1
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Nair T, Weathers BA, Stuhr NL, Nhan JD, Curran SP. Serotonin deficiency from constitutive SKN-1 activation drives pathogen apathy. Nat Commun 2024; 15:8129. [PMID: 39285192 PMCID: PMC11405893 DOI: 10.1038/s41467-024-52233-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 08/29/2024] [Indexed: 09/20/2024] Open
Abstract
When an organism encounters a pathogen, the host innate immune system activates to defend against pathogen colonization and toxic xenobiotics produced. C. elegans employ multiple defense systems to ensure survival when exposed to Pseudomonas aeruginosa including activation of the cytoprotective transcription factor SKN-1/NRF2. Although wildtype C. elegans quickly learn to avoid pathogens, here we describe a peculiar apathy-like behavior towards PA14 in animals with constitutive activation of SKN-1, whereby animals choose not to leave and continue to feed on the pathogen even when a non-pathogenic and healthspan-promoting food option is available. Although lacking the urgency to escape the infectious environment, animals with constitutive SKN-1 activity are not oblivious to the presence of the pathogen and display the typical pathogen-induced intestinal distension and eventual demise. SKN-1 activation, specifically in neurons and intestinal tissues, orchestrates a unique transcriptional program which leads to defects in serotonin signaling that is required from both neurons and non-neuronal tissues. Serotonin depletion from SKN-1 activation limits pathogen defenses capacity, drives the pathogen-associated apathy behaviors and induces a synthetic sensitivity to selective serotonin reuptake inhibitors. Taken together, our work reveals interesting insights into how animals perceive environmental pathogens and subsequently alter behavior and cellular programs to promote survival.
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Affiliation(s)
- Tripti Nair
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Brandy A Weathers
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Nicole L Stuhr
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - James D Nhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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2
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Marogi JG, Murphy CT, Myhrvold C, Gitai Z. Pseudomonas aeruginosa modulates both Caenorhabditis elegans attraction and pathogenesis by regulating nitrogen assimilation. Nat Commun 2024; 15:7927. [PMID: 39256376 PMCID: PMC11387622 DOI: 10.1038/s41467-024-52227-3] [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: 06/25/2024] [Accepted: 08/29/2024] [Indexed: 09/12/2024] Open
Abstract
Detecting chemical signals is important for identifying food sources and avoiding harmful agents. Like many animals, C. elegans use olfaction to chemotax towards their main food source, bacteria. However, little is known about the bacterial compounds governing C. elegans attraction to bacteria and the physiological importance of these compounds to bacteria. Here, we address these questions by investigating the function of a small RNA, P11, in the pathogen, Pseudomonas aeruginosa, that was previously shown to mediate learned pathogen avoidance. We discovered that this RNA also affects the attraction of untrained C. elegans to P. aeruginosa and does so by controlling production of ammonia, a volatile odorant produced during nitrogen assimilation. We describe the complex regulation of P. aeruginosa nitrogen assimilation, which is mediated by a partner-switching mechanism involving environmental nitrates, sensor proteins, and P11. In addition to mediating C. elegans attraction, we demonstrate that nitrogen assimilation mutants perturb bacterial fitness and pathogenesis during C. elegans infection by P. aeruginosa. These studies define ammonia as a major mediator of trans-kingdom signaling, implicate nitrogen assimilation as important for both bacteria and host organisms, and highlight how a bacterial metabolic pathway can either benefit or harm a host in different contexts.
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Affiliation(s)
- Jacob G Marogi
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Coleen T Murphy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Lewis Sigler Institute, Princeton University, Princeton, NJ, USA
| | - Cameron Myhrvold
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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3
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Liu P, Liu X, Qi B. UPR ER-immunity axis acts as physiological food evaluation system that promotes aversion behavior in sensing low-quality food. eLife 2024; 13:RP94181. [PMID: 39235964 PMCID: PMC11377039 DOI: 10.7554/elife.94181] [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] [Indexed: 09/07/2024] Open
Abstract
To survive in challenging environments, animals must develop a system to assess food quality and adjust their feeding behavior accordingly. However, the mechanisms that regulate this chronic physiological food evaluation system, which monitors specific nutrients from ingested food and influences food-response behavior, are still not fully understood. Here, we established a low-quality food evaluation assay system and found that heat-killed E. coli (HK-E. coli), a low-sugar food, triggers cellular UPRER and immune response. This encourages animals to avoid low-quality food. The physiological system for evaluating low-quality food depends on the UPRER (IRE-1/XBP-1) - Innate immunity (PMK-1/p38 MAPK) axis, particularly its neuronal function, which subsequently regulates feeding behaviors. Moreover, animals can adapt to a low-quality food environment through sugar supplementation, which inhibits the UPRER -PMK-1 regulated stress response by increasing vitamin C biosynthesis. This study reveals the role of the cellular stress response pathway as physiological food evaluation system for assessing nutritional deficiencies in food, thereby enhancing survival in natural environments.
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Affiliation(s)
- Pengfei Liu
- Southwest United Graduate School,Yunnan Key Laboratory of Cell Metabolism and Diseases, State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Xinyi Liu
- Southwest United Graduate School,Yunnan Key Laboratory of Cell Metabolism and Diseases, State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Bin Qi
- Southwest United Graduate School,Yunnan Key Laboratory of Cell Metabolism and Diseases, State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
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4
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Zhang Y, Iino Y, Schafer WR. Behavioral plasticity. Genetics 2024; 228:iyae105. [PMID: 39158469 DOI: 10.1093/genetics/iyae105] [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: 02/01/2024] [Accepted: 06/10/2024] [Indexed: 08/20/2024] Open
Abstract
Behavioral plasticity allows animals to modulate their behavior based on experience and environmental conditions. Caenorhabditis elegans exhibits experience-dependent changes in its behavioral responses to various modalities of sensory cues, including odorants, salts, temperature, and mechanical stimulations. Most of these forms of behavioral plasticity, such as adaptation, habituation, associative learning, and imprinting, are shared with other animals. The C. elegans nervous system is considerably tractable for experimental studies-its function can be characterized and manipulated with molecular genetic methods, its activity can be visualized and analyzed with imaging approaches, and the connectivity of its relatively small number of neurons are well described. Therefore, C. elegans provides an opportunity to study molecular, neuronal, and circuit mechanisms underlying behavioral plasticity that are either conserved in other animals or unique to this species. These findings reveal insights into how the nervous system interacts with the environmental cues to generate behavioral changes with adaptive values.
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Affiliation(s)
- Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Yuichi Iino
- Department of Biological Sciences, University of Tokyo, Tokyo 113-0032, Japan
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, Cambridgeshire CB2 0QH, UK
- Department of Biology, KU Leuven, 3000 Leuven, Belgium
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5
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Kramer TS, Wan FK, Pugliese SM, Atanas AA, Hiser AW, Luo J, Bueno E, Flavell SW. Neural Sequences Underlying Directed Turning in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.11.607076. [PMID: 39149398 PMCID: PMC11326294 DOI: 10.1101/2024.08.11.607076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Complex behaviors like navigation rely on sequenced motor outputs that combine to generate effective movement. The brain-wide organization of the circuits that integrate sensory signals to select and execute appropriate motor sequences is not well understood. Here, we characterize the architecture of neural circuits that control C. elegans olfactory navigation. We identify error-correcting turns during navigation and use whole-brain calcium imaging and cell-specific perturbations to determine their neural underpinnings. These turns occur as motor sequences accompanied by neural sequences, in which defined neurons activate in a stereotyped order during each turn. Distinct neurons in this sequence respond to sensory cues, anticipate upcoming turn directions, and drive movement, linking key features of this sensorimotor behavior across time. The neuromodulator tyramine coordinates these sequential brain dynamics. Our results illustrate how neuromodulation can act on a defined neural architecture to generate sequential patterns of activity that link sensory cues to motor actions.
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Affiliation(s)
- Talya S. Kramer
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- MIT Biology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Flossie K. Wan
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sarah M. Pugliese
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Adam A. Atanas
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alex W. Hiser
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jinyue Luo
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Eric Bueno
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Steven W. Flavell
- Picower Institute for Learning & Memory, Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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6
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Hajdú G, Szathmári C, Sőti C. Modeling Host-Pathogen Interactions in C. elegans: Lessons Learned from Pseudomonas aeruginosa Infection. Int J Mol Sci 2024; 25:7034. [PMID: 39000143 PMCID: PMC11241598 DOI: 10.3390/ijms25137034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 06/17/2024] [Accepted: 06/22/2024] [Indexed: 07/16/2024] Open
Abstract
Infections, such as that by the multiresistant opportunistic bacterial pathogen Pseudomonas aeruginosa, may pose a serious health risk, especially on vulnerable patient populations. The nematode Caenorhabditis elegans provides a simple organismal model to investigate both pathogenic mechanisms and the emerging role of innate immunity in host protection. Here, we review the virulence and infection strategies of P. aeruginosa and host defenses of C. elegans. We summarize the recognition mechanisms of patterns of pathogenesis, including novel pathogen-associated molecular patterns and surveillance immunity of translation, mitochondria, and lysosome-related organelles. We also review the regulation of antimicrobial and behavioral defenses by the worm's neuroendocrine system. We focus on how discoveries in this rich field align with well-characterized evolutionary conserved protective pathways, as well as on potential crossovers to human pathogenesis and innate immune responses.
