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Koopman M, Güngördü L, Janssen L, Seinstra RI, Richmond JE, Okerlund N, Wardenaar R, Islam P, Hogewerf W, Brown AEX, Jorgensen EM, Nollen EAA. Rebalancing the motor circuit restores movement in a Caenorhabditis elegans model for TDP-43 toxicity. Cell Rep 2024; 43:114204. [PMID: 38748878 DOI: 10.1016/j.celrep.2024.114204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 02/29/2024] [Accepted: 04/23/2024] [Indexed: 06/01/2024] Open
Abstract
Amyotrophic lateral sclerosis can be caused by abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm of neurons. Here, we use a C. elegans model for TDP-43-induced toxicity to identify the biological mechanisms that lead to disease-related phenotypes. By applying deep behavioral phenotyping and subsequent dissection of the neuromuscular circuit, we show that TDP-43 worms have profound defects in GABA neurons. Moreover, acetylcholine neurons appear functionally silenced. Enhancing functional output of repressed acetylcholine neurons at the level of, among others, G-protein-coupled receptors restores neurotransmission, but inefficiently rescues locomotion. Rebalancing the excitatory-to-inhibitory ratio in the neuromuscular system by simultaneous stimulation of the affected GABA- and acetylcholine neurons, however, not only synergizes the effects of boosting individual neurotransmitter systems, but instantaneously improves movement. Our results suggest that interventions accounting for the altered connectome may be more efficient in restoring motor function than those solely focusing on diseased neuron populations.
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Affiliation(s)
- Mandy Koopman
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Lale Güngördü
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Leen Janssen
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Renée I Seinstra
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Nathan Okerlund
- Howard Hughes Medical Institute and School of Biological Science, The University of Utah, Salt Lake City, UT, USA
| | - René Wardenaar
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Priota Islam
- MRC London Institute of Medical Sciences, London, UK; Institute of Clinical Sciences, Imperial College London, London, UK
| | - Wytse Hogewerf
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Andre E X Brown
- MRC London Institute of Medical Sciences, London, UK; Institute of Clinical Sciences, Imperial College London, London, UK
| | - Erik M Jorgensen
- Howard Hughes Medical Institute and School of Biological Science, The University of Utah, Salt Lake City, UT, USA
| | - Ellen A A Nollen
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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Ohnishi K, Sokabe T, Miura T, Tominaga M, Ohta A, Kuhara A. G protein-coupled receptor-based thermosensation determines temperature acclimatization of Caenorhabditis elegans. Nat Commun 2024; 15:1660. [PMID: 38396085 PMCID: PMC10891075 DOI: 10.1038/s41467-024-46042-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Animals must sense and acclimatize to environmental temperatures for survival, yet their thermosensing mechanisms other than transient receptor potential (TRP) channels remain poorly understood. We identify a trimeric G protein-coupled receptor (GPCR), SRH-40, which confers thermosensitivity in sensory neurons regulating temperature acclimatization in Caenorhabditis elegans. Systematic knockdown of 1000 GPCRs by RNAi reveals GPCRs involved in temperature acclimatization, among which srh-40 is highly expressed in the ADL sensory neuron, a temperature-responsive chemosensory neuron, where TRP channels act as accessorial thermoreceptors. In vivo Ca2+ imaging demonstrates that an srh-40 mutation reduced the temperature sensitivity of ADL, resulting in supranormal temperature acclimatization. Ectopically expressing SRH-40 in a non-warmth-sensing gustatory neuron confers temperature responses. Moreover, temperature-dependent SRH-40 activation is reconstituted in Drosophila S2R+ cells. Overall, SRH-40 may be involved in thermosensory signaling underlying temperature acclimatization. We propose a dual thermosensing machinery through a GPCR and TRP channels in a single sensory neuron.
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Affiliation(s)
- Kohei Ohnishi
- Graduate school of Natural Science, Konan University, Kobe, Hyogo, 658-8501, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, 658-8501, Japan
- Physiology and Biophysics, Graduate School of Biomedical and Health Sciences (Medical), Hiroshima University, Hiroshima, 734-8553, Japan
| | - Takaaki Sokabe
- Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8787, Japan.
- Thermal Biology Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan.
- Department of Physiological Sciences, SOKENDAI, Okazaki, Aichi, 444-8787, Japan.
