1
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Banerjee N, Gang SS, Castelletto ML, Walsh B, Ruiz F, Hallem EA. Carbon dioxide shapes parasite-host interactions in a human-infective nematode. Curr Biol 2025; 35:277-286.e6. [PMID: 39719698 PMCID: PMC11753939 DOI: 10.1016/j.cub.2024.11.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 10/29/2024] [Accepted: 11/18/2024] [Indexed: 12/26/2024]
Abstract
Skin-penetrating nematodes infect nearly one billion people worldwide. The developmentally arrested infective larvae (iL3s) seek out hosts, invade hosts via skin penetration, and resume development inside the host in a process called activation. Activated infective larvae (iL3as) traverse the host body, ending up as parasitic adults in the small intestine. Skin-penetrating nematodes respond to many chemosensory cues, but how chemosensation contributes to host seeking and intra-host navigation-two crucial steps of the parasite-host interaction-remains poorly understood. Here, we investigate the role of carbon dioxide (CO2) in promoting host seeking and intra-host navigation in the human-infective threadworm Strongyloides stercoralis. We show that S. stercoralis exhibits life-stage-specific behavioral preferences for CO2: iL3s are repelled, non-infective larvae and adults are neutral, and iL3as are attracted. CO2 repulsion in iL3s may prime them for host seeking by stimulating dispersal from host feces, while CO2 attraction in iL3as may direct worms toward high-CO2 areas of the body, such as the lungs and intestine. We also identify sensory neurons that detect CO2; these neurons display CO2-evoked calcium activity, promote behavioral responses to CO2, and express the receptor guanylate cyclase Ss-GCY-9. Finally, we develop an approach for generating stable knockout lines in S. stercoralis and use this approach to show that Ss-gcy-9 is required for CO2-evoked behavioral responses in both iL3s and iL3as. Our results highlight chemosensory mechanisms that shape the interaction between parasitic nematodes and their human hosts and may aid in the design of novel anthelmintics that target the CO2-sensing pathway.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Spencer S Gang
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michelle L Castelletto
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Breanna Walsh
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Interdepartmental PhD Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; UCLA-Caltech Medical Scientist Training Program, University of California, Los Angeles, Los Angeles, CA, USA
| | - Felicitas Ruiz
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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2
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Broillet-Olivier E, Wenger Y, Gilliand N, Cadas H, Sabatasso S, Broillet MC, Brechbühl J. Development of an rpS6-Based Ex Vivo Assay for the Analysis of Neuronal Activity in Mouse and Human Olfactory Systems. Int J Mol Sci 2024; 25:13173. [PMID: 39684883 DOI: 10.3390/ijms252313173] [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: 10/22/2024] [Revised: 11/27/2024] [Accepted: 12/04/2024] [Indexed: 12/18/2024] Open
Abstract
Olfactory sensitivity to odorant molecules is a complex biological function influenced by both endogenous factors, such as genetic background and physiological state, and exogenous factors, such as environmental conditions. In animals, this vital ability is mediated by olfactory sensory neurons (OSNs), which are distributed across several specialized olfactory subsystems depending on the species. Using the phosphorylation of the ribosomal protein S6 (rpS6) in OSNs following sensory stimulation, we developed an ex vivo assay allowing the simultaneous conditioning and odorant stimulation of different mouse olfactory subsystems, including the main olfactory epithelium, the vomeronasal organ, and the Grueneberg ganglion. This approach enabled us to observe odorant-induced neuronal activity within the different olfactory subsystems and to demonstrate the impact of environmental conditioning, such as temperature variations, on olfactory sensitivity, specifically in the Grueneberg ganglion. We further applied our rpS6-based assay to the human olfactory system and demonstrated its feasibility. Our findings show that analyzing rpS6 signal intensity is a robust and highly reproducible indicator of neuronal activity across various olfactory systems, while avoiding stress and some experimental limitations associated with in vivo exposure. The potential extension of this assay to other conditioning paradigms and olfactory systems, as well as its application to other animal species, including human olfactory diagnostics, is also discussed.
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Affiliation(s)
- Emma Broillet-Olivier
- Faculty of Medicine Hradec Králové, Charles University, 500 00 Hradec Králové, Czech Republic
| | - Yaëlle Wenger
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Bugnon 27, CH-1011 Lausanne, Switzerland
| | - Noah Gilliand
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Bugnon 27, CH-1011 Lausanne, Switzerland
| | - Hugues Cadas
- Faculty of Biology and Medicine, University of Lausanne, Bugnon 9, CH-1005 Lausanne, Switzerland
- Faculty Unit of Anatomy and Morphology, University Center of Legal Medicine Lausanne-Geneva, Lausanne University Hospital and University of Lausanne, Vulliette 4, CH-1000 Lausanne, Switzerland
| | - Sara Sabatasso
- Faculty of Biology and Medicine, University of Lausanne, Bugnon 9, CH-1005 Lausanne, Switzerland
- Faculty Unit of Anatomy and Morphology, University Center of Legal Medicine Lausanne-Geneva, Lausanne University Hospital and University of Lausanne, Vulliette 4, CH-1000 Lausanne, Switzerland
| | - Marie-Christine Broillet
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Bugnon 27, CH-1011 Lausanne, Switzerland
| | - Julien Brechbühl
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Bugnon 27, CH-1011 Lausanne, Switzerland
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3
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Cochran JK, Buchwalter DB. The mayfly Neocloeon triangulifer senses decreasing oxygen availability (PO2) and responds by reducing ion uptake and altering gene expression. J Exp Biol 2024; 227:jeb247916. [PMID: 39422090 PMCID: PMC11634025 DOI: 10.1242/jeb.247916] [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: 04/19/2024] [Accepted: 10/08/2024] [Indexed: 10/19/2024]
Abstract
Oxygen availability is central to the energetic budget of aquatic animals and may vary naturally and/or in response to anthropogenic activities. Yet, we know little about how oxygen availability is linked to fundamental processes such as ion transport in aquatic insects. We hypothesized and observed that ion (22Na and 35SO4) uptake would be significantly decreased at O2 partial pressures below the mean critical level (Pcrit, 5.4 kPa) where metabolic rate (ṀO2) is compromised and ATP production is limited. However, we were surprised to observe marked reductions in ion uptake at oxygen partial pressures well above Pcrit, where ṀO2 was stable. For example, SO4 uptake decreased by 51% at 11.7 kPa and 82% at Pcrit (5.4 kPa) while Na uptake decreased by 19% at 11.7 kPa and 60% at Pcrit. Nymphs held for longer time periods at reduced PO2 exhibited stronger reductions in ion uptake rates. Fluids from whole-body homogenates exhibited a 29% decrease in osmolality in the most hypoxic condition. The differential expression of atypical guanylate cyclase (gcy-88e) in response to changing PO2 conditions provides evidence for its potential role as an oxygen sensor. Several ion transport genes (e.g. chloride channel and sodium-potassium ATPase) and hypoxia-associated genes (e.g. ldh and egl-9) were also impacted by decreased oxygen availability. Together, the results of our work suggest that N. triangulifer can sense decreased oxygen availability and perhaps conserves energy accordingly, even when ṀO2 is not impacted.
