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Guo K, Huang Z, Wang C, Liu X, Chen Y, Fang J, Jin W, Xu J, Wu F, Zhou X. Nematicidal effects of silencing arginine kinase in the pine wood nematode, Bursaphelenchus xylophilus, determined using a dsRNA-like siRNA assembly. Int J Biol Macromol 2024; 279:135401. [PMID: 39245109 DOI: 10.1016/j.ijbiomac.2024.135401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 09/04/2024] [Accepted: 09/05/2024] [Indexed: 09/10/2024]
Abstract
The pine wood nematode Bursaphelenchus xylophilus is a highly invasive species responsible for the widespread pine wilt disease. Double-stranded RNA (dsRNA) biopesticides represent a novel strategy for controlling plant-parasitic nematodes. The B. xylophilus arginine kinase (BxAK) features a conserved ATP-binding domain and exhibits nematode-specific divergence in the phylogenetic tree. Notably, whole-mount in situ hybridization signals are evident in the nematode head and middle sections, particularly in the juvenile stage before sex differentiation. In this study, we developed a novel dsRNA-like small interfering RNA (siRNA) assembly that specifically targets BxAK and presents highly nematicidal effects. The RNA interference (RNAi) efficiency achieved a 95.9 % reduction in second-stage juveniles. In bioassays, the median lethal concentrations of this siRNA assembly against B. xylophilus were 168.5 ng/μl for juveniles and 603.8 ng/μl for adults within 48 h. Moreover, transcriptomic results revealed significantly downregulated expression levels of genes related to metabolism and development, suggesting that the mode of action of BxAK silencing is related to disruptions in energy homeostasis and juvenile development. In conclusion, BxAK is a molecular target for controlling B. xylophilus, and our siRNA assembly significantly enhances RNAi efficiency and lowers the lethal concentration required, making it a promising candidate for future biocontrol applications.
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Affiliation(s)
- Kai Guo
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Ziqian Huang
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Chunyu Wang
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Xuemeng Liu
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Ye Chen
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Jiadi Fang
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Weibo Jin
- Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Jinfeng Xu
- Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Fangli Wu
- Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China.
| | - Xiang Zhou
- State key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China.
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2
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Watteyne J, Chudinova A, Ripoll-Sánchez L, Schafer WR, Beets I. Neuropeptide signaling network of Caenorhabditis elegans: from structure to behavior. Genetics 2024:iyae141. [PMID: 39344922 DOI: 10.1093/genetics/iyae141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 08/19/2024] [Indexed: 10/01/2024] Open
Abstract
Neuropeptides are abundant signaling molecules that control neuronal activity and behavior in all animals. Owing in part to its well-defined and compact nervous system, Caenorhabditis elegans has been one of the primary model organisms used to investigate how neuropeptide signaling networks are organized and how these neurochemicals regulate behavior. We here review recent work that has expanded our understanding of the neuropeptidergic signaling network in C. elegans by mapping the evolutionary conservation, the molecular expression, the receptor-ligand interactions, and the system-wide organization of neuropeptide pathways in the C. elegans nervous system. We also describe general insights into neuropeptidergic circuit motifs and the spatiotemporal range of peptidergic transmission that have emerged from in vivo studies on neuropeptide signaling. With efforts ongoing to chart peptide signaling networks in other organisms, the C. elegans neuropeptidergic connectome can serve as a prototype to further understand the organization and the signaling dynamics of these networks at organismal level.
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Affiliation(s)
- Jan Watteyne
- Department of Biology, University of Leuven, Leuven 3000, Belgium
| | | | - Lidia Ripoll-Sánchez
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
- Department of Psychiatry, Cambridge University, Cambridge CB2 0SZ, UK
| | - William R Schafer
- Department of Biology, University of Leuven, Leuven 3000, Belgium
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Isabel Beets
- Department of Biology, University of Leuven, Leuven 3000, Belgium
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3
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Kwon Y, Kim J, Son YB, Lee SA, Choi SS, Cho Y. Advanced Neural Functional Imaging in C. elegans Using Lab-on-a-Chip Technology. MICROMACHINES 2024; 15:1027. [PMID: 39203678 PMCID: PMC11356251 DOI: 10.3390/mi15081027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 08/05/2024] [Accepted: 08/06/2024] [Indexed: 09/03/2024]
Abstract
The ability to perceive and adapt to environmental changes is crucial for the survival of all organisms. Neural functional imaging, particularly in model organisms, such as Caenorhabditis elegans, provides valuable insights into how animals sense and process external cues through their nervous systems. Because of its fully mapped neural anatomy, transparent body, and genetic tractability, C. elegans serves as an ideal model for these studies. This review focuses on advanced methods for neural functional imaging in C. elegans, highlighting calcium imaging techniques, lab-on-a-chip technologies, and their applications in the study of various sensory modalities, including chemosensation, mechanosensation, thermosensation, photosensation, and magnetosensation. We discuss the benefits of these methods in terms of precision, reproducibility, and ability to study dynamic neural processes in real time, ultimately advancing our understanding of the fundamental principles of neural activity and connectivity.
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Affiliation(s)
- Youngeun Kwon
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Jihye Kim
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Ye Bin Son
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Sol Ah Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | - Shin Sik Choi
- Department of Bio-Pharmaceutical Sciences, Myongji University, Yongin 17058, Republic of Korea;
- The Natural Science Research Institute, Department of Food and Nutrition, Myongji University, Yongin 17058, Republic of Korea
- elegslab Inc., Seoul 06083, Republic of Korea
| | - Yongmin Cho
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
- elegslab Inc., Seoul 06083, Republic of Korea
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4
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Pop M, Klemke AL, Seidler L, Wernet N, Steudel PL, Baust V, Wohlmann E, Fischer R. Caenorhabditis elegans neuropeptide NLP-27 enhances neurodegeneration and paralysis in an opioid-like manner during fungal infection. iScience 2024; 27:109484. [PMID: 38784855 PMCID: PMC11112505 DOI: 10.1016/j.isci.2024.109484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 10/26/2023] [Accepted: 03/08/2024] [Indexed: 05/25/2024] Open
Abstract
The nervous system of metazoans is involved in host-pathogen interactions to control immune activation. In Caenorhabditis elegans, this includes sleep induction, mediated by neuropeptide-like proteins (NLPs), which increases the chance of survival after wounding. Here we analyzed the role of NLP-27 in the infection of C. elegans with the nematode-trapping fungus Arthrobotrys flagrans. Early responses of C. elegans were the upregulation of nlp-27, the induction of paralysis (sleep), and neurodegeneration of the mechanosensing PVD (Posterior Ventral Process D) neurons. Deletion of nlp-27 reduced neurodegeneration during fungal attack. Induction of nlp-27 was independent of the MAP kinase PMK-1, and expression of nlp-27 in the hypodermis was sufficient to induce paralysis, although NLP-27 was also upregulated in head neurons. NLP-27 contains the pentapeptide YGGYG sequence known to bind the human μ- and κ-type opioid receptors suggesting NLP-27 or peptides thereof act on opioid receptors. The opioid receptor antagonist naloxone shortened the paralysis time like overexpression of NLP-27.
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Affiliation(s)
- Maria Pop
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Anna-Lena Klemke
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Lena Seidler
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Nicole Wernet
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Pietrina Loredana Steudel
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Vanessa Baust
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Elke Wohlmann
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany
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5
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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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6
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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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7
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Du H, Wang R, Dai X, Yin Z, Liu Y, Su L, Chen H, Zhao S, Zheng L, Dong X, Zhai Y. Effect of Guanylate Cyclase-22-like on Ovarian Development of Orius nagaii (Hemiptera: Anthocoridae). INSECTS 2024; 15:110. [PMID: 38392529 PMCID: PMC10889437 DOI: 10.3390/insects15020110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/24/2024]
Abstract
This study identified and characterized the gene encoding recep tor-type guanylate cyclase-22-like (GCY-22; OnGCY) from the pirate bug Orius nagaii, an important biological control agent. The full-length cDNA of the GCY of O. nagaii was obtained by rapid amplification of cDNA ends (RACE); it had a total length of 4888 base pairs (bp), of which the open reading frame (ORF) was 3750 bp, encoding a polypeptide of 1249 amino acid residues. The physicochemical properties of OnGCY were predicted and analyzed by using relevant ExPASy software, revealing a molecular formula of C6502H10122N1698O1869S57, molecular weight of ~143,811.57 kDa, isoelectric point of 6.55, and fat index of 90.04. The resulting protein was also shown to have a signal peptide, two transmembrane regions, and a conserved tyrosine kinase (tyrkc). Silencing OnGCY by RNA interference significantly inhibited ovarian development and decreased fertility in female O. nagaii in the treated versus the control group. Additionally, OnGCY silencing significantly decreased the expression levels of other GCY and Vg genes. Thus, these results clarify the structure and biological function of OnGCY, which has an important role in insect fecundity. The results also provide a reference for agricultural pest control and future large-scale breeding of biological control agents.
