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Hadiatullah H, Zhang Y, Samurkas A, Xie Y, Sundarraj R, Zuilhof H, Qiao J, Yuchi Z. Recent progress in the structural study of ion channels as insecticide targets. INSECT SCIENCE 2022; 29:1522-1551. [PMID: 35575601 DOI: 10.1111/1744-7917.13032] [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: 10/13/2021] [Revised: 02/07/2022] [Accepted: 02/21/2022] [Indexed: 06/15/2023]
Abstract
Ion channels, many expressed in insect neural and muscular systems, have drawn huge attention as primary targets of insecticides. With the recent technical breakthroughs in structural biology, especially in cryo-electron microscopy (cryo-EM), many new high-resolution structures of ion channel targets, apo or in complex with insecticides, have been solved, shedding light on the molecular mechanism of action of the insecticides and resistance mutations. These structures also provide accurate templates for structure-based insecticide screening and rational design. This review summarizes the recent progress in the structural studies of 5 ion channel families: the ryanodine receptor (RyR), the nicotinic acetylcholine receptor (nAChR), the voltage-gated sodium channel (VGSC), the transient receptor potential (TRP) channel, and the ligand-gated chloride channel (LGCC). We address the selectivity of the channel-targeting insecticides by examining the conservation of key coordinating residues revealed by the structures. The possible resistance mechanisms are proposed based on the locations of the identified resistance mutations on the 3D structures of the target channels and their impacts on the binding of insecticides. Finally, we discuss how to develop "green" insecticides with a novel mode of action based on these high-resolution structures to overcome the resistance.
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Affiliation(s)
- Hadiatullah Hadiatullah
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Yongliang Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Arthur Samurkas
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Yunxuan Xie
- Department of Environmental Science, Tianjin University, Tianjin, China
| | - Rajamanikandan Sundarraj
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Han Zuilhof
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Jianjun Qiao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy, Tianjin; Tianjin's Clinical Research Center for Cancer, Tianjin, China
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Abstract
Human and animal welfare primarily depends on the availability of food and surrounding environment. Over a century and half, the quest to identify agents that can enhance food production and protection from vector borne diseases resulted in the identification and use of a variety of pesticides, of which the pyrethroid based ones emerged as the best choice. Pesticides while improved the quality of life, on the other hand caused enormous health risks. Because of their percolation into drinking water and food chain and usage in domestic settings, humans unintentionally get exposed to the pesticides on a daily basis. The health hazards of almost all known pesticides at a variety of doses and exposure times are reported. This review provides a comprehensive summation on the historical, epidemiological, chemical and biological (physiological, biochemical and molecular) aspects of pyrethroid based insecticides. An overview of the available knowledge suggests that the synthetic pyrethroids vary in their chemical and toxic nature and pose health hazards that range from simple nausea to cancers. Despite large number of reports, studies that focused on identifying the health hazards using doses that are equivalent or relevant to human exposure are lacking. It is high time such studies are conducted to provide concrete evidence on the hazards of consuming pesticide contaminated food. Policy decisions to decrease the residual levels of pesticides in agricultural products and also to encourage organic farming is suggested.
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Affiliation(s)
| | - Suresh Yenugu
- Department of Animal Biology, University of Hyderabad, Hyderabad, India
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Dong K, Du Y, Rinkevich F, Nomura Y, Xu P, Wang L, Silver K, Zhorov BS. Molecular biology of insect sodium channels and pyrethroid resistance. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 50:1-17. [PMID: 24704279 PMCID: PMC4484874 DOI: 10.1016/j.ibmb.2014.03.012] [Citation(s) in RCA: 286] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/24/2014] [Accepted: 03/24/2014] [Indexed: 05/06/2023]
Abstract
Voltage-gated sodium channels are essential for the initiation and propagation of the action potential in neurons and other excitable cells. Because of their critical roles in electrical signaling, sodium channels are targets of a variety of naturally occurring and synthetic neurotoxins, including several classes of insecticides. This review is intended to provide an update on the molecular biology of insect sodium channels and the molecular mechanism of pyrethroid resistance. Although mammalian and insect sodium channels share fundamental topological and functional properties, most insect species carry only one sodium channel gene, compared to multiple sodium channel genes found in each mammalian species. Recent studies showed that two posttranscriptional mechanisms, alternative splicing and RNA editing, are involved in generating functional diversity of sodium channels in insects. More than 50 sodium channel mutations have been identified to be responsible for or associated with knockdown resistance (kdr) to pyrethroids in various arthropod pests and disease vectors. Elucidation of molecular mechanism of kdr led to the identification of dual receptor sites of pyrethroids on insect sodium channels. Many of the kdr mutations appear to be located within or close to the two receptor sites. The accumulating knowledge of insect sodium channels and their interactions with insecticides provides a foundation for understanding the neurophysiology of sodium channels in vivo and the development of new and safer insecticides for effective control of arthropod pests and human disease vectors.