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Affiliation(s)
- Gábor Hajdú
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csenge Szathmári
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
| | - Csaba Sőti
- Department of Molecular Biology, Semmelweis University, 1094 Budapest, Hungary
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7
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Lei M, Tan Y, Tu H, Tan W. Neuronal basis and diverse mechanisms of pathogen avoidance in Caenorhabditis elegans. Front Immunol 2024; 15:1353747. [PMID: 38751431 PMCID: PMC11094273 DOI: 10.3389/fimmu.2024.1353747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/22/2024] [Indexed: 05/18/2024] Open
Abstract
Pathogen avoidance behaviour has been observed across animal taxa as a vital host-microbe interaction mechanism. The nematode Caenorhabditis elegans has evolved multiple diverse mechanisms for pathogen avoidance under natural selection pressure. We summarise the current knowledge of the stimuli that trigger pathogen avoidance, including alterations in aerotaxis, intestinal bloating, and metabolites. We then survey the neural circuits involved in pathogen avoidance, transgenerational epigenetic inheritance of pathogen avoidance, signalling crosstalk between pathogen avoidance and innate immunity, and C. elegans avoidance of non-Pseudomonas bacteria. In this review, we highlight the latest advances in understanding host-microbe interactions and the gut-brain axis.
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Affiliation(s)
- Ming Lei
- Academy of Medical Engineering and Translational Medicine (AMT), Tianjin University, Tianjin, China
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Yanheng Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Weihong Tan
- Academy of Medical Engineering and Translational Medicine (AMT), Tianjin University, Tianjin, China
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
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8
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Lee SA, Cho Y, Schafer WR, Lu H. Dynamic temperature control in microfluidics for in vivo imaging of cold-sensing in C. elegans. Biophys J 2024; 123:947-956. [PMID: 38449311 PMCID: PMC11052694 DOI: 10.1016/j.bpj.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/26/2024] [Accepted: 03/04/2024] [Indexed: 03/08/2024] Open
Abstract
The ability to perceive temperature is crucial for most animals. It enables them to maintain their body temperature and swiftly react to noxiously cold or hot objects. Caenorhabditis elegans is a powerful genetic model for the study of thermosensation as its simple nervous system is well characterized and its transparent body is suited for in vivo functional imaging of neurons. The behavior triggered by experience-dependent thermosensation has been well studied in C. elegans under temperature-gradient environments. However, how C. elegans senses temperature via its nervous system is not well understood due to the limitations of currently available technologies. One major bottleneck is the difficulty in creating fast temperature changes, especially cold stimuli. Here, we developed a microfluidic-based platform that allowed the in vivo functional imaging of C. elegans responding to well-controlled temporally varying temperature stimulation by rapidly switching fluid streams at different temperatures. We used computational models to enable rational design and optimization of experimental conditions. We validated the design and utility of our system with studies of the functional role of thermosensory neurons. We showed that the responses of PVD polymodal nociceptor neurons observed in previous studies can be recapitulated. Further, we highlighted how this platform may be used to dissect neuronal circuits with an example of activity recording in PVC interneurons. Both of these neuron types show sensitization phenotypes. We envision that both the engineered system and the findings in this work will spur further studies of molecular and cellular mechanisms underlying cold-sensing through the nervous system.
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Affiliation(s)
- Sol Ah Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia
| | - Yongmin Cho
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia
| | - William R Schafer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia.
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9
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Nair T, Weathers BA, Stuhr NL, Nhan JD, Curran SP. Serotonin deficiency from constitutive SKN-1 activation drives pathogen apathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.10.579755. [PMID: 38405962 PMCID: PMC10888766 DOI: 10.1101/2024.02.10.579755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
When an organism encounters a pathogen, the host innate immune system activates to defend against pathogen colonization and toxic xenobiotics produced. C. elegans employ multiple defense systems to ensure survival when exposed to Pseudomonas aeruginosa including activation of the cytoprotective transcription factor SKN-1/NRF2. Although wildtype C. elegans quickly learn to avoid pathogens, here we describe a peculiar apathy-like behavior towards PA14 in animals with constitutive activation of SKN-1, whereby animals choose not to leave and continue to feed on the pathogen even when a non-pathogenic and healthspan-promoting food option is available. Although lacking the urgency to escape the infectious environment, animals with constitutive SKN-1 activity are not oblivious to the presence of the pathogen and display the typical pathogen-induced intestinal distension and eventual demise. SKN-1 activation, specifically in neurons and intestinal tissues, orchestrates a unique transcriptional program which leads to defects in serotonin signaling that is required from both neurons and non-neuronal tissues. Serotonin depletion from SKN-1 activation limits pathogen defense capacity, drives the pathogen-associated apathy behaviors and induces a synthetic sensitivity to selective serotonin reuptake inhibitors. Taken together, our work reveals new insights into how animals perceive environmental pathogens and subsequently alter behavior and cellular programs to promote survival. KEY POINTS Identify an apathy-like behavioral response for pathogens resulting from the constitutive activation of the cytoprotective transcription factor SKN-1.Uncover the obligate role for serotonin synthesis in both neuronal and non-neuronal cells for the apathy-like state and ability of serotonin treatment to restore normal behaviors.Characterize the timing and tissue specificity of SKN-1 nuclear localization in neurons and intestinal cells in response to pathogen exposure.Define the unique and context-specific transcriptional signatures of animals with constitutive SKN-1 activation when exposed to pathogenic environments.Reveal necessity for both neuronal and non-neuronal serotonin signaling in host survival from pathogen infection.
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10
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Marogi JG, Murphy CT, Myhrvold C, Gitai Z. P. aeruginosa controls both C. elegans attraction and pathogenesis by regulating nitrogen assimilation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569279. [PMID: 38077073 PMCID: PMC10705433 DOI: 10.1101/2023.11.29.569279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2024]
Abstract
Detecting chemical signals is important for identifying food sources and avoiding harmful agents. Like most animals, C. elegans use olfaction to chemotax towards their main food source, bacteria. However, little is known about the bacterial compounds governing C. elegans attraction to bacteria and the physiological importance of these compounds to bacteria. Here, we address these questions by investigating the function of a small RNA, P11, in the pathogen, Pseudomonas aeruginosa, that was previously shown to mediate learned pathogen avoidance. We discovered that this RNA also affects the attraction of untrained C. elegans to P. aeruginosa and does so by controlling production of ammonia, a volatile odorant produced during nitrogen assimilation. We untangle the complex regulation of P. aeruginosa nitrogen assimilation, which is mediated by a partner-switching mechanism involving environmental nitrates, sensor proteins, and P11. In addition to mediating C. elegans attraction, nitrogen assimilation is important for bacterial fitness and pathogenesis during C. elegans infection by P. aeruginosa . These studies define ammonia as a major mediator of trans-kingdom signaling, reveal the physiological importance of nitrogen assimilation for both bacteria and host organisms, and highlight how a bacterial metabolic pathway can either benefit or harm a host in different contexts.
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11
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Ding J, Peng L, Moon S, Lee HJ, Patel DS, Lu H. An expanded GCaMP reporter toolkit for functional imaging in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2023; 13:jkad183. [PMID: 37565483 PMCID: PMC10542313 DOI: 10.1093/g3journal/jkad183] [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: 06/10/2023] [Accepted: 07/16/2023] [Indexed: 08/12/2023]
Abstract
In living organisms, changes in calcium flux are integral to many different cellular functions and are especially critical for the activity of neurons and myocytes. Genetically encoded calcium indicators (GECIs) have been popular tools for reporting changes in calcium levels in vivo. In particular, GCaMPs, derived from GFP, are the most widely used GECIs and have become an invaluable toolkit for neurophysiological studies. Recently, new variants of GCaMP, which offer a greater variety of temporal dynamics and improved brightness, have been developed. However, these variants are not readily available to the Caenorhabditis elegans research community. This work reports a set of GCaMP6 and jGCaMP7 reporters optimized for C. elegans studies. Our toolkit provides reporters with improved dynamic range, varied kinetics, and targeted subcellular localizations. Besides optimized routine uses, this set of reporters is also well suited for studies requiring fast imaging speeds and low magnification or low-cost platforms.
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Affiliation(s)
- Jimmy Ding
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Lucinda Peng
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sihoon Moon
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyun Jee Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Dhaval S Patel
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hang Lu
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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12
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Mangalath A, Thekkuveettil A. Olfactory imprinting enhances associative learning and memory in C. elegans. Biochem Biophys Res Commun 2023; 674:109-116. [PMID: 37419031 DOI: 10.1016/j.bbrc.2023.07.002] [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: 05/31/2023] [Accepted: 07/01/2023] [Indexed: 07/09/2023]
Abstract
Learning and memory are fundamental processes for an organism's normal physiological function. Learning can occur at any stage of the organism's physiological development. Imprinted memories formed during the early developmental stage, unlike learning and memory, can last a lifetime. It is not clear whether these two types of memories are interlinked. In this study, we investigated whether imprinted memory influences adult learning and memory in a C. elegans model system. We trained the worms for short-term (STAM) and long-term associated memory (LTAM) towards butanone (BT) after conditioning them for imprinted memory towards isoamyl alcohol (IAA). We observed that these worms had improved learning abilities. However, functional imaging revealed that the worms had a long-term depression in the firing pattern in the AIY interneuron, indicating that there were significant changes in neuronal excitation pattern after imprinting, which could explain the enhanced behavioural alterations in animals after imprinting.
