1
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Graziano B, Wang L, White OR, Kaplan DH, Fernandez-Abascal J, Bianchi L. Glial KCNQ K + channels control neuronal output by regulating GABA release from glia in C. elegans. Neuron 2024; 112:1832-1847.e7. [PMID: 38460523 PMCID: PMC11156561 DOI: 10.1016/j.neuron.2024.02.013] [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: 10/04/2023] [Revised: 01/22/2024] [Accepted: 02/16/2024] [Indexed: 03/11/2024]
Abstract
KCNQs are voltage-gated K+ channels that control neuronal excitability and are mutated in epilepsy and autism spectrum disorder (ASD). KCNQs have been extensively studied in neurons, but their function in glia is unknown. Using voltage, calcium, and GABA imaging, optogenetics, and behavioral assays, we show here for the first time in Caenorhabditis elegans (C. elegans) that glial KCNQ channels control neuronal excitability by mediating GABA release from glia via regulation of the function of L-type voltage-gated Ca2+ channels. Further, we show that human KCNQ channels have the same role when expressed in nematode glia, underscoring conservation of function across species. Finally, we show that pathogenic loss-of-function and gain-of-function human KCNQ2 mutations alter glia-to-neuron GABA signaling in distinct ways and that the KCNQ channel opener retigabine exerts rescuing effects. This work identifies glial KCNQ channels as key regulators of neuronal excitability via control of GABA release from glia.
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Affiliation(s)
- Bianca Graziano
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Lei Wang
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Olivia R White
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Daryn H Kaplan
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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2
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Kim AT, Li S, Kim Y, You YJ, Park Y. Food preference-based screening method for identification of effectors of substance use disorders using Caenorhabditis elegans. Life Sci 2024; 345:122580. [PMID: 38514005 DOI: 10.1016/j.lfs.2024.122580] [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: 12/18/2023] [Revised: 02/26/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
Substance use disorder (SUD) affects over 48 million Americans aged 12 and over. Thus, identifying novel chemicals contributing to SUD will be critical for developing efficient prevention and mitigation strategies. Considering the complexity of the actions and effects of these substances on human behavior, a high-throughput platform using a living organism is ideal. We developed a quick and easy screening assay using Caenorhabditis elegans. C. elegans prefers high-quality food (Escherichia coli HB101) over low-quality food (Bacillus megaterium), with a food preference index of approximately 0.2, defined as the difference in the number of worms at E. coli HB101 and B. megaterium over the total worm number. The food preference index was significantly increased by loperamide, a μ-opioid receptor (MOPR) agonist, and decreased by naloxone, a MOPR antagonist. These changes depended on npr-17, a C. elegans homolog of opioid receptors. In addition, the food preference index was significantly increased by arachidonyl-2'-chloroethylamide, a cannabinoid 1 receptor (CB1R) agonist, and decreased by rimonabant, a CB1R inverse agonist. These changes depended on npr-19, a homolog of CB1R. These results suggest that the conserved opioid and endocannabinoid systems modulate the food preference behaviors of C. elegans. Finally, the humanoid C. elegans strains where npr-17 was replaced with human MOPR and where npr-19 was replaced with human CB1R phenocopied the changes in food preference by the drug treatment. Together, the current results show that this method can be used to rapidly screen the potential effectors of MOPR and CB1R to yield results highly translatable to humans.
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Affiliation(s)
- Aaron Taehwan Kim
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Sida Li
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Yoo Kim
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Young-Jai You
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yeonhwa Park
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA.
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3
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Choi U, Hu M, Zhang Q, Sieburth D. The head mesodermal cell couples FMRFamide neuropeptide signaling with rhythmic muscle contraction in C. elegans. Nat Commun 2023; 14:4218. [PMID: 37452027 PMCID: PMC10349088 DOI: 10.1038/s41467-023-39955-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
FMRFamides are evolutionarily conserved neuropeptides that play critical roles in behavior, energy balance, and reproduction. Here, we show that FMRFamide signaling from the nervous system is critical for the rhythmic activation of a single cell of previously unknown function, the head mesodermal cell (hmc) in C. elegans. Behavioral, calcium imaging, and genetic studies reveal that release of the FLP-22 neuropeptide from the AVL neuron in response to pacemaker signaling activates hmc every 50 s through an frpr-17 G protein-coupled receptor (GPCR) and a protein kinase A signaling cascade in hmc. hmc activation results in muscle contraction through coupling by gap junctions composed of UNC-9/Innexin. hmc activation is inhibited by the neuronal release of a second FMRFamide-like neuropeptide, FLP-9, which functions through its GPCR, frpr-21, in hmc. This study reveals a function for two opposing FMRFamide signaling pathways in controlling the rhythmic activation of a target cell through volume transmission.
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Affiliation(s)
- Ukjin Choi
- DSR graduate program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Mingxi Hu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Qixin Zhang
- MPHY program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
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4
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Olson AC, Butt AM, Christie NTM, Shelar A, Koelle MR. Multiple Subthreshold GPCR Signals Combined by the G-Proteins Gα q and Gα s Activate the Caenorhabditis elegans Egg-Laying Muscles. J Neurosci 2023; 43:3789-3806. [PMID: 37055179 PMCID: PMC10219013 DOI: 10.1523/jneurosci.2301-22.2023] [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: 12/14/2022] [Revised: 03/21/2023] [Accepted: 04/07/2023] [Indexed: 04/15/2023] Open
Abstract
Individual neurons or muscle cells express many G-protein-coupled receptors (GPCRs) for neurotransmitters and neuropeptides, yet it remains unclear how cells integrate multiple GPCR signals that all must activate the same few G-proteins. We analyzed this issue in the Caenorhabditis elegans egg-laying system, where multiple GPCRs on muscle cells promote contraction and egg laying. We genetically manipulated individual GPCRs and G-proteins specifically in these muscle cells within intact animals and then measured egg laying and muscle calcium activity. Two serotonin GPCRs on the muscle cells, Gαq-coupled SER-1 and Gαs-coupled SER-7, together promote egg laying in response to serotonin. We found that signals produced by either SER-1/Gαq or SER-7/Gαs alone have little effect, but these two subthreshold signals combine to activate egg laying. We then transgenically expressed natural or designer GPCRs in the muscle cells and found that their subthreshold signals can also combine to induce muscle activity. However, artificially inducing strong signaling through just one of these GPCRs can be sufficient to induce egg laying. Knocking down Gαq and Gαs in the egg-laying muscle cells induced egg-laying defects that were stronger than those of a SER-1/SER-7 double knockout, indicating that additional endogenous GPCRs also activate the muscle cells. These results show that in the egg-laying muscles multiple GPCRs for serotonin and other signals each produce weak effects that individually do not result in strong behavioral outcomes. However, they combine to produce sufficient levels of Gαq and Gαs signaling to promote muscle activity and egg laying.SIGNIFICANCE STATEMENT How can neurons and other cells gather multiple independent pieces of information from the soup of chemical signals in their environment and compute an appropriate response? Most cells express >20 GPCRs that each receive one signal and transmit that information through three main types of G-proteins. We analyzed how this machinery generates responses by studying the egg-laying system of C. elegans, where serotonin and multiple other signals act through GPCRs on the egg-laying muscles to promote muscle activity and egg laying. We found that individual GPCRs within an intact animal each generate effects too weak to activate egg laying. However, combined signaling from multiple GPCR types reaches a threshold capable of activating the muscle cells.
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Affiliation(s)
- Andrew C Olson
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Allison M Butt
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Nakeirah T M Christie
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Ashish Shelar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Michael R Koelle
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
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5
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Dudkevich R, Koh JH, Beaudoin-Chabot C, Celik C, Lebenthal-Loinger I, Karako-Lampert S, Ahmad-Albukhari S, Thibault G, Henis-Korenblit S. Neuronal IRE-1 coordinates an organism-wide cold stress response by regulating fat metabolism. Cell Rep 2022; 41:111739. [PMID: 36450261 DOI: 10.1016/j.celrep.2022.111739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 10/07/2022] [Accepted: 11/07/2022] [Indexed: 11/30/2022] Open
Abstract
Cold affects many aspects of biology, medicine, agriculture, and industry. Here, we identify a conserved endoplasmic reticulum (ER) stress response, distinct from the canonical unfolded protein response, that maintains lipid homeostasis during extreme cold. We establish that the ER stress sensor IRE-1 is critical for resistance to extreme cold and activated by cold temperature. Specifically, neuronal IRE-1 signals through JNK-1 and neuropeptide signaling to regulate lipid composition within the animal. This cold-response pathway can be bypassed by dietary supplementation with unsaturated fatty acids. Altogether, our findings define an ER-centric conserved organism-wide cold stress response, consisting of molecular neuronal sensors, effectors, and signaling moieties, which control adaptation to cold conditions in the organism. Better understanding of the molecular basis of this stress response is crucial for the optimal use of cold conditions on live organisms and manipulation of lipid saturation homeostasis, which is perturbed in human pathologies.
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Affiliation(s)
- Reut Dudkevich
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Jhee Hong Koh
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | | | - Cenk Celik
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | | | - Sarit Karako-Lampert
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Syed Ahmad-Albukhari
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore; Institute of Molecular and Cell Biology, A(∗)STAR, Singapore 138673, Singapore
| | - Sivan Henis-Korenblit
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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6
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Positive interaction between ASH and ASK sensory neurons accelerates nociception and inhibits behavioral adaptation. iScience 2022; 25:105287. [PMID: 36304123 PMCID: PMC9593764 DOI: 10.1016/j.isci.2022.105287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/22/2022] [Accepted: 10/04/2022] [Indexed: 11/23/2022] Open
Abstract
Central and peripheral sensory neurons tightly regulate nociception and avoidance behavior. The peripheral modulation of nociception provides more veridical and instantaneous information for animals to achieve rapid, more fine-tuned and concentrated behavioral responses. In this study, we find that positive interaction between ASH and ASK sensory neurons is essential for the fast-rising phase of ASH Ca2+ responses to noxious copper ions and inhibits the adaption of avoiding Cu2+. We reveal the underlying neuronal circuit mechanism. ASK accelerates the ASH Ca2+ responses by transferring cGMP through gap junctions. ASH excites ASK via a disinhibitory neuronal circuit composed of ASH, AIA, and ASK. Avoidance adaptation depends on the slope rate of the rising phase of ASH Ca2+ responses. Thus, in addition to amplitude, sensory kinetics is significant for sensations and behaviors, especially for sensory and behavioral adaptations.