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Affiliation(s)
- Huiling Du
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-Construction by Ministry and Province), College of Agriculture, Yangtze University, Jingzhou 434025, China
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Ruijuan Wang
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Xiaoyan Dai
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Zhenjuan Yin
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Yan Liu
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Long Su
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Hao Chen
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Shan Zhao
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Li Zheng
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
| | - Xiaolin Dong
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-Construction by Ministry and Province), College of Agriculture, Yangtze University, Jingzhou 434025, China
| | - Yifan Zhai
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences, 23788 Gongye North Road, Jinan 250100, China
- Key Laboratory of Natural Enemies Insects, Ministry of Agriculture and Rural Affairs, Jinan 250100, China
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8
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Bryant AS, Akimori D, Stoltzfus JDC, Hallem EA. A standard workflow for community-driven manual curation of Strongyloides genome annotations. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220443. [PMID: 38008112 PMCID: PMC10676816 DOI: 10.1098/rstb.2022.0443] [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: 03/14/2023] [Accepted: 07/18/2023] [Indexed: 11/28/2023] Open
Abstract
Advances in the functional genomics and bioinformatics toolkits for Strongyloides species have positioned these species as genetically tractable model systems for gastrointestinal parasitic nematodes. As community interest in mechanistic studies of Strongyloides species continues to grow, publicly accessible reference genomes and associated genome annotations are critical resources for researchers. Genome annotations for multiple Strongyloides species are broadly available via the WormBase and WormBase ParaSite online repositories. However, a recent phylogenetic analysis of the receptor-type guanylate cyclase (rGC) gene family in two Strongyloides species highlights the potential for errors in a large percentage of current Strongyloides gene models. Here, we present three examples of gene annotation updates within the Strongyloides rGC gene family; each example illustrates a type of error that may occur frequently within the annotation data for Strongyloides genomes. We also extend our analysis to 405 previously curated Strongyloides genes to confirm that gene model errors are found at high rates across gene families. Finally, we introduce a standard manual curation workflow for assessing gene annotation quality and generating corrections, and we discuss how it may be used to facilitate community-driven curation of parasitic nematode biodata. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.
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Affiliation(s)
- Astra S. Bryant
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Damia Akimori
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Interdepartmental PhD Program, 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
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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9
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Liao CP, Chiang YC, Tam WH, Chen YJ, Chou SH, Pan CL. Neurophysiological basis of stress-induced aversive memory in the nematode Caenorhabditis elegans. Curr Biol 2022; 32:5309-5322.e6. [PMID: 36455561 DOI: 10.1016/j.cub.2022.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/01/2022] [Accepted: 11/04/2022] [Indexed: 12/03/2022]
Abstract
Physiological stress induces aversive memory formation and profoundly impacts animal behavior. In C. elegans, concurrent mitochondrial disruption induces aversion to the bacteria that the animal inherently prefers, offering an experimental paradigm for studying the neural basis of aversive memory. We find that, under mitochondrial stress, octopamine secreted from the RIC modulatory neuron targets the AIY interneuron through the SER-6 receptor to trigger learned bacterial aversion. RIC responds to systemic mitochondrial stress by increasing octopamine synthesis and acts in the formation of aversive memory. AIY integrates sensory information, acts downstream of RIC, and is important for the retrieval of aversive memory. Systemic mitochondrial dysfunction induces RIC responses to bacterial cues that parallel stress induction, suggesting that physiological stress activates latent communication between RIC and the sensory neurons. These findings provide insights into the circuit and neuromodulatory mechanisms underlying stress-induced aversive memory.
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Affiliation(s)
- Chien-Po Liao
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yueh-Chen Chiang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Wai Hou Tam
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yen-Ju Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Shih-Hua Chou
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan; Center for Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan.
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10
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Yoon KH, Indong RA, Lee JI. Making "Sense" of Ecology from a Genetic Perspective: Caenorhabditis elegans, Microbes and Behavior. Metabolites 2022; 12:1084. [PMID: 36355167 PMCID: PMC9697003 DOI: 10.3390/metabo12111084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 12/31/2023] Open
Abstract
Our knowledge of animal and behavior in the natural ecology is based on over a century's worth of valuable field studies. In this post-genome era, however, we recognize that genes are the underpinning of ecological interactions between two organisms. Understanding how genes contribute to animal ecology, which is essentially the intersection of two genomes, is a tremendous challenge. The bacterivorous nematode Caenorhabditis elegans, one of the most well-known genetic animal model experimental systems, experiences a complex microbial world in its natural habitat, providing us with a window into the interplay of genes and molecules that result in an animal-microbial ecology. In this review, we will discuss C. elegans natural ecology, how the worm uses its sensory system to detect the microbes and metabolites that it encounters, and then discuss some of the fascinating ecological dances, including behaviors, that have evolved between the nematode and the microbes in its environment.
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Affiliation(s)
- Kyoung-hye Yoon
- Department of Physiology, Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
| | - Rocel Amor Indong
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 26493, Korea
| | - Jin I. Lee
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 26493, Korea
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11
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Ren J, Sang Y, Aballay A. Cholinergic receptor-Wnt pathway controls immune activation by sensing intestinal dysfunction. Cell Rep 2022; 41:111575. [DOI: 10.1016/j.celrep.2022.111575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 09/09/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
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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: 9] [Impact Index Per Article: 4.5] [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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Aoki I, Jurado P, Nawa K, Kondo R, Yamashiro R, Matsuyama HJ, Ferrer I, Nakano S, Mori I. OLA-1, an Obg-like ATPase, integrates hunger with temperature information in sensory neurons in C. elegans. PLoS Genet 2022; 18:e1010219. [PMID: 35675262 PMCID: PMC9176836 DOI: 10.1371/journal.pgen.1010219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 04/26/2022] [Indexed: 11/18/2022] Open
Abstract
Animals detect changes in both their environment and their internal state and modify their behavior accordingly. Yet, it remains largely to be clarified how information of environment and internal state is integrated and how such integrated information modifies behavior. Well-fed C. elegans migrates to past cultivation temperature on a thermal gradient, which is disrupted when animals are starved. We recently reported that the neuronal activities synchronize between a thermosensory neuron AFD and an interneuron AIY, which is directly downstream of AFD, in well-fed animals, while this synchrony is disrupted in starved animals. However, it remained to be determined whether the disruption of the synchrony is derived from modulation of the transmitter release from AFD or from the modification of reception or signal transduction in AIY. By performing forward genetics on a transition of thermotaxis behavior along starvation, we revealed that OLA-1, an Obg-like ATPase, functions in AFD to promote disruption of AFD-AIY synchrony and behavioral transition. Our results suggest that the information of hunger is delivered to the AFD thermosensory neuron and gates transmitter release from AFD to disrupt thermotaxis, thereby shedding light onto a mechanism for the integration of environmental and internal state to modulate behavior.
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Affiliation(s)
- Ichiro Aoki
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Paola Jurado
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Cancer Area, Institut d’Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Kanji Nawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Rumi Kondo
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Riku Yamashiro
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Hironori J. Matsuyama
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Isidre Ferrer
- Neuroscience Area, Institut d’Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Shunji Nakano
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Ikue Mori
- Group of Molecular Neurobiology, Neuroscience Institute, Graduate School of Science, Nagoya University, Nagoya, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- * E-mail:
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14
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Riedl J, Fieseler C, Zimmer M. Tyraminergic corollary discharge filters reafferent perception in a chemosensory neuron. Curr Biol 2022; 32:3048-3058.e6. [PMID: 35690069 DOI: 10.1016/j.cub.2022.05.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 12/25/2022]
Abstract
Interpreting sensory information requires its integration with the current behavior of the animal. However, how motor-related circuits influence sensory information processing is incompletely understood. Here, we report that current locomotor state directly modulates the activity of BAG CO2 sensory neurons in Caenorhabditis elegans. By recording neuronal activity in animals freely navigating CO2 landscapes, we found that during reverse crawling states, BAG activity is suppressed by tyraminergic corollary discharge signaling. We provide genetic evidence that tyramine released from the RIM reversal interneurons extrasynaptically activates the inhibitory chloride channel LGC-55 in BAG. Disrupting this pathway genetically leads to excessive behavioral responses to CO2 stimuli. Moreover, we find that LGC-55 signaling cancels out perception of self-produced CO2 and O2 stimuli when animals reverse into their own gas plume in ethologically relevant aqueous environments. Our results show that sensorimotor integration involves corollary discharge signals directly modulating chemosensory neurons.