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Affiliation(s)
- Aswathy Mangalath
- Division of Molecular Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695012, India
| | - Anoopkumar Thekkuveettil
- Division of Molecular Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695012, India.
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13
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Zhan X, Chen C, Niu L, Du X, Lei Y, Dan R, Wang ZW, Liu P. Locomotion modulates olfactory learning through proprioception in C. elegans. Nat Commun 2023; 14:4534. [PMID: 37500635 PMCID: PMC10374624 DOI: 10.1038/s41467-023-40286-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 07/19/2023] [Indexed: 07/29/2023] Open
Abstract
Locomotor activities can enhance learning, but the underlying circuit and synaptic mechanisms are largely unknown. Here we show that locomotion facilitates aversive olfactory learning in C. elegans by activating mechanoreceptors in motor neurons, and transmitting the proprioceptive information thus generated to locomotion interneurons through antidromic-rectifying gap junctions. The proprioceptive information serves to regulate experience-dependent activities and functional coupling of interneurons that process olfactory sensory information to produce the learning behavior. Genetic destruction of either the mechanoreceptors in motor neurons, the rectifying gap junctions between the motor neurons and locomotion interneurons, or specific inhibitory synapses among the interneurons impairs the aversive olfactory learning. We have thus uncovered an unexpected role of proprioception in a specific learning behavior as well as the circuit, synaptic, and gene bases for this function.
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Affiliation(s)
- Xu Zhan
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Chao Chen
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, Hubei, China
- Department of Orthopaedics, Hefeng Central Hospital, 445800, Enshi, Hubei, China
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Xinran Du
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Ying Lei
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Rui Dan
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
| | - Ping Liu
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.
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14
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Wu CH, Hsu WL, Tsai CC, Chao HR, Wu CY, Chen YH, Lai YR, Chen CH, Tsai MH. 7,10,13,16-Docosatetraenoic acid impairs neurobehavioral development by increasing reactive oxidative species production in Caenorhabditis elegans. Life Sci 2023; 319:121500. [PMID: 36796717 DOI: 10.1016/j.lfs.2023.121500] [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: 06/08/2022] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023]
Abstract
AIMS To investigate human breast milk (HBM) lipids that may adversely affect infant neurodevelopment. MAIN METHODS We performed multivariate analyses that combined lipidomics and psychologic Bayley-III scales to identify which HBM lipids are involved in regulating infant neurodevelopment. We observed a significant moderate negative correlation between 7,10,13,16-docosatetraenoic acid (omega-6, C22H36O2, the common name adrenic acid, AdA) and adaptive behavioral development. We further studied the effects of AdA on neurodevelopment by using Caenorhabditis elegans (C. elegans) as a model. Worms from larval stages L1 to L4 were supplemented with AdA at 5 nominal concentrations (0 μM [control], 0.1 μM, 1 μM, 10 μM, and 100 μM) and subjected to behavioral and mechanistic analyses. KEY FINDINGS Supplementation with AdA from larval stages L1 to L4 impaired neurobehavioral development, such as locomotive behaviors, foraging ability, chemotaxis behavior, and aggregation behavior. Furthermore, AdA upregulated the production of intracellular reactive oxygen species. AdA-induced oxidative stress blocked serotonin synthesis and serotoninergic neuron activity and inhibited expression of daf-16 and the daf-16-regulated genes mtl-1, mtl-2, sod-1, and sod-3, resulting in attenuation of the lifespan in C. elegans. SIGNIFICANCE Our study reveals that AdA is a harmful HBM lipid that may have adverse effects on infant adaptive behavioral development. We believe this information may be critical for AdA administration guidance in children's health care.
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Affiliation(s)
- Chia-Hsiu Wu
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Wen-Li Hsu
- Department of Dermatology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80145, Taiwan; Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Ching-Chung Tsai
- Department of Pediatrics, E-Da Hospital, No. 8, Yida Rd., Kaohsiung 82445, Taiwan; School of Medicine, College of Medicine, I-Shou University, Kaohsiung 82445, Taiwan
| | - How-Ran Chao
- Department of Environmental Science and Engineering, College of Engineering, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; Emerging Compounds Research Center, General Research Service Center, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; Institute of Food Safety Management, College of Agriculture, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan.
| | - Ching-Ying Wu
- Department of Dermatology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80145, Taiwan; Department of Cosmetic Science, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan.
| | - Yi-Hsuan Chen
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Yun-Ru Lai
- Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Chu-Huang Chen
- Vascular and Medicinal Research, The Texas Heart Institute, Houston, TX 77030, USA; New York Heart Research Foundation, Mineola, NY 11501, USA; Institute for Biomedical Sciences, Shinshu University, Nagano 390-8621, Japan.
| | - Ming-Hsien Tsai
- Department of Child Care, College of Humanities and Social Sciences, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan; Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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15
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Ding J, Peng L, Moon S, Lee HJ, Patel DS, Lu H. An expanded GCaMP reporter toolkit for functional imaging in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531342. [PMID: 36945463 PMCID: PMC10028802 DOI: 10.1101/2023.03.06.531342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
In living organisms, changes in calcium flux are integral to many different cellular functions and are especially critical for the activity of neurons and myocytes. Genetically encoded calcium indicators (GECIs) have been popular tools for reporting changes in calcium levels in vivo . In particular, GCaMP, derived from GFP, are the most widely used GECIs and have become an invaluable toolkit for neurophysiological studies. Recently, new variants of GCaMP, which offer a greater variety of temporal dynamics and improved brightness, have been developed. However, these variants are not readily available to the Caenorhabditis elegans research community. This work reports a set of GCaMP6 and jGCaMP7 reporters optimized for C. elegans studies. Our toolkit provides reporters with improved dynamic range, varied kinetics, and targeted subcellular localizations. Besides optimized routine uses, this set of reporters are also well-suited for studies requiring fast imaging speeds and low magnification or low-cost platforms.
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Affiliation(s)
- Jimmy Ding
- These authors contributed equally
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Lucinda Peng
- These authors contributed equally
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sihoon Moon
- These authors contributed equally
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyun Jee Lee
- These authors contributed equally
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Dhaval S. Patel
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Present address: NemaLife Inc, Lubbock, TX 79409, USA
| | - Hang Lu
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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16
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Lin A, Qin S, Casademunt H, Wu M, Hung W, Cain G, Tan NZ, Valenzuela R, Lesanpezeshki L, Venkatachalam V, Pehlevan C, Zhen M, Samuel AD. Functional imaging and quantification of multineuronal olfactory responses in C. elegans. SCIENCE ADVANCES 2023; 9:eade1249. [PMID: 36857454 PMCID: PMC9977185 DOI: 10.1126/sciadv.ade1249] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 02/01/2023] [Indexed: 05/21/2023]
Abstract
Many animals perceive odorant molecules by collecting information from ensembles of olfactory neurons, where each neuron uses receptors that are tuned to recognize certain odorant molecules with different binding affinity. Olfactory systems are able, in principle, to detect and discriminate diverse odorants using combinatorial coding strategies. We have combined microfluidics and multineuronal imaging to study the ensemble-level olfactory representations at the sensory periphery of the nematode Caenorhabditis elegans. The collective activity of C. elegans chemosensory neurons reveals high-dimensional representations of olfactory information across a broad space of odorant molecules. We reveal diverse tuning properties and dose-response curves across chemosensory neurons and across odorants. We describe the unique contribution of each sensory neuron to an ensemble-level code for volatile odorants. We show that a natural stimuli, a set of nematode pheromones, are also encoded by the sensory ensemble. The integrated activity of the C. elegans chemosensory neurons contains sufficient information to robustly encode the intensity and identity of diverse chemical stimuli.
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Affiliation(s)
- Albert Lin
- Department of Physics, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Shanshan Qin
- Center for Brain Science, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Helena Casademunt
- Department of Physics, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Min Wu
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Gregory Cain
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Nicolas Z. Tan
- Department of Physics, Northeastern University, Boston, MA, USA
| | | | - Leila Lesanpezeshki
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | | | - Cengiz Pehlevan
- Center for Brain Science, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Aravinthan D.T. Samuel
- Department of Physics, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
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17
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Brandel-Ankrapp KL, Arey RN. Uncovering novel regulators of memory using C. elegans genetic and genomic analysis. Biochem Soc Trans 2023; 51:161-171. [PMID: 36744642 PMCID: PMC10518207 DOI: 10.1042/bst20220455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/20/2022] [Accepted: 01/19/2023] [Indexed: 02/07/2023]
Abstract
How organisms learn and encode memory is an outstanding question in neuroscience research. Specifically, how memories are acquired and consolidated at the level of molecular and gene pathways remains unclear. In addition, memory is disrupted in a wide variety of neurological disorders; therefore, discovering molecular regulators of memory may reveal therapeutic targets for these disorders. C. elegans are an excellent model to uncover molecular and genetic regulators of memory. Indeed, the nematode's invariant neuronal lineage, fully mapped genome, and conserved associative behaviors have allowed the development of a breadth of genetic and genomic tools to examine learning and memory. In this mini-review, we discuss novel and exciting genetic and genomic techniques used to examine molecular and genetic underpinnings of memory from the level of the whole-worm to tissue-specific and cell-type specific approaches with high spatiotemporal resolution.