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Affiliation(s)
- Ke Dong
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA.
| | - Yuzhe Du
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA
| | - Frank Rinkevich
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA
| | - Yoshiko Nomura
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA
| | - Peng Xu
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA
| | - Lingxin Wang
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, MI, USA
| | - Kristopher Silver
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, USA
| | - Boris S Zhorov
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada; Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
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Silver KS, Du Y, Nomura Y, Oliveira EE, Salgado VL, Zhorov BS, Dong K. Voltage-Gated Sodium Channels as Insecticide Targets. ADVANCES IN INSECT PHYSIOLOGY 2014; 46:389-433. [PMID: 29928068 PMCID: PMC6005695 DOI: 10.1016/b978-0-12-417010-0.00005-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Voltage-gated sodium channels are critical for the generation and propagation of action potentials. They are the primary target of several classes of insecticides, including DDT, pyrethroids and sodium channel blocker insecticides (SCBIs). DDT and pyrethroids preferably bind to open sodium channels and stabilize the open state, causing prolonged currents. In contrast, SCBIs block sodium channels by binding to the inactivated state. Many sodium channel mutations are associated with knockdown resistance (kdr) to DDT and pyrethroids in diverse arthropod pests. Functional characterization of kdr mutations together with computational modelling predicts dual pyrethroid receptor sites on sodium channels. In contrast, the molecular determinants of the SCBI receptor site remain largely unknown. In this review, we summarize current knowledge about the molecular mechanisms of action of pyrethroids and SCBIs, and highlight the differences in the molecular interaction of these insecticides with insect versus mammalian sodium channels.
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Affiliation(s)
- Kristopher S Silver
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas, USA
| | - Yuzhe Du
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, Michigan, USA
| | - Yoshiko Nomura
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, Michigan, USA
| | - Eugenio E Oliveira
- Departamento de Entomologia, Universidade Federal de Vic¸osa, Vic¸osa, Minas Gerais, Brasil
| | - Vincent L Salgado
- BASF Agricultural Products, BASF Corporation, Research Triangle Park, North Carolina, USA
| | - Boris S Zhorov
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Ke Dong
- Department of Entomology, Neuroscience and Genetics Programs, Michigan State University, East Lansing, Michigan, USA
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Oliveira EE, Du Y, Nomura Y, Dong K. A residue in the transmembrane segment 6 of domain I in insect and mammalian sodium channels regulate differential sensitivities to pyrethroid insecticides. Neurotoxicology 2013; 38:42-50. [PMID: 23764339 PMCID: PMC3773218 DOI: 10.1016/j.neuro.2013.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/03/2013] [Accepted: 06/03/2013] [Indexed: 02/05/2023]
Abstract
Voltage-gated sodium channels are critical for electrical signaling in the nervous system. Pyrethroid insecticides exert their toxic action by modifying the gating of sodium channels. A valine to methionine mutation in the transmembrane segment 6 of domain I (IS6) of sodium channels from tobacco budworms (Heliothis virescens) has been shown to alter channel gating and reduce insect sodium channel sensitivity to pyrethroids. A valine to leucine substitution was subsequently reported in pyrethroid-resistant bedbug populations. Intriguingly, pyrethroid-resistant mammalian sodium channels possess an isoleucine at the corresponding position. To determine whether different substitutions at this position alter channel gating and confer pyrethroid resistance, we made valine to methionine, isoleucine or leucine substitutions at the corresponding position, V409, in a cockroach sodium channel and examined the gating properties and pyrethroid sensitivity of the three mutants in Xenopus oocytes. All three mutations reduced the channel sensitivity to three pyrethroids (permethrin, cismethrin and deltamethrin). V409M, but not V409I or V409L, caused 6-7mV depolarizing shifts in the voltage dependences of both activation and inactivation. V409M and V409L slowed channel activation kinetics and accelerated open-state deactivation kinetics, but V409I did not. Furthermore, the substitution of isoleucine with valine, but not with methionine nor leucine, at the corresponding position in a rat skeletal muscle sodium channel, rNav1.4, enhanced channel sensitivity to deltamethrin. Collectively, our study highlights an important role of residues at 409 in regulating not only sodium channel gating, but also the differential sensitivities of insect and mammalian sodium channels to pyrethroids.