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, 100-0004, Japan.
| | - Toru Miura
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, 658-8501, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8787, Japan
- Thermal Biology Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Department of Physiological Sciences, SOKENDAI, Okazaki, Aichi, 444-8787, Japan
| | - Akane Ohta
- Graduate school of Natural Science, Konan University, Kobe, Hyogo, 658-8501, Japan.
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, 658-8501, Japan.
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, 658-8501, Japan.
| | - Atsushi Kuhara
- Graduate school of Natural Science, Konan University, Kobe, Hyogo, 658-8501, Japan.
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, 658-8501, Japan.
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, 658-8501, Japan.
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, 100-0004, Japan.
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Wu N, Chen YA, Zhu Q, Son CH, Gu KZ, Zou CG, Wu QY, Ma YC. The EGL-30 pathway regulates experience-dependent aversive behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa. Biochem Biophys Res Commun 2023; 642:107-112. [PMID: 36566561 DOI: 10.1016/j.bbrc.2022.12.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Avoidance of harmful substances is survival strategy used cross invertebrates and vertebrates. For example, the nematode Caenorhabditis elegans evolves a sufficient avoidance response to pathogenic bacteria. Despite G protein has been found to exert neural plasticity for avoidance behaviours in C. elegans, the function of Gi/o and Gq subunit signalling in experience-dependent aversive behaviour remains unclear. In this study, we show that EGL-30/Gq coupled with EGL-8/UNC-13 regulates aversive behaviour of C. elegans to pathogenic bacterium Pseudomonas aeruginosa PA01 via acetylcholine and its receptor nAChR. Pyocyanin, a toxin secreted from P. aeruginosa, acts as a signal molecule to trigger aversive behaviour. ODR-3 and ODR-7 in AWA and AWC neurons function as upstream of EGL-30 to induce experience-dependent aversive behaviour to P. aeruginosa, respectively. These results suggested that a novel signalling pathway to regulate a behavioural response.
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Affiliation(s)
- Nan Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Yu-An Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qian Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cai-Hua Son
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Kun-Ze Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cheng-Gang Zou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qin-Yi Wu
- Yunnan Provincial Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Chinese Medicine, Kunming, 650500, Yunnan, China.
| | - Yi-Cheng Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China.
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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5
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Zhu A, Ji Z, Zhao J, Zhang W, Sun Y, Zhang T, Gao S, Li G, Wang Q. Effect of Euphorbia factor L1 on intestinal barrier impairment and defecation dysfunction in Caenorhabditis elegans. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 65:153102. [PMID: 31654989 DOI: 10.1016/j.phymed.2019.153102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/22/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Euphorbia factor L1 (EFL1) is a lathyrane-type diterpenoid from the medicinal herb Euphorbia lathyris L., and has been reported with intestinal toxicity, but the potential mechanisms remain unknown. PURPOSE The objective of this study was to investigate the intestinal toxicity of EFL1 and the underlying mechanisms using nematode Caenorhabditis elegans. METHODS C. elegans were exposed to 0-200 μM EFL1 for 72 h, then the survival rate, body length and body width, locomotion and chemoreception behavior, intestinal ROS and lipofuscin accumulation, intestinal permeability, and defecation rhythm were detected. The γ-aminobutyric acid(GABA) energic neurons AVL and DVB were shown via green fluorescent protein under a laser scanning confocal microscope. The structure of GABA transporter UNC-47 were predicted by homology modeling, and the interaction between EFL1 and UNC-47 was simulated by molecular docking. The mRNA expression of genes related to oxidative stress, intestinal permeability and defecation after EFL1 exposure were detected by RT-qPCR. RESULTS EFL1 did not induce lethality of nematodes. The general toxicity was characterized by abnormal growth, locomotion and chemoreception. The intestinal barrier was leaky, due to down-regulated cell junction and active cation transport. The mean defecation cycle length in nematodes was decreased, relating to disorder vesicular and ion transport, enhanced rhythm behavior and muscle contraction. The dysfunctional defecation also attributed to injured UNC-47 protein, as well as GABAergic neurons AVL and DVB. Excessive ROS and lipofuscin accumulation were observed in intestine, along with activation of antioxidant enzymes of SOD, COQ7 and CAT. CONCLUSION This study elucidated the EFL1-induced intestinal toxicity in nematodes, characterized as leaky intestinal barrier and accelerated defecation behavior. The underlying mechanisms were involved in oxidative stress, cell junctions, transportation, rhythm behavior, muscle contraction, and GABAergic neurons.
