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Ripoll-Sánchez L, Watteyne J, Sun H, Fernandez R, Taylor SR, Weinreb A, Bentley BL, Hammarlund M, Miller DM, Hobert O, Beets I, Vértes PE, Schafer WR. The neuropeptidergic connectome of C. elegans. Neuron 2023; 111:3570-3589.e5. [PMID: 37935195 PMCID: PMC7615469 DOI: 10.1016/j.neuron.2023.09.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 08/02/2023] [Accepted: 09/29/2023] [Indexed: 11/09/2023]
Abstract
Efforts are ongoing to map synaptic wiring diagrams, or connectomes, to understand the neural basis of brain function. However, chemical synapses represent only one type of functionally important neuronal connection; in particular, extrasynaptic, "wireless" signaling by neuropeptides is widespread and plays essential roles in all nervous systems. By integrating single-cell anatomical and gene-expression datasets with biochemical analysis of receptor-ligand interactions, we have generated a draft connectome of neuropeptide signaling in the C. elegans nervous system. This network is characterized by high connection density, extended signaling cascades, autocrine foci, and a decentralized topology, with a large, highly interconnected core containing three constituent communities sharing similar patterns of input connectivity. Intriguingly, several key network hubs are little-studied neurons that appear specialized for peptidergic neuromodulation. We anticipate that the C. elegans neuropeptidergic connectome will serve as a prototype to understand how networks of neuromodulatory signaling are organized.
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Affiliation(s)
- Lidia Ripoll-Sánchez
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Psychiatry, Cambridge University, Cambridge, UK
| | - Jan Watteyne
- Department of Biology, KU Leuven, Leuven, Belgium
| | - HaoSheng Sun
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert Fernandez
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA
| | - Seth R Taylor
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Alexis Weinreb
- Departments of Genetics and Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Barry L Bentley
- Cardiff School of Technologies, Cardiff Metropolitan University, Cardiff, UK
| | - Marc Hammarlund
- Departments of Genetics and Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Oliver Hobert
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA
| | - Isabel Beets
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Petra E Vértes
- Department of Psychiatry, Cambridge University, Cambridge, UK
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Biology, KU Leuven, Leuven, Belgium.
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2
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Wu T, Ge M, Wu M, Duan F, Liang J, Chen M, Gracida X, Liu H, Yang W, Dar AR, Li C, Butcher RA, Saltzman AL, Zhang Y. Pathogenic bacteria modulate pheromone response to promote mating. Nature 2023; 613:324-331. [PMID: 36599989 PMCID: PMC10732163 DOI: 10.1038/s41586-022-05561-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 11/11/2022] [Indexed: 01/05/2023]
Abstract
Pathogens generate ubiquitous selective pressures and host-pathogen interactions alter social behaviours in many animals1-4. However, very little is known about the neuronal mechanisms underlying pathogen-induced changes in social behaviour. Here we show that in adult Caenorhabditis elegans hermaphrodites, exposure to a bacterial pathogen (Pseudomonas aeruginosa) modulates sensory responses to pheromones by inducing the expression of the chemoreceptor STR-44 to promote mating. Under standard conditions, C. elegans hermaphrodites avoid a mixture of ascaroside pheromones to facilitate dispersal5-13. We find that exposure to the pathogenic Pseudomonas bacteria enables pheromone responses in AWA sensory neurons, which mediate attractive chemotaxis, to suppress the avoidance. Pathogen exposure induces str-44 expression in AWA neurons, a process regulated by a transcription factor zip-5 that also displays a pathogen-induced increase in expression in AWA. STR-44 acts as a pheromone receptor and its function in AWA neurons is required for pathogen-induced AWA pheromone response and suppression of pheromone avoidance. Furthermore, we show that C. elegans hermaphrodites, which reproduce mainly through self-fertilization, increase the rate of mating with males after pathogen exposure and that this increase requires str-44 in AWA neurons. Thus, our results uncover a causal mechanism for pathogen-induced social behaviour plasticity, which can promote genetic diversity and facilitate adaptation of the host animals.
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Affiliation(s)
- Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Minghai Ge
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Min Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Jingting Liang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Maoting Chen
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Xicotencatl Gracida
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Chengyin Li
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Arneet L Saltzman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
- Center for Brain Science, Harvard University, Cambridge, MA, USA.
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3
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Pandey P, Kaur G, Babu K. Crosstalk between neurons and glia through G-protein coupled receptors: Insights from Caenorhabditis elegans. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 193:119-144. [PMID: 36357074 DOI: 10.1016/bs.pmbts.2022.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The past decades have witnessed a dogmatic shift from glia as supporting cells in the nervous system to their active roles in neurocentric functions. Neurons and glia communicate and show bidirectional responses through tripartite synapses. Studies across species indicate that neurotransmitters released by neurons are perceived by glial receptors, which allow for gliotransmitter release. These gliotransmitters can result in activation of neurons via neuronal GPCR receptors. However, studies of these molecular interactions are in their infancy. Caenorhabditis elegans has a conserved neuron-glia architectural repertoire with molecular and functional resemblance to mammals. Further, glia in C. elegans can be manipulated through ablation and mutations allowing for deciphering of glial dependent processes in vivo at single glial resolutions. Here, we will review recent findings from vertebrate and invertebrate organisms with a focus on how C. elegans can be used to advance our understanding of neuron-glia interactions through GPCRs.
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Affiliation(s)
- Pratima Pandey
- Indian Institute of Science Education and Research, Mohali, Punjab, India.
| | - Gazaldeep Kaur
- National Agri-Food Biotechnology Institute, Mohali, Punjab, India
| | - Kavita Babu
- Indian Institute of Science, Bangalore, Karnataka, India.