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7
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Debnath A, Williams PDE, Bamber BA. Reduced Ca2+ transient amplitudes may signify increased or decreased depolarization depending on the neuromodulatory signaling pathway. Front Neurosci 2022; 16:931328. [PMID: 35937887 PMCID: PMC9354622 DOI: 10.3389/fnins.2022.931328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Neuromodulators regulate neuronal excitability and bias neural circuit outputs. Optical recording of neuronal Ca2+ transients is a powerful approach to study the impact of neuromodulators on neural circuit dynamics. We are investigating the polymodal nociceptor ASH in Caenorhabditis elegans to better understand the relationship between neuronal excitability and optically recorded Ca2+ transients. ASHs depolarize in response to the aversive olfactory stimulus 1-octanol (1-oct) with a concomitant rise in somal Ca2+, stimulating an aversive locomotory response. Serotonin (5-HT) potentiates 1-oct avoidance through Gαq signaling, which inhibits L-type voltage-gated Ca2+ channels in ASH. Although Ca2+ signals in the ASH soma decrease, depolarization amplitudes increase because Ca2+ mediates inhibitory feedback control of membrane potential in this context. Here, we investigate octopamine (OA) signaling in ASH to assess whether this negative correlation between somal Ca2+ and depolarization amplitudes is a general phenomenon, or characteristic of certain neuromodulatory pathways. Like 5-HT, OA reduces somal Ca2+ transient amplitudes in ASH neurons. However, OA antagonizes 5-HT modulation of 1-oct avoidance behavior, suggesting that OA may signal through a different pathway. We further show that the pathway for OA diminution of ASH somal Ca2+ consists of the OCTR-1 receptor, the Go heterotrimeric G-protein, and the G-protein activated inwardly rectifying channels IRK-2 and IRK-3, and this pathway reduces depolarization amplitudes in parallel with somal Ca2+ transient amplitudes. Therefore, even within a single neuron, somal Ca2+ signal reduction may indicate either increased or decreased depolarization amplitude, depending on which neuromodulatory signaling pathways are activated, underscoring the need for careful interpretation of Ca2+ imaging data in neuromodulatory studies.
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Affiliation(s)
- Arunima Debnath
- Department of Biological Sciences, The University of Toledo, Toledo, OH, United States
| | - Paul D. E. Williams
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Bruce A. Bamber
- Department of Biological Sciences, The University of Toledo, Toledo, OH, United States
- *Correspondence: Bruce A. Bamber,
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8
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Fernandez-Abascal J, Johnson CK, Graziano B, Wang L, Encalada N, Bianchi L. A glial ClC Cl - channel mediates nose touch responses in C. elegans. Neuron 2022; 110:470-485.e7. [PMID: 34861150 PMCID: PMC8813913 DOI: 10.1016/j.neuron.2021.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/28/2021] [Accepted: 11/09/2021] [Indexed: 02/04/2023]
Abstract
In touch receptors, glia and accessory cells play a key role in mechanosensation. However, the mechanisms underlying such regulation are poorly understood. We show, for the first time, that the chloride channel CLH-1 is needed in glia of C. elegans nose touch receptors for touch responses and for regulation of excitability. Using in vivo Ca2+ and Cl- imaging, behavioral assays, and combined genetic and pharmacological manipulations, we show that CLH-1 mediates Cl- flux needed for glial GABA inhibition of ASH sensory neuron function and for regulation of cyclic AMP levels in ASH neurons. Finally, we show that the rat ClC-2 channel rescues the clh-1 nose-touch-insensitive phenotype, underscoring conservation of function across species. Our work identifies a glial Cl- channel as a novel regulator of touch sensitivity. We propose that glial CLH-1 regulates the interplay between Ca2+ and cAMP signaling in ASH neurons to control the sensitivity of the worm's nose touch receptors.
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9
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Ide S, Kunitomo H, Iino Y, Ikeda K. Caenorhabditis Elegans Exhibits Morphine Addiction-like Behavior via the Opioid-like Receptor NPR-17. Front Pharmacol 2022; 12:802701. [PMID: 35046825 PMCID: PMC8762297 DOI: 10.3389/fphar.2021.802701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/09/2021] [Indexed: 11/14/2022] Open
Abstract
Addiction has become a profound societal problem worldwide, and few effective treatments are available. The nematode Caenorhabditis elegans (C. elegans) is an excellent invertebrate model to study neurobiological disease states. C. elegans reportedly developed a preference for cues that had previously been paired with addictive drugs, similar to place conditioning findings in rodents. Moreover, several recent studies discovered and reported the existence of an opioid-like system in C. elegans. Still unclear, however, is whether C. elegans exhibits addictive-like behaviors for opioids, such as morphine. In the present study, we found that C. elegans exhibited dose-dependent preference for morphine using the conditioned chemosensory-cue preference (CCP) test. This preference was blocked by co-treatment with the opioid receptor antagonist naloxone. C. elegans also exhibited aversion to naloxone-precipitated withdrawal from chronic morphine exposure. The expression of morphine-induced CCP and morphine withdrawal were abolished in worms that lacked the opioid-like receptor NPR-17. Dopamine-deficient mutant (cat-2 (e1112)) worms also did not exhibit morphine-induced CCP. These results indicate that the addictive function of the opioid system exists in C. elegans, which may serve as a useful model of opioid addiction.
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Affiliation(s)
- Soichiro Ide
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hirofumi Kunitomo
- Department of Biological Sciences, Faculty of Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Faculty of Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Kazutaka Ikeda
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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10
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Marques F, Falquet L, Vandewyer E, Beets I, Glauser DA. Signaling via the FLP-14/FRPR-19 neuropeptide pathway sustains nociceptive response to repeated noxious stimuli in C. elegans. PLoS Genet 2021; 17:e1009880. [PMID: 34748554 PMCID: PMC8601619 DOI: 10.1371/journal.pgen.1009880] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/18/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022] Open
Abstract
In order to thrive in constantly changing environments, animals must adaptively respond to threatening events. Noxious stimuli are not only processed according to their absolute intensity, but also to their context. Adaptation processes can cause animals to habituate at different rates and degrees in response to permanent or repeated stimuli. Here, we used a forward genetic approach in Caenorhabditis elegans to identify a neuropeptidergic pathway, essential to prevent fast habituation and maintain robust withdrawal responses to repeated noxious stimuli. This pathway involves the FRPR-19A and FRPR-19B G-protein coupled receptor isoforms produced from the frpr-19 gene by alternative splicing. Loss or overexpression of each or both isoforms can impair withdrawal responses caused by the optogenetic activation of the polymodal FLP nociceptor neuron. Furthermore, we identified FLP-8 and FLP-14 as FRPR-19 ligands in vitro. flp-14, but not flp-8, was essential to promote withdrawal response and is part of the same genetic pathway as frpr-19 in vivo. Expression and cell-specific rescue analyses suggest that FRPR-19 acts both in the FLP nociceptive neurons and downstream interneurons, whereas FLP-14 acts from interneurons. Importantly, genetic impairment of the FLP-14/FRPR-19 pathway accelerated the habituation to repeated FLP-specific optogenetic activation, as well as to repeated noxious heat and harsh touch stimuli. Collectively, our data suggest that well-adjusted neuromodulation via the FLP-14/FRPR-19 pathway contributes to promote nociceptive signals in C. elegans and counteracts habituation processes that otherwise tend to rapidly reduce aversive responses to repeated noxious stimuli.
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Affiliation(s)
- Filipe Marques
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Elke Vandewyer
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Isabel Beets
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
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11
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Abstract
Caenorhabditis elegans' behavioral states, like those of other animals, are shaped by its immediate environment, its past experiences, and by internal factors. We here review the literature on C. elegans behavioral states and their regulation. We discuss dwelling and roaming, local and global search, mate finding, sleep, and the interaction between internal metabolic states and behavior.
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Affiliation(s)
- Steven W Flavell
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Young-Jai You
- Division of Biological Science, Graduate School of Science, Nagoya University, 464-8602, Japan
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12
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Huang AY, Taylor AMW, Ghogha A, Pribadi M, Wang Q, Kim TSJ, Cahill CM, Coppola G, Evans CJ. Genetic and functional analysis of a Pacific hagfish opioid system. J Neurosci Res 2020; 100:19-34. [PMID: 32830380 DOI: 10.1002/jnr.24682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/22/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022]
Abstract
The actions of endogenous opioids and nociceptin/orphanin FQ are mediated by four homologous G protein-coupled receptors that constitute the opioid receptor family. However, little is known about opioid systems in cyclostomes (living jawless fish) and how opioid systems might have evolved from invertebrates. Here, we leveraged de novo transcriptome and low-coverage whole-genome assembly in the Pacific hagfish (Eptatretus stoutii) to identify and characterize the first full-length coding sequence for a functional opioid receptor in a cyclostome. Additionally, we define two novel endogenous opioid precursors in this species that predict several novel opioid peptides. Bioinformatic analysis shows no closely related opioid receptor genes in invertebrates with regard either to the genomic organization or to conserved opioid receptor-specific sequences that are common in all vertebrates. Furthermore, no proteins analogous to vertebrate opioid precursors could be identified by genomic searches despite previous claims of protein or RNA-derived sequences in several invertebrate species. The presence of an expressed orthologous receptor and opioid precursors in the Pacific hagfish confirms that a functional opioid system was likely present in the common ancestor of all extant vertebrates some 550 million years ago, earlier than all previous authenticated accounts. We discuss the premise that the cyclostome and vertebrate opioid systems evolved from invertebrate systems concerned with antimicrobial defense and speculate that the high concentrations of opioid precursors in tissues such as the testes, gut, and activated immune cells are key remnants of this evolutionary role.