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Affiliation(s)
- Katie L. Brandel-Ankrapp
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, U.S.A
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Rachel N. Arey
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX 77030, U.S.A
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, U.S.A
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18
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Wu N, Chen YA, Zhu Q, Son CH, Gu KZ, Zou CG, Wu QY, Ma YC. The EGL-30 pathway regulates experience-dependent aversive behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa. Biochem Biophys Res Commun 2023; 642:107-112. [PMID: 36566561 DOI: 10.1016/j.bbrc.2022.12.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Avoidance of harmful substances is survival strategy used cross invertebrates and vertebrates. For example, the nematode Caenorhabditis elegans evolves a sufficient avoidance response to pathogenic bacteria. Despite G protein has been found to exert neural plasticity for avoidance behaviours in C. elegans, the function of Gi/o and Gq subunit signalling in experience-dependent aversive behaviour remains unclear. In this study, we show that EGL-30/Gq coupled with EGL-8/UNC-13 regulates aversive behaviour of C. elegans to pathogenic bacterium Pseudomonas aeruginosa PA01 via acetylcholine and its receptor nAChR. Pyocyanin, a toxin secreted from P. aeruginosa, acts as a signal molecule to trigger aversive behaviour. ODR-3 and ODR-7 in AWA and AWC neurons function as upstream of EGL-30 to induce experience-dependent aversive behaviour to P. aeruginosa, respectively. These results suggested that a novel signalling pathway to regulate a behavioural response.
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Affiliation(s)
- Nan Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Yu-An Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qian Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cai-Hua Son
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Kun-Ze Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cheng-Gang Zou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qin-Yi Wu
- Yunnan Provincial Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Chinese Medicine, Kunming, 650500, Yunnan, China.
| | - Yi-Cheng Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China.
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19
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Worms exposed to virulent bacteria show changes in social behaviour. Nature 2023:10.1038/d41586-022-04224-z. [PMID: 36599998 DOI: 10.1038/d41586-022-04224-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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20
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Wu T, Ge M, Wu M, Duan F, Liang J, Chen M, Gracida X, Liu H, Yang W, Dar AR, Li C, Butcher RA, Saltzman AL, Zhang Y. Pathogenic bacteria modulate pheromone response to promote mating. Nature 2023; 613:324-331. [PMID: 36599989 PMCID: PMC10732163 DOI: 10.1038/s41586-022-05561-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 11/11/2022] [Indexed: 01/05/2023]
Abstract
Pathogens generate ubiquitous selective pressures and host-pathogen interactions alter social behaviours in many animals1-4. However, very little is known about the neuronal mechanisms underlying pathogen-induced changes in social behaviour. Here we show that in adult Caenorhabditis elegans hermaphrodites, exposure to a bacterial pathogen (Pseudomonas aeruginosa) modulates sensory responses to pheromones by inducing the expression of the chemoreceptor STR-44 to promote mating. Under standard conditions, C. elegans hermaphrodites avoid a mixture of ascaroside pheromones to facilitate dispersal5-13. We find that exposure to the pathogenic Pseudomonas bacteria enables pheromone responses in AWA sensory neurons, which mediate attractive chemotaxis, to suppress the avoidance. Pathogen exposure induces str-44 expression in AWA neurons, a process regulated by a transcription factor zip-5 that also displays a pathogen-induced increase in expression in AWA. STR-44 acts as a pheromone receptor and its function in AWA neurons is required for pathogen-induced AWA pheromone response and suppression of pheromone avoidance. Furthermore, we show that C. elegans hermaphrodites, which reproduce mainly through self-fertilization, increase the rate of mating with males after pathogen exposure and that this increase requires str-44 in AWA neurons. Thus, our results uncover a causal mechanism for pathogen-induced social behaviour plasticity, which can promote genetic diversity and facilitate adaptation of the host animals.
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Affiliation(s)
- Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Minghai Ge
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Min Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Jingting Liang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Maoting Chen
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Xicotencatl Gracida
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Chengyin Li
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Arneet L Saltzman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
- Center for Brain Science, Harvard University, Cambridge, MA, USA.
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21
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Chen YJ, Pan CL. An olfactory-interneuron circuit that drives stress-induced avoidance behavior in C. elegans. Neurosci Res 2022; 191:91-97. [PMID: 36565857 DOI: 10.1016/j.neures.2022.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 11/23/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Physiological stress represents a drastic change of internal state and can drive avoidance behavior, but the neural circuits are incompletely defined. Here, we characterize a sensory-interneuron circuit for mitochondrial stress-induced avoidance behavior in C. elegans. The olfactory sensory neurons and the AIY interneuron are essential, with the olfactory neurons acting upstream of AIY. Unlike pathogen avoidance, stress-induced avoidance does not require AIB, AIZ or RIA interneurons. Ablation or inhibition of the head motor neurons SMDD/V alters the worm's locomotion and reduces avoidance. These findings substantiate our understanding of the circuit mechanisms that underlie learned avoidance behavior triggered by mitochondrial stress.
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Affiliation(s)
- Yen-Ju Chen
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan.
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22
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Filipowicz A, Lalsiamthara J, Aballay A. Dissection of a sensorimotor circuit underlying pathogen aversion in C. elegans. BMC Biol 2022; 20:229. [PMID: 36209082 PMCID: PMC9548130 DOI: 10.1186/s12915-022-01424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/28/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Altering animal behavior to reduce pathogen exposure is a key line of defense against pathogen attack. In Caenorhabditis elegans, alterations in intestinal physiology caused by pathogen colonization and sensation of microbial metabolites may lead to activation of pathogen aversive behaviors ranging from aversive reflexes to learned avoidance. However, the neural circuitry between chemosensory neurons that sense pathogenic bacterial cues and the motor neurons responsible for avoidance-associated locomotion remains unknown. RESULTS Using C. elegans, we found that backward locomotion was a component of learned pathogen avoidance, as animals pre-exposed to Pseudomonas aeruginosa or Enterococcus faecalis showed reflexive aversion to drops of the bacteria driven by chemosensory neurons, including the olfactory AWB neurons. This response also involved intestinal distention and, for E. faecalis, required expression of TRPM channels in the intestine and excretory system. Additionally, we uncovered a circuit composed of olfactory neurons, interneurons, and motor neurons that controls the backward locomotion crucial for learned reflexive aversion to pathogenic bacteria, learned avoidance, and the repulsive odor 2-nonanone. CONCLUSIONS Using whole-brain simulation and functional assays, we uncovered a novel sensorimotor circuit governing learned reflexive aversion. The discovery of a complete sensorimotor circuit for reflexive aversion demonstrates the utility of using the C. elegans connectome and computational modeling in uncovering new neuronal regulators of behavior.
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Affiliation(s)
- Adam Filipowicz
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, 97239, USA
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Jonathan Lalsiamthara
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, 97239, USA.
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23
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Khan M, Hartmann AH, O’Donnell MP, Piccione M, Pandey A, Chao PH, Dwyer ND, Bargmann CI, Sengupta P. Context-dependent reversal of odorant preference is driven by inversion of the response in a single sensory neuron type. PLoS Biol 2022; 20:e3001677. [PMID: 35696430 PMCID: PMC9232122 DOI: 10.1371/journal.pbio.3001677] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 06/24/2022] [Accepted: 05/16/2022] [Indexed: 11/18/2022] Open
Abstract
The valence and salience of individual odorants are modulated by an animal’s innate preferences, learned associations, and internal state, as well as by the context of odorant presentation. The mechanisms underlying context-dependent flexibility in odor valence are not fully understood. Here, we show that the behavioral response of Caenorhabditis elegans to bacterially produced medium-chain alcohols switches from attraction to avoidance when presented in the background of a subset of additional attractive chemicals. This context-dependent reversal of odorant preference is driven by cell-autonomous inversion of the response to these alcohols in the single AWC olfactory neuron pair. We find that while medium-chain alcohols inhibit the AWC olfactory neurons to drive attraction, these alcohols instead activate AWC to promote avoidance when presented in the background of a second AWC-sensed odorant. We show that these opposing responses are driven via engagement of distinct odorant-directed signal transduction pathways within AWC. Our results indicate that context-dependent recruitment of alternative intracellular signaling pathways within a single sensory neuron type conveys opposite hedonic valences, thereby providing a robust mechanism for odorant encoding and discrimination at the periphery.
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Affiliation(s)
- Munzareen Khan
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Anna H. Hartmann
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Michael P. O’Donnell
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Madeline Piccione
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Anjali Pandey
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Pin-Hao Chao
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Noelle D. Dwyer
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | | | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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24
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A serotonergic circuit regulates aversive associative learning under mitochondrial stress in
C. elegans. Proc Natl Acad Sci U S A 2022; 119:e2115533119. [PMID: 35254908 PMCID: PMC8931235 DOI: 10.1073/pnas.2115533119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Significance
Physiological stress triggers avoidance behavior, allowing the animals to stay away from potential threats and optimize their chance of survival. Mitochondrial disruption, a common physiological stress in diverse species, induces the nematode
Caenorhabditis elegans
to avoid non-pathogenic bacteria through a serotonergic neuronal circuit. We find that distinct neurons, communicated through serotonin and a specific serotonin receptor, are required for the formation and retrieval of this learned aversive behavior. This learned avoidance behavior is associated with increased serotonin synthesis, altered neuronal response property, and reprogramming of locomotion patterns. The circuit and neuromodulatory mechanisms described here offer important insights for stress-induced avoidance behavior.