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Affiliation(s)
- Jamie K. Cochran
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - David B. Buchwalter
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
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4
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Poncelet G, Parolini L, Shimeld SM. A microfluidic chip for immobilization and imaging of Ciona intestinalis larvae. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:443-452. [PMID: 38847208 DOI: 10.1002/jez.b.23267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 04/17/2024] [Accepted: 05/21/2024] [Indexed: 10/05/2024]
Abstract
Sea squirts (Tunicata) are chordates and develop a swimming larva with a small and defined number of individually identifiable cells. This offers the prospect of connecting specific stimuli to behavioral output and characterizing the neural activity that links these together. Here, we describe the development of a microfluidic chip that allows live larvae of the sea squirt Ciona intestinalis to be immobilized and recorded. By generating transgenic larvae expressing GCaAMP6m in defined cells, we show that calcium ion levels can be recorded from immobilized larvae, while microfluidic control allows larvae to be exposed to specific waterborne stimuli. We trial this on sea water carrying increased levels of carbon dioxide, providing evidence that larvae can sense this gas.
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Affiliation(s)
| | - Lucia Parolini
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine and Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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5
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Pan YK, Perry SF. Developing zebrafish utilize taste-signaling pathways for oxygen chemoreception. Curr Biol 2024; 34:4272-4284.e5. [PMID: 39260364 DOI: 10.1016/j.cub.2024.08.015] [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: 11/07/2023] [Revised: 05/29/2024] [Accepted: 08/13/2024] [Indexed: 09/13/2024]
Abstract
A fundamental requirement for all animals is to sense and respond to changes in environmental O2 availability. Low O2 (hypoxia) typically stimulates breathing, a universal and critical response termed the hypoxic ventilatory response (HVR). In this study, we test the hypothesis that taste-signaling pathways are used for O2 sensing and activation of the HVR. We show that Merkel-like cells (MLCs), which are part of the taste-bud complex, function as O2 chemoreceptor cells in larval zebrafish and that transduction of the O2 signal uses taste-signaling pathways. Specifically, MLCs responded to hypoxia in vivo with an increase in Ca2+ activity that can drive the HVR. In addition, MLCs transmit O2 signals to afferent cranial nerves IX and X (nIX/X), which project into the area postrema within the hindbrain and synapse with interneurons that are in contact with vagal motor neurons. Hypoxia or chemo-activation of nIX/X caused Ca2+ activity to increase within the area postrema and elicited hyperventilation. The results provide the first demonstration of an O2 signaling pathway that commences with the activation of taste receptors (MLCs) to yield a critical physiological reflex, the HVR.
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Affiliation(s)
- Yihang Kevin Pan
- University of Ottawa, Department of Biology, 10 Marie-Curie Private, Ottawa, ON K1N 9A4, Canada.
| | - Steve F Perry
- University of Ottawa, Department of Biology, 10 Marie-Curie Private, Ottawa, ON K1N 9A4, Canada.
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6
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Banerjee N, Gang SS, Castelletto ML, Ruiz F, Hallem EA. Carbon dioxide shapes parasite-host interactions in a human-infective nematode. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587273. [PMID: 38585813 PMCID: PMC10996684 DOI: 10.1101/2024.03.28.587273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Skin-penetrating nematodes infect nearly one billion people worldwide. The developmentally arrested infective larvae (iL3s) seek out hosts, invade hosts via skin penetration, and resume development inside the host in a process called activation. Activated infective larvae (iL3as) traverse the host body, ending up as parasitic adults in the small intestine. Skin-penetrating nematodes respond to many chemosensory cues, but how chemosensation contributes to host seeking, intra-host development, and intra-host navigation - three crucial steps of the parasite-host interaction - remains poorly understood. Here, we investigate the role of carbon dioxide (CO2) in promoting parasite-host interactions in the human-infective threadworm Strongyloides stercoralis. We show that S. stercoralis exhibits life-stage-specific preferences for CO2: iL3s are repelled, non-infective larvae and adults are neutral, and iL3as are attracted. CO2 repulsion in iL3s may prime them for host seeking by stimulating dispersal from host feces, while CO2 attraction in iL3as may direct worms toward high-CO2 areas of the body such as the lungs and intestine. We also identify sensory neurons that detect CO2; these neurons are depolarized by CO2 in iL3s and iL3as. In addition, we demonstrate that the receptor guanylate cyclase Ss-GCY-9 is expressed specifically in CO2-sensing neurons and is required for CO2-evoked behavior. Ss-GCY-9 also promotes activation, indicating that a single receptor can mediate both behavioral and physiological responses to CO2. Our results illuminate chemosensory mechanisms that shape the interaction between parasitic nematodes and their human hosts and may aid in the design of novel anthelmintics that target the CO2-sensing pathway.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Spencer S. Gang
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Michelle L. Castelletto
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Felicitas Ruiz
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Elissa A. Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
- Lead contact
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7
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Margherita M, Gianmarco A, Anna M, Roberto F, Serena F, Milena P, Isabella T, Fabio M, Andrea B. Using ethanol as postharvest treatment to increase polyphenols and anthocyanins in wine grape. Heliyon 2024; 10:e26067. [PMID: 38370263 PMCID: PMC10869903 DOI: 10.1016/j.heliyon.2024.e26067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/13/2024] [Accepted: 02/07/2024] [Indexed: 02/20/2024] Open
Abstract
Red wine grapes are qualitatively evaluated for their content in polyphenols and anthocyanins. Due to certain conditions (weather, latitude, temperature), the concentration of these compounds may be not at the right level for reaching a high-quality wine, thus postharvest technologies can be operated as a remediation strategy. Ethanol is a secondary volatile metabolite and its application has been demonstrated to delay fruit ripening, to reduce decay, and to increase secondary metabolites. The present study investigates the effects of ethanol post-harvest application on wine grapes' metabolism and composition. Red wine grapes (Vitis Vinifera L. cv Aglianico) were exposed to different ethanol doses (0.25, 0.5, or 1 mL L-1) for 12, 24, or 36 h. Ethanol increased sugar concentration, malic acid, free amino nitrogen, polyphenols, and anthocyanins. Particularly, anthocyanins reached an average value of 1820 mg/L in treated samples versus the 1200 mg/L of control grapes already after 12 h whatever the concentration was. Moreover, the highest concentration of ethanol modified berry metabolism shifting from aerobic to anaerobic one. Obtained results suggest that 12 h of ethanol postharvest treatment could be an interesting solution to improve anthocyanins in wine grapes, especially when the quality is not as good as expected.