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Affiliation(s)
- Julia Riedl
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Charles Fieseler
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, Vienna BioCenter (VBC), University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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15
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Opponent vesicular transporters regulate the strength of glutamatergic neurotransmission in a C. elegans sensory circuit. Nat Commun 2021; 12:6334. [PMID: 34732711 PMCID: PMC8566550 DOI: 10.1038/s41467-021-26575-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/22/2021] [Indexed: 11/30/2022] Open
Abstract
At chemical synapses, neurotransmitters are packaged into synaptic vesicles that release their contents in response to depolarization. Despite its central role in synaptic function, regulation of the machinery that loads vesicles with neurotransmitters remains poorly understood. We find that synaptic glutamate signaling in a C. elegans chemosensory circuit is regulated by antagonistic interactions between the canonical vesicular glutamate transporter EAT-4/VGLUT and another vesicular transporter, VST-1. Loss of VST-1 strongly potentiates glutamate release from chemosensory BAG neurons and disrupts chemotaxis behavior. Analysis of the circuitry downstream of BAG neurons shows that excess glutamate release disrupts behavior by inappropriately recruiting RIA interneurons to the BAG-associated chemotaxis circuit. Our data indicate that in vivo the strength of glutamatergic synapses is controlled by regulation of neurotransmitter packaging into synaptic vesicles via functional coupling of VGLUT and VST-1. The authors describe a vesicular transporter, VST-1, that is required in glutamatergic chemosensory neurons for chemotactic avoidance behavior in C. elegans. VST-1 antagonizes VGLUT-dependent packaging of glutamate into synaptic vesicles and determines the strength of synaptic glutamate signaling.
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16
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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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17
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Chen C, Ma H, Fu Z. Antidepressant-like Effect of 3-n-Butylphthalide in Rats Exposed to Chronic Unpredictable Mild Stress: Modulation of Brain-Derived Neurotrophic Factor Level and mTOR Activation in Cortex. Neurochem Res 2021; 46:3075-3084. [PMID: 34374900 DOI: 10.1007/s11064-021-03397-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 07/03/2021] [Accepted: 07/06/2021] [Indexed: 12/28/2022]
Abstract
3-n-Butylphthalide (NBP), an extract from seeds of Apium graveolens Linn. (Chinese celery), has been demonstrated to have antidepressant effects in suspension chronic-stressed rats by our group. The purpose of this study was to investigate the possible involvement of brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the antidepressant mechanism of NBP. Chronic unpredictable mild stress (CUMS) was applied for 6 weeks to induced a depressive-like behavior, characterized by decreased locomotor activity, sucrose preference and the NE, DA and 5-HT levels in cortex. Oral treatment with NBP (30 or 100 mg/kg, p.o.), similarly to fluoxetine (2 mg/kg, p.o.), can prevention of these alterations. The NBP (30 or 100 mg/kg, p.o.) reversed the decrease in the BDNF, p-ERK, mTOR and synapsin-1 protein levels in rat cortex caused by CUMS. And rapamycin, an mTOR inhibitor, completely inhibited the antidepressant-like activity of NBP in vivo. In conclusion, these findings indicate that NBP treatment attenuated the depression-like behaviors through the modulation of serotonergic system and BDNF-ERK-mTOR signaling in rat.
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Affiliation(s)
- Chunlin Chen
- Chemistry and Biological Engineering Academy, Yichun University, Yichun, 336000, China.
| | - Hao Ma
- Aesthetic Medical School, Yichun University, Yichun, 336000, China
| | - Zhifeng Fu
- Chemistry and Biological Engineering Academy, Yichun University, Yichun, 336000, China
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18
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Wibisono P, Sun J. Neuro-immune communication in C. elegans defense against pathogen infection. CURRENT RESEARCH IN IMMUNOLOGY 2021; 2:60-65. [PMID: 34368754 PMCID: PMC8344176 DOI: 10.1016/j.crimmu.2021.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The innate immune system is a complex collection of physical barriers and physiological defense responses to internal and external environmental assaults. Recent studies in the model organism Caenorhabditis elegans have highlighted how the nervous system interacts with the innate immune system to generate coordinated protective responses. Indeed, studies on neuro-immune interaction pathways have provided mechanistic insights into the roles of neuro-immune communication in modulating both immune and behavioral responses to pathogen attacks. The nervous system releases a variety of neurotransmitters, peptides, and hormones that regulate the innate immune response, while the innate immune system also relays information to the nervous system to affect learning and behavioral responses. Although these interactions still need further investigation, the knowledge that we have gained thus far has improved our understanding of how separate biological systems can act collectively for the survival and well-being of an organism. Here, we review recent studies on neuro-immune communication related to the survival and defense of C. elegans against pathogens. Neuro-immune communication is essential for generating coordinated defense against pathogen infection to improve host survival. Neuro-immune communication modulates both immune and behavioral responses to pathogen attacks. C.elegans is an excellent model system for studying neuro-immune communication.
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Affiliation(s)
- Phillip Wibisono
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Jingru Sun
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
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19
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Park K, Li C, Tsiropoulou S, Gonçalves J, Kondratev C, Pelletier L, Blacque OE, Leroux MR. CDKL kinase regulates the length of the ciliary proximal segment. Curr Biol 2021; 31:2359-2373.e7. [PMID: 33857430 DOI: 10.1016/j.cub.2021.03.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/25/2021] [Accepted: 03/19/2021] [Indexed: 11/16/2022]
Abstract
Cilia are organelles found throughout most unicellular eukaryotes and different metazoan cell types. To accomplish their essential roles in cell motility, fluid flow, and signaling, cilia are divided into subcompartments with variable structures, compositions, and functions. How these specific subcompartments are built remains almost completely unexplored. Here, we show that C. elegans CDKL-1, related to the human CDKL kinase family (CDKL1/CDKL2/CDKL3/CDKL4/CDKL5), specifically controls the length of the proximal segment, a ciliary subdomain conserved in evolution from Tetrahymena motile cilia to C. elegans chemosensory, mammalian olfactory, and photoreceptor non-motile cilia. CDKL-1 associates with intraflagellar transport (IFT), influences the distribution of the IFT anterograde motors heterotrimeric kinesin-II and homodimeric OSM-3-kinesin/KIF17 in the proximal segment, and shifts the boundary between the proximal and distal segments (PS/DS boundary). CDKL-1 appears to function independently from several factors that influence cilium length, namely the kinases DYF-5 (mammalian CILK1/MAK) and NEKL-1 (NEK9), as well as the depolymerizing kinesins KLP-13 (KIF19) and KLP-7 (KIF2). However, a different kinase, DYF-18 (CCRK), is needed for the correct localization and function of CDKL-1 and similarly influences the length of the proximal segment. Loss of CDKL-1, which affects proximal segment length without impairing overall ciliary microtubule structural integrity, also impairs cilium-dependent processes, namely cGMP-signaling-dependent body length control and CO2 avoidance. Collectively, our findings suggest that cilium length is regulated by various pathways and that the IFT-associated kinase CDKL-1 is essential for the construction of a specific ciliary compartment and contributes to development and sensory physiology.
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Affiliation(s)
- Kwangjin Park
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - João Gonçalves
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Christine Kondratev
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Laurence Pelletier
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
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20
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Zhang X, Li L, Kesner L, Robert CAM. Chemical host-seeking cues of entomopathogenic nematodes. CURRENT OPINION IN INSECT SCIENCE 2021; 44:72-81. [PMID: 33866041 DOI: 10.1016/j.cois.2021.03.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Entomopathogenic nematodes (EPNs) are obligate parasites that infect a broad range of insect species. Host-seeking is a crucial step for EPN infection success and survival. Yet, the identity and ecological functions of chemicals involved in host-seeking by EPNs remain overlooked. In this review, we report known CO2, plant-derived and insect-derived cues shaping EPN host-seeking and recognition. Despite species-specific response to environmental cues, we highlight a hierarchical integration of chemicals by EPNs. We further emphasize the impact of EPN selection pressure, age, and experience on their responsiveness to infochemicals. Finally, we feature that EPN chemical ecology can translate into powerful sustainable strategies to control insect herbivores in agriculture.