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Affiliation(s)
- An Zhu
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Zonghui Ji
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Jingwei Zhao
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Wenjing Zhang
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China; School of Public Health, Capital Medical University, Beijing 100069, China
| | - Yuqing Sun
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Tao Zhang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Shan Gao
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China
| | - Guojun Li
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China; School of Public Health, Capital Medical University, Beijing 100069, China.
| | - Qi Wang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Key Laboratory of State Administration of Traditional Chinese Medicine for Compatibility Toxicology, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China.
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6
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Liu P, Shao H, Ding X, Yang R, Rui Q, Wang D. Dysregulation of Neuronal Gαo Signaling by Graphene Oxide in Nematode Caenorhabditis elegans. Sci Rep 2019; 9:6026. [PMID: 30988375 PMCID: PMC6465305 DOI: 10.1038/s41598-019-42603-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 03/28/2019] [Indexed: 12/29/2022] Open
Abstract
Exposure to graphene oxide (GO) induced some dysregulated microRNAs (miRNAs), such as the increase in mir-247, in nematode Caenorhabditis elegans. We here further identified goa-1 encoding a Gαo and pkc-1 encoding a serine/threonine protein kinase as the targets of neuronal mir-247 in the regulation of GO toxicity. GO exposure increased the expressions of both GOA-1 and PKC-1. Mutation of goa-1 or pkc-1 induced a susceptibility to GO toxicity, and suppressed the resistance of mir-247 mutant to GO toxicity. GOA-1 and PKC-1 could also act in the neurons to regulate the GO toxicity, and neuronal overexpression of mir-247 could not affect the resistance of nematodes overexpressing neuronal goa-1 or pkc-1 lacking 3'-UTR to GO toxicity. In the neurons, GOA-1 acted upstream of diacylglycerol kinase/DGK-1 and PKC-1 to regulate the GO toxicity. Moreover, DGK-1 and GOA-1 functioned synergistically in the regulation of GO toxicity. Our results highlight the crucial role of neuronal Gαo signaling in response to GO in nematodes.
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Affiliation(s)
- Peidang Liu
- Medical School, Southeast University, Nanjing, 210009, China
| | - Huimin Shao
- Medical School, Southeast University, Nanjing, 210009, China
| | - Xuecheng Ding
- Medical School, Southeast University, Nanjing, 210009, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ruilong Yang
- Medical School, Southeast University, Nanjing, 210009, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qi Rui
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Dayong Wang
- Medical School, Southeast University, Nanjing, 210009, China.
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7
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Mirzakhalili E, Epureanu BI, Gourgou E. A mathematical and computational model of the calcium dynamics in Caenorhabditis elegans ASH sensory neuron. PLoS One 2018; 13:e0201302. [PMID: 30048509 PMCID: PMC6062085 DOI: 10.1371/journal.pone.0201302] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/28/2018] [Indexed: 12/31/2022] Open
Abstract
We propose a mathematical and computational model that captures the stimulus-generated Ca2+ transients in the C. elegans ASH sensory neuron. The rationale is to develop a tool that will enable a cross-talk between modeling and experiments, using modeling results to guide targeted experimental efforts. The model is built based on biophysical events and molecular cascades known to unfold as part of neurons' Ca2+ homeostasis mechanism, as well as on Ca2+ signaling events. The state of ion channels is described by their probability of being activated or inactivated, and the remaining molecular states are based on biochemically defined kinetic equations or known biochemical motifs. We estimate the parameters of the model using experimental data of hyperosmotic stimulus-evoked Ca2+ transients detected with a FRET sensor in young and aged worms, unstressed and exposed to oxidative stress. We use a hybrid optimization method composed of a multi-objective genetic algorithm and nonlinear least-squares to estimate the model parameters. We first obtain the model parameters for young unstressed worms. Next, we use these values of the parameters as a starting point to identify the model parameters for stressed and aged worms. We show that the model, in combination with experimental data, corroborates literature results. In addition, we demonstrate that our model can be used to predict ASH response to complex combinations of stimulation pulses. The proposed model includes for the first time the ASH Ca2+ dynamics observed during both "on" and "off" responses. This mathematical and computational effort is the first to propose a dynamic model of the Ca2+ transients' mechanism in C. elegans neurons, based on biochemical pathways of the cell's Ca2+ homeostasis machinery. We believe that the proposed model can be used to further elucidate the Ca2+ dynamics of a key C. elegans neuron, to guide future experiments on C. elegans neurobiology, and to pave the way for the development of more mathematical models for neuronal Ca2+ dynamics.
