1
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Delinière A, Jaupart L, Janin A, Millat G, Boulin T, Andrini O, Chevalier P. Functional and clinical characterization of a novel homozygous KCNH2 missense variant in the pore region of Kv11.1 leading to a viable but severe long-QT syndrome. Gene 2024; 897:148076. [PMID: 38086455 DOI: 10.1016/j.gene.2023.148076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/22/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND Among KCNH2 missense loss of function (LOF) variants, homozygosity -at any position in the Kv11.1/hERG channel - is very rare and generally leads to intrauterine death, while heterozygous variants in the pore are responsible for severe Type 2 long-QT syndrome (LQTS). We report a novel homozygous p.Gly603Ser missense variant in the pore of Kv11.1/hERG (KCNH2 c.1807G > A) discovered in the context of a severe LQTS. METHODS We carried out a phenotypic family study combined with a functional analysis of mutated and wild-type (WT) Kv11.1 by two-electrode voltage-clamp using the Xenopus laevis oocyte heterologous expression system. RESULTS The variant resulted in a severe LQTS phenotype (very prolonged corrected QT interval, T-wave alternans, multiple Torsades de pointes) with a delayed clinical expression in later childhood in the homozygous state, and in a Type 2 LQTS phenotype in the heterozygous state. Expression of KCNH2 p.Gly603Ser cRNA alone elicited detectable current in Xenopus oocytes. Inactivation kinetics and voltage dependence of activation were not significantly affected by the variant. The macroscopic slope conductance of the variant was three-fold less compared to the WT (18.5 ± 9.01 vs 54.7 ± 17.2 μS, p < 0.001). CONCLUSIONS We characterized the novel p.Gly603Ser KCNH2 missense LOF variant in the pore region of Kv11.1/hERG leading to a severe but viable LQTS in the homozygous state and an attenuated Type 2 LQTS in heterozygous carriers. To our knowledge we provide the first description of a homozygous variant in the pore-forming region of Kv11.1 with a functional impact but a delayed clinical expression.
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Affiliation(s)
- Antoine Delinière
- National Reference Center for Inherited Arrhythmias of Lyon, Department of Cardiac Electrophysiology, Louis Pradel Hospital, Hospices Civils de Lyon, Lyon, France; University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France
| | - Laureen Jaupart
- University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France
| | - Alexandre Janin
- University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France; Laboratoire de cardiogénétique moléculaire, Centre de biologie et pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Gilles Millat
- University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France; Laboratoire de cardiogénétique moléculaire, Centre de biologie et pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Thomas Boulin
- University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France
| | - Olga Andrini
- University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France.
| | - Philippe Chevalier
- National Reference Center for Inherited Arrhythmias of Lyon, Department of Cardiac Electrophysiology, Louis Pradel Hospital, Hospices Civils de Lyon, Lyon, France; University of Lyon, Claude Bernard Lyon 1 University, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France.
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2
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Wolfe AD, Koberstein JN, Smith CB, Stewart ML, Gonzalez IJ, Hammarlund M, Hyman AA, Stork PJS, Goodman RH, Colón-Ramos DA. Local and dynamic regulation of neuronal glycolysis in vivo. Proc Natl Acad Sci U S A 2024; 121:e2314699121. [PMID: 38198527 PMCID: PMC10801914 DOI: 10.1073/pnas.2314699121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/01/2023] [Indexed: 01/12/2024] Open
Abstract
Energy metabolism supports neuronal function. While it is well established that changes in energy metabolism underpin brain plasticity and function, less is known about how individual neurons modulate their metabolic states to meet varying energy demands. This is because most approaches used to examine metabolism in living organisms lack the resolution to visualize energy metabolism within individual circuits, cells, or subcellular regions. Here, we adapted a biosensor for glycolysis, HYlight, for use in Caenorhabditis elegans to image dynamic changes in glycolysis within individual neurons and in vivo. We determined that neurons cell-autonomously perform glycolysis and modulate glycolytic states upon energy stress. By examining glycolysis in specific neurons, we documented a neuronal energy landscape comprising three general observations: 1) glycolytic states in neurons are diverse across individual cell types; 2) for a given condition, glycolytic states within individual neurons are reproducible across animals; and 3) for varying conditions of energy stress, glycolytic states are plastic and adapt to energy demands. Through genetic analyses, we uncovered roles for regulatory enzymes and mitochondrial localization in the cellular and subcellular dynamic regulation of glycolysis. Our study demonstrates the use of a single-cell glycolytic biosensor to examine how energy metabolism is distributed across cells and coupled to dynamic states of neuronal function and uncovers unique relationships between neuronal identities and metabolic landscapes in vivo.
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Affiliation(s)
- Aaron D. Wolfe
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06536
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06536
| | | | - Chadwick B. Smith
- Vollum Institute, Oregon Health & Science University, Portland, OR97239
| | | | - Ian J. Gonzalez
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06536
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06536
| | - Marc Hammarlund
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06536
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06536
| | - Anthony A. Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden01307, Germany
| | | | - Richard H. Goodman
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06536
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06536
- Vollum Institute, Oregon Health & Science University, Portland, OR97239
| | - Daniel A. Colón-Ramos
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06536
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06536
- Wu Tsai Institute, Yale University, New Haven, CT06510
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3
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Florin F, Bonneau B, Briseño-Roa L, Bessereau JL, Jospin M. Calcineurin-Dependent Homeostatic Response of C. elegans Muscle Cells upon Prolonged Activation of Acetylcholine Receptors. Cells 2023; 12:2201. [PMID: 37681933 PMCID: PMC10486475 DOI: 10.3390/cells12172201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023] Open
Abstract
Pharmacological adaptation is a common phenomenon observed during prolonged drug exposure and often leads to drug resistance. Understanding the cellular events involved in adaptation could provide new strategies to circumvent this resistance issue. We used the nematode Caenorhabditis elegans to analyze the adaptation to levamisole, an ionotropic acetylcholine receptor agonist, used for decades to treat nematode parasitic infections. Genetic screens in C. elegans identified "adapting mutants" that initially paralyze upon exposure to levamisole as the wild type (WT), but recover locomotion after a few hours whereas WT remain paralyzed. Here, we show that levamisole induces a sustained increase in cytosolic calcium concentration in the muscle cells of adapting mutants, lasting several hours and preceding a decrease in levamisole-sensitive acetylcholine receptors (L-AChR) at the muscle plasma membrane. This decrease correlated with a drop in calcium concentration, a relaxation of the animal's body and a resumption of locomotion. The decrease in calcium and L-AChR content depends on calcineurin activation in muscle cells. We also showed that levamisole adaptation triggers homeostatic mechanisms in muscle cells including mitochondria remodeling, lysosomal tubulation and an increase in autophagic activity. Levamisole adaptation thus provides a new experimental paradigm for studying how cells cope with calcium stress.
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Affiliation(s)
- Franklin Florin
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
| | - Benjamin Bonneau
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
- Institut Curie, CNRS UMR3347, INSERM U1021, Université Paris-Saclay, F-91405 Orsay, France
| | - Luis Briseño-Roa
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
- Medetia Pharmaceuticals, Institut Imagine, F-75015 Paris, France
| | - Jean-Louis Bessereau
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
| | - Maëlle Jospin
- Institut NeuroMyoGène, CNRS UMR-5284, INSERM U-1314, MeLiS, Université Lyon, Université Claude Bernard Lyon 1, F-69008 Lyon, France (B.B.); (J.-L.B.)
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4
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Noonan JD, Beech RN. Two residues determine nicotinic acetylcholine receptor requirement for RIC-3. Protein Sci 2023; 32:e4718. [PMID: 37417463 PMCID: PMC10443321 DOI: 10.1002/pro.4718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/11/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023]
Abstract
Nicotinic acetylcholine receptors (N-AChRs) mediate fast synaptic signaling and are members of the pentameric ligand-gated ion channel (pLGIC) family. They rely on a network of accessory proteins in vivo for correct formation and transport to the cell surface. Resistance to cholinesterase 3 (RIC-3) is an endoplasmic reticulum protein that physically interacts with nascent pLGIC subunits and promotes their oligomerization. It is not known why some N-AChRs require RIC-3 in heterologous expression systems, whereas others do not. Previously we reported that the ACR-16 N-AChR from the parasitic nematode Dracunculus medinensis does not require RIC-3 in Xenopus laevis oocytes. This is unusual because all other nematode ACR-16, like the closely related Ascaris suum ACR-16, require RIC-3. Their high sequence similarity limits the number of amino acids that may be responsible, and the goal of this study was to identify them. A series of chimeras and point mutations between A. suum and D. medinensis ACR-16, followed by functional characterization with electrophysiology, identified two residues that account for a majority of the receptor requirement for RIC-3. ACR-16 with R/K159 in the cys-loop and I504 in the C-terminal tail did not require RIC-3 for functional expression. Mutating either of these to R/K159E or I504T, residues found in other nematode ACR-16, conferred a RIC-3 requirement. Our results agree with previous studies showing that these regions interact and are involved in receptor synthesis. Although it is currently unclear what precise mechanism they regulate, these residues may be critical during specific subunit folding and/or assembly cascades that RIC-3 may promote.
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Affiliation(s)
- Jennifer D. Noonan
- Institute of Parasitology, Macdonald Campus, McGill UniversityMontrealQuébecCanada
| | - Robin N. Beech
- Institute of Parasitology, Macdonald Campus, McGill UniversityMontrealQuébecCanada
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5
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Wolfe AD, Koberstein JN, Smith CB, Stewart ML, Hammarlund M, Hyman A, Stork PJ, Goodman R, Colón-Ramos DA. Local and dynamic regulation of neuronal glycolysis in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.25.554774. [PMID: 37662365 PMCID: PMC10473759 DOI: 10.1101/2023.08.25.554774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Energy metabolism supports neuronal function. While it is well established that changes in energy metabolism underpin brain plasticity and function, less is known about how individual neurons modulate their metabolic states to meet varying energy demands. This is because most approaches used to examine metabolism in living organisms lack the resolution to visualize energy metabolism within individual circuits, cells, or subcellular regions. Here we adapted a biosensor for glycolysis, HYlight, for use in C. elegans to image dynamic changes in glycolysis within individual neurons and in vivo. We determined that neurons perform glycolysis cell-autonomously, and modulate glycolytic states upon energy stress. By examining glycolysis in specific neurons, we documented a neuronal energy landscape comprising three general observations: 1) glycolytic states in neurons are diverse across individual cell types; 2) for a given condition, glycolytic states within individual neurons are reproducible across animals; and 3) for varying conditions of energy stress, glycolytic states are plastic and adapt to energy demands. Through genetic analyses, we uncovered roles for regulatory enzymes and mitochondrial localization in the cellular and subcellular dynamic regulation of glycolysis. Our study demonstrates the use of a single-cell glycolytic biosensor to examine how energy metabolism is distributed across cells and coupled to dynamic states of neuronal function, and uncovers new relationships between neuronal identities and metabolic landscapes in vivo.
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Affiliation(s)
- Aaron D Wolfe
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - John N Koberstein
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Chadwick B Smith
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Melissa L Stewart
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Marc Hammarlund
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Anthony Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden, Germany
| | - Philip Js Stork
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Richard Goodman
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Daniel A Colón-Ramos
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
- Wu Tsai Institute, Yale University; New Haven, CT 06510, USA
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6
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Hernando G, Turani O, Rodriguez Araujo N, Bouzat C. The diverse family of Cys-loop receptors in Caenorhabditis elegans: insights from electrophysiological studies. Biophys Rev 2023; 15:733-750. [PMID: 37681094 PMCID: PMC10480131 DOI: 10.1007/s12551-023-01080-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/18/2023] [Indexed: 09/09/2023] Open
Abstract
Cys-loop receptors integrate a large family of pentameric ligand-gated ion channels that mediate fast ionotropic responses in vertebrates and invertebrates. Their vital role in converting neurotransmitter recognition into an electrical impulse makes these receptors essential for a great variety of physiological processes. In vertebrates, the Cys-loop receptor family includes the cation-selective channels, nicotinic acetylcholine and 5-hydroxytryptamine type 3 receptors, and the anion-selective channels, GABAA and glycine receptors, whereas in invertebrates, the repertoire is significantly larger. The free-living nematode Caenorhabditis elegans has the largest known Cys-loop receptor family as well as unique receptors that are absent in vertebrates and constitute attractive targets for anthelmintic drugs. Given the large number and variety of Cys-loop receptor subunits and the multiple possible ways of subunit assembly, C. elegans offers a large diversity of receptors although only a limited number of them have been characterized to date. C. elegans has emerged as a powerful model for the study of the nervous system and human diseases as well as a model for antiparasitic drug discovery. This nematode has also shown promise in the pharmaceutical industry search for new therapeutic compounds. C. elegans is therefore a powerful model organism to explore the biology and pharmacology of Cys-loop receptors and their potential as targets for novel therapeutic interventions. In this review, we provide a comprehensive overview of what is known about the function of C. elegans Cys-loop receptors from an electrophysiological perspective.