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Affiliation(s)
- Modesti Margherita
- Department for Innovation of Biological, Agrofood and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Alfieri Gianmarco
- Department for Innovation of Biological, Agrofood and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Magri Anna
- CREA - Research Centre for Olive, Fruit and Citrus Crops (CREA-OFA), Caserta, Italy
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania Luigi Vanvitelli, Caserta, Italy
| | - Forniti Roberto
- Department for Innovation of Biological, Agrofood and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Ferri Serena
- Department for Innovation of Biological, Agrofood and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Petriccione Milena
- CREA - Research Centre for Olive, Fruit and Citrus Crops (CREA-OFA), Caserta, Italy
| | - Taglieri Isabella
- Department of Agriculture Food and Environment (DAFE), University of Pisa, Pisa, Italy
| | - Mencarelli Fabio
- Department of Agriculture Food and Environment (DAFE), University of Pisa, Pisa, Italy
| | - Bellincontro Andrea
- Department for Innovation of Biological, Agrofood and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
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8
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Banerjee N, Rojas Palato EJ, Shih PY, Sternberg PW, Hallem EA. Distinct neurogenetic mechanisms establish the same chemosensory valence state at different life stages in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2024; 14:jkad271. [PMID: 38092065 PMCID: PMC10849362 DOI: 10.1093/g3journal/jkad271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/17/2023] [Indexed: 02/09/2024]
Abstract
An animal's preference for many chemosensory cues remains constant despite dramatic changes in the animal's internal state. The mechanisms that maintain chemosensory preference across different physiological contexts remain poorly understood. We previously showed that distinct patterns of neural activity and motor output are evoked by carbon dioxide (CO2) in starved adults vs dauers of Caenorhabditis elegans, despite the two life stages displaying the same preference (attraction) for CO2. However, how the distinct CO2-evoked neural dynamics and motor patterns contribute to CO2 attraction at the two life stages remained unclear. Here, using a CO2 chemotaxis assay, we show that different interneurons are employed to drive CO2 attraction at the two life stages. We also investigate the molecular mechanisms that mediate CO2 attraction in dauers vs adults. We show that insulin signaling promotes CO2 attraction in dauers but not starved adults and that different combinations of neurotransmitters and neuropeptides are used for CO2 attraction at the two life stages. Our findings provide new insight into the distinct molecular and cellular mechanisms used by C. elegans at two different life stages to generate attractive behavioral responses to CO2.
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Affiliation(s)
- Navonil Banerjee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Elisa J Rojas Palato
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Pei-Yin Shih
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Ecology, Evolution and Environmental Biology, Columbia University, NewYork, NY 10027, USA
- Zuckerman Mind, Brain, Behavior Institute, Columbia University, NewYork, NY 10027, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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9
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Galassi L, Facchinetti F. Carbonation and Sweet Taste Dysgeusia with Topiramate Therapy for Migraine Prevention Treatment: a Case Report. SN COMPREHENSIVE CLINICAL MEDICINE 2023; 5:123. [DOI: 10.1007/s42399-023-01467-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/14/2023] [Indexed: 01/05/2025]
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10
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Schwartz M, Boichot V, Fraichard S, Muradova M, Senet P, Nicolai A, Lirussi F, Bas M, Canon F, Heydel JM, Neiers F. Role of Insect and Mammal Glutathione Transferases in Chemoperception. Biomolecules 2023; 13:biom13020322. [PMID: 36830691 PMCID: PMC9953322 DOI: 10.3390/biom13020322] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Glutathione transferases (GSTs) are ubiquitous key enzymes with different activities as transferases or isomerases. As key detoxifying enzymes, GSTs are expressed in the chemosensory organs. They fulfill an essential protective role because the chemosensory organs are located in the main entry paths of exogenous compounds within the body. In addition to this protective function, they modulate the perception process by metabolizing exogenous molecules, including tastants and odorants. Chemosensory detection involves the interaction of chemosensory molecules with receptors. GST contributes to signal termination by metabolizing these molecules. By reducing the concentration of chemosensory molecules before receptor binding, GST modulates receptor activation and, therefore, the perception of these molecules. The balance of chemoperception by GSTs has been shown in insects as well as in mammals, although their chemosensory systems are not evolutionarily connected. This review will provide knowledge supporting the involvement of GSTs in chemoperception, describing their localization in these systems as well as their enzymatic capacity toward odorants, sapid molecules, and pheromones in insects and mammals. Their different roles in chemosensory organs will be discussed in light of the evolutionary advantage of the coupling of the detoxification system and chemosensory system through GSTs.
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Affiliation(s)
- Mathieu Schwartz
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Valentin Boichot
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Stéphane Fraichard
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Mariam Muradova
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Patrick Senet
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Université de Bourgogne Franche-Comté, 21078 Dijon, France
| | - Adrien Nicolai
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Université de Bourgogne Franche-Comté, 21078 Dijon, France
| | - Frederic Lirussi
- UMR 1231, Lipides Nutrition Cancer, INSERM, 21000 Dijon, France
- UFR des Sciences de Santé, Université de Bourgogne Franche-Comté, 25000 Besançon, France
- Plateforme PACE, Laboratoire de Pharmacologie-Toxicologie, Centre Hospitalo-Universitaire Besançon, 25000 Besançon, France
| | - Mathilde Bas
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Francis Canon
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Jean-Marie Heydel
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Fabrice Neiers
- Laboratory: Flavour Perception: Molecular Mechanims (Flavours), INRAE, CNRS, Institut Agro, Université de Bourgogne Franche-Comté, 21000 Dijon, France
- Correspondence:
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11
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Yoon S, Shin M, Shim J. Inter-organ regulation by the brain in Drosophila development and physiology. J Neurogenet 2022:1-13. [DOI: 10.1080/01677063.2022.2137162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Sunggyu Yoon
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
| | - Mingyu Shin
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
| | - Jiwon Shim
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
- Research Institute for Natural Science, Hanyang University, Seoul, Republic of Korea
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, Republic of Korea
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12
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Mendez P, Walsh B, Hallem EA. Using newly optimized genetic tools to probe Strongyloides sensory behaviors. Mol Biochem Parasitol 2022; 250:111491. [PMID: 35697205 PMCID: PMC9339661 DOI: 10.1016/j.molbiopara.2022.111491] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/25/2022] [Accepted: 06/07/2022] [Indexed: 11/26/2022]
Abstract
The oft-neglected human-parasitic threadworm, Strongyloides stercoralis, infects roughly eight percent of the global population, placing disproportionate medical and economic burden upon marginalized communities. While current chemotherapies treat strongyloidiasis, disease recrudescence and the looming threat of anthelminthic resistance necessitate novel strategies for nematode control. Throughout its life cycle, S. stercoralis relies upon sensory cues to aid in environmental navigation and coordinate developmental progression. Odorants, tastants, gases, and temperature have been shown to shape parasite behaviors that drive host seeking and infectivity; however, many of these sensory behaviors remain poorly understood, and their underlying molecular and neural mechanisms are largely uncharacterized. Disruption of sensory circuits essential to parasitism presents a promising strategy for future interventions. In this review, we describe our current understanding of sensory behaviors - namely olfactory, gustatory, gas sensing, and thermosensory behaviors - in Strongyloides spp. We also highlight the ever-growing cache of genetic tools optimized for use in Strongyloides that have facilitated these findings, including transgenesis, CRISPR/Cas9-mediated mutagenesis, RNAi, chemogenetic neuronal silencing, and the use of fluorescent biosensors to measure neuronal activity. Bolstered by these tools, we are poised to enter an era of rapid discovery in Strongyloides sensory neurobiology, which has the potential to shape pioneering advances in the prevention and treatment of strongyloidiasis.