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Affiliation(s)
- Xi Zhang
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China.
| | - Lu Li
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Lucie Kesner
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
| | - Christelle Aurélie Maud Robert
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland; Oeschger Centre for Climate Change Research (OCCR), University of Bern, Falkenplatz 16, 3012 Bern, Switzerland.
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21
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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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22
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Rossillo M, Ringstad N. Development of specialized sensory neurons engages a nuclear receptor required for functional plasticity. Genes Dev 2020; 34:1666-1679. [PMID: 33184226 PMCID: PMC7706712 DOI: 10.1101/gad.342212.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/30/2020] [Indexed: 12/12/2022]
Abstract
In this study, Rossillo and Ringstad sought to determine mechanisms that support the physiology and plasticity of BAG neurons, which are specialized neurons that sense the respiratory gas carbon dioxide (CO2) and, in a context-dependent manner, switch from mediating avoidance of CO2 to supporting CO2 attraction in C. elegans. They used tandem ChIP-seq and cell targeted RNA-seq to identify gene targets of the transcription factor ETS-5, which is required for BAG development, and their functional screen of ETS-5 targets revealed that NHR-6, the sole C. elegans NR4A-type nuclear receptor, is required for BAG-mediated avoidance of CO2 and regulates expression of a subset of BAG-specific genes. During development, the nervous system generates neurons that serve highly specialized roles and, accordingly, possess unique functional attributes. The chemosensory BAG neurons of C. elegans are striking exemplars of this. BAGs sense the respiratory gas carbon dioxide (CO2) and, in a context-dependent manner, switch from mediating avoidance of CO2 to supporting CO2 attraction. To determine mechanisms that support the physiology and plasticity of BAG neurons, we used tandem ChIP-seq and cell targeted RNA-seq to identify gene targets of the transcription factor ETS-5, which is required for BAG development. A functional screen of ETS-5 targets revealed that NHR-6, the sole C. elegans NR4A-type nuclear receptor, is required for BAG-mediated avoidance of CO2 and regulates expression of a subset of BAG-specific genes. Unlike ets-5 mutants, which are defective for both attraction to and avoidance of CO2, nhr-6 mutants are fully competent for attraction. These data indicate that the remarkable ability of BAGs to adaptively assign positive or negative valence to a chemosensory stimulus requires a gene-regulatory program supported by an evolutionarily conserved type of nuclear receptor. We suggest that NHR-6 might be an example of a developmental mechanism for modular encoding of functional plasticity in the nervous system.
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Affiliation(s)
- Mary Rossillo
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
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23
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Abstract
With a nervous system that has only a few hundred neurons, Caenorhabditis elegans was initially not regarded as a model for studies on learning. However, the collective effort of the C. elegans field in the past several decades has shown that the worm displays plasticity in its behavioral response to a wide range of sensory cues in the environment. As a bacteria-feeding worm, C. elegans is highly adaptive to the bacteria enriched in its habitat, especially those that are pathogenic and pose a threat to survival. It uses several common forms of behavioral plasticity that last for different amounts of time, including imprinting and adult-stage associative learning, to modulate its interactions with pathogenic bacteria. Probing the molecular, cellular and circuit mechanisms underlying these forms of experience-dependent plasticity has identified signaling pathways and regulatory insights that are conserved in more complex animals.
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Affiliation(s)
- He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
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24
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Elucidation and genetic intervention of CO2 concentration mechanism in Chlamydomonas reinhardtii for increased plant primary productivity. J Biosci 2020. [DOI: 10.1007/s12038-020-00080-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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25
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Baiocchi T, Anesko K, Mercado N, Park H, Kin K, Strickhouser-Monzon B, Robles P, Bowman C, Wang H, Sternberg PW, Dillman AR. Signaling by AWC Olfactory Neurons Is Necessary for Caenorhabditis elegans' Response to Prenol, an Odor Associated with Nematode-Infected Insects. Genetics 2020; 216:145-157. [PMID: 32680884 PMCID: PMC7463287 DOI: 10.1534/genetics.120.303280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022] Open
Abstract
Chemosensation plays a role in the behaviors and life cycles of numerous organisms, including nematodes. Many guilds of nematodes exist, ranging from the free-living Caenorhabditis elegans to various parasitic species such as entomopathogenic nematodes (EPNs), which are parasites of insects. Despite ecological differences, previous research has shown that both EPNs and C. elegans respond to prenol (3-methyl-2-buten-1-ol), an odor associated with EPN infections. However, it is unclear how C. elegans responds to prenol. By utilizing natural variation and genetic neuron ablation to investigate the response of C. elegans to prenol, we found that the AWC neurons are involved in the detection of prenol and that several genes (including dcap-1, dcap-2, and clec-39) influence response to this odorant. Furthermore, we identified that the response to prenol is mediated by the canonically proposed pathway required for other AWC-sensed attractants. However, upon testing genetically diverse isolates, we found that the response of some strains to prenol differed from their response to isoamyl alcohol, suggesting that the pathways mediating response to these two odorants may be genetically distinct. Further, evaluations leveraging natural variation and genome wide association revealed specific genes that influence nematode behavior and provide a foundation for future studies to better understand the role of prenol in nematode behavioral ecology.
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Affiliation(s)
- Tiffany Baiocchi
- Department of Nematology, University of California, Riverside, California 92521
| | - Kyle Anesko
- Department of Nematology, University of California, Riverside, California 92521
| | - Nathan Mercado
- Department of Nematology, University of California, Riverside, California 92521
| | - Heenam Park
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Kassandra Kin
- Department of Nematology, University of California, Riverside, California 92521
| | | | - Priscila Robles
- Department of Nematology, University of California, Riverside, California 92521
| | - Christian Bowman
- Department of Nematology, University of California, Riverside, California 92521
| | - Han Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Adler R Dillman
- Department of Nematology, University of California, Riverside, California 92521
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26
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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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27
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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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28
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Horowitz LB, Brandt JP, Ringstad N. Repression of an activity-dependent autocrine insulin signal is required for sensory neuron development in C. elegans. Development 2019; 146:dev.182873. [PMID: 31628111 DOI: 10.1242/dev.182873] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/14/2019] [Indexed: 11/20/2022]
Abstract
Nervous system development is instructed by genetic programs and refined by distinct mechanisms that couple neural activity to gene expression. How these processes are integrated remains poorly understood. Here, we report that the regulated release of insulin-like peptides (ILPs) during development of the Caenorhabditis elegans nervous system accomplishes such an integration. We find that the p38 MAP kinase PMK-3, which is required for the differentiation of chemosensory BAG neurons, limits an ILP signal that represses expression of a BAG neuron fate. ILPs are released from BAGs themselves in an activity-dependent manner during development, indicating that ILPs constitute an autocrine signal that regulates the differentiation of BAG neurons. Expression of a specialized neuronal fate is, therefore, coordinately regulated by a genetic program that sets levels of ILP expression during development, and by neural activity, which regulates ILP release. Autocrine signals of this kind might have general and conserved functions as integrators of deterministic genetic programs with activity-dependent mechanisms during neurodevelopment.
