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Taferner A, Pircher H, Koziel R, von Grafenstein S, Baraldo G, Palikaras K, Liedl KR, Tavernarakis N, Jansen-Dürr P. FAH domain containing protein 1 (FAHD-1) is required for mitochondrial function and locomotion activity in C. elegans. PLoS One 2015; 10:e0134161. [PMID: 26266933 PMCID: PMC4534308 DOI: 10.1371/journal.pone.0134161] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/06/2015] [Indexed: 12/31/2022] Open
Abstract
The fumarylacetoacetate hydrolase (FAH) protein superfamily of metabolic enzymes comprises a diverse set of enzymatic functions, including ß-diketone hydrolases, decarboxylases, and isomerases. Of note, the FAH superfamily includes many prokaryotic members with very distinct functions that lack homologs in eukaryotes. A prokaryotic member of the FAH superfamily, referred to as Cg1458, was shown to encode a soluble oxaloacetate decarboxylase (ODx). Based on sequence homologies to Cg1458, we recently identified human FAH domain containing protein-1 (FAHD1) as the first eukaryotic oxaloacetate decarboxylase. The physiological functions of ODx in eukaryotes remain unclear. Here we have probed the function of fahd-1, the nematode homolog of FAHD1, in the context of an intact organism. We found that mutation of fahd-1 resulted in reduced brood size, a deregulation of the egg laying process and a severe locomotion deficit, characterized by a reduced frequency of body bends, reduced exploratory movements and reduced performance in an endurance exercise test. Notably, mitochondrial function was altered in the fahd-1(tm5005) mutant strain, as shown by a reduction of mitochondrial membrane potential and a reduced oxygen consumption of fahd-1(tm5005) animals. Mitochondrial dysfunction was accompanied by lifespan extension in worms grown at elevated temperature; however, unlike in mutant worms with a defect in the electron transport chain, the mitochondrial unfolded protein response was not upregulated in worms upon inactivation of fahd-1. Together these data establish a role of fahd-1 to maintain mitochondrial function and consequently physical activity in nematodes.
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Affiliation(s)
- Andrea Taferner
- Institute for Biomedical Aging Research and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - Haymo Pircher
- Institute for Biomedical Aging Research and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - Rafal Koziel
- Institute for Biomedical Aging Research and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - Susanne von Grafenstein
- Institute for General, Inorganic and Theoretical Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Innrain 80–82, 6020, Innsbruck, Austria
| | - Giorgia Baraldo
- Institute for Biomedical Aging Research and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - Konstantinos Palikaras
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Klaus R. Liedl
- Institute for General, Inorganic and Theoretical Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Innrain 80–82, 6020, Innsbruck, Austria
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research and Center for Molecular Biosciences Innsbruck (CMBI), Universität Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
- * E-mail:
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Neuronal serotonin release triggers the heat shock response in C. elegans in the absence of temperature increase. Curr Biol 2014; 25:163-174. [PMID: 25557666 DOI: 10.1016/j.cub.2014.11.040] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/13/2014] [Accepted: 11/17/2014] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cellular mechanisms aimed at repairing protein damage and maintaining homeostasis, widely understood to be triggered by the damage itself, have recently been shown to be under cell nonautonomous control in the metazoan C. elegans. The heat shock response (HSR) is one such conserved mechanism, activated by cells upon exposure to proteotoxic conditions such as heat. Previously, we had shown that this conserved cytoprotective response is regulated by the thermosensory neuronal circuitry of C. elegans. Here, we investigate the mechanisms and physiological relevance of neuronal control. RESULTS By combining optogenetic methods with live visualization of the dynamics of the heat shock transcription factor (HSF1), we show that excitation of the AFD thermosensory neurons is sufficient to activate HSF1 in another cell, even in the absence of temperature increase. Excitation of the AFD thermosensory neurons enhances serotonin release. Serotonin release elicited by direct optogenetic stimulation of serotonergic neurons activates HSF1 and upregulates molecular chaperones through the metabotropic serotonin receptor SER-1. Consequently, excitation of serotonergic neurons alone can suppress protein misfolding in C. elegans peripheral tissue. CONCLUSIONS These studies imply that thermosensory activity coupled to serotonergic signaling is sufficient to activate the protective HSR prior to frank proteotoxic damage. The ability of neurosensory release of serotonin to control cellular stress responses and activate HSF1 has powerful implications for the treatment of protein conformation diseases.
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Yamane T. Genetic variation in the effect of monoamines on female mating receptivity and oviposition in the adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). BMC Evol Biol 2014; 14:172. [PMID: 25098756 PMCID: PMC4360256 DOI: 10.1186/s12862-014-0172-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/23/2014] [Indexed: 12/16/2022] Open
Abstract
Background Female mate choice after mating is a strong force in sexual selection and could lead to coevolution of mating traits between the sexes. How females of different genotypes respond to substances in the male ejaculate should be mediated by females’ mate choices. Monoamines regulate animal physiology and behavior, including the post-mating behavior of females of the adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). This study examined differences in females’ response to four monoamines (dopamine, octopamine, tyramine, serotonin) between strains from different populations of C. chinensis. Results Injection with either octopamine or tyramine, two kinds of monoamines significantly reduced female receptivity in two strains with low remating frequencies. None of the four monoamines reduced female receptivity in one strain with high remating frequencies. However, all monoamines reduced it in another strain with high remating frequencies. Oviposition was activated by tyramine on days 1–5 or by serotonin on days 4 and 5 in the two strains with low remating frequencies, but only on day 1 or day 4 in the strains with high remating frequencies. Conclusion These differences in female response to monoamines, especially tyramine and serotonin, correspond with results of previous studies. They indicate differences in female response to male substances that reduce receptivity and activate oviposition. These findings suggest relationships between the differences in female response to male substances among populations and mutations in the pathways of monoamine biosynthesis or transmission, which in turn determine female mate choice in response to male substances.
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Dwyer DS, Aamodt E, Cohen B, Buttner EA. Drug elucidation: invertebrate genetics sheds new light on the molecular targets of CNS drugs. Front Pharmacol 2014; 5:177. [PMID: 25120487 PMCID: PMC4112795 DOI: 10.3389/fphar.2014.00177] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/09/2014] [Indexed: 02/02/2023] Open
Abstract
Many important drugs approved to treat common human diseases were discovered by serendipity, without a firm understanding of their modes of action. As a result, the side effects and interactions of these medications are often unpredictable, and there is limited guidance for improving the design of next-generation drugs. Here, we review the innovative use of simple model organisms, especially Caenorhabditis elegans, to gain fresh insights into the complex biological effects of approved CNS medications. Whereas drug discovery involves the identification of new drug targets and lead compounds/biologics, and drug development spans preclinical testing to FDA approval, drug elucidation refers to the process of understanding the mechanisms of action of marketed drugs by studying their novel effects in model organisms. Drug elucidation studies have revealed new pathways affected by antipsychotic drugs, e.g., the insulin signaling pathway, a trace amine receptor and a nicotinic acetylcholine receptor. Similarly, novel targets of antidepressant drugs and lithium have been identified in C. elegans, including lipid-binding/transport proteins and the SGK-1 signaling pathway, respectively. Elucidation of the mode of action of anesthetic agents has shown that anesthesia can involve mitochondrial targets, leak currents, and gap junctions. The general approach reviewed in this article has advanced our knowledge about important drugs for CNS disorders and can guide future drug discovery efforts.
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Affiliation(s)
- Donard S. Dwyer
- Department of Psychiatry–Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center-ShreveportShreveport, LA, USA
| | - Eric Aamodt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-ShreveportShreveport, LA, USA
| | - Bruce Cohen
- Department of Psychiatry, Harvard Medical SchoolBoston, MA, USA
- Mailman Research Center, McLean HospitalBelmont, MA, USA
| | - Edgar A. Buttner
- Mailman Research Center, McLean HospitalBelmont, MA, USA
- Department of Neurology–Department of Psychiatry, McLean Hospital, Harvard Medical SchoolBelmont, MA, USA
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Cunningham KA, Bouagnon AD, Barros AG, Lin L, Malard L, Romano-Silva MA, Ashrafi K. Loss of a neural AMP-activated kinase mimics the effects of elevated serotonin on fat, movement, and hormonal secretions. PLoS Genet 2014; 10:e1004394. [PMID: 24921650 PMCID: PMC4055570 DOI: 10.1371/journal.pgen.1004394] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 04/07/2014] [Indexed: 12/30/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is an evolutionarily conserved master regulator of metabolism and a therapeutic target in type 2 diabetes. As an energy sensor, AMPK activity is responsive to both metabolic inputs, for instance the ratio of AMP to ATP, and numerous hormonal cues. As in mammals, each of two genes, aak-1 and aak-2, encode for the catalytic subunit of AMPK in C. elegans. Here we show that in C. elegans loss of aak-2 mimics the effects of elevated serotonin signaling on fat reduction, slowed movement, and promoting exit from dauer arrest. Reconstitution of aak-2 in only the nervous system restored wild type fat levels and movement rate to aak-2 mutants and reconstitution in only the ASI neurons was sufficient to significantly restore dauer maintenance to the mutant animals. As in elevated serotonin signaling, inactivation of AAK-2 in the ASI neurons caused enhanced secretion of dense core vesicles from these neurons. The ASI neurons are the site of production of the DAF-7 TGF-β ligand and the DAF-28 insulin, both of which are secreted by dense core vesicles and play critical roles in whether animals stay in dauer or undergo reproductive development. These findings show that elevated levels of serotonin promote enhanced secretions of systemic regulators of pro-growth and differentiation pathways through inactivation of AAK-2. As such, AMPK is not only a recipient of hormonal signals but can also be an upstream regulator. Our data suggest that some of the physiological phenotypes previously attributed to peripheral AAK-2 activity on metabolic targets may instead be due to the role of this kinase in neural serotonin signaling.