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Affiliation(s)
- Alden Y Huang
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Anna M W Taylor
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Atefeh Ghogha
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Mochtar Pribadi
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Qing Wang
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Tanya S J Kim
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Catherine M Cahill
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Giovanni Coppola
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Christopher J Evans
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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13
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O'Donnell MP, Fox BW, Chao PH, Schroeder FC, Sengupta P. A neurotransmitter produced by gut bacteria modulates host sensory behaviour. Nature 2020; 583:415-420. [PMID: 32555456 PMCID: PMC7853625 DOI: 10.1038/s41586-020-2395-5] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 03/27/2020] [Indexed: 12/18/2022]
Abstract
Animals coexist in commensal, pathogenic or mutualistic relationships with complex communities of diverse organisms, including microorganisms1. Some bacteria produce bioactive neurotransmitters that have previously been proposed to modulate nervous system activity and behaviours of their hosts2,3. However, the mechanistic basis of this microbiota-brain signalling and its physiological relevance are largely unknown. Here we show that in Caenorhabditis elegans, the neuromodulator tyramine produced by commensal Providencia bacteria, which colonize the gut, bypasses the requirement for host tyramine biosynthesis and manipulates a host sensory decision. Bacterially produced tyramine is probably converted to octopamine by the host tyramine β-hydroxylase enzyme. Octopamine, in turn, targets the OCTR-1 octopamine receptor on ASH nociceptive neurons to modulate an aversive olfactory response. We identify the genes that are required for tyramine biosynthesis in Providencia, and show that these genes are necessary for the modulation of host behaviour. We further find that C. elegans colonized by Providencia preferentially select these bacteria in food choice assays, and that this selection bias requires bacterially produced tyramine and host octopamine signalling. Our results demonstrate that a neurotransmitter produced by gut bacteria mimics the functions of the cognate host molecule to override host control of a sensory decision, and thereby promotes fitness of both the host and the microorganism.
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Affiliation(s)
| | - Bennett W Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Pin-Hao Chao
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA, USA.
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14
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Sizemore TR, Hurley LM, Dacks AM. Serotonergic modulation across sensory modalities. J Neurophysiol 2020; 123:2406-2425. [PMID: 32401124 PMCID: PMC7311732 DOI: 10.1152/jn.00034.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin's capacity for contextualizing sensory information according to the animal's physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Laura M Hurley
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia
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15
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Cong W, Bai R, Li YF, Wang L, Chen C. Selenium Nanoparticles as an Efficient Nanomedicine for the Therapy of Huntington's Disease. ACS APPLIED MATERIALS & INTERFACES 2019; 11:34725-34735. [PMID: 31479233 DOI: 10.1021/acsami.9b12319] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Huntington's disease (HD) is an incurable disease with progressive loss of neural function, which is influenced by epigenetic, oxidative stress, metabolic, and nutritional factors. Targeting inhibition of huntingtin protein aggregation is a strategy for HD therapy, but the efficacy is unsatisfactory. Studies found that selenium (Se) levels in the brain are insufficient for HD disease individuals, while improvement in Se homeostasis in the brain may attenuate neuronal loss and dysfunction. In this study, we applied selenium nanoparticles (NPs) (Nano-Se) for the HD disease therapy by regulating HD-related neurodegeneration and cognitive decline based on transgenic HD models of Caenorhabditis elegans (C. elegans). At low dosages, Nano-Se NPs significantly reduced neuronal death, relieved behavioral dysfunction, and protected C. elegans from damages in stress conditions. The molecular mechanism further revealed that Nano-Se attenuated oxidative stress, inhibited the aggregation of huntingtin proteins, and downregulated the expression of histone deacetylase family members at mRNA levels. The results suggested that Nano-Se has great potential for Huntington's disease therapy. In conclusion, the mechanism about how Nano-Se NPs protect from damages in stress conditions and how they repair neural functions will benefit HD disease therapy. This study will also guide rational design of Nano-Se NPs or other selenium compounds to improve HD therapy in the future.
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Affiliation(s)
- Wenshu Cong
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology of China , Beijing 100190 , China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
- Department of Pharmaceutics, School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China
| | - Ru Bai
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology of China , Beijing 100190 , China
| | - Yu-Feng Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Liming Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Chunying Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology of China , Beijing 100190 , China
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16
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da Silveira TL, Machado ML, Arantes LP, Zamberlan DC, Cordeiro LM, Obetine FBB, da Silva AF, Tassi CL, Soares FAA. Guanosine Prevents against Glutamatergic Excitotoxicity in C. elegans. Neuroscience 2019; 414:265-272. [PMID: 31306683 DOI: 10.1016/j.neuroscience.2019.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 02/08/2023]
Abstract
Glutamatergic neurotransmission is present in most mammalian excitatory synapses and plays a key role in central nervous system homeostasis. When over-activated, it can induce excitotoxicity, which is present in several neuropathologies. The nucleoside guanosine (GUO) is a guanine-based purine known to have neuroprotective effects by modulating glutamatergic system during glutamate excitotoxicity in mammals. However, GUO action in Caenorhabditis elegans, as well as on C. elegans glutamatergic excitotoxicity model, is not known. The GUO effects on behavioral parameters in Wild Type (WT) and knockouts worms for glutamate transporters (GLT-3, GLT-1), glutamate vesicular transporter (EAT-4), and NMDA and non-NMDA receptors were used to evaluate the GUO modulatory effects. The GUO tested concentrations did not alter the animals' development, but GUO reduced pharyngeal pumps in WT animals in a dose-dependent manner. The same effect was observed in pharyngeal pumps, when the animals were treated with 4 mM of GUO in glr-1, nmr-1 and eat-4, but not in glt-3 and glt-3;glt-1 knockouts. The double mutant glt-3; glt-1 for GluTs had decreased body bends and an increased number of reversions. This effect was reverted after treatment with GUO. Furthermore, GUO did not alter the sensory response in worms with altered glutamatergic signaling. Thus, GUO seems to modulate the worm's glutamatergic system in situations of exacerbated glutamatergic signaling, which are represented by knockout strains to glutamate transporters. However, in WT animals, GUO appears to reinforce glutamatergic signaling in specific neurons. Our findings indicate that C. elegans strains are useful models to study new compounds that could be used in glutamate-associated neurodegenerative diseases.
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Affiliation(s)
- Tássia Limana da Silveira
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Marina Lopes Machado
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Leticia Priscilla Arantes
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Daniele Coradini Zamberlan
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Larissa Marafiga Cordeiro
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Fabiane Bicca Baptista Obetine
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Aline Franzen da Silva
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Cintia Letícia Tassi
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Felix Alexandre Antunes Soares
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil.
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17
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Harris G, Wu T, Linfield G, Choi MK, Liu H, Zhang Y. Molecular and cellular modulators for multisensory integration in C. elegans. PLoS Genet 2019; 15:e1007706. [PMID: 30849079 PMCID: PMC6426271 DOI: 10.1371/journal.pgen.1007706] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/20/2019] [Accepted: 01/23/2019] [Indexed: 12/19/2022] Open
Abstract
In the natural environment, animals often encounter multiple sensory cues that are simultaneously present. The nervous system integrates the relevant sensory information to generate behavioral responses that have adaptive values. However, the neuronal basis and the modulators that regulate integrated behavioral response to multiple sensory cues are not well defined. Here, we address this question using a behavioral decision in C. elegans when the animal is presented with an attractive food source together with a repulsive odorant. We identify specific sensory neurons, interneurons and neuromodulators that orchestrate the decision-making process, suggesting that various states and contexts may modulate the multisensory integration. Among these modulators, we characterize a new function of a conserved TGF-β pathway that regulates the integrated decision by inhibiting the signaling from a set of central neurons. Interestingly, we find that a common set of modulators, including the TGF-β pathway, regulate the integrated response to the pairing of different foods and repellents. Together, our results provide mechanistic insights into the modulatory signals regulating multisensory integration. The present study characterizes the modulation of a behavioral decision in C. elegans when the worm is presented with a food lawn that is paired with a repulsive smell. We show that multiple specific sensory neurons and interneurons play roles in making the decision. We also identify several modulatory molecules that are essential for the integrated decision when the animal faces a choice between the cues of opposing valence. We further show that many of these factors, which often represent different states and contexts, are common for behavioral decisions that integrate sensory information from different types of foods and repellents. Overall, our results reveal the molecular and cellular basis for integration of simultaneously present attractive and repulsive cues to fine-tune decision-making.
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Affiliation(s)
- Gareth Harris
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
- * E-mail: (GH); (YZ)
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Gaia Linfield
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
- * E-mail: (GH); (YZ)
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18
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Brewer JC, Olson AC, Collins KM, Koelle MR. Serotonin and neuropeptides are both released by the HSN command neuron to initiate Caenorhabditis elegans egg laying. PLoS Genet 2019; 15:e1007896. [PMID: 30677018 PMCID: PMC6363226 DOI: 10.1371/journal.pgen.1007896] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/05/2019] [Accepted: 12/13/2018] [Indexed: 01/03/2023] Open
Abstract
Neurons typically release both a small-molecule neurotransmitter and one or more neuropeptides, but how these two types of signal from the same neuron might act together remains largely obscure. For example, serotonergic neurons in mammalian brain express the neuropeptide Substance P, but it is unclear how this co-released neuropeptide might modulate serotonin signaling. We studied this issue in C. elegans, in which all serotonergic neurons express the neuropeptide NLP-3. The serotonergic Hermaphrodite Specific Neurons (HSNs) are command motor neurons within the egg-laying circuit which have been shown to release serotonin to initiate egg-laying behavior. We found that egg-laying defects in animals lacking serotonin were far milder than in animals lacking HSNs, suggesting that HSNs must release other signal(s) in addition to serotonin to stimulate egg laying. While null mutants for nlp-3 had only mild egg-laying defects, animals lacking both serotonin and NLP-3 had severe defects, similar to those of animals lacking HSNs. Optogenetic activation of HSNs induced egg laying in wild-type animals, and in mutant animals lacking either serotonin or NLP-3, but failed to induce egg laying in animals lacking both. We recorded calcium activity in the egg-laying muscles of animals lacking either serotonin, NLP-3, or both. The single mutants, and to a greater extent the double mutant, showed muscle activity that was uncoordinated and unable to expel eggs. Specifically, the vm2 muscles cells, which are direct postsynaptic targets of the HSN, failed to contract simultaneously with other egg-laying muscle cells. Our results show that the HSN neurons use serotonin and the neuropeptide NLP-3 as partially redundant co-transmitters that together stimulate and coordinate activity of the target cells onto which they are released. Activity of the brain results from neurons communicating with each other using chemical signals. A typical neuron releases two kinds of chemical signals: a small molecule neurotransmitter, such as serotonin, and one or more small proteins, called neuropeptides. For example, neurons in the human brain that release serotonin, a neurotransmitter thought to be involved in depression, also release the neuropeptide Substance P. Neuroscientists have typically studied the effects of neurotransmitters and neuropeptides separately, without considering how these two types of signals from the same neuron might be integrated. Here we analyzed how specific neurons in the model organism C. elegans use both serotonin and a neuropeptide together. The Hermaphrodite Specific Neurons (HSNs) activate a small group of neurons and muscles to generate egg-laying behavior. Killing the HSNs resulted in animals unable to lay eggs, but we found that eliminating either serotonin or the neuropeptide resulted in HSNs that still remained able to activate egg laying. However, eliminating both serotonin and the neuropeptide resulted in HSNs unable to activate coordinated contractions of the egg-laying muscles. Our results show that in a living animal, serotonin acts in concert with a co-released neuropeptide to carry out its functions.