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4
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Valperga G, de Bono M. Impairing one sensory modality enhances another by reconfiguring peptidergic signalling in Caenorhabditis elegans. eLife 2022; 11:68040. [PMID: 35201977 PMCID: PMC8871372 DOI: 10.7554/elife.68040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 02/07/2022] [Indexed: 12/05/2022] Open
Abstract
Animals that lose one sensory modality often show augmented responses to other sensory inputs. The mechanisms underpinning this cross-modal plasticity are poorly understood. We probe such mechanisms by performing a forward genetic screen for mutants with enhanced O2 perception in Caenorhabditis elegans. Multiple mutants exhibiting increased O2 responsiveness concomitantly show defects in other sensory responses. One mutant, qui-1, defective in a conserved NACHT/WD40 protein, abolishes pheromone-evoked Ca2+ responses in the ADL pheromone-sensing neurons. At the same time, ADL responsiveness to pre-synaptic input from O2-sensing neurons is heightened in qui-1, and other sensory defective mutants, resulting in enhanced neurosecretion although not increased Ca2+ responses. Expressing qui-1 selectively in ADL rescues both the qui-1 ADL neurosecretory phenotype and enhanced escape from 21% O2. Profiling ADL neurons in qui-1 mutants highlights extensive changes in gene expression, notably of many neuropeptide receptors. We show that elevated ADL expression of the conserved neuropeptide receptor NPR-22 is necessary for enhanced ADL neurosecretion in qui-1 mutants, and is sufficient to confer increased ADL neurosecretion in control animals. Sensory loss can thus confer cross-modal plasticity by changing the peptidergic connectome.
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Affiliation(s)
- Giulio Valperga
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
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5
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OKAHATA M, MOTOMURA H, OHTA A, KUHARA A. Molecular physiology regulating cold tolerance and acclimation of Caenorhabditis elegans. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2022; 98:126-139. [PMID: 35283408 PMCID: PMC8948419 DOI: 10.2183/pjab.98.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
Many organisms can survive and proliferate in changing environmental temperatures. Here, we introduce a molecular physiological mechanism for cold tolerance and acclimation of the nematode Caenorhabditis elegans on the basis of previous reports and a new result. Three types of thermosensory neurons located in the head, ASJ, ASG, and ADL, regulate cold tolerance and acclimation. In ASJ, components of the light-signaling pathway are involved in thermosensation. In ASG, mechanoreceptor DEG-1 acts as thermoreceptor. In ADL, transient receptor potential channels are thermoreceptors; however, the presence of an additional unidentified thermoreceptor is also speculated. ADL thermoresponsivity is modulated by oxygen sensory signaling from URX oxygen sensory neurons via hub interneurons. ASJ releases insulin and steroid hormones that are received by the intestine, which results in lipid composition changing with cold tolerance. Additionally, the intestinal transcriptional alteration affects sperm functions, which in turn affects the thermosensitivity of ASJ; thus, the neuron-intestine-sperm-neuron tissue circuit is essential for cold tolerance.
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Affiliation(s)
- Misaki OKAHATA
- Graduate School of Natural Science, Konan University, Kobe, Hyogo, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, Japan
| | - Haruka MOTOMURA
- Graduate School of Natural Science, Konan University, Kobe, Hyogo, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, Japan
| | - Akane OHTA
- Graduate School of Natural Science, Konan University, Kobe, Hyogo, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, Japan
| | - Atsushi KUHARA
- Graduate School of Natural Science, Konan University, Kobe, Hyogo, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Hyogo, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Hyogo, Japan
- PRIME, AMED, Japan Agency for Medical Research and Development, Tokyo, Japan
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6
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Luo J, Portman DS. Sex-specific, pdfr-1-dependent modulation of pheromone avoidance by food abundance enables flexibility in C. elegans foraging behavior. Curr Biol 2021; 31:4449-4461.e4. [PMID: 34437843 DOI: 10.1016/j.cub.2021.07.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/20/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022]
Abstract
To make adaptive feeding and foraging decisions, animals must integrate diverse sensory streams with multiple dimensions of internal state. In C. elegans, foraging and dispersal behaviors are influenced by food abundance, population density, and biological sex, but the neural and genetic mechanisms that integrate these signals are poorly understood. Here, by systematically varying food abundance, we find that chronic avoidance of the population-density pheromone ascr#3 is modulated by food thickness, such that hermaphrodites avoid ascr#3 only when food is scarce. The integration of food and pheromone signals requires the conserved neuropeptide receptor PDFR-1, as pdfr-1 mutant hermaphrodites display strong ascr#3 avoidance, even when food is abundant. Conversely, increasing PDFR-1 signaling inhibits ascr#3 aversion when food is sparse, indicating that this signal encodes information about food abundance. In both wild-type and pdfr-1 hermaphrodites, chronic ascr#3 avoidance requires the ASI sensory neurons. In contrast, PDFR-1 acts in interneurons, suggesting that it modulates processing of the ascr#3 signal. Although a sex-shared mechanism mediates ascr#3 avoidance, food thickness modulates this behavior only in hermaphrodites, indicating that PDFR-1 signaling has distinct functions in the two sexes. Supporting the idea that this mechanism modulates foraging behavior, ascr#3 promotes ASI-dependent dispersal of hermaphrodites from food, an effect that is markedly enhanced when food is scarce. Together, these findings identify a neurogenetic mechanism that sex-specifically integrates population and food abundance, two important dimensions of environmental quality, to optimize foraging decisions. Further, they suggest that modulation of attention to sensory signals could be an ancient, conserved function of pdfr-1.