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Affiliation(s)
- Lauren Bayer Horowitz
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Julia P Brandt
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
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29
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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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30
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Hong RL, Riebesell M, Bumbarger DJ, Cook SJ, Carstensen HR, Sarpolaki T, Cochella L, Castrejon J, Moreno E, Sieriebriennikov B, Hobert O, Sommer RJ. Evolution of neuronal anatomy and circuitry in two highly divergent nematode species. eLife 2019; 8:47155. [PMID: 31526477 PMCID: PMC6748829 DOI: 10.7554/elife.47155] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/12/2019] [Indexed: 11/17/2022] Open
Abstract
The nematodes C. elegans and P. pacificus populate diverse habitats and display distinct patterns of behavior. To understand how their nervous systems have diverged, we undertook a detailed examination of the neuroanatomy of the chemosensory system of P. pacificus. Using independent features such as cell body position, axon projections and lipophilic dye uptake, we have assigned homologies between the amphid neurons, their first-layer interneurons, and several internal receptor neurons of P. pacificus and C. elegans. We found that neuronal number and soma position are highly conserved. However, the morphological elaborations of several amphid cilia are different between them, most notably in the absence of ‘winged’ cilia morphology in P. pacificus. We established a synaptic wiring diagram of amphid sensory neurons and amphid interneurons in P. pacificus and found striking patterns of conservation and divergence in connectivity relative to C. elegans, but very little changes in relative neighborhood of neuronal processes. These findings demonstrate the existence of several constraints in patterning the nervous system and suggest that major substrates for evolutionary novelty lie in the alterations of dendritic structures and synaptic connectivity. Nerve cells, also called neurons, are responsible both for sensing signals from the environment and for determining how organisms react. This means that the unique features of an animal’s nervous system underpin its characteristic behaviors. Comparing the anatomy of the nervous systems in different animals could therefore yield valuable insights into how structural and behavioral differences emerge over time. Behavioral variation often occurs even in similar-looking animals. One example is a group of microscopic worms, called nematodes. Although many nematode species exist, their overall body plans are the same, and the worms of each species contain a fixed number of cells. Despite these apparent similarities, different species of nematodes inhabit a variety of environments and may respond differently to the same signals. The main sensory organs in nematodes are called the amphid sensilla. They are used to detect chemicals, as well as other inputs from the environment such as temperature and pheromones from other nematodes. Although researchers have often speculated that the number of cells in these organs and their arrangement are broadly the same across species, their anatomy had not been studied in detail. Hong, Riebesell et al. compared the detailed structure and genetic features of the sensory systems in two distantly related species of nematode worms, Pristionchus pacificus and Caenorhabditis elegans. These two species behave in different ways, for example, P. pacificus is usually found in association with different species of beetles, while C. elegans is free-living and usually found on rotting fruit. By comparing the two, Hong, Riebesell et al. wanted to determine whether the diverse behaviors observed in the two species could be determined by differences between their sensory systems. Experiments using electron microscopy yielded several thousand high resolution images spanning the entire sensory organ. These images were then used to create detailed reconstructions of the sensory nervous system in each worm species, demonstrating that both species had the same number of sensory nerve cells, allowing one-to-one comparisons between them. Further analysis showed that while the overall structure of the neuronal connections remains the same between the two species, the neurons in P. pacificus made more diverse connections than those in C. elegans. Detailed studies of gene activity also revealed that neurons in each species switched on a slightly different group of genes, possibly indicating that each type of worm processes sensory signals in different ways. These results shed new light on how nervous systems in related species can change over time without any change in neuron count. In the future, a better understanding of these changes could link the evolution of the nervous system to the emergence of different behaviors, in both simple and more complex organisms.
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Affiliation(s)
- Ray L Hong
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany.,Department of Biology, California State University, Northridge, Northridge, United States
| | - Metta Riebesell
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Daniel J Bumbarger
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Steven J Cook
- Department of Biological Sciences, Columbia University, New York, United States
| | - Heather R Carstensen
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Tahmineh Sarpolaki
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jessica Castrejon
- Department of Biology, California State University, Northridge, Northridge, United States
| | - Eduardo Moreno
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Bogdan Sieriebriennikov
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max-Planck Institute for Developmental Biology, Tuebingen, Germany
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31
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Woldemariam S, Nagpal J, Hill T, Li J, Schneider MW, Shankar R, Futey M, Varshney A, Ali N, Mitchell J, Andersen K, Barsi-Rhyne B, Tran A, Costa WS, Krzyzanowski MC, Yu YV, Brueggemann C, Hamilton OS, Ferkey DM, VanHoven M, Sengupta P, Gottschalk A, L'Etoile N. Using a Robust and Sensitive GFP-Based cGMP Sensor for Real-Time Imaging in Intact Caenorhabditis elegans. Genetics 2019; 213:59-77. [PMID: 31331946 PMCID: PMC6727795 DOI: 10.1534/genetics.119.302392] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/05/2019] [Indexed: 12/31/2022] Open
Abstract
cGMP plays a role in sensory signaling and plasticity by regulating ion channels, phosphodiesterases, and kinases. Studies that primarily used genetic and biochemical tools suggest that cGMP is spatiotemporally regulated in multiple sensory modalities. FRET- and GFP-based cGMP sensors were developed to visualize cGMP in primary cell culture and Caenorhabditis elegans to corroborate these findings. While a FRET-based sensor has been used in an intact animal to visualize cGMP, the requirement of a multiple emission system limits its ability to be used on its own as well as with other fluorophores. Here, we demonstrate that a C. elegans codon-optimized version of the cpEGFP-based cGMP sensor FlincG3 can be used to visualize rapidly changing cGMP levels in living, behaving C. elegans We coexpressed FlincG3 with the blue-light-activated guanylyl cyclases BeCyclOp and bPGC in body wall muscles, and found that the rate of change in FlincG3 fluorescence correlated with the rate of cGMP production by each cyclase. Furthermore, we show that FlincG3 responds to cultivation temperature, NaCl concentration changes, and sodium dodecyl sulfate in the sensory neurons AFD, ASEL/R, and PHB, respectively. Intriguingly, FlincG3 fluorescence in ASEL and ASER decreased in response to a NaCl concentration upstep and downstep, respectively, which is opposite in sign to the coexpressed calcium sensor jRGECO1a and previously published calcium recordings. These results illustrate that FlincG3 can be used to report rapidly changing cGMP levels in an intact animal, and that the reporter can potentially reveal unexpected spatiotemporal landscapes of cGMP in response to stimuli.
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Affiliation(s)
- Sarah Woldemariam
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, California 94158
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Jatin Nagpal
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Tyler Hill
- Neuroscience Graduate Program, Brandeis University, Waltham, Massachusetts 02453
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Joy Li
- Department of Biological Sciences, San Jose State University, California 95192
| | - Martin W Schneider
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Raakhee Shankar
- Department of Biological Sciences, San Jose State University, California 95192
| | - Mary Futey
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Aruna Varshney
- Department of Biological Sciences, San Jose State University, California 95192
| | - Nebat Ali
- Department of Biological Sciences, San Jose State University, California 95192
| | - Jordan Mitchell
- Department of Biological Sciences, San Jose State University, California 95192
| | - Kristine Andersen
- Department of Biological Sciences, San Jose State University, California 95192
| | | | - Alan Tran
- Department of Biological Sciences, San Jose State University, California 95192
| | - Wagner Steuer Costa
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Michelle C Krzyzanowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Yanxun V Yu
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - O Scott Hamilton
- Center for Neuroscience, University of California, Davis, California 95618
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Miri VanHoven
- Department of Biological Sciences, San Jose State University, California 95192
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Alexander Gottschalk
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Noelle L'Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
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32
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Sinnige T, Ciryam P, Casford S, Dobson CM, de Bono M, Vendruscolo M. Expression of the amyloid-β peptide in a single pair of C. elegans sensory neurons modulates the associated behavioural response. PLoS One 2019; 14:e0217746. [PMID: 31150491 PMCID: PMC6544271 DOI: 10.1371/journal.pone.0217746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/19/2019] [Indexed: 12/21/2022] Open
Abstract
Although the aggregation of the amyloid-β peptide (Aβ) into amyloid fibrils is a well-established hallmark of Alzheimer’s disease, the complex mechanisms linking this process to neurodegeneration are still incompletely understood. The nematode worm C. elegans is a valuable model organism through which to study these mechanisms because of its simple nervous system and its relatively short lifespan. Standard Aβ-based C. elegans models of Alzheimer’s disease are designed to study the toxic effects of the overexpression of Aβ in the muscle or nervous systems. However, the wide variety of effects associated with the tissue-level overexpression of Aβ makes it difficult to single out and study specific cellular mechanisms related to the onset of Alzheimer’s disease. Here, to better understand how to investigate the early events affecting neuronal signalling, we created a C. elegans model expressing Aβ42, the 42-residue form of Aβ, from a single-copy gene insertion in just one pair of glutamatergic sensory neurons, the BAG neurons. In behavioural assays, we found that the Aβ42-expressing animals displayed a subtle modulation of the response to CO2, compared to controls. Ca2+ imaging revealed that the BAG neurons in young Aβ42-expressing nematodes were activated more strongly than in control animals, and that neuronal activation remained intact until old age. Taken together, our results suggest that Aβ42-expression in this very subtle model of AD is sufficient to modulate the behavioural response but not strong enough to generate significant neurotoxicity, suggesting that slightly more aggressive perturbations will enable effectively studies of the links between the modulation of a physiological response and its associated neurotoxicity.