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Affiliation(s)
| | - Yuzhe Du
- Department of Entomology, Genetics and Neuroscience Programs; Michigan State University; East Lansing, MI 48824, USA
| | - Yoshiko Nomura
- Department of Entomology, Genetics and Neuroscience Programs; Michigan State University; East Lansing, MI 48824, USA
| | - Ke Dong
- Department of Entomology, Genetics and Neuroscience Programs; Michigan State University; East Lansing, MI 48824, USA
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Rinkevich FD, Du Y, Dong K. Diversity and Convergence of Sodium Channel Mutations Involved in Resistance to Pyrethroids. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2013; 106:93-100. [PMID: 24019556 PMCID: PMC3765034 DOI: 10.1016/j.pestbp.2013.02.007] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pyrethroid insecticides target voltage-gated sodium channels, which are critical for electrical signaling in the nervous system. The intensive use of pyrethroids in controlling arthropod pests and disease vectors has led to many instances of pyrethroid resistance around the globe. In the past two decades, studies have identified a large number of sodium channel mutations that are associated with resistance to pyrethroids. The purpose of this review is to summarize both common and unique sodium channel mutations that have been identified in arthropod pests of importance to agriculture or human health. Identification of these mutations provides valuable molecular markers for resistance monitoring in the field and helped the discovery of the elusive pyrethroid receptor site(s) on the sodium channel.
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Affiliation(s)
- Frank D Rinkevich
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824-1115 USA
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Davies TGE, Field LM, Williamson MS. The re-emergence of the bed bug as a nuisance pest: implications of resistance to the pyrethroid insecticides. MEDICAL AND VETERINARY ENTOMOLOGY 2012; 26:241-54. [PMID: 22235873 DOI: 10.1111/j.1365-2915.2011.01006.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A global resurgence of bed bugs (Hemiptera: Cimicidae) has led to renewed scientific interest in these insects. The current bed bug upsurge appears to have started almost synchronously in the late 1990 s in Europe, the U.S.A. and Australia. Several factors have led to this situation, with resistance to applied insecticides making a significant contribution. With a growing number of insecticides (DDT, carbamates, organophosphates etc.) being no longer available as a result of regulatory restrictions, the mainstay chemistry used for bed bug control over the past few decades has been the pyrethroid insecticides. With reports of increasing tolerance to pyrethroids leading to control failures on the rise, containing and eradicating bed bugs is proving to be a difficult task. Consequently, several recent studies have focused on determining the mode of action of pyrethroid resistance in bed bug populations sourced from different locations. Correct identification of the factor(s) responsible for the increasing resistance is critical to the development of effective management strategies, which need to be based, wherever possible, on firm scientific evidence. Here we review the literature on this topic, highlighting the mechanisms thought to be involved and the problems currently faced by pest control professionals in dealing with a developing pandemic.
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Affiliation(s)
- T G E Davies
- Department of Biological Chemistry, Rothamsted Research, Harpenden, UK.
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Tan J, Soderlund DM. Actions of Tefluthrin on Rat Na(v)1.7 Voltage-Gated Sodium Channels Expressed in Xenopus Oocytes. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2011; 101:21-26. [PMID: 21966053 PMCID: PMC3181098 DOI: 10.1016/j.pestbp.2011.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In rats expression of the Na(v)1.7 voltage-gated sodium channel isoform is restricted to the peripheral nervous system and is abundant in the sensory neurons of the dorsal root ganglion. We expressed the rat Na(v)1.7 sodium channel α subunit together with the rat auxiliary β1 and β2 subunits in Xenopus laevis oocytes and assessed the effects of the pyrethroid insecticide tefluthrin on the expressed currents using the two-electrode voltage clamp method. Tefluthrin at 100 µM modified of Na(v)1.7 channels to prolong inactivation of the peak current during a depolarizing pulse, resulting in a marked "late current" at the end of a 40-ms depolarization, and induced a sodium tail current following repolarization. Tefluthrin modification was enhanced up to two-fold by the application of a train of up to 100 5-ms depolarizing prepulses. These effects of tefluthrin on Na(v)1.7 channels were qualitatively similar to its effects on rat Na(v)1.2, Na(v)1.3 and Na(v)1.6 channels assayed previously under identical conditions. However, Na(v)1.7 sodium channels were distinguished by their low sensitivity to modification by tefluthrin, especially compared to Na(v)1.3 and Na(v)1.6 channels. It is likely that Na(v)1.7 channels contribute significantly to the tetrodotoxin-sensitive, pyrethroid-resistant current found in cultured dorsal root ganglion neurons. We aligned the complete amino acid sequences of four pyrethroid-sensitive isoforms (house fly Vssc1; rat Na(v)1.3, Na(v)1.6 and Na(v)1.8) and two pyrethroid-resistant isoforms (rat Na(v)1.2 and Na(v)1.7) and found only a single site, located in transmembrane segment 6 of homology domain I, at which the amino acid sequence was conserved among all four sensitive isoform sequences but differed in the two resistant isoform sequences. This position, corresponding to Val410 of the house fly Vssc1 sequence, also aligns with sites of multiple amino acid substitutions identified in the sodium channel sequences of pyrethroid-resistant insect populations. These results implicate this single amino acid polymorphism in transmembrane segment 6 of sodium channel homology domain I as a determinant of the differential pyrethroid sensitivity of rat sodium channel isoforms.