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Affiliation(s)
- Jacob C. Brewer
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Andrew C. Olson
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Kevin M. Collins
- Department of Biology, University of Miami, Coral Gables, Florida, United States of America
| | - Michael R. Koelle
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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19
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Koelle MR. Neurotransmitter signaling through heterotrimeric G proteins: insights from studies in C. elegans. WORMBOOK : THE ONLINE REVIEW OF C. ELEGANS BIOLOGY 2018; 2018:1-52. [PMID: 26937633 PMCID: PMC5010795 DOI: 10.1895/wormbook.1.75.2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neurotransmitters signal via G protein coupled receptors (GPCRs) to modulate activity of neurons and muscles. C. elegans has ∼150 G protein coupled neuropeptide receptor homologs and 28 additional GPCRs for small-molecule neurotransmitters. Genetic studies in C. elegans demonstrate that neurotransmitters diffuse far from their release sites to activate GPCRs on distant cells. Individual receptor types are expressed on limited numbers of cells and thus can provide very specific regulation of an individual neural circuit and behavior. G protein coupled neurotransmitter receptors signal principally via the three types of heterotrimeric G proteins defined by the G alpha subunits Gαo, Gαq, and Gαs. Each of these G alpha proteins is found in all neurons plus some muscles. Gαo and Gαq signaling inhibit and activate neurotransmitter release, respectively. Gαs signaling, like Gαq signaling, promotes neurotransmitter release. Many details of the signaling mechanisms downstream of Gαq and Gαs have been delineated and are consistent with those of their mammalian orthologs. The details of the signaling mechanism downstream of Gαo remain a mystery. Forward genetic screens in C. elegans have identified new molecular components of neural G protein signaling mechanisms, including Regulators of G protein Signaling (RGS proteins) that inhibit signaling, a new Gαq effector (the Trio RhoGEF domain), and the RIC-8 protein that is required for neuronal Gα signaling. A model is presented in which G proteins sum up the variety of neuromodulator signals that impinge on a neuron to calculate its appropriate output level.
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Affiliation(s)
- Michael R Koelle
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven CT 06520 USA
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20
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Bayer EA, Hobert O. Past experience shapes sexually dimorphic neuronal wiring through monoaminergic signalling. Nature 2018; 561:117-121. [PMID: 30150774 PMCID: PMC6126987 DOI: 10.1038/s41586-018-0452-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/10/2018] [Indexed: 02/02/2023]
Abstract
Differences between female and male brains exist across the animal kingdom and extend from molecular to anatomical features. Here we show that sexually dimorphic anatomy, gene expression and function in the nervous system can be modulated by past experiences. In the nematode Caenorhabditis elegans, sexual differentiation entails the sex-specific pruning of synaptic connections between neurons that are shared by both sexes, giving rise to sexually dimorphic circuits in adult animals1. We discovered that starvation during juvenile stages is memorized in males to suppress the emergence of sexually dimorphic synaptic connectivity. These circuit changes result in increased chemosensory responsiveness in adult males following juvenile starvation. We find that an octopamine-mediated starvation signal dampens the production of serotonin (5-HT) to convey the memory of starvation. Serotonin production is monitored by a 5-HT1A serotonin receptor homologue that acts cell-autonomously to promote the pruning of sexually dimorphic synaptic connectivity under well-fed conditions. Our studies demonstrate how life history shapes neurotransmitter production, synaptic connectivity and behavioural output in a sexually dimorphic circuit.
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Affiliation(s)
- Emily A Bayer
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
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21
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Hori S, Oda S, Suehiro Y, Iino Y, Mitani S. OFF-responses of interneurons optimize avoidance behaviors depending on stimulus strength via electrical synapses. PLoS Genet 2018; 14:e1007477. [PMID: 29939997 PMCID: PMC6034901 DOI: 10.1371/journal.pgen.1007477] [Citation(s) in RCA: 11] [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: 12/18/2017] [Revised: 07/06/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022] Open
Abstract
Optimization of the types and timing of avoidance behaviors depending on the intensity of a noxious stimulus is essential for survival; however, processing in the central nervous system and its developmental basis are largely unknown. Here, we report that Caenorhabditis elegans preferentially selects one of three different types of avoidance behaviors depending on the strength of the noxious stimulus. We screened 210 neuronal transcription factors using a combination of optogenetics and RNA interference methods and identified 19 candidates required for avoidance behaviors. One candidate, gene lin-32 (abnormal cellLINeage32), which encodes an atonal homolog, is required for the neural fate determination of AIB interneurons and functions by regulating the expression of electrical and chemical synapse genes, namely, inx-1 (innexin 1) and AMPA-type ionotropic glutamate receptor glr-1. When examined by Ca imaging, AIB showed an OFF calcium increase to the noxious stimulus. The OFF calcium increase was provoked only by strong stimulation, suggesting a role for optimization of the avoidance behavior. However, lin-32 mutants showed an impaired AIB OFF calcium increase, concomitant with a reduced occurrence of the dynamic avoidance behavior called the "omega turn". The AIB neural responses may be transferred to downstream inter/motor neurons projecting to the neck muscles via electrical synapses comprising inx-1. Finally, we found a correlation between powerful contractions of the neck muscles and omega turns. Thus, the central regulation of the magnitude and timing of activation of the AIB interneurons optimizes the probability of omega turn depending on the stimulus context. For survival, animals exhibit appropriate behaviors depending on the type and strength of a stimulus; however, processing in the central nervous system and its developmental basis are largely unknown. Here, we performed RNA interference screening of 210 transcription factors by observing the avoidance behaviors evoked by a harmful stimulus and identified 19 candidates with behavioral defects. One candidate gene, lin-32, which encodes a homologue of a well-conserved transcription factor, atonal, that plays a key role in cell type specification, is required for the optimization of avoidance behaviors. lin-32 regulates the expression of various synaptic genes in the key neurons required for the optimization of avoidance behaviors. The key neurons respond at the time of the removal of the strong stimulation, and an appropriate magnitude and timing of the calcium increase are required to determine the type and timing of dynamic avoidance behaviors. However, the key neuronal response does not occur in the lin-32 mutants. Activation of the key neurons may be transferred to the downstream neurons projecting to the neck muscles via electrical synapses. Finally, we show a correlation between powerful neck muscle contractions and dynamic avoidance behaviors.
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Affiliation(s)
- Sayaka Hori
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Shigekazu Oda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yuji Suehiro
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
- * E-mail:
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22
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Clark T, Hapiak V, Oakes M, Mills H, Komuniecki R. Monoamines differentially modulate neuropeptide release from distinct sites within a single neuron pair. PLoS One 2018; 13:e0196954. [PMID: 29723289 PMCID: PMC5933757 DOI: 10.1371/journal.pone.0196954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
Monoamines and neuropeptides often modulate the same behavior, but monoaminergic-peptidergic crosstalk remains poorly understood. In Caenorhabditis elegans, the adrenergic-like ligands, tyramine (TA) and octopamine (OA) require distinct subsets of neuropeptides in the two ASI sensory neurons to inhibit nociception. TA selectively increases the release of ASI neuropeptides encoded by nlp-14 or nlp-18 from either synaptic/perisynaptic regions of ASI axons or the ASI soma, respectively, and OA selectively increases the release of ASI neuropeptides encoded by nlp-9 asymmetrically, from only the synaptic/perisynaptic region of the right ASI axon. The predicted amino acid preprosequences of genes encoding either TA- or OA-dependent neuropeptides differed markedly. However, these distinct preprosequences were not sufficient to confer monoamine-specificity and additional N-terminal peptide-encoding sequence was required. Collectively, our results demonstrate that TA and OA specifically and differentially modulate the release of distinct subsets of neuropeptides from different subcellular sites within the ASIs, highlighting the complexity of monoaminergic/peptidergic modulation, even in animals with a relatively simple nervous system.
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Affiliation(s)
- Tobias Clark
- 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
| | - Mitchell Oakes
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Holly Mills
- 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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23
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Thapliyal S, Babu K. C. elegans Locomotion: Finding Balance in Imbalance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1112:185-196. [PMID: 30637699 DOI: 10.1007/978-981-13-3065-0_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The excitation-inhibition (E-I) imbalance in neural circuits represents a hallmark of several neuropsychiatric disorders. The tiny nematode Caenorhabditis elegans has emerged as an excellent system to study the molecular mechanisms underlying this imbalance in neuronal circuits. The C. elegans body wall muscles receive inputs from both excitatory cholinergic and inhibitory GABAergic motor neurons at neuromuscular junctions (NMJ), making it an excellent model for studying the genetic and molecular mechanisms required for maintaining E-I balance at the NMJ. The cholinergic neurons form dyadic synapses wherein they synapse onto ipsilateral body wall muscles allowing for muscle contraction as well as onto GABAergic motor neurons that in turn synapse on the contralateral body wall muscles causing muscle relaxation. An alternating wave of contraction and relaxation mediated by excitatory and inhibitory signals maintains locomotion in C. elegans. This locomotory behavior requires an intricate balance between the excitatory cholinergic signaling and the inhibitory GABAergic signaling mechanisms.Studies on the C. elegans NMJ have provided insights into several molecular mechanisms that could regulate this balance in neural circuits. This review provides a discussion on multiple genetic factors including neuropeptides and their receptors, cell adhesion molecules, and other molecular pathways that have been associated with maintaining E-I balance in C. elegans motor circuits. Further, it also discusses the implications of these studies that could help us in understanding the role of E-I balance in mammalian neural circuits and how changes in this balance could give rise to brain disorders.
