1
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Jelen M, Musso PY, Junca P, Gordon MD. Optogenetic induction of appetitive and aversive taste memories in Drosophila. eLife 2023; 12:e81535. [PMID: 37750673 PMCID: PMC10561975 DOI: 10.7554/elife.81535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/22/2023] [Indexed: 09/27/2023] Open
Abstract
Tastes typically evoke innate behavioral responses that can be broadly categorized as acceptance or rejection. However, research in Drosophila melanogaster indicates that taste responses also exhibit plasticity through experience-dependent changes in mushroom body circuits. In this study, we develop a novel taste learning paradigm using closed-loop optogenetics. We find that appetitive and aversive taste memories can be formed by pairing gustatory stimuli with optogenetic activation of sensory neurons or dopaminergic neurons encoding reward or punishment. As with olfactory memories, distinct dopaminergic subpopulations drive the parallel formation of short- and long-term appetitive memories. Long-term memories are protein synthesis-dependent and have energetic requirements that are satisfied by a variety of caloric food sources or by direct stimulation of MB-MP1 dopaminergic neurons. Our paradigm affords new opportunities to probe plasticity mechanisms within the taste system and understand the extent to which taste responses depend on experience.
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Affiliation(s)
- Meghan Jelen
- Department of Zoology and Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Pierre-Yves Musso
- Department of Zoology and Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Pierre Junca
- Department of Zoology and Life Sciences Institute, University of British ColumbiaVancouverCanada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British ColumbiaVancouverCanada
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2
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Taruno A, Gordon MD. Molecular and Cellular Mechanisms of Salt Taste. Annu Rev Physiol 2023; 85:25-45. [PMID: 36332657 DOI: 10.1146/annurev-physiol-031522-075853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Salt taste, the taste of sodium chloride (NaCl), is mechanistically one of the most complex and puzzling among basic tastes. Sodium has essential functions in the body but causes harm in excess. Thus, animals use salt taste to ingest the right amount of salt, which fluctuates by physiological needs: typically, attraction to low salt concentrations and rejection of high salt. This concentration-valence relationship is universally observed in terrestrial animals, and research has revealed complex peripheral codes for NaCl involving multiple taste pathways of opposing valence. Sodium-dependent and -independent pathways mediate attraction and aversion to NaCl, respectively. Gustatory sensors and cells that transduce NaCl have been uncovered, along with downstream signal transduction and neurotransmission mechanisms. However, much remains unknown. This article reviews classical and recent advances in our understanding of the molecular and cellular mechanisms underlying salt taste in mammals and insects and discusses perspectives on human salt taste.
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Affiliation(s)
- Akiyuki Taruno
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan; .,Japan Science and Technology Agency, CREST, Saitama, Japan
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
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3
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McDowell SAT, Stanley M, Gordon MD. A molecular mechanism for high salt taste in Drosophila. Curr Biol 2022; 32:3070-3081.e5. [PMID: 35772408 DOI: 10.1016/j.cub.2022.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/04/2022] [Accepted: 06/07/2022] [Indexed: 11/25/2022]
Abstract
Dietary salt detection and consumption are crucial to maintaining fluid and ionic homeostasis. To optimize salt intake, animals employ salt-dependent activation of multiple taste pathways. Generally, sodium activates attractive taste cells, but attraction is overridden at high salt concentrations by cation non-selective activation of aversive taste cells. In flies, high salt avoidance is driven by both "bitter" taste neurons and a class of glutamatergic "high salt" neurons expressing pickpocket23 (ppk23). Although the cellular basis of salt taste has been described, many of the molecular mechanisms remain elusive. Here, we show that ionotropic receptor 7c (IR7c) is expressed in glutamatergic high salt neurons, where it functions with co-receptors IR76b and IR25a to detect high salt and is essential for monovalent salt taste. Misexpression of IR7c in sweet neurons, which endogenously express IR76b and IR25a, confers responsiveness to non-sodium salts, indicating that IR7c is sufficient to convert a sodium-selective gustatory receptor neuron to a cation non-selective one. Furthermore, the resultant transformation of taste neuron tuning switches potassium chloride from an aversive to an attractive tastant. This research provides insight into the molecular basis of monovalent and divalent salt-taste coding.
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Affiliation(s)
- Sasha A T McDowell
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Molly Stanley
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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4
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Musso PY, Junca P, Gordon MD. A neural circuit linking two sugar sensors regulates satiety-dependent fructose drive in Drosophila. Sci Adv 2021; 7:eabj0186. [PMID: 34851668 PMCID: PMC8635442 DOI: 10.1126/sciadv.abj0186] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In flies, neuronal sensors detect prandial changes in circulating fructose levels and either sustain or terminate feeding, depending on internal state. Here, we describe a three-part neural circuit that imparts satiety-dependent modulation of fructose sensing. We show that dorsal fan-shaped body neurons display oscillatory calcium activity when hemolymph glucose is high and that these oscillations require glutamatergic input from SLP-AB or “Janus” neurons projecting from the protocerebrum to the asymmetric body. Suppression of activity in this circuit, either by starvation or by genetic silencing, promotes specific drive for fructose ingestion. This is achieved through neuropeptidergic signaling by tachykinin, which is released from the fan-shaped body when glycemia is high. Tachykinin, in turn, signals to Gr43a-positive fructose sensors to modulate their response to fructose. Together, our results demonstrate how a three-layer neural circuit links the detection of two sugars to produce precise satiety-dependent control of feeding behavior.
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5
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Stanley M, Ghosh B, Weiss ZF, Christiaanse J, Gordon MD. Mechanisms of lactic acid gustatory attraction in Drosophila. Curr Biol 2021; 31:3525-3537.e6. [PMID: 34197729 DOI: 10.1016/j.cub.2021.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/30/2021] [Accepted: 06/02/2021] [Indexed: 01/05/2023]
Abstract
Sour has been studied almost exclusively as an aversive taste modality. Yet recent work in Drosophila demonstrates that specific carboxylic acids are attractive at ecologically relevant concentrations. Here, we demonstrate that lactic acid is an appetitive and energetic tastant, which stimulates feeding through activation of sweet gustatory receptor neurons (GRNs). This activation displays distinct, mechanistically separable stimulus onset and removal phases. Ionotropic receptor 25a (IR25a) primarily mediates the onset response, which shows specificity for the lactate anion and drives feeding initiation through proboscis extension. Conversely, sweet gustatory receptors (Gr64a-f) mediate a non-specific removal response to low pH that primarily impacts ingestion. While mutations in either receptor family have marginal impacts on feeding, lactic acid attraction is completely abolished in combined mutants. Thus, specific components of lactic acid are detected through two classes of receptors to activate a single set of sensory neurons in physiologically distinct ways, ultimately leading to robust behavioral attraction.
