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Liriodenine is a biologically active plant alkaloid with multiple effects on mammals, fungi, and bacteria, but has never been evaluated for insecticidal activity. Accordingly, liriodenine was applied topically in ethanolic solutions to adult female Anopheles gambiae, and found to be mildly toxic. Its lethality was synergized in mixtures with dimethyl sulfoxide and piperonyl butoxide. Recordings from the ventral nerve cord of larval Drosophila melanogaster showed that liriodenine was neuroexcitatory and reversed the inhibitory effect of 1 mM GABA at effective concentrations of 20-30 μM. GABA antagonism on the larval nervous system was equally expressed on both susceptible and cyclodiene-resistant rdl preparations. Acutely isolated neurons from Periplaneta americana were studied under patch clamp and inhibition of GABA-induced currents with an IC50 value of about 1 μM were observed. In contrast, bicuculline did not reverse the effects of GABA on cockroach neurons, as expected. In silico molecular models suggested reasonable structural concordance of liriodenine and bicuculline and isosteric hydrogen bond acceptor sites . This study is the first assessing of the toxicology of liriodenine on insects and implicates the GABA receptor as one likely neuronal target, where liriodenine might be considered an active chemical analog of bicuculline.
Quentin R.R. Coquerel; Fabien Démares; Werner J. Geldenhuys; Anne-Marie Le Ray; Dimitri Bréard; Pascal Richomme; Christian Legros; Edmund Norris; Jeffrey R. Bloomquist. Toxicon Toxicity and mode of action of the aporphine plant alkaloid liriodenine on the insect GABA receptor. Toxicon 2021, 1 .
AMA StyleQuentin R.R. Coquerel, Fabien Démares, Werner J. Geldenhuys, Anne-Marie Le Ray, Dimitri Bréard, Pascal Richomme, Christian Legros, Edmund Norris, Jeffrey R. Bloomquist. Toxicon Toxicity and mode of action of the aporphine plant alkaloid liriodenine on the insect GABA receptor. Toxicon. 2021; ():1.
Chicago/Turabian StyleQuentin R.R. Coquerel; Fabien Démares; Werner J. Geldenhuys; Anne-Marie Le Ray; Dimitri Bréard; Pascal Richomme; Christian Legros; Edmund Norris; Jeffrey R. Bloomquist. 2021. "Toxicon Toxicity and mode of action of the aporphine plant alkaloid liriodenine on the insect GABA receptor." Toxicon , no. : 1.
Veratridine (VTD), a selective activator of voltage-gated Na+ (Nav) channels, triggers contractile responses in mesenteric arteries (MA), by increasing intracellular Ca2+ mediated by Na+/Ca2+ exchanger (NCX) in smooth muscle cells (SMC). However, VTD induces endothelium-dependent relaxation of retinal and cremaster arteries. These opposite VTD-responses gives rise to the question as to whether Nav channels play a role in vascular tone. We aim to characterize the contribution of Nav channels to vascular tone in MA. Since Nav channels are expressed in SMC, endothelial cells (EC) and nerve terminal endings of arteries, our aim is also to identify those which are responsible of VTD-evoked vasomotor responses. The VTD-induced contractile responses of first order mesenteric arteries (FOMA) and cecolic arteries (CA) of mice were recorded by wire myography. EC were used to characterize Ca2+ responses using FURA-2 probe. Western blot and absolute RT-qPCR were used to characterize Nav channels and NCX expression. Nav1.2 channels are expressed in both SMC and EC of MA. VTD elicits contraction of FOMA, which is abolished by prazosin. Surprisingly, VTD induces relaxation of CA. This vasorelaxation is resistant to prazosin and supressed by atropine. VTD-induced relaxation is inhibited by eNO-synthase inhibitor (L-NNA) and NCX antagonists. Morever, NCX1 is the main NCX isoform expressed in EC. Finally, acetylcholine-induced Ca2+ reponses are inhibited by NCX antagonists in endothelial cells. VTD induces opposite contractile responses in isolated mesenteric arteries. In fact, VTD activates Nav channels of sympathetic neurons in FOMA, and parasympathetic neurons in CA, leading to noradrenaline and acetylcholine release, respectively. Thus, the vascular tone of both arteries are differently regulated by the autonomic nervous system. Finally, acetylcholine triggers Ca2+-activation of eNO-synthase mediated by NCX1 in CA.
J. Park; J. Frangieh; L. Réthoré; E. Roy-Vessieres; L. Grimaud; D. Henrion; C. Legendre; C. Legros. Activation of Nav channels by veratridine in mesenteric arteries: Contractile or relaxation responses? Archives of Cardiovascular Diseases Supplements 2021, 13, 187 .
AMA StyleJ. Park, J. Frangieh, L. Réthoré, E. Roy-Vessieres, L. Grimaud, D. Henrion, C. Legendre, C. Legros. Activation of Nav channels by veratridine in mesenteric arteries: Contractile or relaxation responses? Archives of Cardiovascular Diseases Supplements. 2021; 13 (2):187.
Chicago/Turabian StyleJ. Park; J. Frangieh; L. Réthoré; E. Roy-Vessieres; L. Grimaud; D. Henrion; C. Legendre; C. Legros. 2021. "Activation of Nav channels by veratridine in mesenteric arteries: Contractile or relaxation responses?" Archives of Cardiovascular Diseases Supplements 13, no. 2: 187.