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Affiliation(s)
- Katherine A. Cunningham
- Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Aude D. Bouagnon
- Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Alexandre G. Barros
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lin Lin
- Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Leandro Malard
- Departamento de Física, Instituto de Ciências Exatas da Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marco Aurélio Romano-Silva
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Kaveh Ashrafi
- Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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Dopamine signaling in C. elegans is mediated in part by HLH-17-dependent regulation of extracellular dopamine levels. G3-GENES GENOMES GENETICS 2014; 4:1081-9. [PMID: 24709946 PMCID: PMC4065251 DOI: 10.1534/g3.114.010819] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In Caenorhabditis elegans, the dopamine transporter DAT-1 regulates synaptic dopamine (DA) signaling by controlling extracellular DA levels. In dat-1(ok157) animals, DA is not taken back up presynaptically but instead reaches extrasynpatic sites, where it activates the dopamine receptor DOP-3 on choligeneric motor neurons and causes animals to become paralyzed in water. This phenotype is called swimming-induced paralysis (SWIP) and is dependent on dat-1 and dop-3. Upstream regulators of dat-1 and dop-3 have yet to be described in C. elegans. In our previous studies, we defined a role for HLH-17 during dopamine response through its regulation of the dopamine receptors. Here we continue our characterization of the effects of HLH-17 on dopamine signaling. Our results suggest that HLH-17 acts downstream of dopamine synthesis to regulate the expression of dop-3 and dat-1. First, we show that hlh-17 animals display a SWIP phenotype that is consistent with its regulation of dop-3 and dat-1. Second, we show that this behavior is enhanced by treatment with the dopamine reuptake inhibitor, bupropion, in both hlh-17 and dat-1 animals, a result suggesting that SWIP behavior is regulated via a mechanism that is both dependent on and independent of DAT-1. Third, and finally, we show that although the SWIP phenotype of hlh-17 animals is unresponsive to the dopamine agonist, reserpine, and to the antidepressant, fluoxetine, hlh-17 animals are not defective in acetylcholine signaling. Taken together, our work suggests that HLH-17 is required to maintain normal levels of dopamine in the synaptic cleft through its regulation of dop-3 and dat-1.
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Barros AGDA, Bridi JC, de Souza BR, de Castro Júnior C, de Lima Torres KC, Malard L, Jorio A, de Miranda DM, Ashrafi K, Romano-Silva MA. Dopamine signaling regulates fat content through β-oxidation in Caenorhabditis elegans. PLoS One 2014; 9:e85874. [PMID: 24465759 PMCID: PMC3899111 DOI: 10.1371/journal.pone.0085874] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 12/06/2013] [Indexed: 11/26/2022] Open
Abstract
The regulation of energy balance involves an intricate interplay between neural mechanisms that respond to internal and external cues of energy demand and food availability. Compelling data have implicated the neurotransmitter dopamine as an important part of body weight regulation. However, the precise mechanisms through which dopamine regulates energy homeostasis remain poorly understood. Here, we investigate mechanisms through which dopamine modulates energy storage. We showed that dopamine signaling regulates fat reservoirs in Caenorhabditis elegans. We found that the fat reducing effects of dopamine were dependent on dopaminergic receptors and a set of fat oxidation enzymes. Our findings reveal an ancient role for dopaminergic regulation of fat and suggest that dopamine signaling elicits this outcome through cascades that ultimately mobilize peripheral fat depots.
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Affiliation(s)
- Alexandre Guimarães de Almeida Barros
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Jessika Cristina Bridi
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Bruno Rezende de Souza
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Célio de Castro Júnior
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Karen Cecília de Lima Torres
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Leandro Malard
- Departamento de Física, Instituto de Ciências Exatas da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ado Jorio
- Departamento de Física, Instituto de Ciências Exatas da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Débora Marques de Miranda
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Kaveh Ashrafi
- Department of Physiology, University of California San Francisco, San Francisco, California, United States
| | - Marco Aurélio Romano-Silva
- Instituto Nacional de Ciência e Tecnologia de Medicina Molecular, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Gardner M, Rosell M, Myers EM. Measuring the effects of bacteria on C. elegans behavior using an egg retention assay. J Vis Exp 2013:e51203. [PMID: 24192811 PMCID: PMC3948155 DOI: 10.3791/51203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
C. elegans egg-laying behavior is affected by environmental cues such as osmolarity and vibration. In the total absence of food C. elegans also cease egg-laying and retain fertilized eggs in their uterus. However, the effect of different sources of food, especially pathogenic bacteria and particularly Enterococcus faecalis, on egg-laying behavior is not well characterized. The egg-in-worm (EIW) assay is a useful tool to quantify the effects of different types of bacteria, in this case E. faecalis, on egg- laying behavior. EIW assays involve counting the number of eggs retained in the uterus of C. elegans. The EIW assay involves bleaching staged, gravid adult C. elegans to remove the cuticle and separate the retained eggs from the animal. Prior to bleaching, worms are exposed to bacteria (or any type of environmental cue) for a fixed period of time. After bleaching, one is very easily able to count the number of eggs retained inside the uterus of the worms. In this assay, a quantifiable increase in egg retention after E. faecalis exposure can be easily measured. The EIW assay is a behavioral assay that may be used to screen for potentially pathogenic bacteria or the presence of environmental toxins. In addition, the EIW assay may be a tool to screen for drugs that affect neurotransmitter signaling since egg-laying behavior is modulated by neurotransmitters such as serotonin and acetylcholine.
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Affiliation(s)
- Mona Gardner
- Department of Biological and Allied Health Sciences, Fairleigh Dickinson University
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Gulbins E, Palmada M, Reichel M, Lüth A, Böhmer C, Amato D, Müller CP, Tischbirek CH, Groemer TW, Tabatabai G, Becker KA, Tripal P, Staedtler S, Ackermann TF, van Brederode J, Alzheimer C, Weller M, Lang UE, Kleuser B, Grassmé H, Kornhuber J. Acid sphingomyelinase-ceramide system mediates effects of antidepressant drugs. Nat Med 2013; 19:934-8. [PMID: 23770692 DOI: 10.1038/nm.3214] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 04/23/2013] [Indexed: 01/18/2023]
Abstract
Major depression is a highly prevalent severe mood disorder that is treated with antidepressants. The molecular targets of antidepressants require definition. We investigated the role of the acid sphingomyelinase (Asm)-ceramide system as a target for antidepressants. Therapeutic concentrations of the antidepressants amitriptyline and fluoxetine reduced Asm activity and ceramide concentrations in the hippocampus, increased neuronal proliferation, maturation and survival and improved behavior in mouse models of stress-induced depression. Genetic Asm deficiency abrogated these effects. Mice overexpressing Asm, heterozygous for acid ceramidase, treated with blockers of ceramide metabolism or directly injected with C16 ceramide in the hippocampus had higher ceramide concentrations and lower rates of neuronal proliferation, maturation and survival compared with controls and showed depression-like behavior even in the absence of stress. The decrease of ceramide abundance achieved by antidepressant-mediated inhibition of Asm normalized these effects. Lowering ceramide abundance may thus be a central goal for the future development of antidepressants.
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Affiliation(s)
- Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.
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Postsynaptic ERG potassium channels limit muscle excitability to allow distinct egg-laying behavior states in Caenorhabditis elegans. J Neurosci 2013; 33:761-75. [PMID: 23303953 DOI: 10.1523/jneurosci.3896-12.2013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Caenorhabditis elegans regulates egg laying by alternating between an inactive phase and a serotonin-triggered active phase. We found that the conserved ERG [ether-a-go-go (EAG) related gene] potassium channel UNC-103 enables this two-state behavior by limiting excitability of the egg-laying muscles. Using both high-speed video recording and calcium imaging of egg-laying muscles in behaving animals, we found that the muscles appear to be excited at a particular phase of each locomotor body bend. During the inactive phase, this rhythmic excitation infrequently evokes calcium transients or contraction of the egg-laying muscles. During the serotonin-triggered active phase, however, these muscles are more excitable and each body bend is accompanied by a calcium transient that drives twitching or full contraction of the egg-laying muscles. We found that ERG-null mutants lay eggs too frequently, and that ERG function is necessary and sufficient in the egg-laying muscles to limit egg laying. ERG K(+) channels localize to postsynaptic sites in the egg-laying muscle, and mutants lacking ERG have more frequent calcium transients and contractions of the egg-laying muscles even during the inactive phase. Thus ERG channels set postsynaptic excitability at a threshold so that further adjustments of excitability by serotonin generate two distinct behavioral states.