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Affiliation(s)
- Molly Stanley
- Department of Zoology and Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Britya Ghosh
- Department of Zoology and Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; Graduate Program in Cell and Developmental Biology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Zachary F Weiss
- Department of Zoology and Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Jaime Christiaanse
- Department of Zoology and Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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Lau CKS, Jelen M, Gordon MD. A closed-loop optogenetic screen for neurons controlling feeding in Drosophila. G3 (Bethesda) 2021; 11:6170659. [PMID: 33714999 PMCID: PMC8104954 DOI: 10.1093/g3journal/jkab073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 03/03/2021] [Indexed: 11/14/2022]
Abstract
Feeding is an essential part of animal life that is greatly impacted by the sense of taste. Although the characterization of taste-detection at the periphery has been extensive, higher order taste and feeding circuits are still being elucidated. Here, we use an automated closed-loop optogenetic activation screen to detect novel taste and feeding neurons in Drosophila melanogaster. Out of 122 Janelia FlyLight Project GAL4 lines preselected based on expression pattern, we identify six lines that acutely promote feeding and 35 lines that inhibit it. As proof of principle, we follow up on R70C07-GAL4, which labels neurons that strongly inhibit feeding. Using split-GAL4 lines to isolate subsets of the R70C07-GAL4 population, we find both appetitive and aversive neurons. Furthermore, we show that R70C07-GAL4 labels putative second-order taste interneurons that contact both sweet and bitter sensory neurons. These results serve as a resource for further functional dissection of fly feeding circuits.
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Affiliation(s)
- Celia K S Lau
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Meghan Jelen
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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7
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Muria A, Musso PY, Durrieu M, Portugal FR, Ronsin B, Gordon MD, Jeanson R, Isabel G. Social facilitation of long-lasting memory is mediated by CO 2 in Drosophila. Curr Biol 2021; 31:2065-2074.e5. [PMID: 33740428 DOI: 10.1016/j.cub.2021.02.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/22/2020] [Accepted: 02/17/2021] [Indexed: 01/05/2023]
Abstract
How social interactions influence cognition is a fundamental question, yet rarely addressed at the neurobiological level. It is well established that the presence of conspecifics affects learning and memory performance, but the neural basis of this process has only recently begun to be investigated. In the fruit fly Drosophila melanogaster, the presence of other flies improves retrieval of a long-lasting olfactory memory. Here, we demonstrate that this is a composite memory composed of two distinct elements. One is an individual memory that depends on outputs from the α'β' Kenyon cells (KCs) of the mushroom bodies (MBs), the memory center in the insect brain. The other is a group memory requiring output from the αβ KCs, a distinct sub-part of the MBs. We show that social facilitation of memory increases with group size and is triggered by CO2 released by group members. Among the different known neurons carrying CO2 information in the brain, we establish that the bilateral ventral projection neuron (biVPN), which projects onto the MBs, is necessary for social facilitation. Moreover, we demonstrate that CO2-evoked memory engages a serotoninergic pathway involving the dorsal-paired medial (DPM) neurons, revealing a new role for this pair of serotonergic neurons. Overall, we identified both the sensorial cue and the neural circuit (biVPN>αβ>DPM>αβ) governing social facilitation of memory in flies. This study provides demonstration that being in a group recruits the expression of a cryptic memory and that variations in CO2 concentration can affect cognitive processes in insects.
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Affiliation(s)
- Aurélie Muria
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Pierre-Yves Musso
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France; Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Matthias Durrieu
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Felipe Ramon Portugal
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174), Université de Toulouse, CNRS, IRD, 118 route de Narbonne, Bat 4R1, 31062 Toulouse Cedex 9, France; Ecole Nationale Supérieure Formation de l'Enseignement Agricole, Castanet-Tolosan, France
| | - Brice Ronsin
- CBI, Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Michael D Gordon
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Raphaël Jeanson
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Guillaume Isabel
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France.
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8
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Duan J, Zhao Y, Li H, Habernig L, Gordon MD, Miao X, Engström Y, Büttner S. Bab2 Functions as an Ecdysone-Responsive Transcriptional Repressor during Drosophila Development. Cell Rep 2020; 32:107972. [PMID: 32726635 DOI: 10.1016/j.celrep.2020.107972] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/30/2020] [Accepted: 07/08/2020] [Indexed: 12/01/2022] Open
Abstract
Drosophila development is governed by distinct ecdysone steroid pulses that initiate spatially and temporally defined gene expression programs. The translation of these signals into tissue-specific responses is crucial for metamorphosis, but the mechanisms that confer specificity to systemic ecdysone pulses are far from understood. Here, we identify Bric-à-brac 2 (Bab2) as an ecdysone-responsive transcriptional repressor that controls temporal gene expression during larval to pupal transition. Bab2 is necessary to terminate Salivary gland secretion (Sgs) gene expression, while premature Bab2 expression blocks Sgs genes and causes precocious salivary gland histolysis. The timely expression of bab2 is controlled by the ecdysone-responsive transcription factor Broad, and manipulation of EcR/USP/Broad signaling induces inappropriate Bab2 expression and termination of Sgs gene expression. Bab2 directly binds to Sgs loci in vitro and represses all Sgs genes in vivo. Our work characterizes Bab2 as a temporal regulator of somatic gene expression in response to systemic ecdysone signaling.
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Affiliation(s)
- Jianli Duan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yunpo Zhao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China; Department of Zoology, Life Science Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
| | - Haichao Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Michael D Gordon
- Department of Zoology, Life Science Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Xuexia Miao
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
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Stanley M, McDowell SAT, Gordon MD. A fly rhodopsin sheds light on thermal taste. Cell Calcium 2020; 91:102259. [PMID: 32739609 DOI: 10.1016/j.ceca.2020.102259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 07/23/2020] [Accepted: 07/23/2020] [Indexed: 11/18/2022]
Abstract
In their recent paper, Li and colleagues discover that cold food tastes less sweet to flies, in part by activating bitter sensory neurons through a rhodopsin-dependent mechanism [1]. This work establishes temperature as an important variable in understanding fly taste processing and adds diversity to the sensory roles for rhodopsin receptors.