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Affiliation(s)
- Tessa Sinnige
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Prashanth Ciryam
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Samuel Casford
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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33
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Brandt JP, Rossillo M, Du Z, Ichikawa D, Barnes K, Chen A, Noyes M, Bao Z, Ringstad N. Lineage context switches the function of a C. elegans Pax6 homolog in determining a neuronal fate. Development 2019; 146:dev168153. [PMID: 30890567 PMCID: PMC6503985 DOI: 10.1242/dev.168153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 03/11/2019] [Indexed: 01/26/2023]
Abstract
The sensory nervous system of C. elegans comprises cells with varied molecular and functional characteristics, and is, therefore, a powerful model for understanding mechanisms that generate neuronal diversity. We report here that VAB-3, a C. elegans homolog of the homeodomain-containing protein Pax6, has opposing functions in regulating expression of a specific chemosensory fate. A homeodomain-only short isoform of VAB-3 is expressed in BAG chemosensory neurons, where it promotes gene expression and cell function. In other cells, a long isoform of VAB-3, comprising a Paired homology domain and a homeodomain, represses expression of ETS-5, a transcription factor required for expression of BAG fate. Repression of ets-5 requires the Eyes Absent homolog EYA-1 and the Six-class homeodomain protein CEH-32. We determined sequences that mediate high-affinity binding of ETS-5, VAB-3 and CEH-32. The ets-5 locus is enriched for ETS-5-binding sites but lacks sequences that bind VAB-3 and CEH-32, suggesting that these factors do not directly repress ets-5 expression. We propose that a promoter-selection system together with lineage-specific expression of accessory factors allows VAB-3/Pax6 to either promote or repress expression of specific cell fates in a context-dependent manner. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Julia P Brandt
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Mary Rossillo
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Zhuo Du
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - David Ichikawa
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Kristopher Barnes
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Allison Chen
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Marcus Noyes
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Zhirong Bao
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, Helen L. and Martin S. Kimmel Center for Biology and Medicine, and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
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34
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Harris G, Wu T, Linfield G, Choi MK, Liu H, Zhang Y. Molecular and cellular modulators for multisensory integration in C. elegans. PLoS Genet 2019; 15:e1007706. [PMID: 30849079 PMCID: PMC6426271 DOI: 10.1371/journal.pgen.1007706] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/20/2019] [Accepted: 01/23/2019] [Indexed: 12/19/2022] Open
Abstract
In the natural environment, animals often encounter multiple sensory cues that are simultaneously present. The nervous system integrates the relevant sensory information to generate behavioral responses that have adaptive values. However, the neuronal basis and the modulators that regulate integrated behavioral response to multiple sensory cues are not well defined. Here, we address this question using a behavioral decision in C. elegans when the animal is presented with an attractive food source together with a repulsive odorant. We identify specific sensory neurons, interneurons and neuromodulators that orchestrate the decision-making process, suggesting that various states and contexts may modulate the multisensory integration. Among these modulators, we characterize a new function of a conserved TGF-β pathway that regulates the integrated decision by inhibiting the signaling from a set of central neurons. Interestingly, we find that a common set of modulators, including the TGF-β pathway, regulate the integrated response to the pairing of different foods and repellents. Together, our results provide mechanistic insights into the modulatory signals regulating multisensory integration. The present study characterizes the modulation of a behavioral decision in C. elegans when the worm is presented with a food lawn that is paired with a repulsive smell. We show that multiple specific sensory neurons and interneurons play roles in making the decision. We also identify several modulatory molecules that are essential for the integrated decision when the animal faces a choice between the cues of opposing valence. We further show that many of these factors, which often represent different states and contexts, are common for behavioral decisions that integrate sensory information from different types of foods and repellents. Overall, our results reveal the molecular and cellular basis for integration of simultaneously present attractive and repulsive cues to fine-tune decision-making.
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Affiliation(s)
- Gareth Harris
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
- * E-mail: (GH); (YZ)
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Gaia Linfield
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - He Liu
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Sciences, Harvard University, Cambridge, MA, United States of America
- * E-mail: (GH); (YZ)
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35
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Worthy SE, Rojas GL, Taylor CJ, Glater EE. Identification of Odor Blend Used by Caenorhabditis elegans for Pathogen Recognition. Chem Senses 2019; 43:169-180. [PMID: 29373666 PMCID: PMC6018680 DOI: 10.1093/chemse/bjy001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Animals have evolved specialized pathways to detect appropriate food sources and avoid harmful ones. Caenorhabditis elegans can distinguish among the odors of various species of bacteria, its major food source, but little is known about what specific chemical cue or combination of chemical cues C. elegans uses to detect and recognize different microbes. Here, we examine the strong innate attraction of C. elegans for the odor of the pathogenic bacterium, Serratia marcescens. This initial attraction likely facilitates ingestion and infection of the C. elegans host. Using solid-phase microextraction and gas chromatography coupled with mass spectrometry, we identify 5 volatile odors released by S. marcescens and identify those that are attractive to C. elegans. We use genetic methods to show that the amphid chemosensory neuron, AWCON, senses both S. marcescens-released 2-butanone and acetone and drives attraction to S. marcescens. In C. elegans, pairing a single odorant with food deprivation results in a reduced attractive response for that specific odor. We find that pairing the natural odor of S. marcescens with food deprivation results in a reduced attraction for the natural odor of S. marcescens and a similar reduced attraction for the synthetic blend of acetone and 2-butanone. This result indicates that only 2 odorants represent the more complex odor bouquet of S. marcescens. Although bacterial-released volatiles have long been known to be attractive to C. elegans, this study defines for the first time specific volatile cues that represent a particular bacterium to C. elegans.
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Affiliation(s)
| | - German L Rojas
- Department of Neuroscience, Pomona College, Claremont, CA, USA
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36
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Doshi S, Price E, Landis J, Barot U, Sabatella M, Lans H, Kalb RG. Neuropeptide signaling regulates the susceptibility of developing C. elegans to anoxia. Free Radic Biol Med 2019; 131:197-208. [PMID: 30529384 DOI: 10.1016/j.freeradbiomed.2018.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/05/2018] [Accepted: 12/05/2018] [Indexed: 02/04/2023]
Abstract
Inadequate delivery of oxygen to organisms during development can lead to cell dysfunction/death and life-long disabilities. Although the susceptibility of developing cells to low oxygen conditions changes with maturation, the cellular and molecular pathways that govern responses to low oxygen are incompletely understood. Here we show that developing Caenorhabditis elegans are substantially more sensitive to anoxia than adult animals and that this sensitivity is controlled by nervous system generated hormones (e.g., neuropeptides). A screen of neuropeptide genes identified and validated nlp-40 and its receptor aex-2 as a key regulator of anoxic survival in developing worms. The survival-promoting action of impaired neuropeptide signaling does not rely on five known stress resistance pathways and is specific to anoxic insult. Together, these data highlight a novel cell non-autonomous pathway that regulates the susceptibility of developing organisms to anoxia.
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Affiliation(s)
- Shachee Doshi
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Emma Price
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Justin Landis
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Urva Barot
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Mariangela Sabatella
- Department of Molecular Genetics, Erasmus Medical Centre, Oncode Institute, Cancer Genomics Netherlands, Rotterdam 3015 CN, the Netherlands
| | - Hannes Lans
- Department of Molecular Genetics, Erasmus Medical Centre, Oncode Institute, Cancer Genomics Netherlands, Rotterdam 3015 CN, the Netherlands
| | - Robert G Kalb
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Plasticity of the Electrical Connectome of C. elegans. Cell 2019; 176:1174-1189.e16. [PMID: 30686580 PMCID: PMC10064801 DOI: 10.1016/j.cell.2018.12.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/12/2018] [Accepted: 12/14/2018] [Indexed: 11/23/2022]
Abstract
The specific patterns and functional properties of electrical synapses of a nervous system are defined by the neuron-specific complement of electrical synapse constituents. We systematically examined the molecular composition of the electrical connectome of the nematode C. elegans through a genome- and nervous-system-wide analysis of the expression patterns of the invertebrate electrical synapse constituents, the innexins. We observe highly complex combinatorial expression patterns throughout the nervous system and found that these patterns change in a strikingly neuron-type-specific manner throughout the nervous system when animals enter an insulin-controlled diapause arrest stage under harsh environmental conditions, the dauer stage. By analyzing several individual synapses, we demonstrate that dauer-specific electrical synapse remodeling is responsible for specific aspects of the altered locomotory and chemosensory behavior of dauers. We describe an intersectional gene regulatory mechanism involving terminal selector and FoxO transcription factors mediating dynamic innexin expression plasticity in a neuron-type- and environment-specific manner.