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Affiliation(s)
- Jianguo Tan
- Insecticide Toxicology Laboratory, Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, New York 14456, USA
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Molecular mechanisms of pyrethroid insecticide neurotoxicity: recent advances. Arch Toxicol 2011; 86:165-81. [PMID: 21710279 DOI: 10.1007/s00204-011-0726-x] [Citation(s) in RCA: 327] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 06/09/2011] [Indexed: 12/19/2022]
Abstract
Synthetic pyrethroid insecticides were introduced into widespread use for the control of insect pests and disease vectors more than three decades ago. In addition to their value in controlling agricultural pests, pyrethroids are at the forefront of efforts to combat malaria and other mosquito-borne diseases and are also common ingredients of household insecticide and companion animal ectoparasite control products. The abundance and variety of pyrethroid uses contribute to the risk of exposure and adverse effects in the general population. The insecticidal actions of pyrethroids depend on their ability to bind to and disrupt voltage-gated sodium channels of insect nerves. Sodium channels are also important targets for the neurotoxic effects of pyrethroids in mammals but other targets, particularly voltage-gated calcium and chloride channels, have been implicated as alternative or secondary sites of action for a subset of pyrethroids. This review summarizes information published during the past decade on the action of pyrethroids on voltage-gated sodium channels as well as on voltage-gated calcium and chloride channels and provides a critical re-evaluation of the role of these three targets in pyrethroid neurotoxicity based on this information.
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Abstract
The ability to clone, express, and electrophysiologically measure currents carried by voltage-gated ion channels has allowed a detailed assessment of the action of pyrethroids on various target proteins.Recently, the heterologous expression of various rat brain voltage-gated sodium channel isoforms in Xenopus laevis oocytes has determined a wide range of sensitivities to the pyrethroids, with some channels virtually insensitive and others highly sensitive. Furthermore, some isoforms show selective sensitivity to certain pyrethroids and this selectivity can be altered in a state-dependent manner. Additionally, some rat brain isoforms are apparently more sensitive to pyrethroids than the corresponding human isoform. These finding may have significant relevance in judging the merit and value of assessing the risk of pyrethroid exposures to humans using toxicological studies done in rat.Other target sites for certain pyrethroids include the voltage-gated calcium and chloride channels. Of particular interest is the increased effect of Type II pyrethroids on certain phosphoforms of the N-type Ca(v)2.2 calcium channel following post-translational modification and its relationship to enhanced neurotransmitter release seen in vivo.Lastly, parallel neurobehavioral and mechanistic studies on three target sites suggest that a fundamental difference exists between the action of Types I and II pyrethroids, both on a functional and molecular level. These differences should be considered in any future risk evaluation of the pyrethroids.
