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Kwon S, Park KS, Yoon KH. Regulator of Lipid Metabolism NHR-49 Mediates Pathogen Avoidance through Precise Control of Neuronal Activity. Cells 2024; 13:978. [PMID: 38891110 PMCID: PMC11172349 DOI: 10.3390/cells13110978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/24/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Precise control of neuronal activity is crucial for the proper functioning of neurons. How lipid homeostasis contributes to neuronal activity and how much of it is regulated by cells autonomously is unclear. In this study, we discovered that absence of the lipid regulator nhr-49, a functional ortholog of the peroxisome proliferator-activated receptor (PPAR) in Caenorhabditis elegans, resulted in defective pathogen avoidance behavior against Pseudomonas aeruginosa (PA14). Functional NHR-49 was required in the neurons, and more specifically, in a set of oxygen-sensing body cavity neurons, URX, AQR, and PQR. We found that lowering the neuronal activity of the body cavity neurons improved avoidance in nhr-49 mutants. Calcium imaging in URX neurons showed that nhr-49 mutants displayed longer-lasting calcium transients in response to an O2 upshift, suggesting that excess neuronal activity leads to avoidance defects. Cell-specific rescue of NHR-49 in the body cavity neurons was sufficient to improve pathogen avoidance, as well as URX neuron calcium kinetics. Supplementation with oleic acid also improved avoidance behavior and URX calcium kinetics, suggesting that the defective calcium response in the neuron is due to lipid dysfunction. These findings highlight the role of cell-autonomous lipid regulation in neuronal physiology and immune behavior.
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Affiliation(s)
- Saebom Kwon
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea;
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea;
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea
| | - Kyoung-hye Yoon
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju 26426, Republic of Korea
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2
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Wu Z, Cardona EA, Pierce JT. Non-apoptotic role of EGL-1 in exopher production and neuronal health in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.19.590348. [PMID: 38712027 PMCID: PMC11071422 DOI: 10.1101/2024.04.19.590348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
While traditionally studied for their pro-apoptotic functions, recent research suggests BH3-only proteins also have non-apoptotic roles. Here, we find that EGL-1, the BH3-only protein in Caenorhabditis elegans , promotes the cell-autonomous production of exophers in adult neurons. Exophers are large, micron-scale vesicles that are ejected from the cell and contain cellular components such as mitochondria. EGL-1 facilitates exopher production potentially through regulation of mitochondrial dynamics. Moreover, an endogenous, low level of EGL-1 expression appears to benefit dendritic health. Our findings provide insights into the mechanistic role of BH3-only protein in mitochondrial dynamics, downstream exopher production, and ultimately neuronal health. Significance statement BH3-only proteins were known for their function in inducing cell death. Their presence in healthy adult neurons, however, suggests additional roles. Our study focused on the BH3-only protein EGL-1 in the nematode Caenorhabditis elegans , where its apoptotic role was discovered. We reveal a new role in cell-autonomously promoting exopher production - a process where neurons extrude large vesicles containing potentially harmful cell contents. EGL-1 appears to promote this by regulating mitochondrial dynamics. We also report that low levels of EGL-1 benefit neuronal health and function. These findings expand our understanding of BH3-only proteins, mitochondrial dynamics, and exopher production in neurons and provide insights for neurodegenerative diseases.
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3
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Ripoll-Sánchez L, Watteyne J, Sun H, Fernandez R, Taylor SR, Weinreb A, Bentley BL, Hammarlund M, Miller DM, Hobert O, Beets I, Vértes PE, Schafer WR. The neuropeptidergic connectome of C. elegans. Neuron 2023; 111:3570-3589.e5. [PMID: 37935195 PMCID: PMC7615469 DOI: 10.1016/j.neuron.2023.09.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 08/02/2023] [Accepted: 09/29/2023] [Indexed: 11/09/2023]
Abstract
Efforts are ongoing to map synaptic wiring diagrams, or connectomes, to understand the neural basis of brain function. However, chemical synapses represent only one type of functionally important neuronal connection; in particular, extrasynaptic, "wireless" signaling by neuropeptides is widespread and plays essential roles in all nervous systems. By integrating single-cell anatomical and gene-expression datasets with biochemical analysis of receptor-ligand interactions, we have generated a draft connectome of neuropeptide signaling in the C. elegans nervous system. This network is characterized by high connection density, extended signaling cascades, autocrine foci, and a decentralized topology, with a large, highly interconnected core containing three constituent communities sharing similar patterns of input connectivity. Intriguingly, several key network hubs are little-studied neurons that appear specialized for peptidergic neuromodulation. We anticipate that the C. elegans neuropeptidergic connectome will serve as a prototype to understand how networks of neuromodulatory signaling are organized.
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Affiliation(s)
- Lidia Ripoll-Sánchez
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Psychiatry, Cambridge University, Cambridge, UK
| | - Jan Watteyne
- Department of Biology, KU Leuven, Leuven, Belgium
| | - HaoSheng Sun
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert Fernandez
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA
| | - Seth R Taylor
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Alexis Weinreb
- Departments of Genetics and Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Barry L Bentley
- Cardiff School of Technologies, Cardiff Metropolitan University, Cardiff, UK
| | - Marc Hammarlund
- Departments of Genetics and Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Oliver Hobert
- Department of Biological Sciences/HHMI, Columbia University, New York, NY, USA
| | - Isabel Beets
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Petra E Vértes
- Department of Psychiatry, Cambridge University, Cambridge, UK
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Biology, KU Leuven, Leuven, Belgium.