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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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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: 21] [Impact Index Per Article: 3.5] [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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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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Hao Y, Yang W, Ren J, Hall Q, Zhang Y, Kaplan JM. Thioredoxin shapes the C. elegans sensory response to Pseudomonas produced nitric oxide. eLife 2018; 7:36833. [PMID: 30014846 PMCID: PMC6066330 DOI: 10.7554/elife.36833] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/01/2018] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) is released into the air by NO-producing organisms; however, it is unclear if animals utilize NO as a sensory cue. We show that C. elegans avoids Pseudomonas aeruginosa (PA14) in part by detecting PA14-produced NO. PA14 mutants deficient for NO production fail to elicit avoidance and NO donors repel worms. PA14 and NO avoidance are mediated by a chemosensory neuron (ASJ) and these responses require receptor guanylate cyclases and cyclic nucleotide gated ion channels. ASJ exhibits calcium increases at both the onset and removal of NO. These NO-evoked ON and OFF calcium transients are affected by a redox sensing protein, TRX-1/thioredoxin. TRX-1’s trans-nitrosylation activity inhibits the ON transient whereas TRX-1’s de-nitrosylation activity promotes the OFF transient. Thus, C. elegans exploits bacterially produced NO as a cue to mediate avoidance and TRX-1 endows ASJ with a bi-phasic response to NO exposure. Nitric oxide is a colorless gas that contains one nitrogen atom and one oxygen atom. Found at very low levels in the air, this gas is produced by the intense heat of lightning strikes and by combustion engines. Almost all living organisms also produce nitric oxide. In animals, for example, nitric oxide regulates blood pressure and signaling between neurons. However, it was not known if animals could detect nitric oxide in their environment and respond to it. Caenorhabditis elegans is a worm that has been intensively studied in many fields of biology. Unlike most animals, it cannot make nitric oxide. Yet, living in the soil, C. elegans does come into contact with many microbes that can, including the bacterium Pseudomonas aeruginosa. These bacteria can infect and kill C. elegans, and so the worm typically avoids them. Hao, Yang et al. asked whether C. elegans does so by detecting the nitric oxide that these harmful bacteria release into their environment. First, worms were added to a petri dish where a small patch of P. aeruginosa was growing. Consistent with previous results, the worms had all moved away from the bacteria after a few hours. The experiments were then repeated with mutant bacteria that cannot produce nitric oxide. The worms were less likely to avoid these mutant bacteria, suggesting that C. elegans does indeed avoid infection by detecting bacterially produced nitric oxide. Next, using a range of techniques, Hao, Yang et al. showed that C. elegans avoids nitric oxide released into its environment by detecting the gas via a pair of sensory neurons. These neurons require several specific proteins to be able to detect nitric oxide and respond to it. In particular, a protein called Thioredoxin was found to determine the beginning and end of the worm’s sensory response to nitric oxide. All of these proteins are also found in many other animals, and so it is possible that these findings may be relevant to other species too. Further studies are now needed to confirm whether other organisms can sense nitric oxide from their environment and, if so, how their nervous systems equip them to do this.
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Affiliation(s)
- Yingsong Hao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Jing Ren
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Qi Hall
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, United States
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
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Abstract
The recently determined connectome of the Caenorhabditis elegans adult male, together with the known connectome of the hermaphrodite, opens up the possibility for a comprehensive description of sexual dimorphism in this species and the identification and study of the neural circuits underlying sexual behaviors. The C. elegans nervous system consists of 294 neurons shared by both sexes plus neurons unique to each sex, 8 in the hermaphrodite and 91 in the male. The sex-specific neurons are well integrated within the remainder of the nervous system; in the male, 16% of the input to the shared component comes from male-specific neurons. Although sex-specific neurons are involved primarily, but not exclusively, in controlling sex-unique behavior—egg-laying in the hermaphrodite and copulation in the male—these neurons act together with shared neurons to make navigational choices that optimize reproductive success. Sex differences in general behaviors are underlain by considerable dimorphism within the shared component of the nervous system itself, including dimorphism in synaptic connectivity.
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Affiliation(s)
- Scott W. Emmons
- Department of Genetics and Dominick Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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43
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Ravi B, Nassar LM, Kopchock RJ, Dhakal P, Scheetz M, Collins KM. Ratiometric Calcium Imaging of Individual Neurons in Behaving Caenorhabditis Elegans. J Vis Exp 2018. [PMID: 29443112 PMCID: PMC5912386 DOI: 10.3791/56911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
It has become increasingly clear that neural circuit activity in behaving animals differs substantially from that seen in anesthetized or immobilized animals. Highly sensitive, genetically encoded fluorescent reporters of Ca2+ have revolutionized the recording of cell and synaptic activity using non-invasive optical approaches in behaving animals. When combined with genetic and optogenetic techniques, the molecular mechanisms that modulate cell and circuit activity during different behavior states can be identified. Here we describe methods for ratiometric Ca2+ imaging of single neurons in freely behaving Caenorhabditis elegans worms. We demonstrate a simple mounting technique that gently overlays worms growing on a standard Nematode Growth Media (NGM) agar block with a glass coverslip, permitting animals to be recorded at high-resolution during unrestricted movement and behavior. With this technique, we use the sensitive Ca2+ reporter GCaMP5 to record changes in intracellular Ca2+ in the serotonergic Hermaphrodite Specific Neurons (HSNs) as they drive egg-laying behavior. By co-expressing mCherry, a Ca2+-insensitive fluorescent protein, we can track the position of the HSN within ~ 1 µm and correct for fluctuations in fluorescence caused by changes in focus or movement. Simultaneous, infrared brightfield imaging allows for behavior recording and animal tracking using a motorized stage. By integrating these microscopic techniques and data streams, we can record Ca2+ activity in the C. elegans egg-laying circuit as it progresses between inactive and active behavior states over tens of minutes.
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Affiliation(s)
- Bhavya Ravi
- Neuroscience Program, University of Miami School of Medicine
| | - Layla M Nassar
- Neuroscience Program, University of Miami School of Medicine; Department of Biology, University of Miami
| | | | | | | | - Kevin M Collins
- Neuroscience Program, University of Miami School of Medicine; Department of Biology, University of Miami;
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44
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Antagonistic regulation of trafficking to Caenorhabditis elegans sensory cilia by a Retinal Degeneration 3 homolog and retromer. Proc Natl Acad Sci U S A 2017; 115:E438-E447. [PMID: 29282322 DOI: 10.1073/pnas.1712302115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sensory neurons often possess cilia with elaborate membrane structures that are adapted to the sensory modality of the host cell. Mechanisms that target sensory transduction proteins to these specialized membrane domains remain poorly understood. Here, we show that a homolog of the human retinal dystrophy gene Retinal Degeneration 3 (RD3) is a Golgi-associated protein required for efficient trafficking of a sensory receptor, the receptor-type guanylate cyclase GCY-9, to cilia in chemosensory neurons of the nematode Caenorhabditis elegans The trafficking defect caused by mutation of the nematode RD3 homolog is suppressed in vivo by mutation of key components of the retromer complex, which mediates recycling of cargo from endosomes to the Golgi. Our data show that there exists a critical balance in sensory neurons between the rates of anterograde and retrograde trafficking of cargo destined for the sensory cilium and this balance requires molecular specialization at an early stage of the secretory pathway.
