spectrometry. Characterisation of their main components was achieved by enzyme-linked immunosorbent assay (ELISA) using specific antisera against the major lethal scorpion toxins identified so far, i.e. voltage-gated sodium channels (Nav) modulators α- and β-toxins, as well as diverse potassium channel pore blocker toxins. For fractions with identical RP-HPLC retention times, we observe that their relative quantities show large differences. Moreover, identical masses present simultaneously in the four venoms are infrequent. ELISAs show that the majority of the RP-HPLC compounds cross-react with the antiserum against the "α-like" toxin Bot I, which has been previously identified in the Algerian Buthus occitanus tunetanus venom. Moreover, minor fractions were recognised by the antiserum against the highly lethal "classical" α-toxin of reference AaH II from the Androctonus australis venom. As such, our results bring new sights for further improving scorpion venom serotherapy in Morocco.
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Affiliation(s)
- Bruna Luiza Emerich
- Aix Marseille Université, CNRS, CRN2M UMR7286, 13344, Marseille, France; Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo-Horizonte, MG, Brazil
| | - Maria Elena De Lima
- Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo-Horizonte, MG, Brazil
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, CRN2M UMR7286, 13344, Marseille, France.
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Martin-Eauclaire MF, Salvatierra J, Bosmans F, Bougis PE. The scorpion toxin Bot IX is a potent member of the α-like family and has a unique N-terminal sequence extension. FEBS Lett 2016; 590:3221-32. [DOI: 10.1002/1873-3468.12357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 11/08/2022]
Affiliation(s)
| | - Juan Salvatierra
- Department of Physiology; School of Medicine; Johns Hopkins University; Baltimore MD USA
| | - Frank Bosmans
- Department of Physiology; School of Medicine; Johns Hopkins University; Baltimore MD USA
- Solomon H. Snyder Department of Neuroscience; School of Medicine; Johns Hopkins University; Baltimore MD USA
| | - Pierre E. Bougis
- Aix Marseille Université; CNRS; CRN2M; UMR7286; PFRN-CAPM; Marseille France
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Nakib I, Martin-Eauclaire MF, Laraba-Djebari F. Involvement of Cholinergic and Adrenergic Receptors in Pathogenesis and Inflammatory Response Induced by Alpha-Neurotoxin Bot III of Scorpion Venom. Inflammation 2016; 39:1670-80. [PMID: 27395044 DOI: 10.1007/s10753-016-0401-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bot III neurotoxin is the most lethal α neurotoxin purified from Buthus occitanus tunetanus scorpion venom. This toxin binds to the voltage-gated sodium channel of excitable cells and blocks its inactivation, inducing an increased release of neurotransmitters (acetylcholine and catecholamines). This study aims to elucidate the involvement of cholinergic and adrenergic receptors in pathogenesis and inflammatory response triggered by this toxin. Injection of Bot III to animals induces an increase of peroxidase activities, an imbalance of oxidative status, tissue damages in lung parenchyma, and myocardium correlated with metabolic disorders. The pretreatment with nicotine (nicotinic receptor agonist) or atropine (muscarinic receptor antagonist) protected the animals from almost all disorders caused by Bot III toxin, especially the immunological alterations. Bisoprolol administration (selective β1 adrenergic receptor antagonist) was also efficient in the protection of animals, mainly on tissue damage. Propranolol (non-selective adrenergic receptor antagonist) showed less effect. These results suggest that both cholinergic and adrenergic receptors are activated in the cardiopulmonary manifestations induced by Bot III. Indeed, the muscarinic receptor appears to be more involved than the nicotinic one, and the β1 adrenergic receptor seems to dominate the β2 receptor. These results showed also that the activation of nicotinic receptor leads to a significant protection of animals against Bot III toxin effect. These findings supply a supplementary data leading to better understanding of the mechanism triggered by scorpionic neurotoxins and suggest the use of drugs targeting these receptors, especially the nicotinic one in order to counteract the inflammatory response observed in scorpion envenomation.
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Affiliation(s)
- Imene Nakib
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP 32, El-Alia Bab Ezzouar, 16111, Algiers, Algeria
| | - Marie-France Martin-Eauclaire
- Aix-Marseille University, CNRS UMR7290 CRN2M, IFR Jean-Roche, Université de la Méditerranée, Faculté de Médecine Nord, Bd Pierre Dramard, 13916, Marseille, Cedex 20, France
| | - Fatima Laraba-Djebari
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP 32, El-Alia Bab Ezzouar, 16111, Algiers, Algeria.
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Ladjel-Mendil A, Martin-Eauclaire MF, Laraba-Djebari F. Neuro-Modulation of Immuno-Endocrine Response Induced by Kaliotoxin of Androctonus Scorpion Venom. J Biochem Mol Toxicol 2016; 30:580-587. [PMID: 27271987 DOI: 10.1002/jbt.21824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/18/2016] [Accepted: 05/23/2016] [Indexed: 12/16/2022]
Abstract
Kaliotoxin (KTX), a specific blocker of potassium channels, exerts various toxic effects due to its action on the central nervous system. Its use in experimental model could help the understanding of the cellular and molecular mechanisms involved in the neuropathological processes related to potassium channel dysfunctions. In this study, the ability of KTX to stimulate neuro-immuno-endocrine axis was investigated. As results, the intracerebroventricular injection of KTX leads to severe structural-functional alterations of both hypothalamus and thyroid. These alterations were characterized by a massive release of hormones' markers of thyroid function associated with damaged tissue which was infiltrated by inflammatory cell and an imbalanced redox status. Taken together, these data highlight that KTX is able to modulate the neuro-endocrine response after binding to its targets leading to the hypothalamus and the thyroid stimulation, probably by inflammatory response activation and the installation of oxidative stress in these organs.
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Affiliation(s)
- Amina Ladjel-Mendil
- USTHB, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
| | - Marie-France Martin-Eauclaire
- CNRS UMR 7286 CRN2M, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord, Aix-Marseille University, Marseille, France
| | - Fatima Laraba-Djebari
- USTHB, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
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Sifi N, Martin-Eauclaire MF, Laraba-Djebari F. K(+) channel blocker-induced neuroinflammatory response and neurological disorders: immunomodulatory effects of astaxanthin. Inflamm Res 2016; 65:623-34. [PMID: 27052008 DOI: 10.1007/s00011-016-0945-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 03/18/2016] [Accepted: 03/30/2016] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Channelopathies due to the brain ion channel dysfunction is considered to be an important mechanism involved in various neurodegenerative diseases. In this study, we evaluated the ability of kaliotoxin (KTX) as K(+) channel blocker to induce neuro-inflammatory response and neurodegenerative alteration. We also investigate the effects of astaxanthin (ATX) against KTX disorders. MATERIAL AND TREATMENT NMRI mice were injected with KTX (1 pg/kg, by i.c.v route) with or without pretreatment using ATX (80 mg/kg, o.p route). RESULTS Results showed that KTX was detected in cerebral cortex area due to its binding to the specific receptors (immunofluorescence analysis). It induced an activation of inflammatory cascade characterized by an increase of IL-6, TNFα, NO, MDA levels and NF-κB expression associated to a decrease of GSH level. The neuroinflammatory response is accompanied with cerebral alterations and blood-brain barrier (BBB) disruption. The use of ATX prior to the KTX exerts a preventive effect not only on the neuroinflammation but also on altered tissues and the BBB disruption. CONCLUSIONS Kaliotoxin is able to induce neurological disorders by blocking the K(+) ion channel, and ATX suppresses this alterations with down regulation of IL-6, TNF-α and NF-κB expression in the brain.