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4
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Le E, McCarthy T, Honer M, Curtin CE, Fingerut J, Nelson MD. The neuropeptide receptor npr-38 regulates avoidance and stress-induced sleep in Caenorhabditis elegans. Curr Biol 2023; 33:3155-3168.e9. [PMID: 37419114 DOI: 10.1016/j.cub.2023.06.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 05/19/2023] [Accepted: 06/14/2023] [Indexed: 07/09/2023]
Abstract
Although essential and conserved, sleep is not without its challenges that must be overcome; most notably, it renders animals vulnerable to threats in the environment. Infection and injury increase sleep demand, which dampens sensory responsiveness to stimuli, including those responsible for the initial insult. Stress-induced sleep in Caenorhabditis elegans occurs in response to cellular damage following noxious exposures the animals attempted to avoid. Here, we describe a G-protein-coupled receptor (GPCR) encoded by npr-38, which is required for stress-related responses including avoidance, sleep, and arousal. Overexpression of npr-38 shortens the avoidance phase and causes animals to initiate movement quiescence and arouse early. npr-38 functions in the ADL sensory neurons, which express neuropeptides encoded by nlp-50, also required for movement quiescence. npr-38 regulates arousal by acting on the DVA and RIS interneurons. Our work demonstrates that this single GPCR regulates multiple aspects of the stress response by functioning in sensory and sleep interneurons.
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Affiliation(s)
- Emily Le
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA
| | - Teagan McCarthy
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA
| | - Madison Honer
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA
| | - Caroline E Curtin
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA
| | - Jonathan Fingerut
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA
| | - Matthew D Nelson
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA.
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5
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Thapliyal S, Beets I, Glauser DA. Multisite regulation integrates multimodal context in sensory circuits to control persistent behavioral states in C. elegans. Nat Commun 2023; 14:3052. [PMID: 37236963 DOI: 10.1038/s41467-023-38685-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Maintaining or shifting between behavioral states according to context is essential for animals to implement fitness-promoting strategies. How the integration of internal state, past experience and sensory inputs orchestrates persistent multidimensional behavioral changes remains poorly understood. Here, we show that C. elegans integrates environmental temperature and food availability over different timescales to engage in persistent dwelling, scanning, global or glocal search strategies matching thermoregulatory and feeding needs. Transition between states, in each case, involves regulating multiple processes including AFD or FLP tonic sensory neurons activity, neuropeptide expression and downstream circuit responsiveness. State-specific FLP-6 or FLP-5 neuropeptide signaling acts on a distributed set of inhibitory GPCR(s) to promote scanning or glocal search, respectively, bypassing dopamine and glutamate-dependent behavioral state control. Integration of multimodal context via multisite regulation in sensory circuits might represent a conserved regulatory logic for a flexible prioritization on the valence of multiple inputs when operating persistent behavioral state transitions.
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Affiliation(s)
- Saurabh Thapliyal
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland.
| | - Isabel Beets
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, 3000, Leuven, Belgium
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6
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Pu L, Zhao L, Lu Q, Chen C. Hypoxia induces food leaving in C. elegans. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000776. [PMID: 37033703 PMCID: PMC10077061 DOI: 10.17912/micropub.biology.000776] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/05/2023] [Accepted: 03/21/2023] [Indexed: 04/11/2023]
Abstract
Hypoxia alters eating behavior in different animals. In C. elegans , hypoxia induces a strong food leaving response. We found that this behavior was independent of the known O 2 response mechanisms including acute O 2 sensation and HIF-1 signaling of chronic hypoxia response. Mutating egl-3 and egl-21 , encoding the neuropeptide pro-protein convertase and carboxypeptidase, led to defects in hypoxia induced food leaving, suggesting that neuropeptidergic signaling was required for this response. However, we failed to identify any neuropeptide mutants that were severely defective in hypoxia induced food leaving, suggesting that multiple neuropeptides act redundantly to modulate this behavior.
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Affiliation(s)
- Longjun Pu
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Lina Zhao
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Qiongxuan Lu
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Changchun Chen
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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7
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Yoon KH, Indong RA, Lee JI. Making "Sense" of Ecology from a Genetic Perspective: Caenorhabditis elegans, Microbes and Behavior. Metabolites 2022; 12:1084. [PMID: 36355167 PMCID: PMC9697003 DOI: 10.3390/metabo12111084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 12/31/2023] Open
Abstract
Our knowledge of animal and behavior in the natural ecology is based on over a century's worth of valuable field studies. In this post-genome era, however, we recognize that genes are the underpinning of ecological interactions between two organisms. Understanding how genes contribute to animal ecology, which is essentially the intersection of two genomes, is a tremendous challenge. The bacterivorous nematode Caenorhabditis elegans, one of the most well-known genetic animal model experimental systems, experiences a complex microbial world in its natural habitat, providing us with a window into the interplay of genes and molecules that result in an animal-microbial ecology. In this review, we will discuss C. elegans natural ecology, how the worm uses its sensory system to detect the microbes and metabolites that it encounters, and then discuss some of the fascinating ecological dances, including behaviors, that have evolved between the nematode and the microbes in its environment.
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Affiliation(s)
- Kyoung-hye Yoon
- Department of Physiology, Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
| | - Rocel Amor Indong
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 26493, Korea
| | - Jin I. Lee
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju 26493, Korea
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8
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Li Q, Marcu DC, Dear PH, Busch KE. Aerotaxis Assay in Caenorhabditis elegans to Study Behavioral Plasticity. Bio Protoc 2022; 12:e4492. [PMID: 36199707 PMCID: PMC9486685 DOI: 10.21769/bioprotoc.4492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/27/2022] [Accepted: 06/10/2022] [Indexed: 12/29/2022] Open
Abstract
C. elegans shows robust and reproducible behavioral responses to oxygen. Specifically, worms prefer O 2 levels of 5-10% and avoid too high or too low O 2 . Their O 2 preference is not fixed but shows plasticity depending on experience, context, or genetic background. We recently showed that this experience-dependent plasticity declines with age, providing a useful behavioral readout for studying the mechanisms of age-related decline of neural plasticity. Here, we describe a technique to visualize behavioral O 2 preference and its plasticity in C. elegans , by creating spatial gradients of [O 2 ] in a microfluidic polydimethylsiloxane (PDMS) chamber and recording the resulting spatial distribution of the animals.