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Affiliation(s)
- Guillermina Hernando
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Ornella Turani
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Noelia Rodriguez Araujo
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
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7
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Courtot É, Miclon M, Reaves B, Wolstenholme AJ, Neveu C. Functional validation of the truncated UNC-63 acetylcholine receptor subunit in levamisole resistance. Int J Parasitol 2023:S0020-7519(23)00051-6. [PMID: 36965824 DOI: 10.1016/j.ijpara.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 03/27/2023]
Abstract
Levamisole is a broad-spectrum anthelmintic which permanently activates cholinergic receptors from nematodes, inducing a spastic paralysis of the worms. Whereas this molecule is widely used to control parasitic nematodes impacting livestock, its efficacy is compromised by the emergence of drug-resistant parasites. In that respect, there is an urgent need to identify and validate molecular markers associated with resistance. Previous transcriptomic analyses revealed truncated cholinergic receptor subunits as potential levamisole resistance markers in the trichostrongylid nematodes Haemonchus contortus, Telodorsagia circumcincta and Trichostrongylus colubriformis. In the present study we used the Xenopus oocyte, as well as the free-living model nematode Caenorhabditis elegans, as heterologous expression systems to functionally investigate truncated isoforms of the levamisole-sensitive acetylcholine receptor (L-AChR) UNC-63 subunit. In the Xenopus oocyte, we report that truncated UNC-63 from C. elegans has a strong dominant negative effect on the expression of the recombinant C. elegans L-AChRs. In addition, we show that when expressed in C. elegans muscle cells, truncated UNC-63 induces a drastic reduction in levamisole susceptibility in transgenic worms, thus providing the first known functional validation for this molecular marker in vivo.
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Affiliation(s)
- Élise Courtot
- Infectiologie et Santé Publique, INRAE, Université de Tours, UMR 1282, 37380, Nouzilly, France.
| | - Morgane Miclon
- Infectiologie et Santé Publique, INRAE, Université de Tours, UMR 1282, 37380, Nouzilly, France
| | - Barbara Reaves
- Infectiologie et Santé Publique, INRAE, Université de Tours, UMR 1282, 37380, Nouzilly, France
| | - Adrian J Wolstenholme
- Infectiologie et Santé Publique, INRAE, Université de Tours, UMR 1282, 37380, Nouzilly, France
| | - Cédric Neveu
- Infectiologie et Santé Publique, INRAE, Université de Tours, UMR 1282, 37380, Nouzilly, France.
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8
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Mizumoto K, Jin Y, Bessereau JL. Synaptogenesis: unmasking molecular mechanisms using Caenorhabditis elegans. Genetics 2023; 223:iyac176. [PMID: 36630525 PMCID: PMC9910414 DOI: 10.1093/genetics/iyac176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/22/2022] [Indexed: 01/13/2023] Open
Abstract
The nematode Caenorhabditis elegans is a research model organism particularly suited to the mechanistic understanding of synapse genesis in the nervous system. Armed with powerful genetics, knowledge of complete connectomics, and modern genomics, studies using C. elegans have unveiled multiple key regulators in the formation of a functional synapse. Importantly, many signaling networks display remarkable conservation throughout animals, underscoring the contributions of C. elegans research to advance the understanding of our brain. In this chapter, we will review up-to-date information of the contribution of C. elegans to the understanding of chemical synapses, from structure to molecules and to synaptic remodeling.
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Affiliation(s)
- Kota Mizumoto
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z3, Canada
| | - Yishi Jin
- Department of Neurobiology, University of California San Diego, La Jolla, CA 92093, USA
| | - Jean-Louis Bessereau
- Univ Lyon, University Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U 1314, Melis, 69008 Lyon, France
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9
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Multivariate chemogenomic screening prioritizes new macrofilaricidal leads. Commun Biol 2023; 6:44. [PMID: 36639423 PMCID: PMC9839782 DOI: 10.1038/s42003-023-04435-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023] Open
Abstract
Development of direct acting macrofilaricides for the treatment of human filariases is hampered by limitations in screening throughput imposed by the parasite life cycle. In vitro adult screens typically assess single phenotypes without prior enrichment for chemicals with antifilarial potential. We developed a multivariate screen that identified dozens of compounds with submicromolar macrofilaricidal activity, achieving a hit rate of >50% by leveraging abundantly accessible microfilariae. Adult assays were multiplexed to thoroughly characterize compound activity across relevant parasite fitness traits, including neuromuscular control, fecundity, metabolism, and viability. Seventeen compounds from a diverse chemogenomic library elicited strong effects on at least one adult trait, with differential potency against microfilariae and adults. Our screen identified five compounds with high potency against adults but low potency or slow-acting microfilaricidal effects, at least one of which acts through a novel mechanism. We show that the use of microfilariae in a primary screen outperforms model nematode developmental assays and virtual screening of protein structures inferred with deep learning. These data provide new leads for drug development, and the high-content and multiplex assays set a new foundation for antifilarial discovery.
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10
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Izquierdo PG, Charvet CL, Neveu C, Green AC, Tattersall JEH, Holden-Dye L, O'Connor V. Modelling organophosphate intoxication in C. elegans highlights nicotinic acetylcholine receptor determinants that mitigate poisoning. PLoS One 2023; 18:e0284786. [PMID: 37083685 PMCID: PMC10121051 DOI: 10.1371/journal.pone.0284786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 04/06/2023] [Indexed: 04/22/2023] Open
Abstract
Organophosphate intoxication via acetylcholinesterase inhibition executes neurotoxicity via hyper stimulation of acetylcholine receptors. Here, we use the organophosphate paraoxon-ethyl to treat C. elegans and use its impact on pharyngeal pumping as a bio-assay to model poisoning through these neurotoxins. This assay provides a tractable measure of acetylcholine receptor mediated contraction of body wall muscle. Investigation of the time dependence of organophosphate treatment and the genetic determinants of the drug-induced inhibition of pumping highlight mitigating modulation of the effects of paraoxon-ethyl. We identified mutants that reduce acetylcholine receptor function protect against the consequence of intoxication by organophosphates. Data suggests that reorganization of cholinergic signalling is associated with organophosphate poisoning. This reinforces the under investigated potential of using therapeutic approaches which target a modulation of nicotinic acetylcholine receptor function to treat the poisoning effects of this important class of neurotoxins.
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Affiliation(s)
- Patricia G Izquierdo
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Claude L Charvet
- French National Institute for Agricultural Research (INRA), Infectiologie Animale et Santé Publique, Nouzilly, France
| | - Cedric Neveu
- French National Institute for Agricultural Research (INRA), Infectiologie Animale et Santé Publique, Nouzilly, France
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Vincent O'Connor
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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11
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Espejo L, Hull B, Chang LM, DeNicola D, Freitas S, Silbar V, Haskins A, Turner EA, Sutphin GL. Long-Term Culture of Individual Caenorhabditis elegans on Solid Media for Longitudinal Fluorescence Monitoring and Aversive Interventions. J Vis Exp 2022:10.3791/64682. [PMID: 36533827 PMCID: PMC10368144 DOI: 10.3791/64682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
Caenorhabditis elegans are widely used to study aging biology. The standard practice in C. elegans aging studies is to culture groups of worms on solid nematode growth media (NGM), allowing the efficient collection of population-level data for survival and other physiological phenotypes, and periodic sampling of subpopulations for fluorescent biomarker quantification. Limitations to this approach are the inability to (1) follow individual worms over time to develop age trajectories for phenotypes of interest and (2) monitor fluorescent biomarkers directly in the context of the culture environment. Alternative culture approaches use liquid culture or microfluidics to monitor individual animals over time, in some cases including fluorescence quantification, with the tradeoff that the culture environment is contextually distinct from solid NGM. The WorMotel is a previously described microfabricated multi-well device for culturing isolated worms on solid NGM. Each worm is maintained in a well containing solid NGM surrounded by a moat filled with copper sulfate, a contact repellent for C. elegans, allowing longitudinal monitoring of individual animals. We find copper sulfate insufficient to prevent worms from fleeing when subjected to aversive interventions common in aging research, including dietary restriction, pathogenic bacteria, and chemical agents that induce cellular stress. The multi-well devices are also molded from polydimethylsiloxane, which produces high background artifacts in fluorescence imaging. This protocol describes a new approach for culturing isolated roundworms on solid NGM using commercially available polystyrene microtrays, originally designed for human leukocyte antigen (HLA) typing, allowing the measurement of survival, physiological phenotypes, and fluorescence across the lifespan. A palmitic acid barrier prevents worms from fleeing, even in the presence of aversive conditions. Each plate can culture up to 96 animals and easily adapts to a variety of conditions, including dietary restriction, RNAi, and chemical additives, and is compatible with automated systems for collecting lifespan and activity data.
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Affiliation(s)
- Luis Espejo
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Bradford Hull
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Leah M Chang
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Destiny DeNicola
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Samuel Freitas
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Vanessa Silbar
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Anne Haskins
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - Emily A Turner
- Department of Molecular & Cellular Biology, University of Arizona, Tucson
| | - George L Sutphin
- Department of Molecular & Cellular Biology, University of Arizona, Tucson;
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12
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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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13
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Reconstitution of an N-AChR from Brugia malayi an evolved change in acetylcholine receptor accessory protein requirements in filarial parasites. PLoS Pathog 2022; 18:e1010962. [DOI: 10.1371/journal.ppat.1010962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 12/01/2022] [Accepted: 10/29/2022] [Indexed: 11/15/2022] Open
Abstract
Neurotransmission is an important target for anthelmintic drugs, where receptor characteristics and response can be examined through reconstitution ex vivo in Xenopus laevis oocytes. The homomeric ACR-16 nicotine sensitive acetylcholine receptors (N-AChRs) of several helminth species have been characterized in this way. Our efforts to reconstitute the N-AChR from the clade III filarial parasite, Brugia malayi using similar conditions, initially produced no detectable response. A robust response to acetylcholine is obtained from the closely related clade III parasite Ascaris suum, suggesting that specific changes have occurred between Ascaris and Brugia. N-AChRs from three species intermediate between A. suum and B. malayi were characterized to provide information on the cause. Maximal response to acetylcholine did not change abruptly, consistent with a discrete event, but rather decreased progressively from A. suum through Dracunculus medinensis, Gonglylonema pulchrum and Thelazia callipaeda. Receptor responses to the characteristic nicotine, and other agonists were generally similar. The decrease in maximal current did correlate with a delayed time to reach larger response. Together, this suggested that the failure to reconstitute the B. malayi N-AChR was one extreme of a progressive decrease and that an issue with synthesis of the receptor in oocytes was responsible. Addition of accessory proteins EMC-6, NRA-2 and NRA-4, in addition to RIC-3, produced a small, but measurable B. malayi N-AChR response. Pharmacological properties of a chimeric B. malayi N-AChR were equivalent to the other species, confirming the receptor response remains unchanged while its production is increasingly dependent on accessory proteins. One possibility is that loss of many subunits for acetylcholine receptors from the filarial nematode genome is linked to new subunit combinations that lead to such a dependence. This novel phylogenetic approach allowed the first characterization of a B. malayi AChR ex vivo and in doing so, provides a framework for the successful characterization of other receptors that have yet to be reconstituted.