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45
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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: 35] [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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Stroehlein AJ, Young ND, Korhonen PK, Chang BCH, Nejsum P, Pozio E, La Rosa G, Sternberg PW, Gasser RB. Whipworm kinomes reflect a unique biology and adaptation to the host animal. Int J Parasitol 2017; 47:857-866. [PMID: 28606697 DOI: 10.1016/j.ijpara.2017.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/14/2017] [Accepted: 04/20/2017] [Indexed: 01/19/2023]
Abstract
Roundworms belong to a diverse phylum (Nematoda) which is comprised of many parasitic species including whipworms (genus Trichuris). These worms have adapted to a biological niche within the host and exhibit unique morphological characteristics compared with other nematodes. Although these adaptations are known, the underlying molecular mechanisms remain elusive. The availability of genomes and transcriptomes of some whipworms now enables detailed studies of their molecular biology. Here, we defined and curated the full complement of an important class of enzymes, the protein kinases (kinomes) of two species of Trichuris, using an advanced and integrated bioinformatic pipeline. We investigated the transcription of Trichuris suis kinase genes across developmental stages, sexes and tissues, and reveal that selectively transcribed genes can be linked to central roles in developmental and reproductive processes. We also classified and functionally annotated the curated kinomes by integrating evidence from structural modelling and pathway analyses, and compared them with other curated kinomes of phylogenetically diverse nematode species. Our findings suggest unique adaptations in signalling processes governing worm morphology and biology, and provide an important resource that should facilitate experimental investigations of kinases and the biology of signalling pathways in nematodes.
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Affiliation(s)
- Andreas J Stroehlein
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Pasi K Korhonen
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Bill C H Chang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia; Yourgene Bioscience, New Taipei City, Taiwan
| | - Peter Nejsum
- Department of Clinical Medicine, Department of Infectious Diseases, Aarhus University, Aarhus, Denmark
| | | | | | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
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47
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Ghosh DD, Nitabach MN, Zhang Y, Harris G. Multisensory integration in C. elegans. Curr Opin Neurobiol 2017; 43:110-118. [PMID: 28273525 PMCID: PMC5501174 DOI: 10.1016/j.conb.2017.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/26/2017] [Accepted: 01/30/2017] [Indexed: 12/19/2022]
Abstract
Multisensory integration is a neural process by which signals from two or more distinct sensory channels are simultaneously processed to form a more coherent representation of the environment. Multisensory integration, especially when combined with a survey of internal states, provides selective advantages for animals navigating complex environments. Despite appreciation of the importance of multisensory integration in behavior, the underlying molecular and cellular mechanisms remain poorly understood. Recent work looking at how Caenorhabditis elegans makes multisensory decisions has yielded mechanistic insights into how a relatively simple and well-defined nervous system employs circuit motifs of defined features, synaptic signals and extrasynaptic neurotransmission, as well as neuromodulators in processing and integrating multiple sensory inputs to generate flexible and adaptive behavioral outputs.
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Affiliation(s)
- D Dipon Ghosh
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States; Department of Genetics, Yale University, New Haven, CT, United States; Kavli Institute for Neuroscience, Yale University, New Haven, CT, United States.
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, United States.
| | - Gareth Harris
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, United States
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48
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Cevallos JA, Okubo RP, Perlman SJ, Hallem EA. Olfactory Preferences of the Parasitic Nematode Howardula aoronymphium and its Insect Host Drosophila falleni. J Chem Ecol 2017; 43:362-373. [PMID: 28315996 DOI: 10.1007/s10886-017-0834-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/09/2017] [Accepted: 03/06/2017] [Indexed: 10/19/2022]
Abstract
Many parasitic nematodes have an environmental infective stage that searches for hosts. Olfaction plays an important role in this process, with nematodes navigating their environment using host-emitted and environmental olfactory cues. The interactions between parasitic nematodes and their hosts are also influenced by the olfactory behaviors of the host, since host olfactory preferences drive behaviors that may facilitate or impede parasitic infection. However, how olfaction shapes parasite-host interactions is poorly understood. Here we investigated this question using the insect-parasitic nematode Howardula aoronymphium and its host, the mushroom fly Drosophila falleni. We found that both H. aoronymphium and D. falleni are attracted to mushroom odor and a subset of mushroom-derived odorants, but they have divergent olfactory preferences that are tuned to different mushroom odorants despite their shared mushroom environment. H. aoronymphium and D. falleni respond more narrowly to odorants than Caenorhabditis elegans and Drosophila melanogaster, consistent with their more specialized niches. Infection of D. falleni with H. aoronymphium alters its olfactory preferences, rendering it more narrowly tuned to mushroom odor. Our results establish H. aoronymphium-D. falleni as a model system for studying olfaction in the context of parasite-host interactions.
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Affiliation(s)
- James A Cevallos
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Ryo P Okubo
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Steve J Perlman
- Department of Biology, University of Victoria, Victoria, British Columbia, V8W 3N5, Canada
| | - Elissa A Hallem
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA.
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de Wolf E, Cook J, Dale N. Evolutionary adaptation of the sensitivity of connexin26 hemichannels to CO2. Proc Biol Sci 2017; 284:20162723. [PMID: 28148750 PMCID: PMC5310615 DOI: 10.1098/rspb.2016.2723] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/06/2017] [Indexed: 11/12/2022] Open
Abstract
CO2 readily combines with H2O to form [Formula: see text] and H+ Because an increase of only 100 nM in the concentration of H+ (a decrease of 0.1 unit of pH) in blood can prove fatal, the regulated excretion of CO2 during breathing is an essential life-preserving process. In rodents and humans, this vital process is mediated in part via the direct sensing of CO2 via connexin26 (Cx26). CO2 binds to hemichannels of Cx26 causing them to open and allow release of the neurotransmitter ATP. If Cx26 were to be a universal and important CO2 sensor across all homeothermic animals, then a simple hypothesis would posit that it should exhibit evolutionary adaptation in animals with different homeostatic set points for the regulation of partial pressure of arterial CO2 (PaCO2). In humans and rats, PaCO2 is regulated around a set point of 40 mmHg. By contrast, birds are able to maintain cerebral blood flow and breathing at much lower levels of PaCO2 Fossorial mammals, such as the mole rat, live exclusively underground in burrows that are both hypoxic and hypercapnic and can thrive under very hypercapnic conditions. We have therefore compared the CO2 sensitivity of Cx26 from human, chicken, rat and mole rat (Heterocephalus glaber). We find that both the affinity and cooperativity of CO2 binding to Cx26 have been subjected to evolutionary adaption in a manner consistent with the homeostatic requirements of these four species. This is analogous to the evolutionary adaptation of haemoglobin to the needs of O2 transport across the animal kingdom and supports the hypothesis that Cx26 is an important and universal CO2 sensor in homeotherms.
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Affiliation(s)
- Elizabeth de Wolf
- School of Life Sciences, University of Warwick, Gibbet Hill Rd, Coventry CV4 7AL, UK
| | - Jonathan Cook
- School of Life Sciences, University of Warwick, Gibbet Hill Rd, Coventry CV4 7AL, UK
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Gibbet Hill Rd, Coventry CV4 7AL, UK
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Control of Neuropeptide Expression by Parallel Activity-dependent Pathways in Caenorhabditis elegans. Sci Rep 2017; 7:38734. [PMID: 28139692 PMCID: PMC5282578 DOI: 10.1038/srep38734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/14/2016] [Indexed: 12/19/2022] Open
Abstract
Monitoring of neuronal activity within circuits facilitates integrated responses and rapid changes in behavior. We have identified a system in Caenorhabditis elegans where neuropeptide expression is dependent on the ability of the BAG neurons to sense carbon dioxide. In C. elegans, CO2 sensing is predominantly coordinated by the BAG-expressed receptor-type guanylate cyclase GCY-9. GCY-9 binding to CO2 causes accumulation of cyclic GMP and opening of the cGMP-gated TAX-2/TAX-4 cation channels; provoking an integrated downstream cascade that enables C. elegans to avoid high CO2. Here we show that cGMP regulation by GCY-9 and the PDE-1 phosphodiesterase controls BAG expression of a FMRFamide-related neuropeptide FLP-19 reporter (flp-19::GFP). This regulation is specific for CO2-sensing function of the BAG neurons, as loss of oxygen sensing function does not affect flp-19::GFP expression. We also found that expression of flp-19::GFP is controlled in parallel to GCY-9 by the activity-dependent transcription factor CREB (CRH-1) and the cAMP-dependent protein kinase (KIN-2) signaling pathway. We therefore show that two parallel pathways regulate neuropeptide gene expression in the BAG sensory neurons: the ability to sense changes in carbon dioxide and CREB transcription factor. Such regulation may be required in particular environmental conditions to enable sophisticated behavioral decisions to be performed.
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