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Affiliation(s)
- Qiaochu Li
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel-Cosmin Marcu
- Institute for Mind, Brain, and Behaviour, Faculty of Medicine, HMU Health and Medical University, Potsdam, Germany
| | | | - Karl Emanuel Busch
- Institute for Mind, Brain, and Behaviour, Faculty of Medicine, HMU Health and Medical University, Potsdam, Germany
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9
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ROS and cGMP signaling modulate persistent escape from hypoxia in Caenorhabditis elegans. PLoS Biol 2022; 20:e3001684. [PMID: 35727855 PMCID: PMC9249223 DOI: 10.1371/journal.pbio.3001684] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/01/2022] [Accepted: 05/20/2022] [Indexed: 12/02/2022] Open
Abstract
The ability to detect and respond to acute oxygen (O2) shortages is indispensable to aerobic life. The molecular mechanisms and circuits underlying this capacity are poorly understood. Here, we characterize the behavioral responses of feeding Caenorhabditis elegans to approximately 1% O2. Acute hypoxia triggers a bout of turning maneuvers followed by a persistent switch to rapid forward movement as animals seek to avoid and escape hypoxia. While the behavioral responses to 1% O2 closely resemble those evoked by 21% O2, they have distinct molecular and circuit underpinnings. Disrupting phosphodiesterases (PDEs), specific G proteins, or BBSome function inhibits escape from 1% O2 due to increased cGMP signaling. A primary source of cGMP is GCY-28, the ortholog of the atrial natriuretic peptide (ANP) receptor. cGMP activates the protein kinase G EGL-4 and enhances neuroendocrine secretion to inhibit acute responses to 1% O2. Triggering a rise in cGMP optogenetically in multiple neurons, including AIA interneurons, rapidly and reversibly inhibits escape from 1% O2. Ca2+ imaging reveals that a 7% to 1% O2 stimulus evokes a Ca2+ decrease in several neurons. Defects in mitochondrial complex I (MCI) and mitochondrial complex I (MCIII), which lead to persistently high reactive oxygen species (ROS), abrogate acute hypoxia responses. In particular, repressing the expression of isp-1, which encodes the iron sulfur protein of MCIII, inhibits escape from 1% O2 without affecting responses to 21% O2. Both genetic and pharmacological up-regulation of mitochondrial ROS increase cGMP levels, which contribute to the reduced hypoxia responses. Our results implicate ROS and precise regulation of intracellular cGMP in the modulation of acute responses to hypoxia by C. elegans. The ability to detect and respond to acute oxygen shortages is indispensable to aerobic life, but the molecular mechanisms underlying this capacity are poorly understood. This study reveals that high levels of cGMP and reactive oxygen species (ROS) prevent the nematode Caenorhabditis elegans from escaping hypoxia.
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10
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Florman JT, Alkema MJ. Co-transmission of neuropeptides and monoamines choreograph the C. elegans escape response. PLoS Genet 2022; 18:e1010091. [PMID: 35239681 PMCID: PMC8932558 DOI: 10.1371/journal.pgen.1010091] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 03/18/2022] [Accepted: 02/11/2022] [Indexed: 11/19/2022] Open
Abstract
Co-localization and co-transmission of neurotransmitters and neuropeptides is a core property of neural signaling across species. While co-transmission can increase the flexibility of cellular communication, understanding the functional impact on neural dynamics and behavior remains a major challenge. Here we examine the role of neuropeptide/monoamine co-transmission in the orchestration of the C. elegans escape response. The tyraminergic RIM neurons, which coordinate distinct motor programs of the escape response, also co-express the neuropeptide encoding gene flp-18. We find that in response to a mechanical stimulus, flp-18 mutants have defects in locomotory arousal and head bending that facilitate the omega turn. We show that the induction of the escape response leads to the release of FLP-18 neuropeptides. FLP-18 modulates the escape response through the activation of the G-protein coupled receptor NPR-5. FLP-18 increases intracellular calcium levels in neck and body wall muscles to promote body bending. Our results show that FLP-18 and tyramine act in different tissues in both a complementary and antagonistic manner to control distinct motor programs during different phases of the C. elegans flight response. Our study reveals basic principles by which co-transmission of monoamines and neuropeptides orchestrate in arousal and behavior in response to stress.
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Affiliation(s)
- Jeremy T. Florman
- Department of Neurobiology, UMass Chan Medical School, Worcester, Massachusetts, United States of America
| | - Mark J. Alkema
- Department of Neurobiology, UMass Chan Medical School, Worcester, Massachusetts, United States of America
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11
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Valperga G, de Bono M. Impairing one sensory modality enhances another by reconfiguring peptidergic signalling in Caenorhabditis elegans. eLife 2022; 11:68040. [PMID: 35201977 PMCID: PMC8871372 DOI: 10.7554/elife.68040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 02/07/2022] [Indexed: 12/05/2022] Open
Abstract
Animals that lose one sensory modality often show augmented responses to other sensory inputs. The mechanisms underpinning this cross-modal plasticity are poorly understood. We probe such mechanisms by performing a forward genetic screen for mutants with enhanced O2 perception in Caenorhabditis elegans. Multiple mutants exhibiting increased O2 responsiveness concomitantly show defects in other sensory responses. One mutant, qui-1, defective in a conserved NACHT/WD40 protein, abolishes pheromone-evoked Ca2+ responses in the ADL pheromone-sensing neurons. At the same time, ADL responsiveness to pre-synaptic input from O2-sensing neurons is heightened in qui-1, and other sensory defective mutants, resulting in enhanced neurosecretion although not increased Ca2+ responses. Expressing qui-1 selectively in ADL rescues both the qui-1 ADL neurosecretory phenotype and enhanced escape from 21% O2. Profiling ADL neurons in qui-1 mutants highlights extensive changes in gene expression, notably of many neuropeptide receptors. We show that elevated ADL expression of the conserved neuropeptide receptor NPR-22 is necessary for enhanced ADL neurosecretion in qui-1 mutants, and is sufficient to confer increased ADL neurosecretion in control animals. Sensory loss can thus confer cross-modal plasticity by changing the peptidergic connectome.
