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Price KL, Lummis SCR. Characterisation of thymol effects on RDL receptors from the bee parasite Varroa destructor. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 183:105064. [PMID: 35430066 DOI: 10.1016/j.pestbp.2022.105064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
A major contributor to bee colony decline is infestation with its most devastating pest, the mite Varroa destructor. To control these mites, thymol is often used, although how it achieves this is not understood. One well-documented action of thymol is to modulate GABA-activated ion channels, which includes insect RDL receptors, a known insecticidal target. Here we have cloned two Varroa RDL subunits, one of which is similar to the canonical RDL subunit, while the other has some differences in M4, and, to a lesser extent, M2 and its binding site loops. Expression of this unusual RDL receptor in Xenopus oocytes reveals GABA-activated receptors, with an EC50 of 56 μM. In contrast to canonical RDL receptors, thymol does not enhance GABA-elicited responses in this receptor, and concentration response curves reveal a decrease in GABA Imax in its presence; this decrease is not seen when similar data are obtained from Apis RDL receptors. We conclude that an M2 T6'M substitution is primarily responsible for the different thymol effects, and suggest that understanding how and where thymol acts could assist in the design of novel bee-friendly miticides.
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Affiliation(s)
- K L Price
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - S C R Lummis
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK.
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2
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Cens T, Chavanieu A, Bertaud A, Mokrane N, Estaran S, Roussel J, Ménard C, De Jesus Ferreira M, Guiramand J, Thibaud J, Cohen‐Solal C, Rousset M, Rolland V, Vignes M, Charnet P. Molecular Targets of Neurotoxic Insecticides in
Apis mellifera. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Thierry Cens
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Alain Chavanieu
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Anaïs Bertaud
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Nawfel Mokrane
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Sébastien Estaran
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Julien Roussel
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Claudine Ménard
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | | | - Janique Guiramand
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Jean‐Baptiste Thibaud
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Catherine Cohen‐Solal
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Matthieu Rousset
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Valérie Rolland
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Michel Vignes
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
| | - Pierre Charnet
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM 1919 Route de Mende 34293 Montpellier France
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Bertaud A, Cens T, Mary R, Rousset M, Arel E, Thibaud JB, Vignes M, Ménard C, Dutertre S, Collet C, Charnet P. Xenopus Oocytes: A Tool to Decipher Molecular Specificity of Insecticides towards Mammalian and Insect GABA—A Receptors. MEMBRANES 2022; 12:membranes12050440. [PMID: 35629767 PMCID: PMC9146934 DOI: 10.3390/membranes12050440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/09/2022] [Accepted: 04/11/2022] [Indexed: 11/16/2022]
Abstract
The number of insect GABA receptors (GABAr) available for expression studies has been recently increased by the cloning of the Acyrthosiphon pisum (pea aphid) RDL subunits. This large number of cloned RDL subunits from pest and beneficial insects opens the door to parallel pharmacological studies on the sensitivity of these different insect GABAr to various agonists or antagonists. The resulting analysis of the molecular basis of the species-specific GABAr responses to insecticides is necessary not only to depict and understand species toxicity, but also to help at the early identification of unacceptable toxicity of insecticides toward beneficial insects such as Apis mellifera (honeybees). Using heterologous expression in Xenopus laevis oocytes, and two-electrode voltage-clamp recording to assess the properties of the GABAr, we performed a comparative analysis of the pharmacological sensitivity of RDL subunits from A. pisum, A. mellifera and Varroa destructor GABAr to three pesticides (fipronil, picrotoxin and dieldrin). These data were compared to similar characterizations performed on two Homo sapiens GABA-A receptors (α2β2γ2 and α2β2γ2). Our results underline a global conservation of the pharmacological profiles of these receptors, with some interesting species specificities, nonetheless, and suggest that this approach can be useful for the early identification of poorly specific molecules.
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Affiliation(s)
- Anaïs Bertaud
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Thierry Cens
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Rosanna Mary
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Matthieu Rousset
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Elodie Arel
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Jean-Baptiste Thibaud
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Michel Vignes
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Claudine Ménard
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Sébastien Dutertre
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
| | - Claude Collet
- INRAE, UR 406, Abeilles et Environnement, Domaine St. Paul, Site Agroparc, 84140 Avignon, France;
| | - Pierre Charnet
- IBMM, UMR 5247 CNRS, Université de Montpellier, ENSCM, 1919 Route de Mende, 34293 Montpellier, France; (A.B.); (T.C.); (R.M.); (M.R.); (E.A.); (J.-B.T.); (M.V.); (C.M.); (S.D.)