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14
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Nguyen VT, Park AR, Duraisamy K, Vo DD, Kim JC. Elucidation of the nematicidal mode of action of grammicin on Caenorhabditis elegans. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 188:105244. [PMID: 36464355 DOI: 10.1016/j.pestbp.2022.105244] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/05/2022] [Accepted: 09/13/2022] [Indexed: 06/17/2023]
Abstract
Grammicin (Gra) is derived from the endophytic fungus Xylaria grammica EL000614 and shows nematicidal activity against the devastating root-knot nematode Meloidogyne incognita in-vitro, in planta, and in-field experiments. However, the mechanism of the nematicidal action of Gra remains unclear. In this study, Gra exposure to the model genetic organism Caenorhabditis elegans affected its L1, L2/3, L4, and young adult stages. In addition, Gra treatment increased the intracellular reactive oxygen species (ROS) levels of C. elegans and M. incognita. Molecular docking interaction analysis indicated that Gra could bind and interact with GCS-1, GST-4, and DAF-16a in order of low binding energy, followed by SOD-3, SKN-1, and DAF-16b. This implies that the anthelmintic action of Gra is related to the oxidative stress response. To validate this mechanism, we examined the expression of the genes involved in the oxidative stress responses following treatment with Gra using transgenic C. elegans strains such as the TJ356 strain zIs356 [daf-16p::daf-16a/b::GFP + rol-6 (su1006)], LD1 ldIs7 [skn-1p::skn-1b/c::GFP + rol-6 (su1006)], LD1171 ldIs3 [gcs-1p::GFP + rol-6 (su1006)], CL2166 dvIs19 [(pAF15) gst-4p::GFP::NLS], and CF1553 strain muIs84 [(pAD76) sod-3p::GFP + rol-6 (su1006)]. Gra treatment caused nuclear translocation of DAF-16/FoxO and enhanced gst-4::GFP expression, but it had no change in sod-3::GFP expression. These results indicate that Gra induces oxidative stress response via phase II detoxification without reduced cellular redox machinery. Gra treatment also inhibited the nuclear localization of SKN-1::GFP in the intestine, which may lead to a condition in which oxidative stress tolerance is insufficient to protect C. elegans by the inactivation of SKN-1, thus inducing nematode lethality. Furthermore, Gra caused the mortality of two mutant strains of C. elegans, CB113 and DA1316, which are resistant to aldicarb and ivermectin, respectively. This indicates that the mode of action of Gra is different from the traditional nematicides currently in use, suggesting that it could help develop novel approaches to control plant-parasitic nematodes.
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Affiliation(s)
- Van Thi Nguyen
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Ae Ran Park
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kalaiselvi Duraisamy
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Duc Duy Vo
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, SE-75124 Uppsala, Sweden
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea.
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15
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Sattelle DB. Invertebrate neurones, genomes, phenotypic and target-based screening; their contributions to the search for new chemical leads and new molecular targets for the control of pests, parasites and disease vectors. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 187:105175. [PMID: 36127074 DOI: 10.1016/j.pestbp.2022.105175] [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: 04/26/2022] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Insect-borne diseases of humans, animals and plants can be devastating. The direct damage to crops by insect and nematode pests can also severely reduce crop yields and threaten harvests. Parasitic nematodes can impair human health and the health of farm livestock. Effective control for all such pests, vectors and pathogens is required as the economic and health burden can be substantial. Insecticides, nematicides and anthelmintics have been at the forefront of control and will remain important in the immediate future, even as we explore new and more sustainable methods to maintain the necessary disease control and the growth in food supply. Many important chemicals deployed for the control of invertebrate disease vectors and pathogens of humans, agricultural crops and farm livestock are active on ion channels, resulting in rapid actions. Understanding their modes of action has been accelerated by studies on the physiology of identifiable invertebrate excitable cells. Nematode and insect genetic model organisms and comparative genomics have contributed to defining the molecular targets of insecticides and anthelmintics, facilitating target-based screening. Automated phenotyping, which allows high-throughput screening of chemical libraries for new and re-purposed compounds, has been increasingly deployed in the search for new molecules of interest. With a growing world population to be fed and a 20-49% loss of global harvest to pests, we need to maintain control of the pests, parasites and pathogens that threaten global food supply and global health.
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Affiliation(s)
- David B Sattelle
- Division of Medicine, Rayne Building, University College London, 5 University Street, London WC1E 6JF, UK.
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16
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Brunello L, Ménard C, Rousset M, Vignes M, Charnet P, Cens T. Different efficiency of auxiliary/chaperone proteins to promote the functional reconstitution of honeybee glutamate and acetylcholine receptors in Xenopus laevis oocytes. INSECT MOLECULAR BIOLOGY 2022; 31:620-633. [PMID: 35587772 PMCID: PMC9546428 DOI: 10.1111/imb.12791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Heterologous expression systems (e.g., Xenopus laevis oocytes) are useful to study the biophysical properties and pharmacology of ionotropic receptors such as ionotropic glutamate (iGLuRs) and nicotinic acetylcholine (nAChRs) receptors. However, insect receptors often require the co-expression of chaperone proteins to be functional. Only few iGluRs and nAChRs have been successfully expressed in such systems. Here, we compared the efficiency of chaperone proteins to promote the functional expression of one Apis mellifera iGluR and several nAChR subunit combinations (α1α8β1, α7, α2α8β1 and α2α7α8β1) in Xenopus oocytes. To this end, we cloned a new iGluR (GluR-1) and potential chaperone proteins (e.g., SOL-1, Neto, NACHO) and tested more than 40 combinations of human, nematode and honeybee proteins. We obtained robust expression of GluR-1 and α1α8β1 when co-expressed with honeybee chaperone proteins and found that nAChR expression critically depended on the α1 subunit N-terminal sequence. We recorded small ACh-gated currents in few oocytes when the α7 subunit was co-expressed with Caenorhabditis elegans RIC-3, but none of the chaperone proteins allowed efficient expression of α2α8β1 or α2α7α8β1. Our results show that only some protein combinations can reconstitute functional receptors in Xenopus oocytes and that protein combination efficient in one species is not always efficient in another species.
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Affiliation(s)
- Lorène Brunello
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
| | - Claudine Ménard
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
| | - Matthieu Rousset
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
| | - Michel Vignes
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
| | - Pierre Charnet
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
| | - Thierry Cens
- Intitut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCMMontpellierFrance
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17
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Calahorro F, Chapman M, Dudkiewicz K, Holden-Dye L, O'Connor V. PharmacoGenetic targeting of a C. elegans essential neuron provides an in vivo screening for novel modulators of nematode ion channel function. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 186:105152. [PMID: 35973757 DOI: 10.1016/j.pestbp.2022.105152] [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: 02/28/2022] [Revised: 05/18/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Chemical or drug treatments are successfully used to treat parasitic nematode infections that impact human, animal and plant health. Many of these exert their effects through modifying neural function underpinning behaviours essential for parasite viability. Selectivity against the parasite may be achieved through distinct pharmacological properties of the parasite nervous system, as exemplified by the success of the ivermectin which target a glutamate-gated chloride channel found only in invertebrates. Despite the success of the ivermectins, emerging resistance and concerns around eco-toxicity are driving the search for new nematocidal chemicals or drugs. Here, we describe the potential of a 5-HT-gated chloride channel MOD-1, which is involved in vital parasite behaviours with constrained distribution in the invertebrate phyla. This ion channel has potential pharmacophores that could be targeted by new nematocidal chemicals and drugs. We have developed a microtiter based bioassay for MOD-1 pharmacology based on its ectopic expression in the Caenorhabditis elegans essential neuron M4. We have termed this technology 'PhaGeM4' for 'Pharmacogenetic targeting of M4 neuron'. Exposure of transgenic worms harbouring ectopically expressed MOD-1 to 5-HT results in developmental arrest. By additional expression of a fluorescence marker in body wall muscle to monitor growth we demonstrate that this assay is suitable for the identification of receptor agonists and antagonists. Indeed, the developmental progression is a robustly quantifiable bioassay that resolves MOD-1 activation by quipazine, 5-carboxyamidotryptamine and fluoxetine and highlight methiothepin as a potent antagonist. This assay has the intrinsic ability to highlight compounds with optimal bioavailability and furthermore to filter out off-target effects. It can be extended to the investigation of other classes of membrane receptors and modulators of neuronal excitation. This approach based on heterologous modulation of the essential M4 neuron function offers a route to discover new effective and selective anthelmintics potentially less confounded by disruptive environmental impact.
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Affiliation(s)
- Fernando Calahorro
- School of Biological Sciences, University of Southampton, Life Sciences Building 85, Southampton SO17 1BJ, UK.
| | - Mark Chapman
- School of Biological Sciences, University of Southampton, Life Sciences Building 85, Southampton SO17 1BJ, UK
| | - Katarzyna Dudkiewicz
- School of Biological Sciences, University of Southampton, Life Sciences Building 85, Southampton SO17 1BJ, UK
| | - Lindy Holden-Dye
- School of Biological Sciences, University of Southampton, Life Sciences Building 85, Southampton SO17 1BJ, UK
| | - Vincent O'Connor
- School of Biological Sciences, University of Southampton, Life Sciences Building 85, Southampton SO17 1BJ, UK
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18
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An extracellular scaffolding complex confers unusual rectification upon an ionotropic acetylcholine receptor in C. elegans. Proc Natl Acad Sci U S A 2022; 119:e2113545119. [PMID: 35858330 PMCID: PMC9304021 DOI: 10.1073/pnas.2113545119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Biophysical properties of ligand-gated receptors can be profoundly modified by auxiliary subunits or by the lipid microenvironment of the membrane. Hence, it is sometimes challenging to relate the properties of receptors reconstituted in heterologous expression systems to those of their native counterparts. Here we show that the properties of Caenorhabditis elegans levamisole-sensitive acetylcholine receptors (L-AChRs), the ionotropic acetylcholine receptors targeted by the cholinergic anthelmintic levamisole at neuromuscular junctions, can be profoundly modified by their clustering machinery. We uncovered that L-AChRs exhibit a strong outward rectification in vivo, which was not previously described in heterologous systems. This unusual feature for an ionotropic AChR is abolished by disrupting the interaction of the receptors with the extracellular complex required for their synaptic clustering. When recorded at -60 mV, levamisole-induced currents are similar in the wild type and in L-AChR-clustering-defective mutants, while they are halved in these mutants at more depolarized physiological membrane potentials. Consequently, levamisole causes a strong muscle depolarization in the wild type, which leads to complete inactivation of the voltage-gated calcium channels and to an irreversible flaccid paralysis. In mutants defective for L-AChR clustering, the levamisole-induced depolarization is weaker, allowing voltage-gated calcium channels to remain partially active, which eventually leads to adaptation and survival of the worms. This explains why historical screens for C. elegans mutants resistant to levamisole identified the components of the L-AChR clustering machinery, in addition to proteins required for receptor biosynthesis or efficacy. This work further emphasizes the importance of pursuing ligand-gated channel characterization in their native environment.
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19
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Rispe C, Hervet C, de la Cotte N, Daveu R, Labadie K, Noel B, Aury JM, Thany S, Taillebois E, Cartereau A, Le Mauff A, Charvet CL, Auger C, Courtot E, Neveu C, Plantard O. Transcriptome of the synganglion in the tick Ixodes ricinus and evolution of the cys-loop ligand-gated ion channel family in ticks. BMC Genomics 2022; 23:463. [PMID: 35733088 PMCID: PMC9219234 DOI: 10.1186/s12864-022-08669-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/27/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ticks represent a major health issue for humans and domesticated animals. Exploring the expression landscape of the tick's central nervous system (CNS), known as the synganglion, would be an important step in understanding tick physiology and in managing tick-borne diseases, but studies on that topic are still relatively scarce. Neuron-specific genes like the cys-loop ligand-gated ion channels (cys-loop LGICs, or cysLGICs) are important pharmacological targets of acaricides. To date their sequence have not been well catalogued for ticks, and their phylogeny has not been fully studied. RESULTS We carried out the sequencing of transcriptomes of the I. ricinus synganglion, for adult ticks in different conditions (unfed males, unfed females, and partially-fed females). The de novo assembly of these transcriptomes allowed us to obtain a large collection of cys-loop LGICs sequences. A reference meta-transcriptome based on synganglion and whole body transcriptomes was then produced, showing high completeness and allowing differential expression analyses between synganglion and whole body. Many of the genes upregulated in the synganglion were associated with neurotransmission and/or localized in neurons or the synaptic membrane. As the first step of a functional study of cysLGICs, we cloned the predicted sequence of the resistance to dieldrin (RDL) subunit homolog, and functionally reconstituted the first GABA-gated receptor of Ixodes ricinus. A phylogenetic study was performed for the nicotinic acetylcholine receptors (nAChRs) and other cys-loop LGICs respectively, revealing tick-specific expansions of some types of receptors (especially for Histamine-like subunits and GluCls). CONCLUSIONS We established a large catalogue of genes preferentially expressed in the tick CNS, including the cysLGICs. We discovered tick-specific gene family expansion of some types of cysLGIC receptors, and a case of intragenic duplication, suggesting a complex pattern of gene expression among different copies or different alternative transcripts of tick neuro-receptors.