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Affiliation(s)
- Patricia Mendez
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Interdepartmental PhD Program, University of California Los Angeles, Los Angeles, CA, USA.
| | - Breanna Walsh
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Interdepartmental PhD Program, University of California Los Angeles, Los Angeles, CA, USA; Medical Scientist Training Program, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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13
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Taylor AJ, Beauchamp JD, Briand L, Heer M, Hummel T, Margot C, McGrane S, Pieters S, Pittia P, Spence C. Factors affecting flavor perception in space: Does the spacecraft environment influence food intake by astronauts? Compr Rev Food Sci Food Saf 2020; 19:3439-3475. [PMID: 33337044 DOI: 10.1111/1541-4337.12633] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/11/2022]
Abstract
The intention to send a crewed mission to Mars involves a huge amount of planning to ensure a safe and successful mission. Providing adequate amounts of food for the crew is a major task, but 20 years of feeding astronauts on the International Space Station (ISS) have resulted in a good knowledge base. A crucial observation from the ISS is that astronauts typically consume only 80% of their daily calorie requirements when in space. This is despite daily exercise regimes that keep energy usage at very similar levels to those found on Earth. This calorie deficit seems to have little effect on astronauts who spend up to 12 months on the ISS, but given that a mission to Mars would take 30 to 36 months to complete, there is concern that a calorie deficit over this period may lead to adverse effects in crew members. The key question is why astronauts undereat when they have a supply of food designed to fully deliver their nutritional needs. This review focuses on evidence from astronauts that foods taste different in space, compared to on Earth. The underlying hypothesis is that conditions in space may change the perceived flavor of the food, and this flavor change may, in turn, lead to underconsumption by astronauts. The key areas investigated in this review for their potential impact on food intake are the effects of food shelf life, physiological changes, noise, air and water quality on the perception of food flavor, as well as the link between food flavor and food intake.
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Affiliation(s)
| | - Jonathan D Beauchamp
- Department of Sensory Analytics, Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université de Bourgogne Franche-Comté, Dijon, France
| | - Martina Heer
- International University of Applied Sciences, Bad Honnef, Germany
| | - Thomas Hummel
- Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
| | | | - Scott McGrane
- Waltham Petcare Science Institute, Waltham on the Wolds, UK
| | - Serge Pieters
- Haute Ecole Léonard de Vinci, Institut Paul Lambin, Brussels, Belgium
| | - Paola Pittia
- Faculty of Bioscience and Technology for Food, Agriculture, and Environment, University of Teramo, Teramo, Italy
| | - Charles Spence
- Department of Experimental Psychology, University of Oxford, Oxford, UK
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14
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Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes. Proc Natl Acad Sci U S A 2020; 117:17913-17923. [PMID: 32651273 DOI: 10.1073/pnas.1909710117] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Approximately 800 million people worldwide are infected with one or more species of skin-penetrating nematodes. These parasites persist in the environment as developmentally arrested third-stage infective larvae (iL3s) that navigate toward host-emitted cues, contact host skin, and penetrate the skin. iL3s then reinitiate development inside the host in response to sensory cues, a process called activation. Here, we investigate how chemosensation drives host seeking and activation in skin-penetrating nematodes. We show that the olfactory preferences of iL3s are categorically different from those of free-living adults, which may restrict host seeking to iL3s. The human-parasitic threadworm Strongyloides stercoralis and hookworm Ancylostoma ceylanicum have highly dissimilar olfactory preferences, suggesting that these two species may use distinct strategies to target humans. CRISPR/Cas9-mediated mutagenesis of the S. stercoralis tax-4 gene abolishes iL3 attraction to a host-emitted odorant and prevents activation. Our results suggest an important role for chemosensation in iL3 host seeking and infectivity and provide insight into the molecular mechanisms that underlie these processes.
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15
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Long-term activity drives dendritic branch elaboration of a C. elegans sensory neuron. Dev Biol 2020; 461:66-74. [PMID: 31945343 PMCID: PMC7170766 DOI: 10.1016/j.ydbio.2020.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Neuronal activity often leads to alterations in gene expression and cellular architecture. The nematode Caenorhabditis elegans, owing to its compact translucent nervous system, is a powerful system in which to study conserved aspects of the development and plasticity of neuronal morphology. Here we focus on one pair of sensory neurons, termed URX, which the worm uses to sense and avoid high levels of environmental oxygen. Previous studies have reported that the URX neuron pair has variable branched endings at its dendritic sensory tip. By controlling oxygen levels and analyzing mutants, we found that these microtubule-rich branched endings grow over time as a consequence of neuronal activity in adulthood. We also find that the growth of these branches correlates with an increase in cellular sensitivity to particular ranges of oxygen that is observable in the behavior of older worms. Given the strengths of C. elegans as a model organism, URX may serve as a potent system for uncovering genes and mechanisms involved in activity-dependent morphological changes in neurons and possible adaptive changes in the aging nervous system. The dendritic tip of an oxygen-sensing neuron grows elaborate microtubule-rich processes in adult C. elegans. Dendritic tip elaboration depends on the long-term activity of the neuron and calcium. The elaboration correlates with increased sensitivity of the neuron to certain ranges of oxygen as well as higher avoidance of oxygen during bordering behavior. The dendritic tip changes may reflect adaptive changes in physiology and behavior during adulthood.
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16
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Abstract
Carbon dioxide (CO2) is an important sensory cue for many animals, including both parasitic and free-living nematodes. Many nematodes show context-dependent, experience-dependent and/or life-stage-dependent behavioural responses to CO2, suggesting that CO2 plays crucial roles throughout the nematode life cycle in multiple ethological contexts. Nematodes also show a wide range of physiological responses to CO2. Here, we review the diverse responses of parasitic and free-living nematodes to CO2. We also discuss the molecular, cellular and neural circuit mechanisms that mediate CO2 detection in nematodes, and that drive context-dependent and experience-dependent responses of nematodes to CO2.
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17
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A Pervasive Healthcare System for COPD Patients. Diagnostics (Basel) 2019; 9:diagnostics9040135. [PMID: 31581453 PMCID: PMC6963281 DOI: 10.3390/diagnostics9040135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/17/2019] [Accepted: 09/26/2019] [Indexed: 11/21/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is one of the most severe public health problems worldwide. Pervasive computing technology creates a new opportunity to redesign the traditional pattern of medical system. While many pervasive healthcare systems are currently found in the literature, there is little published research on the effectiveness of these paradigms in the medical context. This paper designs and validates a rule-based ontology framework for COPD patients. Unlike conventional systems, this work presents a new vision of telemedicine and remote care solutions that will promote individual self-management and autonomy for COPD patients through an advanced decision-making technique. Rules accuracy estimates were 89% for monitoring vital signs, and environmental factors, and 87% for nutrition facts, and physical activities.
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18
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Koide T, Yabuki Y, Yoshihara Y. Terminal Nerve GnRH3 Neurons Mediate Slow Avoidance of Carbon Dioxide in Larval Zebrafish. Cell Rep 2019; 22:1115-1123. [PMID: 29386100 DOI: 10.1016/j.celrep.2018.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 12/01/2017] [Accepted: 01/05/2018] [Indexed: 12/13/2022] Open
Abstract
Escape responses to threatening stimuli are vital for survival in all animal species. Larval zebrafish display fast escape responses when exposed to tactile, acoustic, and visual stimuli. However, their behavioral responses to chemosensory stimuli remain unknown. In this study, we found that carbon dioxide (CO2) induced a slow avoidance response, which was distinct from the touch-evoked fast escape response. We identified the gonadotropin-releasing hormone 3-expressing terminal nerve as the CO2 sensor in the nose. Wide-field calcium imaging revealed downstream CO2-activated ensembles of neurons along three distinct neural pathways, olfactory, trigeminal, and habenulo-interpeduncular, further reaching the reticulospinal neurons in the hindbrain. Ablation of the nose, terminal nerve, or trigeminal ganglion resulted in a dramatic decrease in CO2-evoked avoidance responses. These findings demonstrate that the terminal nerve-trigeminal system plays a pivotal role in triggering a slow chemosensory avoidance behavior in the larval zebrafish.