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Yoon KS, Kwon DH, Strycharz JP, Hollingsworth CS, Lee SH, Clark JM. Biochemical and molecular analysis of deltamethrin resistance in the common bed bug (Hemiptera: Cimicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2008; 45:1092-1101. [PMID: 19058634 DOI: 10.1603/0022-2585(2008)45[1092:bamaod]2.0.co;2] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This study establishes deltamethrin resistance in a common bed bug, Cimex lectularius L., population collected from New York City (NY-BB). The NY-BB population was 264-fold more resistant to 1% deltamethrin in contact bioassay compared with an insecticide-susceptible population collected in Florida (FL-BB). General esterase, glutathione S-transferase, and 7-ethoxycoumarin O-deethylase activities of NY-BB were not statistically different from those of FL-BB. cDNA fragments that encoded the open reading frame of voltage-sensitive sodium channel alpha-subunit genes from the FL-BB and NY-BB populations, respectively, were obtained by homology probing polymerase chain reaction (PCR) and sequenced. Sequence alignment of the internal and 5' and 3' rapid amplification of cDNA ends (RACE) fragments generated a 6500-bp cDNA sequence contig, which was composed of a 6084-bp open reading frame (ORF) encoding 2027 amino acid residues and 186-bp 5' and 230-bp 3' untranslated regions (5' and 3' UTRs, respectively). Sequence comparisons of the open reading frames of the alpha-subunit genes identified two point mutations (V419L and L925I) that were presented only in the NY-BB population. L925I, located the intracellular loop between IIS4 and IIS5, has been previously found in a highly pyrethroid-resistant populations of whitefly (Bemisia tabaci). V419L, located in the IS6 transmembrane segment, is a novel mutation. A Val to Met mutation at the corresponding position of the bed bug V419, however, has been identified in the tobacco budworm as a kdr-type mutation. This evidence suggests that the two mutations are likely the major resistance-causing mutations in the deltamethrin-resistant NY-BB through a knockdown-type nerve insensitivity mechanism.
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Affiliation(s)
- Kyong Sup Yoon
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
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12
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Soderlund DM. Pyrethroids, knockdown resistance and sodium channels. PEST MANAGEMENT SCIENCE 2008; 64:610-616. [PMID: 18383430 DOI: 10.1002/ps.1574] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Knockdown resistance to DDT and the pyrethrins was first described in 1951 in the housefly (Musca domestica L.). This trait, which confers reduced neuronal sensitivity to these insecticides, was subsequently shown to confer cross-resistance to all synthetic pyrethroid insecticides that have been examined to date. As a consequence, the worldwide commercial development of pyrethroids as a major insecticide class over the past three decades has required constant awareness that pyrethroid overuse has the potential to reselect this powerful resistance mechanism in populations that previously were resistant to DDT. Demonstration of tight genetic linkage between knockdown resistance and the housefly gene encoding voltage-sensitive sodium channels spurred efforts to identify gene mutations associated with knockdown resistance and understand how these mutations confer a reduction in the sensitivity of the pyrethroid target site. This paper summarizes progress in understanding pyrethroid resistance at the molecular level, with particular emphasis on studies in the housefly.
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Affiliation(s)
- David M Soderlund
- Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA.
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Watkins JA, Meacham CA, Crofton KM, Shafer TJ. Concentration-dependent accumulation of [3H]-deltamethrin in sodium channel Nav1.2/β1 expressing Xenopus laevis oocytes. Toxicol In Vitro 2007; 21:1672-7. [PMID: 17574382 DOI: 10.1016/j.tiv.2007.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 05/08/2007] [Indexed: 10/23/2022]
Abstract
Disruption of neuronal voltage-sensitive sodium channels (VSSCs) by pyrethroid insecticides such as deltamethrin (DLT) has been widely studied using Xenopus laevis oocytes transfected with VSSC. However, the extent of pyrethroid accumulation in VSSC-expressing oocytes is unknown. Therefore, accumulation of [(3)H]-DLT in non-transfected, sham (water)-transfected and VSSC (Na(v)1.2+beta(1))-transfected oocytes after a 1h exposure was measured using liquid scintillation counting. Successful transfection of Na(v)1.2+beta(1) VSSCs in X. laevis oocytes was confirmed by two-electrode voltage-clamp; inward, tetrodotoxin (TTX)-sensitive currents were obtained in 98% of all oocytes examined (n=60 in nine experiments). DLT (1.0 microM) induced tail currents in all VSSC-transfected oocytes; TTX also blocked these DLT-induced tail currents. In 0.1 microM DLT solution, non-transfected oocytes accumulated 0.098+/-0.01 ppm [(3)H]-DLT, sham-transfected oocytes accumulated 0.06+/-0.01 ppm DLT, and VSSC-transfected oocytes accumulated 0.050+/-0.009 ppm DLT. In 1.0 microM DLT solution, non-transfected oocytes accumulated 0.62+/-0.08 ppm DLT, sham-transfected oocytes accumulated 0.60+/-0.09 ppm DLT, and VSSC-transfected oocytes accumulated 0.51+/-0.07 ppm DLT. There was a significant difference in DLT accumulation between VSSC-transfected oocytes and non-transfected controls, where the transfected oocytes consistently had less accumulation.