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Affiliation(s)
- Jintao Luo
- Department of Biomedical Genetics, Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Douglas S Portman
- Department of Biomedical Genetics, Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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7
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Reilly DK, McGlame EJ, Vandewyer E, Robidoux AN, Muirhead CS, Northcott HT, Joyce W, Alkema MJ, Gegear RJ, Beets I, Srinivasan J. Distinct neuropeptide-receptor modules regulate a sex-specific behavioral response to a pheromone. Commun Biol 2021; 4:1018. [PMID: 34465863 PMCID: PMC8408276 DOI: 10.1038/s42003-021-02547-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 08/09/2021] [Indexed: 02/07/2023] Open
Abstract
Dioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.
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Affiliation(s)
- Douglas K. Reilly
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA ,grid.429997.80000 0004 1936 7531Present Address: Tufts University, Medford, MA USA
| | - Emily J. McGlame
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA ,Present Address: AbbVie Foundational Neuroscience Center, Cambridge, MA USA
| | - Elke Vandewyer
- grid.5596.f0000 0001 0668 7884Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Annalise N. Robidoux
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA
| | - Caroline S. Muirhead
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA
| | - Haylea T. Northcott
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA ,grid.423532.10000 0004 0516 8515Present Address: Optum, Hartford, CT USA
| | - William Joyce
- grid.168645.80000 0001 0742 0364Neurobiology Department, University of Massachusetts Medical School, Worcester, MA USA
| | - Mark J. Alkema
- grid.168645.80000 0001 0742 0364Neurobiology Department, University of Massachusetts Medical School, Worcester, MA USA
| | - Robert J. Gegear
- grid.266686.a0000000102217463Department of Biology, University of Massachusetts Dartmouth, Dartmouth, MA USA
| | - Isabel Beets
- grid.5596.f0000 0001 0668 7884Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Jagan Srinivasan
- grid.268323.e0000 0001 1957 0327Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA USA
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8
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Dal Bello M, Pérez-Escudero A, Schroeder FC, Gore J. Inversion of pheromone preference optimizes foraging in C. elegans. eLife 2021; 10:58144. [PMID: 34227470 PMCID: PMC8260229 DOI: 10.7554/elife.58144] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/09/2021] [Indexed: 12/20/2022] Open
Abstract
Foraging animals have to locate food sources that are usually patchily distributed and subject to competition. Deciding when to leave a food patch is challenging and requires the animal to integrate information about food availability with cues signaling the presence of other individuals (e.g., pheromones). To study how social information transmitted via pheromones can aid foraging decisions, we investigated the behavioral responses of the model animal Caenorhabditis elegans to food depletion and pheromone accumulation in food patches. We experimentally show that animals consuming a food patch leave it at different times and that the leaving time affects the animal preference for its pheromones. In particular, worms leaving early are attracted to their pheromones, while worms leaving later are repelled by them. We further demonstrate that the inversion from attraction to repulsion depends on associative learning and, by implementing a simple model, we highlight that it is an adaptive solution to optimize food intake during foraging.
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Affiliation(s)
- Martina Dal Bello
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Alfonso Pérez-Escudero
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, United States.,Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse; CNRS; UPS, Toulouse, France
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, New York, United States
| | - Jeff Gore
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
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9
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Abergel Z, Shaked M, Shukla V, Wu ZX, Gross E. The phosphatidylinositol transfer protein PITP-1 facilitates fast recovery of eating behavior after hypoxia in the nematode Caenorhabditis elegans. FASEB J 2021; 35:e21202. [PMID: 33368638 PMCID: PMC7839455 DOI: 10.1096/fj.202000704r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 10/21/2020] [Accepted: 11/03/2020] [Indexed: 12/18/2022]
Abstract
Among the fascinating adaptations to limiting oxygen conditions (hypoxia) is the suppression of food intake and weight loss. In humans, this phenomenon is called high-altitude anorexia and is observed in people suffering from acute mountain syndrome. The high-altitude anorexia appears to be conserved in evolution and has been seen in species across the animal kingdom. However, the mechanism underlying the recovery of eating behavior after hypoxia is still not known. Here, we show that the phosphatidylinositol transfer protein PITP-1 is essential for the fast recovery of eating behavior after hypoxia in the nematode Caenorhabditis elegans. Unlike the neuroglobin GLB-5 that accelerates the recovery of eating behavior through its function in the oxygen (O2 )-sensing neurons, PITP-1 appears to act downstream, in neurons that express the mod-1 serotonin receptor. Indeed, pitp-1 mutants display wild-type-like O2 -evoked-calcium responses in the URX O2 -sensing neuron. Intriguingly, loss-of-function of protein kinase C 1 (PKC-1) rescues pitp-1 mutants' recovery after hypoxia. Increased diacylglycerol (DAG), which activates PKC-1, attenuates the recovery of wild-type worms. Together, these data suggest that PITP-1 enables rapid recovery of eating behavior after hypoxia by limiting DAG's availability, thereby limiting PKC activity in mod-1-expressing neurons.