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Affiliation(s)
- Tetsuya Koide
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan.
| | - Yoichi Yabuki
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan
| | - Yoshihiro Yoshihara
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Saitama 351-0198, Japan; RIKEN BSI-KAO Collaboration Center, RIKEN Brain Science Institute, Saitama 351-0198, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan.
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19
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Abstract
Female Aedes aegypti mosquitoes bite human hosts to obtain a blood meal and, in the process, act as vectors for many disease-causing viruses, including the dengue, chikungunya, yellow fever, and Zika viruses. After a complete meal, the female mosquitoes lose attraction to their hosts for several days. New research shows that pharmacological activation of neuropeptide Y-like receptor (NPYLR) signaling elicits host aversion in female mosquitoes. This behavior of mosquitoes shows remarkable similarities to a bacterial-aversion behavior of the nematode Caenorhabditis elegans Feeding on pathogenic bacteria causes bloating of the gut in C. elegans that leads to activation of NPYLR signaling and bacterial aversion. Several studies suggest that this newly discovered mechanism underlying foraging may be conserved across a large number of species. A better understanding of the regulation of NPYLR signaling pathways could provide molecular targets for the control of eating behaviors in different animals, including human-disease vectors.
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Affiliation(s)
- Jogender Singh
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA
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20
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Bryant AS, Hallem EA. Terror in the dirt: Sensory determinants of host seeking in soil-transmitted mammalian-parasitic nematodes. Int J Parasitol Drugs Drug Resist 2018; 8:496-510. [PMID: 30396862 PMCID: PMC6287541 DOI: 10.1016/j.ijpddr.2018.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 12/12/2022]
Abstract
Infection with gastrointestinal parasitic nematodes is a major cause of chronic morbidity and economic burden around the world, particularly in low-resource settings. Some parasitic nematode species, including the human-parasitic threadworm Strongyloides stercoralis and human-parasitic hookworms in the genera Ancylostoma and Necator, feature a soil-dwelling infective larval stage that seeks out hosts for infection using a variety of host-emitted sensory cues. Here, we review our current understanding of the behavioral responses of soil-dwelling infective larvae to host-emitted sensory cues, and the molecular and cellular mechanisms that mediate these responses. We also discuss the development of methods for transgenesis and CRISPR/Cas9-mediated targeted mutagenesis in Strongyloides stercoralis and the closely related rat parasite Strongyloides ratti. These methods have established S. stercoralis and S. ratti as genetic model systems for gastrointestinal parasitic nematodes and are enabling more detailed investigations into the neural mechanisms that underlie the sensory-driven behaviors of this medically and economically important class of parasites.
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Affiliation(s)
- Astra S Bryant
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA.
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21
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Cho B, Spratford CM, Yoon S, Cha N, Banerjee U, Shim J. Systemic control of immune cell development by integrated carbon dioxide and hypoxia chemosensation in Drosophila. Nat Commun 2018; 9:2679. [PMID: 29992947 PMCID: PMC6041325 DOI: 10.1038/s41467-018-04990-3] [Citation(s) in RCA: 23] [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: 03/26/2018] [Accepted: 06/08/2018] [Indexed: 02/04/2023] Open
Abstract
Drosophila hemocytes are akin to mammalian myeloid blood cells that function in stress and innate immune-related responses. A multi-potent progenitor population responds to local signals and to systemic stress by expanding the number of functional blood cells. Here we show mechanisms that demonstrate an integration of environmental carbon dioxide (CO2) and oxygen (O2) inputs that initiate a cascade of signaling events, involving multiple organs, as a stress response when the levels of these two important respiratory gases fall below a threshold. The CO2 and hypoxia-sensing neurons interact at the synaptic level in the brain sending a systemic signal via the fat body to modulate differentiation of a specific class of immune cells. Our findings establish a link between environmental gas sensation and myeloid cell development in Drosophila. A similar relationship exists in humans, but the underlying mechanisms remain to be established.
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Affiliation(s)
- Bumsik Cho
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Carrie M Spratford
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Sunggyu Yoon
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Nuri Cha
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea
| | - Utpal Banerjee
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Jiwon Shim
- Department of Life Science, College of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea.
- Research Institute for Natural Science, Hanyang University, Seoul, 04763, Republic of Korea.
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
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22
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Kandasamy M, Aigner L. Reactive Neuroblastosis in Huntington's Disease: A Putative Therapeutic Target for Striatal Regeneration in the Adult Brain. Front Cell Neurosci 2018; 12:37. [PMID: 29593498 PMCID: PMC5854998 DOI: 10.3389/fncel.2018.00037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/31/2018] [Indexed: 01/19/2023] Open
Abstract
The cellular and molecular mechanisms underlying the reciprocal relationship between adult neurogenesis, cognitive and motor functions have been an important focus of investigation in the establishment of effective neural replacement therapies for neurodegenerative disorders. While neuronal loss, reactive gliosis and defects in the self-repair capacity have extensively been characterized in neurodegenerative disorders, the transient excess production of neuroblasts detected in the adult striatum of animal models of Huntington's disease (HD) and in post-mortem brain of HD patients, has only marginally been addressed. This abnormal cellular response in the striatum appears to originate from the selective proliferation and ectopic migration of neuroblasts derived from the subventricular zone (SVZ). Based on and in line with the term "reactive astrogliosis", we propose to name the observed cellular event "reactive neuroblastosis". Although, the functional relevance of reactive neuroblastosis is unknown, we speculate that this process may provide support for the tissue regeneration in compensating the structural and physiological functions of the striatum in lieu of aging or of the neurodegenerative process. Thus, in this review article, we comprehend different possibilities for the regulation of striatal neurogenesis, neuroblastosis and their functional relevance in the context of HD.
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Affiliation(s)
- Mahesh Kandasamy
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
- Faculty Recharge Programme, University Grants Commission (UGC-FRP), New Delhi, India
| | - Ludwig Aigner
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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23
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Guillermin ML, Carrillo MA, Hallem EA. A Single Set of Interneurons Drives Opposite Behaviors in C. elegans. Curr Biol 2017; 27:2630-2639.e6. [PMID: 28823678 PMCID: PMC6193758 DOI: 10.1016/j.cub.2017.07.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/06/2017] [Accepted: 07/10/2017] [Indexed: 12/21/2022]
Abstract
Many chemosensory stimuli evoke innate behavioral responses that can be either appetitive or aversive, depending on an animal's age, prior experience, nutritional status, and environment [1-9]. However, the circuit mechanisms that enable these valence changes are poorly understood. Here, we show that Caenorhabditis elegans can alternate between attractive or aversive responses to carbon dioxide (CO2), depending on its recently experienced CO2 environment. Both responses are mediated by a single pathway of interneurons. The CO2-evoked activity of these interneurons is subject to extreme experience-dependent modulation, enabling them to drive opposite behavioral responses to CO2. Other interneurons in the circuit regulate behavioral sensitivity to CO2 independent of valence. A combinatorial code of neuropeptides acts on the circuit to regulate both valence and sensitivity. Chemosensory valence-encoding interneurons exist across phyla, and valence is typically determined by whether appetitive or aversive interneuron populations are activated. Our results reveal an alternative mechanism of valence determination in which the same interneurons contribute to both attractive and aversive responses through modulation of sensory neuron to interneuron synapses. This circuit design represents a previously unrecognized mechanism for generating rapid changes in innate chemosensory valence.