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Aitlhadj L, Stürzenbaum SR. The toxicological assessment of two anti-obesity drugs in C. elegans. Toxicol Res (Camb) 2013. [DOI: 10.1039/c2tx20096a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Sharanya D, Thillainathan B, Marri S, Bojanala N, Taylor J, Flibotte S, Moerman DG, Waterston RH, Gupta BP. Genetic control of vulval development in Caenorhabditis briggsae. G3 (BETHESDA, MD.) 2012; 2:1625-41. [PMID: 23275885 PMCID: PMC3516484 DOI: 10.1534/g3.112.004598] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 10/19/2012] [Indexed: 01/23/2023]
Abstract
The nematode Caenorhabditis briggsae is an excellent model organism for the comparative analysis of gene function and developmental mechanisms. To study the evolutionary conservation and divergence of genetic pathways mediating vulva formation, we screened for mutations in C. briggsae that cause the egg-laying defective (Egl) phenotype. Here, we report the characterization of 13 genes, including three that are orthologs of Caenorhabditis elegans unc-84 (SUN domain), lin-39 (Dfd/Scr-related homeobox), and lin-11 (LIM homeobox). Based on the morphology and cell fate changes, the mutants were placed into four different categories. Class 1 animals have normal-looking vulva and vulva-uterine connections, indicating defects in other components of the egg-laying system. Class 2 animals frequently lack some or all of the vulval precursor cells (VPCs) due to defects in the migration of P-cell nuclei into the ventral hypodermal region. Class 3 animals show inappropriate fusion of VPCs to the hypodermal syncytium, leading to a reduced number of vulval progeny. Finally, class 4 animals exhibit abnormal vulval invagination and morphology. Interestingly, we did not find mutations that affect VPC induction and fates. Our work is the first study involving the characterization of genes in C. briggsae vulva formation, and it offers a basis for future investigations of these genes in C. elegans.
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Affiliation(s)
- Devika Sharanya
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Sujatha Marri
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Jon Taylor
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Stephane Flibotte
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Donald G. Moerman
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert H. Waterston
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195-5065
| | - Bhagwati P. Gupta
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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Gürel G, Gustafson MA, Pepper JS, Horvitz HR, Koelle MR. Receptors and other signaling proteins required for serotonin control of locomotion in Caenorhabditis elegans. Genetics 2012; 192:1359-71. [PMID: 23023001 PMCID: PMC3512144 DOI: 10.1534/genetics.112.142125] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 09/15/2012] [Indexed: 01/05/2023] Open
Abstract
A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans uses serotonin as a neurotransmitter to regulate locomotion, providing a genetic system to analyze serotonin signaling. From large-scale genetic screens we identified 36 mutants of C. elegans in which serotonin fails to have its normal effect of slowing locomotion, and we molecularly identified eight genes affected by 19 of the mutations. Two of the genes encode the serotonin-gated ion channel MOD-1 and the G-protein-coupled serotonin receptor SER-4. mod-1 is expressed in the neurons and muscles that directly control locomotion, while ser-4 is expressed in an almost entirely non-overlapping set of sensory and interneurons. The cells expressing the two receptors are largely not direct postsynaptic targets of serotonergic neurons. We analyzed animals lacking or overexpressing the receptors in various combinations using several assays for serotonin response. We found that the two receptors act in parallel to affect locomotion. Our results show that serotonin functions as an extrasynaptic signal that independently activates multiple receptors at a distance from its release sites and identify at least six additional proteins that appear to act with serotonin receptors to mediate serotonin response.
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Affiliation(s)
- Güliz Gürel
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Megan A. Gustafson
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Judy S. Pepper
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
| | - H. Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Michael R. Koelle
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
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McLaggan D, Amezaga MR, Petra E, Frost A, Duff EI, Rhind SM, Fowler PA, Glover LA, Lagido C. Impact of sublethal levels of environmental pollutants found in sewage sludge on a novel Caenorhabditis elegans model biosensor. PLoS One 2012; 7:e46503. [PMID: 23056324 PMCID: PMC3463613 DOI: 10.1371/journal.pone.0046503] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 08/31/2012] [Indexed: 01/12/2023] Open
Abstract
A transgenic strain of the model nematode Caenorhabditis elegans in which bioluminescence reports on relative, whole-organism ATP levels was used to test an environmentally-relevant mixture of pollutants extracted from processed sewage sludge. Changes in bioluminescence, following exposure to sewage sludge extract, were used to assess relative ATP levels and overall metabolic health. Reproductive function and longevity were also monitored. A short (up to 8 h) sublethal exposure of L4 larval stage worms to sewage sludge extract had a concentration-dependent, detrimental effect on energy status, with bioluminescence decreasing to 50-60% of the solvent control (1% DMSO). Following longer exposure (22-24 h), the energy status of the nematodes showed recovery as assessed by bioluminescence. Continuous exposure to sewage sludge extract from the L4 stage resulted in a shorter median lifespan relative to that of solvent or medium control animals, but only in the presence of 400-600 µM 5-fluoro-2'-deoxyuridine (FUdR), which was incorporated to inhibit reproduction. This indicated that FUdR increased lifespan, and that the effect was counteracted by SSE. Exposure to sewage sludge extract from the L1 stage led to slower growth and a delayed onset of egg laying. When L1 exposed nematodes reached the reproductive stage, no effect on egg laying rate or egg number in the uterus was observed. DMSO itself (1%) had a significant inhibitory effect on growth and development of C. elegans exposed from the L1 stage and on reproduction when exposed from the L4 stage. Results demonstrate subtle adverse effects on C. elegans of a complex mixture of environmental pollutants that are present, individually, in very low concentrations and indicate that our biosensor of energy status is a novel, sensitive, rapid, quantitative, whole-organism test system which is suitable for high throughput risk assessment of complex pollutant mixtures.
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Affiliation(s)
- Debbie McLaggan
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
- * E-mail: (DM); (CL)
| | - Maria R. Amezaga
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Eleni Petra
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Andrew Frost
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Elizabeth I. Duff
- Biomathematics and Statistics Scotland, Aberdeen, Scotland, United Kingdom
| | | | - Paul A. Fowler
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - L. Anne Glover
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Cristina Lagido
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
- * E-mail: (DM); (CL)
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65
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Hsu PCL, O'Callaghan M, Al-Salim N, Hurst MRH. Quantum dot nanoparticles affect the reproductive system of Caenorhabditis elegans. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:2366-2374. [PMID: 22847876 DOI: 10.1002/etc.1967] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/31/2012] [Accepted: 06/14/2012] [Indexed: 06/01/2023]
Abstract
Quantum dots (QDs) are an increasingly important class of nanoparticle, but little ecotoxicological data for QDs has been published to date. The effects of mercaptosuccinic acid (MSA)-capped QDs (QDs-MSA) and equivalent concentrations of cadmium (Cd) from cadmium chloride on growth and reproduction of the nematode Caenorhabditis elegans (Rhabditidae) were assessed in laboratory experiments. Growth from larvae to adults of C. elegans was unaffected by exposure to 1 µM fluorescent QDs-MSA, but adults produced more embryos and laid them prematurely. Furthermore, C. elegans exposed to QDs-MSA (1 µM) showed a high percentage of embryo mortality (19.2 ± 0.5, p < 0.001, percentage ± standard deviation) compared with unexposed nematodes (11.6 ± 0.4). An egg-laying defect phenotype was also observed at high frequency in response to 1 µM QDs-MSA exposure (38.3 ± 3.6%, p < 0.01; control 10.0 ± 2.2%). This resulted in a reduced mean life span (20.5 ± 1.1 d, p < 0.05) compared with the control (24.6 ± 1.0 d). Cadmium also caused reduced life span in C. elegans, but a low incidence of egg-laying defects was observed, suggesting that Cd and QDs-MSA affected C. elegans by different mechanisms. Furthermore, egg-laying defects caused by QDs-MSA responded to the addition of the anticonvulsant ethosuximide and to a lesser extent to the neurotransmitter serotonin, suggesting that QDs-MSA might have disrupted motor neurons during the reproduction process.
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66
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Myers EM. Gαo and Gαq regulate the expression of daf-7, a TGFβ-like gene, in Caenorhabditis elegans. PLoS One 2012; 7:e40368. [PMID: 22808145 PMCID: PMC3394784 DOI: 10.1371/journal.pone.0040368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/07/2012] [Indexed: 11/20/2022] Open
Abstract
Caenorhabditis elegans enter an alternate developmental stage called dauer in unfavorable conditions such as starvation, overcrowding, or high temperature. Several evolutionarily conserved signaling pathways control dauer formation. DAF-7/TGFβ and serotonin, important ligands in these signaling pathways, affect not only dauer formation, but also the expression of one another. The heterotrimeric G proteins GOA-1 (Gαo) and EGL-30 (Gαq) mediate serotonin signaling as well as serotonin biosynthesis in C. elegans. It is not known whether GOA-1 or EGL-30 also affect dauer formation and/or daf-7 expression, which are both modulated in part by serotonin. The purpose of this study is to better understand the relationship between proteins important for neuronal signaling and developmental plasticity in both C. elegans and humans. Using promoter-GFP transgenic worms, it was determined that both goa-1 and egl-30 regulate daf-7 expression during larval development. In addition, the normal daf-7 response to high temperature or starvation was altered in goa-1 and egl-30 mutants. Despite the effect of goa-1 and egl-30 mutations on daf-7 expression in various environmental conditions, there was no effect of the mutations on dauer formation. This paper provides evidence that while goa-1 and egl-30 are important for normal daf-7 expression, mutations in these genes are not sufficient to disrupt dauer formation.
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Affiliation(s)
- Edith M Myers
- Department of Biological and Allied Health Sciences, Fairleigh Dickinson University, College at Florham, Madison, New Jersey, United States of America.