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Affiliation(s)
- Molly Stanley
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Sasha A T McDowell
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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10
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Musso PY, Junca P, Jelen M, Feldman-Kiss D, Zhang H, Chan RC, Gordon MD. Closed-loop optogenetic activation of peripheral or central neurons modulates feeding in freely moving Drosophila. eLife 2019; 8:45636. [PMID: 31322499 PMCID: PMC6668987 DOI: 10.7554/elife.45636] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/18/2019] [Indexed: 12/25/2022] Open
Abstract
Manipulating feeding circuits in freely moving animals is challenging, in part because the timing of sensory inputs is affected by the animal's behavior. To address this challenge in Drosophila, we developed the Sip-Triggered Optogenetic Behavior Enclosure ('STROBE'). The STROBE is a closed-looped system for real-time optogenetic activation of feeding flies, designed to evoke neural excitation coincident with food contact. We previously demonstrated the STROBE's utility in probing the valence of fly sensory neurons (Jaeger et al., 2018). Here we provide a thorough characterization of the STROBE system, demonstrate that STROBE-driven behavior is modified by hunger and the presence of taste ligands, and find that mushroom body dopaminergic input neurons and their respective post-synaptic partners drive opposing feeding behaviors following activation. Together, these results establish the STROBE as a new tool for dissecting fly feeding circuits and suggest a role for mushroom body circuits in processing naïve taste responses.
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Affiliation(s)
- Pierre-Yves Musso
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Pierre Junca
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Meghan Jelen
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Damian Feldman-Kiss
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Han Zhang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Rachel Cw Chan
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Michael D Gordon
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
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Jaeger AH, Stanley M, Weiss ZF, Musso PY, Chan RC, Zhang H, Feldman-Kiss D, Gordon MD. A complex peripheral code for salt taste in Drosophila. eLife 2018; 7:37167. [PMID: 30307393 PMCID: PMC6181562 DOI: 10.7554/elife.37167] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 09/14/2018] [Indexed: 01/20/2023] Open
Abstract
Each taste modality is generally encoded by a single, molecularly defined, population of sensory cells. However, salt stimulates multiple taste pathways in mammals and insects, suggesting a more complex code for salt taste. Here, we examine salt coding in Drosophila. After creating a comprehensive molecular map comprised of five discrete sensory neuron classes across the fly labellum, we find that four are activated by salt: two exhibiting characteristics of ‘low salt’ cells, and two ‘high salt’ classes. Behaviorally, low salt attraction depends primarily on ‘sweet’ neurons, with additional input from neurons expressing the ionotropic receptor IR94e. High salt avoidance is mediated by ‘bitter’ neurons and a population of glutamatergic neurons expressing Ppk23. Interestingly, the impact of these glutamatergic neurons depends on prior salt consumption. These results support a complex model for salt coding in flies that combinatorially integrates inputs from across cell types to afford robust and flexible salt behaviors. Salt is essential for our survival, but too much can kill us. Our taste system has therefore evolved two different pathways to help us maintain balance. Low concentrations (like the salt on our chips) activate a pathway that makes us want to eat. But high concentrations (like the salt in seawater) activate pathways that do the opposite. The nervous system takes on the role of detecting salt and encoding the information in a way that the brain can use. One specific type of cell detects each of the four other tastes: sweet, bitter, sour, and umami. But salt, with its two sensing pathways, is the exception to this rule. Previous work has examined salt taste responses in flies, but the picture is incomplete. In flies, one type of taste neuron uses a different signaling mechanism to the others, suggesting that it might play a special role. So here, Jaeger, Stanley et al. asked how fly sensory cells encode salt information for the brain, and what those unusual neurons are for. Mapping the taste receptor neurons in the tongue-like structure of the fly, the proboscis, revealed that salt information is not restricted to one or two types of cell. In fact, all five types of neurons tested (covering more than 90% of all the taste neurons present in flies) responded to salt in some way. Of these, two ‘low salt’ cell types made the fly want to eat salt, and two ‘high salt’ cell types made the fly want to avoid it. One of these high salt cell types was the unusual taste neuron identified previously. Rather than always encoding high salt as 'bad', the message from this type of cell changed depending on the diet of the fly. Salt-deprived flies ignored the activity of that cell type altogether. This complex way of encoding taste allowed the fly to change its behavior depending on how much salt it needed. This work opens new questions, like how do the fly's neuronal circuits process this complex salt code? And how do the ‘high salt’ cells achieve their negative effect only when the need for salt is low? Understanding more about this system could lead to a better understanding of why our own brains enjoy salty foods so much.
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Affiliation(s)
- Alexandria H Jaeger
- Department of Zoology, University of British Columbia, Vancouver, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Molly Stanley
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Zachary F Weiss
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Pierre-Yves Musso
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Rachel Cw Chan
- Engineering Physics Program, University of British Columbia, Vancouver, Canada
| | - Han Zhang
- Engineering Physics Program, University of British Columbia, Vancouver, Canada
| | | | - Michael D Gordon
- Department of Zoology, University of British Columbia, Vancouver, Canada
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12
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Zhang P, Lu H, Peixoto RT, Pines MK, Ge Y, Oku S, Siddiqui TJ, Xie Y, Wu W, Archer-Hartmann S, Yoshida K, Tanaka KF, Aricescu AR, Azadi P, Gordon MD, Sabatini BL, Wong ROL, Craig AM. Heparan Sulfate Organizes Neuronal Synapses through Neurexin Partnerships. Cell 2018; 174:1450-1464.e23. [PMID: 30100184 PMCID: PMC6173057 DOI: 10.1016/j.cell.2018.07.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 06/23/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022]
Abstract
Synapses are fundamental units of communication in the brain. The prototypical synapse-organizing complex neurexin-neuroligin mediates synapse development and function and is central to a shared genetic risk pathway in autism and schizophrenia. Neurexin's role in synapse development is thought to be mediated purely by its protein domains, but we reveal a requirement for a rare glycan modification. Mice lacking heparan sulfate (HS) on neurexin-1 show reduced survival, as well as structural and functional deficits at central synapses. HS directly binds postsynaptic partners neuroligins and LRRTMs, revealing a dual binding mode involving intrinsic glycan and protein domains for canonical synapse-organizing complexes. Neurexin HS chains also bind novel ligands, potentially expanding the neurexin interactome to hundreds of HS-binding proteins. Because HS structure is heterogeneous, our findings indicate an additional dimension to neurexin diversity, provide a molecular basis for fine-tuning synaptic function, and open therapeutic directions targeting glycan-binding motifs critical for brain development.