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Affiliation(s)
- Manon L Guillermin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mayra A Carrillo
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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24
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Bleymehl K, Pérez-Gómez A, Omura M, Moreno-Pérez A, Macías D, Bai Z, Johnson RS, Leinders-Zufall T, Zufall F, Mombaerts P. A Sensor for Low Environmental Oxygen in the Mouse Main Olfactory Epithelium. Neuron 2016; 92:1196-1203. [PMID: 27916458 PMCID: PMC5196021 DOI: 10.1016/j.neuron.2016.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/21/2016] [Accepted: 10/20/2016] [Indexed: 11/24/2022]
Abstract
Sensing the level of oxygen in the external and internal environments is essential for survival. Organisms have evolved multiple mechanisms to sense oxygen. No function in oxygen sensing has been attributed to any mammalian olfactory system. Here, we demonstrate that low environmental oxygen directly activates a subpopulation of sensory neurons in the mouse main olfactory epithelium. These neurons express the soluble guanylate cyclase Gucy1b2 and the cation channel Trpc2. Low oxygen induces calcium influx in these neurons, and Gucy1b2 and Trpc2 are required for these responses. In vivo exposure of a mouse to low environmental oxygen causes Gucy1b2-dependent activation of olfactory bulb neurons in the vicinity of the glomeruli formed by axons of Gucy1b2+ sensory neurons. Low environmental oxygen also induces conditioned place aversion, for which Gucy1b2 and Trpc2 are required. We propose that this chemosensory function enables a mouse to rapidly assess the oxygen level in the external environment.
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Affiliation(s)
- Katherin Bleymehl
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Anabel Pérez-Gómez
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Masayo Omura
- Max Planck Research Unit for Neurogenetics, 60438 Frankfurt, Germany
| | - Ana Moreno-Pérez
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - David Macías
- Department of Physiology, Development & Neuroscience, University of Cambridge, Physiological Laboratory, Cambridge CB2 3EG, UK
| | - Zhaodai Bai
- Max Planck Research Unit for Neurogenetics, 60438 Frankfurt, Germany
| | - Randall S Johnson
- Department of Physiology, Development & Neuroscience, University of Cambridge, Physiological Laboratory, Cambridge CB2 3EG, UK; Department of Cell and Molecular Biology, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Trese Leinders-Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Frank Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany.
| | - Peter Mombaerts
- Max Planck Research Unit for Neurogenetics, 60438 Frankfurt, Germany.
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25
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Witham E, Comunian C, Ratanpal H, Skora S, Zimmer M, Srinivasan S. C. elegans Body Cavity Neurons Are Homeostatic Sensors that Integrate Fluctuations in Oxygen Availability and Internal Nutrient Reserves. Cell Rep 2016; 14:1641-1654. [PMID: 26876168 DOI: 10.1016/j.celrep.2016.01.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/16/2015] [Accepted: 01/14/2016] [Indexed: 12/28/2022] Open
Abstract
It is known that internal physiological state, or interoception, influences CNS function and behavior. However, the neurons and mechanisms that integrate sensory information with internal physiological state remain largely unknown. Here, we identify C. elegans body cavity neurons called URX(L/R) as central homeostatic sensors that integrate fluctuations in oxygen availability with internal metabolic state. We show that depletion of internal body fat reserves increases the tonic activity of URX neurons, which influences the magnitude of the evoked sensory response to oxygen. These responses are integrated via intracellular cGMP and Ca(2+). The extent of neuronal activity thus reflects the balance between the perception of oxygen and available fat reserves. The URX homeostatic sensor ensures that neural signals that stimulate fat loss are only deployed when there are sufficient fat reserves to do so. Our results uncover an interoceptive neuroendocrine axis that relays internal state information to the nervous system.
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Affiliation(s)
- Emily Witham
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Dorris Neuroscience Center, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Claudio Comunian
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Harkaranveer Ratanpal
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Dorris Neuroscience Center, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Susanne Skora
- Research Institute of Molecular Pathology IMP, Vienna Biocenter VBC, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Manuel Zimmer
- Research Institute of Molecular Pathology IMP, Vienna Biocenter VBC, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Supriya Srinivasan
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Dorris Neuroscience Center, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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26
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Piersanti S, Frati F, Rebora M, Salerno G. Carbon dioxide detection in adult Odonata. ZOOLOGY 2016; 119:137-142. [PMID: 26831359 DOI: 10.1016/j.zool.2016.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/26/2015] [Accepted: 01/10/2016] [Indexed: 12/27/2022]
Abstract
The present paper shows, by means of single-cell recordings, responses of antennal sensory neurons of the damselfly Ischnura elegans when stimulated by air streams at different CO2 concentrations. Unlike most insects, but similarly to termites, centipedes and ticks, Odonata possess sensory neurons strongly inhibited by CO2, with the magnitude of the off-response depending upon the CO2 concentration. The Odonata antennal sensory neurons responding to CO2 are also sensitive to airborne odors; in particular, the impulse frequency is increased by isoamylamine and decreased by heptanoic and pentanoic acid. Further behavioral investigations are necessary to assign a biological role to carbon dioxide detection in Odonata.
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Affiliation(s)
- Silvana Piersanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto, 06123 Perugia, Italy.
| | - Francesca Frati
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - Manuela Rebora
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto, 06123 Perugia, Italy
| | - Gianandrea Salerno
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
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27
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Maruyama IN. Receptor Guanylyl Cyclases in Sensory Processing. Front Endocrinol (Lausanne) 2016; 7:173. [PMID: 28123378 PMCID: PMC5225109 DOI: 10.3389/fendo.2016.00173] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 12/28/2016] [Indexed: 11/18/2022] Open
Abstract
Invertebrate models have generated many new insights into transmembrane signaling by cell-surface receptors. This review focuses on receptor guanylyl cyclases (rGCs) and describes recent advances in understanding their roles in sensory processing in the nematode, Caenorhabditis elegans. A complete analysis of the C. elegans genome elucidated 27 rGCs, an unusually large number compared with mammalian genomes, which encode 7 rGCs. Most C. elegans rGCs are expressed in sensory neurons and play roles in sensory processing, including gustation, thermosensation, olfaction, and phototransduction, among others. Recent studies have found that by producing a second messenger, guanosine 3',5'-cyclic monophosphate, some rGCs act as direct sensor molecules for ions and temperatures, while others relay signals from G protein-coupled receptors. Interestingly, genetic and biochemical analyses of rGCs provide the first example of an obligate heterodimeric rGC. Based on recent structural studies of rGCs in mammals and other organisms, molecular mechanisms underlying activation of rGCs are also discussed in this review.