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Affiliation(s)
- Giulio Valperga
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
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12
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Bergs A, Henss T, Glock C, Nagpal J, Gottschalk A. Microbial Rhodopsin Optogenetic Tools: Application for Analyses of Synaptic Transmission and of Neuronal Network Activity in Behavior. Methods Mol Biol 2022; 2468:89-115. [PMID: 35320562 DOI: 10.1007/978-1-0716-2181-3_6] [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] [Indexed: 06/14/2023]
Abstract
Over the past 15 years, optogenetic methods have revolutionized neuroscientific and cell biological research, also in the nematode Caenorhabditis elegans. In this chapter, we give an update about current optogenetic tools and methods to address neuronal activity and inhibition, as well as second messenger signaling, based on microbial rhodopsins. We address channelrhodopsins and variants thereof, which conduct cations or anions, for depolarization and hyperpolarization of the membrane potential. Also, we cover ion pumping rhodopsins, like halorhodopsin, Mac, and Arch. A recent addition to rhodopsin-based optogenetics is voltage imaging tools that allow fluorescent readout of membrane voltage (directly, via fluorescence of the rhodopsin chromophore retinal, or indirectly, via electrochromic FRET). Last, we report on a new addition to the optogenetic toolbox, which is rhodopsin guanylyl cyclases, as well as mutated variants with specificity for cyclic AMP. These can be used to regulate intracellular levels of cGMP and cAMP, which are important second messengers in sensory and other neurons. We further show how they can be combined with cyclic nucleotide-gated channels in two-component optogenetics, for depolarization or hyperpolarization of membrane potential. For all tools, we present protocols for straightforward experimentation to address neuronal activation and inhibition, particularly at the neuromuscular junction, and for combined optogenetic actuation and Ca2+ imaging. We also provide protocols for usage of rhodopsin guanylyl and adenylyl cyclases. Finally, we list a number of points to consider when designing and conducting rhodopsin-based optogenetic experiments.
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Affiliation(s)
- Amelie Bergs
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Thilo Henss
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Caspar Glock
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
- Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Jatin Nagpal
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany.
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13
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Ippolito D, Thapliyal S, Glauser DA. Ca 2+/CaM binding to CaMKI promotes IMA-3 importin binding and nuclear translocation in sensory neurons to control behavioral adaptation. eLife 2021; 10:71443. [PMID: 34766550 PMCID: PMC8635976 DOI: 10.7554/elife.71443] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/11/2021] [Indexed: 12/29/2022] Open
Abstract
Sensory and behavioral plasticity are essential for animals to thrive in changing environments. As key effectors of intracellular calcium signaling, Ca2+/calmodulin-dependent protein kinases (CaMKs) can bridge neural activation with the many regulatory processes needed to orchestrate sensory adaptation, including by relaying signals to the nucleus. Here, we elucidate the molecular mechanism controlling the cell activation-dependent nuclear translocation of CMK-1, the Caenorhabditis elegans ortholog of mammalian CaMKI/IV, in thermosensory neurons in vivo. We show that an intracellular Ca2+ concentration elevation is necessary and sufficient to favor CMK-1 nuclear import. The binding of Ca2+/CaM to CMK-1 increases its affinity for IMA-3 importin, causing a redistribution with a relatively slow kinetics, matching the timescale of sensory adaptation. Furthermore, we show that this mechanism enables the encoding of opposite nuclear signals in neuron types with opposite calcium-responses and that it is essential for experience-dependent behavioral plasticity and gene transcription control in vivo. Since CaMKI/IV are conserved regulators of adaptable behaviors, similar mechanisms could exist in other organisms and for other sensory modalities.
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Affiliation(s)
- Domenica Ippolito
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Saurabh Thapliyal
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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14
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Vuong-Brender TT, Flynn S, Vallis Y, de Bono M. Neuronal calmodulin levels are controlled by CAMTA transcription factors. eLife 2021; 10:68238. [PMID: 34499028 PMCID: PMC8428840 DOI: 10.7554/elife.68238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/28/2021] [Indexed: 01/18/2023] Open
Abstract
The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior.
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Affiliation(s)
- Thanh Thi Vuong-Brender
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Sean Flynn
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Yvonne Vallis
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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15
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Koopman M, Janssen L, Nollen EAA. An economical and highly adaptable optogenetics system for individual and population-level manipulation of Caenorhabditis elegans. BMC Biol 2021; 19:170. [PMID: 34429103 PMCID: PMC8386059 DOI: 10.1186/s12915-021-01085-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/06/2021] [Indexed: 11/10/2022] Open
Abstract
Background Optogenetics allows the experimental manipulation of excitable cells by a light stimulus without the need for technically challenging and invasive procedures. The high degree of spatial, temporal, and intensity control that can be achieved with a light stimulus, combined with cell type-specific expression of light-sensitive ion channels, enables highly specific and precise stimulation of excitable cells. Optogenetic tools have therefore revolutionized the study of neuronal circuits in a number of models, including Caenorhabditis elegans. Despite the existence of several optogenetic systems that allow spatial and temporal photoactivation of light-sensitive actuators in C. elegans, their high costs and low flexibility have limited wide access to optogenetics. Here, we developed an inexpensive, easy-to-build, modular, and adjustable optogenetics device for use on different microscopes and worm trackers, which we called the OptoArm. Results The OptoArm allows for single- and multiple-worm illumination and is adaptable in terms of light intensity, lighting profiles, and light color. We demonstrate OptoArm’s power in a population-based multi-parameter study on the contributions of motor circuit cells to age-related motility decline. We found that individual components of the neuromuscular system display different rates of age-dependent deterioration. The functional decline of cholinergic neurons mirrors motor decline, while GABAergic neurons and muscle cells are relatively age-resilient, suggesting that rate-limiting cells exist and determine neuronal circuit ageing. Conclusion We have assembled an economical, reliable, and highly adaptable optogenetics system which can be deployed to address diverse biological questions. We provide a detailed description of the construction as well as technical and biological validation of our set-up. Importantly, use of the OptoArm is not limited to C. elegans and may benefit studies in multiple model organisms, making optogenetics more accessible to the broader research community. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01085-2.