Neonicotinoid insecticides are nicotine-derived molecules which exert acute neurotoxic effects over the insect central nervous system by activating nicotinic acetylcholine receptors (nAChRs). However, these receptors are also present in the mammalian central and peripheral nervous system, where the effects of neonicotinoids are faintly known. In mammals, cholinergic synapses are crucial for the control of vascular tone, blood pressure and skeletal muscle contraction. We therefore hypothesized that neonicotinoids could affect cholinergic networks in mammals and sought to highlight functional consequences of acute intoxication in rats with sub-lethal concentrations of the highly used acetamiprid (ACE) and clothianidin (CLO). In this view, we characterized their electrophysiological effects on rat
Joohee Park; Antoine Taly; Jennifer Bourreau; Frédéric De Nardi; Claire Legendre; Daniel Henrion; Nathalie Guérineau; Christian Legros; César Mattei; Hélène Tricoire-Leignel. Partial Agonist Activity of Neonicotinoids on Rat Nicotinic Receptors: Consequences over Epinephrine Secretion and In Vivo Blood Pressure. International Journal of Molecular Sciences 2021, 22, 5106 .
AMA StyleJoohee Park, Antoine Taly, Jennifer Bourreau, Frédéric De Nardi, Claire Legendre, Daniel Henrion, Nathalie Guérineau, Christian Legros, César Mattei, Hélène Tricoire-Leignel. Partial Agonist Activity of Neonicotinoids on Rat Nicotinic Receptors: Consequences over Epinephrine Secretion and In Vivo Blood Pressure. International Journal of Molecular Sciences. 2021; 22 (10):5106.
Chicago/Turabian StyleJoohee Park; Antoine Taly; Jennifer Bourreau; Frédéric De Nardi; Claire Legendre; Daniel Henrion; Nathalie Guérineau; Christian Legros; César Mattei; Hélène Tricoire-Leignel. 2021. "Partial Agonist Activity of Neonicotinoids on Rat Nicotinic Receptors: Consequences over Epinephrine Secretion and In Vivo Blood Pressure." International Journal of Molecular Sciences 22, no. 10: 5106.
Cardiovascular diseases (CVDs) are considered as a major cause of death worldwide. Therefore, identifying and developing therapeutic strategies to treat and reduce the prevalence of CVDs is a major medical challenge. Several drugs used for the treatment of CVDs, such as captopril, emerged from natural products, namely snake venoms. These venoms are complex mixtures of bioactive molecules, which, among other physiological networks, target the cardiovascular system, leading to them being considered in the development and design of new drugs. In this review, we describe some snake venom molecules targeting the cardiovascular system such as phospholipase A2 (PLA2), natriuretic peptides (NPs), bradykinin-potentiating peptides (BPPs), cysteine-rich secretory proteins (CRISPs), disintegrins, fibrinolytic enzymes, and three-finger toxins (3FTXs). In addition, their molecular targets, and mechanisms of action—vasorelaxation, inhibition of platelet aggregation, cardioprotective activities—are discussed. The dissection of their biological effects at the molecular scale give insights for the development of future snake venom-derived drugs.
Jacinthe Frangieh; Mohamad Rima; Ziad Fajloun; Daniel Henrion; Jean-Marc Sabatier; Christian Legros; César Mattei. Snake Venom Components: Tools and Cures to Target Cardiovascular Diseases. Molecules 2021, 26, 2223 .
AMA StyleJacinthe Frangieh, Mohamad Rima, Ziad Fajloun, Daniel Henrion, Jean-Marc Sabatier, Christian Legros, César Mattei. Snake Venom Components: Tools and Cures to Target Cardiovascular Diseases. Molecules. 2021; 26 (8):2223.
Chicago/Turabian StyleJacinthe Frangieh; Mohamad Rima; Ziad Fajloun; Daniel Henrion; Jean-Marc Sabatier; Christian Legros; César Mattei. 2021. "Snake Venom Components: Tools and Cures to Target Cardiovascular Diseases." Molecules 26, no. 8: 2223.
Anterior pituitary endocrine cells that release hormones such as growth hormone and prolactin are excitable and fire action potentials. In these cells, several studies previously showed that extracellular sodium (Na+) removal resulted in a negative shift of the resting membrane potential (RMP) and a subsequent inhibition of the spontaneous firing of action potentials, suggesting the contribution of a Na+ background conductance. Here, we show that the Na+ leak channel NALCN conducts a Ca2+‐ Gd3+‐sensitive and TTX‐resistant Na+ background conductance in the GH3 cell line, a cell model of pituitary endocrine cells. NALCN knockdown hyperpolarized the RMP, altered GH3 cell electrical properties and inhibited prolactin secretion. Conversely, the overexpression of NALCN depolarized the RMP, also reshaping the electrical properties of GH3 cells. Overall, our results indicate that NALCN is functional in GH3 cells and involved in endocrine cell excitability as well as in hormone secretion. Indeed, the GH3 cell line suitably models native pituitary cells that display a similar Na+ background conductance and appears as a proper cellular model to study the role of NALCN in cellular excitability.
Hathaichanok Impheng; Céline Lemmers; Malik Bouasse; Christian Legros; Narawut Pakaprot; Nathalie C. Guérineau; Philippe Lory; Arnaud Monteil. The sodium leak channel NALCN regulates cell excitability of pituitary endocrine cells. The FASEB Journal 2021, 35, e21400 .
AMA StyleHathaichanok Impheng, Céline Lemmers, Malik Bouasse, Christian Legros, Narawut Pakaprot, Nathalie C. Guérineau, Philippe Lory, Arnaud Monteil. The sodium leak channel NALCN regulates cell excitability of pituitary endocrine cells. The FASEB Journal. 2021; 35 (5):e21400.