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Affiliation(s)
- Peng Zhang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
| | - Hong Lu
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Rui T Peixoto
- Howard Hughes Medical Institute, Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA; Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Mary K Pines
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Shinichiro Oku
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Tabrez J Siddiqui
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yicheng Xie
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Wenlan Wu
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada; Medical School, Henan University of Science and Technology, Luoyang 471023, China
| | | | - Keitaro Yoshida
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - A Radu Aricescu
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Bernardo L Sabatini
- Howard Hughes Medical Institute, Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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13
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LeDue EE, Chen YC, Jung AY, Dahanukar A, Gordon MD. Pharyngeal sense organs drive robust sugar consumption in Drosophila. Nat Commun 2015; 6:6667. [PMID: 25807033 PMCID: PMC4375776 DOI: 10.1038/ncomms7667] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 02/18/2015] [Indexed: 11/30/2022] Open
Abstract
The fly pharyngeal sense organs lie at the transition between external and internal nutrient sensing mechanisms. Here, we investigate the function of pharyngeal sweet gustatory receptor neurons (GRNs), demonstrating that they express a subset of the nine previously identified sweet receptors and respond to stimulation with a panel of sweet compounds. We show that pox-neuro (poxn) mutants lacking taste function in the legs and labial palps have intact pharyngeal sweet taste, which is both necessary and sufficient to drive preferred consumption of sweet compounds by prolonging ingestion. Moreover, flies putatively lacking all sweet taste show little preference for nutritive or non-nutritive sugars in a short-term feeding assay. Together, our data demonstrate that pharyngeal sense organs play an important role in directing sustained consumption of sweet compounds, and suggest that post-ingestive sugar sensing does not effectively drive food choice in a simple short-term feeding paradigm.
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Affiliation(s)
- Emily E LeDue
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Yu-Chieh Chen
- Interdepartmental Neuroscience Program, University of California, Riverside, California 92521, USA
| | - Aera Y Jung
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, California 92521, USA.,Department of Entomology, University of California, Riverside, California 92521, USA
| | - Michael D Gordon
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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14
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Pool AH, Kvello P, Mann K, Cheung SK, Gordon MD, Wang L, Scott K. Four GABAergic interneurons impose feeding restraint in Drosophila. Neuron 2014; 83:164-77. [PMID: 24991960 DOI: 10.1016/j.neuron.2014.05.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2014] [Indexed: 10/25/2022]
Abstract
Feeding is dynamically regulated by the palatability of the food source and the physiological needs of the animal. How consumption is controlled by external sensory cues and internal metabolic state remains under intense investigation. Here, we identify four GABAergic interneurons in the Drosophila brain that establish a central feeding threshold which is required to inhibit consumption. Inactivation of these cells results in indiscriminate and excessive intake of all compounds, independent of taste quality or nutritional state. Conversely, acute activation of these neurons suppresses consumption of water and nutrients. The output from these neurons is required to gate activity in motor neurons that control meal initiation and consumption. Thus, our study reveals a layer of inhibitory control in feeding circuits that is required to suppress a latent state of unrestricted and nonselective consumption.
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Affiliation(s)
- Allan-Hermann Pool
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Pal Kvello
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Kevin Mann
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Samantha K Cheung
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Michael D Gordon
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Liming Wang
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA.
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15
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Abstract
The decision to engage in one behavior often precludes the selection of others, suggesting cross-inhibition between incompatible behaviors. For example, the likelihood to initiate feeding might be influenced by an animal's commitment to other behaviors. Here, we examine the modulation of feeding behavior in the fruit fly, Drosophila melanogaster, and identify a pair of interneurons in the ventral nerve cord that is activated by stimulation of mechanosensory neurons and inhibits feeding initiation, suggesting that these neurons suppress feeding while the fly is walking. Conversely, inhibiting activity in these neurons promotes feeding initiation and inhibits locomotion. These studies demonstrate the mutual exclusivity between locomotion and feeding initiation in the fly, isolate interneurons that influence this behavioral choice, and provide a framework for studying the neural basis for behavioral exclusivity in Drosophila.
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Affiliation(s)
- Kevin Mann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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16
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McElwain MA, Ko DC, Gordon MD, Fyrst H, Saba JD, Nusse R. A suppressor/enhancer screen in Drosophila reveals a role for wnt-mediated lipid metabolism in primordial germ cell migration. PLoS One 2011; 6:e26993. [PMID: 22069480 PMCID: PMC3206050 DOI: 10.1371/journal.pone.0026993] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 10/07/2011] [Indexed: 11/18/2022] Open
Abstract
Wnt proteins comprise a large family of secreted ligands implicated in a wide variety of biological roles. WntD has previously been shown to inhibit the nuclear accumulation of Dorsal/NF-κB protein during embryonic dorsal/ventral patterning and the adult innate immune response, independent of the well-studied Armadillo/β-catenin pathway. In this paper, we present a novel phenotype for WntD mutant embryos, suggesting that this gene is involved in migration of primordial germ cells (PGC) to the embryonic gonad. Additionally, we describe a genetic suppressor/enhancer screen aimed at identifying genes required for WntD signal transduction, based on the previous observation that maternal overexpression of WntD results in lethally dorsalized embryos. Using an algorithm to narrow down our hits from the screen, we found two novel WntD signaling components: Fz4, a member of the Frizzled family, and the Drosophila Ceramide Kinase homolog, Dcerk. We show here that Dcerk and Dmulk (Drosophila Multi-substrate lipid kinase) redundantly mediate PGC migration. Our data are consistent with a model in which the activity of lipid phosphate phosphatases shapes a concentration gradient of ceramide-1-phosphate (C1P), the product of Dcerk, allowing proper PGC migration.