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Affiliation(s)
- M Koopman
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - L Janssen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - E A A Nollen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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16
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Emmons SW, Yemini E, Zimmer M. Methods for analyzing neuronal structure and activity in Caenorhabditis elegans. Genetics 2021; 218:6303616. [PMID: 34151952 DOI: 10.1093/genetics/iyab072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
The model research animal Caenorhabditis elegans has unique properties making it particularly advantageous for studies of the nervous system. The nervous system is composed of a stereotyped complement of neurons connected in a consistent manner. Here, we describe methods for studying nervous system structure and function. The transparency of the animal makes it possible to visualize and identify neurons in living animals with fluorescent probes. These methods have been recently enhanced for the efficient use of neuron-specific reporter genes. Because of its simple structure, for a number of years, C. elegans has been at the forefront of connectomic studies defining synaptic connectivity by electron microscopy. This field is burgeoning with new, more powerful techniques, and recommended up-to-date methods are here described that encourage the possibility of new work in C. elegans. Fluorescent probes for single synapses and synaptic connections have allowed verification of the EM reconstructions and for experimental approaches to synapse formation. Advances in microscopy and in fluorescent reporters sensitive to Ca2+ levels have opened the way to observing activity within single neurons across the entire nervous system.
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Affiliation(s)
- Scott W Emmons
- Department of Genetics and Dominick Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 1041, USA
| | - Eviatar Yemini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria and.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna 1030, Austria
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17
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de Lima TM, Nery LEM, Maciel FE, Ngo-Vu H, Kozma MT, Derby CD. Oxygen sensing in crustaceans: functions and mechanisms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:1-15. [PMID: 33392718 DOI: 10.1007/s00359-020-01457-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022]
Abstract
Animals that live in changing environments need to adjust their metabolism to maintain body functions, and sensing these changing conditions is essential for mediating the short- and long-term physiological and behavioral responses that make these adjustments. Previous research on nematodes and insects facing changing oxygen levels has shown that these animals rapidly respond using atypical soluble guanylyl cyclases (sGCs) as oxygen sensors connected to downstream cGMP pathways, and they respond more slowly using hypoxia-inducible transcription factors (HIFs) that are further modulated by oxygen-sensing prolyl hydroxylases (PHs). Crustaceans are known to respond in different ways to hypoxia, but the mechanisms responsible for sensing oxygen levels are more poorly understood than in nematodes and insects. Our paper reviews the functions of and mechanisms underlying oxygen sensing in crustaceans. Furthermore, using the oxygen sensing abilities of nematodes and insects as guides in analyzing available crustacean transcriptomes, we identified orthologues of atypical sGCs, HIFs, and PHs in crustaceans, including in their chemosensory organs and neurons. These molecules include atypical sGCs activated by hypoxia (Gyc-88E/GCY-31 and Gyc-89D/GCY-33) but not those activated by hyperoxia (GCY-35, GCY-36), as well as orthologues of HIF-α, HIF-β, and PH. We offer possible directions for future research on oxygen sensing by crustaceans.
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Affiliation(s)
- Tábata Martins de Lima
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil.
| | - Luiz Eduardo Maia Nery
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil
| | - Fábio Everton Maciel
- Programa de Pós-Graduação Em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, 96201-300, Brazil
| | - Hanh Ngo-Vu
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Mihika T Kozma
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA.,Department of Biology, Colorado State University, Ft. Collins, CO, USA
| | - Charles D Derby
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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18
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Rossillo M, Ringstad N. Development of specialized sensory neurons engages a nuclear receptor required for functional plasticity. Genes Dev 2020; 34:1666-1679. [PMID: 33184226 PMCID: PMC7706712 DOI: 10.1101/gad.342212.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/30/2020] [Indexed: 12/12/2022]
Abstract
In this study, Rossillo and Ringstad sought to determine mechanisms that support the physiology and plasticity of BAG neurons, which are specialized neurons that sense the respiratory gas carbon dioxide (CO2) and, in a context-dependent manner, switch from mediating avoidance of CO2 to supporting CO2 attraction in C. elegans. They used tandem ChIP-seq and cell targeted RNA-seq to identify gene targets of the transcription factor ETS-5, which is required for BAG development, and their functional screen of ETS-5 targets revealed that NHR-6, the sole C. elegans NR4A-type nuclear receptor, is required for BAG-mediated avoidance of CO2 and regulates expression of a subset of BAG-specific genes. During development, the nervous system generates neurons that serve highly specialized roles and, accordingly, possess unique functional attributes. The chemosensory BAG neurons of C. elegans are striking exemplars of this. BAGs sense the respiratory gas carbon dioxide (CO2) and, in a context-dependent manner, switch from mediating avoidance of CO2 to supporting CO2 attraction. To determine mechanisms that support the physiology and plasticity of BAG neurons, we used tandem ChIP-seq and cell targeted RNA-seq to identify gene targets of the transcription factor ETS-5, which is required for BAG development. A functional screen of ETS-5 targets revealed that NHR-6, the sole C. elegans NR4A-type nuclear receptor, is required for BAG-mediated avoidance of CO2 and regulates expression of a subset of BAG-specific genes. Unlike ets-5 mutants, which are defective for both attraction to and avoidance of CO2, nhr-6 mutants are fully competent for attraction. These data indicate that the remarkable ability of BAGs to adaptively assign positive or negative valence to a chemosensory stimulus requires a gene-regulatory program supported by an evolutionarily conserved type of nuclear receptor. We suggest that NHR-6 might be an example of a developmental mechanism for modular encoding of functional plasticity in the nervous system.
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Affiliation(s)
- Mary Rossillo
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
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19
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Li Q, Marcu DC, Palazzo O, Turner F, King D, Spires-Jones TL, Stefan MI, Busch KE. High neural activity accelerates the decline of cognitive plasticity with age in Caenorhabditis elegans. eLife 2020; 9:59711. [PMID: 33228848 PMCID: PMC7685709 DOI: 10.7554/elife.59711] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022] Open
Abstract
The ability to learn progressively declines with age. Neural hyperactivity has been implicated in impairing cognitive plasticity with age, but the molecular mechanisms remain elusive. Here, we show that chronic excitation of the Caenorhabditis elegans O2-sensing neurons during ageing causes a rapid decline of experience-dependent plasticity in response to environmental O2 concentration, whereas sustaining lower activity of O2-sensing neurons retains plasticity with age. We demonstrate that neural activity alters the ageing trajectory in the transcriptome of O2-sensing neurons, and our data suggest that high-activity neurons redirect resources from maintaining plasticity to sustaining continuous firing. Sustaining plasticity with age requires the K+-dependent Na+/Ca2+ (NCKX) exchanger, whereas the decline of plasticity with age in high-activity neurons acts through calmodulin and the scaffold protein Kidins220. Our findings demonstrate directly that the activity of neurons alters neuronal homeostasis to govern the age-related decline of neural plasticity and throw light on the mechanisms involved.