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Dong K. Insect sodium channels and insecticide resistance. INVERTEBRATE NEUROSCIENCE : IN 2007; 7:17-30. [PMID: 17206406 PMCID: PMC3052376 DOI: 10.1007/s10158-006-0036-9] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 12/12/2006] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels are essential for the generation and propagation of action potentials (i.e., electrical impulses) in excitable cells. Although most of our knowledge about sodium channels is derived from decades of studies of mammalian isoforms, research on insect sodium channels is revealing both common and unique aspects of sodium channel biology. In particular, our understanding of the molecular dynamics and pharmacology of insect sodium channels has advanced greatly in recent years, thanks to successful functional expression of insect sodium channels in Xenopus oocytes and intensive efforts to elucidate the molecular basis of insect resistance to insecticides that target sodium channels. In this review, I discuss recent literature on insect sodium channels with emphases on the prominent role of alternative splicing and RNA editing in the generation of functionally diverse sodium channels in insects and the current understanding of the interactions between insect sodium channels and insecticides.
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Affiliation(s)
- Ke Dong
- Department of Entomology, Genetics Program and Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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O'Reilly A, Khambay B, Williamson M, Field L, WAllace B, Davies T. Modelling insecticide-binding sites in the voltage-gated sodium channel. Biochem J 2006; 396:255-63. [PMID: 16475981 PMCID: PMC1462714 DOI: 10.1042/bj20051925] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A homology model of the housefly voltage-gated sodium channel was developed to predict the location of binding sites for the insecticides fenvalerate, a synthetic pyrethroid, and DDT an early generation organochlorine. The model successfully addresses the state-dependent affinity of pyrethroid insecticides, their mechanism of action and the role of mutations in the channel that are known to confer insecticide resistance. The sodium channel was modelled in an open conformation with the insecticide-binding site located in a hydrophobic cavity delimited by the domain II S4-S5 linker and the IIS5 and IIIS6 helices. The binding cavity is predicted to be accessible to the lipid bilayer and therefore to lipid-soluble insecticides. The binding of insecticides and the consequent formation of binding contacts across different channel elements could stabilize the channel when in an open state, which is consistent with the prolonged sodium tail currents induced by pyrethroids and DDT. In the closed state, the predicted alternative positioning of the domain II S4-S5 linker would result in disruption of pyrethroid-binding contacts, consistent with the observation that pyrethroids have their highest affinity for the open channel. The model also predicts a key role for the IIS5 and IIIS6 helices in insecticide binding. Some of the residues on the helices that form the putative binding contacts are not conserved between arthropod and non-arthropod species, which is consistent with their contribution to insecticide species selectivity. Additional binding contacts on the II S4-S5 linker can explain the higher potency of pyrethroid insecticides compared with DDT.
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Affiliation(s)
- Andrias O. O'Reilly
- *Department of Crystallography, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
| | - Bhupinder P. S. Khambay
- †Biological Chemistry Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
| | - Martin S. Williamson
- †Biological Chemistry Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
| | - Linda M. Field
- †Biological Chemistry Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
| | - B. A. WAllace
- *Department of Crystallography, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
- Correspondence should be addressed to either of these authors (email or )
| | - T. G. Emyr Davies
- †Biological Chemistry Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
- Correspondence should be addressed to either of these authors (email or )
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Du Y, Liu Z, Nomura Y, Khambay B, Dong K. An alanine in segment 3 of domain III (IIIS3) of the cockroach sodium channel contributes to the low pyrethroid sensitivity of an alternative splice variant. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2006; 36:161-8. [PMID: 16431283 PMCID: PMC3057056 DOI: 10.1016/j.ibmb.2005.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 11/23/2005] [Accepted: 11/24/2005] [Indexed: 05/06/2023]
Abstract
In a previous study, we showed that two alternative exons (G1 and G2 encoding IIIS3-S4) were involved in the differential sensitivity of two cockroach sodium channel splice variants, BgNa(v)1-1 and BgNa(v)2-1 (previously called KD1 and KD2), to deltamethrin, a pyrethroid insecticide (Tan, et al., 2002b. Alternative splicing of an insect sodium channel gene generates pharmacologically distinct sodium channels. J. Neurosci. 22, 5300-5309.). Here, we report the identification of an amino acid residue in exon G2 that contributes to the low deltamethrin sensitivity of BgNa(v)2-1. Replacement of A1356 in BgNa(v)2-1 with the corresponding V1356 in BgNa(v)1-1 enhanced the sensitivity of the BgNa(v)2-1 channel to deltamethrin by six-fold. Conversely, substitution of V1356 with A1356 in BgNa(v)1-1 produced a recombinant BgNa(v)1-1 channel that was 5-fold more resistant to deltamethrin. These results demonstrate that A1356 contributes to the low sensitivity of BgNa(v)2-1 to deltamethrin. A1356V substitution also shifted the voltage-dependence of activation by 10 mV in the hyperpolarizing direction. Possible mechanisms by which this amino acid change affects the action of pyrethroids on the sodium channel are discussed.