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MESH Headings
- Animals
- Animals, Genetically Modified
- Blotting, Southern
- Blotting, Western
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Movement
- Ceramides/metabolism
- Drosophila/genetics
- Drosophila/growth & development
- Drosophila/metabolism
- Drosophila Proteins/genetics
- Drosophila Proteins/metabolism
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/metabolism
- Enhancer Elements, Genetic
- Female
- Genetic Testing
- Germ Cells/physiology
- Immunoprecipitation
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Lipid Metabolism
- Male
- Phylogeny
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Suppression, Genetic
- beta Catenin/metabolism
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Affiliation(s)
- Mark A. McElwain
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Dennis C. Ko
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael D. Gordon
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Henrik Fyrst
- Center for Cancer Research, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Julie D. Saba
- Center for Cancer Research, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Roel Nusse
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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17
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Yang CH, Rumpf S, Xiang Y, Gordon MD, Song W, Jan LY, Jan YN. Control of the postmating behavioral switch in Drosophila females by internal sensory neurons. Neuron 2009; 61:519-26. [PMID: 19249273 DOI: 10.1016/j.neuron.2008.12.021] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 11/25/2008] [Accepted: 12/01/2008] [Indexed: 10/21/2022]
Abstract
Mating induces changes in the receptivity and egg-laying behavior in Drosophila females, primarily due to a peptide pheromone called sex peptide which is transferred with the sperm into the female reproductive tract during copulation. Whereas sex peptide is generally believed to modulate fruitless-GAL4-expressing neurons in the central nervous system to produce behavioral changes, we found that six to eight sensory neurons on the reproductive tract labeled by both ppk-GAL4 and fruitless-GAL4 can sense sex peptide to control the induction of postmating behaviors. In these sensory neurons, sex peptide appears to act through Pertussis toxin-sensitive G proteins and suppression of protein kinase A activity to reduce synaptic output. Our results uncover a neuronal mechanism by which sex peptide exerts its control over reproductive behaviors in Drosophila females.
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Affiliation(s)
- Chung-Hui Yang
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA
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18
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Abstract
Tastes elicit innate behaviors critical for directing animals to ingest nutritious substances and reject toxic compounds, but the neural basis of these behaviors is not understood. Here, we use a neural silencing screen to identify neurons required for a simple Drosophila taste behavior and characterize a neural population that controls a specific subprogram of this behavior. By silencing and activating subsets of the defined cell population, we identify the neurons involved in the taste behavior as a pair of motor neurons located in the subesophageal ganglion (SOG). The motor neurons are activated by sugar stimulation of gustatory neurons and inhibited by bitter compounds; however, experiments utilizing split-GFP detect no direct connections between the motor neurons and primary sensory neurons, indicating that further study will be necessary to elucidate the circuitry bridging these populations. Combined, these results provide a general strategy and a valuable starting point for future taste circuit analysis.
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Affiliation(s)
- Michael D Gordon
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, 291 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720, USA
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19
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Wu H, Gordon MD. From Social Tagging to Social Hierarchies: Sharing Deeper Structural Knowledge in Web 2.0. CAIS 2009. [DOI: 10.17705/1cais.02445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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20
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Gordon MD, Ayres JS, Schneider DS, Nusse R. Pathogenesis of listeria-infected Drosophila wntD mutants is associated with elevated levels of the novel immunity gene edin. PLoS Pathog 2008; 4:e1000111. [PMID: 18654628 PMCID: PMC2453329 DOI: 10.1371/journal.ppat.1000111] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 06/26/2008] [Indexed: 11/19/2022] Open
Abstract
Drosophila melanogaster mount an effective innate immune response against invading microorganisms, but can eventually succumb to persistent pathogenic infections. Understanding of this pathogenesis is limited, but it appears that host factors, induced by microbes, can have a direct cost to the host organism. Mutations in wntD cause susceptibility to Listeria monocytogenes infection, apparently through the derepression of Toll-Dorsal target genes, some of which are deleterious to survival. Here, we use gene expression profiling to identify genes that may mediate the observed susceptibility of wntD mutants to lethal infection. These genes include the TNF family member eiger and the novel immunity gene edin (elevated during infection; synonym CG32185), both of which are more strongly induced by infection of wntD mutants compared to controls. edin is also expressed more highly during infection of wild-type flies with wild-type Salmonella typhimurium than with a less pathogenic mutant strain, and its expression is regulated in part by the Imd pathway. Furthermore, overexpression of edin can induce age-dependent lethality, while loss of function in edin renders flies more susceptible to Listeria infection. These results are consistent with a model in which the regulation of host factors, including edin, must be tightly controlled to avoid the detrimental consequences of having too much or too little activity. Like any organism, fruit flies respond to invading microorganisms by mounting an immune defense. Many aspects of the immune defense in fruit flies are similar to the inflammatory response in mammals, including the harmful effects of a sustained response against persistent pathogenic infections. We found in the past that mutations in the gene wntD cause flies to succumb more easily to Listeria monocytogenes infections, apparently by losing an element of control over the inflammatory response. How does the wntD gene work? In this paper, we have identified genes that may mediate the susceptibility of wntD mutants to lethal infection. These genes include eiger, a homolog of the mammalian TNF gene, and a previously uncharacterized gene called edin (elevated during infection). Edin is expressed excessively in wntD mutant flies, and its expression also correlates with the level of pathogenesis induced by two different strains of Salmonella typhimurium. In its own right, overexpression of the edin gene can induce lethality, while losing edin function renders flies more susceptible to Listeria infection. Our results support a model in which the regulation of host factors, including edin, must be tightly controlled to avoid the detrimental consequences of having too much or too little activity.