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Affiliation(s)
- Nesrine Sifi
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar, 16111, Algiers, Algeria
| | | | - Fatima Laraba-Djebari
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar, 16111, Algiers, Algeria.
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Martin-Eauclaire MF, Ferracci G, Bosmans F, Bougis PE. A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif. ACTA ACUST UNITED AC 2015; 145:155-62. [PMID: 25624450 PMCID: PMC4306711 DOI: 10.1085/jgp.201411268] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The isolated Nav channel domain IV paddle motif remains susceptible to toxins that inhibit fast inactivation. Animal toxins that inhibit voltage-gated sodium (Nav) channel fast inactivation can do so through an interaction with the S3b–S4 helix-turn-helix region, or paddle motif, located in the domain IV voltage sensor. Here, we used surface plasmon resonance (SPR), an optical approach that uses polarized light to measure the refractive index near a sensor surface to which a molecule of interest is attached, to analyze interactions between the isolated domain IV paddle and Nav channel–selective α-scorpion toxins. Our SPR analyses showed that the domain IV paddle can be removed from the Nav channel and immobilized on sensor chips, and suggest that the isolated motif remains susceptible to animal toxins that target the domain IV voltage sensor. As such, our results uncover the inherent pharmacological sensitivities of the isolated domain IV paddle motif, which may be exploited to develop a label-free SPR approach for discovering ligands that target this region.
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Affiliation(s)
- Marie-France Martin-Eauclaire
- Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseillle, Unité Mixte de Recherche 7286, Plates-Formes de Recherche en Neurosciences-Centre d'Analyse Protéomique de Marseille, Aix Marseille Université, 13344 Marseille, France
| | - Géraldine Ferracci
- Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseillle, Unité Mixte de Recherche 7286, Plates-Formes de Recherche en Neurosciences-Centre d'Analyse Protéomique de Marseille, Aix Marseille Université, 13344 Marseille, France
| | - Frank Bosmans
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205 Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Pierre E Bougis
- Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseillle, Unité Mixte de Recherche 7286, Plates-Formes de Recherche en Neurosciences-Centre d'Analyse Protéomique de Marseille, Aix Marseille Université, 13344 Marseille, France
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Medjadba W, Martin-Eauclaire MF, Laraba-Djebari F. Involvement of Kallikrein-Kinin System on Cardiopulmonary Alterations and Inflammatory Response Induced by Purified Aah I Toxin from Scorpion Venom. Inflammation 2015; 39:290-302. [PMID: 26361946 DOI: 10.1007/s10753-015-0249-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bradykinins are released from kininogen by kallikrein. They increase capillary lung permeability after their binding to β1 and especially β2 receptors before being metabolized by kininase enzyme. This study was performed to evaluate cardiopulmonary damages and inflammatory response on injected rats with Aah I toxin of scorpion venom and the involvement of Kallikrein-Kinin system in this pathogenesis. Obtained results revealed that Aah I toxin induces inflammatory cell infiltration accompanied by cellular peroxidase activities, a release of cytokine levels, pulmonary and myocardial damage, with altered metabolic activities and imbalanced redox status. Administration of aprotinin (bradykinin inhibitor) and especially icatibant (bradykinin β2 receptor antagonist) seemed to be able to protect animals against the toxicity of Aah I; nevertheless, the use of captopril (kininase II inhibitor) reduced partially some cardiac disorders. These findings indicate that the kallikrein-kinin system may contribute to the physiopathological effect and lung edema formation induced by toxin, which suggests a potential use of drugs with significant anti-kinin properties.
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Affiliation(s)
- Wafa Medjadba
- USTHB, Faculty of Biological Sciences, Laboratory Cellular and Molecular Biology, Department Cellular and Molecular Biology, BP32, EL Alia, Bab Ezzouar, 16111, Algiers, Algeria
| | - Marie-France Martin-Eauclaire
- Aix-Marseille University, CNRS UMR 7286 CRN2M, IFR Jean-Roche, Faculté de Médecine Nord, Bd Pierre Dramard, 13916, Marseille, Cedex 20, France
| | - Fatima Laraba-Djebari
- USTHB, Faculty of Biological Sciences, Laboratory Cellular and Molecular Biology, Department Cellular and Molecular Biology, BP32, EL Alia, Bab Ezzouar, 16111, Algiers, Algeria.
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Bekkari N, Martin-Eauclaire MF, Laraba-Djebari F. Complement system and immunological mediators: Their involvements in the induced inflammatory process by Androctonus australis hector venom and its toxic components. ACTA ACUST UNITED AC 2015; 67:389-97. [DOI: 10.1016/j.etp.2015.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/12/2015] [Accepted: 04/02/2015] [Indexed: 01/01/2023]
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Bougis PE, Martin-Eauclaire MF. Shal-type (Kv4.x) potassium channel pore blockers from scorpion venoms. Sheng Li Xue Bao 2015; 67:248-254. [PMID: 26109297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Voltage-gated potassium channels (Kv4.1, Kv4.2 and Kv4.3) encoded by the members of the KCND/Kv4 (Shal) channel family mediate the native, fast inactivating (A-type) K(+) current (IA) described both in heart and neurons. This IA current is specifically blocked by short scorpion toxins that belong to the α-KTx15 subfamily and which act as pore blockers, a different mode of action by comparison to spider toxins known as gating modifiers. This review summarizes our present chemical and pharmacological knowledge on the α-KTx15 toxins.