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Affiliation(s)
- Ehsan Mirzakhalili
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bogdan I. Epureanu
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Eleni Gourgou
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, Division of Geriatrics, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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8
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The NCA-1 and NCA-2 Ion Channels Function Downstream of G q and Rho To Regulate Locomotion in Caenorhabditis elegans. Genetics 2017; 206:265-282. [PMID: 28325749 DOI: 10.1534/genetics.116.198820] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/15/2017] [Indexed: 02/07/2023] Open
Abstract
The heterotrimeric G protein Gq positively regulates neuronal activity and synaptic transmission. Previously, the Rho guanine nucleotide exchange factor Trio was identified as a direct effector of Gq that acts in parallel to the canonical Gq effector phospholipase C. Here, we examine how Trio and Rho act to stimulate neuronal activity downstream of Gq in the nematode Caenorhabditis elegans Through two forward genetic screens, we identify the cation channels NCA-1 and NCA-2, orthologs of mammalian NALCN, as downstream targets of the Gq-Rho pathway. By performing genetic epistasis analysis using dominant activating mutations and recessive loss-of-function mutations in the members of this pathway, we show that NCA-1 and NCA-2 act downstream of Gq in a linear pathway. Through cell-specific rescue experiments, we show that function of these channels in head acetylcholine neurons is sufficient for normal locomotion in C. elegans Our results suggest that NCA-1 and NCA-2 are physiologically relevant targets of neuronal Gq-Rho signaling in C. elegans.
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Soares FA, Fagundez DA, Avila DS. Neurodegeneration Induced by Metals in Caenorhabditis elegans. ADVANCES IN NEUROBIOLOGY 2017; 18:355-383. [PMID: 28889277 DOI: 10.1007/978-3-319-60189-2_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metals are a component of a variety of ecosystems and organisms. They can generally be divided into essential and nonessential metals. The essential metals are involved in physiological processes once the deficiency of these metals has been associated with diseases. Although iron, manganese, copper, and zinc are important for life, it has been evidenced that they are also involved in neuronal damage in many neurodegenerative disorders. Nonessential metals, which are metals without physiological functions, are present in trace or higher levels in living organisms. Occupational, environmental, or deliberate exposures to lead, mercury, aluminum, and cadmium are clearly correlated with the increase of toxicity and varied kinds of pathological situations. Actually, the field of neurotoxicology needs to satisfy two opposing demands: the testing of a growing list of chemicals and resource limitations and ethical concerns associated with testing using traditional mammalian species. Toxicological assays using alternative animal models may relieve some of this pressure by allowing testing of more compounds while reducing expenses and using fewer mammals. The nervous system is by far the more complex system in C. elegans. Almost a third of their cells are neurons (302 neurons versus 959 cells in adult hermaphrodite). It initially underwent extensive development as a model organism in order to study the nervous system, and its neuronal lineage and the complete wiring diagram of its nervous system are stereotyped and fully described. The neurotransmission systems are phylogenetically conserved from nematodes to vertebrates, which allows for findings from C. elegans to be extrapolated and further confirmed in vertebrate systems. Different strains of C. elegans offer a new perspective on neurodegenerative processes. Some genes have been found to be related to neurodegeneration induced by metals. Studying these interactions may be an effective tool to slow neuronal loss and deterioration.
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Affiliation(s)
- Felix Antunes Soares
- Departamento de Bioquimica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, 97105-900, Brazil.
| | | | - Daiana Silva Avila
- Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul, 97508-000, Brazil.
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Nagy S, Goessling M, Amit Y, Biron D. A Generative Statistical Algorithm for Automatic Detection of Complex Postures. PLoS Comput Biol 2015; 11:e1004517. [PMID: 26439258 PMCID: PMC4595081 DOI: 10.1371/journal.pcbi.1004517] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 08/25/2015] [Indexed: 02/06/2023] Open
Abstract
This paper presents a method for automated detection of complex (non-self-avoiding) postures of the nematode Caenorhabditis elegans and its application to analyses of locomotion defects. Our approach is based on progressively detailed statistical models that enable detection of the head and the body even in cases of severe coilers, where data from traditional trackers is limited. We restrict the input available to the algorithm to a single digitized frame, such that manual initialization is not required and the detection problem becomes embarrassingly parallel. Consequently, the proposed algorithm does not propagate detection errors and naturally integrates in a "big data" workflow used for large-scale analyses. Using this framework, we analyzed the dynamics of postures and locomotion of wild-type animals and mutants that exhibit severe coiling phenotypes. Our approach can readily be extended to additional automated tracking tasks such as tracking pairs of animals (e.g., for mating assays) or different species.