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Affiliation(s)
- Michael D. Gordon
- Department of Developmental Biology, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, California, United States of America
| | - Janelle S. Ayres
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - David S. Schneider
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (DSS); (RN)
| | - Roel Nusse
- Department of Developmental Biology, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (DSS); (RN)
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21
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Schneider DS, Ayres JS, Brandt SM, Costa A, Dionne MS, Gordon MD, Mabery EM, Moule MG, Pham LN, Shirasu-Hiza MM. Drosophila eiger mutants are sensitive to extracellular pathogens. PLoS Pathog 2007; 3:e41. [PMID: 17381241 PMCID: PMC1829408 DOI: 10.1371/journal.ppat.0030041] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 02/06/2007] [Indexed: 11/19/2022] Open
Abstract
We showed previously that eiger, the Drosophila tumor necrosis factor homolog, contributes to the pathology induced by infection with Salmonella typhimurium. We were curious whether eiger is always detrimental in the context of infection or if it plays a role in fighting some types of microbes. We challenged wild-type and eiger mutant flies with a collection of facultative intracellular and extracellular pathogens, including a fungus and Gram-positive and Gram-negative bacteria. The response of eiger mutants divided these microbes into two groups: eiger mutants are immunocompromised with respect to extracellular pathogens but show no change or reduced sensitivity to facultative intracellular pathogens. Hence, eiger helps fight infections but also can cause pathology. We propose that eiger activates the cellular immune response of the fly to aid clearance of extracellular pathogens. Intracellular pathogens, which can already defeat professional phagocytes, are unaffected by eiger. We show that the gene eiger, which is the sole tumor necrosis factor homolog in the fruit fly, can play opposing roles in the fly's response to infections. Sometimes eiger contributes to the disease induced by an infection, while at other times it is required to fight an infection. Commonly, the fly's immune response is described as dividing microbes into two groups with Gram-positive bacteria and fungi lying in one group and Gram-negative bacteria lying in the other. Pathogenic bacteria can also be divided into two groups based on their behavior in eiger mutant flies, but these two groups differ from past descriptions. eiger tends to be required for the innate immune response against extracellular pathogens but tends to cause pathology during an infection with an intracellular pathogen. We suggest that eiger is required for innate immune responses that are effective at fighting extracellular pathogens but are wasteful or simply ineffective when fighting intracellular pathogens. We show here that the fly immune response is more complex than previously recognized and suggest new directions for studying pathogenesis in addition to innate immunity in the fly.
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Affiliation(s)
- David S Schneider
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America.
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22
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Avital M, Lyytinen KJ, King JL, Gordon MD, Granger-Happ E, Mason RO, Watson RT. Leveraging Information Technology to Support Agents of World Benefit. CAIS 2007. [DOI: 10.17705/1cais.01925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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23
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Affiliation(s)
- Michael D Gordon
- Howard Hughes Medical Institute and Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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24
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Gordon MD, Dionne MS, Schneider DS, Nusse R. WntD is a feedback inhibitor of Dorsal/NF-kappaB in Drosophila development and immunity. Nature 2005; 437:746-9. [PMID: 16107793 PMCID: PMC1256032 DOI: 10.1038/nature04073] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2005] [Accepted: 07/20/2005] [Indexed: 11/10/2022]
Abstract
Regulating the nuclear factor-kappaB (NF-kappaB) family of transcription factors is of critical importance to animals, with consequences of misregulation that include cancer, chronic inflammatory diseases and developmental defects. Studies in Drosophila melanogaster have proved fruitful in determining the signals used to control NF-kappaB proteins, beginning with the discovery that the Toll/NF-kappaB pathway, in addition to patterning the dorsal-ventral axis of the fly embryo, defines a major component of the innate immune response in both Drosophila and mammals. Here, we characterize the Drosophila wntD (Wnt inhibitor of Dorsal) gene. We show that WntD acts as a feedback inhibitor of the NF-kappaB homologue Dorsal during both embryonic patterning and the innate immune response to infection. wntD expression is under the control of Toll/Dorsal signalling, and increased levels of WntD block Dorsal nuclear accumulation, even in the absence of the IkappaB homologue Cactus. The WntD signal is independent of the common Wnt signalling component Armadillo (beta-catenin). By engineering a gene knockout, we show that wntD loss-of-function mutants have immune defects and exhibit increased levels of Toll/Dorsal signalling. Furthermore, the wntD mutant phenotype is suppressed by loss of zygotic dorsal. These results describe the first secreted feedback antagonist of Toll signalling, and demonstrate a novel Wnt activity in the fly.
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Affiliation(s)
- Michael D Gordon
- Department of Developmental Biology, Howard Hughes Medical Institute, Beckman Center and
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25
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26
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Settle M, Gordon MD, Nadella M, Dankort D, Muller W, Jacobs JR. Genetic identification of effectors downstream of Neu (ErbB-2) autophosphorylation sites in a Drosophila model. Oncogene 2003; 22:1916-26. [PMID: 12673197 DOI: 10.1038/sj.onc.1206240] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ErbB-2/Neu receptor tyrosine kinase plays a causal role in tumorigenesis in mammals. Neu's carboxyl terminus contains five phosphorylated tyrosines that mediate transformation through interaction with cytoplasmic SH2 or PTB containing adaptor proteins. We show that Drosophila adaptors signal from individual phosphotyrosine sites of rat Neu. Activated Neu expression in the midline glia suppressed apoptosis, similar to that seen with activated Drosophila EGF-R expression. Expression in eye and wing tissues generated graded phenotypes suitable for dosage-sensitive modifier genetics. Suppression of ErbB-2/Neu-induced phenotypes in tissues haplosufficient for genes encoding adaptor protein or second messengers suggests that pTyr 1227(YD) signals require Shc, and that pTyr 1253 (YE) signalling does not employ Ras, but does require Raf function. Signalling from pTyr (YB) was affected by a haplosufficiency in drk (Grb-2), and in genes thought to function downstream of Grb-2: dab, sos, csw (Shp-2), and dos (Gab-1). These data demonstrate the power of Drosophila genetics to unmask the molecules that signal from oncogenic ErbB-2/Neu.