- Correspondence:
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Hawkins J, Mitchell EL, Jones AK. NACHO permits functional heterologous expression of an insect homomeric α6 nicotinic acetylcholine receptor. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 181:105030. [PMID: 35082026 DOI: 10.1016/j.pestbp.2021.105030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/21/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Insect nicotinic acetylcholine receptors (nAChR) are molecular targets of highly effective insecticides. The use of chaperone proteins has been key to successful functional expression of these receptors in heterologous systems, permitting functional and pharmacological studies of insect nAChRs with particular subunit composition. Here, we report the first use of the chaperone protein, NACHO, to enable functional expression of an insect nAChR, the α6 subunit from Apis mellifera, in Xenopus laevis oocytes. This is also the first report of functional expression of a homomeric insect α6 nAChR. Using two-electrode voltage-clamp electrophysiology we show that the acetylcholine EC50 of the α6 receptor is 0.88 μM and that acetylcholine responses are antagonized by α-bungarotoxin. Spinosad showed agonist actions and kept the ion channel open when co-applied with acetylcholine, reinforcing the α6 nAChR subunit as a key molecular target for the spinosyn class of insecticide. The use of NACHO may provide a basis for future expression studies of insect α6 nAChRs, potentially providing a tool for the discovery of novel insecticides.
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Affiliation(s)
- Joseph Hawkins
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom.
| | - Eleanor L Mitchell
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom.
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom.
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Huang QT, Sheng CW, Jones AK, Jiang J, Tang T, Han ZJ, Zhao CQ. Functional Characteristics of the Lepidopteran Ionotropic GABA Receptor 8916 Subunit Interacting with the LCCH3 or the RDL Subunit. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11582-11591. [PMID: 34555899 DOI: 10.1021/acs.jafc.1c00385] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The ionotropic γ-aminobutyric acid (iGABA) receptor is commonly considered as a fast inhibitory channel and is an important insecticide target. Since 1990, RDL, LCCH3, and GRD have been successively isolated and found to be potential subunits of the insect iGABA receptor. More recently, one orphan gene named 8916 was found and considered to be another potential iGABA receptor subunit according to its amino acid sequence. However, little information about 8916 has been reported. Here, the 8916 subunit from Chilo suppressalis was studied to determine whether it can form part of a functional iGABA receptor by co-expressing this subunit with CsRDL1 or CsLCCH3 in the Xenopus oocyte system. Cs8916 or CsLCCH3 did not form functional ion channels when expressed alone. However, Cs8916 was able to form heteromeric ion channels when expressed with either CsLCCH3 or CsRDL1. The recombinant heteromeric Cs8916/LCCH3 channel was a cation-selective channel, which was sensitive to GABA or β-alanine. The current of the Cs8916/LCCH3 channel was inhibited by dieldrin, endosulfan, fipronil, or ethiprole. In contrast, fluralaner, broflanilide, and avermectin showed little effect on the Cs8916/LCCH3 channel (IC50s > 10 000 nM). The Cs8916/RDL1 channel was sensitive to GABA, but was significantly different in EC50 and Imax for GABA to those of homomeric CsRDL1. Fluralaner, fipronil, or dieldrin showed antagonistic actions on Cs8916/RDL1. In conclusion, Cs8916 is a potential iGABA receptor subunit, which can interact with CsLCCH3 to generate a cation-selective channel that is sensitive to several insecticides. Also, as Cs8916/RDL1 has a higher EC50 than homomeric CsRDL1, Cs8916 may affect the physiological functions of CsRDL1 and therefore play a role in fine-tuning GABAergic signaling.
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Affiliation(s)
- Qiu Tang Huang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Cheng Wang Sheng
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, U.K
| | - Jie Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha 410125, P. R. China
| | - Zhao Jun Han
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Chun Qing Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
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6
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Cartereau A, Taillebois E, Le Questel JY, Thany SH. Mode of Action of Neonicotinoid Insecticides Imidacloprid and Thiacloprid to the Cockroach Pameα7 Nicotinic Acetylcholine Receptor. Int J Mol Sci 2021; 22:9880. [PMID: 34576043 PMCID: PMC8471617 DOI: 10.3390/ijms22189880] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/01/2021] [Accepted: 09/08/2021] [Indexed: 12/28/2022] Open
Abstract
The functional expression of the cockroach Pameα7 nicotinic acetylcholine receptor subunit has been previously studied, and was found to be able to form a homomeric receptor when expressed in Xenopus laevis oocytes. In this study, we found that the neonicotinoid insecticide imidacloprid is unable to activate the cockroach Pameα7 receptor, although thiacloprid induces low inward currents, suggesting that it is a partial agonist. In addition, the co-application or 5 min pretreatment with 10 µM imidacloprid increased nicotine current amplitudes, while the co-application or 5 min pretreatment with 10 µM thiacloprid decreased nicotine-evoked current amplitudes by 54% and 28%, respectively. This suggesting that these two representatives of neonicotinoid insecticides bind differently to the cockroach Pameα7 receptor. Interestingly, the docking models demonstrate that the orientation and interactions of the two insecticides in the cockroach Pameα7 nAChR binding pocket are very similar. Electrophysiological results have provided evidence to suggest that imidacloprid and thiacloprid could act as modulators of the cockroach Pameα7 receptors.
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Affiliation(s)
- Alison Cartereau
- Université d’Orléans, LBLGC USC INRAE 1328, 45067 Orléans, France; (A.C.); (E.T.)
| | - Emiliane Taillebois
- Université d’Orléans, LBLGC USC INRAE 1328, 45067 Orléans, France; (A.C.); (E.T.)
| | | | - Steeve H. Thany
- Université d’Orléans, LBLGC USC INRAE 1328, 45067 Orléans, France; (A.C.); (E.T.)