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Affiliation(s)
- Stanislav Nagy
- The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, United States of America
| | - Marc Goessling
- Department of Statistics, The University of Chicago, Chicago, Illinois, United States of America
| | - Yali Amit
- Department of Statistics, The University of Chicago, Chicago, Illinois, United States of America
- Department of Computer Science, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (YA); (DB)
| | - David Biron
- The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, United States of America
- Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (YA); (DB)
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11
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Wang D, Yu Y, Li Y, Wang Y, Wang D. Dopamine receptors antagonistically regulate behavioral choice between conflicting alternatives in C. elegans. PLoS One 2014; 9:e115985. [PMID: 25536037 PMCID: PMC4275273 DOI: 10.1371/journal.pone.0115985] [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: 08/07/2014] [Accepted: 12/03/2014] [Indexed: 11/18/2022] Open
Abstract
Caenorhabditis elegans is a useful model to study the neuronal or molecular basis for behavioral choice, a specific form of decision-making. Although it has been implied that both D1-like and D2-like dopamine receptors may contribute to the control of decision-making in mammals, the genetic interactions between D1-like and D2-like dopamine receptors in regulating decision-making are still largely unclear. In the present study, we investigated the molecular control of behavioral choice between conflicting alternatives (diacetyl and Cu2+) by D1-like and D2-like dopamine receptors and their possible genetic interactions with C. elegans as the assay system. In the behavioral choice assay system, mutation of dop-1 gene encoding D1-like dopamine receptor resulted in the enhanced tendency to cross the Cu2+ barrier compared with wild-type. In contrast, mutations of dop-2 or dop-3 gene encoding D2-like dopamine receptor caused the weak tendency to cross the Cu2+ barrier compared with wild-type. During the control of behavioral choice, DOP-3 antagonistically regulated the function of DOP-1. The behavioral choice phenotype of dop-2; dop-1dop-3 triple mutant further confirmed the possible antagonistic function of D2-like dopamine receptor on D1-like dopamine receptor in regulating behavioral choice. The genetic assays further demonstrate that DOP-3 might act through Gαo signaling pathway encoded by GOA-1 and EGL-10, and DOP-1 might act through Gαq signaling pathway encoded by EGL-30 and EAT-16 to regulate the behavioral choice. DOP-1 might function in cholinergic neurons to regulate the behavioral choice, whereas DOP-3 might function in GABAergic neurons, RIC, and SIA neurons to regulate the behavioral choice. In this study, we provide the genetic evidence to indicate the antagonistic relationship between D1-like dopamine receptor and D2-like dopamine receptor in regulating the decision-making of animals. Our data will be useful for understanding the complex functions of dopamine receptors in regulating decision-making in animals.
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Affiliation(s)
- Daoyong Wang
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, 210009, China
| | - Yonglin Yu
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, 210009, China
| | - Yinxia Li
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, 210009, China
| | - Yang Wang
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, 210009, China
| | - Dayong Wang
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School of Southeast University, Nanjing, 210009, China
- * E-mail:
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12
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Zahratka JA, Williams PDE, Summers PJ, Komuniecki RW, Bamber BA. Serotonin differentially modulates Ca2+ transients and depolarization in a C. elegans nociceptor. J Neurophysiol 2014; 113:1041-50. [PMID: 25411461 DOI: 10.1152/jn.00665.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Monoamines and neuropeptides modulate neuronal excitability and synaptic strengths, shaping circuit activity to optimize behavioral output. In C. elegans, a pair of bipolar polymodal nociceptors, the ASHs, sense 1-octanol to initiate escape responses. In the present study, 1-octanol stimulated large increases in ASH Ca(2+), mediated by L-type voltage-gated Ca(2+) channels (VGCCs) in the cell soma and L-plus P/Q-type VGCCs in the axon, which were further amplified by Ca(2+) released from intracellular stores. Importantly, 1-octanol-dependent aversive responses were not inhibited by reducing ASH L-VGCC activity genetically or pharmacologically. Serotonin, an enhancer of 1-octanol avoidance, potentiated 1-octanol-dependent ASH depolarization measured electrophysiologically, but surprisingly, decreased the ASH somal Ca(2+) transients. These results suggest that ASH somal Ca(2+) transient amplitudes may not always be predictive of neuronal depolarization and synaptic output. Therefore, although increases in steady-state Ca(2+) can reliably indicate when neurons become active, quantitative relationships between Ca(2+) transient amplitudes and neuronal activity may not be as straightforward as previously anticipated.