Chicago/Turabian StyleHathaichanok Impheng; Céline Lemmers; Malik Bouasse; Christian Legros; Narawut Pakaprot; Nathalie C. Guérineau; Philippe Lory; Arnaud Monteil. 2021. "The sodium leak channel NALCN regulates cell excitability of pituitary endocrine cells." The FASEB Journal 35, no. 5: e21400.
Etifoxine (EFX) is a non-benzodiazepine psychoactive drug which exhibits anxiolytic effects through a dual mechanism, by directly binding to GABAA receptors (GABAARs) and to the mitochondrial 18-kDa translocator protein, resulting in the potentiation of the GABAergic function. The β subunit subtype plays a key role in the EFX-GABAAR interaction, however this does not explain the anxiolytic effects of this drug. Here, we combined behavioral and electrophysiological experiments to challenge the role of the GABAAR α subunit in the EFX mode of action. After single administrations of anxiolytic doses (25-50 mg/kg, intraperitoneal), EFX did not induce any neurological nor locomotor impairments, unlike the benzodiazepine bromazepam (0.5-1 mg/kg, intraperitoneal). We established the EFX pharmacological profile on heteropentameric GABAARs constructed with α1 to α6 subunit expressed in Xenopus oocyte. Unlike what is known for benzodiazepines, neither the γ nor δ subunits influenced EFX-mediated potentiation of GABA-evoked currents. EFX acted first as a partial agonist on α2β3γ2S, α3β3γ2S, α6β3γ2S and α6β3δ GABAARs, but not on α1β3γ2S, α4β3γ2S, α4β3δ nor α5β3γ2S GABAARs. Moreover, EFX exhibited much higher positive allosteric modulation towards α2β3γ2S, α3β3γ2S and α6β3γ2S than for α1β3γ2S, α4β3γ2S and α5β3γ2S GABAARs. At 20 µM, corresponding to brain concentration at anxiolytic doses, EFX increased GABA potency to the highest extent for α3β3γ2S GABAARs. We built a docking model of EFX on α3β3γ2S GABAARs, which is consistent with a binding site located between α and β subunits in the extracellular domain. In conclusion, EFX preferentially potentiates α2β3γ2S and α3β3γ2S GABAARs, which might support its advantageous anxiolytic/sedative balance.
César Mattei; Antoine Taly; Zineb Soualah; Ophélie Saulais; Daniel Henrion; Nathalie Guerineau; Marc Verleye; Christian Legros. Involvement of the GABAA receptor α subunit in the mode of action of etifoxine. Pharmacological Research 2019, 145, 104250 .
AMA StyleCésar Mattei, Antoine Taly, Zineb Soualah, Ophélie Saulais, Daniel Henrion, Nathalie Guerineau, Marc Verleye, Christian Legros. Involvement of the GABAA receptor α subunit in the mode of action of etifoxine. Pharmacological Research. 2019; 145 ():104250.
Chicago/Turabian StyleCésar Mattei; Antoine Taly; Zineb Soualah; Ophélie Saulais; Daniel Henrion; Nathalie Guerineau; Marc Verleye; Christian Legros. 2019. "Involvement of the GABAA receptor α subunit in the mode of action of etifoxine." Pharmacological Research 145, no. : 104250.
Bee venom is a mixture of several components with proven therapeutic benefits, among which are anti-inflammatory, analgesic, and various cardiovascular conditions. In this work, we analyzed for the first time the proteomic content and biological properties of the crude venom from Apis mellifera syriaca, a honeybee from the Middle East region. Using high-performance liquid chromatography-tandem mass spectrometry, we evidence the venom contains phospholipase A2, hyaluronidase, mast cell-degranulating peptide, adolapin, apamin, and melittin. The latter was purified by solid phase extraction method (SPE) and tested in parallel with crude venom for biological activities. Precisely, crude venom-but not melittin-exhibited antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa strains. Alongside, hemolytic activity was observed in human blood subjected to the venom at high doses. A. mellifera syriaca venom displayed antioxidant activities, and not surprisingly, PLA2 catalytic activity. Eventually, the venom proved to exert antiproliferative effects against MCF-7 and 3T3 cancer cells lines. This first report of a new bee venom opens new avenues for therapeutic uses of bee venoms.
Jacinthe Frangieh; Yahya Salma; Katia Haddad; Cesar Mattei; Christian Legros; Ziad Fajloun; Dany El Obeid. First Characterization of The Venom from Apis mellifera syriaca, A Honeybee from The Middle East Region. Toxins 2019, 11, 191 .
AMA StyleJacinthe Frangieh, Yahya Salma, Katia Haddad, Cesar Mattei, Christian Legros, Ziad Fajloun, Dany El Obeid. First Characterization of The Venom from Apis mellifera syriaca, A Honeybee from The Middle East Region. Toxins. 2019; 11 (4):191.
Chicago/Turabian StyleJacinthe Frangieh; Yahya Salma; Katia Haddad; Cesar Mattei; Christian Legros; Ziad Fajloun; Dany El Obeid. 2019. "First Characterization of The Venom from Apis mellifera syriaca, A Honeybee from The Middle East Region." Toxins 11, no. 4: 191.