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25
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Abstract
There is no agreement on whether any invertebrates are conscious and no agreement on a methodology that could settle the issue. How can the debate move forward? I distinguish three broad types of approach: theory-heavy, theory-neutral and theory-light. Theory-heavy and theory-neutral approaches face serious problems, motivating a middle path: the theory-light approach. At the core of the theory-light approach is a minimal commitment about the relation between phenomenal consciousness and cognition that is compatible with many specific theories of consciousness: the hypothesis that phenomenally conscious perception of a stimulus facilitates, relative to unconscious perception, a cluster of cognitive abilities in relation to that stimulus. This "facilitation hypothesis" can productively guide inquiry into invertebrate consciousness. What is needed? At this stage, not more theory, and not more undirected data gathering. What is needed is a systematic search for consciousness-linked cognitive abilities, their relationships to each other, and their sensitivity to masking.
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26
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Liu H, Wu T, Canales XG, Wu M, Choi MK, Duan F, Calarco JA, Zhang Y. Forgetting generates a novel state that is reactivatable. SCIENCE ADVANCES 2022; 8:eabi9071. [PMID: 35148188 PMCID: PMC8836790 DOI: 10.1126/sciadv.abi9071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 12/21/2021] [Indexed: 05/21/2023]
Abstract
Forgetting is defined as a time-dependent decline of a memory. However, it is not clear whether forgetting reverses the learning process to return the brain to the naive state. Here, using the aversive olfactory learning of pathogenic bacteria in C. elegans, we show that forgetting generates a novel state of the nervous system that is distinct from the naive state or the learned state. A transient exposure to the training condition or training odorants reactivates this novel state to elicit the previously learned behavior. An AMPA receptor and a type II serotonin receptor act in the central neuron of the learning circuit to decrease and increase the speed to reach this novel state, respectively. Together, our study systematically characterizes forgetting and uncovers conserved mechanisms underlying the rate of forgetting.
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Affiliation(s)
- He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Xicotencatl Gracida Canales
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Min Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - John A. Calarco
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
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27
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Yang W, Wu T, Tu S, Qin Y, Shen C, Li J, Choi MK, Duan F, Zhang Y. Redundant neural circuits regulate olfactory integration. PLoS Genet 2022; 18:e1010029. [PMID: 35100258 PMCID: PMC8830790 DOI: 10.1371/journal.pgen.1010029] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 02/10/2022] [Accepted: 01/11/2022] [Indexed: 11/18/2022] Open
Abstract
Olfactory integration is important for survival in a natural habitat. However, how the nervous system processes signals of two odorants present simultaneously to generate a coherent behavioral response is poorly understood. Here, we characterize circuit basis for a form of olfactory integration in Caenorhabditis elegans. We find that the presence of a repulsive odorant, 2-nonanone, that signals threat strongly blocks the attraction of other odorants, such as isoamyl alcohol (IAA) or benzaldehyde, that signal food. Using a forward genetic screen, we found that genes known to regulate the structure and function of sensory neurons, osm-5 and osm-1, played a critical role in the integration process. Loss of these genes mildly reduces the response to the repellent 2-nonanone and disrupts the integration effect. Restoring the function of OSM-5 in either AWB or ASH, two sensory neurons known to mediate 2-nonanone-evoked avoidance, is sufficient to rescue. Sensory neurons AWB and downstream interneurons AVA, AIB, RIM that play critical roles in olfactory sensorimotor response are able to process signals generated by 2-nonanone or IAA or the mixture of the two odorants and contribute to the integration. Thus, our results identify redundant neural circuits that regulate the robust effect of a repulsive odorant to block responses to attractive odorants and uncover the neuronal and cellular basis for this complex olfactory task. In their natural environment, animals, including humans, encounter complex olfactory stimuli. Thus, how the brain processes multiple sensory cues to generate a coherent behavioral output is critical for the survival of the animal. In the present study, we combined molecular cellular genetics, optical physiology and behavioral analysis to study a common olfactory phenomenon in which the presence of one odorant blocks the response to another. Our results show that the integrated response is regulated by redundant neuronal circuits that engage several interneurons essential for olfactory sensorimotor responses, a mechanism that likely ensures a robust behavioral response to sensory cues representing information critical for survival.
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Affiliation(s)
- Wenxing Yang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
- * E-mail: (WY); (YZ)
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Shasha Tu
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Yuang Qin
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Chengchen Shen
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Jiangyun Li
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (WY); (YZ)
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28
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Schiffer JA, Stumbur SV, Seyedolmohadesin M, Xu Y, Serkin WT, McGowan NG, Banjo O, Torkashvand M, Lin A, Hosea CN, Assié A, Samuel BS, O’Donnell MP, Venkatachalam V, Apfeld J. Modulation of sensory perception by hydrogen peroxide enables Caenorhabditis elegans to find a niche that provides both food and protection from hydrogen peroxide. PLoS Pathog 2021; 17:e1010112. [PMID: 34941962 PMCID: PMC8699984 DOI: 10.1371/journal.ppat.1010112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/14/2021] [Indexed: 02/07/2023] Open
Abstract
Hydrogen peroxide (H2O2) is the most common chemical threat that organisms face. Here, we show that H2O2 alters the bacterial food preference of Caenorhabditis elegans, enabling the nematodes to find a safe environment with food. H2O2 induces the nematodes to leave food patches of laboratory and microbiome bacteria when those bacterial communities have insufficient H2O2-degrading capacity. The nematode's behavior is directed by H2O2-sensing neurons that promote escape from H2O2 and by bacteria-sensing neurons that promote attraction to bacteria. However, the input for H2O2-sensing neurons is removed by bacterial H2O2-degrading enzymes and the bacteria-sensing neurons' perception of bacteria is prevented by H2O2. The resulting cross-attenuation provides a general mechanism that ensures the nematode's behavior is faithful to the lethal threat of hydrogen peroxide, increasing the nematode's chances of finding a niche that provides both food and protection from hydrogen peroxide.
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Affiliation(s)
- Jodie A. Schiffer
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Stephanie V. Stumbur
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Maedeh Seyedolmohadesin
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Yuyan Xu
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - William T. Serkin
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Natalie G. McGowan
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Oluwatosin Banjo
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Mahdi Torkashvand
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Albert Lin
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ciara N. Hosea
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Adrien Assié
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Buck S. Samuel
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael P. O’Donnell
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Vivek Venkatachalam
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Javier Apfeld
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
- Bioengineering Department, Northeastern University, Boston, Massachusetts, United States of America
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29
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Cheng H, Liu Y, Xue Y, Shao J, Tan Z, Liu S, Duan S, Kang L. Molecular Strategies for Intensity-Dependent Olfactory Processing in Caenorhabditis elegans. Front Mol Neurosci 2021; 14:748214. [PMID: 34803606 PMCID: PMC8600271 DOI: 10.3389/fnmol.2021.748214] [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] [Received: 07/27/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Various odorants trigger complex animal behaviors across species in both quality- and quantity-dependent manners. However, how the intensity of olfactory input is encoded remains largely unknown. Here we report that isoamyl alcohol (IAA) induces bi-directional currents through a Gα- guanylate cyclase (GC)- cGMP signaling pathway in Caenorhabditis elegans olfactory neuron amphid wing “C” cell (AWC), while two opposite cGMP signaling pathways are responsible for odor-sensing in olfactory neuron amphid wing “B” cell (AWB): (1) a depolarizing Gα (GPA-3)- phosphodiesterase (PDE) – cGMP pathway which can be activated by low concentrations of isoamyl alcohol (IAA), and (2) a hyperpolarizing Gα (ODR-3)- GC- cGMP pathway sensing high concentrations of IAA. Besides, IAA induces Gα (ODR-3)-TRPV(OSM-9)-dependent currents in amphid wing “A” cell (AWA) and amphid neuron “H” cell with single ciliated sensory ending (ASH) neurons with different thresholds. Our results demonstrate that an elaborate combination of multiple signaling machineries encode the intensity of olfactory input, shedding light on understanding the molecular strategies on sensory transduction.
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Affiliation(s)
- Hankui Cheng
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yu Liu
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yadan Xue
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiajie Shao
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhibing Tan
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyan Liu
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.,Department of Neurology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lijun Kang
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
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30
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Sordillo A, Bargmann CI. Behavioral control by depolarized and hyperpolarized states of an integrating neuron. eLife 2021; 10:e67723. [PMID: 34738904 PMCID: PMC8570696 DOI: 10.7554/elife.67723] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 10/19/2021] [Indexed: 12/11/2022] Open
Abstract
Coordinated transitions between mutually exclusive motor states are central to behavioral decisions. During locomotion, the nematode Caenorhabditis elegans spontaneously cycles between forward runs, reversals, and turns with complex but predictable dynamics. Here, we provide insight into these dynamics by demonstrating how RIM interneurons, which are active during reversals, act in two modes to stabilize both forward runs and reversals. By systematically quantifying the roles of RIM outputs during spontaneous behavior, we show that RIM lengthens reversals when depolarized through glutamate and tyramine neurotransmitters and lengthens forward runs when hyperpolarized through its gap junctions. RIM is not merely silent upon hyperpolarization: RIM gap junctions actively reinforce a hyperpolarized state of the reversal circuit. Additionally, the combined outputs of chemical synapses and gap junctions from RIM regulate forward-to-reversal transitions. Our results indicate that multiple classes of RIM synapses create behavioral inertia during spontaneous locomotion.