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Affiliation(s)
| | | | | | - Romain Daveu
- INRAE, Oniris, BIOEPAR, Nantes, France.,Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Karine Labadie
- Génomique Métabolique, Genoscope, Institut de biologie François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, Evry, France
| | - Benjamin Noel
- Génomique Métabolique, Genoscope, Institut de biologie François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, Evry, France
| | - Jean-Marc Aury
- Génomique Métabolique, Genoscope, Institut de biologie François Jacob, CEA, CNRS, Université d'Evry, Université Paris-Saclay, Evry, France
| | - Steeve Thany
- Université d'Orléans, LBLGC USC INRAE 1328, 1 rue de Chartres, 45067, Orléans, France
| | - Emiliane Taillebois
- Université d'Orléans, LBLGC USC INRAE 1328, 1 rue de Chartres, 45067, Orléans, France
| | - Alison Cartereau
- Université d'Orléans, LBLGC USC INRAE 1328, 1 rue de Chartres, 45067, Orléans, France
| | - Anaïs Le Mauff
- Université d'Orléans, LBLGC USC INRAE 1328, 1 rue de Chartres, 45067, Orléans, France
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20
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Choudhary S, Kashyap SS, Martin RJ, Robertson AP. Advances in our understanding of nematode ion channels as potential anthelmintic targets. Int J Parasitol Drugs Drug Resist 2022; 18:52-86. [PMID: 35149380 PMCID: PMC8841521 DOI: 10.1016/j.ijpddr.2021.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/15/2022]
Abstract
Ion channels are specialized multimeric proteins that underlie cell excitability. These channels integrate with a variety of neuromuscular and biological functions. In nematodes, the physiological behaviors including locomotion, navigation, feeding and reproduction, are regulated by these protein entities. Majority of the antinematodal chemotherapeutics target the ion channels to disrupt essential biological functions. Here, we have summarized current advances in our understanding of nematode ion channel pharmacology. We review cys-loop ligand gated ion channels (LGICs), including nicotinic acetylcholine receptors (nAChRs), acetylcholine-chloride gated ion channels (ACCs), glutamate-gated chloride channels (GluCls), and GABA (γ-aminobutyric acid) receptors, and other ionotropic receptors (transient receptor potential (TRP) channels and potassium ion channels). We have provided an update on the pharmacological properties of these channels from various nematodes. This article catalogs the differences in ion channel composition and resulting pharmacology in the phylum Nematoda. This diversity in ion channel subunit repertoire and pharmacology emphasizes the importance of pursuing species-specific drug target research. In this review, we have provided an overview of recent advances in techniques and functional assays available for screening ion channel properties and their application.
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Affiliation(s)
- Shivani Choudhary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Sudhanva S Kashyap
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
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21
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Wolstenholme AJ, Neveu C. The avermectin/milbemycin receptors of parasitic nematodes. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 181:105010. [PMID: 35082033 DOI: 10.1016/j.pestbp.2021.105010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/24/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Glutamate-gated chloride channels are the most important target of ivermectin and related compounds in parasitic nematodes. A small family of genes encode subunits of these channels, allowing the assembly of multiple channel subtypes; the subunit composition of most of the native receptors is unknown. The members of the gene family vary between species, making extrapolation from C. elegans to parasites difficult. Expression of recombinant receptors in Xenopus oocytes can identify subunits that have the ability to co-assemble into novel channels, but localisation data, ideally at the single-cell level, is required to confirm that these subunits are expressed in the same cells and tissues. Fortunately, recent advances in this area are starting to make this information available; this information is adding to our understanding of how the drugs act and of the possible subunit combinations that create their targets in vivo.
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Affiliation(s)
- Adrian J Wolstenholme
- UMR1282 Infectiologie et Santé Publique, INRAE Centre Val de Loire, 37380 Nouzilly, France.
| | - Cedric Neveu
- UMR1282 Infectiologie et Santé Publique, INRAE Centre Val de Loire, 37380 Nouzilly, France.
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22
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Hansen TVA, Sager H, Toutain CE, Courtot E, Neveu C, Charvet CL. The Caenorhabditis elegans DEG-3/DES-2 Channel Is a Betaine-Gated Receptor Insensitive to Monepantel. Molecules 2022; 27:312. [PMID: 35011544 PMCID: PMC8747062 DOI: 10.3390/molecules27010312] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/31/2021] [Accepted: 01/02/2022] [Indexed: 11/24/2022] Open
Abstract
Natural plant compounds, such as betaine, are described to have nematocidal properties. Betaine also acts as a neurotransmitter in the free-living model nematode Caenorhabditis elegans, where it is required for normal motility. Worm motility is mediated by nicotinic acetylcholine receptors (nAChRs), including subunits from the nematode-specific DEG-3 group. Not all types of nAChRs in this group are associated with motility, and one of these is the DEG-3/DES-2 channel from C. elegans, which is involved in nociception and possibly chemotaxis. Interestingly, the activity of DEG-3/DES-2 channel from the parasitic nematode of ruminants, Haemonchus contortus, is modulated by monepantel and its sulfone metabolite, which belong to the amino-acetonitrile derivative anthelmintic drug class. Here, our aim was to advance the pharmacological knowledge of the DEG-3/DES-2 channel from C. elegans by functionally expressing the DEG-3/DES-2 channel in Xenopus laevis oocytes and using two-electrode voltage-clamp electrophysiology. We found that the DEG-3/DES-2 channel was more sensitive to betaine than ACh and choline, but insensitive to monepantel and monepantel sulfone when used as direct agonists and as allosteric modulators in co-application with betaine. These findings provide important insight into the pharmacology of DEG-3/DES-2 from C. elegans and highlight the pharmacological differences between non-parasitic and parasitic nematode species.
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Affiliation(s)
- Tina V. A. Hansen
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (T.V.A.H.); (E.C.); (C.N.)
| | - Heinz Sager
- Elanco Animal Health Inc., CH-4058 Basel, Switzerland;
| | | | - Elise Courtot
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (T.V.A.H.); (E.C.); (C.N.)
| | - Cédric Neveu
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (T.V.A.H.); (E.C.); (C.N.)
| | - Claude L. Charvet
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (T.V.A.H.); (E.C.); (C.N.)
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Izquierdo PG, Calahorro F, Thisainathan T, Atkins JH, Haszczyn J, Lewis CJ, Tattersall JEH, Green AC, Holden-Dye L, O'Connor V. Cholinergic signaling at the body wall neuromuscular junction distally inhibits feeding behavior in Caenorhabditis elegans. J Biol Chem 2021; 298:101466. [PMID: 34864060 PMCID: PMC8801469 DOI: 10.1016/j.jbc.2021.101466] [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: 02/12/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 12/27/2022] Open
Abstract
Complex biological functions within organisms are frequently orchestrated by systemic communication between tissues. In the model organism Caenorhabditis elegans, the pharyngeal and body wall neuromuscular junctions are two discrete structures that control feeding and locomotion, respectively. Separate, the well-defined neuromuscular circuits control these distinct tissues. Nonetheless, the emergent behaviors, feeding and locomotion, are coordinated to guarantee the efficiency of food intake. Here, we show that pharmacological hyperactivation of cholinergic transmission at the body wall muscle reduces the rate of pumping behavior. This was evidenced by a systematic screening of the effect of the cholinesterase inhibitor aldicarb on the rate of pharyngeal pumping on food in mutant worms. The screening revealed that the key determinants of the inhibitory effect of aldicarb on pharyngeal pumping are located at the body wall neuromuscular junction. In fact, the selective stimulation of the body wall muscle receptors with the agonist levamisole inhibited pumping in a lev-1-dependent fashion. Interestingly, this response was independent of unc-38, an alpha subunit of the nicotinic receptor classically expressed with lev-1 at the body wall muscle. This implies an uncharacterized lev-1-containing receptor underpins this effect. Overall, our results reveal that body wall cholinergic transmission not only controls locomotion but simultaneously inhibits feeding behavior.
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Affiliation(s)
- Patricia G Izquierdo
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Fernando Calahorro
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Thibana Thisainathan
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - James H Atkins
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Johanna Haszczyn
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Christian J Lewis
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
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Lautens MJ, Tan JH, Serrat X, Del Borrello S, Schertzberg MR, Fraser AG. Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics. PLoS Negl Trop Dis 2021; 15:e0009991. [PMID: 34843467 PMCID: PMC8659336 DOI: 10.1371/journal.pntd.0009991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/09/2021] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Soil transmitted helminths (STHs) are major human pathogens that infect over a billion people. Resistance to current anthelmintics is rising and new drugs are needed. Here we combine multiple approaches to find druggable targets in the anaerobic metabolic pathways STHs need to survive in their mammalian host. These require rhodoquinone (RQ), an electron carrier used by STHs and not their hosts. We identified 25 genes predicted to act in RQ-dependent metabolism including sensing hypoxia and RQ synthesis and found 9 are required. Since all 9 have mammalian orthologues, we used comparative genomics and structural modeling to identify those with active sites that differ between host and parasite. Together, we found 4 genes that are required for RQ-dependent metabolism and have different active sites. Finding these high confidence targets can open up in silico screens to identify species selective inhibitors of these enzymes as new anthelmintics.
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Affiliation(s)
- Margot J. Lautens
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - June H. Tan
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Xènia Serrat
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Andrew G. Fraser
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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25
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Ihara M. Ligand-gated ion channels as targets of neuroactive insecticides. Biosci Biotechnol Biochem 2021; 86:157-164. [PMID: 34849545 DOI: 10.1093/bbb/zbab202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/16/2021] [Indexed: 11/14/2022]
Abstract
The Cys-loop superfamily of ligand-gated ion channels (Cys-loop receptors) is one of the most ubiquitous ion channel families in vertebrates and invertebrates. Despite their ubiquity, they are targeted by several classes of pesticides, including neonicotinoids, phenylpyrazols, and macrolides such as ivermectins. The current commercialized compounds have high target site selectivity, which contributes to the safety of insecticide use. Structural analyses have accelerated progress in this field; notably, the X-ray crystal structures of acetylcholine binding protein and glutamate-gated Cl channels revealed the details of the molecular interactions between insecticides and their targets. Recently, the functional expression of the insect nicotinic acetylcholine receptor (nAChR) has been described, and detailed evaluations using the insect nAChR have emerged. This review discusses the basic concepts and the current insights into the molecular mechanisms of neuroactive insecticides targeting the ligand-gated ion channels, particularly Cys-loop receptors, and presents insights into target-based selectivity, resistance, and future drug design.
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26
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Lamassiaude N, Courtot E, Corset A, Charvet CL, Neveu C. Pharmacological characterization of novel heteromeric GluCl subtypes from C. elegans and parasitic nematodes. Br J Pharmacol 2021; 179:1264-1279. [PMID: 34623639 PMCID: PMC9306661 DOI: 10.1111/bph.15703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Macrocyclic lactones (MLs) are the most widely used broad-spectrum anthelmintic drugs for the treatment of parasitic nematodes impacting both human and animal health. MLs are known to act as agonist of the nematode glutamate-gated chloride channels (GluCls). However, for many important nematode species, the GluCls subunit composition and pharmacological properties remain largely unknown. In order to get new insights about the GluCl diversity and MLs mode of action, we identified and pharmacologically characterized receptors made of highly conserved GluCl subunits from the model nematode Caenorhabditis elegans, the human filarial nematode Brugia malayi and the horse parasite Parascaris univalens. EXPERIMENTAL APPROACH AVR-14, GLC-2, GLC3 and GLC-4 are the most conserved GluCl subunits throughout the Nematoda phylum. For each nematode species, we investigated the ability of these subunits to form either homomeric or heteromeric GluCls when expressed in Xenopus laevis oocytes and performed the detailed pharmacological characterization of the functional channels. KEY RESULTS Here, a total of 14 GluCls have been functionally reconstituted and heteromers formation was inferred from pharmacological criteria. Importantly, we report that the GLC-2 subunit plays a pivotal role in the composition of heteromeric GluCls in nematodes. In addition, we describe a novel GluCl subtype, made of the GLC-2/GLC-3 subunit combination, for which a high concentration of the anthelmintics ivermectin and moxidectin reversibly potentiate glutamate-induced response. CONCLUSION AND IMPLICATIONS This study brings new insights into the diversity of GluCl subtypes in nematodes and promote novel drug targets for the development of next generation anthelmintic compounds.