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7
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Jones AK, Goven D, Froger JA, Bantz A, Raymond V. The cys-loop ligand-gated ion channel gene superfamilies of the cockroaches Blattella germanica and Periplaneta americana. PEST MANAGEMENT SCIENCE 2021; 77:3787-3799. [PMID: 33347700 DOI: 10.1002/ps.6245] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/27/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Cockroaches are serious urban pests that can transfer disease-causing microorganisms as well as trigger allergic reactions and asthma. They are commonly managed by pesticides that act on cys-loop ligand-gated ion channels (cysLGIC). To provide further information that will enhance our understanding of how insecticides act on their molecular targets in cockroaches, we used genome and reverse transcriptase polymerase chain reaction (RT-PCR) data to characterize the cysLGIC gene superfamilies from Blattella germanica and Periplaneta americana. RESULTS The B. germanica and P. americana cysLGIC superfamilies consist of 30 and 32 subunit-encoding genes, respectively, which are the largest insect cysLGIC superfamilies characterized to date. As with other insects, the cockroaches possess ion channels predicted to be gated by acetylcholine, γ-aminobutyric acid, glutamate and histamine, as well as orthologues of the drosophila pH-sensitive chloride channel (pHCl), CG8916 and CG12344. The large cysLGIC superfamilies of cockroaches are a result of an expanded number of divergent nicotinic acetylcholine receptor subunits, with B. germanica and P. americana, respectively, possessing eight and ten subunit genes. Diversity of the cockroach cysLGICs is also broadened by alternative splicing and RNA A-to-I editing. Unusually, both cockroach species possess a second glutamate-gated chloride channel as well as another CG8916 subunit. CONCLUSION These findings on B. germanica and P. americana enhance our understanding of the evolution of the insect cysLGIC superfamily and provide a useful basis for the study of their function, the detection and management of insecticide resistance, and for the development of improved pesticides with greater specificity towards these major pests. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Andrew K Jones
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Delphine Goven
- Laboratoire « Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs » (SiFCIR), UPRES-EA2647 USC INRAE 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, Angers, France
| | - Josy-Anne Froger
- Laboratoire « Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs » (SiFCIR), UPRES-EA2647 USC INRAE 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, Angers, France
| | - Alexandre Bantz
- Laboratoire « Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs » (SiFCIR), UPRES-EA2647 USC INRAE 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, Angers, France
| | - Valerie Raymond
- Laboratoire « Signalisation Fonctionnelle des Canaux Ioniques et Récepteurs » (SiFCIR), UPRES-EA2647 USC INRAE 1330, SFR 4207 QUASAV, UFR Sciences, Université d'Angers, Angers, France
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8
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Hashim O, Charvet CL, Toubaté B, Ahmed AAE, Lamassiaude N, Neveu C, Dimier-Poisson I, Debierre-Grockiego F, Dupuy C. Molecular and Functional Characterization of GABA Receptor Subunits GRD and LCCH3 from Human Louse Pediculus Humanus Humanus. Mol Pharmacol 2021; 102:116-127. [PMID: 35858760 PMCID: PMC11037462 DOI: 10.1124/molpharm.122.000499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 04/21/2022] [Accepted: 05/12/2022] [Indexed: 11/22/2022] Open
Abstract
Human louse Pediculus humanus is a cosmopolitan obligatory blood-feeding ectoparasite causing pediculosis and transmitting many bacterial pathogens. Control of infestation is difficult due to the developed resistance to insecticides that mainly target GABA (γ-aminobutyric acid) receptors. Previous work showed that Pediculus humanus humanus (Phh) GABA receptor subunit resistance to dieldrin (RDL) is the target of lotilaner, a synthetic molecule of the isoxazoline chemical class. To enhance our understanding of how insecticides act on GABA receptors, two other GABA receptor subunits were cloned and characterized: three variants of Phh-grd (glycine-like receptor of Drosophila) and one variant of Phh-lcch3 (ligand-gated chloride channel homolog 3). Relative mRNA expression levels of Phh-rdl, Phh-grd, and Phh-lcch3 revealed that they were expressed throughout the developmental stages (eggs, larvae, adults) and in the different parts of adult lice (head, thorax, and abdomen). When expressed individually in the Xenopus oocyte heterologous expression system, Phh-GRD1, Phh-GRD2, Phh-GRD3, and Phh-LCCH3 were unable to reconstitute functional channels, whereas the subunit combinations Phh-GRD1/Phh-LCCH3, Phh-GRD1/Phh-RDL, and Phh-LCCH3/Phh-RDL responded to GABA in a concentration-dependent manner. The three heteromeric receptors were similarly sensitive to the antagonistic effect of picrotoxin and fipronil, whereas Phh-GRD1/Phh-RDL and Phh-LCCH3/Phh-RDL were respectively about 2.5-fold and 5-fold more sensitive to ivermectin than Phh-GRD1/Phh-LCCH3. Moreover, the heteropentameric receptor constituted by Phh-GRD1/Phh-LCCH3 was found to be permeable and highly sensitive to the extracellular sodium concentration. These findings provided valuable additions to our knowledge of the complex nature of GABA receptors in human louse that could help in understanding the resistance pattern to commonly used pediculicides. SIGNIFICANCE STATEMENT: Human louse is an ectoparasite that causes pediculosis and transmits several bacterial pathogens. Emerging strains developed resistance to the commonly used insecticides, especially those targeting GABA receptors. To understand the molecular mechanisms underlying this resistance, two subunits of GABA receptors were cloned and described: Phh-grd and Phh-lcch3. The heteromeric receptor reconstituted with the two subunits was functional in Xenopus oocytes and sensitive to commercially available insecticides. Moreover, both subunits were transcribed throughout the parasite lifecycle.