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Affiliation(s)
- Shruti Thapliyal
- Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.
| | - Kavita Babu
- Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.
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An automated compound screening for anti-aging effects on the function of C. elegans sensory neurons. Sci Rep 2017; 7:9403. [PMID: 28839194 PMCID: PMC5570957 DOI: 10.1038/s41598-017-09651-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/27/2017] [Indexed: 12/11/2022] Open
Abstract
Discovery of molecular targets or compounds that alter neuronal function can lead to therapeutic advances that ameliorate age-related neurodegenerative pathologies. Currently, there is a lack of in vivo screening technologies for the discovery of compounds that affect the age-dependent neuronal physiology. Here, we present a high-throughput, microfluidic-based assay for automated manipulation and on-chip monitoring and analysis of stimulus-evoked calcium responses of intact C. elegans at various life stages. First, we successfully applied our technology to quantify the effects of aging and age-related genetic and chemical factors in the calcium transients of the ASH sensory neuron. We then performed a large-scale screen of a library of 107 FDA-approved compounds to identify hits that prevented the age-dependent functional deterioration of ASH. The robust performance of our assay makes it a valuable tool for future high-throughput applications based on in vivo functional imaging.
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Opiates Modulate Noxious Chemical Nociception through a Complex Monoaminergic/Peptidergic Cascade. J Neurosci 2017; 36:5498-508. [PMID: 27194330 DOI: 10.1523/jneurosci.4520-15.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/13/2016] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED The ability to detect noxious stimuli, process the nociceptive signal, and elicit an appropriate behavioral response is essential for survival. In Caenorhabditis elegans, opioid receptor agonists, such as morphine, mimic serotonin, and suppress the overall withdrawal from noxious stimuli through a pathway requiring the opioid-like receptor, NPR-17. This serotonin- or morphine-dependent modulation can be rescued in npr-17-null animals by the expression of npr-17 or a human κ opioid receptor in the two ASI sensory neurons, with ASI opioid signaling selectively inhibiting ASI neuropeptide release. Serotonergic modulation requires peptides encoded by both nlp-3 and nlp-24, and either nlp-3 or nlp-24 overexpression mimics morphine and suppresses withdrawal. Peptides encoded by nlp-3 act differentially, with only NLP-3.3 mimicking morphine, whereas other nlp-3 peptides antagonize NLP-3.3 modulation. Together, these results demonstrate that opiates modulate nociception in Caenorhabditis elegans through a complex monoaminergic/peptidergic cascade, and suggest that this model may be useful for dissecting opiate signaling in mammals. SIGNIFICANCE STATEMENT Opiates are used extensively to treat chronic pain. In Caenorhabditis elegans, opioid receptor agonists suppress the overall withdrawal from noxious chemical stimuli through a pathway requiring an opioid-like receptor and two distinct neuropeptide-encoding genes, with individual peptides from the same gene functioning antagonistically to modulate nociception. Endogenous opioid signaling functions as part of a complex, monoaminergic/peptidergic signaling cascade and appears to selectively inhibit neuropeptide release, mediated by a α-adrenergic-like receptor, from two sensory neurons. Importantly, receptor null animals can be rescued by the expression of the human κ opioid receptor, and injection of human opioid receptor ligands mimics exogenous opiates, highlighting the utility of this model for dissecting opiate signaling in mammals.
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Abstract
Colocalization of small-molecule and neuropeptide transmitters is common throughout the nervous system of all animals. The resulting co-transmission, which provides conjoint ionotropic ('classical') and metabotropic ('modulatory') actions, includes neuropeptide- specific aspects that are qualitatively different from those that result from metabotropic actions of small-molecule transmitter release. Here, we focus on the flexibility afforded to microcircuits by such co-transmission, using examples from various nervous systems. Insights from such studies indicate that co-transmission mediated even by a single neuron can configure microcircuit activity via an array of contributing mechanisms, operating on multiple timescales, to enhance both behavioural flexibility and robustness.
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Neuropeptidergic Signaling and Active Feeding State Inhibit Nociception in Caenorhabditis elegans. J Neurosci 2016; 36:3157-69. [PMID: 26985027 DOI: 10.1523/jneurosci.1128-15.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Food availability and nutritional status are important cues affecting behavioral states. Here we report that, in Caenorhabditis elegans, a cascade of dopamine and neuropeptide signaling acts to inhibit nociception in food-poor environments. In the absence of food, animals show decreased sensitivity and increased adaptation to soluble repellents sensed by the polymodal ASH nociceptors. The effects of food on adaptation are affected by dopamine and neuropeptide signaling; dopamine acts via the DOP-1 receptor to decrease adaptation on food, whereas the neuropeptide receptors NPR-1 and NPR-2 act to increase adaptation off food. NPR-1 and NPR-2 function cell autonomously in the ASH neurons to increase adaptation off food, whereas the DOP-1 receptor controls neuropeptide release from interneurons that modulate ASH activity indirectly. These results indicate that feeding state modulates nociception through the interaction of monoamine and neuropeptide signaling pathways.
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Yu Y, Zhi L, Guan X, Wang D, Wang D. FLP-4 neuropeptide and its receptor in a neuronal circuit regulate preference choice through functions of ASH-2 trithorax complex in Caenorhabditis elegans. Sci Rep 2016; 6:21485. [PMID: 26887501 PMCID: PMC4757837 DOI: 10.1038/srep21485] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/25/2016] [Indexed: 01/19/2023] Open
Abstract
Preference choice on food is an important response strategy for animals living in the environment. Using assay system of preference choice on bacterial foods, OP50 and PA14, we identified the involvement of ADL sensory neurons in the control of preference choice in Caenorhabditis elegans. Both genetically silencing and ChR2-mediated activation of ADL sensory neurons significantly affected preference choice. ADL regulated preference choice by inhibiting function of G protein-coupled receptor (GPCR)/SRH-220. ADL sensory neurons might regulate preference choice through peptidergic signals of FLP-4 and NLP-10, and function of FLP-4 or NLP-10 in regulating preference choice was regulated by SRH-220. FLP-4 released from ADL sensory neurons further regulated preference choice through its receptor of NPR-4 in AIB interneurons. In AIB interneurons, NPR-4 was involved in the control of preference choice by activating the functions of ASH-2 trithorax complex consisting of SET-2, ASH-2, and WDR-5, implying the crucial role of molecular machinery of trimethylation of histone H3K4 in the preference choice control. The identified novel neuronal circuit and the underlying molecular mechanisms will strengthen our understanding neuronal basis of preference choice in animals.
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Affiliation(s)
- Yonglin Yu
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Lingtong Zhi
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Xiangmin Guan
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Daoyong Wang
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Dayong Wang
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
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Abstract
UNLABELLED Sensory inputs are integrated extensively before decision making, with altered multisensory integration being associated with disorders such as autism. We demonstrate that the two C. elegans AIB interneurons function as a biphasic switch, integrating antagonistic, tonic, and acute inputs from three distinct pairs of sensory neurons to modulate nociception. Off food, animals reverse away from a noxious stimulus. In contrast, on food or serotonin, AIB signaling is inhibited and, although animals initiate an aversive response more rapidly, they continue forward after the initial backward locomotion is complete. That is, animals continue to move forward and feed even when presented with a noxious repellant, with AIB inhibition decreasing the repellant concentration evoking a maximal response. These studies demonstrate that the AIBs serve as an integrating hub, receiving inputs from different sensory neurons to modulate locomotory decision making differentially, and highlight the utility of this model to analyze the complexities of multisensory integration. SIGNIFICANCE STATEMENT Dysfunctional sensory signaling and perception are associated with a number of disease states, including autism spectrum disorders, schizophrenia, and anxiety. We have used the C. elegans model to examine multisensory integration at the interneuron level to better understand the modulation of this complex, multicomponent process. C. elegans responds to a repulsive odorant by first backing up and then either continuing forward or turning and moving away from the odorant. This decision-making process is modulated extensively by the activity state of the two AIB interneurons, with the AIBs integrating an array of synergistic and antagonistic glutamatergic inputs, from sensory neurons responding directly to the odorant to others responding to a host of additional environmental variables to ultimately fine tune aversive behaviors.
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Campbell JC, Chin-Sang ID, Bendena WG. Mechanosensation circuitry in Caenorhabditis elegans: A focus on gentle touch. Peptides 2015; 68:164-74. [PMID: 25543196 DOI: 10.1016/j.peptides.2014.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 12/14/2014] [Accepted: 12/15/2014] [Indexed: 01/02/2023]
Abstract
Forward or reverse movement in Caenorhabditis elegans is the result of sequential contraction of muscle cells arranged along the body. In larvae, muscle cells are innervated by distinct classes of motorneurons. B motorneurons regulate forward movement and A motorneurons regulate backward movement. Ablation of the D motor neurons results in animals that are uncoordinated in either direction, which suggests that D motorneurons regulate the interaction between the two circuits. C. elegans locomotion is dictated by inputs from interneurons that regulate the activity of motorneurons which coordinate muscle contraction to facilitate forward or backwards movement. As C. elegans moves through the environment, sensory neurons interpret chemical and mechanical information which is relayed to the motor neurons that control locomotory direction. A mechanosensory input known as light nose touch can be simulated in the laboratory by touching the nose of the animal with a human eyebrow hair. The recoil reaction that follows from light nose touch appears to be primarily mediated by glutamate release from the polymodal sensory neuron ASH. Numerous glutamate receptor types are found in different neurons and interneurons which suggest that several pathways may regulate the aversive response. Based on the phenotypes of mutants in which neuropeptide processing is abolished, neuropeptides play a role in circuit regulation. The light touch response is also regulated by transient receptor channel proteins and degenerin/epithelial sodium channels which modulate the activity of sensory neurons involved in the nose touch response.
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Affiliation(s)
- Jason C Campbell
- Department of Biology, Biosciences Complex, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Ian D Chin-Sang
- Department of Biology, Biosciences Complex, Queen's University, Kingston, ON K7L 3N6, Canada
| | - William G Bendena
- Department of Biology, Biosciences Complex, Queen's University, Kingston, ON K7L 3N6, Canada; Centre for Neuroscience, Queen's University, Kingston, ON K7L 3N6, Canada.