Objective: Sympathetic hyperactivation, a common feature of obesity and metabolic syndrome, is a key trigger of hypertension. However, some obese subjects with autonomic unbalance present a dissociation between sympathetic activity mediated vasoconstriction and increased blood pressure. Here, we aimed to determine in a rat model of metabolic syndrome, whether the endothelium eNOS-NO pathway contribute to counteract the vasopressor effect of the sympathetic system. Methods: Rats were fed a high fat and high sucrose diet for 15 weeks (HFS). Sympatho-vagal balance was evaluated by spectral analysis of heart rate variability and plasmatic catecholamines measurements. Blood pressure was measured in presence or not of L-NAME to inhibit the contribution of eNOS. Vascular reactivity was assessed on isolated aortic rings in response to α1-adrenergic agonist. Results: HFS diet increased sympathetic tone, which is characterized by higher low on high-frequency spectral power ratio and higher plasmatic concentration of epinephrine. Despite this, no change in blood pressure was observed. Interestingly, HFS rats exhibited vascular hyporeactivity (-23.6%) to α1-adrenergic receptors stimulation that was abolished by endothelial removing or eNOS inhibition (L-NAME). In addition, eNOS phosphorylation (ser1177) was increased in response to phenylephrine in HFS rats only. Accordingly, eNOS inhibition in-vivo revealed higher blood pressure in HFS compared to control rats (Respectively 147 vs 126 mmHg for mean blood pressure). Conclusion: Restrain of adrenergic vasopressor action by the endothelium eNOS is increased in HFS rats and contributes to maintain blood pressure in physiological range.
Sylvain Battault; Cindy Meziat; Alessandro R Nascimento; Laura Braud; Sandrine Gayrard; Christian Legros; Frederic De Nardi; Jocelyne Drai; Olivier Cazorla; Jérôme Thireau; Gregory Meyer; Cyril Reboul. Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome. American Journal of Physiology-Heart and Circulatory Physiology 2018, 314, H497 -H507.
AMA StyleSylvain Battault, Cindy Meziat, Alessandro R Nascimento, Laura Braud, Sandrine Gayrard, Christian Legros, Frederic De Nardi, Jocelyne Drai, Olivier Cazorla, Jérôme Thireau, Gregory Meyer, Cyril Reboul. Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome. American Journal of Physiology-Heart and Circulatory Physiology. 2018; 314 (3):H497-H507.
Chicago/Turabian StyleSylvain Battault; Cindy Meziat; Alessandro R Nascimento; Laura Braud; Sandrine Gayrard; Christian Legros; Frederic De Nardi; Jocelyne Drai; Olivier Cazorla; Jérôme Thireau; Gregory Meyer; Cyril Reboul. 2018. "Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome." American Journal of Physiology-Heart and Circulatory Physiology 314, no. 3: H497-H507.
Catecholamine secretion from the adrenal medullary tissue is a key step of the adaptive response triggered by an organism to cope with stress. Whereas molecular and cellular secretory processes have been extensively studied at the single chromaffin cell level, data available for the whole gland level are much scarcer. We tackled this issue in rat by developing an easy to implement experimental strategy combining the adrenal acute slice supernatant collection with a high performance liquid chromatography-based epinephrine and norepinephrine assay. This technique affords a convenient method for measuring basal and stimulated catecholamine release from single acute slices, allowing thus to individually address the secretory function of the left and right glands. Our data point that the two glands are equally competent to secrete epinephrine and norepinephrine, exhibiting an equivalent epinephrine:norepinephrine ratio, both at rest and in response to a cholinergic stimulation. Nicotine is however more efficient than acetylcholine to evoke norepinephrine release. A pharmacological challenge with hexamethonium, an α3-containing nicotinic acetylcholine receptor antagonist, disclosed that epinephrine- and norepinephrine-secreting chromaffin cells distinctly expressed α3 nicotinic receptors, with a dominant contribution in norepinephrine cells. As such, beyond the novelty of catecholamine assays from acute slice supernatants, our study contributes at refining the secretory behavior of the rat adrenal medullary tissue, and opens new perspectives for monitoring the release of other hormones and transmitters, especially those involved in the stress response.
Frédéric De Nardi; Claudie Lefort; Dimitri Bréard; Pascal Richomme; Christian Legros; Nathalie C. Guérineau. Monitoring the Secretory Behavior of the Rat Adrenal Medulla by High-Performance Liquid Chromatography-Based Catecholamine Assay from Slice Supernatants. Frontiers in Endocrinology 2017, 8, 248 .
AMA StyleFrédéric De Nardi, Claudie Lefort, Dimitri Bréard, Pascal Richomme, Christian Legros, Nathalie C. Guérineau. Monitoring the Secretory Behavior of the Rat Adrenal Medulla by High-Performance Liquid Chromatography-Based Catecholamine Assay from Slice Supernatants. Frontiers in Endocrinology. 2017; 8 ():248.
Chicago/Turabian StyleFrédéric De Nardi; Claudie Lefort; Dimitri Bréard; Pascal Richomme; Christian Legros; Nathalie C. Guérineau. 2017. "Monitoring the Secretory Behavior of the Rat Adrenal Medulla by High-Performance Liquid Chromatography-Based Catecholamine Assay from Slice Supernatants." Frontiers in Endocrinology 8, no. : 248.
Sylvain Battault; Cindy Meziat; Alessandro Nascimento; Laura Braud; Julien Peyrol; Sandrine Gayrard; Jocelyne Drai; Christian Legros; Frédéric De Nardi; Olivier Cazorla; Jérôme Thireau; Grégory Meyer; Cyril Reboul. 0093 : Endothelium masks increased sympathetic vasopressor activity in rats with metabolic syndrome. Archives of Cardiovascular Diseases Supplements 2016, 8, 248 .
AMA StyleSylvain Battault, Cindy Meziat, Alessandro Nascimento, Laura Braud, Julien Peyrol, Sandrine Gayrard, Jocelyne Drai, Christian Legros, Frédéric De Nardi, Olivier Cazorla, Jérôme Thireau, Grégory Meyer, Cyril Reboul. 0093 : Endothelium masks increased sympathetic vasopressor activity in rats with metabolic syndrome. Archives of Cardiovascular Diseases Supplements. 2016; 8 (3):248.