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Affiliation(s)
- Pierre Edouard Bougis
- Aix-Marseille University, The National Center for Scientific Research (CNRS), Research Center for Neurobiology and Neurophysiology of Marseille UMR7286, 13344, Marseille, France.
| | - Marie-France Martin-Eauclaire
- Aix-Marseille University, The National Center for Scientific Research (CNRS), Research Center for Neurobiology and Neurophysiology of Marseille UMR7286, 13344, Marseille, France
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Martin-Eauclaire MF, Bosmans F, Céard B, Diochot S, Bougis PE. A first exploration of the venom of the Buthus occitanus scorpion found in southern France. Toxicon 2014; 79:55-63. [PMID: 24418174 DOI: 10.1016/j.toxicon.2014.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/20/2013] [Accepted: 01/01/2014] [Indexed: 11/28/2022]
Abstract
Even though Buthus occitanus scorpions are found throughout the Mediterranean region, a lack of distinctive characteristics has hampered their classification into different subspecies. Yet, stings from this particular scorpion family are reported each year to result in pain followed by various toxic symptoms. In order to determine the toxicity origin of the rare French B. occitanus Amoreux scorpion, we collected several specimens and studied their venom composition using a nano ultra high performance liquid chromatography and matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (nano UHPLC/MALDI-TOF-MS) automated workflow combined with an enzyme-linked immunosorbent assay (ELISA) approach. Moreover, we compared this dataset to that obtained from highly lethal Androctonus australis and Androctonus mauretanicus scorpions collected in North Africa. As a result, we found that the B. occitanus Amoreux venom is toxic to mice, an observation that is most likely caused by venom components that inhibit voltage-gated sodium channel inactivation. Moreover, we identified similarities in venom composition between B. occitanus scorpions living in the South of France and other Buthidae collected in Morocco and Algeria. As such, the results of this study should be taken into consideration when treating stings from the B. occitanus species living in the South of France.
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Affiliation(s)
- Marie-France Martin-Eauclaire
- Aix Marseille Université, CNRS, CRN2M UMR7286, Faculté de Médecine, Campus Nord, CS80011, Bd Pierre Dramard, F-13344 Marseille Cedex 15, 13015 Marseille, France
| | - Frank Bosmans
- Department of Physiology, Johns Hopkins University-School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University-School of Medicine, Baltimore, MD 21205, USA
| | - Brigitte Céard
- Aix Marseille Université, CNRS, CRN2M UMR7286, Faculté de Médecine, Campus Nord, CS80011, Bd Pierre Dramard, F-13344 Marseille Cedex 15, 13015 Marseille, France
| | - Sylvie Diochot
- CNRS, IPMC UMR 6097, 06560, Sophia-Antipolis, Valbonne, France
| | - Pierre E Bougis
- Aix Marseille Université, CNRS, CRN2M UMR7286, Faculté de Médecine, Campus Nord, CS80011, Bd Pierre Dramard, F-13344 Marseille Cedex 15, 13015 Marseille, France.
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Martin-Eauclaire MF, Benoit E, Marchot P, Barbier J, Molgó J, Servent D. Special issue on «Toxins: from threats to benefits». Toxicon 2013; 75:1-2. [PMID: 23927926 DOI: 10.1016/j.toxicon.2013.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abbas N, Gaudioso-Tyzra C, Bonnet C, Gabriac M, Amsalem M, Lonigro A, Padilla F, Crest M, Martin-Eauclaire MF, Delmas P. The scorpion toxin Amm VIII induces pain hypersensitivity through gain-of-function of TTX-sensitive Na+ channels. Pain 2013; 154:1204-15. [DOI: 10.1016/j.pain.2013.03.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 02/27/2013] [Accepted: 03/25/2013] [Indexed: 10/27/2022]
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Martin-Eauclaire MF, Granjeaud S, Belghazi M, Bougis PE. Achieving automated scorpion venom mass fingerprinting (VMF) in the nanogram range. Toxicon 2013; 69:211-8. [DOI: 10.1016/j.toxicon.2013.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/11/2013] [Accepted: 03/01/2013] [Indexed: 10/27/2022]
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Maffie JK, Dvoretskova E, Bougis PE, Martin-Eauclaire MF, Rudy B. Dipeptidyl-peptidase-like-proteins confer high sensitivity to the scorpion toxin AmmTX3 to Kv4-mediated A-type K+ channels. J Physiol 2013; 591:2419-27. [PMID: 23440961 DOI: 10.1113/jphysiol.2012.248831] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
K+ channels containing Kv4.2 and Kv4.3 pore-forming subunits mediate most of the subthreshold-operating somatodendritic A-type K+ current in CNS neurons. These channels are believed to be important in regulating the frequency of repetitive firing, the backpropagation of action potential into dendrites, and dendritic integration and plasticity. Moreover, they have been implicated in several diseases from pain to epilepsy and autism spectrum disorders. The lack of toxins that specifically and efficiently block these channels has hampered studies aimed at confirming their functional role and their involvement in disease. AmmTX3 and other related members of the α-KTX15 family of scorpion toxins have been shown to block the A-type K+ current in cultured neurons, but their specificity has been questioned because the toxins do not efficiently block the currents mediated by Kv4.2 or Kv4.3 subunits expressed in heterologous cells. Here we show that the high-affinity blockade of Kv4.2 and Kv4.3 channels by AmmTX3 depends on the presence of the auxiliary subunits DPP6 and DPP10. These proteins are thought to be components of the Kv4 channel complex in neurons and to be important for channel expression in dendrites. These studies validate the use of AmmTX3 as a blocker of the Kv4-mediated A-type K+ current in neurons.
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Affiliation(s)
- Jon K Maffie
- Smilow Neuroscience Program, NYU School of Medicine, 522 First Avenue, New York, NY 10016, USA
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Ladjel-Mendil A, Martin-Eauclaire MF, Laraba-Djebari F. Neuropathophysiological effect and immuno-inflammatory response induced by kaliotoxin of androctonus scorpion venom. Neuroimmunomodulation 2013; 20:99-106. [PMID: 23295619 DOI: 10.1159/000345706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/06/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Kaliotoxin (KTX) is a neurotoxin purified from Androctonus scorpion venom. Purification and pharmacological and immunological characterization of this neurotoxin has been extensively studied, but its biological effects have not. The ability of KTX to induce neuropathophysiological and immuno-inflammatory effects was investigated. METHODS NMRI mice were injected with a sublethal dose of KTX (20 ng/20 g of body weight) or saline solution via the intra-cerebro-ventricular route. Tissue damage and immunological biomarkers such as eosinophil peroxidase (EPO), myeloperoxidase (MPO), and nitric oxide (NO) were analyzed in serum, brain, lung, and heart tissue. Protein levels, LDH, and CPK activities were also determined in serum 24 h after injection. RESULTS In this study, KTX injection induced severe alterations in the cerebral cortex, myocardium, and pulmonary parenchyma. Tissue damage was correlated with seric increase in creatine kinase and lactate dehydrogenase activities. KTX also induced an immuno-inflammatory response distinguished by cell infiltration characterized by a significant increase in EPO and MPO activities in the brain, heart, and lungs. This infiltration was also associated with an increase in albumin, α-, β-, and γ-globulin fractions, and NO release. CONCLUSION KTX binding to its targets in CNS (Kv1.1 and Kv1.3 channels) may induce severe modifications in the structure and function of various organs associated with the activation of immuno-inflammatory reactions.