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67
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Omura DT, Clark DA, Samuel ADT, Horvitz HR. Dopamine signaling is essential for precise rates of locomotion by C. elegans. PLoS One 2012; 7:e38649. [PMID: 22719914 PMCID: PMC3374838 DOI: 10.1371/journal.pone.0038649] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 05/14/2012] [Indexed: 11/19/2022] Open
Abstract
Dopamine is an important neuromodulator in both vertebrates and invertebrates. We have found that reduced dopamine signaling can cause a distinct abnormality in the behavior of the nematode C. elegans, which has only eight dopaminergic neurons. Using an automated particle-tracking system for the analysis of C. elegans locomotion, we observed that individual wild-type animals made small adjustments to their speed to maintain constant rates of locomotion. By contrast, individual mutant animals defective in the synthesis of dopamine made larger adjustments to their speeds, resulting in large fluctuations in their rates of locomotion. Mutants defective in dopamine signaling also frequently exhibited both abnormally high and abnormally low average speeds. The ability to make small adjustments to speed was restored to these mutants by treatment with dopamine. These behaviors depended on the D2-like dopamine receptor DOP-3 and the G-protein subunit GOA-1. We suggest that C. elegans and other animals, including humans, might share mechanisms by which dopamine restricts motor activity levels and coordinates movement.
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Affiliation(s)
- Daniel T. Omura
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Damon A. Clark
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Aravinthan D. T. Samuel
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - H. Robert Horvitz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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68
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Dissecting a central flip-flop circuit that integrates contradictory sensory cues in C. elegans feeding regulation. Nat Commun 2012; 3:776. [PMID: 22491324 DOI: 10.1038/ncomms1780] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 03/08/2012] [Indexed: 01/16/2023] Open
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69
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Reserpine modulates neurotransmitter release to extend lifespan and alleviate age-dependent Aβ proteotoxicity in Caenorhabditis elegans. Exp Gerontol 2011; 47:188-97. [PMID: 22212533 DOI: 10.1016/j.exger.2011.12.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 12/14/2011] [Accepted: 12/16/2011] [Indexed: 11/20/2022]
Abstract
Aging is a debilitating process often associated with chronic diseases such as diabetes, cardiovascular and neurodegenerative diseases like Alzheimer's disease (AD). AD occurs at a very high incidence posing a huge burden to the society. Model organisms such as C. elegans become essential to understand aging or lifespan extension - the etiology, molecular mechanism and identification of new drugs against age associated diseases. The AD model, manifesting Aβ proteotoxicity, in C. elegans is well established and has provided valuable insights. Earlier, we have reported that Reserpine, an FDA-approved antihypertensive drug, increases C. elegans lifespan with a high quality of life and ameliorates Aβ toxicity in C. elegans. But reserpine does not seem to act through the known lifespan extension pathways or inhibition of its known target, vesicular monoamine transporter, VMAT. Reserpine's mode of action and the pathways it activates are not known. Here, we have evaluated the presynaptic neurotransmitter(s) release pathway and identified acetylcholine (ACh) as the crucial player for reserpine's action. The corroborating evidences are: i) lack of lifespan extension in the ACh loss of function (hypomorphic) - synthesis (cha-1) and transport (unc-17) mutants; ii) mitigation of chronic aldicarb effect; iii) lifespan extension in dopamine (cat-2) and dopamine and serotonin (bas-1) biosynthetic mutants; iv) no rescue from exogenous serotonin induced paralysis in the AD model worms; upon reserpine treatment. Thus, modulation of acetylcholine is essential for reserpine's action.
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70
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Tak YK, Naoghare PK, Han E, Song JM. VEGF inhibitor (Iressa) arrests histone deacetylase expression: single-cell cotransfection imaging cytometry for multi-target-multi-drug analysis. J Cell Physiol 2011; 226:2115-22. [PMID: 21520063 DOI: 10.1002/jcp.22540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multi-target-multi-drug approaches are needed to accelerate the process of drug discovery screening and to design efficient therapeutic strategies against diseases that involve alterations in multiple cellular targets. Herein we report single-cell cotransfection imaging cytometry to quantitatively screen drug-induced off-target effects. Vascular endothelial growth factor (VEGF) and histone deacetylase (HDAC) genes amplified from the genomic DNA were cloned in fluorescently tagged gene constructs (RFP-HDAC/YFP-VEGF). These gene constructs were cotransfected in HEK-293 cells to explore the possibility of off-target effects of 4-phenylbutyrate and Iressa on the expression of VEGF and HDAC through single-cell imaging cytometry. Iressa (10 µM) treatment at the time of cotransfection or 48 h after cotransfection of RFP-HDAC/YFP-VEGF plasmids in HEK-293 cells resulted in off-target effects on HDAC expression. These results suggest possible applications of Iressa in the treatment of diseases in which expression of both HDAC and VEGF should be inhibited. 4-Phenylbutyrate (2.0 mM) did not show any off-target effects on VEGF expression. The developed quantitative multicolor live single-cell cotransfection imaging can be employed to select better drug combinations for faster screening and greater accuracy in multi-target-multi-drug analysis by increasing the on-target/desired off-target effects and eliminating the undesirable off-target effects.
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Affiliation(s)
- Yu Kyung Tak
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, South Korea
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71
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Wang X, Sliwoski GR, Buttner EA. The relevance of Caenorhabditis elegans genetics for understanding human psychiatric disease. Harv Rev Psychiatry 2011; 19:210-8. [PMID: 21790269 DOI: 10.3109/10673229.2011.599185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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72
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Felton CM, Johnson CM. Modulation of dopamine-dependent behaviors by the Caenorhabditis elegans Olig homolog HLH-17. J Neurosci Res 2011; 89:1627-36. [DOI: 10.1002/jnr.22694] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 04/12/2011] [Accepted: 04/15/2011] [Indexed: 11/08/2022]
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73
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Karmacharya R, Lynn SK, Demarco S, Ortiz A, Wang X, Lundy MY, Xie Z, Cohen BM, Miller GM, Buttner EA. Behavioral effects of clozapine: involvement of trace amine pathways in C. elegans and M. musculus. Brain Res 2011; 1393:91-9. [PMID: 21529784 PMCID: PMC3107707 DOI: 10.1016/j.brainres.2011.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 04/02/2011] [Accepted: 04/04/2011] [Indexed: 11/27/2022]
Abstract
Clozapine is an antipsychotic medication with superior efficacy in treatment refractory schizophrenia. The molecular basis of clozapine's therapeutic profile is not well understood. We studied behavioral effects of clozapine in Caenorhabditis elegans to identify novel pathways that modulate clozapine's biological effects. Clozapine stimulated egg laying in C. elegans in a dose-dependent manner. This effect was clozapine-specific, as it was not observed with exposure to a typical antipsychotic, haloperidol or an atypical antipsychotic, olanzapine. A candidate gene screen of biogenic amine neurotransmitter systems identified signaling pathways that mediate this clozapine-specific effect on egg laying. Specifically, we found that clozapine-induced increase in egg laying requires tyramine biosynthesis. To test the implications of this finding across species, we explored whether trace amine systems modulate clozapine's behavioral effects in mammals by studying trace amine-associated receptor 1 (TAAR1) knockout mice. Clozapine increased prepulse inhibition (PPI) in wild-type mice. This increase in PPI was abrogated in TAAR1 knockout mice, implicating TAAR1 in clozapine-induced PPI enhancement. In transfected mammalian cell lines, we found no TAAR activation by antipsychotics, suggesting that modulation of trace amine signaling in mice does not occur directly at the receptor itself. In summary, we report a heretofore-unknown role for trace amine systems in clozapine-mediated effects across two species: C. elegans and mice.
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Affiliation(s)
- Rakesh Karmacharya
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
- Chemical Biology Program, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, MA 02142 USA
| | - Spencer K. Lynn
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
- Department of Psychology, Boston College, Chestnut Hill, MA 02467 USA
| | - Sarah Demarco
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Angelica Ortiz
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Xin Wang
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Miriam Y. Lundy
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Zhihua Xie
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Division of Neuroscience, New England Primate Research Center, Southborough, MA 01772 USA
| | - Bruce M. Cohen
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Gregory M. Miller
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Division of Neuroscience, New England Primate Research Center, Southborough, MA 01772 USA
| | - Edgar A. Buttner
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115 USA
- Mailman Research Center and Frazier Research Institute, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
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74
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Schreiber MA, McIntire SL. A Caenorhabditis elegans p38 MAP kinase pathway mutant protects from dopamine, methamphetamine, and MDMA toxicity. Neurosci Lett 2011; 498:99-103. [PMID: 21565252 DOI: 10.1016/j.neulet.2011.04.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 04/27/2011] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
Biogenic amine systems are damaged by amphetamine abuse and in Parkinson's disease. The mechanisms mediating this damage are of high importance because of the public health impact of these problems. Here we have taken advantage of the Caenorhabditis elegans nematode model system to investigate genetic modifiers of biogenic amine toxicity. In a forward genetic screen, we identified a mutant resistant to the toxic effects of dopamine. This mutant was also resistant to toxic doses of methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA). In addition, this mutation conferred resistance to 6-hydroxydopamine damage to dopaminergic neurons in a Parkinson's disease model. Resistance was due to a mutation in the nsy-1 gene, orthologous to the mammalian ASK-1 MAPKKK. NSY-1 is in the highly conserved p38 MAP kinase pathway, which plays a crucial role in C. elegans innate immunity, suggesting that this pathway may play a role in biogenic amine toxicity system damage due to amphetamines and in the pathogenesis of Parkinson's disease in higher organisms.