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Affiliation(s)
- Ichiro N. Maruyama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- *Correspondence: Ichiro N. Maruyama,
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Environmental CO2 inhibits Caenorhabditis elegans egg-laying by modulating olfactory neurons and evokes widespread changes in neural activity. Proc Natl Acad Sci U S A 2015; 112:E3525-34. [PMID: 26100886 DOI: 10.1073/pnas.1423808112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Carbon dioxide (CO2) gradients are ubiquitous and provide animals with information about their environment, such as the potential presence of prey or predators. The nematode Caenorhabditis elegans avoids elevated CO2, and previous work identified three neuron pairs called "BAG," "AFD," and "ASE" that respond to CO2 stimuli. Using in vivo Ca(2+) imaging and behavioral analysis, we show that C. elegans can detect CO2 independently of these sensory pathways. Many of the C. elegans sensory neurons we examined, including the AWC olfactory neurons, the ASJ and ASK gustatory neurons, and the ASH and ADL nociceptors, respond to a rise in CO2 with a rise in Ca(2+). In contrast, glial sheath cells harboring the sensory endings of C. elegans' major chemosensory neurons exhibit strong and sustained decreases in Ca(2+) in response to high CO2. Some of these CO2 responses appear to be cell intrinsic. Worms therefore may couple detection of CO2 to that of other cues at the earliest stages of sensory processing. We show that C. elegans persistently suppresses oviposition at high CO2. Hermaphrodite-specific neurons (HSNs), the executive neurons driving egg-laying, are tonically inhibited when CO2 is elevated. CO2 modulates the egg-laying system partly through the AWC olfactory neurons: High CO2 tonically activates AWC by a cGMP-dependent mechanism, and AWC output inhibits the HSNs. Our work shows that CO2 is a more complex sensory cue for C. elegans than previously thought, both in terms of behavior and neural circuitry.
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Sleep- and wake-dependent changes in neuronal activity and reactivity demonstrated in fly neurons using in vivo calcium imaging. Proc Natl Acad Sci U S A 2015; 112:4785-90. [PMID: 25825756 DOI: 10.1073/pnas.1419603112] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sleep in Drosophila shares many features with mammalian sleep, but it remains unknown whether spontaneous and evoked activity of individual neurons change with the sleep/wake cycle in flies as they do in mammals. Here we used calcium imaging to assess how the Kenyon cells in the fly mushroom bodies change their activity and reactivity to stimuli during sleep, wake, and after short or long sleep deprivation. As before, sleep was defined as a period of immobility of >5 min associated with a reduced behavioral response to a stimulus. We found that calcium levels in Kenyon cells decline when flies fall asleep and increase when they wake up. Moreover, calcium transients in response to two different stimuli are larger in awake flies than in sleeping flies. The activity of Kenyon cells is also affected by sleep/wake history: in awake flies, more cells are spontaneously active and responding to stimuli if the last several hours (5-8 h) before imaging were spent awake rather than asleep. By contrast, long wake (≥29 h) reduces both baseline and evoked neural activity and decreases the ability of neurons to respond consistently to the same repeated stimulus. The latter finding may underlie some of the negative effects of sleep deprivation on cognitive performance and is consistent with the occurrence of local sleep during wake as described in behaving rats. Thus, calcium imaging uncovers new similarities between fly and mammalian sleep: fly neurons are more active and reactive in wake than in sleep, and their activity tracks sleep/wake history.
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Omura M, Mombaerts P. Trpc2-expressing sensory neurons in the mouse main olfactory epithelium of type B express the soluble guanylate cyclase Gucy1b2. Mol Cell Neurosci 2015; 65:114-24. [PMID: 25701815 PMCID: PMC4396857 DOI: 10.1016/j.mcn.2015.02.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/06/2015] [Accepted: 02/17/2015] [Indexed: 01/20/2023] Open
Abstract
Chemoreception in the mouse olfactory system occurs primarily at two chemosensory epithelia in the nasal cavity: the main olfactory epithelium (MOE) and the vomeronasal epithelium. The canonical chemosensory neurons in the MOE, the olfactory sensory neurons (OSNs), express the odorant receptor (OR) gene repertoire, and depend on Adcy3 and Cnga2 for chemosensory signal transduction. The canonical chemosensory neurons in the vomeronasal epithelium, the vomeronasal sensory neurons (VSNs), express two unrelated vomeronasal receptor (VR) gene repertoires, and involve Trpc2 for chemosensory signal transduction. Recently we reported the discovery of two types of neurons in the mouse MOE that express Trcp2 in addition to Cnga2. These cell types can be distinguished at the single-cell level by expression of Adcy3: positive, type A and negative, type B. Some type A cells express OR genes. Thus far there is no specific gene or marker for type B cells, hampering further analyses such as physiological recordings. Here, we show that among MOE cells, type B cells are unique in their expression of the soluble guanylate cyclase Gucy1b2. We came across Gucy1b2 in an explorative approach based on Long Serial Analysis of Gene Expression (LongSAGE) that we applied to single red-fluorescent cells isolated from whole olfactory mucosa and vomeronasal organ of mice of a novel Trcp2-IRES-taumCherry gene-targeted strain. The generation of a novel Gucy1b2-IRES-tauGFP gene-targeted strain enabled us to visualize coalescence of axons of type B cells into glomeruli in the main olfactory bulb. Our molecular and anatomical analyses define Gucy1b2 as a marker for type B cells within the MOE. The Gucy1b2-IRES-tauGFP strain will be useful for physiological, molecular, cellular, and anatomical studies of this newly described chemosensory subsystem. Trpc2 + cells exist as type A and type B in the mouse main olfactory epithelium. We find no evidence for expression of chemosensory GPCR genes in type B cells. We identify the soluble guanylate cyclase Gucy1b2 as a marker for type B cells. Gucy1b2-IRES-tauGFP knockin mice will be useful for physiological studies.
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Affiliation(s)
- Masayo Omura
- Max Planck Research Unit for Neurogenetics, Frankfurt, Germany
| | - Peter Mombaerts
- Max Planck Research Unit for Neurogenetics, Frankfurt, Germany.
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Intracellular bicarbonate regulates action potential generation via KCNQ channel modulation. J Neurosci 2014; 34:4409-17. [PMID: 24647960 DOI: 10.1523/jneurosci.3836-13.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Bicarbonate (HCO3(-)) is an abundant anion that regulates extracellular and intracellular pH. Here, we use patch-clamp techniques to assess regulation of hippocampal CA3 pyramidal cell excitability by HCO3(-) in acute brain slices from C57BL/6 mice. We found that increasing HCO3(-) levels enhances action potential (AP) generation in both the soma and axon initial segment (AIS) by reducing Kv7/KCNQ channel activity, independent of pH (i.e., at a constant pH of 7.3). Conversely, decreasing intracellular HCO3(-) leads to attenuation of AP firing. We show that HCO3(-) interferes with Kv7/KCNQ channel activation by phosphatidylinositol-4,5-biphosphate. Consequently, we propose that, even in the presence of a local depolarizing Cl(-) gradient, HCO3(-) efflux through GABAA receptors may ensure the inhibitory effect of axoaxonic cells at the AIS due to activation of Kv7/KCNQ channels.
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Smith ESJ, Martinez-Velazquez L, Ringstad N. A chemoreceptor that detects molecular carbon dioxide. J Biol Chem 2013; 288:37071-81. [PMID: 24240097 DOI: 10.1074/jbc.m113.517367] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Animals from diverse phyla possess neurons that are activated by the product of aerobic respiration, CO2. It has long been thought that such neurons primarily detect the CO2 metabolites protons and bicarbonate. We have determined the chemical tuning of isolated CO2 chemosensory BAG neurons of the nematode Caenorhabditis elegans. We show that BAG neurons are principally tuned to detect molecular CO2, although they can be activated by acid stimuli. One component of the BAG transduction pathway, the receptor-type guanylate cyclase GCY-9, suffices to confer cellular sensitivity to both molecular CO2 and acid, indicating that it is a bifunctional chemoreceptor. We speculate that in other animals, receptors similarly capable of detecting molecular CO2 might mediate effects of CO2 on neural circuits and behavior.