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Affiliation(s)
- Amina Ladjel-Mendil
- USTHB, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
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Martin-Eauclaire MF, Abbas N, Bougis PE, Guieu R. 176. Is the Endogenous Opioid System Involved in the Antalgic Effect of Scorpion Toxins in Mice? Toxicon 2012. [DOI: 10.1016/j.toxicon.2012.04.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Martin-Eauclaire MF, Bougis PE. 179. Automated Mass Fingerprinting of Scorpion Venoms in the Nanogram Range. Toxicon 2012. [DOI: 10.1016/j.toxicon.2012.04.180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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di Tommaso A, Juste MO, Martin-Eauclaire MF, Dimier-Poisson I, Billiald P, Aubrey N. Diabody mixture providing full protection against experimental scorpion envenoming with crude Androctonus australis venom. J Biol Chem 2012; 287:14149-56. [PMID: 22375011 PMCID: PMC3340170 DOI: 10.1074/jbc.m112.348912] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Indexed: 01/24/2023] Open
Abstract
Androctonus australis is primarily involved in envenomations in North Africa, notably in Tunisia and Algeria, and constitutes a significant public health problem in this region. The toxicity of the venom is mainly due to various neurotoxins that belong to two distinct structural and immunological groups, group I (the AahI and AahIII toxins) and group II (AahII). Here, we report the use of a diabody mixture in which the molar ratio matches the characteristics of toxins and polymorphism of the venom. The mixture consists of the Db9C2 diabody (anti-group I) and the Db4C1op diabody (anti-AahII), the latter being modified to facilitate in vitro production and purification. The effectiveness of the antivenom was tested in vivo under conditions simulating scorpion envenomation. The intraperitoneal injection of 30 μg of the diabody mixture protected almost all the mice exposed to 3 LD(50) s.c. of venom. We also show that the presence of both diabodies is necessary for the animals to survive. Our results are the first demonstration of the strong protective power of small quantities of antivenom used in the context of severe envenomation with crude venom.
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Affiliation(s)
- Anne di Tommaso
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | - Matthieu O. Juste
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | | | - Isabelle Dimier-Poisson
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | | | - Nicolas Aubrey
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
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Fabrichny IP, Mondielli G, Conrod S, Martin-Eauclaire MF, Bourne Y, Marchot P. Structural insights into antibody sequestering and neutralizing of Na+ channel α-type modulator from old world scorpion venom. J Biol Chem 2012; 287:14136-48. [PMID: 22371498 DOI: 10.1074/jbc.m111.315382] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Old World scorpion Androctonus australis hector (Aah) produces one of the most lethal venoms for humans. Peptidic α-toxins AahI to AahIV are responsible for its potency, with AahII accounting for half of it. All four toxins are high affinity blockers of the fast inactivation phase of mammalian voltage-activated Na(+) channels. However, the high antigenic polymorphism of α-toxins prevents production of a polyvalent neutralizing antiserum, whereas the determinants dictating their trapping by neutralizing antibodies remain elusive. From an anti-AahII mAb, we generated an antigen binding fragment (Fab) with high affinity and selectivity for AahII and solved a 2.3 Å-resolution crystal structure of the complex. Sequestering of the C-terminal region of the bound toxin within a groove formed by the Fab combining loops is associated with a toxin orientation and main and side chain conformations that dictate the AahII antigenic specificity and efficient neutralization. From an anti-AahI mAb, we also preformed and crystallized a high affinity AahI-Fab complex. The 1.6 Å-resolution structure solved revealed a Fab molecule devoid of a bound AahI and with combining loops involved in packing interactions, denoting expulsion of the bound antigen upon crystal formation. Comparative analysis of the groove-like combining site of the toxin-bound anti-AahII Fab and planar combining surface of the unbound anti-AahI Fab along with complementary data from a flexible docking approach suggests occurrence of distinctive trapping orientations for the two toxins relative to their respective Fab. This study provides complementary templates for designing new molecules aimed at capturing Aah α-toxins and suitable for immunotherapy.
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Affiliation(s)
- Igor P Fabrichny
- Faculté de Médecine Secteur Nord, Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille, CRN2M, CNRS/Aix-Marseille Université UMR-6231, Institut Fédératif de Recherche Jean Roche, CS80011, F-13344 Marseille cedex 15, France
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Raouraoua-Boukari R, Sami-Merah S, Hammoudi-Triki D, Martin-Eauclaire MF, Laraba-Djebari F. Immunomodulation of the inflammatory response induced by Androctonus australis hector neurotoxins: biomarker interactions. Neuroimmunomodulation 2012; 19:103-10. [PMID: 22248726 DOI: 10.1159/000330241] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 06/03/2011] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE Androctonus australis hector (Aah) is the most dangerous scorpion in the Maghreb countries. Its venom contains three major neurotoxins (Aah I, Aah II and Aah III), which are responsible for almost all the lethal effects caused in mammals. These toxins act on the voltage-gated sodium channels of excitable cells. The targets and the lethal effects of these toxins have been extensively studied. However, their effects on the induced immune response after envenoming have not deeply elicited. We therefore investigated the effects induced by Aah venom and its toxic components, mainly its main toxin Aah II, on the activation of the inflammatory process. METHODS Wistar rats were injected by intraperitoneal route with a sublethal dose of Aah venom, FTox-G50, the purified Aah II toxin or with 400 μl of sterile physiological saline solution. Immunological biomarkers such as MPO, NO and ICAM-1 were analyzed in serum in lung tissue. Cytokine levels were also determined in serum at 3, 6 and 24 h after envenoming. RESULTS We report in this study that intraperitoneal injection of the venom or its toxins (the whole toxic fraction or Aah II toxin) caused an inflammatory reaction involving increased neutrophil release into blood and neutrophil accumulation in lung tissue. This cell infiltration was associated with the release of NO, histamine, cytokines (IL-1, IL-6, IL-12, IL-4 and IL-5) and ICAM. CONCLUSION Aah II binding to its targets, in this case Na⁺ channels, may induce a cascade of events such as inflammatory mediator release and neutrophil migration that could contribute to the exacerbation of the systemic inflammatory response and the development of lung injury following scorpion envenoming.