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Affiliation(s)
- Jeffrey A Zahratka
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | - Paul D E Williams
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | - Philip J Summers
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | | | - Bruce A Bamber
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
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13
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Sassa T, Maruyama IN. A G-protein α subunit, GOA-1, plays a role in C. elegans avoidance behavior of strongly alkaline pH. Commun Integr Biol 2013; 6:e26668. [PMID: 24563709 PMCID: PMC3917944 DOI: 10.4161/cib.26668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 11/19/2022] Open
Abstract
The ability of animals to avoid strongly alkaline pH is critical for survival. However, the means by which they sense high pH has not been determined. We have previously found that the nematode Caenorhabditis elegans (C. elegans) avoids environmental pH above 10.5. Detection involves ASH nociceptive neurons as the major sensors. Upon stimulation, transient receptor potential vanilloid-type (TRPV) ion channels encoded by osm-9 and ocr-2 play an essential role in Ca2+ entry into ASH. Here we report that C. elegans mutants deficient in a G-protein α subunit, GOA-1, failed to avoid strongly alkaline pH with normal Ca2+ influx into ASH. These results suggest that GOA-1 regulates signal transmission downstream of Ca2+ influx through OSM-9/OCR-2 TRPV channels in ASH.
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Affiliation(s)
- Toshihiro Sassa
- Information Processing Biology Unit; Okinawa Institute of Science and Technology Graduate University; Okinawa, Japan
| | - Ichi N Maruyama
- Information Processing Biology Unit; Okinawa Institute of Science and Technology Graduate University; Okinawa, Japan
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14
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Krzyzanowski MC, Brueggemann C, Ezak MJ, Wood JF, Michaels KL, Jackson CA, Juang BT, Collins KD, Yu MC, L'Etoile ND, Ferkey DM. The C. elegans cGMP-dependent protein kinase EGL-4 regulates nociceptive behavioral sensitivity. PLoS Genet 2013; 9:e1003619. [PMID: 23874221 PMCID: PMC3708839 DOI: 10.1371/journal.pgen.1003619] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 05/23/2013] [Indexed: 11/25/2022] Open
Abstract
Signaling levels within sensory neurons must be tightly regulated to allow cells to integrate information from multiple signaling inputs and to respond to new stimuli. Herein we report a new role for the cGMP-dependent protein kinase EGL-4 in the negative regulation of G protein-coupled nociceptive chemosensory signaling. C. elegans lacking EGL-4 function are hypersensitive in their behavioral response to low concentrations of the bitter tastant quinine and exhibit an elevated calcium flux in the ASH sensory neurons in response to quinine. We provide the first direct evidence for cGMP/PKG function in ASH and propose that ODR-1, GCY-27, GCY-33 and GCY-34 act in a non-cell-autonomous manner to provide cGMP for EGL-4 function in ASH. Our data suggest that activated EGL-4 dampens quinine sensitivity via phosphorylation and activation of the regulator of G protein signaling (RGS) proteins RGS-2 and RGS-3, which in turn downregulate Gα signaling and behavioral sensitivity.
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Affiliation(s)
- Michelle C. Krzyzanowski
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, California, United States of America
| | - Meredith J. Ezak
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Jordan F. Wood
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Kerry L. Michaels
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Christopher A. Jackson
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Bi-Tzen Juang
- Department of Cell and Tissue Biology, University of California, San Francisco, California, United States of America
| | - Kimberly D. Collins
- Department of Cell and Tissue Biology, University of California, San Francisco, California, United States of America
| | - Michael C. Yu
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Noelle D. L'Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, California, United States of America
| | - Denise M. Ferkey
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
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15
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Smith MA, Zhang Y, Polli JR, Wu H, Zhang B, Xiao P, Farwell MA, Pan X. Impacts of chronic low-level nicotine exposure on Caenorhabditis elegans reproduction: identification of novel gene targets. Reprod Toxicol 2013; 40:69-75. [PMID: 23735997 DOI: 10.1016/j.reprotox.2013.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/25/2013] [Accepted: 05/24/2013] [Indexed: 12/17/2022]
Abstract
Effects and mechanisms of chronic exposure to low levels of nicotine is an area fundamentally important however less investigated. We employed the model organism Caenorhabditis elegans to investigate potential impacts of chronic (24h) and low nicotine exposure (6.17-194.5 μM) on stimulus-response, reproduction, and gene expressions. Nicotine significantly affects the organism's response to touch stimulus (p=0.031), which follows a dose-dependent pattern. Chronic nicotine exposure promotes early egg-laying events and slightly increased egg productions during the first 72 h of adulthood. The expressions of 10 (egl-10, egl-44, hlh-14, ric-3, unc-103, unc-50, unc-68, sod-1, oxi-1, and old-1) out of 18 selected genes were affected significantly. Other tested genes were cat-4, egl-19, egl-47, egl-5, lin-39, unc-43, pink-1, and age-1. Changes in gene expression were more evident at low dosages than at relatively high levels. Genes implicated in reproduction, cholinergic signaling, and stress response were regulated by nicotine, suggesting widespread physiological impacts of nicotine.