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Affiliation(s)
| | | | | | | | - Cédric Neveu
- INRAE, Université de Tours, ISP, Nouzilly, France
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27
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Functional Characterization of the Oxantel-Sensitive Acetylcholine Receptor from Trichuris muris. Pharmaceuticals (Basel) 2021; 14:ph14070698. [PMID: 34358124 PMCID: PMC8308736 DOI: 10.3390/ph14070698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/10/2021] [Accepted: 07/16/2021] [Indexed: 12/05/2022] Open
Abstract
The human whipworm, Trichuris trichiura, is estimated to infect 289.6 million people globally. Control of human trichuriasis is a particular challenge, as most anthelmintics have a limited single-dose efficacy, with the striking exception of the narrow-spectrum anthelmintic, oxantel. We recently identified a novel ACR-16-like subunit from the pig whipworm, T. suis which gave rise to a functional acetylcholine receptor (nAChR) preferentially activated by oxantel. However, there is no ion channel described in the mouse model parasite T. muris so far. Here, we have identified the ACR-16-like and ACR-19 subunits from T. muris, and performed the functional characterization of the receptors in Xenopus laevis oocytes using two-electrode voltage-clamp electrophysiology. We found that the ACR-16-like subunit from T. muris formed a homomeric receptor gated by acetylcholine whereas the ACR-19 failed to create a functional channel. The subsequent pharmacological analysis of the Tmu-ACR-16-like receptor revealed that acetylcholine and oxantel were equally potent. The Tmu-ACR-16-like was more responsive to the toxic agonist epibatidine, but insensitive to pyrantel, in contrast to the Tsu-ACR-16-like receptor. These findings confirm that the ACR-16-like nAChR from Trichuris spp. is a preferential drug target for oxantel, and highlights the pharmacological difference between Trichuris species.
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28
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Smelt CLC, Sanders VR, Puinean AM, Lansdell SJ, Goodchild J, Millar NS. Agonist and antagonist properties of an insect GABA-gated chloride channel (RDL) are influenced by heterologous expression conditions. PLoS One 2021; 16:e0254251. [PMID: 34234379 PMCID: PMC8263253 DOI: 10.1371/journal.pone.0254251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/24/2021] [Indexed: 11/18/2022] Open
Abstract
Pentameric ligand-gated ion channels (pLGICs) activated by the inhibitory neurotransmitter γ-aminobutyric acid (GABA) are expressed widely in both vertebrate and invertebrate species. One of the best characterised insect GABA-gated chloride channels is RDL, an abbreviation of ‘resistance to dieldrin’, that was originally identified by genetic screening in Drosophila melanogaster. Here we have cloned the analogous gene from the bumblebee Bombus terrestris audax (BtRDL) and examined its pharmacological properties by functional expression in Xenopus oocytes. Somewhat unexpectedly, the sensitivity of BtRDL to GABA, as measured by its apparent affinity (EC50), was influenced by heterologous expression conditions. This phenomenon was observed in response to alterations in the amount of cRNA injected; the length of time that oocytes were incubated before functional analysis; and by the presence or absence of a 3’ untranslated region. In contrast, similar changes in expression conditions were not associated with changes in apparent affinity with RDL cloned from D. melanogaster (DmRDL). Changes in apparent affinity with BtRDL were also observed following co-expression of a chaperone protein (NACHO). Similar changes in apparent affinity were observed with an allosteric agonist (propofol) and a non-competitive antagonist (picrotoxinin), indicating that expression-depended changes are not restricted to the orthosteric agonist binding site. Interestingly, instances of expression-dependent changes in apparent affinity have been reported previously for vertebrate glycine receptors, which are also members of the pLGIC super-family. Our observations with BtRDL are consistent with previous data obtained with vertebrate glycine receptors and indicates that agonist and antagonist apparent affinity can be influenced by the level of functional expression in a variety of pLGICs.
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Affiliation(s)
- Charles L C Smelt
- Division of Biosciences, University College London, London, United Kingdom
| | - Victoria R Sanders
- Division of Biosciences, University College London, London, United Kingdom
| | - Alin M Puinean
- Division of Biosciences, University College London, London, United Kingdom
| | - Stuart J Lansdell
- Division of Biosciences, University College London, London, United Kingdom
| | - Jim Goodchild
- Syngenta, Jealotts Hill International Research Centre, Bracknell, Berkshire, United Kingdom
| | - Neil S Millar
- Division of Biosciences, University College London, London, United Kingdom
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29
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Terpinskaya TI, Osipov AV, Kryukova EV, Kudryavtsev DS, Kopylova NV, Yanchanka TL, Palukoshka AF, Gondarenko EA, Zhmak MN, Tsetlin VI, Utkin YN. α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells. Mar Drugs 2021; 19:md19020118. [PMID: 33669933 PMCID: PMC7956437 DOI: 10.3390/md19020118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/01/2021] [Accepted: 02/18/2021] [Indexed: 12/11/2022] Open
Abstract
Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation.
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Affiliation(s)
- Tatiana I. Terpinskaya
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Alexey V. Osipov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Elena V. Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Denis S. Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Nina V. Kopylova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Tatsiana L. Yanchanka
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Alena F. Palukoshka
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Elena A. Gondarenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Maxim N. Zhmak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Victor I. Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
- Correspondence: or ; Tel.: +7-495-3366522
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Wit J, Dilks CM, Andersen EC. Complementary Approaches with Free-living and Parasitic Nematodes to Understanding Anthelmintic Resistance. Trends Parasitol 2020; 37:240-250. [PMID: 33317926 DOI: 10.1016/j.pt.2020.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022]
Abstract
Anthelmintic drugs are the major line of defense against parasitic nematode infections, but the arsenal is limited and resistance threatens sustained efficacy of the available drugs. Discoveries of the modes of action of these drugs and mechanisms of resistance have predominantly come from studies of a related nonparasitic nematode species, Caenorhabditis elegans, and the parasitic nematode Haemonchus contortus. Here, we discuss how our understanding of anthelmintic resistance and modes of action came from the interplay of results from each of these species. We argue that this 'cycle of discovery', where results from one species inform the design of experiments in the other, can use the complementary strengths of both to understand anthelmintic modes of action and mechanisms of resistance.
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Affiliation(s)
- Janneke Wit
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Clayton M Dilks
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL 60208, USA
| | - Erik C Andersen
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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31
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Kaji MD, Geary TG, Beech RN. A Functional Comparison of Homopentameric Nicotinic Acetylcholine Receptors (ACR-16) Receptors From Necator americanus and Ancylostoma ceylanicum. Front Mol Neurosci 2020; 13:601102. [PMID: 33324163 PMCID: PMC7725692 DOI: 10.3389/fnmol.2020.601102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/04/2020] [Indexed: 12/24/2022] Open
Abstract
Effective control of hookworm infections in humans and animals relies on using a small group of anthelmintics. Many of these drugs target cholinergic ligand-gated ion channels, yet the direct activity of anthelmintics has only been studied in a subset of these receptors, primarily in the non-parasitic nematode, Caenorhabditis elegans. Here we report the characterization of a homopentameric ionotropic acetylcholine receptor (AChR), ACR-16, from Necator americanus and Ancylostoma ceylanicum, the first known characterization of human hookworm ion channels. We used two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes to determine the pharmacodynamics of cholinergics and anthelmintics on ACR-16 from both species of hookworm. The A. ceylanicum receptor (Ace-ACR-16) was more sensitive to acetylcholine (EC50 = 20.64 ± 0.32 μM) and nicotine (EC50 = 24.37 ± 2.89 μM) than the N. americanus receptor (Nam-ACR-16) (acetylcholine EC50 = 170.1 ± 19.23 μM; nicotine EC50 = 597.9 ± 59.12 μM), at which nicotine was a weak partial agonist (% maximal acetylcholine response = 30.4 ± 7.4%). Both receptors were inhibited by 500 μM levamisole (Ace-ACR-16 = 65.1 ± 14.3% inhibition, Nam-ACR-16 = 79.5 ± 7.7% inhibition), and responded to pyrantel, but only Ace-ACR-16 responded to oxantel. We used in silico homology modeling to investigate potential structural differences that account for the differences in agonist binding and identified a loop E isoleucine 130 of Nam-ACR-16 as possibly playing a role in oxantel insensitivity. These data indicate that key functional differences exist among ACR-16 receptors from closely related species and suggest mechanisms for differential drug sensitivity.
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Affiliation(s)
- Mark D. Kaji
- Institute of Parasitology, McGill University, Montreal, QC, Canada
| | - Timothy G. Geary
- Institute of Parasitology, McGill University, Montreal, QC, Canada
- School of Biological Sciences, Queen’s University-Belfast, Belfast, United Kingdom
| | - Robin N. Beech
- Institute of Parasitology, McGill University, Montreal, QC, Canada
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32
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VAN Krugten J, Taris KKH, Peterman EJG. Imaging adult C. elegans live using light-sheet microscopy. J Microsc 2020; 281:214-223. [PMID: 32949409 PMCID: PMC7891351 DOI: 10.1111/jmi.12964] [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: 05/13/2020] [Revised: 08/19/2020] [Accepted: 09/17/2020] [Indexed: 12/01/2022]
Abstract
Live observation of biological phenomena in the context of living organisms can provide important insights in the mechanisms of these phenomena. However, the spatially complex and dynamic physiology of multicellular organisms can be a challenging environment to make observations with fluorescence microscopy. Due to the illumination of out‐of‐focus planes, confocal and particularly widefield fluorescence microscopy suffer from low signal‐to‐background ratio (SBR), photo toxicity and bleaching of fluorescent probes. In light‐sheet microscopy (LSM), solely the focal plane of the detection objective is illuminated, minimising out‐of‐focus fluorescence and photobleaching, thereby enhancing SBR, allowing for low laser intensities and longer acquisition periods. Here we present a straightforward light‐sheet microscope with a 1.0‐NA detection objective and a fast sample‐positioning stage that allows for four degrees of freedom. By imaging the sensory cilia and nervous system of living young adult C. elegans, we demonstrate that the instrument is well suited for relatively fast, volumetric imaging of larger (hundreds of micrometres cubed) living samples. These experiments demonstrate that such an instrument provides a valuable addition to commonly used widefield and confocal fluorescence microscopes. Lay description In fluorescence microscopy, sharp images can only be obtained when the light obtained from the section of the image that is in focus is not overwhelmed by light emerging from elsewhere. In this paper, we present a light‐sheet fluorescence microscope, based on the OpenSPIM initiative, with a magnification of 90× and a sensitive sample positioning stage that allows for fast controlled linear movement and rotation. In a light‐sheet microscope (LSM), the sample is illuminated from the side, compared to the direction of detection, limiting illumination only to the part of the sample that is imaged in the focal plane (general resources: Wikipedia or MicroscopyU). This does not only limit background noise, but also reduces damage to the sample due to phototoxicity. This makes a LSM particularly suitable for imaging living samples at high resolution, in three dimensions, over long periods of time. Our instrument was specifically designed for imaging adult C. elegans nematodes. We show here how the instrument compares to a standard epifluorescence microscope, imaging neuronal structures in the animals. The instrument proved well suited for fast volumetric imaging of larger cellular structures such as C. elegans neuronal cell bodies. Our experiments show that the instrument provides a valuable addition to widefield and confocal fluorescence microscopes commonly used to image adult C. elegans.
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Affiliation(s)
- J VAN Krugten
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - K-K H Taris
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Hahnel SR, Dilks CM, Heisler I, Andersen EC, Kulke D. Caenorhabditis elegans in anthelmintic research - Old model, new perspectives. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:237-248. [PMID: 33249235 PMCID: PMC7704361 DOI: 10.1016/j.ijpddr.2020.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 12/13/2022]
Abstract
For more than four decades, the free-living nematode Caenorhabditis elegans has been extensively used in anthelmintic research. Classic genetic screens and heterologous expression in the C. elegans model enormously contributed to the identification and characterization of molecular targets of all major anthelmintic drug classes. Although these findings provided substantial insights into common anthelmintic mechanisms, a breakthrough in the treatment and control of parasitic nematodes is still not in sight. Instead, we are facing increasing evidence that the enormous diversity within the phylum Nematoda cannot be recapitulated by any single free-living or parasitic species and the development of novel broad-spectrum anthelmintics is not be a simple goal. In the present review, we summarize certain milestones and challenges of the C. elegans model with focus on drug target identification, anthelmintic drug discovery and identification of resistance mechanisms. Furthermore, we present new perspectives and strategies on how current progress in C. elegans research will support future anthelmintic research.