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Affiliation(s)
- Ryma Raouraoua-Boukari
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, Université des Sciences et de la Technologie «Houari Boumédienne», Alger, Algérie
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Gaudioso C, Hao J, Martin-Eauclaire MF, Gabriac M, Delmas P. Menthol pain relief through cumulative inactivation of voltage-gated sodium channels. Pain 2011; 153:473-484. [PMID: 22172548 DOI: 10.1016/j.pain.2011.11.014] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 09/19/2011] [Accepted: 11/14/2011] [Indexed: 01/02/2023]
Abstract
Menthol is a natural compound of plant origin known to produce cool sensation via the activation of the TRPM8 channel. It is also frequently part of topical analgesic drugs available in a pharmacy, although its mechanism of action is still unknown. Compelling evidence indicates that voltage-gated Na(+) channels are critical for experiencing pain sensation. We tested the hypothesis that menthol may block voltage-gated Na(+) channels in dorsal root ganglion (DRG) neurons. By use of a patch clamp, we evaluated the effects of menthol application on tetrodotoxin (TTX)-resistant Nav1.8 and Nav1.9 channel subtypes in DRG neurons, and on TTX-sensitive Na(+) channels in immortalized DRG neuron-derived F11 cells. The results indicate that menthol inhibits Na(+) channels in a concentration-, voltage-, and frequency-dependent manner. Menthol promoted fast and slow inactivation states, causing use-dependent depression of Na(+) channel activity. In current clamp recordings, menthol inhibited firing at high-frequency stimulation with minimal effects on normal neuronal activity. We found that low concentrations of menthol cause analgesia in mice, relieving pain produced by a Na(+) channel-targeting toxin. We conclude that menthol is a state-selective blocker of Nav1.8, Nav1.9, and TTX-sensitive Na(+) channels, indicating a role for Na(+) channel blockade in the efficacy of menthol as topical analgesic compound.
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Affiliation(s)
- Christelle Gaudioso
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, Aix-Marseille Université, UMR 6231, CNRS, CS80011, Bd Pierre Dramard, 13344 Marseille Cedex 15, France
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Bosmans F, Puopolo M, Martin-Eauclaire MF, Bean BP, Swartz KJ. Functional properties and toxin pharmacology of a dorsal root ganglion sodium channel viewed through its voltage sensors. ACTA ACUST UNITED AC 2011; 138:59-72. [PMID: 21670206 PMCID: PMC3135324 DOI: 10.1085/jgp.201110614] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The voltage-activated sodium (Nav) channel Nav1.9 is expressed in dorsal root ganglion (DRG) neurons where it is believed to play an important role in nociception. Progress in revealing the functional properties and pharmacological sensitivities of this non-canonical Nav channel has been slow because attempts to express this channel in a heterologous expression system have been unsuccessful. Here, we use a protein engineering approach to dissect the contributions of the four Nav1.9 voltage sensors to channel function and pharmacology. We define individual S3b–S4 paddle motifs within each voltage sensor, and show that they can sense changes in membrane voltage and drive voltage sensor activation when transplanted into voltage-activated potassium channels. We also find that the paddle motifs in Nav1.9 are targeted by animal toxins, and that these toxins alter Nav1.9-mediated currents in DRG neurons. Our results demonstrate that slowly activating and inactivating Nav1.9 channels have functional and pharmacological properties in common with canonical Nav channels, but also show distinctive pharmacological sensitivities that can potentially be exploited for developing novel treatments for pain.
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Affiliation(s)
- Frank Bosmans
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA. Frank.Bosmans@-nih.gov
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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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [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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Zhu S, Gao B, Aumelas A, del Carmen Rodríguez M, Lanz-Mendoza H, Peigneur S, Diego-Garcia E, Martin-Eauclaire MF, Tytgat J, Possani LD. MeuTXKβ1, a scorpion venom-derived two-domain potassium channel toxin-like peptide with cytolytic activity. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2010; 1804:872-83. [DOI: 10.1016/j.bbapap.2009.12.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/22/2009] [Accepted: 12/23/2009] [Indexed: 11/24/2022]
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Bosmans F, Puopolo M, Martin-Eauclaire MF, Bean BP, Swartz KJ. Defining the Voltage Sensor Properties and Pharmacology of Nav1.9. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.4215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Legros C, Guette C, Martin-Eauclaire MF, Goyffon M, Tortajada J. Affinity capture using chimeric membrane proteins bound to magnetic beads for rapid ligand screening by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Commun Mass Spectrom 2009; 23:745-755. [PMID: 19204930 DOI: 10.1002/rcm.3939] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The rapid and specific detection of therapeutically important ligands in complex mixtures, that may bind to membrane proteins, remains challenging for many research laboratories and pharmaceutical industries. Through its use in the development of screening assays, mass spectrometry (MS) is currently experiencing a period of tremendous expansion. In the study presented here, we took advantage of the remarkable stability properties of a bacterial membrane protein, the KcsA K+ channel, produced in E. coli and purified as a tetrameric protein in the presence of a detergent. This membrane protein can subserve as a molecular template to display the pore-forming region of human K+ channels, which are considered as targets in the search for inhibitory ligands. The engineered chimeric proteins were linked to metal-bound magnetic beads, for the screening of complex peptide mixtures, such as that of scorpion venoms. The affinity-captured scorpion toxins were eluted prior to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), and to nano-electrospray ionization tandem mass QqTOF mass spectrometry (MS/MS) analysis. The de novo sequence of the toxins was deduced by combining the MS/MS fragmentation of the reduced form (up to the 33 first residues) and the trypsin digest peptides of the native toxins. This affinity-capture screening assay led to the isolation and characterization of potent and specific ligands of the human K+ channel, Kv1.3. The affinity-capture procedure is fast and reproducible. When linked to magnetic beads, the chimeric membrane protein can be re-used several times without losing any of its selectivity or specificity. This assay also benefits from the fact that it requires minimal amounts of animal venoms or complex mixtures, which can be expensive or difficult to procure.
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Affiliation(s)
- Christian Legros
- Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement (LAMBE), Université d'Evry Val d'Essonne, CNRS UMR 8587, Bd F. Mitterrand, 91025 Evry, France.
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Bosmans F, Martin-Eauclaire MF, Swartz KJ. Using Potassium Channels As Reporters To Deconstruct The Function And Pharmacology Of Sodium Channel Voltage Sensors. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abbas N, Belghazi M, Abdel-Mottaleb Y, Tytgat J, Bougis PE, Martin-Eauclaire MF. A new Kaliotoxin selective towards Kv1.3 and Kv1.2 but not Kv1.1 channels expressed in oocytes. Biochem Biophys Res Commun 2008; 376:525-30. [DOI: 10.1016/j.bbrc.2008.09.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 09/05/2008] [Indexed: 01/02/2023]
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Sami-Merah S, Hammoudi-Triki D, Martin-Eauclaire MF, Laraba-Djebari F. Combination of two antibody fragments F(ab′)2/Fab: An alternative for scorpion envenoming treatment. Int Immunopharmacol 2008; 8:1386-94. [DOI: 10.1016/j.intimp.2008.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 05/18/2008] [Accepted: 05/19/2008] [Indexed: 11/26/2022]
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Abdel-Mottaleb Y, Corzo G, Martin-Eauclaire MF, Satake H, Céard B, Peigneur S, Nambaru P, Bougis PE, Possani LD, Tytgat J. A common "hot spot" confers hERG blockade activity to alpha-scorpion toxins affecting K+ channels. Biochem Pharmacol 2008; 76:805-15. [PMID: 18687312 DOI: 10.1016/j.bcp.2008.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 02/01/2023]
Abstract
While alpha-KTx peptides are generally known for their modulation of the Shaker-type and the Ca(2+)-activated potassium channels, gamma-KTxs are associated with hERG channels modulation. An exception to the rule is BmTx3 which belongs to subfamily alpha-KTx15 and can block hERG channels. To explain the peculiar behavior of BmTx3, a tentative "hot spot" formed of 2 basic residues (R18 and K19) was suggested but never further studied [Huys I, et al. BmTx3, a scorpion toxin with two putative functional faces separately active on A-type K(+) and HERG currents. Biochem J 2004;378:745-52]. In this work, we investigated if the "hot spot" is a commonality in subfamily alpha-KTx15 by testing the effect of (AmmTx3, Aa1, discrepin). Furthermore, single mutations altering the "hot spot" in discrepin, have introduced for the very first time a hERG blocking activity to a previously non-active alpha-KTx. Additionally, we could extend our results to other alpha-KTx subfamily members belonging to alpha-KTx1, 4 and 6, therefore, the "hot spot" represents a common pharmacophore serving as a predictive tool for yet to be discovered alpha-KTxs.