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Affiliation(s)
- Michael A Smith
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
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16
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McVeigh P, Atkinson L, Marks NJ, Mousley A, Dalzell JJ, Sluder A, Hammerland L, Maule AG. Parasite neuropeptide biology: Seeding rational drug target selection? Int J Parasitol Drugs Drug Resist 2012; 2:76-91. [PMID: 24533265 PMCID: PMC3862435 DOI: 10.1016/j.ijpddr.2011.10.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/25/2011] [Accepted: 10/28/2011] [Indexed: 01/16/2023]
Abstract
The rationale for identifying drug targets within helminth neuromuscular signalling systems is based on the premise that adequate nerve and muscle function is essential for many of the key behavioural determinants of helminth parasitism, including sensory perception/host location, invasion, locomotion/orientation, attachment, feeding and reproduction. This premise is validated by the tendency of current anthelmintics to act on classical neurotransmitter-gated ion channels present on helminth nerve and/or muscle, yielding therapeutic endpoints associated with paralysis and/or death. Supplementary to classical neurotransmitters, helminth nervous systems are peptide-rich and encompass associated biosynthetic and signal transduction components - putative drug targets that remain to be exploited by anthelmintic chemotherapy. At this time, no neuropeptide system-targeting lead compounds have been reported, and given that our basic knowledge of neuropeptide biology in parasitic helminths remains inadequate, the short-term prospects for such drugs remain poor. Here, we review current knowledge of neuropeptide signalling in Nematoda and Platyhelminthes, and highlight a suite of 19 protein families that yield deleterious phenotypes in helminth reverse genetics screens. We suggest that orthologues of some of these peptidergic signalling components represent appealing therapeutic targets in parasitic helminths.
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Affiliation(s)
- Paul McVeigh
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Louise Atkinson
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Nikki J. Marks
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Angela Mousley
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Johnathan J. Dalzell
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Ann Sluder
- Scynexis Inc., P.O. Box 12878, Research Triangle Park, NC 27709-2878, USA
| | | | - Aaron G. Maule
- Molecular Biosciences–Parasitology, Institute of Agri-Food and Land Use, School of Biological Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
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17
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Wood JF, Wang J, Benovic JL, Ferkey DM. Structural domains required for Caenorhabditis elegans G protein-coupled receptor kinase 2 (GRK-2) function in vivo. J Biol Chem 2012; 287:12634-44. [PMID: 22375004 PMCID: PMC3339999 DOI: 10.1074/jbc.m111.336818] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/13/2012] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptor kinases (GRKs) are key regulators of signal transduction that specifically phosphorylate activated G protein-coupled receptors (GPCRs) to terminate signaling. Biochemical and crystallographic studies have provided great insight into mammalian GRK2/3 interactions and structure. However, despite extensive in vitro characterization, little is known about the in vivo contribution of these described GRK structural domains and interactions to proper GRK function in signal regulation. We took advantage of the disrupted chemosensory behavior characteristic of Caenorhabditis elegans grk-2 mutants to discern the interactions required for proper in vivo Ce-GRK-2 function. Informed by mammalian crystallographic and biochemical data, we introduced amino acid substitutions into the Ce-grk-2 coding sequence that are predicted to selectively disrupt GPCR phosphorylation, Gα(q/11) binding, Gβγ binding, or phospholipid binding. Changing the most amino-terminal residues, which have been shown in mammalian systems to be required specifically for GPCR phosphorylation but not phosphorylation of alternative substrates or recruitment to activated GPCRs, eliminated the ability of Ce-GRK-2 to restore chemosensory signaling. Disrupting interaction between the predicted Ce-GRK-2 amino-terminal α-helix and kinase domain, posited to stabilize GRKs in their active ATP- and GPCR-bound conformation, also eliminated Ce-GRK-2 chemosensory function. Finally, although changing residues within the RH domain, predicted to disrupt interaction with Gα(q/11), did not affect Ce-GRK-2 chemosensory function, disruption of the predicted PH domain-mediated interactions with Gβγ and phospholipids revealed that both contribute to Ce-GRK-2 function in vivo. Combined, we have demonstrated functional roles for broadly conserved GRK2/3 structural domains in the in vivo regulation of organismal behavior.