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Affiliation(s)
- Yuzhe Du
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Zhiqi Liu
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Yoshiko Nomura
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Bhupinder Khambay
- Biological Chemistry Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Ke Dong
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
- Corresponding author. Tel.: +1 517 432 2034; fax: +1 517 353 5598. (K. Dong)
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Shafer TJ, Meyer DA, Crofton KM. Developmental neurotoxicity of pyrethroid insecticides: critical review and future research needs. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:123-36. [PMID: 15687048 PMCID: PMC1277854 DOI: 10.1289/ehp.7254] [Citation(s) in RCA: 326] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 10/14/2004] [Indexed: 05/17/2023]
Abstract
Pyrethroid insecticides have been used for more than 40 years and account for 25% of the worldwide insecticide market. Although their acute neurotoxicity to adults has been well characterized, information regarding the potential developmental neurotoxicity of this class of compounds is limited. There is a large age dependence to the acute toxicity of pyrethroids in which neonatal rats are at least an order of magnitude more sensitive than adults to two pyrethroids. There is no information on age-dependent toxicity for most pyrethroids. In the present review we examine the scientific data related to potential for age-dependent and developmental neurotoxicity of pyrethroids. As a basis for understanding this neurotoxicity, we discuss the heterogeneity and ontogeny of voltage-sensitive sodium channels, a primary neuronal target of pyrethroids. We also summarize 22 studies of the developmental neurotoxicity of pyrethroids and review the strengths and limitations of these studies. These studies examined numerous end points, with changes in motor activity and muscarinic acetylcholine receptor density the most common. Many of the developmental neurotoxicity studies suffer from inadequate study design, problematic statistical analyses, use of formulated products, and/or inadequate controls. These factors confound interpretation of results. To better understand the potential for developmental exposure to pyrethroids to cause neurotoxicity, additional, well-designed and well-executed developmental neurotoxicity studies are needed. These studies should employ state-of-the-science methods to promote a greater understanding of the mode of action of pyrethroids in the developing nervous system.
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Affiliation(s)
- Timothy J Shafer
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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Tomita T, Yaguchi N, Mihara M, Takahashi M, Agui N, Kasai S. Molecular analysis of a para sodium channel gene from pyrethroid-resistant head lice, Pediculus humanus capitis (Anoplura: Pediculidae). JOURNAL OF MEDICAL ENTOMOLOGY 2003; 40:468-474. [PMID: 14680113 DOI: 10.1603/0022-2585-40.4.468] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The problem of pyrethroid-resistance in head lice, Pediculus humanus capitis (De Geer), is growing worldwide, and an insensitive sodium channel is suspected as the major mechanism of this resistance. We sequenced an open reading frame (ORF) encoding for the para-orthologous sodium channel from an insecticide-susceptible strain of the body louse, Pediculus humanus humanus (L.), based on conserved peptide sequences and a known partial gene sequence. Phenothrin-susceptible and -resistant head louse colonies from Japanese were individually analyzed for point mutations of the sodium channel cDNA; susceptible head and body lice differed in double homozygous synonymous substitutions. The resistant head lice shared 23 base substitutions homozygously, in which four resulted in amino acid substitutions: D11E in the N-terminal inner-membrane segment; M850T in the outer-membrane loop between segments four and five of domain II; T952I and L955 F in the trans-membrane segment five of domain II. The latter two substitutions coincided with those of pyrethroid-resistant head lice in the U.S. and U.K. (Lee et al. 2000), within the available published information on the peptide sequences. The potential mechanisms of head louse pyrethroid-resistance are discussed based on the four structural changes of the target molecule.
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Affiliation(s)
- Takashi Tomita
- Department of Medical Entomology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.