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Affiliation(s)
- Yousra Abdel-Mottaleb
- Laboratory of Toxicology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
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Ader C, Schneider R, Hornig S, Velisetty P, Wilson EM, Lange A, Giller K, Ohmert I, Martin-Eauclaire MF, Trauner D, Becker S, Pongs O, Baldus M. A structural link between inactivation and block of a K+ channel. Nat Struct Mol Biol 2008; 15:605-12. [DOI: 10.1038/nsmb.1430] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 04/04/2008] [Indexed: 11/09/2022]
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Juste M, Martin-Eauclaire MF, Devaux C, Billiald P, Aubrey N. Using a recombinant bispecific antibody to block Na+ -channel toxins protects against experimental scorpion envenoming. Cell Mol Life Sci 2007; 64:206-18. [PMID: 17187174 DOI: 10.1007/s00018-006-6401-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In recent years, several molecular engineering methods of designing bispecific antibodies in various formats have been developed. Tandem-scFvs comprising two scFvs fused together via a peptide are 55-kDa molecules, and are one of the most promising and most straightforward approaches to bispecific antibody production. We report an attempt to design more effective antivenoms to the Androctonus australis scorpion using murine scFvs as building blocks to create a unique bispecific molecule that neutralizes the potent neurotoxins AahI and AahII. The tandem-scFv was produced in recombinant bacteria, purified by immobilized metal ion affinity chromatography, and analyzed by polyacrylamide gel electrophoresis, Western blot, gel filtration, mass spectrometry, and direct and competitive radioimmunoassay. In vivo, it neutralized the binding of the AahI and AahII toxins to their receptor, and protected mice against experimental envenomation. The findings reported here highlight the potential of recombinant antibody fragments for protecting against scorpion venom toxicity.
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Affiliation(s)
- M Juste
- Faculté de Pharmacie, UMR Université-INRA 483, 31 Avenue Monge, 37200, Tours, France
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Legros C, Martin-Eauclaire MF, Pongs O, Bougis PE. Toxin binding to chimeric K+ channels immobilised on a solid nitrocellulose support. Biochem Biophys Res Commun 2006; 353:1086-90. [PMID: 17198678 DOI: 10.1016/j.bbrc.2006.12.156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 12/20/2006] [Indexed: 09/30/2022]
Abstract
In this work, we used a panel prokaryote/eukaryote K+ channel chimeras to generate K+ channel arrays. Their behaviour in solution was compared with that when spotted on a nitrocellulose-supported film and their responses to selective high affinity ligands, including polypeptide toxins and TEA, were studied.
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Affiliation(s)
- Christian Legros
- ZMNH, Universität Hamburg, Zentrum für Molekulare Neurobiologie, Institut für Neurale Signalverarbeitung, Falkenried 94, 20251 Hamburg, Germany
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Bosmans F, Martin-Eauclaire MF, Tytgat J. Differential effects of five 'classical' scorpion beta-toxins on rNav1.2a and DmNav1 provide clues on species-selectivity. Toxicol Appl Pharmacol 2006; 218:45-51. [PMID: 17118417 PMCID: PMC1868420 DOI: 10.1016/j.taap.2006.10.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 10/05/2006] [Accepted: 10/11/2006] [Indexed: 12/19/2022]
Abstract
In general, scorpion beta-toxins have been well examined. However, few in-depth studies have been devoted to species selectivity and affinity comparisons on the different voltage-activated Na(+) channels since they have become available as cloned channels that can be studied in heterologous expression systems. As a result, their classification is largely historical and dates from early in vivo experiments on mice and cockroach and fly larvae. In this study, we aimed to provide an updated overview of selectivity and affinity of scorpion beta-toxins towards voltage-activated Na(+) channels of vertebrates or invertebrates. As pharmacological tools, we used the classic beta-toxins AaHIT, Css II, Css IV, Css VI and Ts VII and tested them on the neuronal vertebrate voltage-activated Na(+) channel, rNa(v)1.2a. For comparison, its invertebrate counterpart, DmNav1, was also tested. Both these channels were expressed in Xenopus laevis oocytes and the currents measured with the two-electrode voltage-clamp technique. We supplemented this data with several binding displacement studies on rat brain synaptosomes. The results lead us to propose a general classification and a novel nomenclature of scorpion beta-toxins based on pharmacological activity.
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Affiliation(s)
- Frank Bosmans
- Laboratory of Toxicology, University of Leuven, O&N 2, Postbus 922, Herestraat 49, 3000 Leuven, Belgium
- * To whom correspondence should be addressed: J. Tytgat, Laboratory of Toxicology, University of Leuven, O&N 2, Postbus 922, Herestraat 49, 3000 Leuven, Belgium. Fax: +3216323405, Tel.: +3216323403. E-mail: ; http://www.toxicology.be
| | - Marie-France Martin-Eauclaire
- CNRS FRE 2732, Biologie des Interactions Moléculaires et Cellulaires, Faculté de Médecine secteur Nord, Institut Jean Roche, Université de la Méditerranée, Bd Pierre Dramard, 13916, Marseille, Cedex 20, France
| | - Jan Tytgat
- Laboratory of Toxicology, University of Leuven, O&N 2, Postbus 922, Herestraat 49, 3000 Leuven, Belgium
- * To whom correspondence should be addressed: J. Tytgat, Laboratory of Toxicology, University of Leuven, O&N 2, Postbus 922, Herestraat 49, 3000 Leuven, Belgium. Fax: +3216323405, Tel.: +3216323403. E-mail: ; http://www.toxicology.be
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Vacher H, Diochot S, Bougis PE, Martin-Eauclaire MF, Mourre C. Kv4 channels sensitive to BmTX3 in rat nervous system: autoradiographic analysis of their distribution during brain ontogenesis. Eur J Neurosci 2006; 24:1325-40. [PMID: 16987219 DOI: 10.1111/j.1460-9568.2006.05020.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The binding site distribution of sBmTX3, a chemically synthesized toxin originally purified from the venom of the scorpion Buthus martensi, was investigated in adult and developing rat brain, using patch-clamp experiments and quantitative autoradiography. The molecular basis of these sBmTX3 sites was analysed by electrophysiology on transient Kv currents recorded in mammalian transfected cells. The rapidly activating and inactivating Kv4.1 current was inhibited by sBmTX3 (IC50, 105 nM). The inhibition was less effective on Kv4.2 and Kv4.3 channels and the toxin did not affect other transient currents such as Kv1.4 and Kv3.4. The distribution of the 125I-sBmTX3 binding sites was heterogeneous, with a 113-fold difference between the highest and the lowest densities in adult rat brain. The site density was particularly important in the caudate-putamen and accumbens nucleus, thalamus, hippocampal formation and cerebellum. The affinity of sBmTX3 remained constant during brain ontogenesis. The level of sBmTX3 binding sites was very low in prenatal and postnatal stages to postnatal day (P)12 but drastically increased from P15 in the major part of the studied structures except in the CA3 hippocampal field where the density was very high from P6. Thus, the distribution of sBmTX3 binding sites in rat brain and its electrophysiological characteristics suggest that sBmTX3 specifically binds to the Kv4 subfamily of K channels.