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Cheong MC, Artyukhin AB, You YJ, Avery L. An opioid-like system regulating feeding behavior in C. elegans. eLife 2015; 4. [PMID: 25898004 PMCID: PMC4427864 DOI: 10.7554/elife.06683] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/21/2015] [Indexed: 01/29/2023] Open
Abstract
Neuropeptides are essential for the regulation of appetite. Here we show that neuropeptides could regulate feeding in mutants that lack neurotransmission from the motor neurons that stimulate feeding muscles. We identified nlp-24 by an RNAi screen of 115 neuropeptide genes, testing whether they affected growth. NLP-24 peptides have a conserved YGGXX sequence, similar to mammalian opioid neuropeptides. In addition, morphine and naloxone respectively stimulated and inhibited feeding in starved worms, but not in worms lacking NPR-17, which encodes a protein with sequence similarity to opioid receptors. Opioid agonists activated heterologously expressed NPR-17, as did at least one NLP-24 peptide. Worms lacking the ASI neurons, which express npr-17, did not response to naloxone. Thus, we suggest that Caenorhabditis elegans has an endogenous opioid system that acts through NPR-17, and that opioids regulate feeding via ASI neurons. Together, these results suggest C. elegans may be the first genetically tractable invertebrate opioid model. DOI:http://dx.doi.org/10.7554/eLife.06683.001 When and how much an animal eats is controlled by a complex web of signals that are produced by the animal's body and brain. Molecules called opioid neuropeptides are among these signals, and act to control eating in mammals by binding to receptors in the brain and body. These receptors can also bind to similar molecules called opiates (such as morphine); opiates are amongst the oldest drugs used by humans and have diverse effects ranging from pain relief to addiction. While the activities of opiates and opioid neuropeptides have been studied in mammals, relatively little is known about opioid signaling in simpler animals. The mechanisms behind many biological processes have been investigated using a worm called C. elegans as a model system because it has a simple body plan and its genes can be altered easily. The feeding behavior of C. elegans is no exception. This worm feeds by contracting and relaxing its pharyngeal muscle to move food into its gut. When the worms sense that food is available, this ‘pharyngeal pumping’ is regulated by one type of nerve cell. Slow pharyngeal pumping also continues in starved worms when food is not available, possibly to encourage them to eat new potential sources of food. However, this slow pumping does not require the same type of nerve cell. Cheong et al. hypothesized that the slow pumping in starved worms might depend on neuropeptide signaling instead, and have now tested this idea using engineered worms that made lower levels of a number of these molecules. The experiments uncovered a molecule called NLP-24 that promotes the slow pharyngeal pumping. This molecule is similar to opioid neuropeptides found in mammals. Worms that made less NLP-24 than normal grew more slowly; this suggests that they had problems feeding. Moreover, the levels of NLP-24 were found to increase in normal worms soon after they were deprived of food. Further experiments revealed the identity of the receptor for this molecule, which is also similar to mammalian opioid receptors. The discovery that opioid signaling is involved in C. elegans' feeding behavior may well, in future, also help to identify new molecular players involved in opioid signaling. Further studies might also help the search for ways to reduce the problematic side-effects that limit the usefulness of opiate drugs as medicines. DOI:http://dx.doi.org/10.7554/eLife.06683.002
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Affiliation(s)
- Mi Cheong Cheong
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
| | - Alexander B Artyukhin
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
| | - Young-Jai You
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, United States
| | - Leon Avery
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
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Marder E, O'Leary T, Shruti S. Neuromodulation of circuits with variable parameters: single neurons and small circuits reveal principles of state-dependent and robust neuromodulation. Annu Rev Neurosci 2015; 37:329-46. [PMID: 25032499 DOI: 10.1146/annurev-neuro-071013-013958] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neuromodulation underlies many behavioral states and has been extensively studied in small circuits. This has allowed the systematic exploration of how neuromodulatory substances and the neurons that release them can influence circuit function. The physiological state of a network and its level of activity can have profound effects on how the modulators act, a phenomenon known as state dependence. We provide insights from experiments and computational work that show how state dependence can arise and the consequences it can have for cellular and circuit function. These observations pose a general unsolved question that is relevant to all nervous systems: How is robust modulation achieved in spite of animal-to-animal variability and degenerate, nonlinear mechanisms for the production of neuronal and network activity?
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Affiliation(s)
- Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454; , ,
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Guo M, Wu TH, Song YX, Ge MH, Su CM, Niu WP, Li LL, Xu ZJ, Ge CL, Al-Mhanawi MTH, Wu SP, Wu ZX. Reciprocal inhibition between sensory ASH and ASI neurons modulates nociception and avoidance in Caenorhabditis elegans. Nat Commun 2015; 6:5655. [PMID: 25585042 DOI: 10.1038/ncomms6655] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 10/24/2014] [Indexed: 02/02/2023] Open
Abstract
Sensory modulation is essential for animal sensations, behaviours and survival. Peripheral modulations of nociceptive sensations and aversive behaviours are poorly understood. Here we identify a biased cross-inhibitory neural circuit between ASH and ASI sensory neurons. This inhibition is essential to drive normal adaptive avoidance of a CuSO4 (Cu(2+)) challenge in Caenorhabditis elegans. In the circuit, ASHs respond to Cu(2+) robustly and suppress ASIs via electro-synaptically exciting octopaminergic RIC interneurons, which release octopamine (OA), and neuroendocrinally inhibit ASI by acting on the SER-3 receptor. In addition, ASIs sense Cu(2+) and permit a rapid onset of Cu(2+)-evoked responses in Cu(2+)-sensitive ADF neurons via neuropeptides possibly, to inhibit ASHs. ADFs function as interneurons to mediate ASI inhibition of ASHs by releasing serotonin (5-HT) that binds with the SER-5 receptor on ASHs. This elaborate modulation among sensory neurons via reciprocal inhibition fine-tunes the nociception and avoidance behaviour.
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Affiliation(s)
- Min Guo
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Tai-Hong Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Yan-Xue Song
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Ming-Hai Ge
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Chun-Ming Su
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Wei-Pin Niu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Lan-Lan Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Zi-Jing Xu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Chang-Li Ge
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Maha T H Al-Mhanawi
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
| | - Shi-Ping Wu
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, China
| | - Zheng-Xing Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
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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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Komuniecki R, Hapiak V, Harris G, Bamber B. Context-dependent modulation reconfigures interactive sensory-mediated microcircuits in Caenorhabditis elegans. Curr Opin Neurobiol 2014; 29:17-24. [DOI: 10.1016/j.conb.2014.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/04/2014] [Accepted: 04/07/2014] [Indexed: 01/04/2023]
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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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Abstract
Food is critical for survival. Many animals, including the nematode Caenorhabditis elegans, use sensorimotor systems to detect and locate preferred food sources. However, the signaling mechanisms underlying food-choice behaviors are poorly understood. Here, we characterize the molecular signaling that regulates recognition and preference between different food odors in C. elegans. We show that the major olfactory sensory neurons, AWB and AWC, play essential roles in this behavior. A canonical Gα-protein, together with guanylate cyclases and cGMP-gated channels, is needed for the recognition of food odors. The food-odor-evoked signal is transmitted via glutamatergic neurotransmission from AWC and through AMPA and kainate-like glutamate receptor subunits. In contrast, peptidergic signaling is required to generate preference between different food odors while being dispensable for the recognition of the odors. We show that this regulation is achieved by the neuropeptide NLP-9 produced in AWB, which acts with its putative receptor NPR-18, and by the neuropeptide NLP-1 produced in AWC. In addition, another set of sensory neurons inhibits food-odor preference. These mechanistic logics, together with a previously mapped neural circuit underlying food-odor preference, provide a functional network linking sensory response, transduction, and downstream receptors to process complex olfactory information and generate the appropriate behavioral decision essential for survival.
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Lindy AS, Parekh PK, Zhu R, Kanju P, Chintapalli SV, Tsvilovskyy V, Patterson RL, Anishkin A, van Rossum DB, Liedtke WB. TRPV channel-mediated calcium transients in nociceptor neurons are dispensable for avoidance behaviour. Nat Commun 2014; 5:4734. [PMID: 25178952 PMCID: PMC4164786 DOI: 10.1038/ncomms5734] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/17/2014] [Indexed: 12/21/2022] Open
Abstract
Animals need to sense and react to potentially dangerous environments. TRP ion channels participate in nociception, presumably via Ca2+ influx, in most animal species. However, the relationship between ion permeation and animals’ nocifensive behaviour is unknown. Here we use an invertebrate animal model with relevance for mammalian pain. We analyse the putative selectivity filter of OSM-9, a TRPV channel, in osmotic avoidance behaviour of Caenorhabditis elegans. Using mutagenized OSM-9 expressed in the head nociceptor neuron, ASH, we study nocifensive behaviour and Ca2+ influx. Within the selectivity filter, M601-F609, Y604G strongly reduces avoidance behaviour and eliminates Ca2+ transients. Y604F also abolishes Ca2+ transients in ASH, while sustaining avoidance behaviour, yet it disrupts behavioral plasticity. Homology modelling of the OSM-9 pore suggests that Y604 may assume a scaffolding role. Thus, aromatic residues in the OSM-9 selectivity filter are critical for pain behaviour and ion permeation. These findings have relevance for understanding evolutionary roots of mammalian nociception. TRPs are calcium-permeable channels involved in the sensing of damaging stimuli but the relationship between calcium influx and pain behaviour has been elusive. Here the authors find that the TRP channel OSM-9 functions as an ion channel in vivo in C. elegans, and establish residues that are critical for worm pain-like behaviour.