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Affiliation(s)
- Matthew A Schreiber
- Ernest Gallo Clinic and Research Center, University of California, San Francisco, 5858 Horton Street Suite 200, Emeryville, CA 94608, United States.
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75
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Hulme SE, Whitesides GM. Die Chemie und der Wurm: Caenorhabditis elegans als Plattform für das Zusammenführen von chemischer und biologischer Forschung. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201005461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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76
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Hulme SE, Whitesides GM. Chemistry and the Worm: Caenorhabditis elegans as a Platform for Integrating Chemical and Biological Research. Angew Chem Int Ed Engl 2011; 50:4774-807. [DOI: 10.1002/anie.201005461] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Indexed: 12/15/2022]
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77
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Kullyev A, Dempsey CM, Miller S, Kuan CJ, Hapiak VM, Komuniecki RW, Griffin CT, Sze JY. A genetic survey of fluoxetine action on synaptic transmission in Caenorhabditis elegans. Genetics 2010; 186:929-41. [PMID: 20739712 PMCID: PMC2975281 DOI: 10.1534/genetics.110.118877] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 08/13/2010] [Indexed: 11/18/2022] Open
Abstract
Fluoxetine is one of the most commonly prescribed medications for many behavioral and neurological disorders. Fluoxetine acts primarily as an inhibitor of the serotonin reuptake transporter (SERT) to block the removal of serotonin from the synaptic cleft, thereby enhancing serotonin signals. While the effects of fluoxetine on behavior are firmly established, debate is ongoing whether inhibition of serotonin reuptake is a sufficient explanation for its therapeutic action. Here, we provide evidence of two additional aspects of fluoxetine action through genetic analyses in Caenorhabditis elegans. We show that fluoxetine treatment and null mutation in the sole SERT gene mod-5 eliminate serotonin in specific neurons. These neurons do not synthesize serotonin but import extracellular serotonin via MOD-5/SERT. Furthermore, we show that fluoxetine acts independently of MOD-5/SERT to regulate discrete properties of acetylcholine (Ach), gamma-aminobutyric acid (GABA), and glutamate neurotransmission in the locomotory circuit. We identified that two G-protein-coupled 5-HT receptors, SER-7 and SER-5, antagonistically regulate the effects of fluoxetine and that fluoxetine binds to SER-7. Epistatic analyses suggest that SER-7 and SER-5 act upstream of AMPA receptor GLR-1 signaling. Our work provides genetic evidence that fluoxetine may influence neuronal functions and behavior by directly targeting serotonin receptors.
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Affiliation(s)
- Andrey Kullyev
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Catherine M. Dempsey
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Sarah Miller
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Chih-Jen Kuan
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Vera M. Hapiak
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Richard W. Komuniecki
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Christine T. Griffin
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Ji Ying Sze
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Biology, National University of Ireland, Maynooth, County Kilare, Ireland Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
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78
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Weeks KR, Dwyer DS, Aamodt EJ. Antipsychotic drugs activate the C. elegans akt pathway via the DAF-2 insulin/IGF-1 receptor. ACS Chem Neurosci 2010; 1:463-73. [PMID: 22778838 DOI: 10.1021/cn100010p] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 03/15/2010] [Indexed: 01/23/2023] Open
Abstract
The molecular modes of action of antipsychotic drugs are poorly understood beyond their effects at the dopamine D2 receptor. Previous studies have placed Akt signaling downstream of D2 dopamine receptors, and recent data have suggested an association between psychotic illnesses and defective Akt signaling. To characterize the effect of antipsychotic drugs on the Akt pathway, we used the model organism C. elegans, a simple system where the Akt/forkhead box O transcription factor (FOXO) pathway has been well characterized. All major classes of antipsychotic drugs increased signaling through the insulin/Akt/FOXO pathway, whereas four other drugs that are known to affect the central nervous system did not. The antipsychotic drugs inhibited dauer formation, dauer recovery, and shortened lifespan, three biological processes affected by Akt signaling. Genetic analysis showed that AKT-1 and the insulin and insulin-like growth factor receptor, DAF-2, were required for the antipsychotic drugs to increase signaling. Serotonin synthesis was partially involved, whereas the mitogen activated protein kinase (MAPK), SEK-1 is a MAP kinase kinase (MAPKK), and calcineurin were not involved. This is the first example of a common but specific molecular effect produced by all presently known antipsychotic drugs in any biological system. Because untreated schizophrenics have been reported to have low levels of Akt signaling, increased Akt signaling might contribute to the therapeutic actions of antipsychotic drugs.
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Affiliation(s)
- Kathrine R. Weeks
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
| | - Donard S. Dwyer
- Department of Psychiatry and Department of Pharmacology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
| | - Eric J. Aamodt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
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79
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Govorunova EG, Moussaif M, Kullyev A, Nguyen KCQ, McDonald TV, Hall DH, Sze JY. A homolog of FHM2 is involved in modulation of excitatory neurotransmission by serotonin in C. elegans. PLoS One 2010; 5:e10368. [PMID: 20442779 PMCID: PMC2860991 DOI: 10.1371/journal.pone.0010368] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Accepted: 03/30/2010] [Indexed: 01/13/2023] Open
Abstract
The C. elegans eat-6 gene encodes a Na(+), K(+)-ATPase alpha subunit and is a homolog of the familial hemiplegic migraine candidate gene FHM2. Migraine is the most common neurological disorder linked to serotonergic dysfunction. We sought to study the pathophysiological mechanisms of migraine and their relation to serotonin (5-HT) signaling using C. elegans as a genetic model. In C. elegans, exogenous 5-HT inhibits paralysis induced by the acetylcholinesterase inhibitor aldicarb. We found that the eat-6(ad467) mutation or RNAi of eat-6 increases aldicarb sensitivity and causes complete resistance to 5-HT treatment, indicating that EAT-6 is a component of the pathway that couples 5-HT signaling and ACh neurotransmission. While a postsynaptic role of EAT-6 at the bodywall NMJs has been well established, we found that EAT-6 may in addition regulate presynaptic ACh neurotransmission. We show that eat-6 is expressed in ventral cord ACh motor neurons, and that cell-specific RNAi of eat-6 in the ACh neurons leads to hypersensitivity to aldicarb. Electron microscopy showed an increased number of synaptic vesicles in the ACh neurons in the eat-6(ad467) mutant. Genetic analyses suggest that EAT-6 interacts with EGL-30 Galphaq, EGL-8 phospholipase C and SLO-1 BK channel signaling to modulate ACh neurotransmission and that either reduced or excessive EAT-6 function may lead to increased ACh neurotransmission. Study of the interaction between eat-6 and 5-HT receptors revealed both stimulatory and inhibitory 5-HT inputs to the NMJs. We show that the inhibitory and stimulatory 5-HT signals arise from distinct 5-HT neurons. The role of eat-6 in modulation of excitatory neurotransmission by 5-HT may provide a genetic explanation for the therapeutic effects of the drugs targeting 5-HT receptors in the treatment of migraine patients.
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Affiliation(s)
- Elena G. Govorunova
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mustapha Moussaif
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Andrey Kullyev
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ken C. Q. Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Thomas V. McDonald
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - David H. Hall
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ji Y. Sze
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Keowkase R, Aboukhatwa M, Luo Y. Fluoxetine protects against amyloid-beta toxicity, in part via daf-16 mediated cell signaling pathway, in Caenorhabditis elegans. Neuropharmacology 2010; 59:358-65. [PMID: 20420844 DOI: 10.1016/j.neuropharm.2010.04.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 03/26/2010] [Accepted: 04/07/2010] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common form of dementia in elderly people. The accumulation of amyloid beta (Abeta) is one of the histopathological hallmarks of AD. Abeta is aggregated to form oligomers which are toxic to neurons and are critical to the onset and progression of AD. In a Caenorhabditis elegans (C. elegans) model of AD, human Abeta is expressed intracellularly in the body wall muscle. The expression and subsequent aggregation of Abeta in the muscle lead to progressive paralysis. Although the mechanism of action is unknown, antidepressants have been used with FDA approved drugs for dementia in AD and have been shown to enhance cognitive function in human and in animal models of AD. We found that the antidepressant fluoxetine, a selective serotonin reuptake inhibitor, significantly delayed Abeta-induced paralysis in the C. elegans model of Abeta toxicity by reducing Abeta oligomers. Our results showed that insulin signaling and DAF-16/FOXO transcription factors were required for fluoxetine-mediated delayed paralysis. We also found that fluoxetine increased thermal stress resistance and extended life span. These findings suggests that fluoxetine may have benefit for the treatment of AD by the reduction of proteotoxicity.