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Affiliation(s)
| | - Clayton M Dilks
- Northwestern University, Department of Molecular Biosciences, Evanston, IL, USA.
| | | | - Erik C Andersen
- Northwestern University, Department of Molecular Biosciences, Evanston, IL, USA.
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Treinin M, Jin Y. Cholinergic transmission in C. elegans: Functions, diversity, and maturation of ACh-activated ion channels. J Neurochem 2020; 158:1274-1291. [PMID: 32869293 DOI: 10.1111/jnc.15164] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023]
Abstract
Acetylcholine is an abundant neurotransmitter in all animals. Effects of acetylcholine are excitatory, inhibitory, or modulatory depending on the receptor and cell type. Research using the nematode C. elegans has made ground-breaking contributions to the mechanistic understanding of cholinergic transmission. Powerful genetic screens for behavioral mutants or for responses to pharmacological reagents identified the core cellular machinery for synaptic transmission. Pharmacological reagents that perturb acetylcholine-mediated processes led to the discovery and also uncovered the composition and regulators of acetylcholine-activated channels and receptors. From a combination of electrophysiological and molecular cellular studies, we have gained a profound understanding of cholinergic signaling at the levels of synapses, neural circuits, and animal behaviors. This review will begin with a historical overview, then cover in-depth current knowledge on acetylcholine-activated ionotropic receptors, mechanisms regulating their functional expression and their functions in regulating locomotion.
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Affiliation(s)
- Millet Treinin
- Department of Medical Neurobiology, Hadassah Medical school - Hebrew University, Jerusalem, Israel
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
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Rufener L, Kaur K, Sarr A, Aaen SM, Horsberg TE. Nicotinic acetylcholine receptors: Ex-vivo expression of functional, non-hybrid, heteropentameric receptors from a marine arthropod, Lepeophtheirus salmonis. PLoS Pathog 2020; 16:e1008715. [PMID: 32716968 PMCID: PMC7419010 DOI: 10.1371/journal.ppat.1008715] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 08/11/2020] [Accepted: 06/18/2020] [Indexed: 11/18/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels mostly located in the post-synaptic membrane of cholinergic synapses. The natural neurotransmitter is acetylcholine, but they are also the direct targets for neonicotinoids, chemicals widely used against ectoparasites, arthropod vectors and agricultural pests. There are significant concerns regarding adverse effects of neonicotinoids on beneficial insects. In arthropods, functional nAChRs made of α subunits have been expressed from Drosophila genes, and hybrid receptors (sometimes also referred to as chimeric receptors) using species-specific α subunits and vertebrate β subunits have been expressed ex-vivo. Arthropod-specific nAChRs made of both α and β subunits from the target species have not been expressed ex-vivo. The aim of the current study was to express such receptors in Xenopus oocytes using only genes from Lepeophtheirus salmonis, to characterize them and study their modulation. Genes encoding α and β subunits of the nAChRs and three ancillary proteins, RIC-3, UNC-50 and UNC-74 were identified in the L. salmonis genome, subjected to RACE-PCR, cloned into an expression vector and the cRNA produced was then injected into Xenopus laevis oocytes. Co-expression of the ancillary proteins was essential for the successful expression of the L. salmonis nAChRs with both α and β subunits. Two functional nAChRs were identified: Lsa-nAChR1 consisting of α1, α2, β1 and β2 subunits, reconstituted to one distinct receptor, while Lsa-nAChR2, consisting of α3, β1 and β2 subunits reconstitutes receptors with two distinct characteristics. Out of seven neonicotinoids tested, six worked as partial agonist of Lsa-nAChR1 while only three did so for Lsa-nAChR2. Four non-neonicotinoid compounds tested had no effect on either of the nAChRs. The study demonstrated that fully functional, non-hybrid nAChRs containing both α and β subunits from an arthropod can be reconstituted ex-vivo by co-expression of essential ancillary proteins. Such models would be valuable for in-depth studies of effects by neonicotinoids and other compounds on target pests, as well as for studies of adverse effects on non-target arthropods. Nicotinic acetylcholine receptors, nAChRs, respond to the neurotransmitter acetylcholine or drugs like nicotine. These receptors are targets for neonicotinoids, the most commonly used compounds against ectoparasites and agricultural pests. In-depth studies of the function of these channels in arthropods are sparse, as no groups managed to reconstitute functional nAChRs made of both α and β subunits using genes only from the target arthropod in an ex-vivo system. We report the successful assembly of non-hybrid, fully functional nAChRs containing both α and β subunits from a marine arthropod, assembled and expressed in Xenopus laevis oocytes. We identified two possible combinations of α and β subunits producing functional receptors. We found ancillary proteins to be essential for successful expression and assembly of both α and β subunits into a functional receptor. The findings of the present study provide a basis for studying native nAChRs from arthropods, with a switch from hybrid nAChRs to species-specific native nAChRs.
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Affiliation(s)
- Lucien Rufener
- INVENesis Sarl, chemin de Belleroche, Neuchâtel, Switzerland
| | - Kiranpreet Kaur
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
- Aker BioMarine AS, Lysaker, Norway
| | - Anouk Sarr
- INVENesis Sarl, chemin de Belleroche, Neuchâtel, Switzerland
| | - Stian Mørch Aaen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
- Aqua Pharma Group, Hovemoveien, Lillehammer, Norway
| | - Tor Einar Horsberg
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
- * E-mail:
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Cofactor-enabled functional expression of fruit fly, honeybee, and bumblebee nicotinic receptors reveals picomolar neonicotinoid actions. Proc Natl Acad Sci U S A 2020; 117:16283-16291. [PMID: 32611810 PMCID: PMC7368294 DOI: 10.1073/pnas.2003667117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neonicotinoids acting on insect nicotinic acetylcholine receptors (nAChRs) are deployed for crop protection, but growing evidence for adverse effects on insect pollinators has led to restricted use of some neonicotinoids in the EU. It is therefore vital to understand the target site actions of neonicotinoids in pollinators, but to date the difficulties of heterologous expression of insect nAChRs have hampered progress. We have found that a thioredoxin (TMX3) enables robust functional expression of honeybee, bumblebee, and fruit fly nAChRs in Xenopus laevis oocytes. With this advance, we show that expressed bee nAChRs are more neonicotinoid-sensitive than those of fruit fly, and clothianidin can modulate both honeybee and bumblebee nAChRs at a concentration below that commonly observed in agricultural fields. The difficulty of achieving robust functional expression of insect nicotinic acetylcholine receptors (nAChRs) has hampered our understanding of these important molecular targets of globally deployed neonicotinoid insecticides at a time when concerns have grown regarding the toxicity of this chemotype to insect pollinators. We show that thioredoxin-related transmembrane protein 3 (TMX3) is essential to enable robust expression in Xenopus laevis oocytes of honeybee (Apis mellifera) and bumblebee (Bombus terrestris) as well as fruit fly (Drosophila melanogaster) nAChR heteromers targeted by neonicotinoids and not hitherto robustly expressed. This has enabled the characterization of picomolar target site actions of neonicotinoids, findings important in understanding their toxicity.
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Tikiyani V, Babu K. Claudins in the brain: Unconventional functions in neurons. Traffic 2020; 20:807-814. [PMID: 31418988 DOI: 10.1111/tra.12685] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022]
Abstract
Bonafide claudin proteins are functional and structural components of tight junctions and are largely responsible for barrier formation across epithelial and endothelial membranes. However, current advances in the understanding of claudin biology have revealed their unexpected functions in the brain. Apart from maintaining blood-brain barriers in the brain, other functions of claudins in neurons and at synapses have been largely elusive and are just coming to light. In this review, we summarize the functions of claudins in the brain and their association in neuronal diseases. Further, we go on to cover some recent studies that show that claudins play signaling functions in neurons by regulating trafficking of postsynaptic receptors and controlling dendritic morphogenesis in the model organism Caenorhabditis elegans.
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Affiliation(s)
- Vina Tikiyani
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India
| | - Kavita Babu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.,Centre for Neuroscience (CNS), Indian Institute of Science (IISc), Bangalore, India
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Pandey T, Smita SS, Mishra A, Sammi SR, Pandey R. Swertiamarin, a secoiridoid glycoside modulates nAChR and AChE activity. Exp Gerontol 2020; 138:111010. [PMID: 32590127 DOI: 10.1016/j.exger.2020.111010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 06/06/2020] [Accepted: 06/17/2020] [Indexed: 02/06/2023]
Abstract
The ailments related to a malfunction in cholinergic functioning currently employ the use of inhibitors for acetylcholinesterase (AChE) and N-methyl-d-aspartate (NMDA) receptors. The present study was designed to elucidate the potential of swertiamarin (SW), a secoiridoidal glycoside isolated from Enicostemma littorale in curtailing the cholinergic dysfunction. Using Caenorhabditis elegans as a model, SW was found to enhance neurotransmission by modulating AChE and nicotinic acetylcholine receptor (nAChR) activity; being orchestrated through up-regulation of unc-17 and unc-50. SW exhibited AChE inhibition both in vivo and cell-free system. The in silico molecular docking of SW and human AChE (hAChE) displayed good binding energy of -6.02. Interestingly, the increase in aldicarb and levamisole sensitivity post SW treatment was curtailed to a significant level in daf-16 and skn-1 mutants. SW raised the level of the endogenous antioxidant enzymes through up-regulation of sod-3 and gst-4 that act downstream to DAF-16 and SKN-1, imparting protection against neurodegeneration. The outcome of our study displays SW as a potential natural molecule for the amelioration of cholinergic dysfunction. Moreover, the study also indicates that SW elicits antioxidant response via up-modulation of daf-16 possibly through unc-17 upregulation. Further research on SW pertaining to the underlying mechanism and potential is expected to significantly advance the current understanding and design of possible ameliorative or near ameliorative regimens for cholinergic dysfunction.
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Affiliation(s)
- Taruna Pandey
- Aging Biology Lab, Microbial Technology and Nematology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India
| | - Shachi Shuchi Smita
- Aging Biology Lab, Microbial Technology and Nematology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India
| | - Anjali Mishra
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Shreesh Raj Sammi
- Aging Biology Lab, Microbial Technology and Nematology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India
| | - Rakesh Pandey
- Aging Biology Lab, Microbial Technology and Nematology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India.
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Patel RN, Richards DP, Duce IR, Birkett MA, Sattelle DB, Mellor IR. Actions on mammalian and insect nicotinic acetylcholine receptors of harmonine-containing alkaloid extracts from the harlequin ladybird Harmonia axyridis. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 166:104561. [PMID: 32448416 DOI: 10.1016/j.pestbp.2020.104561] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/11/2020] [Accepted: 03/01/2020] [Indexed: 06/11/2023]
Abstract
The harlequin ladybird, Harmonia axyridis (H. axyridis), possesses a strong chemical defence that has contributed to its invasive success. Ladybird beetle defensive chemicals, secreted in response to stress and also found on the coating of laid eggs, are rich in alkaloids that are thought to be responsible for this beetle's toxicity to other species. Recent studies have shown that alkaloids from several species of ladybird beetle can target nicotinic acetylcholine receptors (nAChRs) acting as receptor antagonists, hence we have explored the actions of alkaloids of the ladybird H. axyridis on both mammalian and insect nAChRs. Electrophysiological studies on native and functionally expressed recombinant nAChRs were used to establish whether an alkaloid extract from H. axyridis (HAE) targeted nAChRs and whether any selectivity exists for insect over mammalian receptors of this type. HAE was found to be an inhibitor of all nAChRs tested with the voltage-dependence of inhibition and the effect on ACh EC50 differing between nAChR subtypes. Our finding that an HAE fraction consisting almost entirely of harmonine had a strong inhibitory effect points to this alkaloid as a key component of nAChR inhibitory actions. Comparison of HAE inhibition between the mammalian and insect nAChRs investigated indicates some preference for the insect nAChR supporting the view that investigation of ladybird alkaloids shows promise as a method for identifying natural product leads for future insecticide development.