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Affiliation(s)
- Amanda S Lindy
- 1] Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Puja K Parekh
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Richard Zhu
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Patrick Kanju
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sree V Chintapalli
- 1] Department of Membrane Biology and Physiology, University of California, Davis, California 95616, USA [2] Department of Biochemistry and Molecular Medicine, University of California, Davis, California 95616, USA
| | - Volodymyr Tsvilovskyy
- Department of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Randen L Patterson
- 1] Department of Membrane Biology and Physiology, University of California, Davis, California 95616, USA [2] Department of Biochemistry and Molecular Medicine, University of California, Davis, California 95616, USA
| | - Andriy Anishkin
- 1] Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania 16801, USA [2] Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA
| | - Damian B van Rossum
- 1] Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania 16801, USA [2] Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA
| | - Wolfgang B Liedtke
- 1] Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Duke University Clinics for Pain and Palliative Care, 932 Morreene Road, Durham, North Carolina 27705, USA [3] Departments of Anesthesiology and Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA [4] Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Dopamine modulation of avoidance behavior in Caenorhabditis elegans requires the NMDA receptor NMR-1. PLoS One 2014; 9:e102958. [PMID: 25089710 PMCID: PMC4121140 DOI: 10.1371/journal.pone.0102958] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 06/26/2014] [Indexed: 01/01/2023] Open
Abstract
The nematode C. elegans utilizes a relatively simple neural circuit to mediate avoidance responses to noxious stimuli such as the volatile odorant octanol. This avoidance behavior is modulated by dopamine. cat-2 mutant animals that are deficient in dopamine biosynthesis have an increased response latency to octanol compared to wild type animals, and this defect can be fully restored with the application of exogenous dopamine. Because this avoidance behavior is mediated by glutamatergic signaling between sensory neurons and premotor interneurons, we investigated the genetic interactions between dopaminergic signaling and ionotropic glutamate receptors. cat-2 mutant animals lacking either the GLR-1 or GLR-2 AMPA/kainate receptors displayed an increased response latency to octanol, which could be restored via exogenous dopamine. However, whereas cat-2 mutant animals lacking the NMR-1 NMDA receptor had increased response latency to octanol they were insensitive to exogenous dopamine. Mutants that lacked both AMPA/kainate and NMDA receptors were also insensitive to exogenous dopamine. Our results indicate that dopamine modulation of octanol avoidance requires NMR-1, consistent with NMR-1 as a potential downstream signaling target for dopamine.
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Kuo WJ, Sie YS, Chuang HS. Characterizations of kinetic power and propulsion of the nematode Caenorhabditis elegans based on a micro-particle image velocimetry system. BIOMICROFLUIDICS 2014; 8:024116. [PMID: 24803965 PMCID: PMC4000384 DOI: 10.1063/1.4872061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 04/10/2014] [Indexed: 06/02/2023]
Abstract
Quantifying the motility of micro-organisms is beneficial in understanding their biomechanical properties. This paper presents a simple image-based algorithm to derive the kinetic power and propulsive force of the nematode Caenorhabditis elegans. To avoid unnecessary disturbance, each worm was confined in an aqueous droplet of 0.5 μl. The droplet was sandwiched between two glass slides and sealed with mineral oil to prevent evaporation. For motion visualization, 3-μm fluorescent particles were dispersed in the droplet. Since the droplet formed an isolated environment, the fluid drag and energy loss due to wall frictions were associated with the worm's kinetic power and propulsion. A microparticle image velocimetry system was used to acquire consecutive particle images for fluid analysis. The short-time interval (Δt < 20 ms) between images enabled quasi real-time measurements. A numerical simulation of the flow in a straight channel showed that the relative error of this algorithm was significantly mitigated as the image was divided into small interrogation windows. The time-averaged power and propulsive force of a N2 adult worm over three swimming cycles were estimated to be 5.2 ± 3.1 pW and 1.0 ± 0.8 nN, respectively. In addition, a mutant, KG532 [kin-2(ce179) X], and a wild-type (N2) worm in a viscous medium were investigated. Both cases showed an increase in the kinetic power as compared with the N2 worm in the nematode growth medium due to the hyperactive nature of the kin-2 mutant and the high viscosity medium used. Overall, the technique deals with less sophisticated calculations and is automation possible.
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Affiliation(s)
- Wan-Jung Kuo
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yue-Syun Sie
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Han-Sheng Chuang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan ; Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan
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41
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Leinwand SG, Chalasani SH. From genes to circuits and behaviors: Neuropeptides expand the coding potential of the nervous system. WORM 2014; 3:e27730. [PMID: 25254145 PMCID: PMC4165544 DOI: 10.4161/worm.27730] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 12/21/2013] [Accepted: 01/03/2014] [Indexed: 12/18/2022]
Abstract
Neuropeptide signaling remodels the composition of a chemosensory circuit and shapes behavior in Caenorhabditis elegans. We reported that the ASE left (ASEL) salt sensory neuron uses a proprotein convertase, BLI-4, to cleave the insulin-like peptide INS-6. INS-6 peptides are released from the ASEL neuron in response to large, but not small changes in salt stimuli. Fast INS-6 signaling functionally transforms the AWC olfactory sensory neuron into an interneuron in the neural circuit for high salt. This new circuit configuration potentiates behavioral attraction to high salt. Here, in the context of genes, circuits, and behaviors, we discuss the diverse modes of neuropeptide processing and signaling, which expand the coding potential of the nervous system. First, neuropeptide processing and release genes prepare insulin peptides to signal in the nervous system. Second, this neuropeptide signaling diversifies the communication of neural circuits and introduces circuit-level flexibility. Finally, the resulting multisensory neurons and circuits drive finely tuned behavioral choices.
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Affiliation(s)
- Sarah G Leinwand
- Neurosciences Graduate Program; University of California San Diego; La Jolla, CA USA ; Molecular Neurobiology Laboratory; The Salk Institute for Biological Studies; La Jolla, CA USA
| | - Sreekanth H Chalasani
- Neurosciences Graduate Program; University of California San Diego; La Jolla, CA USA ; Molecular Neurobiology Laboratory; The Salk Institute for Biological Studies; La Jolla, CA USA
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Mills H, Hapiak V, Harris G, Summers P, Komuniecki R. The interaction of octopamine and neuropeptides to slow aversive responses in C. elegans mimics the modulation of chronic pain in mammals. WORM 2013; 1:202-6. [PMID: 24058849 PMCID: PMC3670219 DOI: 10.4161/worm.20467] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 12/19/2022]
Abstract
Octopamine (OA) appears to function as the invertebrate counterpart of norepinephrine (NE) in the modulation of a number of key behaviors. In C. elegans, OA signaling is complex, mediated by at least three distinct α-adrenergic-like receptors and appears to activate more global peptidergic signaling cascades that have the potential to dramatically amplify the octopaminergic signal. These OA-dependent peptidergic signaling cascades involve an array of neuropeptides that activate receptors throughout the nervous system and have the potential to both directly and indirectly modulate locomotory decision-making. In this commentary we highlight the use of C. elegans as a model to expand our understanding of noradrenergic signaling in mammals, specifically as it relates to the role of NE in anti-nociception.
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Affiliation(s)
- Holly Mills
- Department of Biological Sciences; University of Toledo; Toledo, OH USA
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Hofler C, Koelle MR. The G protein regulator AGS-3 allows C. elegans to alter behaviors in response to food deprivation. WORM 2013; 1:56-60. [PMID: 24058824 PMCID: PMC3670173 DOI: 10.4161/worm.19042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Behavioral responses to food deprivation are a fundamental aspect of nervous system function in all animals. In humans, these behavioral responses prevent dieting from being an effective remedy for obesity. Several signaling molecules in the mammalian brain act through G proteins of the Gαi/o family to mediate responses to food restriction. The mechanisms for neural response to food deprivation may be conserved across species, allowing the power of genetic model organisms to generate insights relevant to the problem of human obesity. In a recent study, we found that C. elegans uses Gαo signaling to mediate a number of behavioral changes that occur after food deprivation. Food deprivation causes biochemical changes in the G Protein Regulator (GPR) domain protein AGS-3 and AGS-3, together with the guanine nucleotide exchange factor RIC-8, activates Gαo signaling to alter food-seeking behavior. These proteins are all conserved in the human brain. Thus the study of behavioral responses to food deprivation in C. elegans may reveal the details of conserved molecular mechanisms underlying neural responses to food deprivation.
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Artyukhin AB, Yim JJ, Srinivasan J, Izrayelit Y, Bose N, von Reuss SH, Jo Y, Jordan JM, Baugh LR, Cheong M, Sternberg PW, Avery L, Schroeder FC. Succinylated octopamine ascarosides and a new pathway of biogenic amine metabolism in Caenorhabditis elegans. J Biol Chem 2013; 288:18778-83. [PMID: 23689506 PMCID: PMC3696653 DOI: 10.1074/jbc.c113.477000] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/13/2013] [Indexed: 11/06/2022] Open
Abstract
The ascarosides, small-molecule signals derived from combinatorial assembly of primary metabolism-derived building blocks, play a central role in Caenorhabditis elegans biology and regulate many aspects of development and behavior in this model organism as well as in other nematodes. Using HPLC-MS/MS-based targeted metabolomics, we identified novel ascarosides incorporating a side chain derived from succinylation of the neurotransmitter octopamine. These compounds, named osas#2, osas#9, and osas#10, are produced predominantly by L1 larvae, where they serve as part of a dispersal signal, whereas these ascarosides are largely absent from the metabolomes of other life stages. Investigating the biogenesis of these octopamine-derived ascarosides, we found that succinylation represents a previously unrecognized pathway of biogenic amine metabolism. At physiological concentrations, the neurotransmitters serotonin, dopamine, and octopamine are converted to a large extent into the corresponding succinates, in addition to the previously described acetates. Chemically, bimodal deactivation of biogenic amines via acetylation and succinylation parallels posttranslational modification of proteins via acetylation and succinylation of L-lysine. Our results reveal a small-molecule connection between neurotransmitter signaling and interorganismal regulation of behavior and suggest that ascaroside biosynthesis is based in part on co-option of degradative biochemical pathways.