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Affiliation(s)
- Hélène Vacher
- CNRS, UMR 6149, Neurobiologie des Processus Mnésiques, Université de Provence, Pôle 3C, Centre St Charles, 3 Place Victor Hugo, 13331 Marseille cedex 03, France
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Lange A, Giller K, Hornig S, Martin-Eauclaire MF, Pongs O, Becker S, Baldus M. Toxin-induced conformational changes in a potassium channel revealed by solid-state NMR. Nature 2006; 440:959-62. [PMID: 16612389 DOI: 10.1038/nature04649] [Citation(s) in RCA: 359] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Accepted: 02/15/2006] [Indexed: 11/08/2022]
Abstract
The active site of potassium (K+) channels catalyses the transport of K+ ions across the plasma membrane--similar to the catalytic function of the active site of an enzyme--and is inhibited by toxins from scorpion venom. On the basis of the conserved structures of K+ pore regions and scorpion toxins, detailed structures for the K+ channel-scorpion toxin binding interface have been proposed. In these models and in previous solution-state nuclear magnetic resonance (NMR) studies using detergent-solubilized membrane proteins, scorpion toxins were docked to the extracellular entrance of the K+ channel pore assuming rigid, preformed binding sites. Using high-resolution solid-state NMR spectroscopy, here we show that high-affinity binding of the scorpion toxin kaliotoxin to a chimaeric K+ channel (KcsA-Kv1.3) is associated with significant structural rearrangements in both molecules. Our approach involves a combined analysis of chemical shifts and proton-proton distances and demonstrates that solid-state NMR is a sensitive method for analysing the structure of a membrane protein-inhibitor complex. We propose that structural flexibility of the K+ channel and the toxin represents an important determinant for the high specificity of toxin-K+ channel interactions.
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Affiliation(s)
- Adam Lange
- Max Planck Institute for Biophysical Chemistry, Department of NMR-Based Structural Biology, 37077 Göttingen, Germany
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Alami M, Céard B, Legros C, Bougis PE, Martin-Eauclaire MF. Genomic characterisation of the toxin Amm VIII from the scorpion Androctonus mauretanicus mauretanicus. Toxicon 2006; 47:531-6. [PMID: 16533515 DOI: 10.1016/j.toxicon.2006.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 12/28/2005] [Accepted: 01/06/2006] [Indexed: 11/20/2022]
Abstract
The genomic DNA sequence encoding the scorpion toxin Amm VIII was amplified from genomic DNA of the scorpion Androctonus mauretanicus mauretanicus from Morocco, subcloned and sequenced. An intron, with a high A+T content (73.5%), split a Gly codon at the end of the precursor signal peptide and the consensus GT/AG splice junction was identified in the Amm VIII gene. This intron of only 166 bp is the smallest intron described so far for a long-chain scorpion toxin gene. In addition, this study led to the identification of three new toxin-related genes. From the deduced amino acid sequences of the encoded precursor proteins, we found that the mature putative toxins were highly similar to the scorpion toxins Leiurus quinquestriatus quinquestriatus IV and Odonthobuthus doriae 1.
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Affiliation(s)
- Meriem Alami
- Institut Pasteur du Maroc, 1 Rue Abou Kacem Ezzahroui, Casablanca, Morocco
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Grolleau F, Stankiewicz M, Kielbasiewicz E, Martin-Eauclaire MF, Lavialle C, De Vente J, Lapied B. Indirect activation of neuronal noncapacitative Ca2+entry is the final step involved in the neurotoxic effect ofTityus serrulatusscorpion β-toxin. Eur J Neurosci 2006; 23:1465-78. [PMID: 16553610 DOI: 10.1111/j.1460-9568.2006.04667.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interweaving strategies of electrophysiology, calcium imaging and immunocytochemistry bring new insights into the mode of action of the Brazilian scorpion Tityus serrulatusbeta-toxin VII. Pacemaker dorsal unpaired median neurons isolated from the cockroach central nervous system were used to study the effects of toxin VII. In current-clamp, 50 nm toxin VII produced a membrane depolarization and reduced spiking. At 200 nM, depolarization associated with multiphasic effects was seen. After artificial hyperpolarization, plateau potentials on which spontaneous electrical activity appeared were observed. In voltage clamp, toxin VII induced a negative shift of the voltage dependence of sodium current activation without significant effect on steady-state inactivation. In addition, toxin VII produced a permanent TTX-sensitive holding inward current, indicating that background sodium channels were targeted by beta-toxin. Cell-attached patch recordings indicated that these channels were switched from unclustered single openings to current fluctuating between distinct subconductance levels exhibiting increased open probability and open-time distribution. Toxin VII also produced a TTX-sensitive [Ca2+]i rise. Immunostaining with Cav2.2(alpha1b) antibodies and calcium imaging data obtained with omega-CgTx GVIA indicated that N-type high-voltage-activated calcium channels initiated calcium influx and were an essential intermediate in the pathway linking toxin VII-modified sodium channels to the activation of an additional route for calcium entry. By using inhibitors of (i) noncapacitative calcium entry (inhibitor LOE-908), (ii) NO-sensitive guanylyl cyclase (ODQ) and (iii) phosphodiesterase 2 (EHNA), together with cGMP antibodies, we demonstrated that noncapacitative calcium entry was the final step in a complex combination of events that was initiated by toxin VII-alteration of sodium channels and then involved successive activation of other membrane ion channels.
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Affiliation(s)
- Françoise Grolleau
- Laboratoire RCIM UPRES EA 2647, Université d'Angers, Faculté des Sciences, 2 bd Lavoisier, F-49045 Angers cedex, France.