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Affiliation(s)
- Zohar Abergel
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maayan Shaked
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Virendra Shukla
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Zheng-Xing Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Einav Gross
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
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10
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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11
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Tataridas-Pallas N, Thompson MA, Howard A, Brown I, Ezcurra M, Wu Z, Silva IG, Saunter CD, Kuerten T, Weinkove D, Blackwell TK, Tullet JMA. Neuronal SKN-1B modulates nutritional signalling pathways and mitochondrial networks to control satiety. PLoS Genet 2021; 17:e1009358. [PMID: 33661901 PMCID: PMC7932105 DOI: 10.1371/journal.pgen.1009358] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/17/2021] [Indexed: 12/14/2022] Open
Abstract
The feeling of hunger or satiety results from integration of the sensory nervous system with other physiological and metabolic cues. This regulates food intake, maintains homeostasis and prevents disease. In C. elegans, chemosensory neurons sense food and relay information to the rest of the animal via hormones to control food-related behaviour and physiology. Here we identify a new component of this system, SKN-1B which acts as a central food-responsive node, ultimately controlling satiety and metabolic homeostasis. SKN-1B, an ortholog of mammalian NF-E2 related transcription factors (Nrfs), has previously been implicated with metabolism, respiration and the increased lifespan incurred by dietary restriction. Here we show that SKN-1B acts in two hypothalamus-like ASI neurons to sense food, communicate nutritional status to the organism, and control satiety and exploratory behaviours. This is achieved by SKN-1B modulating endocrine signalling pathways (IIS and TGF-β), and by promoting a robust mitochondrial network. Our data suggest a food-sensing and satiety role for mammalian Nrf proteins. Deciding when and how much to eat is important for maintaining health and preventing disease. It requires an intricate molecular level of communication between our nervous, physiological, and metabolic systems. These signals stimulate food intake, and afterwards the feeling of satiety which makes us stop eating. We have studied these phenomena using the simple nematode worm C. elegans which has a fully mapped nervous system and quantifiable food-related behaviours. In C. elegans, chemosensory neurons sense food and communicate this to the rest of the animal via hormones to control food-related behaviour and associated physiological changes. Here we identify a new central node of this system, the C. elegans gene SKN-1B, which acts in two sensory neurons to sense food, communicate food-status to the rest of the worm, and control satiety and exploratory behaviours. It does this by altering hormonal signalling (Insulin and Transforming Growth Factor-β), and by promoting a strong mitochondrial network. The mammalian equivalents of SKN-1B are the NF-E2 related transcription factors (Nrfs), which have previously been implicated with metabolism and respiration. Our data suggest a new food-sensing and satiety role for mammalian Nrf proteins.
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Affiliation(s)
| | | | - Alexander Howard
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Ian Brown
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Marina Ezcurra
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Ziyun Wu
- Joslin Diabetes Center, One Joslin Place, Boston, Massachusetts, United States of America
| | | | | | - Timo Kuerten
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - David Weinkove
- Magnitude Biosciences Ltd, NETPark Plexus, Sedgefield, United Kingdom
| | - T. Keith Blackwell
- Joslin Diabetes Center, One Joslin Place, Boston, Massachusetts, United States of America
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12
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Li Q, Marcu DC, Palazzo O, Turner F, King D, Spires-Jones TL, Stefan MI, Busch KE. High neural activity accelerates the decline of cognitive plasticity with age in Caenorhabditis elegans. eLife 2020; 9:59711. [PMID: 33228848 PMCID: PMC7685709 DOI: 10.7554/elife.59711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022] Open
Abstract
The ability to learn progressively declines with age. Neural hyperactivity has been implicated in impairing cognitive plasticity with age, but the molecular mechanisms remain elusive. Here, we show that chronic excitation of the Caenorhabditis elegans O2-sensing neurons during ageing causes a rapid decline of experience-dependent plasticity in response to environmental O2 concentration, whereas sustaining lower activity of O2-sensing neurons retains plasticity with age. We demonstrate that neural activity alters the ageing trajectory in the transcriptome of O2-sensing neurons, and our data suggest that high-activity neurons redirect resources from maintaining plasticity to sustaining continuous firing. Sustaining plasticity with age requires the K+-dependent Na+/Ca2+ (NCKX) exchanger, whereas the decline of plasticity with age in high-activity neurons acts through calmodulin and the scaffold protein Kidins220. Our findings demonstrate directly that the activity of neurons alters neuronal homeostasis to govern the age-related decline of neural plasticity and throw light on the mechanisms involved.
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Affiliation(s)
- Qiaochu Li
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel-Cosmin Marcu
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ottavia Palazzo
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Frances Turner
- Edinburgh Genomics (Genome Science), Ashworth Laboratories, The University of Edinburgh, Edinburgh, United Kingdom
| | - Declan King
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Melanie I Stefan
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,ZJU-UoE Institute, Zhejiang University, Haining, China
| | - Karl Emanuel Busch
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
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13
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Abstract
For the first 25 years after the landmark 1974 paper that launched the field, most C. elegans biologists were content to think of their subjects as solitary creatures. C. elegans presented no shortage of fascinating biological problems, but some of the features that led Brenner to settle on this species-in particular, its free-living, self-fertilizing lifestyle-also seemed to reduce its potential for interesting social behavior. That perspective soon changed, with the last two decades bringing remarkable progress in identifying and understanding the complex interactions between worms. The growing appreciation that C. elegans behavior can only be meaningfully understood in the context of its ecology and evolution ensures that the coming years will see similarly exciting progress.