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Affiliation(s)
- Roongpetch Keowkase
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA
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81
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Affiliation(s)
- Peter J Schlueter
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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82
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Brown MK, Luo Y. Bilobalide modulates serotonin-controlled behaviors in the nematode Caenorhabditis elegans. BMC Neurosci 2009; 10:62. [PMID: 19545409 PMCID: PMC2714043 DOI: 10.1186/1471-2202-10-62] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 06/22/2009] [Indexed: 11/16/2022] Open
Abstract
Background Dysfunctions in the serotonergic system have been implicated in several neurological disorders such as depression. Elderly individuals who have been diagnosed with clinical depression show elevated cases of neurodegenerative diseases. This has led to suggestions that modulating the serotonin (5-HT) system could provide an alternative method to current therapies for alleviating these pathologies. The neuroprotective effects of bilobalide in vitro have been documented. We aim to determine whether bilobalide affects the 5-HT system in the nematode C. elegans. The wild type worms, as well as well-characterized 5-HT mutants, were fed with bilobalide in a range of concentrations, and several 5-HT controlled behaviors were tested. Results We observed that bilobalide significantly inhibited 5-HT-controlled egg-laying behavior in a dose-dependent manner, which was blocked in the 5-HT receptor mutants (ser-4, mod-1), but not in the 5-HT transporter (mod-5) or synthesis (tph-1) mutants. Bilobalide also potentiated a 5-HT-controlled, experience-dependent locomotory behavior, termed the enhanced slowing response in the wild type animals. However, this effect was fully blocked in 5-HT receptor mod-1 and dopamine defective cat-2 mutants, but only partially blocked in ser-4 mutants. We also demonstrated that acetylcholine transmission was inhibited in a transgenic C. elegans strain that constitutively expresses Aβ, and bilobalide did not significantly affect this inhibition. Conclusion These results suggest that bilobalide may modulate specific 5-HT receptor subtypes, which involves interplay with dopamine transmission. Additional studies for the function of bilobalide in neurotransmitter systems could aid in our understanding of its neuroprotective properties.
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Affiliation(s)
- Marishka K Brown
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, USA.
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83
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Shpakov AO. Structural functional characteristic of neuronal serotonin receptors and molecular mechanisms of their coupling with G-proteins. NEUROCHEM J+ 2009. [DOI: 10.1134/s1819712409010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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84
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Three distinct amine receptors operating at different levels within the locomotory circuit are each essential for the serotonergic modulation of chemosensation in Caenorhabditis elegans. J Neurosci 2009; 29:1446-56. [PMID: 19193891 DOI: 10.1523/jneurosci.4585-08.2009] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Serotonin modulates behavioral plasticity in both vertebrates and invertebrates and in Caenorhabditis elegans regulates key behaviors, including locomotion, aversive learning and olfaction through at least four different 5-HT receptors. In the present study, we examined the serotonergic stimulation of aversive responses to dilute octanol in animals containing null alleles of these 5-HT receptors. Both ser-1 and mod-1 null animals failed to increase sensitivity to dilute octanol on food/5-HT, in contrast to wild-type, ser-4 or ser-7 null animals. 5-HT sensitivity was restored by the expression of MOD-1 and SER-1 in the AIB or potentially the AIY, and RIA interneurons of mod-1 and ser-1 null animals, respectively. Because none of these 5-HT receptors appear to be expressed in the ASH sensory neurons mediating octanol sensitivity, we identified a 5-HT(6)-like receptor, F16D3.7(SER-5), that was required for food/5-HT-dependent increases in octanol sensitivity. ser-5 null animals failed to increase octanol sensitivity in the presence of food/5-HT and sensitivity could be restored by expression of SER-5 in the ASHs. Similarly, the RNAi knockdown of ser-5 expression in the ASHs of wild-type animals also abolished 5-HT-dependent increases in octanol sensitivity, suggesting that SER-5 modulates the octanol responsiveness of the ASHs directly. Together, these results suggest that multiple amine receptors, functioning at different levels within the locomotory circuit, are each essential for the serotonergic modulation of ASH-mediated aversive responses.
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85
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Zubenko GS, Jones ML, Estevez AO, Hughes HB, Estevez M. Identification of a CREB-dependent serotonergic pathway and neuronal circuit regulating foraging behavior in Caenorhabditis elegans: a useful model for mental disorders and their treatments? Am J Med Genet B Neuropsychiatr Genet 2009; 150B:12-23. [PMID: 19035344 PMCID: PMC3234207 DOI: 10.1002/ajmg.b.30891] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cAMP-response element binding protein (CREB)-mediated cell signaling pathway is conserved through evolution and participates in a broad range of complex behaviors of divergent species including man. This study describes the integration of genetic, pharmacologic, and anatomic methods to elucidate a serotonergic signaling pathway by which the CREB homolog CRH-1 controls foraging rate (FR) in the model organism Caenorhabditis elegans, along with the complete neuronal circuit through which this pathway operates. In the anterior afferent arm of the circuit, CRH-1 controls FR by regulating the expression of tph-1, the sole structural gene for tryptophan hydroxylase, in serotonergic sensory (ADF) neurons whose post-synaptic effects are mediated through 5HT(2)-like SER-1 receptors. The posterior afferent limb of the circuit includes an interneuron (RIH) that does not express tph-1 and whose serotonergic phenotype is dependent on the contribution of this neurotransmitter from another source, probably the ADF neurons. The postsynaptic effects of the RIH interneuron are mediated through 5HT(1)-like SER-4 receptors. This model has potential utility for the study of clinical disorders and experimental therapeutics. Furthermore, the discovery of serotonergic neurons that depend on other sources for their neurotransmitter phenotype could provide a mechanism for rapidly altering the number and distribution of serotonergic pathways in developing and adult nervous systems, providing a dimension of functional complexity that has been previously unrecognized.
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Affiliation(s)
- George S. Zubenko
- Department of Psychiatry University of Pittsburgh School of Medicine, Pittsburgh, PA,Department of Biological Sciences, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA
| | - Michelle L. Jones
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Annette O. Estevez
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Hugh B. Hughes
- Department of Psychiatry University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Miguel Estevez
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA,Department of Veteran's Affairs Medical Center, Pittsburgh, PA
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86
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Hapiak VM, Hobson RJ, Hughes L, Smith K, Harris G, Condon C, Komuniecki P, Komuniecki RW. Dual excitatory and inhibitory serotonergic inputs modulate egg laying in Caenorhabditis elegans. Genetics 2009; 181:153-63. [PMID: 19001289 PMCID: PMC2621164 DOI: 10.1534/genetics.108.096891] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 11/05/2008] [Indexed: 01/30/2023] Open
Abstract
Serotonin (5-HT) regulates key processes in both vertebrates and invertebrates. Previously, four 5-HT receptors that contributed to the 5-HT modulation of egg laying were identified in Caenorhabditis elegans. Therefore, to assess potential receptor interactions, we generated animals containing combinations of null alleles for each receptor, especially animals expressing only individual 5-HT receptors. 5-HT-stimulated egg laying and egg retention correlated well with different combinations of predicted excitatory and inhibitory serotonergic inputs. For example, 5-HT did not stimulate egg laying in ser-1, ser-7, or ser-7 ser-1 null animals, and ser-7 ser-1 animals retained more eggs than wild-type animals. In contrast, 5-HT-stimulated egg laying in ser-4;mod-1 animals was greater than in wild-type animals, and ser-4;mod-1 animals retained fewer eggs than wild-type animals. Surprisingly, ser-4;mod-1;ser-7 ser-1 animals retained the same number of eggs as wild-type animals and exhibited significant 5-HT-stimulated egg laying that was dependent on a previously uncharacterized receptor, SER-5. 5-HT-stimulated egg laying was absent in ser-5;ser-4;mod-1;ser-7 ser-1 animals, and these animals retained more eggs than either wild-type or ser-4;mod-1;ser-7 ser-1 animals. The 5-HT sensitivity of egg laying could be restored by ser-5 muscle expression. Together, these results highlight the dual excitatory/inhibitory serotonergic inputs that combine to modulate egg laying.
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Affiliation(s)
- Vera M Hapiak
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606-3390, USA
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87
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Chen F, Mackerell AD, Luo Y, Shapiro P. Using Caenorhabditis elegans as a model organism for evaluating extracellular signal-regulated kinase docking domain inhibitors. J Cell Commun Signal 2008; 2:81-92. [PMID: 19105050 PMCID: PMC2648047 DOI: 10.1007/s12079-008-0034-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 12/03/2008] [Indexed: 01/13/2023] Open
Abstract
We have recently identified several novel ATP-independent inhibitors that target the extracellular signal-regulated kinase-2 (ERK2) protein and inhibit substrate phosphorylation. To further characterize these compounds, we describe the use of C. elegans as a model organism. C. elegans is recognized as a versatile and cost effective model for use in drug development. These studies take advantage of the well characterized process of vulva development and egg laying, which requires MPK-1, the homolog to human ERK2. It is shown that treatment of C. elegans eggs or larvae prior to vulva formation with a previously identified lead compound (76) caused up to 50% reduction in the number of eggs produced from the adult worm. In contrast, compound 76 had no effect on egg laying in young adult or adult worms with fully formed vulva. The reduction in egg laying by the test compound was not due to effects on C. elegans life span, general toxicity, or non-specific stress. However, compound 76 did show selective inhibition of phosphorylation of LIN-1, a MPK-1 substrate essential for vulva precursor cell formation. Moreover, compound 76 inhibited cell fusion necessary for vulva maturation and reduced the multivulva phenotype in LET-60 (Ras) mutant worms that have constitutive activation of MPK-1. These findings support the use of C. elegans as a model organism to evaluate the selectivity and specificity of novel ERK targeted compounds.