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MESH Headings
- Adaptor Proteins, Vesicular Transport
- Animals
- Animals, Genetically Modified
- Apoptosis/genetics
- Apoptosis/physiology
- Drosophila Proteins/genetics
- Drosophila Proteins/physiology
- Drosophila melanogaster/embryology
- Drosophila melanogaster/genetics
- Drosophila melanogaster/growth & development
- Drosophila melanogaster/metabolism
- ErbB Receptors/physiology
- Eye/growth & development
- Eye Proteins/genetics
- Eye Proteins/physiology
- Gene Dosage
- Gene Expression Regulation, Developmental
- Morphogenesis/genetics
- Morphogenesis/physiology
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/physiology
- Phenotype
- Phosphorylation
- Phosphotyrosine/chemistry
- Protein Kinases
- Protein Processing, Post-Translational
- Protein Structure, Tertiary
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/physiology
- Protein Tyrosine Phosphatases, Non-Receptor
- Proteins/genetics
- Proteins/physiology
- Proto-Oncogene Proteins c-raf/genetics
- Proto-Oncogene Proteins c-raf/physiology
- Rats
- Receptor, ErbB-2/chemistry
- Receptor, ErbB-2/physiology
- Receptors, Invertebrate Peptide/physiology
- Recombinant Fusion Proteins/physiology
- Shc Signaling Adaptor Proteins
- Signal Transduction/genetics
- Signal Transduction/physiology
- Son of Sevenless Protein, Drosophila/genetics
- Son of Sevenless Protein, Drosophila/physiology
- Structure-Activity Relationship
- Wings, Animal/growth & development
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Affiliation(s)
- Mark Settle
- Department of Biology, McMaster University, Hamilton, ON, Canada
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27
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Albright TA, Gordon MD, Freeman WJ, Schweizer EE. Nuclear magnetic resonance studies. 5. Properties of phosphorus-carbon ylides. J Am Chem Soc 2002. [DOI: 10.1021/ja00436a030] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Gordon MD, Quin LD. Carbon-13 nuclear magnetic resonance spectroscopy in the study of conformational effects among cyclohexyl phosphorus compounds. J Org Chem 2002. [DOI: 10.1021/jo00872a004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Gordon MD, Alston PV, Rossi AR. The role of primary-secondary orbital interactions in affecting regioselectivities. Cycloaddition reactions between 1,3-dipoles and electron-deficient alkynes. J Am Chem Soc 2002. [DOI: 10.1021/ja00486a019] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Gordon MD, Quin LD. Phosphorus-31 nuclear magnetic resonance spectroscopy in the determination of conformational free energies of phosphorus groups on the cyclohexane ring. J Am Chem Soc 2002. [DOI: 10.1021/ja00417a004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Alston PV, Gordon MD, Ottenbrite RM, Cohen T. Secondary orbital interactions determining regioselectivity in the Diels-Alder reaction. 5. Thio-substituted 1,3-butadienes. J Org Chem 2002. [DOI: 10.1021/jo00173a051] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Gordon MD, Fukunaga T, Simmons HE. A quantitative treatment of spiroconjugation. Long-range "through-space" interactions and chemical reactivity of spirenes. J Am Chem Soc 2002. [DOI: 10.1021/ja00442a015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Gordon MD, Neumer JF. CNDO [complete neglect of differential overlap] and ab initio derived .sigma.-core charges for Pariser-Parr-Pople .pi.-electron calculations on nitroaromatics. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100611a020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ko DC, Gordon MD, Jin JY, Scott MP. Dynamic movements of organelles containing Niemann-Pick C1 protein: NPC1 involvement in late endocytic events. Mol Biol Cell 2001; 12:601-14. [PMID: 11251074 PMCID: PMC30967 DOI: 10.1091/mbc.12.3.601] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
People homozygous for mutations in the Niemann-Pick type C1 (NPC1) gene have physiological defects, including excess accumulation of intracellular cholesterol and other lipids, that lead to drastic neural and liver degeneration. The NPC1 multipass transmembrane protein is resident in late endosomes and lysosomes, but its functions are unknown. We find that organelles containing functional NPC1-fluorescent protein fusions undergo dramatic movements, some in association with extending strands of endoplasmic reticulum. In NPC1 mutant cells the NPC1-bearing organelles that normally move at high speed between perinuclear regions and the periphery of the cell are largely absent. Pulse-chase experiments with dialkylindocarbocyanine low-density lipoprotein showed that NPC1 organelles function late in the endocytic pathway; NPC1 protein may aid the partitioning of endocytic and lysosomal compartments. The close connection between NPC1 and the drug U18666A, which causes NPC1-like organelle defects, was established by rescuing drug-treated cells with overproduced NPC1. U18666A inhibits outward movements of NPC1 organelles, trapping membranes and cholesterol in perinuclear organelles similar to those in NPC1 mutant cells, even when cells are grown in lipoprotein-depleted serum. We conclude that NPC1 protein promotes the creation and/or movement of particular late endosomes, which rapidly transport materials to and from the cell periphery.
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Affiliation(s)
- D C Ko
- Departments of Developmental Biology and Genetics, Howard Hughes Medical Institute, Beckman Center B300, Stanford University School of Medicine, Stanford, California 94305, USA
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Abstract
The Drosophila epidermal growth factor receptor (EGFR) may be activated by two ligands expressed in the embryonic nervous system, Spitz and Vein. Previous studies have established Spitz as an essential activator of EGFR signaling in nervous system development. Here, we report the pattern of expression of vein mRNA in the nervous system and characterize the contribution of vein to cell lineage and axonogenesis. The number of midline glia (MG) precursors is reduced in vein mutants before the onset of embryonic apoptosis. In contrast to spitz, mis-expression of vein does not suppress apoptosis in the MG. These data indicate that early midline EGFR signaling, requiring vein and spitz, establishes MG precursor number, whereas later EGFR signals, requiring spitz, suppress apoptosis in the MG. vein mutants show early irregularities during axon tract establishment, which resolve later to variable defasciculation and thinner intersegmental axon tracts. vein and spitz phenotypes act additively in the regulation of MG cell number, but show synergism in a midline neuronal cell number phenotype and in axon tract architecture. vein appears to act downstream of spitz to briefly amplify local EGFR activation.Key words: Drosophila, vein, midline, axonogenesis, EGF receptor, lineage, neuregulin, spitz, CNS.