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Affiliation(s)
- Omar Hashim
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Claude L Charvet
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Berthine Toubaté
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Aimun A E Ahmed
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Nicolas Lamassiaude
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Cédric Neveu
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Isabelle Dimier-Poisson
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Françoise Debierre-Grockiego
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
| | - Catherine Dupuy
- INRAE, Université de Tours, ISP, BioMAP, 37200, Tours, France (O.H., B.T., I.D.-P., F.D.-G., C.D.); Department of Pharmacology, Faculty of Pharmacy, University of Gezira, Wad Madani, Sudan (O.H.); INRAE, Université de Tours, ISP, MPN, 37380, Nouzilly, France (C.L.C., N.L., C.N.); Department of Pharmacology, Albaha University, Alaqiq, Saudi Arabia (A.A.E.A.); and Department of Pharmacology and Toxicology, Omdurman Islamic University, Omdurman, Sudan (A.A.E.A.)
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9
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Nakao T, Banba S. Important amino acids for function of the insect Rdl GABA receptor. PEST MANAGEMENT SCIENCE 2021; 77:3753-3762. [PMID: 33002317 DOI: 10.1002/ps.6121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Insect Rdl GABA receptor is an important insecticide target. To design a novel insecticide, studies on the structures of homologous pentameric ligand-gated ion channels provide information about important amino acids that are necessary for the function of insect Rdl GABA receptors. RESULTS L9'A, T12'A, T13'A, T13'S, M15'S, and M15'N mutations in the Drosophila Rdl GABA receptor subunit caused the protein to spontaneously adopt the open state conformation. In contrast, the S16'A, S16'T, S17'A, and S17'H mutant homomers showed the same levels of agonist and antagonist sensitivity as the wild-type receptor. The G336M mutation in the Drosophila Rdl GABA receptor abolished the agonist activities of ivermectin and milbemectin, but the F339M mutation did not. Additionally, the F339M mutation caused spontaneous opening of the receptor. In the Drosophila Rdl model, the hydrophobic girdle plays an important role in stabilization of the closed state. Mutations which decrease hydrophobic interactions resulted in spontaneous opening, supporting the importance of the hydrophobic girdle for keeping the channel closed. Through a mutational study of transmembrane 3 (TM3) cytoplasmic domain and Rdl GABA receptor modeling, hydrophobic interactions between TM3 and TM4 and intersubunit interaction were demonstrated to be important for channel gating. Alternatively, the intrasubunit interaction between TM2 and TM3 domains were less important for channel gating in case of Drosophila Rdl GABA receptor. CONCLUSION This study demonstrates important amino acids critical to the function of the Drosophila Rdl GABA receptor based on the mutational studies and Drosophila Rdl GABA receptor modeling approach. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Toshifumi Nakao
- Organic Chemistry G, Agrochemicals Research Center, Mitsui Chemicals Agro, Inc., Chiba, Japan
| | - Shinichi Banba
- Organic Chemistry G, Agrochemicals Research Center, Mitsui Chemicals Agro, Inc., Chiba, Japan
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10
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Jiang J, Huang LX, Chen F, Sheng CW, Huang QT, Han ZJ, Zhao CQ. Novel alternative splicing of GABA receptor RDL exon 9 from Laodelphax striatellus modulates agonist potency. INSECT SCIENCE 2021; 28:757-768. [PMID: 32293803 DOI: 10.1111/1744-7917.12789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
The resistance to dieldrin gene (RDL) encodes the primary subunit of the insect ionotropic γ-aminobutyric acid (GABA) receptor (GABAR), which is the target of phenylpyrazole and isoxazoline insecticides. The splice variants in exons 3 and 6 of RDL, which have been widely explored in many insects, modulate the agonist potency of the homomeric RDL GABAR and potentially play an important role in the development of insects. In the present study, four splice variants of exon 9 were identified in RDL of the small brown planthopper, Laodelphax striatellus (LsRDL), resulting in LsRDL-9a, LsRDL-9a', LsRDL-9b, and LsRDL-9c. LsRDL-9a has one more amino acid (E, glutamic acid) compared with LsRDL-9a', and LsRDL-9b lacked two amino acids and had seven different amino acids compared with LsRDL-9c. Two-electrode voltage-clamp recording on LsRDLs expressed in Xenopus oocytes showed that alternative splicing of exon 9 has significant impact on LsRDL sensitivity to the agonists GABA and β-alanine, whereas no significant difference was observed in the potencies of the non-competitive antagonists (NCAs) ethiprole and fluralaner on the splice variants. Our results suggest that alternative splicing of RDL exon 9 broadens functional capabilities of the GABAR in L. striatellus by influencing the action of GABA.