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Affiliation(s)
- Ewan St John Smith
- From the Skirball Institute of Biomolecular Medicine, Molecular Neurobiology Program and Department of Cell Biology, New York University Medical Center, New York, New York 10016 and
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Carrillo MA, Guillermin ML, Rengarajan S, Okubo RP, Hallem EA. O2-sensing neurons control CO2 response in C. elegans. J Neurosci 2013; 33:9675-83. [PMID: 23739964 PMCID: PMC3721734 DOI: 10.1523/jneurosci.4541-12.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 04/21/2013] [Accepted: 04/27/2013] [Indexed: 11/21/2022] Open
Abstract
Sensory behaviors are often flexible, allowing animals to generate context-appropriate responses to changing environmental conditions. To investigate the neural basis of behavioral flexibility, we examined the regulation of carbon dioxide (CO2) response in the nematode Caenorhabditis elegans. CO2 is a critical sensory cue for many animals, mediating responses to food, conspecifics, predators, and hosts (Scott, 2011; Buehlmann et al., 2012; Chaisson and Hallem, 2012). In C. elegans, CO2 response is regulated by the polymorphic neuropeptide receptor NPR-1: animals with the N2 allele of npr-1 avoid CO2, whereas animals with the Hawaiian (HW) allele or an npr-1 loss-of-function (lf) mutation appear virtually insensitive to CO2 (Hallem and Sternberg, 2008; McGrath et al., 2009). Here we show that ablating the oxygen (O2)-sensing URX neurons in npr-1(lf) mutants restores CO2 avoidance, suggesting that NPR-1 enables CO2 avoidance by inhibiting URX neurons. URX was previously shown to be activated by increases in ambient O2 (Persson et al., 2009; Zimmer et al., 2009; Busch et al., 2012). We find that, in npr-1(lf) mutants, O2-induced activation of URX inhibits CO2 avoidance. Moreover, both HW and npr-1(lf) animals avoid CO2 under low O2 conditions, when URX is inactive. Our results demonstrate that CO2 response is determined by the activity of O2-sensing neurons and suggest that O2-dependent regulation of CO2 avoidance is likely to be an ecologically relevant mechanism by which nematodes navigate gas gradients.
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Affiliation(s)
- Mayra A. Carrillo
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095
| | - Manon L. Guillermin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095
| | - Sophie Rengarajan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095
| | - Ryo P. Okubo
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095
| | - Elissa A. Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095
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Keil TA. Sensory cilia in arthropods. ARTHROPOD STRUCTURE & DEVELOPMENT 2012; 41:515-34. [PMID: 22814269 DOI: 10.1016/j.asd.2012.07.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 05/11/2023]
Abstract
In arthropods, the modified primary cilium is a structure common to all peripheral sensory neurons other than photoreceptors. Since its first description in 1958, it has been investigated in great detail in numerous sense organs (sensilla) of many insect species by means of electron microscopy and electrophysiology. The perfection of molecular biological methods has led to an enormous advance in our knowledge about development and function of sensory cilia in the fruitfly since the end of the last century. The cilia show a wealth of adaptations according to their different physiological roles: chemoreception, mechanoreception, hygroreception, and thermoreception. Divergent types of receptors and channels have evolved fulfilling these tasks. The number of olfactory receptor genes can be close to 300 in ants, whereas in crickets slightest mechanical stimuli are detected by the interaction of extremely sophisticated biomechanical devices with mechanosensory cilia. Despite their enormous morphological and physiological divergence, sensilla and sensory cilia develop according to a stereotyped pattern. Intraflagellar transport genes have been found to be decisive for proper development and function.
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Affiliation(s)
- Thomas A Keil
- Max-Planck-Institute of Biochemistry, Department of Molecular Structural Biology, Martinsried, Germany.
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Buck J, Levin LR. Physiological sensing of carbon dioxide/bicarbonate/pH via cyclic nucleotide signaling. SENSORS 2012; 11:2112-28. [PMID: 21544217 PMCID: PMC3085406 DOI: 10.3390/s110202112] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Carbon dioxide (CO2) is produced by living organisms as a byproduct of metabolism. In physiological systems, CO2 is unequivocally linked with bicarbonate (HCO3−) and pH via a ubiquitous family of carbonic anhydrases, and numerous biological processes are dependent upon a mechanism for sensing the level of CO2, HCO3, and/or pH. The discovery that soluble adenylyl cyclase (sAC) is directly regulated by bicarbonate provided a link between CO2/HCO3/pH chemosensing and signaling via the widely used second messenger cyclic AMP. This review summarizes the evidence that bicarbonate-regulated sAC, and additional, subsequently identified bicarbonate-regulate nucleotidyl cyclases, function as evolutionarily conserved CO2/HCO3/pH chemosensors in a wide variety of physiological systems.
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Affiliation(s)
- Jochen Buck
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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Ma DK, Ringstad N. The neurobiology of sensing respiratory gases for the control of animal behavior. ACTA ACUST UNITED AC 2012; 7:246-253. [PMID: 22876258 DOI: 10.1007/s11515-012-1219-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Aerobic metabolism is fundamental for almost all animal life. Cellular consumption of oxygen (O(2)) and production of carbon dioxide (CO(2)) signal metabolic states and physiological stresses. These respiratory gases are also detected as environmental cues that can signal external food quality and the presence of prey, predators and mates. In both contexts, animal nervous systems are endowed with mechanisms for sensing O(2)/CO(2) to trigger appropriate behaviors and maintain homeostasis of internal O(2)/CO(2). Although different animal species show different behavioral responses to O(2)/CO(2), some underlying molecular mechanisms and pathways that function in the detection of respiratory gases are fundamentally similar and evolutionarily conserved. Studies of Caenorhabditis elegans and Drosophila melanogaster have identified roles for cyclic nucleotide signaling and the hypoxia inducible factor (HIF) transcriptional pathway in mediating behavioral responses to respiratory gases. Understanding how simple invertebrate nervous systems detect respiratory gases to control behavior might reveal general principles common to nematodes, insects and vertebrates that function in the molecular sensing of respiratory gases and the neural control of animal behaviors.
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Affiliation(s)
- Dengke K Ma
- Department of Biology, and McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA
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Abstract
When animals move, respiration increases to adapt for increased energy demands; the underlying mechanisms are still not understood. We investigated the neural substrates underlying the respiratory changes in relation to movement in lampreys. We showed that respiration increases following stimulation of the mesencephalic locomotor region (MLR) in an in vitro isolated preparation, an effect that persists in the absence of the spinal cord and caudal brainstem. By using electrophysiological and anatomical techniques, including whole-cell patch recordings, we identified a subset of neurons located in the dorsal MLR that send direct inputs to neurons in the respiratory generator. In semi-intact preparations, blockade of this region with 6-cyano-7-nitroquinoxaline-2,3-dione and (2R)-amino-5-phosphonovaleric acid greatly reduced the respiratory increases without affecting the locomotor movements. These results show that neurons in the respiratory generator receive direct glutamatergic connections from the MLR and that a subpopulation of MLR neurons plays a key role in the respiratory changes linked to movement.
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