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Affiliation(s)
- Douglas S Portman
- Departments of Biomedical Genetics, Neuroscience, and Biology, Del Monte Institute for Neuroscience, University of Rochester, Rochester, NY, USA
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14
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Abstract
Caenorhabditis elegans secretes a complex cocktail of small chemicals collectively called ascaroside pheromones which serves as a chemical language for intra-species communication. Subsets of ascarosides have been shown to mediate a broad spectrum of C. elegans behavior and development, such as gender-specific attraction, repulsion, aggregation, olfactory plasticity, and dauer formation. Recent studies show that specific components of ascarosides elicit a rapid avoidance response that allows animals to avoid predators and escape from unfavorable conditions. Moreover, this avoidance behavior is modulated by external conditions, internal states, and previous experience, indicating that pheromone avoidance behavior is highly plastic. In this review, we describe molecular and circuit mechanisms underlying plasticity in pheromone avoidance behavior which pave a way to better understanding circuit mechanisms underlying behavioral plasticity in higher animals, including humans.
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Affiliation(s)
- YongJin Cheon
- Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
| | - Hyeonjeong Hwang
- Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
| | - Kyuhyung Kim
- Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea.,Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
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15
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Takeishi A, Takagaki N, Kuhara A. Temperature signaling underlying thermotaxis and cold tolerance in Caenorhabditis elegans. J Neurogenet 2020; 34:351-362. [DOI: 10.1080/01677063.2020.1734001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Asuka Takeishi
- Neural Circuit of Multisensory Integration RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR), RIKEN Center for Brain Science (CBS), Wako, Japan
| | - Natsune Takagaki
- Graduate School of Natural Science, Konan University, Kobe, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Japan
| | - Atsushi Kuhara
- Graduate School of Natural Science, Konan University, Kobe, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo, Japan
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16
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Banerjee N, Hallem EA. Decoding Inter-individual Variability in Experience-Dependent Behavioral Plasticity. Neuron 2020; 105:7-9. [PMID: 31951528 DOI: 10.1016/j.neuron.2019.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Inter-individual variability in behavioral flexibility is widespread throughout the animal kingdom, but its underlying mechanisms remain poorly understood. In this issue of Neuron, Beets et al. (2020) provide novel insights into the genetic basis of inter-individual differences in behavioral flexibility using the model nematode C. elegans.
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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
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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17
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Beets I, Zhang G, Fenk LA, Chen C, Nelson GM, Félix MA, de Bono M. Natural Variation in a Dendritic Scaffold Protein Remodels Experience-Dependent Plasticity by Altering Neuropeptide Expression. Neuron 2019; 105:106-121.e10. [PMID: 31757604 PMCID: PMC6953435 DOI: 10.1016/j.neuron.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 08/18/2019] [Accepted: 09/28/2019] [Indexed: 12/13/2022]
Abstract
The extent to which behavior is shaped by experience varies between individuals. Genetic differences contribute to this variation, but the neural mechanisms are not understood. Here, we dissect natural variation in the behavioral flexibility of two Caenorhabditis elegans wild strains. In one strain, a memory of exposure to 21% O2 suppresses CO2-evoked locomotory arousal; in the other, CO2 evokes arousal regardless of previous O2 experience. We map that variation to a polymorphic dendritic scaffold protein, ARCP-1, expressed in sensory neurons. ARCP-1 binds the Ca2+-dependent phosphodiesterase PDE-1 and co-localizes PDE-1 with molecular sensors for CO2 at dendritic ends. Reducing ARCP-1 or PDE-1 activity promotes CO2 escape by altering neuropeptide expression in the BAG CO2 sensors. Variation in ARCP-1 alters behavioral plasticity in multiple paradigms. Our findings are reminiscent of genetic accommodation, an evolutionary process by which phenotypic flexibility in response to environmental variation is reset by genetic change. Behavioral flexibility varies across Caenorhabditis and C. elegans wild isolates A natural polymorphism in ARCP-1 underpins inter-individual variation in plasticity ARCP-1 is a dendritic scaffold protein localizing cGMP signaling machinery to cilia Disrupting ARCP-1 alters behavioral plasticity by changing neuropeptide expression
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Affiliation(s)
- Isabel Beets
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Gaotian Zhang
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France
| | - Lorenz A Fenk
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Changchun Chen
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Geoffrey M Nelson
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France.
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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18
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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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19
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Abstract
PRACTICAL RELEVANCE Cats are one of the most common companion animals in the world. However, relatively little scientific research has been conducted on cat behavior. With problem behaviors a leading reason for relinquishment of cats to shelters, or abandonment outdoors, solutions to address feline behavioral problems can have important welfare benefits. Because naturally occurring pheromones produce measurable species-specific responses in cats, the use of synthetic pheromone products consisting of the same compounds may activate a specific behavioral response in the receiving individual, allowing humans to better communicate with cats and manage feline problem behavior. AIMS In this article the scientific background for naturally occurring feline pheromones and semiochemicals and their impact on cat behavior is reviewed. This is used as a foundation to explore the three feline synthetic pheromones currently available and the empirical evidence that exists for their effectiveness. From this information, several recommendations for veterinarians and behavior professionals on the application of feline pheromone therapy in the home and veterinary clinic setting are presented. EVIDENCE BASE The efficacy of synthetic pheromones as a tool for the management of problem behaviors is a relatively new area of research and only fairly recently has the need to implement more rigorous research methodology been recognized.