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Affiliation(s)
- Qiaochu Li
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel-Cosmin Marcu
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ottavia Palazzo
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Frances Turner
- Edinburgh Genomics (Genome Science), Ashworth Laboratories, The University of Edinburgh, Edinburgh, United Kingdom
| | - Declan King
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Melanie I Stefan
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,ZJU-UoE Institute, Zhejiang University, Haining, China
| | - Karl Emanuel Busch
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Edinburgh, United Kingdom
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20
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Abstract
For the first 25 years after the landmark 1974 paper that launched the field, most C. elegans biologists were content to think of their subjects as solitary creatures. C. elegans presented no shortage of fascinating biological problems, but some of the features that led Brenner to settle on this species-in particular, its free-living, self-fertilizing lifestyle-also seemed to reduce its potential for interesting social behavior. That perspective soon changed, with the last two decades bringing remarkable progress in identifying and understanding the complex interactions between worms. The growing appreciation that C. elegans behavior can only be meaningfully understood in the context of its ecology and evolution ensures that the coming years will see similarly exciting progress.
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Affiliation(s)
- Douglas S Portman
- Departments of Biomedical Genetics, Neuroscience, and Biology, Del Monte Institute for Neuroscience, University of Rochester, Rochester, NY, USA
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21
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Molina-García L, Lloret-Fernández C, Cook SJ, Kim B, Bonnington RC, Sammut M, O'Shea JM, Gilbert SPR, Elliott DJ, Hall DH, Emmons SW, Barrios A, Poole RJ. Direct glia-to-neuron transdifferentiation gives rise to a pair of male-specific neurons that ensure nimble male mating. eLife 2020; 9:e48361. [PMID: 33138916 PMCID: PMC7609048 DOI: 10.7554/elife.48361] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/02/2020] [Indexed: 12/20/2022] Open
Abstract
Sexually dimorphic behaviours require underlying differences in the nervous system between males and females. The extent to which nervous systems are sexually dimorphic and the cellular and molecular mechanisms that regulate these differences are only beginning to be understood. We reveal here a novel mechanism by which male-specific neurons are generated in Caenorhabditis elegans through the direct transdifferentiation of sex-shared glial cells. This glia-to-neuron cell fate switch occurs during male sexual maturation under the cell-autonomous control of the sex-determination pathway. We show that the neurons generated are cholinergic, peptidergic, and ciliated putative proprioceptors which integrate into male-specific circuits for copulation. These neurons ensure coordinated backward movement along the mate's body during mating. One step of the mating sequence regulated by these neurons is an alternative readjustment movement performed when intromission becomes difficult to achieve. Our findings reveal programmed transdifferentiation as a developmental mechanism underlying flexibility in innate behaviour.
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Affiliation(s)
- Laura Molina-García
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Carla Lloret-Fernández
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Steven J Cook
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineNew YorkUnited States
| | - Byunghyuk Kim
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Rachel C Bonnington
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Michele Sammut
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Jack M O'Shea
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Sophie PR Gilbert
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - David J Elliott
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - David H Hall
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Scott W Emmons
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineNew YorkUnited States
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Arantza Barrios
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Richard J Poole
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
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22
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Kazatskaya A, Yuan L, Amin-Wetzel N, Philbrook A, de Bono M, Sengupta P. The URX oxygen-sensing neurons in C. elegans are ciliated. MICROPUBLICATION BIOLOGY 2020; 2020:10.17912/micropub.biology.000303. [PMID: 33005885 PMCID: PMC7520127 DOI: 10.17912/micropub.biology.000303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022]
Affiliation(s)
| | - Lisa Yuan
- Brandeis University, Waltham, MA 02454
| | - Niko Amin-Wetzel
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | - Mario de Bono
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
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23
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Lorenzo R, Onizuka M, Defrance M, Laurent P. Combining single-cell RNA-sequencing with a molecular atlas unveils new markers for Caenorhabditis elegans neuron classes. Nucleic Acids Res 2020; 48:7119-7134. [PMID: 32542321 PMCID: PMC7367206 DOI: 10.1093/nar/gkaa486] [Citation(s) in RCA: 16] [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: 11/08/2019] [Revised: 05/11/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022] Open
Abstract
Single-cell RNA-sequencing (scRNA-seq) of the Caenorhabditis elegans nervous system offers the unique opportunity to obtain a partial expression profile for each neuron within a known connectome. Building on recent scRNA-seq data and on a molecular atlas describing the expression pattern of ∼800 genes at the single cell resolution, we designed an iterative clustering analysis aiming to match each cell-cluster to the ∼100 anatomically defined neuron classes of C. elegans. This heuristic approach successfully assigned 97 of the 118 neuron classes to a cluster. Sixty two clusters were assigned to a single neuron class and 15 clusters grouped neuron classes sharing close molecular signatures. Pseudotime analysis revealed a maturation process occurring in some neurons (e.g. PDA) during the L2 stage. Based on the molecular profiles of all identified neurons, we predicted cell fate regulators and experimentally validated unc-86 for the normal differentiation of RMG neurons. Furthermore, we observed that different classes of genes functionally diversify sensory neurons, interneurons and motorneurons. Finally, we designed 15 new neuron class-specific promoters validated in vivo. Amongst them, 10 represent the only specific promoter reported to this day, expanding the list of neurons amenable to genetic manipulations.