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Affiliation(s)
- Aylesse Sordillo
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller UniversityNew YorkUnited States
| | - Cornelia I Bargmann
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller UniversityNew YorkUnited States
- Chan Zuckerberg InitiativeRedwood CityUnited States
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31
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Morud J, Hardege I, Liu H, Wu T, Choi MK, Basu S, Zhang Y, Schafer WR. Deorphanization of novel biogenic amine-gated ion channels identifies a new serotonin receptor for learning. Curr Biol 2021; 31:4282-4292.e6. [PMID: 34388373 PMCID: PMC8536830 DOI: 10.1016/j.cub.2021.07.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/09/2021] [Accepted: 07/15/2021] [Indexed: 11/16/2022]
Abstract
Pentameric ligand-gated ion channels (LGICs) play conserved, critical roles in both excitatory and inhibitory synaptic transmission and can be activated by diverse neurochemical ligands. We have performed a characterization of orphan channels from the nematode C. elegans, identifying five new monoamine-gated LGICs with diverse functional properties and expression postsynaptic to aminergic neurons. These include polymodal anion channels activated by both dopamine and tyramine, which may mediate inhibitory transmission by both molecules in vivo. Intriguingly, we also find that a novel serotonin-gated cation channel, LGC-50, is essential for aversive olfactory learning of pathogenic bacteria, a process known to depend on serotonergic neurotransmission. Remarkably, the redistribution of LGC-50 to neuronal processes is modulated by olfactory conditioning, and lgc-50 point mutations that cause misregulation of receptor membrane expression interfere with olfactory learning. Thus, the intracellular trafficking and localization of these receptors at synapses may represent a molecular cornerstone of the learning mechanism.
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Affiliation(s)
- Julia Morud
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Iris Hardege
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Centre for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Centre for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Centre for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Swaraj Basu
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Medicinaregatan 9A, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Centre for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - William R Schafer
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
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32
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Yu AJ, Rankin CH. Neurobiology: From genome and connectome to understanding behavior. Curr Biol 2021; 31:R1135-R1138. [PMID: 34637717 DOI: 10.1016/j.cub.2021.08.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Many forms of synaptic plasticity are mediated by changes in the abundance, density, and expression levels of postsynaptic ionotropic receptors. A new study identifies the endogenous ligands of five 'orphan' aminergic ligand-gated ion channels in Caenorhabditis elegans, functionally characterizes these channels, and explores the role of one of them in a simple form of learning.
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Affiliation(s)
- Alex J Yu
- Djavad Mowfaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Catharine H Rankin
- Djavad Mowfaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada.
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33
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Rahmani A, Chew YL. Investigating the molecular mechanisms of learning and memory using Caenorhabditis elegans. J Neurochem 2021; 159:417-451. [PMID: 34528252 DOI: 10.1111/jnc.15510] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/15/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022]
Abstract
Learning is an essential biological process for survival since it facilitates behavioural plasticity in response to environmental changes. This process is mediated by a wide variety of genes, mostly expressed in the nervous system. Many studies have extensively explored the molecular and cellular mechanisms underlying learning and memory. This review will focus on the advances gained through the study of the nematode Caenorhabditis elegans. C. elegans provides an excellent system to study learning because of its genetic tractability, in addition to its invariant, compact nervous system (~300 neurons) that is well-characterised at the structural level. Importantly, despite its compact nature, the nematode nervous system possesses a high level of conservation with mammalian systems. These features allow the study of genes within specific sensory-, inter- and motor neurons, facilitating the interrogation of signalling pathways that mediate learning via defined neural circuits. This review will detail how learning and memory can be studied in C. elegans through behavioural paradigms that target distinct sensory modalities. We will also summarise recent studies describing mechanisms through which key molecular and cellular pathways are proposed to affect associative and non-associative forms of learning.
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Affiliation(s)
- Aelon Rahmani
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Yee Lian Chew
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
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34
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Byrd DT, Jin Y. Wired for insight-recent advances in Caenorhabditis elegans neural circuits. Curr Opin Neurobiol 2021; 69:159-169. [PMID: 33957432 PMCID: PMC8387325 DOI: 10.1016/j.conb.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 11/15/2022]
Abstract
The completion of Caenorhabditis elegans connectomics four decades ago has long guided mechanistic investigation of neuronal circuits. Recent technological advances in microscopy and computation programs have aided re-examination of this connectomics, expanding our knowledge by both uncovering previously unreported synaptic connections and also generating models for neural networks underlying behaviors. Combining molecular information from single cell transcriptomes with elegant tools for cell-specific manipulation has further enhanced the ability to precisely investigate individual neurons in behaving animals. This mini-review aims to provide an overview of new information on connectomics and progress toward a molecular atlas of C. elegans nervous system, and discuss emerging findings on neuronal circuits.
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Affiliation(s)
- Dana T Byrd
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Yishi Jin
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA; Kavli Institute of Brain and Mind, University of California San Diego, La Jolla, CA, 92093, USA.
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35
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Sun G, Manning C, Lee GH, Majeed M, Lu H. Microswimmer Combing: Controlling Interfacial Dynamics for Open-Surface Multifunctional Screening of Small Animals. Adv Healthc Mater 2021; 10:e2001887. [PMID: 33890423 DOI: 10.1002/adhm.202001887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/13/2021] [Indexed: 12/31/2022]
Abstract
Image-based screening of multicellular model organisms is critical for both investigating fundamental biology and drug development. Current microfluidic techniques for high-throughput manipulation of small model organisms, although useful, are generally complicated to operate, which impedes their widespread adoption by biology laboratories. To address this challenge, this paper presents an ultrasimple and yet effective approach, "microswimmer combing," to rapidly isolate live small animals on an open-surface array. This approach exploits a dynamic contact line-combing mechanism designed to handle highly active microswimmers. The isolation method is robust, and the device operation is simple for users without a priori experience. The versatile open-surface device enables multiple screening applications, including high-resolution imaging of multicellular organisms, on-demand mutant selection, and multiplexed chemical screening. The simplicity and versatility of this method provide broad access to high-throughput experimentation for biologists and open up new opportunities to study active microswimmers by different scientific communities.
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Affiliation(s)
- Gongchen Sun
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332 USA
| | - Cassidy‐Arielle Manning
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Ga Hyun Lee
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Maryam Majeed
- Department of Biological Sciences Columbia University New York NY 10027 USA
| | - Hang Lu
- School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332 USA
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36
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Deficiency of innate immunity against P. aeruginosa enhances behavioral avoidance via the HECW-1/NPR-1 module in C. elegans. Infect Immun 2021; 89:e0006721. [PMID: 34310887 DOI: 10.1128/iai.00067-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To antagonize infection of pathogenic bacteria in soil and confer increased survival, Caenorhabditis elegans employs innate immunity and behavioral avoidance synchronously as the two main defensive strategies. Although both biological processes and their individual signaling pathways have been partially elucidated, knowledge of their interrelationship remains limited. The current study reveals that deficiency of innate immunity triggered by mutation of the classic immune gene pmk-1 promotes avoidance behavior in C. elegans; and vice versa. Restoration of pmk-1 expression using the tissue-specific promoters suggested that the functional loss of both intestinal and neuronal pmk-1 is necessary for the enhanced avoidance. Additionally, PMK-1 co-localized with the E3 ubiquitin ligase HECW-1 in OLL neurons and regulated the expressional level of the latter, which consequently affected the production of NPR-1, a G-protein-coupled receptor homologous to the mammalian neuropeptide Y receptor, in RMG neurons in a non-cell-autonomous manner. Collectively, our study illustrates, once the innate immunity is impaired when C. elegans antagonizes bacterial infection, the other defensive strategy of behavioral avoidance can be enhanced accordingly via the HECW-1/NPR-1 module, suggesting that GPCRs in neural circuits may receive the inputs from immune system and integrate those two systems for better adapting to the real-time status.
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37
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Prakash D, Ms A, Radhika B, Venkatesan R, Chalasani SH, Singh V. 1-Undecene from Pseudomonas aeruginosa is an olfactory signal for flight-or-fight response in Caenorhabditis elegans. EMBO J 2021; 40:e106938. [PMID: 34086368 PMCID: PMC8246062 DOI: 10.15252/embj.2020106938] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/06/2021] [Accepted: 04/15/2021] [Indexed: 11/09/2022] Open
Abstract
Animals possess conserved mechanisms to detect pathogens and to improve survival in their presence by altering their own behavior and physiology. Here, we utilize Caenorhabditis elegans as a model host to ask whether bacterial volatiles constitute microbe-associated molecular patterns. Using gas chromatography-mass spectrometry, we identify six prominent volatiles released by the bacterium Pseudomonas aeruginosa. We show that a specific volatile, 1-undecene, activates nematode odor sensory neurons inducing both flight and fight responses in worms. Using behavioral assays, we show that worms are repelled by 1-undecene and that this aversion response is driven by the detection of this volatile through AWB odor sensory neurons. Furthermore, we find that 1-undecene odor can induce immune effectors specific to P. aeruginosa via AWB neurons and that brief pre-exposure of worms to the odor enhances their survival upon subsequent bacterial infection. These results show that 1-undecene derived from P. aeruginosa serves as a pathogen-associated molecular pattern for the induction of protective responses in C. elegans.