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20
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Ascaroside Pheromones: Chemical Biology and Pleiotropic Neuronal Functions. Int J Mol Sci 2019; 20:ijms20163898. [PMID: 31405082 PMCID: PMC6719183 DOI: 10.3390/ijms20163898] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/1970] [Revised: 07/26/2019] [Accepted: 08/07/2019] [Indexed: 12/21/2022] Open
Abstract
Pheromones are neuronal signals that stimulate conspecific individuals to react to environmental stressors or stimuli. Research on the ascaroside (ascr) pheromones in Caenorhabditis elegans and other nematodes has made great progress since ascr#1 was first isolated and biochemically defined in 2005. In this review, we highlight the current research on the structural diversity, biosynthesis, and pleiotropic neuronal functions of ascr pheromones and their implications in animal physiology. Experimental evidence suggests that ascr biosynthesis starts with conjugation of ascarylose to very long-chain fatty acids that are then processed via peroxisomal β-oxidation to yield diverse ascr pheromones. We also discuss the concentration and stage-dependent pleiotropic neuronal functions of ascr pheromones. These functions include dauer induction, lifespan extension, repulsion, aggregation, mating, foraging and detoxification, among others. These roles are carried out in coordination with three G protein-coupled receptors that function as putative pheromone receptors: SRBC-64/66, SRG-36/37, and DAF-37/38. Pheromone sensing is transmitted in sensory neurons via DAF-16-regulated glutamatergic neurotransmitters. Neuronal peroxisomal fatty acid β-oxidation has important cell-autonomous functions in the regulation of neuroendocrine signaling, including neuroprotection. In the future, translation of our knowledge of nematode ascr pheromones to higher animals might be beneficial, as ascr#1 has some anti-inflammatory effects in mice. To this end, we propose the establishment of pheromics (pheromone omics) as a new subset of integrated disciplinary research area within chemical ecology for system-wide investigation of animal pheromones.
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21
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Okahata M, Wei AD, Ohta A, Kuhara A. Cold acclimation via the KQT-2 potassium channel is modulated by oxygen in Caenorhabditis elegans. SCIENCE ADVANCES 2019; 5:eaav3631. [PMID: 30775442 PMCID: PMC6365114 DOI: 10.1126/sciadv.aav3631] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Adaptive responses to external temperatures are essential for survival in changing environments. We show here that environmental oxygen concentration affects cold acclimation in Caenorhabditis elegans and that this response is regulated by a KCNQ-type potassium channel, KQT-2. Depending on culture conditions, kqt-2 mutants showed supranormal cold acclimation, caused by abnormal thermosensation in ADL chemosensory neurons. ADL neurons are responsive to temperature via transient receptor potential channels-OSM-9, OCR-2, and OCR-1-with OCR-1 negatively regulating ADL function. Similarly, KQT-2 and KQT-3 regulate ADL activity, with KQT-2 positively regulating ADL function. Abnormal cold acclimation and acute temperature responses of ADL neurons in kqt-2 mutants were suppressed by an oxygen-receptor mutation in URX coelomic sensory neurons, which are electrically connected to ADL via RMG interneurons. Likewise, low oxygen suppressed supranormal kqt-2 cold acclimation. These data thus demonstrate a simple neuronal circuit integrating two different sensory modalities, temperature and oxygen, that determines cold acclimation.
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Affiliation(s)
- Misaki Okahata
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
| | - Aguan D. Wei
- Center for Integrative Brain Research, Seattle Children’s Research Institute, 1900 Ninth Ave., Seattle, WA 98101, USA
| | - Akane Ohta
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe 658-8501, Japan
- Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Atsushi Kuhara
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe 658-8501, Japan
- Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo 100-0004, Japan
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22
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Feeding state sculpts a circuit for sensory valence in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2019; 116:1776-1781. [PMID: 30651312 DOI: 10.1073/pnas.1807454116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hunger affects the behavioral choices of all animals, and many chemosensory stimuli can be either attractive or repulsive depending on an animal's hunger state. Although hunger-induced behavioral changes are well documented, the molecular and cellular mechanisms by which hunger modulates neural circuit function to generate changes in chemosensory valence are poorly understood. Here, we use the CO2 response of the free-living nematode Caenorhabditis elegans to elucidate how hunger alters valence. We show that CO2 response valence shifts from aversion to attraction during starvation, a change that is mediated by two pairs of interneurons in the CO2 circuit, AIY and RIG. The transition from aversion to attraction is regulated by biogenic amine signaling. Dopamine promotes CO2 repulsion in well-fed animals, whereas octopamine promotes CO2 attraction in starved animals. Biogenic amines also regulate the temporal dynamics of the shift from aversion to attraction such that animals lacking octopamine show a delayed shift to attraction. Biogenic amine signaling regulates CO2 response valence by modulating the CO2-evoked activity of AIY and RIG. Our results illuminate a new role for biogenic amine signaling in regulating chemosensory valence as a function of hunger state.
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23
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Guo M, Ge M, Berberoglu MA, Zhou J, Ma L, Yang J, Dong Q, Feng Y, Wu Z, Dong Z. Dissecting Molecular and Circuit Mechanisms for Inhibition and Delayed Response of ASI Neurons during Nociceptive Stimulus. Cell Rep 2018; 25:1885-1897.e9. [PMID: 30428355 DOI: 10.1016/j.celrep.2018.10.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/05/2018] [Accepted: 10/17/2018] [Indexed: 10/27/2022] Open
Abstract
The mechanisms by which off-response neurons stay quiescent during stimulation are largely unknown. Here, we dissect underlying molecular and circuit mechanisms for the inhibition of off-response ASI neurons during nociceptive Cu2+ stimulation. ASIs are inhibited in parallel by sensory neurons ASER, ADFs, and ASHs. ASER activates RIC interneurons that release octopamine (OA) to inhibit ASIs through SER-3 and SER-6 receptors. ADFs release 5-HT that acts on the SER-1 receptor to activate RICs and subsequently inhibit ASIs. Furthermore, it is an inherent property of ASIs that only a delayed on response is evoked by Cu2+ stimulation even when all inhibitory neurons are silenced. Ectopic expression of the ion channel OCR-2, which functions synergistically with OSM-9, in the cilia of ASIs can induce an immediate on response of ASIs upon Cu2+ stimulation. Our findings elucidate the molecular and circuit mechanisms regulating fundamental properties of ASIs, including their inhibition and delayed response.