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Affiliation(s)
- Alexander B. Artyukhin
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
- the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Joshua J. Yim
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Jagan Srinivasan
- the Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, California 91125, and
| | - Yevgeniy Izrayelit
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Neelanjan Bose
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Stephan H. von Reuss
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Yeara Jo
- the Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, California 91125, and
| | - James M. Jordan
- the Department of Biology, Duke Center for Systems Biology, Duke University, Durham, North Carolina 27708
| | - L. Ryan Baugh
- the Department of Biology, Duke Center for Systems Biology, Duke University, Durham, North Carolina 27708
| | - Micheong Cheong
- the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Paul W. Sternberg
- the Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, California 91125, and
| | - Leon Avery
- the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Frank C. Schroeder
- From the Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
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45
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Belfer SJ, Chuang HS, Freedman BL, Yuan J, Norton M, Bau HH, Raizen DM. Caenorhabditis-in-drop array for monitoring C. elegans quiescent behavior. Sleep 2013; 36:689-698G. [PMID: 23633751 DOI: 10.5665/sleep.2628] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To develop a method, called Caenorhabditis-in-Drop (CiD), encapsulating single worms in aqueous drops, for parallel analysis of behavioral quiescence in C. elegans nematodes. DESIGN We designed, constructed, and tested a device that houses an array of aqueous droplets laden with individual worms. The droplets are separated and covered by immiscible, biocompatible oil. We modeled gas exchange across the aqueous/oil interface and tested the viability of the encapsulated animals. We studied the behavior of wild-type animals; of animals with a loss of function mutation in the cGMP-dependent protein kinase gene egl-4; of animals with a loss of function mutation in the gene kin-2, which encodes a cAMP-dependent protein kinase A regulatory subunit; of animals with a gain-of-function mutation in the gene acy-1, which encodes an adenylate cyclase; and of animals that express high levels of the EGF protein encoded by lin-3. MEASUREMENTS AND RESULTS We used CiD to simultaneously monitor the behavior of 24 worms, a nearly 5-fold improvement over the prior best methodology. In support of our gas exchange models, we found that worms remain viable on the chip for 4 days, past the 12-h period needed for observation, but show reduced longevity to that measured on an agar surface. Measurements of duration of lethargus quiescence and total leth-argus quiescence showed reduced amounts as well as reduced variability relative to prior methods. There was reduced lethargus quiescence in animals that were mutant for kin-2 and for acy-1, supporting a wake-promoting effect of PKA in C. elegans, but no change in lethargus quiescence in egl-4 mutants. There was increased quiescence in animals that expressed kin-2 in the nervous system or over-expressed EGF. CONCLUSIONS CiD is useful for the analysis of behavioral quiescence during lethargus as well as during the adult stage C. elegans. The method is expandable to parallel simultaneous monitoring of hundreds of animals and for other studies of long-term behavior. Using this method, we were successful in measuring, for the first time, quiescence in kin-2(ce179) and in acy-2(ce2) mutants, which are hyperactive. Our observations also highlight the impact of environmental conditions on quiescent behavior and show that longevity is reduced in CiD in comparison to agar surfaces.
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Affiliation(s)
- Samuel J Belfer
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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Dacks AM, Weiss KR. Release of a single neurotransmitter from an identified interneuron coherently affects motor output on multiple time scales. J Neurophysiol 2013; 109:2327-34. [PMID: 23407357 DOI: 10.1152/jn.01079.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurotransmitters can have diverse effects that occur over multiple time scales often making the consequences of neurotransmission difficult to predict. To explore the consequences of this diversity, we used the buccal ganglion of Aplysia to examine the effects of GABA release by a single interneuron, B40, on the intrinsic properties and motor output of the radula closure neuron B8. B40 induces a picrotoxin-sensitive fast IPSP lasting milliseconds in B8 and a slow EPSP lasting seconds. We found that the excitatory effects of this slow EPSP are also mediated by GABA. Together, these two GABAergic actions structure B8 firing in a pattern characteristic of ingestive programs. Furthermore, we found that repeated B40 stimulation induces a persistent increase in B8 excitability that was occluded in the presence of the GABA B receptor agonist baclofen, suggesting that GABA affects B8 excitability over multiple time scales. The phasing of B8 activity during the feeding motor programs determines the nature of the behavior elicited during that motor program. The persistent increase in B8 excitability induced by B40 biased the activity of B8 during feeding motor programs causing the motor programs to become more ingestive in nature. Thus, a single transmitter released from a single interneuron can have consequences for motor output that are expressed over multiple time scales. Importantly, despite the differences in their signs and temporal characteristics, the three actions of B40 are coherent in that they promote B8 firing patterns that are characteristic of ingestive motor outputs.
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Affiliation(s)
- Andrew M Dacks
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, USA.
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47
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Curran KP, Chalasani SH. Serotonin circuits and anxiety: what can invertebrates teach us? INVERTEBRATE NEUROSCIENCE : IN 2012; 12:81-92. [PMID: 22918570 PMCID: PMC3505513 DOI: 10.1007/s10158-012-0140-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/26/2012] [Indexed: 11/08/2022]
Abstract
Fear, a reaction to a threatening situation, is a broadly adaptive feature crucial to the survival and reproductive fitness of individual organisms. By contrast, anxiety is an inappropriate behavioral response often to a perceived, not real, threat. Functional imaging, biochemical analysis, and lesion studies with humans have identified the HPA axis and the amygdala as key neuroanatomical regions driving both fear and anxiety. Abnormalities in these biological systems lead to misregulated fear and anxiety behaviors such as panic attacks and post-traumatic stress disorders. These behaviors are often treated by increasing serotonin levels at synapses, suggesting a role for serotonin signaling in ameliorating both fear and anxiety. Interestingly, serotonin signaling is highly conserved between mammals and invertebrates. We propose that genetically tractable invertebrate models organisms, such as Drosophila melanogaster and Caenorhabditis elegans, are ideally suited to unravel the complexity of the serotonin signaling pathways. These model systems possess well-defined neuroanatomies and robust serotonin-mediated behavior and should reveal insights into how serotonin can modulate human cognitive functions.
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Affiliation(s)
- Kevin P. Curran
- Molecular Neurobiology Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037 USA
| | - Sreekanth H. Chalasani
- Molecular Neurobiology Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037 USA
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48
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Anderson A, McMullan R. G-proteins: Fighting infection on two fronts. WORM 2012; 1:196-201. [PMID: 24058848 PMCID: PMC3670218 DOI: 10.4161/worm.20466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 04/17/2012] [Accepted: 04/23/2012] [Indexed: 11/19/2022]
Abstract
Animals have evolved multiple strategies for coping with the presence of pathogenic microbes. The best characterized is the immune response where animals activate their physical and cellular defenses to respond to invading microorganisms. However, behavioral changes can also be triggered by exposure to microbes and play an important role in defending many species, including humans, from pathogen attack. In our recent study we demonstrate that, following infection, C. elegans uses the same G-protein signaling pathway in neurons and epithelial cells to coordinate avoidance behaviors and immune responses. Coordination of these responses allows animals to mount an immune response to the immediate threat while simultaneously taking action to remove the pathogen, however, the complicated nature of the mammalian brain and immune system has made it difficult to identify the molecular mechanisms mediating these interactions. With its simple, well described, nervous system and a rapidly growing understanding of its immune system, C. elegans has emerged as an excellent model to study the mechanisms by which animals recognize pathogens and coordinate behavioral and immune responses to infection.
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Affiliation(s)
- Alexandra Anderson
- Division of Cell and Molecular Biology; Imperial College London; London, UK
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49
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Sengupta P. The belly rules the nose: feeding state-dependent modulation of peripheral chemosensory responses. Curr Opin Neurobiol 2012; 23:68-75. [PMID: 22939570 DOI: 10.1016/j.conb.2012.08.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 07/25/2012] [Accepted: 08/02/2012] [Indexed: 10/27/2022]
Abstract
Feeding history and the presence of food dramatically alter chemosensory behaviors. Recent results indicate that internal nutritional state can gate peripheral gustatory and olfactory sensory responses to affect behavior. Focusing primarily on recent work in C. elegans and Drosophila, I describe the neuromodulatory mechanisms that translate feeding state information into changes in chemosensory neuron response properties and behavioral output.
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Affiliation(s)
- Piali Sengupta
- Department of Biology and the National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, United States.
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50
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McMullan R, Anderson A, Nurrish S. Behavioral and immune responses to infection require Gαq- RhoA signaling in C. elegans. PLoS Pathog 2012; 8:e1002530. [PMID: 22359503 PMCID: PMC3280986 DOI: 10.1371/journal.ppat.1002530] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 12/28/2011] [Indexed: 11/18/2022] Open
Abstract
Following pathogen infection the hosts' nervous and immune systems react with coordinated responses to the danger. A key question is how the neuronal and immune responses to pathogens are coordinated, are there common signaling pathways used by both responses? Using C. elegans we show that infection by pathogenic strains of M. nematophilum, but not exposure to avirulent strains, triggers behavioral and immune responses both of which require a conserved Gαq-RhoGEF Trio-Rho signaling pathway. Upon infection signaling by the Gαq pathway within cholinergic motorneurons is necessary and sufficient to increase release of the neurotransmitter acetylcholine and increase locomotion rates and these behavioral changes result in C. elegans leaving lawns of M. nematophilum. In the immune response to infection signaling by the Gαq pathway within rectal epithelial cells is necessary and sufficient to cause changes in cell morphology resulting in tail swelling that limits the infection. These Gαq mediated behavioral and immune responses to infection are separate, act in a cell autonomous fashion and activation of this pathway in the appropriate cells can trigger these responses in the absence of infection. Within the rectal epithelium the Gαq signaling pathway cooperates with a Ras signaling pathway to activate a Raf-ERK-MAPK pathway to trigger the cell morphology changes, whereas in motorneurons Gαq signaling triggers behavioral responses independent of Ras signaling. Thus, a conserved Gαq pathway cooperates with cell specific factors in the nervous and immune systems to produce appropriate responses to pathogen. Thus, our data suggests that ligands for Gq coupled receptors are likely to be part of the signals generated in response to M. nematophilum infection. Once infected by a pathogen the nervous and immune systems of many animals react with coordinated responses to the danger. A key question is what are the pathways by which responses to infection occur and to what extent are the same pathways involved in differing responses? Here we demonstrate that a Gαq-RhoA pathway is required for both behavioral and immune responses to infection in C. elegans. We show that Gαq-RhoA signaling is a late step in the response to infection and their site of action defines the cellular targets of signals generated internally in response to infection. One response is to move away from sites of pathogenic bacteria and Gαq-RhoA signaling acts in motorneurons to achieve this. A second response is an innate immune response where Gαq-RhoA signaling acts within cells close to sites of infection, the rectal epithelial cells, to cause major changes in their size and shape to mitigate the effects of infection. Our work demonstrates that ligands for Gq coupled GPCRs are likely to be required for response to infection. Identifying these ligands and the cells that release them will help define the mechanisms by which C. elegans recognizes pathogens and coordinates behavioral and immune responses to infection.
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Affiliation(s)
- Rachel McMullan
- MRC Cell Biology Unit, MRC Laboratory for Molecular Cell Biology and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
- * E-mail: (RM); (SN)
| | - Alexandra Anderson
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Stephen Nurrish
- MRC Cell Biology Unit, MRC Laboratory for Molecular Cell Biology and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- * E-mail: (RM); (SN)
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