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Affiliation(s)
- Ramiro Lorenzo
- Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium
- Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET-CICPBA-UNCPBA, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro (FCV-UNCPBA), Tandil, Argentina
| | - Michiho Onizuka
- Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Matthieu Defrance
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles, Brussels, Belgium
| | - Patrick Laurent
- Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium
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24
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Demir E, Yaman YI, Basaran M, Kocabas A. Dynamics of pattern formation and emergence of swarming in Caenorhabditis elegans. eLife 2020; 9:52781. [PMID: 32250243 PMCID: PMC7202895 DOI: 10.7554/elife.52781] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 04/05/2020] [Indexed: 01/10/2023] Open
Abstract
Many animals collectively form complex patterns to tackle environmental difficulties. Several biological and physical factors, such as animal motility, population densities, and chemical cues, play significant roles in this process. However, very little is known about how sensory information interplays with these factors and controls the dynamics of pattern formation. Here, we study the direct relation between oxygen sensing, pattern formation, and emergence of swarming in active Caenorhabditis elegans aggregates. We find that when thousands of animals gather on food, bacteria-mediated decrease in oxygen level slows down the animals and triggers motility-induced phase separation. Three coupled factors—bacterial accumulation, aerotaxis, and population density—act together and control the entire dynamics. Furthermore, we find that biofilm-forming bacterial lawns including Bacillus subtilis and Pseudomonas aeruginosa strongly alter the collective dynamics due to the limited diffusibility of bacteria. Additionally, our theoretical model captures behavioral differences resulting from genetic variations and oxygen sensitivity.
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Affiliation(s)
- Esin Demir
- Bio-Medical Sciences and Engineering Program, Koç University, Sarıyer, Istanbul, Turkey
| | - Y Ilker Yaman
- Department of Physics, Koç University, Sarıyer, Istanbul, Turkey
| | - Mustafa Basaran
- Bio-Medical Sciences and Engineering Program, Koç University, Sarıyer, Istanbul, Turkey
| | - Askin Kocabas
- Bio-Medical Sciences and Engineering Program, Koç University, Sarıyer, Istanbul, Turkey.,Department of Physics, Koç University, Sarıyer, Istanbul, Turkey.,Koç University Surface Science and Technology Center, Koç University, Sarıyer, Istanbul, Turkey.,Koç University Research Center for Translational Medicine, Koç University, Sarıyer, Istanbul, Turkey
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25
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Long-term activity drives dendritic branch elaboration of a C. elegans sensory neuron. Dev Biol 2020; 461:66-74. [PMID: 31945343 PMCID: PMC7170766 DOI: 10.1016/j.ydbio.2020.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Neuronal activity often leads to alterations in gene expression and cellular architecture. The nematode Caenorhabditis elegans, owing to its compact translucent nervous system, is a powerful system in which to study conserved aspects of the development and plasticity of neuronal morphology. Here we focus on one pair of sensory neurons, termed URX, which the worm uses to sense and avoid high levels of environmental oxygen. Previous studies have reported that the URX neuron pair has variable branched endings at its dendritic sensory tip. By controlling oxygen levels and analyzing mutants, we found that these microtubule-rich branched endings grow over time as a consequence of neuronal activity in adulthood. We also find that the growth of these branches correlates with an increase in cellular sensitivity to particular ranges of oxygen that is observable in the behavior of older worms. Given the strengths of C. elegans as a model organism, URX may serve as a potent system for uncovering genes and mechanisms involved in activity-dependent morphological changes in neurons and possible adaptive changes in the aging nervous system. The dendritic tip of an oxygen-sensing neuron grows elaborate microtubule-rich processes in adult C. elegans. Dendritic tip elaboration depends on the long-term activity of the neuron and calcium. The elaboration correlates with increased sensitivity of the neuron to certain ranges of oxygen as well as higher avoidance of oxygen during bordering behavior. The dendritic tip changes may reflect adaptive changes in physiology and behavior during adulthood.
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26
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Saro G, Lia AS, Thapliyal S, Marques F, Busch KE, Glauser DA. Specific Ion Channels Control Sensory Gain, Sensitivity, and Kinetics in a Tonic Thermonociceptor. Cell Rep 2020; 30:397-408.e4. [DOI: 10.1016/j.celrep.2019.12.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/17/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022] Open
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27
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Marques F, Saro G, Lia AS, Poole RJ, Falquet L, Glauser DA. Identification of avoidance genes through neural pathway-specific forward optogenetics. PLoS Genet 2019; 15:e1008509. [PMID: 31891575 PMCID: PMC6938339 DOI: 10.1371/journal.pgen.1008509] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/05/2019] [Indexed: 11/19/2022] Open
Abstract
Understanding how the nervous system bridges sensation and behavior requires the elucidation of complex neural and molecular networks. Forward genetic approaches, such as screens conducted in C. elegans, have successfully identified genes required to process natural sensory stimuli. However, functional redundancy within the underlying neural circuits, which are often organized with multiple parallel neural pathways, limits our ability to identify 'neural pathway-specific genes', i.e. genes that are essential for the function of some, but not all of these redundant neural pathways. To overcome this limitation, we developed a 'forward optogenetics' screening strategy in which natural stimuli are initially replaced by the selective optogenetic activation of a specific neural pathway. We used this strategy to address the function of the polymodal FLP nociceptors mediating avoidance of noxious thermal and mechanical stimuli. According to our expectations, we identified both mutations in 'general' avoidance genes that broadly impact avoidance responses to a variety of natural noxious stimuli (unc-4, unc-83, and eat-4) and mutations that produce a narrower impact, more restricted to the FLP pathway (syd-2, unc-14 and unc-68). Through a detailed follow-up analysis, we further showed that the Ryanodine receptor UNC-68 acts cell-autonomously in FLP to adjust heat-evoked calcium signals and aversive behaviors. As a whole, our work (i) reveals the importance of properly regulated ER calcium release for FLP function, (ii) provides new entry points for new nociception research and (iii) demonstrates the utility of our forward optogenetic strategy, which can easily be transposed to analyze other neural pathways.