Chicago/Turabian StyleSylvain Battault; Cindy Meziat; Alessandro Nascimento; Laura Braud; Julien Peyrol; Sandrine Gayrard; Jocelyne Drai; Christian Legros; Frédéric De Nardi; Olivier Cazorla; Jérôme Thireau; Grégory Meyer; Cyril Reboul. 2016. "0093 : Endothelium masks increased sympathetic vasopressor activity in rats with metabolic syndrome." Archives of Cardiovascular Diseases Supplements 8, no. 3: 248.
Highlights•TipE homologous genes form a highly conserved auxiliary subunits subfamily in insects.•TipE homolog from P. americana acts as a strong expression stimulator on DmNav channels in Xenopus oocytes.•The insect Nav auxiliary subunits share functional features with their mammalian counterparts, although they are structurally and phylogenetically distant. AbstractIn Drosophila melanogaster, the functions of voltage-gated sodium (Nav) channels are modulated by TipE and its orthologs. Here, we describe a novel TipE homolog of the American cockroach, Periplaneta americana, called PaTipE. Like DmTipE, PaTipE mRNAs are ubiquitously expressed. Surprisingly, PaTipE mRNA was undetectable in neurosecretory cells identified as dorsal unpaired median neurons. Phylogenetic analysis placed this new sequence in TipE clade, indicating an independent evolution from a common ancestor. Contrary to previous reports, our data indicate that the auxiliary subunits of insect Nav channels are very distant from the mammalian BKCa auxiliary subunits. To decipher the functional roles of PaTipE, we characterized the gating properties of DmNav1-1 channels co-expressed with DmTipE or PaTipE, in Xenopus oocytes. Compared to DmTipE, PaTipE increased Na+ currents by a 4.2-fold. The voltage-dependence of steady-state fast inactivation of DmNav1-1/PaTipE channels was shifted by 5.8 mV to more negative potentials than that of DmNav1-1/DmTipE channels. DmNav1-1/PaTipE channels recovered 3.2-fold slower from the fast-inactivated state than DmNav1-1/DmTipE channels. In conclusion, this study supports that the insect Nav auxiliary subunits share functional features with their mammalian counterparts, although structurally and phylogenetically distant. Graphical abstract
Céline M. Bourdin; Nathalie C. Guerineau; Laurence Murillo; Sophie Quinchard; Ke Dong; Christian Legros. Molecular and functional characterization of a novel sodium channel TipE-like auxiliary subunit from the American cockroach Periplaneta americana. Insect Biochemistry and Molecular Biology 2015, 66, 136 -144.
AMA StyleCéline M. Bourdin, Nathalie C. Guerineau, Laurence Murillo, Sophie Quinchard, Ke Dong, Christian Legros. Molecular and functional characterization of a novel sodium channel TipE-like auxiliary subunit from the American cockroach Periplaneta americana. Insect Biochemistry and Molecular Biology. 2015; 66 ():136-144.
Chicago/Turabian StyleCéline M. Bourdin; Nathalie C. Guerineau; Laurence Murillo; Sophie Quinchard; Ke Dong; Christian Legros. 2015. "Molecular and functional characterization of a novel sodium channel TipE-like auxiliary subunit from the American cockroach Periplaneta americana." Insect Biochemistry and Molecular Biology 66, no. : 136-144.
Voltage-gated sodium channels (Nav) are key components for nerve excitability. They initiate and propagate the action potential in excitable cells, throughout the central and peripheral nervous system, thus enabling a variety of physiological functions to be achieved. The rising phase of the action potential is driven by the opening of Nav channels which activate rapidly and carry Na(+) ions in the intracellular medium, and ends with the Na(+) current inactivation. The biophysical properties of these channels have been elucidated, through the use of pharmacological agents that disrupt the molecular mechanism of the channel functioning. Among them, marine toxins produced by venomous animals or microorganisms have been crucial to map the different allosteric binding sites of the channels, understand their mode of action and represent an emerging source of therapeutic agents to alleviate or cure Na(+) channels-linked human diseases. In this article, we review recent discoveries on the molecular and biophysical properties of the Na(+) channel as a target for marine neurotoxins, and present the ongoing developments of pharmacological agents as therapeutic tools.
César Mattei; Christian Legros. The voltage-gated sodium channel: A major target of marine neurotoxins. Toxicon 2014, 91, 84 -95.
AMA StyleCésar Mattei, Christian Legros. The voltage-gated sodium channel: A major target of marine neurotoxins. Toxicon. 2014; 91 ():84-95.
Chicago/Turabian StyleCésar Mattei; Christian Legros. 2014. "The voltage-gated sodium channel: A major target of marine neurotoxins." Toxicon 91, no. : 84-95.