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Affiliation(s)
- Min Guo
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Minghai Ge
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Michael A Berberoglu
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jie Zhou
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Long Ma
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Juan Yang
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiyan Dong
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yanni Feng
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhengxing Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhiqiang Dong
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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24
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Zhao Y, Long L, Xu W, Campbell RF, Large EE, Greene JS, McGrath PT. Changes to social feeding behaviors are not sufficient for fitness gains of the Caenorhabditis elegans N2 reference strain. eLife 2018; 7:38675. [PMID: 30328811 PMCID: PMC6224195 DOI: 10.7554/elife.38675] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022] Open
Abstract
The standard reference Caenorhabditis elegans strain, N2, has evolved marked behavioral changes in social feeding behavior since its isolation from the wild. We show that the causal, laboratory-derived mutations in two genes, npr-1 and glb-5, confer large fitness advantages in standard laboratory conditions. Using environmental manipulations that suppress social/solitary behavior differences, we show the fitness advantages of the derived alleles remained unchanged, suggesting selection on these alleles acted through pleiotropic traits. Transcriptomics, developmental timing, and food consumption assays showed that N2 animals mature faster, produce more sperm, and consume more food than a strain containing ancestral alleles of these genes regardless of behavioral strategies. Our data suggest that the pleiotropic effects of glb-5 and npr-1 are a consequence of changes to O2 -sensing neurons that regulate both aerotaxis and energy homeostasis. Our results demonstrate how pleiotropy can lead to profound behavioral changes in a popular laboratory model. Why do humans walk on two feet? And what makes us smarter than our ape ancestors? The answers to these questions, and countless others about the particular traits of any number of species, is often said to be natural selection – a process where genes that ensure the survival of a species are favored of others. But it is not always the answer. Other evolutionary forces, such as random changes to the frequency of certain gene variants, restrictions on the development of a certain trait and pleiotropy (where one gene influences other, seemingly unrelated traits) can also cause differences between species. Designing experiments to test whether a trait difference is due to natural selection or other factors is notoriously difficult. However, the humble nematode worm, Caenorhabditis elegans, has proven to be particularly useful in this respect. One subtype or strain of C. elegans with certain changes to its genes is used internationally as a ‘reference strain’, to ensure results between labs are comparable. This strain, N2, has been bred in the laboratory for hundreds of generations, isolated from its wild counterparts. N2 shows several differences in behavior from the wildtype, including its feeding habits. Wild C. elegans tend to feed together socially, whereas N2 prefers to feed alone. In 1998 and 2009, researchers – including some involved in the current study – have identified the genetic modifications responsible for this change in behavior. Now, Zhao et al. set out to determine whether this was due to natural selection, and if so, was there a benefit to solitary feeding in laboratory conditions that was driving this genetic change? Zhao et al. found that the genetic changes in the N2 strain gave the worms a considerable advantage in the artificial environment. However, experiments to modify the conditions the animals grew in revealed that the solitary feeding habits were not necessary for the fitness advantage. In other words, the changes in feeding habits were a symptom of the genetic changes that gave N2 a selective advantage, but they were not the cause. In other words, the changes in feeding behavior were not a result of natural selection, but rather of pleiotropy. The findings highlight that not every change in a trait is down to natural selection and must therefore be put to the test. With declining costs of DNA sequencing, researchers can now easily identify genes and regions of DNA that are likely to be under selection. However, they must be careful before leaping to the conclusion that behavioral differences linked to genetic changes are adaptive. In addition, the findings show that the laboratories relying on N2 as a model organism should be aware that the strain has evolved fundamental differences in its brain connections compared with the wildtype.
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Affiliation(s)
- Yuehui Zhao
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
| | - Lijiang Long
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
| | - Wen Xu
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
| | - Richard F Campbell
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
| | - Edward E Large
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
| | | | - Patrick T McGrath
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, United States.,Department of Physics, Georgia Institute of Technology, Atlanta, United States.,Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, United States
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25
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McGrath PT, Ruvinsky I. A primer on pheromone signaling in Caenorhabditis elegans for systems biologists. ACTA ACUST UNITED AC 2018; 13:23-30. [PMID: 30984890 DOI: 10.1016/j.coisb.2018.08.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Individuals communicate information about their age, sex, social status, and recent life history with other members of their species through the release of pheromones, chemical signals that elicit behavioral or physiological changes in the recipients. Pheromones provide a fascinating example of information exchange: animals have evolved intraspecific languages in the presence of eavesdroppers and cheaters. In this review, we discuss the recent work using the nematode C. elegans to decipher its chemical language through the analysis of ascaroside pheromones. Genetic dissection has started to identify the enzymes that produce pheromones and the neural circuits that process these signals. Ecological experiments have characterized the biotic environment of C. elegans and its relatives, including ecological relationships with a variety of species that sense or release similar blends of ascarosides. Systems biology approaches should be fruitful in understanding the organization and function of communication systems in C. elegans.
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Affiliation(s)
- Patrick T McGrath
- Department of Biological Sciences, Department of Physics; Georgia Institute of Technology, Atlanta, GA 30332.
| | - Ilya Ruvinsky
- Department of Molecular Biosciences; Northwestern University, Evanston, IL 60208.