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Affiliation(s)
- Jie Jiang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Li-Xin Huang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Feng Chen
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Cheng-Wang Sheng
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Qiu-Tang Huang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Zhao-Jun Han
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Chun-Qing Zhao
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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The molecular targets of ivermectin and lotilaner in the human louse Pediculus humanus humanus: New prospects for the treatment of pediculosis. PLoS Pathog 2021; 17:e1008863. [PMID: 33600484 PMCID: PMC7891696 DOI: 10.1371/journal.ppat.1008863] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/04/2021] [Indexed: 11/19/2022] Open
Abstract
Control of infestation by cosmopolitan lice (Pediculus humanus) is increasingly difficult due to the transmission of parasites resistant to pediculicides. However, since the targets for pediculicides have no been identified in human lice so far, their mechanisms of action remain largely unknown. The macrocyclic lactone ivermectin is active against a broad range of insects including human lice. Isoxazolines are a new chemical class exhibiting a strong insecticidal potential. They preferentially act on the γ-aminobutyric acid (GABA) receptor made of the resistant to dieldrin (RDL) subunit and, to a lesser extent on glutamate-gated chloride channels (GluCls) in some species. Here, we addressed the pediculicidal potential of isoxazolines and deciphered the molecular targets of ivermectin and the ectoparasiticide lotilaner in the human body louse species Pediculus humanus humanus. Using toxicity bioassays, we showed that fipronil, ivermectin and lotilaner are efficient pediculicides on adult lice. The RDL (Phh-RDL) and GluCl (Phh-GluCl) subunits were cloned and characterized by two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes. Phh-RDL and Phh-GluCl formed functional homomeric receptors respectively gated by GABA and L-glutamate with EC50 values of 16.0 μM and 9.3 μM. Importantly, ivermectin displayed a super agonist action on Phh-GluCl, whereas Phh-RDL receptors were weakly affected. Reversally, lotilaner strongly inhibited the GABA-evoked currents in Phh-RDL with an IC50 value of 40.7 nM, whereas it had no effect on Phh-GluCl. We report here for the first time the insecticidal activity of isoxazolines on human ectoparasites and reveal the mode of action of ivermectin and lotilaner on GluCl and RDL channels from human lice. These results emphasize an expected extension of the use of the isoxazoline drug class as new pediculicidal agents to tackle resistant-louse infestations in humans. Human cosmopolitan lice are responsible for pediculosis, which represent a significant public health concern. Resistant lice against insecticides and lack of safety of the treatments for human and environment is a growing issue worldwide. Here we investigated the efficacy on lice of the classical macrocyclic lactone drug, ivermectin, and of the isoxazoline drug, lotilaner. This study was done to decipher their mode of action at the molecular and functional levels in order to propose new strategies to control lice infestation. Our bioassay results indicate that ivermectin and lotilaner were potent at killing human adult lice, with lotilaner showing a higher efficacy than ivermectin. Furthermore, we identified and pharmacologically characterized the first glutamate- and GABA-gated chloride channels ever described in human lice yet. Mechanistically, our molecular biology and electrophysiology findings demonstrate that ivermectin acted preferentially at glutamate channels, while lotilaner specifically targeted GABA channels. These results provide new insights in the understanding of the insecticide mode of action and highlight the potential of isoxazolines as a new alternative for the treatment of human lice.
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12
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Henry C, Cens T, Charnet P, Cohen-Solal C, Collet C, van-Dijk J, Guiramand J, de Jésus-Ferreira MC, Menard C, Mokrane N, Roussel J, Thibault JB, Vignes M, Rousset M. Heterogeneous expression of GABA receptor-like subunits LCCH3 and GRD reveals functional diversity of GABA receptors in the honeybee Apis mellifera. Br J Pharmacol 2020; 177:3924-3940. [PMID: 32436264 DOI: 10.1111/bph.15135] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 04/24/2020] [Accepted: 05/09/2020] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE Despite a growing awareness, annual losses of honeybee colonies worldwide continue to reach threatening levels for food safety and global biodiversity. Among the biotic and abiotic stresses probably responsible for these losses, pesticides, including those targeting ionotropic GABA receptors, are one of the major drivers. Most insect genomes include the ionotropic GABA receptor subunit gene, Rdl, and two GABA-like receptor subunit genes, Lcch3 and Grd. Most studies have focused on Rdl which forms homomeric GABA-gated chloride channels, and a complete analysis of all possible molecular combinations of GABA receptors is still lacking. EXPERIMENTAL APPROACH We cloned the Rdl, Grd, and Lcch3 genes of Apis mellifera and systematically characterized the resulting GABA receptors expressed in Xenopus oocytes, using electrophysiological assays, fluorescence microscopy and co-immunoprecipitation techniques. KEY RESULTS The cloned subunits interacted with each other, forming GABA-gated heteromeric channels with particular properties. Strikingly, these heteromers were always more sensitive than AmRDL homomer to all the pharmacological agents tested. In particular, when expressed together, Grd and Lcch3 form a non-selective cationic channel that opens at low concentrations of GABA and with sensitivity to insecticides similar to that of homomeric Rdl channels. CONCLUSION AND IMPLICATIONS For off-target species like the honeybee, chronic sublethal exposure to insecticides constitutes a major threat. At these concentration ranges, homomeric RDL receptors may not be the most pertinent target to study and other ionotropic GABA receptor subtypes should be considered in order to understand more fully the molecular mechanisms of sublethal toxicity to insecticides.