Insect voltage-gated sodium (Nav) channels are formed by a well-known pore-forming α-subunit encoded by para-like gene and ancillary subunits related to TipE from the mutation “temperature-induced-paralysis locus E.” The role of these ancillary subunits in the modulation of biophysical and pharmacological properties of Na+ currents are not enough documented. The unique neuronal ancillary subunit TipE-homologous protein 1 of Drosophila melanogaster (DmTEH1) strongly enhances the expression of insect Nav channels when heterologously expressed in Xenopus oocytes. Here we report the cloning and functional expression of two neuronal DmTEH1-homologs of the cockroach, Periplaneta americana, PaTEH1A and PaTEH1B, encoded by a single bicistronic gene. In PaTEH1B, the second exon encoding the last 11-amino-acid residues of PaTEH1A is shifted to 3′UTR by the retention of a 96-bp intron-containing coding-message, thus generating a new C-terminal end. We investigated the gating and pharmacological properties of the Drosophila Nav channel variant (DmNav1-1) co-expressed with DmTEH1, PaTEH1A, PaTEH1B or a truncated mutant PaTEH1Δ(270-280) in Xenopus oocytes. PaTEH1B caused a 2.2-fold current density decrease, concomitant with an equivalent α-subunit incorporation decrease in the plasma membrane, compared to PaTEH1A and PaTEH1Δ(270-280). PaTEH1B positively shifted the voltage-dependences of activation and slow inactivation of DmNav1-1 channels to more positive potentials compared to PaTEH1A, suggesting that the C-terminal end of both proteins may influence the function of the voltage-sensor and the pore of Nav channel. Interestingly, our findings showed that the sensitivity of DmNav1-1 channels to lidocaine and to the pyrazoline-type insecticide metabolite DCJW depends on associated TEH1-like subunits. In conclusion, our work demonstrates for the first time that density, gating and pharmacological properties of Nav channels expressed in Xenopus oocytes can be modulated by an intron retention process in the transcription of the neuronal TEH1-like ancillary subunits of P. americana.
Céline M. Bourdin; Bénédicte Moignot; Lingxin Wang; Laurence Murillo; Marjorie Juchaux; Sophie Quinchard; Bruno Lapied; Nathalie Guerineau; Ke Dong; Christian Legros. Intron Retention in mRNA Encoding Ancillary Subunit of Insect Voltage-Gated Sodium Channel Modulates Channel Expression, Gating Regulation and Drug Sensitivity. PLOS ONE 2013, 8, e67290 .
AMA StyleCéline M. Bourdin, Bénédicte Moignot, Lingxin Wang, Laurence Murillo, Marjorie Juchaux, Sophie Quinchard, Bruno Lapied, Nathalie Guerineau, Ke Dong, Christian Legros. Intron Retention in mRNA Encoding Ancillary Subunit of Insect Voltage-Gated Sodium Channel Modulates Channel Expression, Gating Regulation and Drug Sensitivity. PLOS ONE. 2013; 8 (8):e67290.
Chicago/Turabian StyleCéline M. Bourdin; Bénédicte Moignot; Lingxin Wang; Laurence Murillo; Marjorie Juchaux; Sophie Quinchard; Bruno Lapied; Nathalie Guerineau; Ke Dong; Christian Legros. 2013. "Intron Retention in mRNA Encoding Ancillary Subunit of Insect Voltage-Gated Sodium Channel Modulates Channel Expression, Gating Regulation and Drug Sensitivity." PLOS ONE 8, no. 8: e67290.
Calcium/calmodulin-dependent protein kinase II (CaMKII) is a key kinase that transduces Ca²⁺ signals into downstream effects acting on a range of cellular processes in nervous system and muscular tissues. In insects, different CaMKII isoforms have been reported in Drosophila melanogaster, Apis florae, Bombus terrestris, and Bombus impatiens but little is known on the organization and tissue-specific expression of these isoforms with the exception of Drosophila. The present study reports the cloning of five CaMKII splice variants issued from a single gene and their tissue-specific expression in the cockroach Periplaneta americana. Each CaMKII isoform shared 82-90% identity with Drosophila CaMKII isoforms and accordingly were named PaCaMKII-A, PaCaMKII-B,PaCaMKII-C,PaCaMKII-D, and PaCaMKII-E. PaCaMKII-A and PaCaMKII-D isoforms are ubiquitously expressed in all tissues, but some such as PaCaMKII-B andPaCaMKII-C are preferentially expressed in the nerve cord and muscle. In addition, using single-cell reverse transcriptase-polymerase chain reaction (RT-PCR), we found a tissue-specific expression of PaCaMKII-E in the dorsal unpaired median neurons. Alternative splicing of PaCaMKII transcripts is likely a common mechanism in insects to control the pattern of isoform expression in the different tissues.
Emiliane Taillebois; Emilie Heuland; Céline M. Bourdin; Audrey Griveau; Sophie Quinchard; Helene Tricoire-Leignel; Christian Legros; Steeve H. Thany. Ca2+/CALMODULIN-DEPENDENT PROTEIN KINASE II IN THE COCKROACHPeriplaneta americana: IDENTIFICATION OF FIVE ISOFORMS AND THEIR TISSUES DISTRIBUTION. Archives of Insect Biochemistry and Physiology 2013, 83, 138 -150.
AMA StyleEmiliane Taillebois, Emilie Heuland, Céline M. Bourdin, Audrey Griveau, Sophie Quinchard, Helene Tricoire-Leignel, Christian Legros, Steeve H. Thany. Ca2+/CALMODULIN-DEPENDENT PROTEIN KINASE II IN THE COCKROACHPeriplaneta americana: IDENTIFICATION OF FIVE ISOFORMS AND THEIR TISSUES DISTRIBUTION. Archives of Insect Biochemistry and Physiology. 2013; 83 (3):138-150.
Chicago/Turabian StyleEmiliane Taillebois; Emilie Heuland; Céline M. Bourdin; Audrey Griveau; Sophie Quinchard; Helene Tricoire-Leignel; Christian Legros; Steeve H. Thany. 2013. "Ca2+/CALMODULIN-DEPENDENT PROTEIN KINASE II IN THE COCKROACHPeriplaneta americana: IDENTIFICATION OF FIVE ISOFORMS AND THEIR TISSUES DISTRIBUTION." Archives of Insect Biochemistry and Physiology 83, no. 3: 138-150.