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Affiliation(s)
- Rohit N Patel
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - David P Richards
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Ian R Duce
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Michael A Birkett
- Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - David B Sattelle
- Centre for Respiratory Biology, UCL Respiratory, University College London, Rayne Building, University Street, London WC1E 6JF, UK.
| | - Ian R Mellor
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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Choudhary S, Buxton SK, Puttachary S, Verma S, Mair GR, McCoy CJ, Reaves BJ, Wolstenholme AJ, Martin RJ, Robertson AP. EAT-18 is an essential auxiliary protein interacting with the non-alpha nAChR subunit EAT-2 to form a functional receptor. PLoS Pathog 2020; 16:e1008396. [PMID: 32243475 PMCID: PMC7173930 DOI: 10.1371/journal.ppat.1008396] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 04/21/2020] [Accepted: 02/11/2020] [Indexed: 11/19/2022] Open
Abstract
Nematode parasites infect approximately 1.5 billion people globally and are a significant public health concern. There is an accepted need for new, more effective anthelmintic drugs. Nicotinic acetylcholine receptors on parasite nerve and somatic muscle are targets of the cholinomimetic anthelmintics, while glutamate-gated chloride channels in the pharynx of the nematode are affected by the avermectins. Here we describe a novel nicotinic acetylcholine receptor on the nematode pharynx that is a potential new drug target. This homomeric receptor is comprised of five non-α EAT-2 subunits and is not sensitive to existing cholinomimetic anthelmintics. We found that EAT-18, a novel auxiliary subunit protein, is essential for functional expression of the receptor. EAT-18 directly interacts with the mature receptor, and different homologs alter the pharmacological properties. Thus we have described not only a novel potential drug target but also a new type of obligate auxiliary protein for nAChRs. Soil-transmitted helminths affect about a quarter of the worlds’ population. Chemical anthelmintics not only alleviate the threat to human and animal health but also improve agricultural economics and food security. Here we have identified a “druggable” nicotinic acetylcholine receptor (nAChR) subunit, EAT-2, that constitutes the pharyngeal cholinergic receptor in nematodes. The receptor is required for feeding and possibly for reproductive behavior in worms. A selective therapeutic compound targeting this nAChR should either starve the worms or make them sluggish, helping with faster expulsion from the host. The EAT-2 pharyngeal nAChR is a unique receptor formed by five non-α subunits that lack vicinal cysteines in the ligand binding loop-C. To date, all cation selective nAChRs contain at least two α subunits. It is possible that EAT-2 subunits have retained functionality without the vicinal cysteines due to evolutionary modifications and expresses as a new nAChR subtype which doesn’t fit the established dogma based on the study of vertebrate receptors. Our findings also identified a new type of auxiliary protein subunit, which is essential for functional expression of the pharyngeal nAChR and also modulates its pharmacology. To the best of our knowledge, this is the first report of an auxiliary protein that is essential for functional expression in any cys-loop ligand-gated ion channel.
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Affiliation(s)
- Shivani Choudhary
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Samuel K. Buxton
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Saurabh Verma
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Gunnar R. Mair
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Ciaran J. McCoy
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Barbara J. Reaves
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Adrian J. Wolstenholme
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Richard J. Martin
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Alan P. Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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Co-occurring WARS2 and CHRNA6 mutations in a child with a severe form of infantile parkinsonism. Parkinsonism Relat Disord 2020; 72:75-79. [PMID: 32120303 DOI: 10.1016/j.parkreldis.2020.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the molecular cause(s) underlying a severe form of infantile-onset parkinsonism and characterize functionally the identified variants. METHODS A trio-based whole exome sequencing (WES) approach was used to identify the candidate variants underlying the disorder. In silico modeling, and in vitro and in vivo studies were performed to explore the impact of these variants on protein function and relevant cellular processes. RESULTS WES analysis identified biallelic variants in WARS2, encoding the mitochondrial tryptophanyl tRNA synthetase (mtTrpRS), a gene whose mutations have recently been associated with multiple neurological phenotypes, including childhood-onset, levodopa-responsive or unresponsive parkinsonism in a few patients. A substantial reduction of mtTrpRS levels in mitochondria and reduced OXPHOS function was demonstrated, supporting their pathogenicity. Based on the infantile-onset and severity of the phenotype, additional variants were considered as possible genetic modifiers. Functional assessment of a selected panel of candidates pointed to a de novo missense mutation in CHRNA6, encoding the α6 subunit of neuronal nicotinic receptors, which are involved in the cholinergic modulation of dopamine release in the striatum, as a second event likely contributing to the phenotype. In silico, in vitro (Xenopus oocytes and GH4C1 cells) and in vivo (C. elegans) analyses demonstrated the disruptive effects of the mutation on acetylcholine receptor structure and function. CONCLUSION Our findings consolidate the association between biallelic WARS2 mutations and movement disorders, and suggest CHRNA6 as a genetic modifier of the phenotype.
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Automated Platform for Long-Term Culture and High-Content Phenotyping of Single C. elegans Worms. Sci Rep 2019; 9:14340. [PMID: 31586133 PMCID: PMC6778082 DOI: 10.1038/s41598-019-50920-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/19/2019] [Indexed: 01/01/2023] Open
Abstract
The nematode Caenorhabditis elegans is a suitable model organism in drug screening. Traditionally worms are grown on agar plates, posing many challenges for long-term culture and phenotyping of animals under identical conditions. Microfluidics allows for 'personalized' phenotyping, as microfluidic chips permit collecting individual responses over worms' full life. Here, we present a multiplexed, high-throughput, high-resolution microfluidic approach to culture C. elegans from embryo to the adult stage at single animal resolution. We allocated single embryos to growth chambers, for observing the main embryonic and post-embryonic development stages and phenotypes, while exposing worms to up to 8 different well-controlled chemical conditions. Our approach allowed eliminating bacteria aggregation and biofilm formation-related clogging issues, which enabled us performing up to 80 hours of automated single worm culture studies. Our microfluidic platform is linked with an automated phenotyping code that registers organism-associated phenotypes at high-throughput. We validated our platform with a dose-response study of the anthelmintic drug tetramisole by studying its influence through the life cycle of the nematodes. In parallel, we could observe development effects and variations in single embryo and worm viability due to the bleaching procedure that is standardly used for harvesting the embryos from a worm culture agar plate.
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Choudhary S, Tipton JG, Abongwa M, Brewer MT, Chelladurai JJ, Musselman N, Martin RJ, Robertson AP. Pharmacological characterization of a homomeric nicotinic acetylcholine receptor formed by Ancylostoma caninum ACR-16. INVERTEBRATE NEUROSCIENCE : IN 2019; 19:11. [PMID: 31486912 PMCID: PMC7869652 DOI: 10.1007/s10158-019-0231-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/17/2019] [Indexed: 01/07/2023]
Abstract
Parasitic nematode infections are treated using anthelmintic drugs, some of which target nicotinic acetylcholine receptors (nAChRs) located in different parasite tissues. The limited arsenal of anthelmintic agents and the prevalence of drug resistance imply that future defense against parasitic infections will depend on the discovery of novel targets and therapeutics. Previous studies have suggested that Ascaris suum ACR-16 nAChRs are a suitable target for the development of antinematodal drugs. In this study, we characterized the pharmacology of the Ancylostoma caninum ACR-16 receptor using two-electrode voltage-clamp electrophysiology. This technique allowed us to study the effects of cholinergic agonists and antagonists on the nematode nAChRs expressed in Xenopus laevis oocytes. Aca-ACR-16 was not sensitive to many of the existing cholinomimetic anthelmintics (levamisole, oxantel, pyrantel, and tribendimidine). 3-Bromocytisine was the most potent agonist (> 130% of the control acetylcholine current) on the Aca-ACR-16 nAChR but, unlike Asu-ACR-16, oxantel did not activate the receptor. The mean time constants of desensitization for agonists on Aca-ACR-16 were longer than the rates observed in Asu-ACR-16. In contrast to Asu-ACR-16, the A. caninum receptor was completely inhibited by DHβE and moderately inhibited by α-BTX. In conclusion, we have successfully reconstituted a fully functional homomeric nAChR, ACR-16, from A. caninum, a model for human hookworm infections. The pharmacology of the receptor is distinct from levamisole-sensitive nematode receptors. The ACR-16 homologue also displayed some pharmacological differences from Asu-ACR-16. Hence, A. caninum ACR-16 may be a valid target site for the development of anthelmintics against hookworm infections.
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Affiliation(s)
- Shivani Choudhary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - James G Tipton
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Melanie Abongwa
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Matthew T Brewer
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Jeba Jesudoss Chelladurai
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Nicole Musselman
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA.
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Dubois O, Allanic C, Charvet CL, Guégnard F, Février H, Théry-Koné I, Cortet J, Koch C, Bouvier F, Fassier T, Marcon D, Magnin-Robert JB, Peineau N, Courtot E, Huau C, Meynadier A, Enguehard-Gueiffier C, Neveu C, Boudesocque-Delaye L, Sallé G. Lupin (Lupinus spp.) seeds exert anthelmintic activity associated with their alkaloid content. Sci Rep 2019; 9:9070. [PMID: 31227784 PMCID: PMC6588613 DOI: 10.1038/s41598-019-45654-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/12/2019] [Indexed: 12/20/2022] Open
Abstract
The growing range of drug resistant parasitic nematode populations threatens the sustainability of ruminant farming worldwide. In this context, nutraceuticals, animal feed that provides necessary dietary requirements while ensuring parasite control, could contribute to increase farming sustainability in developed and low resource settings. In this study, we evaluated the anthelmintic potential of lupin seed extracts against the major ruminant trichostrongylids, Haemonchus contortus and Teladorsagia circumcincta. In vitro observations showed that seed extracts from commercially available lupin varieties could significantly but moderately inhibit larval migration. This anthelmintic effect was mediated by the seed alkaloid content and was potent against both fully susceptible and multidrug resistant H. contortus isolates as well as a susceptible T. circumcincta isolate. Analytical chemistry revealed a set of four lupanine and sparteine-derivatives with anthelmintic activity, and electrophysiology assays on recombinant nematode acetylcholine receptors suggested an antagonistic mode of action for lupin alkaloids. An in vivo trial in H. contortus infected lupin-fed ewes and goats failed to demonstrate any direct anthelmintic effect of crude lupin seeds but infected lupin-fed goats suffered significantly less parasite-mediated blood losses. Altogether, our findings suggest that the anthelmintic potential of lupin remains limited. However, the potent alkaloids identified could lead to the development of novel drugs or may be used in combination with current anthelmintics to improve their efficacy.
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Affiliation(s)
- O Dubois
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France.,EA 7502 SIMBA, Université de Tours, Faculté de Pharmacie, F-37000, Tours, France
| | - C Allanic
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - C L Charvet
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - F Guégnard
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - H Février
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - I Théry-Koné
- EA 7502 SIMBA, Université de Tours, Faculté de Pharmacie, F-37000, Tours, France
| | - J Cortet
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - C Koch
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - F Bouvier
- UE332 La Sapinière, INRA, F-18174, Osmoy, France
| | - T Fassier
- UE332 La Sapinière, INRA, F-18174, Osmoy, France
| | - D Marcon
- UE332 La Sapinière, INRA, F-18174, Osmoy, France
| | - J B Magnin-Robert
- Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - N Peineau
- Département Physiologie Animale, Université de Tours, Faculté des Sciences et Techniques, F-37000, Tours, France
| | - E Courtot
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - C Huau
- GenPhySE, INRA, Université de Toulouse, INPT, ENVT, F-31326, Castanet-Tolosan, France
| | - A Meynadier
- GenPhySE, INRA, Université de Toulouse, INPT, ENVT, F-31326, Castanet-Tolosan, France
| | | | - C Neveu
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France
| | - L Boudesocque-Delaye
- EA 7502 SIMBA, Université de Tours, Faculté de Pharmacie, F-37000, Tours, France
| | - G Sallé
- UMR1282 Infectiologie et Santé Publique, INRA, Université de Tours, F-37380, Nouzilly, France.