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Prochnicka-Chalufour A, Corzo G, Satake H, Martin-Eauclaire MF, Murgia AR, Prestipino G, D'Suze G, Possani LD, Delepierre M. Solution Structure of Discrepin, a New K+-Channel Blocking Peptide from the α-KTx15 Subfamily,. Biochemistry 2006; 45:1795-804. [PMID: 16460026 DOI: 10.1021/bi0519248] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Discrepin, isolated from the venom of the Venezuelan scorpion Tityus discrepans, blocks preferentially the I(A) currents of the voltage-dependent K+ channel of rat cerebellum granular cells in an irreversible way. It contains 38 amino acid residues with a pyroglutamic acid as the N-terminal residue [D'Suze, G., Batista, C. V., Frau, A., Murgia, A. R., Zamudio, F. Z., Sevcik, C., Possani, L. D., and Prestipino, G. (2004) Arch. Biochem. Biophys. 430, 256-63]. It is the most distinctive member of the alpha-KTx15 subfamily of scorpion toxins. Six members of the alpha-KTx15 subfamily have been reported so far to be specific for this subtype of the K+ channel; however, none of them have had their three-dimensional structure determined, and no information for the residues possibly involved in channel recognition and binding is available. Natural discrepin (n-discrepin) was prepared from scorpion venom, and its synthetic analogue (s-discrepin) was obtained by solid-phase synthesis. Analysis of two-dimensional 1H NMR spectra of n- and s-discrepin indicates that both peptides have the same structure. Here we report the solution structure of s-discrepin determined by NMR using 565 meaningful distance constraints derived from the volume integration of the two-dimensional NOESY spectrum, 22 dihedrals, and three hydrogen bonds. Discrepin displays the alpha/beta scaffold, characteristic of scorpion toxins. Some features of the proposed interacting surface between the toxin and channel as well as the opposite "alpha-helix surface" are discussed in comparison with those of other alpha-KTx15 members. Both n- and s-discrepin exhibit similar physiological actions as verified by patch-clamp and binding and displacement experiments.
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Affiliation(s)
- Ada Prochnicka-Chalufour
- Unité de RMN des Biomolécules URA 2185 CNRS, Institut Pasteur, 28 Rue du Dr Roux, 75724 Paris Cedex 15, France
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Martin-Eauclaire MF, Ceard B, Bosmans F, Rosso JP, Tytgat J, Bougis PE. New “Birtoxin analogs” from Androctonus australis venom. Biochem Biophys Res Commun 2005; 333:524-30. [PMID: 15963953 DOI: 10.1016/j.bbrc.2005.05.148] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Accepted: 05/23/2005] [Indexed: 11/16/2022]
Abstract
From the venom of the scorpion Androctonus australis, we have isolated a new bioactive polypeptide termed AaBTX-L1. When tested on the insect voltage-gated Na(+) channel (para) of the fruit fly, this toxin was able to induce a clear shift in activation (V(1/2)), resulting in the opening of the channel at more negative membrane potentials. Furthermore, AaBTX-L1 was totally devoid of toxicity when injected into mice intracerebroventricularly and did not compete with radiolabeled voltage-gated K(+) and Na(+) channel toxins in binding experiments on rat brain synaptosomes. Using its N-terminal amino acid sequence to design degenerate primers, several clones were amplified by PCR from the A. australis venom gland cDNA library. As a consequence, seven full oligonucleotide sequences encoding "long-chain" polypeptides with only three disulfide bridges have been cloned for the first time and are described here. Remarkably, they share high similarity with the anti-insect toxin Birtoxin from Parabuthus transvaalicus.
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Affiliation(s)
- Marie-France Martin-Eauclaire
- CNRS FRE 2738, Ingénierie des Protéines, Faculté de Médecine secteur Nord, Institut Jean Roche, Université de la Méditerranée, Bd Pierre Dramard, 13916 Marseille 20, France.
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Legros C, Céard B, Vacher H, Marchot P, Bougis PE, Martin-Eauclaire MF. Expression of the standard scorpion alpha-toxin AaH II and AaH II mutants leading to the identification of some key bioactive elements. Biochim Biophys Acta Gen Subj 2005; 1723:91-9. [PMID: 15725394 DOI: 10.1016/j.bbagen.2005.01.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 01/12/2005] [Accepted: 01/13/2005] [Indexed: 10/25/2022]
Abstract
The AaH II toxin from the scorpion Androctonus australis Hector is considered to be the standard alpha-toxin because it selectively binds with the highest known affinity to site 3 of mammalian voltage-activated Na+ channels (Na(v)) on rat brain synaptosomes but does not bind to insect synaptosomes. We generated two different constructs in pMALp allowing us to produce AaH II fused with the maltose-binding protein (MBP) in E. coli. We obtained reasonable amounts of recombinant AaH II after cleavage by enterokinase at the site DDDDK. We show that the introduction of a net negative charge at the C-terminus by the suppression of H64 amidation and the addition of an extra residue to the C-terminus (G65) led to fully active AaH II mutants, exhibiting exactly the same affinity as the native toxin for its target on rat brain synaptosomes. In contrast, the mutation of residue K58 into V, I or E residues drastically reduced toxin activity.
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Affiliation(s)
- Christian Legros
- Ingénierie des Protéines CNRS FRE 2738, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Secteur Nord, Université de la Méditerranée, Bd Pierre Dramard, 13916, Marseille, cedex 20, France
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Bosmans F, Martin-Eauclaire MF, Tytgat J. The depressant scorpion neurotoxin LqqIT2 selectively modulates the insect voltage-gated sodium channel. Toxicon 2005; 45:501-7. [PMID: 15733572 DOI: 10.1016/j.toxicon.2004.12.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 12/09/2004] [Accepted: 12/10/2004] [Indexed: 11/30/2022]
Abstract
LqqIT2 is a depressant neurotoxin present in the venom of the Leiurus quinquestriatus quinquestriatus scorpion, one of the world's most dangerous scorpions endemic to dry habitats in Africa and Asia. In order to determine its efficacy, potency and selectivity, LqqIT2 was subjected for the first time to an electrophysiological and pharmacological comparison between two different cloned sodium channels expressed in Xenopus laevis oocytes. Aside from typical beta-toxin effects, LqqIT2 also affected the inactivation process and ion selectivity of the insect voltage-gated sodium channel. The most interesting feature of LqqIT2 is its total insect-selectivity. At a concentration of 1 microM, the insect-voltage-gated sodium channel, para, was profoundly modulated while its mammalian counterpart, the rat brain Na(v)1.2 channel, was not affected. This trait offers excellent prospects for the development of novel insecticides.
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Affiliation(s)
- Frank Bosmans
- Laboratory of Toxicology, Faculty of Pharmacy, University of Leuven, E. Van Evenstraat 4, B-3000 Leuven, Belgium
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