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Lanoue BR, Gordon MD, Battye R, Jacobs JR. Genetic analysis of vein function in the Drosophila embryonic nervous system. Genome 2000; 43:564-73. [PMID: 10902722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The Drosophila epidermal growth factor receptor (EGFR) may be activated by two ligands expressed in the embryonic nervous system, Spitz and Vein. Previous studies have established Spitz as an essential activator of EGFR signaling in nervous system development. Here, we report the pattern of expression of vein mRNA in the nervous system and characterize the contribution of vein to cell lineage and axonogenesis. The number of midline glia (MG) precursors is reduced in vein mutants before the onset of embryonic apoptosis. In contrast to spitz, mis-expression of vein does not suppress apoptosis in the MG. These data indicate that early midline EGFR signaling, requiring vein and spitz, establishes MG precursor number, whereas later EGFR signals, requiring spitz, suppress apoptosis in the MG. vein mutants show early irregularities during axon tract establishment, which resolve later to variable defasciculation and thinner intersegmental axon tracts. vein and spitz phenotypes act additively in the regulation of MG cell number, but show synergism in a midline neuronal cell number phenotype and in axon tract architecture. vein appears to act downstream of spitz to briefly amplify local EGFR activation.
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Affiliation(s)
- B R Lanoue
- Department of Biology, McMaster University, Hamilton, ON, Canada
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Gordon MD, Corless C, Renshaw AA, Beckstead J. CD99, keratin, and vimentin staining of sex cord-stromal tumors, normal ovary, and testis. Mod Pathol 1998; 11:769-73. [PMID: 9720506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
CD99, a marker for MIC-2, reacts with normal Sertoli cells and granulosa cells. We investigated CD99 expression in the development of normal ovary and testis as well as in 25 sex cord-stromal tumors (SCSTs), 7 epithelial neoplasms, and 6 germ cell tumors. Normal Sertoli cells and mature granulosa cells showed 3+ staining with CD99. Pregranulosa cells of primordial follicles were negative. All of the eight Sertoli-Leydig cell tumors were positive with antibody to CD99, with the well-differentiated tumors showing the greatest degree of staining intensity. Reactivity of 2+ to 3+ with CD99 was observed in all of the 11 granulosa cell tumors and in yolk sac components of the germ cell tumors investigated. All of the poorly differentiated carcinomas were negative with CD99. We concluded that CD99 might be a useful marker for SCSTs and that its degree of reactivity correlates with the degree of differentiation in Sertoli-Leydig cell tumors. Additionally, CD99 might aid in distinguishing granulosa cell tumors of the ovary from poorly differentiated carcinomas.
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Affiliation(s)
- M D Gordon
- Department of Pathology, Oregon Health Sciences University, Portland 97201, USA
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Abstract
Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas that almost always arise in soft tissue. They can develop in pre-existing neurofibromas or schwannomas, de novo from peripheral nerves, or following radiation therapy. Primary intraosseous MPNST is rare and has been reported most frequently in the mandible. Of the reported cases involving the long bones, none has been associated with neurofibromatosis type 1 (NF-1). We report a case of MPNST arising in the femur in a patient with NF-1.
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Affiliation(s)
- D G Terry
- VA Medical Center, Imaging Service, Portland, OR 97201, USA
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Neumer JF, Gordon MD, McEwen CN, Peacock PM, Hill SA, McKay RG, Lazar J, Valentine JR, Van Lenten FJ, Foris A. New polyazaporphine chemistry for the origin of life. ORIGINS LIFE EVOL B 1998; 28:27-45. [PMID: 11536854 DOI: 10.1023/a:1006561310605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Molecular orbital spectral predictions suggest that 2,5,7,10,12,15,17,20-octaaza-21H, 23H-porphine has a visible spectral range closely matching that of chlorophyll-a. Since the octaazaporphine is, in its core, a simple derivative of an (HCN)12 oligomer, this fact, together with its spectral properties, would suggest that it occupies a high rank as a primordial porphinic solar energy transducer for photochemistry essential to life's formation. The demonstration that the mass 324 hexahydrooctaazaporphine is formed in protic media by the cyclotetramerization of imidazol-4-aminohydroxonium ion or the derived nitrenium ion, and that a mass 318 species consonant with that of the Huckel aromatic octaazaporphine is observed in the course of these studies, strongly supports the proposed octaazaporphine synthesis in a prebiotic hydrocyanic acid milieu.
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Affiliation(s)
- J F Neumer
- E.I. Du Pont de Nemours & Co., Inc., Wilmington, Delaware 19898, USA
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Abstract
A 66-year-old man presented with severe chronic dysphagia and weight loss. A barium esophagogram revealed a proximal esophageal stricture and multiple pseudodiverticula. After death from aspiration pneumonia, a postmortem examination revealed extensive esophageal pseudodiverticulosis. Clinical presentation, pathogenesis, diagnosis, and management of this unusual disorder are reviewed.
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Affiliation(s)
- K D Flora
- Department of Gastroenterology, Oregon Health Sciences University, Portland Veterans Affairs Medical Center 97201, USA
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Abstract
BACKGROUND Neurofibromatosis involving the female genital tract is unusual. The vulva appears to be most frequently affected, with only rare reports of vaginal, cervical, and ovarian involvement in patients with known von Recklinghausen's disease. CASE We present a case of diffuse neurofibromatosis involving the cervix, endometrium, myometrium, ovarian cortex, and serosa in a patient with uncontrollable pelvic pain, diagnosed initially as endometriosis. No gross pathology was appreciated, and the histologic features of the small lesions were consistent with plexiform neurofibromas. CONCLUSION The case presented is an example of diffuse involvement of the female genital tract by neurofibromatosis in a patient without a family history of von Recklinghausen's disease and without other clinical manifestations of the disease.
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Affiliation(s)
- M D Gordon
- Department of Pathology, Oregon Health Sciences University, Portland, USA
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Gordon MD, Lindsay RK. Toward discovery support systems: A replication, re-examination, and extension of Swanson's work on literature-based discovery of a connection between Raynaud's and fish oil. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/(sici)1097-4571(199602)47:2<116::aid-asi3>3.0.co;2-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gordon MD, Ireland K. New developments in sex cord-stromal and germ cell tumors of the ovary. Clin Lab Med 1995; 15:595-610. [PMID: 8542725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This article examines unusual and recently described neoplasms such as variants of Sertoli-Leydig cell tumors, monodermal teratomas, and small cell carcinoma, both the hypercalcemic and pulmonic types. Additionally, clues to assist in differentiating metastatic from primary tumors of the ovary are discussed.
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Affiliation(s)
- M D Gordon
- Department of Pathology, Oregon Health Sciences University, Portland, USA
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