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Affiliation(s)
| | - Thierry Cens
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Pierre Charnet
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | | | - Claude Collet
- UR 406 Abeilles et Environnement, INRAE, Avignon Cedex 9, France
| | | | | | | | - Claudine Menard
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Nawfel Mokrane
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Julien Roussel
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | | | - Michel Vignes
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Matthieu Rousset
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
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13
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Cartereau A, Taillebois E, Selvam B, Martin C, Graton J, Le Questel JY, Thany SH. Cloning and Expression of Cockroach α7 Nicotinic Acetylcholine Receptor Subunit. Front Physiol 2020; 11:418. [PMID: 32457646 PMCID: PMC7221154 DOI: 10.3389/fphys.2020.00418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Understanding insect nicotinic acetylcholine receptor (nAChR) subtypes is of major interest because they are the main target of several insecticides. In this study, we have cloned a cockroach Pameα7 subunit that encodes a 518 amino acid protein with futures typical of nAChR subunit, and sequence homology to α7 subunit. Pameα7 is differently expressed in the cockroach nervous system, in particular in the antennal lobes, optical lobes and the mushroom bodies where specific expression was found in the non-compact Kenyon cells. In addition, we found that cockroach Pameα7 subunits expressed in Xenopus laevis oocytes can assemble to form homomeric receptors. Electrophysiological recordings using the two-electrode voltage clamp method demonstrated that nicotine induced an I max current of -92 ± 27 nA at 1 mM. Despite that currents are low with the endogenous ligand, ACh, this study provides information on the first expression of cockroach α7 homomeric receptor.
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Affiliation(s)
- Alison Cartereau
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
| | | | - Balaji Selvam
- Roger Adams Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Carine Martin
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
| | - Jérôme Graton
- CEISAM-UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, Nantes, France
| | - Jean-Yves Le Questel
- CEISAM-UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, Nantes, France
| | - Steeve H. Thany
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
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14
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Sheng CW, Huang QT, Liu GY, Ren XX, Jiang J, Jia ZQ, Han ZJ, Zhao CQ. Neurotoxicity and mode of action of fluralaner on honeybee Apis mellifera L. PEST MANAGEMENT SCIENCE 2019; 75:2901-2909. [PMID: 31081291 DOI: 10.1002/ps.5483] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Fluralaner, a novel pesticide that targets the γ-aminobutyric acid (GABA) receptor (GABAR) subunit of resistant to dieldrin (RDL), exhibits strong potential to be an insecticide to control agricultural insect pests. However, the risk and action of fluralaner to economic insects, e.g., honeybee Apis mellifera Linnaeus, remains unclear. RESULTS In this study, both oral and contact toxicity of fluralaner to honeybee were found to be 0.13 μg adult-1 . Abamectin, dieldrin, ethiprole, α-endosulfan, fipronil and fluralaner strongly inhibited the GABA-induced current in A. mellifera RDL (AmRDL), expressed in Xenopus laevis oocytes, with median inhibitory concentration (IC50 ) values of 7.99, 868.1, 27.10, 412.0, 11.21 and 13.59 nM, respectively. The binding free energy and electrophysiological response of AmRDL and insecticides were opposite. The correlation values between toxicity (to A. mellifera) and binding free energy/electrophysiological inhibition (to AmRDL) were at a moderate level. CONCLUSION In conclusion, we report for the first time the notable risk of fluralaner to honeybee in vivo and compared the actions of GABAR-targeted insecticides on the AmRDL receptor. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Cheng-Wang Sheng
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qiu-Tang Huang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Gen-Yan Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, 430205, China
| | - Xue-Xiang Ren
- Institute of Plant Protection and Agro-Products Safety, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Jie Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhong-Qiang Jia
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhao-Jun Han
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chun-Qing Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
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15
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Huang QT, Sheng CW, Jiang J, Jia ZQ, Han ZJ, Zhao CQ, Liu GY. Functional integrity of honeybee (Apis mellifera L.) resistant to dieldrin γ-aminobutyric acid receptor channels conjugated with three fluorescent proteins. INSECT MOLECULAR BIOLOGY 2019; 28:313-320. [PMID: 30421825 DOI: 10.1111/imb.12552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To generate an efficient tool used in Xenopus oocyte expression for in situ investigation of channel receptor expression, distribution and function, the C-terminus of the honeybee (Apis mellifera L.) resistant to dieldrin (RDL) subunit was fused with *FP, including monomeric red, enhanced yellow or enhanced green fluorescent protein (referred to as mRFP, EYFP and EGFP, respectively). In the present study, all fused *FP-AmRDLs could be visualized using fluorescence and laser confocal microscopy in cRNA-injected oocytes. Fluorescence was distributed isotropically in the cellular membrane. The potencies of the agonist γ-aminobutyric acid (GABA), but not β-alanine, and the test antagonists (fipronil, flufiprole, dieldrin, α-endosulfan, bifenazate and avermectin B1a) in the *FP-AmRDL receptor did not significantly differ from that of the untagged receptor with two-electrode voltage clamp detection. The half maximal effective concentrations (EC50 s) of GABA in AmRDL, EGFP-AmRDL, EYFP-AmRDL and mRFP-AmRDL receptors were 11.98, 12.61, 18.92 and 22.11 μM, respectively, and those of β-alanine were 651.6, 629.6, 1643.0 and 2146.0 μM, respectively. Inhibition percentages of test antagonists against *FP-AmRDL and AmRDL were not significantly different from each other. Overall, the consistency in functional properties between *FP-AmRDL and AmRDL receptors makes pGH19-*FP a promising tool for further in situ investigation of GABA receptors.