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Soderlund DM, Knipple DC. The molecular biology of knockdown resistance to pyrethroid insecticides. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:563-577. [PMID: 12770575 DOI: 10.1016/s0965-1748(03)00023-7] [Citation(s) in RCA: 274] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The term "knockdown resistance" is used to describe cases of resistance to diphenylethane (e.g. DDT) and pyrethroid insecticides in insects and other arthropods that result from reduced sensitivity of the nervous system. Knockdown resistance, first identified and characterized in the house fly (Musca domestica) in the 1950's, remains a threat to the continued usefulness of pyrethroids in the control of many pest species. Research since 1990 has provided a wealth of new information on the molecular basis of knockdown resistance. This paper reviews these recent developments with emphasis on the results of genetic linkage analyses, the identification of gene mutations associated with knockdown resistance, and the functional characterization of resistance-associated mutations. Results of these studies identify voltage-sensitive sodium channel genes orthologous to the para gene of Drosophila melanogaster as the site of multiple knockdown resistance mutations and define the molecular mechanisms by which these mutations cause pyrethroid resistance. These results also provide new insight into the mechanisms by which pyrethroids modify the function of voltage-sensitive sodium channels.
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Affiliation(s)
- D M Soderlund
- Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA.
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Alternative splicing of an insect sodium channel gene generates pharmacologically distinct sodium channels. J Neurosci 2002. [PMID: 12097481 DOI: 10.1523/jneurosci.22-13-05300.2002] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alternative splicing is a major mechanism by which potassium and calcium channels increase functional diversity in animals. Extensive alternative splicing of the para sodium channel gene and developmental regulation of alternative splicing have been reported in Drosophila species. Alternative splicing has also been observed for several mammalian voltage-gated sodium channel genes. However, the functional significance of alternative splicing of sodium channels has not been demonstrated. In this study, we identified three mutually exclusive alternative exons encoding part of segments 3 and 4 of domain III in the German cockroach sodium channel gene, para(CSMA). The splice site is conserved in the mouse, fish, and human Na(v)1.6 sodium channel genes, suggesting an ancient origin. One of the alternative exons possesses a stop codon, which would generate a truncated protein with only the first two domains. The splicing variant containing the stop codon is detected only in the PNS, whereas the other two full-size variants were detected in both the PNS and CNS. When expressed in Xenopus oocytes, the two splicing variants produced robust sodium currents, but with different gating properties, whereas the splicing variant with the stop codon did not produce any detectable sodium current. Furthermore, these two functional splicing variants exhibited a striking difference in sensitivity to a pyrethroid insecticide, deltamethrin. Exon swapping partially reversed the channel sensitivity to deltamethrin. Our results therefore provide the first evidence that alternative splicing of a sodium channel gene produces pharmacologically distinct channels.
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Soderlun DM, Lee SH. Point mutations in homology domain II modify the sensitivity of rat Nav1.8 sodium channels to the pyrethroid insecticide cismethrin. Neurotoxicology 2001; 22:755-65. [PMID: 11829409 DOI: 10.1016/s0161-813x(01)00065-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two point mutations in homology domain II of the housefly Vsscl voltage-sensitive sodium channel subunit, M918T and L1014F are associated with resistance to pyrethroid insecticides and reduce the pyrethroid sensitivity of Vsscl sodium channels expressed in Xenopus laevis oocytes. To assess the impact of these residues as determinants of pyrethroid sensitivity in another sequence context, we mutated the corresponding positions of the rat pyrethroid-sensitive, TTX-resistant peripheral nerve sodium channel (rNav1.8; also called SNS or PN3) and determined the sensitivity of native and mutated channels expressed in Xenopus oocytes to the pyrethroid insecticide cismethrin. The rNav1.8 channel, like other vertebrate sodium channel isoforms, contains a conserved isoleucine residue at sequence position 780 that aligns with the conserved methionine at position 918 of Vsscl and other insect sodium channels. Channels mutated to contain methionine at position 780 (1780M) exhibited enhanced sensitivity to cismethrin and larger decay constants for pyrethroid-modified channel states. In contrast, the mutation corresponding to M918Tin the Vssc1 channel (1780T) profoundly decreased the cismethrin sensitivity of expressed channels. Insertion of the mutation corresponding to L1014F (L879F in rNav1.8) reduced the cismethrin sensitivity of channels having either isoleucine or methionine at position 780, whereas channels containing the 1780T/L879F double mutation were insensitive to this insecticide. Mutations at Ile780 and Leu879 also modified the voltage dependence of rNav1.8 channels, but these effects were not related to changes in pyrethroid sensitivity. These results confirm the importance of residues in homology domain II as fundamental determinants of the pyrethroid sensitivity of sodium channels.
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Affiliation(s)
- D M Soderlun
- Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456, USA.
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