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Ben Soussia I, El Mouridi S, Kang D, Leclercq-Blondel A, Khoubza L, Tardy P, Zariohi N, Gendrel M, Lesage F, Kim EJ, Bichet D, Andrini O, Boulin T. Mutation of a single residue promotes gating of vertebrate and invertebrate two-pore domain potassium channels. Nat Commun 2019; 10:787. [PMID: 30770809 PMCID: PMC6377628 DOI: 10.1038/s41467-019-08710-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/23/2019] [Indexed: 01/28/2023] Open
Abstract
Mutations that modulate the activity of ion channels are essential tools to understand the biophysical determinants that control their gating. Here, we reveal the conserved role played by a single amino acid position (TM2.6) located in the second transmembrane domain of two-pore domain potassium (K2P) channels. Mutations of TM2.6 to aspartate or asparagine increase channel activity for all vertebrate K2P channels. Using two-electrode voltage-clamp and single-channel recording techniques, we find that mutation of TM2.6 promotes channel gating via the selectivity filter gate and increases single channel open probability. Furthermore, channel gating can be progressively tuned by using different amino acid substitutions. Finally, we show that the role of TM2.6 was conserved during evolution by rationally designing gain-of-function mutations in four Caenorhabditis elegans K2P channels using CRISPR/Cas9 gene editing. This study thus describes a simple and powerful strategy to systematically manipulate the activity of an entire family of potassium channels. Mutations that modulate the activity of ion channels are essential tools to understand the biophysical determinants that control their gating. Here authors reveal the role played by a single residue in the second transmembrane domain of vertebrate and invertebrate two-pore domain potassium channels.
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Affiliation(s)
- Ismail Ben Soussia
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Sonia El Mouridi
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Dawon Kang
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, 52727, South Korea
| | - Alice Leclercq-Blondel
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Lamyaa Khoubza
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Philippe Tardy
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Nora Zariohi
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Marie Gendrel
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Florian Lesage
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Eun-Jin Kim
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, 52727, South Korea
| | - Delphine Bichet
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Olga Andrini
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France.
| | - Thomas Boulin
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France.
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46
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Blanco MG, Vela Gurovic MS, Silbestri GF, Garelli A, Giunti S, Rayes D, De Rosa MJ. Diisopropylphenyl-imidazole (DII): A new compound that exerts anthelmintic activity through novel molecular mechanisms. PLoS Negl Trop Dis 2018; 12:e0007021. [PMID: 30557347 PMCID: PMC6312359 DOI: 10.1371/journal.pntd.0007021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/31/2018] [Accepted: 11/26/2018] [Indexed: 11/26/2022] Open
Abstract
Nematode parasites cause substantial morbidity to billions of people and considerable losses in livestock and food crops. The repertoire of effective anthelmintic compounds for treating these parasitoses is very limited, as drug development has been delayed for decades. Moreover, resistance has become a global concern in livestock parasites and is an emerging issue for human helminthiasis. Therefore, anthelmintics with novel mechanisms of action are urgently needed. Taking advantage of Caenorhabditis elegans as an established model system, we here screened the nematicidal potential of novel imidazolium and imidazole derivatives. One of these derivatives, diisopropylphenyl-imidazole (DII), is lethal to C. elegans at both mature and immature stages. This lethal effect appears to be specific because DII concentrations which prove to be toxic to C. elegans do not induce significant lethality on bacteria, Drosophila melanogaster, and HEK-293 cells. Our analysis of DII action on C. elegans mutant strains determined that, in the adult stage, null mutants of unc-29 are resistant to the drug. Muscle expression of this gene completely restores DII sensitivity. UNC-29 has been largely reported as an essential constituent of the levamisole-sensitive muscle nicotinic receptor (L-AChR). Nevertheless, null mutants in unc-63 and lev-8 (essential and non-essential subunits of L-AChRs, respectively) are as sensitive to DII as the wild-type strain. Therefore, our results suggest that DII effects on adult nematodes rely on a previously unidentified UNC-29-containing muscle AChR, different from the classical L-AChR. Interestingly, DII targets appear to be different between larvae and adults, as unc-29 null mutant larvae are sensitive to the drug. The existence of more than one target could delay resistance development. Its lethality on C. elegans, its harmlessness in non-nematode species and its novel and dual mechanism of action make DII a promising candidate compound for anthelmintic therapy. Intestinal helminth infections affect approximately one-third of the world’s population, particularly in developing countries. Paradoxically, drug development in this area has been delayed for years. In addition, resistance to currently available drugs is also an emerging global concern. Therefore, there is an urgent need for new and effective anthelmintics. In this work, we used C. elegans as a model for parasitic nematodes to screen the anthelmintic activity of several imidazole-derivative compounds. We found a compound, diisopropylphenyl-imidazole (DII), that is lethal to both mature and immature stages of C. elegans. The DII nematicidal mechanism of action depends on a novel UNC-29-containing AChR in adult C. elegans muscle. Since this mechanism is different from those of currently used anthelmintics, it could constitute a therapeutic option when traditional anthelmintic agents fail. In addition, we found that the DII larvicidal effect depends on a different target to that of adult stages. The fact that DII produces lethality through different targets may delay resistance development. The specificity and novel mode of action of DII, which includes differential targeting in larvae and adult nematodes, support its potential as a promising drug candidate to treat helminthiasis.
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Affiliation(s)
- María Gabriela Blanco
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - María Soledad Vela Gurovic
- Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina.,CERZOS UNS-CONICET CCT, Bahía Blanca, Argentina
| | - Gustavo Fabián Silbestri
- Dpto de Química, Universidad Nacional del Sur (UNS)-CONICET, Instituto de Química del Sur (INQUISUR), Bahía Blanca, Argentina
| | - Andrés Garelli
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Sebastián Giunti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Diego Rayes
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - María José De Rosa
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
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47
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Charvet CL, Guégnard F, Courtot E, Cortet J, Neveu C. Nicotine-sensitive acetylcholine receptors are relevant pharmacological targets for the control of multidrug resistant parasitic nematodes. Int J Parasitol Drugs Drug Resist 2018; 8:540-549. [PMID: 30502120 PMCID: PMC6287576 DOI: 10.1016/j.ijpddr.2018.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 12/19/2022]
Abstract
The control of parasitic nematodes impacting animal health relies on the use of broad spectrum anthelmintics. However, intensive use of these drugs has led to the selection of resistant parasites in livestock industry. In that respect, there is currently an urgent need for novel compounds able to control resistant parasites. Nicotine has also historically been used as a de-wormer but was removed from the market when modern anthelmintics became available. The pharmacological target of nicotine has been identified in nematodes as acetylcholine-gated ion channels. Nicotinic-sensitive acetylcholine receptors (N-AChRs) therefore represent validated pharmacological targets that remain largely under-exploited. In the present study, using an automated larval migration assay (ALMA), we report that nicotinic derivatives efficiently paralyzed a multiple (benzimidazoles/levamisole/pyrantel/ivermectin) resistant field isolate of H. contortus. Using C. elegans as a model we confirmed that N-AChRs are preferential targets for nornicotine and anabasine. Functional expression of the homomeric N-AChR from C. elegans and the distantly related horse parasite Parascaris equorum in Xenopus oocytes highlighted some striking differences in their respective pharmacological properties towards nicotine derivative sensitivity. This work validates the exploitation of the nicotine receptors of parasitic nematodes as targets for the development of resistance-breaking compounds.
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Affiliation(s)
| | | | - Elise Courtot
- ISP, INRA, Université Tours, UMR1282, 37380, Nouzilly, France
| | - Jacques Cortet
- ISP, INRA, Université Tours, UMR1282, 37380, Nouzilly, France
| | - Cedric Neveu
- ISP, INRA, Université Tours, UMR1282, 37380, Nouzilly, France.
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48
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D'Alessandro M, Richard M, Stigloher C, Gache V, Boulin T, Richmond JE, Bessereau JL. CRELD1 is an evolutionarily-conserved maturational enhancer of ionotropic acetylcholine receptors. eLife 2018; 7:39649. [PMID: 30407909 PMCID: PMC6245729 DOI: 10.7554/elife.39649] [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: 07/12/2018] [Accepted: 11/05/2018] [Indexed: 12/22/2022] Open
Abstract
The assembly of neurotransmitter receptors in the endoplasmic reticulum limits the number of receptors delivered to the plasma membrane, ultimately controlling neurotransmitter sensitivity and synaptic transfer function. In a forward genetic screen conducted in the nematode C. elegans, we identified crld-1 as a gene required for the synaptic expression of ionotropic acetylcholine receptors (AChR). We demonstrated that the CRLD-1A isoform is a membrane-associated ER-resident protein disulfide isomerase (PDI). It physically interacts with AChRs and promotes the assembly of AChR subunits in the ER. Mutations of Creld1, the human ortholog of crld-1a, are responsible for developmental cardiac defects. We showed that Creld1 knockdown in mouse muscle cells decreased surface expression of AChRs and that expression of mouse Creld1 in C. elegans rescued crld-1a mutant phenotypes. Altogether these results identify a novel and evolutionarily-conserved maturational enhancer of AChR biogenesis, which controls the abundance of functional receptors at the cell surface.
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Affiliation(s)
- Manuela D'Alessandro
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Magali Richard
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Christian Stigloher
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Vincent Gache
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Thomas Boulin
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, United States
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
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49
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Turani O, Hernando G, Corradi J, Bouzat C. Activation of Caenorhabditis elegans Levamisole-Sensitive and Mammalian Nicotinic Receptors by the Antiparasitic Bephenium. Mol Pharmacol 2018; 94:1270-1279. [PMID: 30190363 DOI: 10.1124/mol.118.113357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/29/2018] [Indexed: 11/22/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels involved in neuromuscular transmission. In nematodes, muscle nAChRs are targets of antiparasitic drugs. Bephenium is an anthelmintic compound whose molecular action in the free-living nematode Caenorhabditis elegans, which is a model for anthelmintic drug discovery, is poorly known. We explored the effect of bephenium on C. elegans locomotion and applied single-channel recordings to identify its molecular target, mechanism of action, and selectivity between mammalian and C. elegans nAChRs. As in parasites, bephenium paralyzes C. elegans A mutant strain lacking the muscle levamisole-sensitive nAChR (L-AChR) shows full resistance to bephenium, indicating that this receptor is the target site. Bephenium activates L-AChR channels from larvae muscle cells in the micromolar range. Channel activity is similar to that elicited by levamisole, appearing mainly as isolated brief openings. Our analysis revealed that bephenium is an agonist of L-AChR and an open-channel blocker at higher concentrations. It also activates mammalian muscle nAChRs. Opening events are significantly briefer than those elicited by ACh and do not appear in activation episodes at a range of concentrations, indicating that it is a very weak agonist of mammalian nAChRs. Recordings in the presence of ACh showed that bephenium acts as a voltage-dependent channel blocker and a low-affinity agonist. Molecular docking into homology-modeled binding-site interfaces represent the binding mode of bephenium that explains its partial agonism. Given the great diversity of helminth nAChRs and the overlap of their pharmacological profiles, unraveling the basis of drug receptor-selectivity will be required for rational design of anthelmintic drugs.
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Affiliation(s)
- Ornella Turani
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Guillermina Hernando
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Jeremías Corradi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
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50
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Spensley M, Del Borrello S, Pajkic D, Fraser AG. Acute Effects of Drugs on Caenorhabditis elegans Movement Reveal Complex Responses and Plasticity. G3 (BETHESDA, MD.) 2018; 8:2941-2952. [PMID: 30061375 PMCID: PMC6118317 DOI: 10.1534/g3.118.200374] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/06/2018] [Indexed: 11/21/2022]
Abstract
Many drugs act very rapidly - they can turn on or off their targets within minutes in a whole animal. What are the acute effects of drug treatment and how does an animal respond to these? We developed a simple assay to measure the acute effects of drugs on C. elegans movement and examined the effects of a range of compounds including neuroactive drugs, toxins, environmental stresses and novel compounds on worm movement over a time period of 3 hr. We found a wide variety of acute responses. Many compounds cause rapid paralysis which may be permanent or followed by one or more recovery phases. The recoveries are not the result of some generic stress response but are specific to the drug e.g., recovery from paralysis due to a neuroactive drug requires neurotransmitter pathways whereas recovery from a metabolic inhibitor requires metabolic changes. Finally, we also find that acute responses can vary greatly across development and that there is extensive natural variation in acute responses. In summary, acute responses are sensitive probes of the ability of biological networks to respond to drug treatment and these responses can reveal the action of unexplored pathways.
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Affiliation(s)
- Mark Spensley
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
| | - Samantha Del Borrello
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
| | - Djina Pajkic
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
| | - Andrew G Fraser
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 3E1 Canada
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