Octopamine (OA) is an important neuroactive substance that modulates several physiological functions and behaviors of various invertebrate species. This biogenic monoamine, structurally related to noradrenaline, acts as a neurotransmitter, a neuromodulator, or a neurohormone in insects. The tyramine β-hydroxylase (TBH) catalyzes the last step in OA biosynthesis and thus plays a key role in the regulation of synthesis and secretion of OA in neurons. The aim of this study was to characterize TBH in the cockroach Periplaneta americana and to get a better understanding of its regulation under stress conditions in this insect. First of all, five full-length cDNAs encoding TBH isoforms were cloned from the nerve cord of the physiological model P. americana. PaTBH transcripts were found mainly expressed in nervous tissues and in octopaminergic dorsal unpaired median neurons. In addition, a new ELISA assay was developed so as to allow determination of both OA level and TBH activity in stressed cockroaches. Mechanical stressful stimulation led to a significant increase in TBH activity after 1 and 24 h, with a higher induction after 1 h than after 24 h. Thus, TBH could be considered as a promising biomarker of stress in insects rather than OA. Octopamine (OA) is an important neuroactive substance that modulates several physiological functions and behaviors of various invertebrate species. This biogenic monoamine, structurally related to noradrenaline, acts as a neurotransmitter, a neuromodulator, or a neurohormone in insects. The tyramine β-hydroxylase (TBH) catalyzes the last step in OA biosynthesis and thus plays a key role in the regulation of synthesis and secretion of OA in neurons. The aim of this study was to characterize TBH in the cockroach Periplaneta americana and to get a better understanding of its regulation under stress conditions in this insect. First of all, five full-length cDNAs encoding TBH isoforms were cloned from the nerve cord of the physiological model P. americana. PaTBH transcripts were found mainly expressed in nervous tissues and in octopaminergic dorsal unpaired median neurons. In addition, a new ELISA assay was developed so as to allow determination of both OA level and TBH activity in stressed cockroaches. Mechanical stressful stimulation led to a significant increase in TBH activity after 1 and 24 h, with a higher induction after 1 h than after 24 h. Thus, TBH could be considered as a promising biomarker of stress in insects rather than OA.
Amélie Châtel; Laurence Murillo; Céline Michelle Bourdin; Sophie Quinchard; Damien Picard; Christian Legros. Characterization of tyramine -hydroxylase, an enzyme upregulated by stress in Periplaneta americana. Journal of Molecular Endocrinology 2012, 50, 91 -102.
AMA StyleAmélie Châtel, Laurence Murillo, Céline Michelle Bourdin, Sophie Quinchard, Damien Picard, Christian Legros. Characterization of tyramine -hydroxylase, an enzyme upregulated by stress in Periplaneta americana. Journal of Molecular Endocrinology. 2012; 50 (1):91-102.
Chicago/Turabian StyleAmélie Châtel; Laurence Murillo; Céline Michelle Bourdin; Sophie Quinchard; Damien Picard; Christian Legros. 2012. "Characterization of tyramine -hydroxylase, an enzyme upregulated by stress in Periplaneta americana." Journal of Molecular Endocrinology 50, no. 1: 91-102.
The French Ion Channel society has existed since 1989 and its main goal is to annually organize a scientific meeting. This meeting, which gathers young and senior French scientists, provides a great opportunity for exchange and interaction among the ion channel research community. Additionally, for many years, the French ion channel meeting has attracted a significant number of scientists from different European countries, promoting the discussion of new insights and advances, as well as aiding in the establishment of collaborations. In this report, we summarize the five symposia selected for their novelty and importance in human channelopathies, neuroplasticity, ion channel regulations, intracellular ion channels and plant physiology.
Sophie Nicole; Jean-Luc Morel; Sébastien Roger; Anne-Aliénor Véry; Hélène Vacher; Christian Legros. The 20th ion channel meeting: September 2009, France. Channels 2010, 4, 329 -333.
AMA StyleSophie Nicole, Jean-Luc Morel, Sébastien Roger, Anne-Aliénor Véry, Hélène Vacher, Christian Legros. The 20th ion channel meeting: September 2009, France. Channels. 2010; 4 (4):329-333.
Chicago/Turabian StyleSophie Nicole; Jean-Luc Morel; Sébastien Roger; Anne-Aliénor Véry; Hélène Vacher; Christian Legros. 2010. "The 20th ion channel meeting: September 2009, France." Channels 4, no. 4: 329-333.
Voltage-gated sodium channels (Nav channels) belong to a superfamily of ion channels which play an essential role in membrane excitability. Only one gene encoding Nav channels has been characterized so far in insects. Here, we have cloned one full-length cDNA encoding a conventional insect Nav channel (PaNav1) and two full-length cDNAs encoding putative insect Nav channels (PaFPC1 and PaFPC2) in Periplaneta americana, a model insect for neurophysiological studies. The ORFs of PaFPC1 and PaFPC2 contained 4662 bp and encoded 1553 amino acid residues, and the ORF of PaNav1 contained 6153 bp and encoded 2051 amino acid residues. PaFPC1 and PaFPC2 are two isoforms, which differ by eight single amino acid substitutions. PaFPC1 shares 37.5–55% protein identities with known insect Nav channels, while PaNav1 shares 70–97.5% protein identities with these latter. Both PaFPC1 and PaFPC2 possess the molecular hallmarks of Nav channels except the motif involved in fast inactivation. Contrary to PaNav1 transcripts which are expressed mainly in the central nervous system, those ones of PaFPC are also expressed in non-neuronal tissues (muscles, gut and mushroom-shaped accessory glands). A detailed phylogenetic analysis confirmed that PaNav1 and PaFPC are evolutionarily closely related to insect Nav channel genes.