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Affiliation(s)
- Deep Prakash
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Akhil Ms
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | | | - Radhika Venkatesan
- National Center of Biological Sciences, Bangalore, India.,Department of Biological Sciences, Indian Institute of Science Education and Research, Mohanpur, India
| | | | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
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38
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Filipowicz A, Lalsiamthara J, Aballay A. TRPM channels mediate learned pathogen avoidance following intestinal distention. eLife 2021; 10:65935. [PMID: 34032213 PMCID: PMC8177887 DOI: 10.7554/elife.65935] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
Upon exposure to harmful microorganisms, hosts engage in protective molecular and behavioral immune responses, both of which are ultimately regulated by the nervous system. Using the nematode Caenorhabditis elegans, we show that ingestion of Enterococcus faecalis leads to a fast pathogen avoidance behavior that results in aversive learning. We have identified multiple sensory mechanisms involved in the regulation of avoidance of E. faecalis. The G-protein coupled receptor NPR-1-dependent oxygen-sensing pathway opposes this avoidance behavior, while an ASE neuron-dependent pathway and an AWB and AWC neuron-dependent pathway are directly required for avoidance. Colonization of the anterior part of the intestine by E. faecalis leads to AWB and AWC mediated olfactory aversive learning. Finally, two transient receptor potential melastatin (TRPM) channels, GON-2 and GTL-2, mediate this newly described rapid pathogen avoidance. These results suggest a mechanism by which TRPM channels may sense the intestinal distension caused by bacterial colonization to elicit pathogen avoidance and aversive learning by detecting changes in host physiology.
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Affiliation(s)
- Adam Filipowicz
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Jonathan Lalsiamthara
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, United States
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39
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Manterola M, Palominos MF, Calixto A. The Heritability of Behaviors Associated With the Host Gut Microbiota. Front Immunol 2021; 12:658551. [PMID: 34054822 PMCID: PMC8155505 DOI: 10.3389/fimmu.2021.658551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
What defines whether the interaction between environment and organism creates a genetic memory able to be transferred to subsequent generations? Bacteria and the products of their metabolism are the most ubiquitous biotic environments to which every living organism is exposed. Both microbiota and host establish a framework where environmental and genetic factors are integrated to produce adaptive life traits, some of which can be inherited. Thus, the interplay between host and microbe is a powerful model to study how phenotypic plasticity is inherited. Communication between host and microbe can occur through diverse molecules such as small RNAs (sRNAs) and the RNA interference machinery, which have emerged as mediators and carriers of heritable environmentally induced responses. Notwithstanding, it is still unclear how the organism integrates sRNA signaling between different tissues to orchestrate a systemic bacterially induced response that can be inherited. Here we discuss current evidence of heritability produced by the intestinal microbiota from several species. Neurons and gut are the sensing systems involved in transmitting changes through transcriptional and post-transcriptional modifications to the gonads. Germ cells express inflammatory receptors, and their development and function are regulated by host and bacterial metabolites and sRNAs thus suggesting that the dynamic interplay between host and microbe underlies the host's capacity to transmit heritable behaviors. We discuss how the host detects changes in the microbiota that can modulate germ cells genomic functions. We also explore the nature of the interactions that leave permanent or long-term memory in the host and propose mechanisms by which the microbiota can regulate the development and epigenetic reprogramming of germ cells, thus influencing the inheritance of the host. We highlight the vast contribution of the bacterivore nematode C. elegans and its commensal and pathogenic bacteria to the understanding on how behavioral adaptations can be inter and transgenerational inherited.
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Affiliation(s)
- Marcia Manterola
- Programa de Genética Humana, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - M. Fernanda Palominos
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
- Programa de Doctorado en Ciencias, mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
| | - Andrea Calixto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
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40
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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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41
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Garcia-Sanchez JA, Ewbank JJ, Visvikis O. Ubiquitin-related processes and innate immunity in C. elegans. Cell Mol Life Sci 2021; 78:4305-4333. [PMID: 33630111 PMCID: PMC11072174 DOI: 10.1007/s00018-021-03787-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/18/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023]
Abstract
Innate immunity is an evolutionary ancient defence strategy that serves to eliminate infectious agents while maintaining host health. It involves a complex network of sensors, signaling proteins and immune effectors that detect the danger, then relay and execute the immune programme. Post-translational modifications relying on conserved ubiquitin and ubiquitin-like proteins are an integral part of the system. Studies using invertebrate models of infection, such as the nematode Caenorhabditis elegans, have greatly contributed to our understanding of how ubiquitin-related processes act in immune sensing, regulate immune signaling pathways, and participate to host defence responses. This review highlights the interest of working with a genetically tractable model organism and illustrates how C. elegans has been used to identify ubiquitin-dependent immune mechanisms, discover novel ubiquitin-based resistance strategies that mediate pathogen clearance, and unravel the role of ubiquitin-related processes in tolerance, preserving host fitness during pathogen attack. Special emphasis is placed on processes that are conserved in mammals.
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Affiliation(s)
- Juan A Garcia-Sanchez
- INSERM, C3M, Côte D'Azur University, Nice, France
- INSERM, CNRS, CIML, Turing Centre for Living Systems, Aix-Marseille University, Marseille, France
| | - Jonathan J Ewbank
- INSERM, CNRS, CIML, Turing Centre for Living Systems, Aix-Marseille University, Marseille, France.
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42
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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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43
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Abstract
Although Caenorhabditis elegans has been used as a model host for studying host-pathogen interactions for more than 20 years, the mechanisms by which it identifies pathogens are not well understood. This is largely due to its lack of most known pattern recognition receptors (PRRs) that recognize pathogen-derived molecules. Recent behavioral research in C. elegans indicates that its nervous system plays a major role in microbe sensing. With the increasing integration of neurobiology in immunological research, future studies may find that neuronal detection of pathogens is an integral part of C. elegans-pathogen interactions. Similar to that of mammals, the C. elegans nervous system regulates its immune system to maintain immunological homeostasis. Studies in the nematode have revealed unprecedented details regarding the molecules, cells, and signaling pathways involved in neural regulation of immunity. Notably, some of the studies indicate that some neuroimmune regulatory circuits need not be "activated" by pathogen infection because they are tonically active and that there could be a predetermined set point for internal immunity, around which the nervous system adjusts immune responses to internal or external environmental changes. Here, we review recent progress on the roles of the C. elegans nervous system in pathogen detection and immune regulation. Because of its advantageous characteristics, we expect that the C. elegans model will be critical for deciphering complex neuroimmune signaling mechanisms that integrate and process multiple sensory cues.
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Affiliation(s)
- Yiyong Liu
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
- Genomics Core, Washington State University, Spokane, Washington, USA
| | - Jingru Sun
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
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44
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Moore RS, Kaletsky R, Murphy CT. Protocol for transgenerational learned pathogen avoidance behavior assays in Caenorhabditis elegans. STAR Protoc 2021; 2:100384. [PMID: 33748786 PMCID: PMC7960678 DOI: 10.1016/j.xpro.2021.100384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Animal experiences, including learned behaviors, can be passed down to several generations of progeny in a phenomenon known as transgenerational epigenetic inheritance. Yet, little is known regarding the molecular mechanisms regulating physiologically relevant transgenerational memories. Here, we present a method for Caenorhabditis elegans in which worms learn to avoid the pathogen Pseudomonas aeruginosa (PA14). Unlike previous protocols, this training paradigm, either using PA14 lawns or through exposure to a PA14 small RNA (P11), induces memory in four generations of progeny. For complete details on the use and execution of this protocol, please refer to Moore et al. (2019) and Kaletsky et al. (2020). Protocol for C. elegans transgenerational pathogen avoidance memory training Trained worms are tested for pathogen avoidance learning using choice assays Several generations of progeny from trained mothers are propagated and tested
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Affiliation(s)
- Rebecca S Moore
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rachel Kaletsky
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.,LSI Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Coleen T Murphy
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.,LSI Genomics, Princeton University, Princeton, NJ 08544, USA
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45
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Yan J, Zhao N, Yang Z, Li Y, Bai H, Zou W, Zhang K, Huang X. A trade-off switch of two immunological memories in Caenorhabditis elegans reinfected by bacterial pathogens. J Biol Chem 2020; 295:17323-17336. [PMID: 33051209 PMCID: PMC7863904 DOI: 10.1074/jbc.ra120.013923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/25/2020] [Indexed: 11/06/2022] Open
Abstract
Recent studies have suggested that innate immune responses exhibit characteristics associated with memory linked to modulations in both vertebrates and invertebrates. However, the diverse evolutionary paths taken, particularly within the invertebrate taxa, should lead to similarly diverse innate immunity memory processes. Our understanding of innate immune memory in invertebrates primarily comes from studies of the fruit fly Drosophila melanogaster, the generality of which is unclear. Caenorhabditis elegans typically inhabits soil harboring a variety of fatal microbial pathogens; for this invertebrate, the innate immune system and aversive behavior are the major defensive strategies against microbial infection. However, their characteristics of immunological memory remains infantile. Here we discovered an immunological memory that promoted avoidance and suppressed innate immunity during reinfection with bacteria, which we revealed to be specific to the previously exposed pathogens. During this trade-off switch of avoidance and innate immunity, the chemosensory neurons AWB and ADF modulated production of serotonin and dopamine, which in turn decreased expression of the innate immunity-associated genes and led to enhanced avoidance via the downstream insulin-like pathway. Therefore, our current study profiles the immune memories during C. elegans reinfected by pathogenic bacteria and further reveals that the chemosensory neurons, the neurotransmitter(s), and their associated molecular signaling pathways are responsible for a trade-off switch between the two immunological memories.