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Affiliation(s)
- Fengming Chen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
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88
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Elle IC, Olsen LC, Mosbech MB, Rødkær SV, Pultz D, Boelt SG, Fredens J, Sørensen P, Færgeman NJ. C. elegans: A Model for Understanding Lipid Accumulation. Lipid Insights 2008. [DOI: 10.4137/lpi.s1057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Regulation and coordination of lipid metabolism involve complex interactions between the feeding regulatory centres in the nervous system and the regulated uptake, intracellular transport, storage, and utilization of stored lipids. As energy is essential to all cellular processes, it is thought that complex networks have evolved to ensure survival by maintaining adequate energy reservoirs. However, in times of nutrient abundance and imbalance, improper regulation and coordination of these networks can lead to obesity and other metabolic diseases and syndromes. Obesity genes must be considered as molecular components of such networks which function at an organismal level to orchestrate energy intake and expenditure. Thus, the functions of obesity genes must be understood within the context of these networks in intact animals. Since the majority of genes required for lipid homeostasis are evolutionarily conserved, much information can be obtained relevant to complex organisms by studying simple eukaryotes like C. elegans. Its genetic tractability makes C. elegans a highly attractive platform for identifying lipid regulatory pathways, drugs, and their molecular targets which ultimately will help us to understand the origin of metabolic diseases such as obesity and diabetes. Here we briefly present some central aspects of lipid accumulation in C. elegans and discuss its merits as a platform for identification and development of novel bioactive compounds regulating lipid storage.
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Affiliation(s)
- Ida C. Elle
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Louise C.B. Olsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Mai-Britt Mosbech
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Steven V. Rødkær
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Dennis Pultz
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Sanne G. Boelt
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Julius Fredens
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Pernille Sørensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Nils Joakim Færgeman
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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89
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Donohoe DR, Phan T, Weeks K, Aamodt EJ, Dwyer DS. Antipsychotic drugs up-regulate tryptophan hydroxylase in ADF neurons of Caenorhabditis elegans: role of calcium-calmodulin-dependent protein kinase II and transient receptor potential vanilloid channel. J Neurosci Res 2008; 86:2553-63. [PMID: 18438926 DOI: 10.1002/jnr.21684] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Antipsychotic drugs produce acute behavioral effects through antagonism of dopamine and serotonin receptors, and long-term adaptive responses that are not well understood. The goal of the study presented here was to use Caenorhabditis elegans to investigate the molecular mechanism or mechanisms that contribute to adaptive responses produced by antipsychotic drugs. First-generation antipsychotics, trifluoperazine and fluphenazine, and second-generation drugs, clozapine and olanzapine, increased the expression of tryptophan hydroxylase-1::green fluorescent protein (TPH-1::GFP) and serotonin in the ADF neurons of C. elegans. This response was absent or diminished in mutant strains lacking the transient receptor potential vanilloid channel (TRPV; osm-9) or calcium/calmodulin-dependent protein kinase II (CaMKII; unc-43). The role of calcium signaling was further implicated by the finding that a selective antagonist of calmodulin and a calcineurin inhibitor also enhanced TPH-1::GFP expression. The ADF neurons modulate foraging behavior (turns/reversals off food) through serotonin production. We found that short-term exposure to the antipsychotic drugs altered the frequency of turns/reversals off food. This response was mediated through dopamine and serotonin receptors and was abolished in serotonin-deficient mutants (tph-1) and strains lacking the SER-1 and MOD-1 serotonin receptors. Consistent with the increase in serotonin in the ADF neurons induced by the drugs, drug withdrawal after 24-hr treatment was accompanied by a rebound in the number of turns/reversals, which demonstrates behavioral adaptation in serotonergic systems. Characterization of the cellular, molecular, and behavioral adaptations to continuous exposure to antipsychotic drugs may provide insight into the long-term clinical effects of these medications.
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Affiliation(s)
- Dallas R Donohoe
- Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Louisiana 71130, USA
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90
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Murakami H, Bessinger K, Hellmann J, Murakami S. Manipulation of serotonin signal suppresses early phase of behavioral aging in Caenorhabditis elegans. Neurobiol Aging 2008; 29:1093-100. [PMID: 17336425 DOI: 10.1016/j.neurobiolaging.2007.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 12/08/2006] [Accepted: 01/23/2007] [Indexed: 11/29/2022]
Abstract
Aging is associated with progressive changes in behavioral functions, in part caused by muscle frailty, called sarcopenia. However, it was not clear whether certain neurotransmitters are directly involved in behavioral aging. Here we investigated aging of locomotion behaviors with an associative learning property, called basal and enhanced slowing response in Caenorhabditis elegans. Basal slowing response is a modest slowdown in response to food, while enhanced slowing response is a greater slowdown response when animals experience starvation. The behaviors are mediated by dopamine and serotonin, respectively. During aging, basal slowing response was increased, resulting in a diminished difference between the two slowing responses. The behavioral change occurred during early phase of aging prior to the timing when sarcopenia was observed in previous studies. Interestingly, expression of a serotonin biosynthesis marker, tph-1Colon, two colonsGFP, was increased in old animals. Serotonin receptor antagonists and deletion mutants of their target receptor genes (ser-1 and ser-4) partially suppressed age-related changes in locomotion behaviors. Thus, manipulating serotonin signal at receptor levels suppresses early phase of locomotion aging.
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Affiliation(s)
- Hana Murakami
- Gheens Center on Aging, Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 580 S Preston Street, BaxterII, RM102, Louisville, KY 40202, United States
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91
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Srinivasan S, Sadegh L, Elle IC, Christensen AGL, Faergeman NJ, Ashrafi K. Serotonin regulates C. elegans fat and feeding through independent molecular mechanisms. Cell Metab 2008; 7:533-44. [PMID: 18522834 PMCID: PMC2495008 DOI: 10.1016/j.cmet.2008.04.012] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 02/12/2008] [Accepted: 04/29/2008] [Indexed: 10/22/2022]
Abstract
We investigated serotonin signaling in C. elegans as a paradigm for neural regulation of energy balance and found that serotonergic regulation of fat is molecularly distinct from feeding regulation. Serotonergic feeding regulation is mediated by receptors whose functions are not required for fat regulation. Serotonergic fat regulation is dependent on a neurally expressed channel and a G protein-coupled receptor that initiate signaling cascades that ultimately promote lipid breakdown at peripheral sites of fat storage. In turn, intermediates of lipid metabolism generated in the periphery modulate feeding behavior. These findings suggest that, as in mammals, C. elegans feeding behavior is regulated by extrinsic and intrinsic cues. Moreover, obesity and thinness are not solely determined by feeding behavior. Rather, feeding behavior and fat metabolism are coordinated but independent responses of the nervous system to the perception of nutrient availability.
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Affiliation(s)
- Supriya Srinivasan
- Department of Physiology and UCSF Diabetes Center, University of California, San Francisco, San Francisco, CA 94158-2517, USA
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92
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Kreke N, Dietrich DR. Physiological endpoints for potential SSRI interactions in fish. Crit Rev Toxicol 2008; 38:215-47. [PMID: 18324517 DOI: 10.1080/10408440801891057] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are among the pharmaceutical compounds frequently detected in sewage treatment plant effluents and surface waters, albeit at very low concentrations, and have therefore become a focus of interest as environmental pollutants. These neuroactive drugs are primarily used in the treatment of depression but have also found broader use as medication for other neurological dysfunctions, consequently resulting in a steady increase of prescriptions worldwide. SSRIs, via inhibition of the serotonin (5-hydroxytryptamine, 5-HT) reuptake mechanism, induce an increase in extracellular 5-HT concentration within the central nervous system of mammals. The phylogenetically ancient and highly conserved neurotransmitter and neurohormone 5-HT has been found in invertebrates and vertebrates, although its specific physiological role and mode of action is unknown for many species. Consequently, it is difficult to assess the impact of chronic SSRI exposure in the environment, especially in the aquatic ecosystem. In view of this, the current knowledge of the functions of 5-HT in fish physiology is reviewed and, via comparison to the physiological role and function of 5-HT in mammals, a characterization of the potential impact of chronic SSRI exposure on fish is provided. Moreover, the insight on the physiological function of 5-HT strongly suggests that the experimental approaches currently used are inadequate if not entirely improper for routine environmental risk assessment of pharmaceuticals (e.g., SSRIs), as relevant endpoints are not assessed or impossible to determine.
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Affiliation(s)
- N Kreke
- Environmental Toxicology, Department of Biology, University of Konstanz, Konstanz, Germany
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93
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Reserpine can confer stress tolerance and lifespan extension in the nematode C. elegans. Biogerontology 2008; 9:309-16. [PMID: 18409080 DOI: 10.1007/s10522-008-9139-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 03/17/2008] [Indexed: 10/22/2022]
Abstract
Though the lifespan extension mechanism is partly understood from C. elegans to mice, a viable pharmacological intervention is not yet feasible. Here, we report that reserpine largely known as an antipsychotic-antihypertensive drug, can extend C. elegans lifespan. Chronic reserpine treatment from embryo stage or young adults extends the C. elegans lifespan robustly at 25 degrees C. Most importantly, the reserpine treated long lived worms are active (locomotion and pharyngeal pumping) for a long time thereby conferring high quality throughout life. Reserpine mediated lifespan extension is independent of the daf-16 pathway and partly requires serotonin. Reserpine treatment makes the worms highly thermotolerant. Thus, in addition to its known function, reserpine is able to provide stress tolerance and lifespan extension in C. elegans.