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26
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Fagan KA, Luo J, Lagoy RC, Schroeder FC, Albrecht DR, Portman DS. A Single-Neuron Chemosensory Switch Determines the Valence of a Sexually Dimorphic Sensory Behavior. Curr Biol 2018; 28:902-914.e5. [PMID: 29526590 PMCID: PMC5862148 DOI: 10.1016/j.cub.2018.02.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/11/2018] [Accepted: 02/14/2018] [Indexed: 01/08/2023]
Abstract
Biological sex, a fundamental dimension of internal state, can modulate neural circuits to generate behavioral variation. Understanding how and why circuits are tuned by sex can provide important insights into neural and behavioral plasticity. Here we find that sexually dimorphic behavioral responses to C. elegans ascaroside sex pheromones are implemented by the functional modulation of shared chemosensory circuitry. In particular, the sexual state of a single sensory neuron pair, ADF, determines the nature of an animal's behavioral response regardless of the sex of the rest of the body. Genetic feminization of ADF causes males to be repelled by, rather than attracted to, ascarosides, whereas masculinization of ADF has the opposite effect in hermaphrodites. When ADF is ablated, both sexes are weakly repelled by ascarosides. Genetic sex modulates ADF function by tuning chemosensation: although ADF is functional in both sexes, it detects the ascaroside ascr#3 only in males, a consequence of cell-autonomous action of the master sexual regulator tra-1. This occurs in part through the conserved DM-domain gene mab-3, which promotes the male state of ADF. The sexual modulation of ADF has a key role in reproductive fitness, as feminization or ablation of ADF renders males unable to use ascarosides to locate mates. Our results reveal an economical mechanism in which sex-specific behavioral valence arises through the cell-autonomous regulation of a chemosensory switch by genetic sex, allowing a social cue with salience for both sexes to elicit navigational responses commensurate with the differing needs of each.
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Affiliation(s)
- Kelli A Fagan
- Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA
| | - Jintao Luo
- Del Monte Institute for Neuroscience, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Center for Neurotherapeutics Development, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA
| | - Ross C Lagoy
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott Street, Room 4004, Worcester, MA 01605, USA
| | | | - Dirk R Albrecht
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott Street, Room 4004, Worcester, MA 01605, USA
| | - Douglas S Portman
- Del Monte Institute for Neuroscience, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Center for Neurotherapeutics Development, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Departments of Biomedical Genetics, Neuroscience, and Biology, University of Rochester, 601 Elmwood Avenue, Box 645, Rochester, NY 14610, USA.
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Barr MM, García LR, Portman DS. Sexual Dimorphism and Sex Differences in Caenorhabditis elegans Neuronal Development and Behavior. Genetics 2018; 208:909-935. [PMID: 29487147 PMCID: PMC5844341 DOI: 10.1534/genetics.117.300294] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/05/2018] [Indexed: 01/05/2023] Open
Abstract
As fundamental features of nearly all animal species, sexual dimorphisms and sex differences have particular relevance for the development and function of the nervous system. The unique advantages of the nematode Caenorhabditis elegans have allowed the neurobiology of sex to be studied at unprecedented scale, linking ultrastructure, molecular genetics, cell biology, development, neural circuit function, and behavior. Sex differences in the C. elegans nervous system encompass prominent anatomical dimorphisms as well as differences in physiology and connectivity. The influence of sex on behavior is just as diverse, with biological sex programming innate sex-specific behaviors and modifying many other aspects of neural circuit function. The study of these differences has provided important insights into mechanisms of neurogenesis, cell fate specification, and differentiation; synaptogenesis and connectivity; principles of circuit function, plasticity, and behavior; social communication; and many other areas of modern neurobiology.
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Affiliation(s)
- Maureen M Barr
- Department of Genetics, Rutgers University, Piscataway, New Jersey 08854-8082
| | - L Rene García
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Douglas S Portman
- Department of Biomedical Genetics, University of Rochester, New York 14642
- Department of Neuroscience, University of Rochester, New York 14642
- Department of Biology, University of Rochester, New York 14642
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Rouse T, Aubry G, Cho Y, Zimmer M, Lu H. A programmable platform for sub-second multichemical dynamic stimulation and neuronal functional imaging in C. elegans. LAB ON A CHIP 2018; 18:505-513. [PMID: 29313542 PMCID: PMC5790607 DOI: 10.1039/c7lc01116d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Caenorhabditis elegans (C. elegans) is a prominent model organism in neuroscience, as its small stereotyped nervous system offers unique advantages for studying neuronal circuits at the cellular level. Characterizing temporal dynamics of neuronal circuits is essential to fully understand neuronal processing. Characterization of the temporal dynamics of chemosensory circuits requires a precise and fast method to deliver multiple stimuli and monitor the animal's neuronal activity. Microfluidic platforms have been developed that offer an improved control of chemical delivery compared to manual methods. However, stimulating an animal with multiple chemicals at high speed is still difficult. In this work, we have developed a platform that can deliver any sequence of multiple chemical reagents, at sub-second resolution and without cross-contamination. We designed a network of chemical selectors wherein the chemical selected for stimulation is determined by the set of pressures applied to the chemical reservoirs. Modulation of inlet pressures has been automated to create robust, programmable sequences of subsecond chemical pulses. We showed that stimulation with sequences of different chemicals at the second to sub-second range can generate different neuronal activity patterns in chemosensory neurons; we observed previously unseen neuronal responses to a controlled chemical stimulation. Because of the speed and versatility of stimulus generated, this platform opens new possibilities to investigate neuronal circuits.
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Affiliation(s)
- T Rouse
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332, USA.
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