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Affiliation(s)
- Jinyuan Yan
- State Key Lab for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China; Center Laboratory of the Second Hospital, Kunming Medical University, Kunming, Yunnan, China
| | - Ninghui Zhao
- Neurosurgery of the Second Hospital, Kunming Medical University, Kunming, Yunnan, China
| | - Zhongshan Yang
- Faculty of Basic Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan, China
| | - Yuhong Li
- State Key Lab for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Hua Bai
- State Key Lab for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China; School of Public Health, Kunming Medical University, Kunming, Yunnan, China
| | - Wei Zou
- School of Public Health, Kunming Medical University, Kunming, Yunnan, China
| | - Keqin Zhang
- State Key Lab for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China
| | - Xiaowei Huang
- State Key Lab for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China.
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46
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Fenyves BG, Arnold A, Gharat VG, Haab C, Tishinov K, Peter F, de Quervain D, Papassotiropoulos A, Stetak A. Dual Role of an mps-2/KCNE-Dependent Pathway in Long-Term Memory and Age-Dependent Memory Decline. Curr Biol 2020; 31:527-539.e7. [PMID: 33259792 DOI: 10.1016/j.cub.2020.10.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/14/2020] [Accepted: 10/21/2020] [Indexed: 01/24/2023]
Abstract
Activity-dependent persistent changes in neuronal intrinsic excitability and synaptic strength are underlying learning and memory. Voltage-gated potassium (Kv) channels are potential regulators of memory and may be linked to age-dependent neuronal disfunction. MinK-related peptides (MiRPs) are conserved transmembrane proteins modulating Kv channels; however, their possible role in the regulation of memory and age-dependent memory decline are unknown. Here, we show that, in C. elegans, mps-2 is the sole member of the MiRP family that controls exclusively long-term associative memory (LTAM) in AVA neuron. In addition, we demonstrate that mps-2 also plays a critical role in age-dependent memory decline. In young adult worms, mps-2 is transcriptionally upregulated by CRH-1/cyclic AMP (cAMP)-response-binding protein (CREB) during LTAM, although the mps-2 baseline expression is CREB independent and instead, during aging, relies on nhr-66, which acts as an age-dependent repressor. Deletion of nhr-66 or its binding element in the mps-2 promoter prevents age-dependent transcriptional repression of mps-2 and memory decline. Finally, MPS-2 acts through the modulation of the Kv2.1/KVS-3 and Kv2.2/KVS-4 heteromeric potassium channels. Altogether, we describe a conserved MPS-2/KVS-3/KVS-4 pathway essential for LTAM and also for a programmed control of physiological age-dependent memory decline.
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Affiliation(s)
- Bank G Fenyves
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Department of Molecular Biology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary
| | - Andreas Arnold
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland
| | - Vaibhav G Gharat
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland
| | - Carmen Haab
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland
| | - Kiril Tishinov
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Fabian Peter
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland
| | - Dominique de Quervain
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Cognitive Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; University Psychiatric Clinics, University of Basel, Wilhelm Klein-Strasse 27, 4055 Basel, Switzerland
| | - Andreas Papassotiropoulos
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Biozentrum, Life Sciences Training Facility, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland; University Psychiatric Clinics, University of Basel, Wilhelm Klein-Strasse 27, 4055 Basel, Switzerland
| | - Attila Stetak
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; Division of Molecular Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, 4055 Basel, Switzerland; University Psychiatric Clinics, University of Basel, Wilhelm Klein-Strasse 27, 4055 Basel, Switzerland.
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47
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Takeishi A, Yeon J, Harris N, Yang W, Sengupta P. Feeding state functionally reconfigures a sensory circuit to drive thermosensory behavioral plasticity. eLife 2020; 9:e61167. [PMID: 33074105 PMCID: PMC7644224 DOI: 10.7554/elife.61167] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/18/2020] [Indexed: 12/24/2022] Open
Abstract
Internal state alters sensory behaviors to optimize survival strategies. The neuronal mechanisms underlying hunger-dependent behavioral plasticity are not fully characterized. Here we show that feeding state alters C. elegans thermotaxis behavior by engaging a modulatory circuit whose activity gates the output of the core thermotaxis network. Feeding state does not alter the activity of the core thermotaxis circuit comprised of AFD thermosensory and AIY interneurons. Instead, prolonged food deprivation potentiates temperature responses in the AWC sensory neurons, which inhibit the postsynaptic AIA interneurons to override and disrupt AFD-driven thermotaxis behavior. Acute inhibition and activation of AWC and AIA, respectively, restores negative thermotaxis in starved animals. We find that state-dependent modulation of AWC-AIA temperature responses requires INS-1 insulin-like peptide signaling from the gut and DAF-16/FOXO function in AWC. Our results describe a mechanism by which functional reconfiguration of a sensory network via gut-brain signaling drives state-dependent behavioral flexibility.
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Affiliation(s)
- Asuka Takeishi
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Jihye Yeon
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Nathan Harris
- Department of Biology, Brandeis UniversityWalthamUnited States
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard UniversityCambridgeUnited States
| | - Piali Sengupta
- Department of Biology, Brandeis UniversityWalthamUnited States
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48
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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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49
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How Bacteria Impact Host Nervous System and Behaviors: Lessons from Flies and Worms. Trends Neurosci 2020; 43:998-1010. [PMID: 33051027 DOI: 10.1016/j.tins.2020.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/01/2020] [Accepted: 09/16/2020] [Indexed: 12/12/2022]
Abstract
Behavior is the neuronally controlled, voluntary or involuntary response of an organism to its environment. An increasing body of evidence indicates that microbes, which live closely associated with animals or in their immediate surroundings, significantly influence animals' behavior. The extreme complexity of the nervous system of animals, combined with the extraordinary microbial diversity, are two major obstacles to understand, at the molecular level, how microbes modulate animal behavior. In this review, we discuss recent advances in dissecting the impact that bacteria have on the nervous system of two genetically tractable invertebrate models, Drosophila melanogaster and Caenorhabditis elegans.
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50
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Liu X, Jiang L, Li L, Yu H, Nie S, Xie M, Gong J. The Role of Neurotransmitters in the Protection of Caenorhabditis Elegans for Salmonella Infection by Lactobacillus. Front Cell Infect Microbiol 2020; 10:554052. [PMID: 33134188 PMCID: PMC7550654 DOI: 10.3389/fcimb.2020.554052] [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: 04/23/2020] [Accepted: 08/20/2020] [Indexed: 12/20/2022] Open
Abstract
Salmonellosis is a common foodborne disease. We previously reported the protection of Caenorhabditis elegans from Salmonella Typhimurium DT104 infection by Lactobacillus zeae LB1. However, the mechanism is not fully understood. C. elegans exhibits behavior plasticity when presented with diverse pathogenic or commensal bacteria. Whether it can exert approach avoidance to S. Typhimurium through altering its neurological activity remains to be determined. In the current study, both the wild type and mutants defective in serotonin or dopamine production of C. elegans were used to investigate olfactory preference of the nematode to L. zeae LB1, DT104, and Escherichia coli OP50 by choice assays, and its resistance to DT104 infection and the protection offered by L. zeae LB1 using a life-span assay. The expression of target genes in C. elegans was also examined by real-time quantitative PCR. Results showed that pre-exposure to L. zeae LB1 did not elicit aversive olfactory behavior of the nematode toward DT104. Both mutants tph-1 and cat-2 succumbed faster than the wild type when infected with DT104. While pre-exposure to L. zeae LB1 significantly increased the survival of both the wild type and mutant tph-1, it provided no protection to mutant cat-2. Supplementation of dopamine resulted in both the resistance of mutant cat-2 to S. Typhimurium infection and the protection from L. zeae LB1 to the same mutant. Gene expression data also supported the observations in the life-span assay. These results suggest that both serotonin and dopamine play a positive role in the host defense of C. elegans to S. Typhimurium infection and that the L. zeae LB1 protection is not dependent on modifying olfactory preference of the nematode but mediated by dopamine that may have involved the regulation of p38-mitogen-activated protein kinase and insulin/insulin-like growth factor signaling pathways.
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Affiliation(s)
- Xiaozhen Liu
- Engineering Research Center of Health Food Design & Nutrition Regulation, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan, China.,Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph, ON, Canada.,State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Leming Jiang
- Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph, ON, Canada.,State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Linyan Li
- Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph, ON, Canada.,State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Hai Yu
- Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph, ON, Canada
| | - Shaoping Nie
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Mingyong Xie
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.,National R&D Center for Freshwater Fish Processing, Jiangxi Normal University, Nanchang, China
| | - Joshua Gong
- Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph, ON, Canada
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