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Affiliation(s)
- Jordan F. Wood
- From the Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260 and
| | - Jianjun Wang
- the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Jeffrey L. Benovic
- the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Denise M. Ferkey
- From the Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260 and
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18
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AGS-3 alters Caenorhabditis elegans behavior after food deprivation via RIC-8 activation of the neural G protein G αo. J Neurosci 2011; 31:11553-62. [PMID: 21832186 DOI: 10.1523/jneurosci.2072-11.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Proteins containing the G protein regulator (GPR) domain bind the major neural G protein Gα(o) in vitro. However, the biological functions of GPR proteins in neurons remain undefined, and based on the in vitro activities of GPR proteins it is unclear whether these proteins activate or inhibit G protein signaling in vivo. We found that the conserved GPR domain protein AGS-3 activates Gα(o) signaling in vivo to allow Caenorhabditis elegans to alter several behaviors after food deprivation, apparently so that the animals can more effectively seek food. AGS-3 undergoes a progressive change in its biochemical fractionation upon food deprivation, suggesting that effects of food deprivation are mediated by modifying this protein. We analyzed one C. elegans food-regulated behavior in depth; AGS-3 activates Gα(o) in the ASH chemosensory neurons to allow food-deprived animals to delay response to the aversive stimulus octanol. Genetic epistasis experiments show the following: (1) AGS-3 and the guanine nucleotide exchange factor RIC-8 act in ASH in a mutually dependent fashion to activate Gα(o); (2) this activation requires interaction of the GPR domains of AGS-3 with Gα(o); and (3) Gα(o)-GTP is ultimately the signaling molecule that acts in ASH to delay octanol response. These results identify a biological role for AGS-3 in response to food deprivation and indicate the mechanism for its activation of Gα(o) signaling in vivo.
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19
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Harris G, Korchnak A, Summers P, Hapiak V, Law WJ, Stein AM, Komuniecki P, Komuniecki R. Dissecting the serotonergic food signal stimulating sensory-mediated aversive behavior in C. elegans. PLoS One 2011; 6:e21897. [PMID: 21814562 PMCID: PMC3140990 DOI: 10.1371/journal.pone.0021897] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 06/08/2011] [Indexed: 11/18/2022] Open
Abstract
Nutritional state often modulates olfaction and in Caenorhabditis elegans food stimulates aversive responses mediated by the nociceptive ASH sensory neurons. In the present study, we have characterized the role of key serotonergic neurons that differentially modulate aversive behavior in response to changing nutritional status. The serotonergic NSM and ADF neurons play antagonistic roles in food stimulation. NSM 5-HT activates SER-5 on the ASHs and SER-1 on the RIA interneurons and stimulates aversive responses, suggesting that food-dependent serotonergic stimulation involves local changes in 5-HT levels mediated by extrasynaptic 5-HT receptors. In contrast, ADF 5-HT activates SER-1 on the octopaminergic RIC interneurons to inhibit food-stimulation, suggesting neuron-specific stimulatory and inhibitory roles for SER-1 signaling. Both the NSMs and ADFs express INS-1, an insulin-like peptide, that appears to cell autonomously inhibit serotonergic signaling. Food also modulates directional decisions after reversal is complete, through the same serotonergic neurons and receptors involved in the initiation of reversal, and the decision to continue forward or change direction after reversal is dictated entirely by nutritional state. These results highlight the complexity of the "food signal" and serotonergic signaling in the modulation of sensory-mediated aversive behaviors.
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Affiliation(s)
- Gareth Harris
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Amanda Korchnak
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Philip Summers
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Vera Hapiak
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Wen Jing Law
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Andrew M. Stein
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Patricia Komuniecki
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Richard Komuniecki
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
- * E-mail:
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