Bénédicte Moignot; Christophe Lemaire; Sophie Quinchard; Bruno Lapied; Christian Legros. The discovery of a novel sodium channel in the cockroach Periplaneta americana: Evidence for an early duplication of the para-like gene. Insect Biochemistry and Molecular Biology 2009, 39, 814 -823.
AMA StyleBénédicte Moignot, Christophe Lemaire, Sophie Quinchard, Bruno Lapied, Christian Legros. The discovery of a novel sodium channel in the cockroach Periplaneta americana: Evidence for an early duplication of the para-like gene. Insect Biochemistry and Molecular Biology. 2009; 39 (11):814-823.
Chicago/Turabian StyleBénédicte Moignot; Christophe Lemaire; Sophie Quinchard; Bruno Lapied; Christian Legros. 2009. "The discovery of a novel sodium channel in the cockroach Periplaneta americana: Evidence for an early duplication of the para-like gene." Insect Biochemistry and Molecular Biology 39, no. 11: 814-823.
In this study, we have characterized the immunological and pharmacological properties of the three major α-type toxins from the scorpion Androctonus amoreuxi, AamH1, AamH2 and AamH3, which were previously described as putative toxins from cDNAs [Chen, T. et al., 2003. Regul. Pept. 115, 115–121]. The immunological tests (ELISA, RIA) have demonstrated that AamH1, AamH2 and AamH3 belong to the immunological groups 3 and 4 of α-type toxins. Analysis of the three toxin effects on currents through rat brain (rNav1.2), rat muscle (rNav1.4) and Drosophila (DmNav1) sodium channels expressed in Xenopus oocytes revealed that AamH1 and AamH2, but not AamH3, have anti-insect and anti-mammal activities and can be classified as α-like toxins. While AamH1 removes fast inactivation only in neuronal rNav1.2 channel and has no effect on muscular rNav1.4 channel, AamH2 affects both neuronal rNav1.2 and muscular rNav1.4 channels. AamH3 was lethal to mice by intracerebroventricular injection despite its lack of activity on the neuronal rNav1.2 channel. Finally, we have shown that the A. amoreuxi venom was better neutralized by the antiserum raised against the venom of Buthus occitanus tunetanus than by the antisera raised against scorpion venoms from the same genus Androctonus.
Najwa Abbas; Christian Legros; Brigitte Céard; Maya Belghazi; Alain Hamon; Pierre E. Bougis; Marie-France Martin-Eauclaire. Full characterization of three toxins from the Androctonus amoreuxi scorpion venom. Toxicon 2009, 54, 460 -470.
AMA StyleNajwa Abbas, Christian Legros, Brigitte Céard, Maya Belghazi, Alain Hamon, Pierre E. Bougis, Marie-France Martin-Eauclaire. Full characterization of three toxins from the Androctonus amoreuxi scorpion venom. Toxicon. 2009; 54 (4):460-470.
Chicago/Turabian StyleNajwa Abbas; Christian Legros; Brigitte Céard; Maya Belghazi; Alain Hamon; Pierre E. Bougis; Marie-France Martin-Eauclaire. 2009. "Full characterization of three toxins from the Androctonus amoreuxi scorpion venom." Toxicon 54, no. 4: 460-470.
International audienceThe 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
Christian Legros; Catherine Guette; Max Goyffon; Jeanine Tortajada; Marie-France Martin-Eauclaire. 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 Communications in Mass Spectrometry 2009, 23, 745 -755.
AMA StyleChristian Legros, Catherine Guette, Max Goyffon, Jeanine Tortajada, Marie-France Martin-Eauclaire. 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 Communications in Mass Spectrometry. 2009; 23 (6):745-755.
Chicago/Turabian StyleChristian Legros; Catherine Guette; Max Goyffon; Jeanine Tortajada; Marie-France Martin-Eauclaire. 2009. "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 Communications in Mass Spectrometry 23, no. 6: 745-755.
A recombinant peptidic spider toxin, HpTx2, was investigated directly by nanoelectrospray tandem mass spectrometry (MS/MS). This 30-residue toxin possesses a highly knotted structure with cystines arranged in close proximity. The low-energy collision-induced dissociation MS/MS spectrum of the [M+4H](4+) ion permitted characterization of the C-terminal sequence of HpTx2 up to Cys(26) that is involved in a disulfide bridge. Chemical pre-treatment with DTT or TCEP was then investigated, and it was found that an unexpected cleavage reaction of HpTx2 gave two smaller peptides which were completely sequenced by MS/MS experiments using a Qq-TOF mass spectrometer. This unusual hydrolysis reaction facilitated the determination of the complete sequence of the HpTx2 toxin.
Christian Legros; Marie-Louise Célérier; Catherine Guette. An unusual cleavage reaction of a peptide observed during dithiotreitol and tris(2-carboxyethyl)phosphine reduction: application to sequencing of HpTx2 spider toxin using nanospray tandem mass spectrometry. Rapid Communications in Mass Spectrometry 2004, 18, 1317 -1323.
AMA StyleChristian Legros, Marie-Louise Célérier, Catherine Guette. An unusual cleavage reaction of a peptide observed during dithiotreitol and tris(2-carboxyethyl)phosphine reduction: application to sequencing of HpTx2 spider toxin using nanospray tandem mass spectrometry. Rapid Communications in Mass Spectrometry. 2004; 18 (12):1317-1323.
Chicago/Turabian StyleChristian Legros; Marie-Louise Célérier; Catherine Guette. 2004. "An unusual cleavage reaction of a peptide observed during dithiotreitol and tris(2-carboxyethyl)phosphine reduction: application to sequencing of HpTx2 spider toxin using nanospray tandem mass spectrometry." Rapid Communications in Mass Spectrometry 18, no. 12: 1317-1323.