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94
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Regulation of serotonin biosynthesis by the G proteins Galphao and Galphaq controls serotonin signaling in Caenorhabditis elegans. Genetics 2008; 178:157-69. [PMID: 18202365 DOI: 10.1534/genetics.107.079780] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To analyze mechanisms that modulate serotonin signaling, we investigated how Caenorhabditis elegans regulates the function of serotonergic motor neurons that stimulate egg-laying behavior. Egg laying is inhibited by the G protein Galphao and activated by the G protein Galphaq. We found that Galphao and Galphaq act directly in the serotonergic HSN motor neurons to control egg laying. There, the G proteins had opposing effects on transcription of the tryptophan hydroxylase gene tph-1, which encodes the rate-limiting enzyme for serotonin biosynthesis. Antiserotonin staining confirmed that Galphao and Galphaq antagonistically affect serotonin levels. Altering tph-1 gene dosage showed that small changes in tph-1 expression were sufficient to affect egg-laying behavior. Epistasis experiments showed that signaling through the G proteins has additional tph-1-independent effects. Our results indicate that (1) serotonin signaling is regulated by modulating serotonin biosynthesis and (2) Galphao and Galphaq act in the same neurons to have opposing effects on behavior, in part, by antagonistically regulating transcription of specific genes. Galphao and Galphaq have opposing effects on many behaviors in addition to egg laying and may generally act, as they do in the egg-laying system, to integrate multiple signals and consequently set levels of transcription of genes that affect neurotransmitter release.
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95
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96
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An antidepressant that extends lifespan in adult Caenorhabditis elegans. Nature 2007; 450:553-6. [PMID: 18033297 DOI: 10.1038/nature05991] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 10/11/2007] [Indexed: 12/27/2022]
Abstract
The mechanisms that determine the lifespan of an organism are still largely a mystery. One goal of ageing research is to find drugs that would increase lifespan and vitality when given to an adult animal. To this end, we tested 88,000 chemicals for the ability to extend the lifespan of adult Caenorhabditis elegans nematodes. Here we report that a drug used as an antidepressant in humans increases C. elegans lifespan. In humans, this drug blocks neural signalling by the neurotransmitter serotonin. In C. elegans, the effect of the drug on lifespan is reduced or eradicated by mutations that affect serotonin synthesis, serotonin re-uptake at synapses, or either of two G-protein-coupled receptors: one that recognizes serotonin and the other that detects another neurotransmitter, octopamine. In vitro studies show that the drug acts as an antagonist at both receptors. Testing of the drug on dietary-restricted animals or animals with mutations that affect lifespan indicates that its effect on lifespan involves mechanisms associated with lifespan extension by dietary restriction. These studies indicate that lifespan can be extended by blocking certain types of neurotransmission implicated in food sensing in the adult animal, possibly leading to a state of perceived, although not real, starvation.
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97
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Hihi AK, Beauchamp MC, Branicky R, Desjardins A, Casanova I, Guimond MP, Carroll M, Ethier M, Kianicka I, McBride K, Hekimi S. Evolutionary conservation of drug action on lipoprotein metabolism-related targets. J Lipid Res 2007; 49:74-83. [PMID: 17901468 DOI: 10.1194/jlr.m700167-jlr200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic analysis has shown that the slower than normal rhythmic defecation behavior of the clk-1 mutants of Caenorhabditis elegans is the result of altered lipoprotein metabolism. We show here that this phenotype can be suppressed by drugs that affect lipoprotein metabolism, including drugs that affect HMG-CoA reductase activity, reverse cholesterol transport, or HDL levels. These pharmacological effects are highly specific, as these drugs affect defecation only in clk-1 mutants and not in the wild-type and do not affect other behaviors of the mutants. Furthermore, drugs that affect processes not directly related to lipid metabolism show no or minimal activity. Based on these findings, we carried out a compound screen that identified 190 novel molecules that are active on clk-1 mutants, 15 of which also specifically decrease the secretion of apolipoprotein B (apoB) from HepG2 hepatoma cells. The other 175 compounds are potentially active on lipid-related processes that cannot be targeted in cell culture. One compound, CHGN005, was tested and found to be active at reducing apoB secretion in intestinal Caco-2 cells as well as in HepG2 cells. This compound was also tested in a mouse model of dyslipidemia and found to decrease plasma cholesterol and triglyceride levels. Thus, target processes for pharmacological intervention on lipoprotein synthesis, transport, and metabolism are conserved between nematodes and vertebrates, which allows the use of C. elegans for drug discovery.
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98
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Abstract
The neurotransmitter serotonin has been implicated in affecting the variation of longevity in natural Drosophila populations and age-related diseases in mammals. Based on these observations, it has been predicted that serotonin signal, perhaps at levels of serotonin biosynthesis, may control lifespan. Here, we investigated a variety of mutations in serotonin-signal genes, including serotonin biosynthesis genes, a serotonin transporter gene, and serotonin receptor genes. Despite this prediction, mutations in the serotonin biosynthesis genes had little or modest effects on lifespan, while the mod-5 mutation with increased availability of serotonin caused a modest life-shortening effect. In contrast, a deletion mutation of the ser-1 serotonin receptor gene increased longevity by up to 46%, likely through the insulin/insulin-like growth factor 1 pathway. This result suggests an interaction between the serotonin pathway and the insulin/insulin-like growth factor 1 pathway. A deletion mutation of another serotonin receptor gene, ser-4, shortened early to mid lifespan. The results suggest that serotonin signal antagonistically modulates longevity through different serotonin receptors. This study may indicate serotonin receptors as a potential target for antigeric interventions.
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Affiliation(s)
- Hana Murakami
- Gheens Center on Aging, Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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99
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Speese S, Petrie M, Schuske K, Ailion M, Ann K, Iwasaki K, Jorgensen EM, Martin TFJ. UNC-31 (CAPS) is required for dense-core vesicle but not synaptic vesicle exocytosis in Caenorhabditis elegans. J Neurosci 2007; 27:6150-62. [PMID: 17553987 PMCID: PMC6672138 DOI: 10.1523/jneurosci.1466-07.2007] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous studies indicated that CAPS (calcium-dependent activator protein for secretion) functions as an essential component for the Ca2+-dependent exocytosis of dense-core vesicles in neuroendocrine cells. However, recent mouse knock-out studies suggested an alternative role in the vesicular uptake or storage of catecholamines. To genetically assess the functional role of CAPS, we characterized the sole Caenorhabditis elegans CAPS ortholog UNC-31 (uncoordinated family member) and determined its role in dense-core vesicle-mediated peptide secretion and in synaptic vesicle recycling. Novel assays for dense-core vesicle exocytosis were developed by expressing a prepro-atrial natriuretic factor-green fluorescent protein fusion protein in C. elegans. unc-31 mutants exhibited reduced peptide release in vivo and lacked evoked peptide release in cultured neurons. In contrast, cultured neurons from unc-31 mutants exhibited normal stimulated synaptic vesicle recycling measured by FM4-64 [N-(3-triethylammoniumpropyl)-4-(6-(4-diethylamino)phenyl)hexatrienyl)pyridinium dibromide] dye uptake. Conversely, UNC-13, which exhibits sequence homology to CAPS/UNC-31, was found to be essential for synaptic vesicle but not dense-core vesicle exocytosis. These findings indicate that CAPS/UNC-31 function is not restricted to catecholaminergic vesicles but is generally required for and specific to dense-core vesicle exocytosis. Our results suggest that CAPS/UNC-31 and UNC-13 serve parallel and dedicated roles in dense-core vesicle and synaptic vesicle exocytosis, respectively, in the C. elegans nervous system.
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Affiliation(s)
- Sean Speese
- Department of Biology, University of Utah, Salt Lake City, Utah 84112
| | - Matt Petrie
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, and
| | - Kim Schuske
- Department of Biology, University of Utah, Salt Lake City, Utah 84112
| | - Michael Ailion
- Department of Biology, University of Utah, Salt Lake City, Utah 84112
| | - Kyoungsook Ann
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, and
| | - Kouichi Iwasaki
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, Illinois 60611
| | - Erik M. Jorgensen
- Department of Biology, University of Utah, Salt Lake City, Utah 84112
| | - Thomas F. J. Martin
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, and
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100
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Artal-Sanz M, de Jong L, Tavernarakis N. Caenorhabditis elegans: a versatile platform for drug discovery. Biotechnol J 2007; 1:1405-18. [PMID: 17109493 DOI: 10.1002/biot.200600176] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Drug discovery and drug target identification are two intimately linked facets of intervention strategies aimed at effectively combating pathological conditions in humans. Simple model organisms provide attractive platforms for devising and streamlining efficient drug discovery and drug target identification methodologies. The nematode worm Caenorhabditis elegans has emerged as a particularly convenient and versatile tool that can be exploited to achieve these goals. Although C. elegans is a relatively modern addition to the arsenal of model organisms, its biology has already been investigated to an exceptional level. This, coupled with effortless handling and a notable low cost of cultivation and maintenance, allows seamless implementation of high-throughput drug screening approaches as well as in-depth genetic and biochemical studies of the molecular pathways targeted by specific drugs. In this review, we introduce C. elegans as a model organism with significant advantages toward the identification of molecular drug targets. In addition, we discuss the value of the worm in the development of drug screening and drug evaluation protocols. The unique features of C. elegans, which greatly facilitate drug studies, hold promise for both deciphering disease pathogenesis and formulating educated and effective therapeutic interventions.
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Affiliation(s)
- Marta Artal-Sanz
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas, Crete, Greece
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