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Affiliation(s)
- Q-T Huang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - C-W Sheng
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - J Jiang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Z-Q Jia
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Z-J Han
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - C-Q Zhao
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - G-Y Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, China
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16
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Meng X, Yang X, Zhang N, Jiang H, Ge H, Chen M, Qian K, Wang J. Knockdown of the GABA receptor RDL genes decreases abamectin susceptibility in the rice stem borer, Chilo suppressalis. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 153:171-175. [PMID: 30744892 DOI: 10.1016/j.pestbp.2018.11.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/21/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
The γ-aminobutyric acid (GABA) receptor is a primary neurotransmitter receptor in both vertebrate and invertebrate nervous systems. Multiple RDL subunits have been found in insects including the rice stem borer, Chilo suppressalis, however, comparative characterization of duplicated RDL genes in insects is still limited. In this study, comparison of the genomic sequences and the cDNA sequences revealed that both CsRDL1 and CsRDL2 consisted of 10 exons and 9 introns, and their exon-intron boundaries occur in the same position with respect to the coding sequences. Expression profiling showed that both CsRDL1 and CsRDL2 were predominantly expressed in nervous system, and had low expression levels in the gut and integument. The transcript level of CsRDL2 dramatically increased from the prepupae to late pupae and were much higher than that of CsRDL1 in adult stages. Notably, dietary ingestion of dsRDL1 and dsRDL2 significantly decreased the larval susceptibility to abamectin. These results suggest that CsRDL1 and CsRDL2 might play both physiological roles in development and toxicological roles in action of abamectin in C. suppressalis.
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Affiliation(s)
- Xiangkun Meng
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Xuemei Yang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Nan Zhang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Heng Jiang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Huichen Ge
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Minxuan Chen
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Kun Qian
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Jianjun Wang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
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Ménard C, Folacci M, Brunello L, Charreton M, Collet C, Mary R, Rousset M, Thibaud JB, Vignes M, Charnet P, Cens T. Multiple combinations of RDL subunits diversify the repertoire of GABA receptors in the honey bee parasite Varroa destructor. J Biol Chem 2018; 293:19012-19024. [PMID: 30333227 DOI: 10.1074/jbc.ra118.005365] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/16/2018] [Indexed: 12/22/2022] Open
Abstract
In insects, γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter, and GABA-gated ion channels are the target of different classes of insecticides, including fipronil. We report here the cloning of six subunits (four RDL, one LCCH3, and one GRD) that constitute the repertoire of the GABA-gated ion channel family of the Varroa mite (Varroa destructor), a honey bee ectoparasite. We also isolated a truncated GRD subunit with a premature stop codon. We found that when expressed in Xenopus laevis oocytes, three of the four RDL subunits (VdesRDL1, VdesRDL2, and VdesRDL3) formed functional, homomultimeric anionic receptors, whereas GRD and LCCH3 produced heteromultimeric cationic receptors. These receptors displayed specific sensitivities toward GABA and fipronil, and VdesRDL1 was the most resistant to the insecticide. We identified specific residues in the VdesRDL1 pore-lining region that explain its high resistance to fipronil. VdesRDL4 did not form a functional receptor when expressed alone, but it assembled with VdesRDL1 to form a heteromultimeric receptor with properties distinct from those of the VdesRDL1 homomultimeric receptor. Moreover, VdesRDL1 physically interacted with VdesRDL3, generating a heteromultimeric receptor combining properties of both subunits. On the other hand, we did not detect any functional interaction between VdesLCCH3 and the VdesRDL subunits, an observation that differed from what was previously reported for Drosophila melanogaster In conclusion, this study provides insights relevant to improve our understanding of the precise role of GABAergic signaling in insects and new tools for the development of Varroa mite-specific insecticidal agents that do not harm honey bees.
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Affiliation(s)
- Claudine Ménard
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Mathilde Folacci
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Lorène Brunello
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Mercedes Charreton
- the INRA UR 406 Abeilles et Environnement, 84914 Avignon cedex 9, France
| | - Claude Collet
- the INRA UR 406 Abeilles et Environnement, 84914 Avignon cedex 9, France
| | - Rosanna Mary
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Matthieu Rousset
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Jean-Baptiste Thibaud
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Michel Vignes
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Pierre Charnet
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
| | - Thierry Cens
- From the Institut des Biomolécules Max Mousseron, UMR5247, CNRS, Université de Montpellier, 34095 Montpellier cedex 5, France and
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Cloning and Functional Characterisation of the Duplicated RDL Subunits from the Pea Aphid, Acyrthosiphon pisum. Int J Mol Sci 2018; 19:ijms19082235. [PMID: 30065178 PMCID: PMC6121307 DOI: 10.3390/ijms19082235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 11/17/2022] Open
Abstract
The insect GABA receptor, RDL (resistance to dieldrin), is a cys-loop ligand-gated ion channel (cysLGIC) that plays a central role in neuronal signaling, and is the target of several classes of insecticides. Many insects studied to date possess one Rdl gene; however, there is evidence of two Rdls in aphids. To characterise further this insecticide target from pests that cause millions of dollars' worth of crop damage each year, we identified the complete cysLGIC gene superfamily of the pea aphid, Acyrthosiphon pisum, using BLAST analysis. This confirmed the presence of two Rdl-like genes (RDL1 and RDL2) that likely arose from a recent gene duplication. When expressed individually in Xenopus laevis oocytes, both subunits formed functional ion channels gated by GABA. Alternative splicing of RDL1 influenced the potency of GABA, and the potency of fipronil was different on the RDL1bd splice variant and RDL2. Imidacloprid and clothianidin showed no antagonistic activity on RDL1, whilst 100 μM thiacloprid reduced the GABA responses of RDL1 and RDL2 to 55% and 62%, respectively. It was concluded that gene duplication of Rdl may have conferred increased tolerance to natural insecticides, and played a role in the evolution of insect cysLGICs.
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Taylor-Wells J, Senan A, Bermudez I, Jones AK. Species specific RNA A-to-I editing of mosquito RDL modulates GABA potency and influences agonistic, potentiating and antagonistic actions of ivermectin. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 93:1-11. [PMID: 29223796 DOI: 10.1016/j.ibmb.2017.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/30/2017] [Accepted: 12/03/2017] [Indexed: 06/07/2023]
Abstract
The insect GABA receptor, RDL, is the target of several classes of pesticides. The peptide sequences of RDL are generally highly conserved between diverse insects. However, RNA A-to-I editing can effectively alter amino acid residues of RDL in a species specific manner, which can affect the potency of GABA and possibly insecticides. We report here that RNA A-to-I editing alters the gene products of Rdl in three mosquito disease vectors, recoding five amino acid residues in RDL of Aedes aegypti and six residues in RDLs of Anopheles gambiae and Culex pipiens, which is the highest extent of editing in RDL observed to date. Analysis of An. gambiae Rdl cDNA sequences identified 24 editing isoforms demonstrating a considerable increase in gene product diversity. RNA editing influenced the potency of the neurotransmitter, GABA, on An. gambiae RDL editing isoforms expressed in Xenopus laevis oocytes, as demonstrated by EC50s ranging from 5 ± 1 to 246 ± 41 μM. Fipronil showed similar potency on different editing isoforms, with IC50s ranging from 0.18 ± 0.08 to 0.43 ± 0.09 μM. In contrast, editing of An. gambiae RDL affected the activating, potentiating and inhibiting actions of ivermectin. For example, ivermectin potentiated currents induced by GABA at the EC20 concentration in the unedited isoform but not in the fully edited variant. Editing of a residue in the first transmembrane domain or the cys-loop influenced this potentiation, highlighting residues involved in the allosteric mechanisms of cys-loop ligand-gated ion channels. Understanding the interactions of ivermectin with molecular targets may have relevance to mosquito control in areas where people are administered with ivermectin to treat parasitic diseases.
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Affiliation(s)
- Jennina Taylor-Wells
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, OX30BP, UK.
| | - Anish Senan
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, OX30BP, UK.
| | - Isabel Bermudez
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, OX30BP, UK.
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, OX30BP, UK.
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Jones AK. How Complex Can Resistance to Dieldrin, the Insect γ-Aminobutyric Acid Receptor, Get? INTERNATIONAL JOURNAL OF INSECT SCIENCE 2018; 10:1179543318804782. [PMID: 30559597 PMCID: PMC6291865 DOI: 10.1177/1179543318804782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/09/2018] [Indexed: 05/20/2023]
Abstract
Recently, Taylor-Wells et al published evidence that the γ-aminobutyric acid (GABA) receptor, resistance to dieldrin (RDL), from mosquitoes undergoes RNA A-to-I editing to generate an extraordinarily large range of isoforms. This editing was found to affect GABA receptor pharmacology, as it influenced the potency of GABA and ivermectin. This highlights RNA editing as a species-specific mechanism to fine-tune receptor function as well as possibly increase tolerance of mosquitoes to certain insecticides. This commentary also considers novel findings from analysis of Rdl transcripts from individual mosquitoes taken from different geographical areas.
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Affiliation(s)
- Andrew K Jones
- Andrew K Jones, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK.
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21
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Taylor-Wells J, Jones AK. Variations in the Insect GABA Receptor, RDL, and Their Impact on Receptor Pharmacology. ACS SYMPOSIUM SERIES 2017. [DOI: 10.1021/bk-2017-1265.ch001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jennina Taylor-Wells
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford OX3 8NZ, United Kingdom
| | - Andrew K. Jones
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford OX3 8NZ, United Kingdom
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