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Affiliation(s)
- Filipe Marques
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Gabriella Saro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Andrei-Stefan Lia
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Richard J. Poole
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Swiss Institute of Bioinformatics, Fribourg, Switzerland
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28
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Bouagnon AD, Lin L, Srivastava S, Liu CC, Panda O, Schroeder FC, Srinivasan S, Ashrafi K. Intestinal peroxisomal fatty acid β-oxidation regulates neural serotonin signaling through a feedback mechanism. PLoS Biol 2019; 17:e3000242. [PMID: 31805041 PMCID: PMC6917301 DOI: 10.1371/journal.pbio.3000242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 12/17/2019] [Accepted: 11/15/2019] [Indexed: 02/02/2023] Open
Abstract
The ability to coordinate behavioral responses with metabolic status is fundamental to the maintenance of energy homeostasis. In numerous species including Caenorhabditis elegans and mammals, neural serotonin signaling regulates a range of food-related behaviors. However, the mechanisms that integrate metabolic information with serotonergic circuits are poorly characterized. Here, we identify metabolic, molecular, and cellular components of a circuit that links peripheral metabolic state to serotonin-regulated behaviors in C. elegans. We find that blocking the entry of fatty acyl coenzyme As (CoAs) into peroxisomal β-oxidation in the intestine blunts the effects of neural serotonin signaling on feeding and egg-laying behaviors. Comparative genomics and metabolomics revealed that interfering with intestinal peroxisomal β-oxidation results in a modest global transcriptional change but significant changes to the metabolome, including a large number of changes in ascaroside and phospholipid species, some of which affect feeding behavior. We also identify body cavity neurons and an ether-a-go-go (EAG)-related potassium channel that functions in these neurons as key cellular components of the circuitry linking peripheral metabolic signals to regulation of neural serotonin signaling. These data raise the possibility that the effects of serotonin on satiety may have their origins in feedback, homeostatic metabolic responses from the periphery.
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Affiliation(s)
- Aude D. Bouagnon
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Lin Lin
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Shubhi Srivastava
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Chung-Chih Liu
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Oishika Panda
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Frank C. Schroeder
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Supriya Srinivasan
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Kaveh Ashrafi
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
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29
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Robinson KJ, Bosch OJ, Levkowitz G, Busch KE, Jarman AP, Ludwig M. Social creatures: Model animal systems for studying the neuroendocrine mechanisms of social behaviour. J Neuroendocrinol 2019; 31:e12807. [PMID: 31679160 PMCID: PMC6916380 DOI: 10.1111/jne.12807] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/11/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022]
Abstract
The interaction of animals with conspecifics, termed social behaviour, has a major impact on the survival of many vertebrate species. Neuropeptide hormones modulate the underlying physiology that governs social interactions, and many findings concerning the neuroendocrine mechanisms of social behaviours have been extrapolated from animal models to humans. Neurones expressing neuropeptides show similar distribution patterns within the hypothalamic nucleus, even when evolutionarily distant species are compared. During evolution, hypothalamic neuropeptides and releasing hormones have retained not only their structures, but also their biological functions, including their effects on behaviour. Here, we review the current understanding of the mechanisms of social behaviours in several classes of animals, such as worms, insects and fish, as well as laboratory, wild and domesticated mammals.
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Affiliation(s)
- Kelly J. Robinson
- Sea Mammal Research UnitScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | - Oliver J. Bosch
- Department of Behavioural and Molecular NeurobiologyUniversity of RegensburgRegensburgGermany
| | - Gil Levkowitz
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | | | - Andrew P. Jarman
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
| | - Mike Ludwig
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
- Centre for NeuroendocrinologyDepartment of ImmunologyUniversity of PretoriaPretoriaSouth Africa
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30
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Beets I, Zhang G, Fenk LA, Chen C, Nelson GM, Félix MA, de Bono M. Natural Variation in a Dendritic Scaffold Protein Remodels Experience-Dependent Plasticity by Altering Neuropeptide Expression. Neuron 2019; 105:106-121.e10. [PMID: 31757604 PMCID: PMC6953435 DOI: 10.1016/j.neuron.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 08/18/2019] [Accepted: 09/28/2019] [Indexed: 12/13/2022]
Abstract
The extent to which behavior is shaped by experience varies between individuals. Genetic differences contribute to this variation, but the neural mechanisms are not understood. Here, we dissect natural variation in the behavioral flexibility of two Caenorhabditis elegans wild strains. In one strain, a memory of exposure to 21% O2 suppresses CO2-evoked locomotory arousal; in the other, CO2 evokes arousal regardless of previous O2 experience. We map that variation to a polymorphic dendritic scaffold protein, ARCP-1, expressed in sensory neurons. ARCP-1 binds the Ca2+-dependent phosphodiesterase PDE-1 and co-localizes PDE-1 with molecular sensors for CO2 at dendritic ends. Reducing ARCP-1 or PDE-1 activity promotes CO2 escape by altering neuropeptide expression in the BAG CO2 sensors. Variation in ARCP-1 alters behavioral plasticity in multiple paradigms. Our findings are reminiscent of genetic accommodation, an evolutionary process by which phenotypic flexibility in response to environmental variation is reset by genetic change. Behavioral flexibility varies across Caenorhabditis and C. elegans wild isolates A natural polymorphism in ARCP-1 underpins inter-individual variation in plasticity ARCP-1 is a dendritic scaffold protein localizing cGMP signaling machinery to cilia Disrupting ARCP-1 alters behavioral plasticity by changing neuropeptide expression
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Affiliation(s)
- Isabel Beets
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Gaotian Zhang
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France
| | - Lorenz A Fenk
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Changchun Chen
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Geoffrey M Nelson
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris 75005, France.
| | - Mario de Bono
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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31
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Activity-Dependent Regulation of the Proapoptotic BH3-Only Gene egl-1 in a Living Neuron Pair in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2019; 9:3703-3714. [PMID: 31519744 PMCID: PMC6829140 DOI: 10.1534/g3.119.400654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The BH3-only family of proteins is key for initiating apoptosis in a variety of contexts, and may also contribute to non-apoptotic cellular processes. Historically, the nematode Caenorhabditis elegans has provided a powerful system for studying and identifying conserved regulators of BH3-only proteins. In C. elegans, the BH3-only protein egl-1 is expressed during development to cell-autonomously trigger most developmental cell deaths. Here we provide evidence that egl-1 is also transcribed after development in the sensory neuron pair URX without inducing apoptosis. We used genetic screening and epistasis analysis to determine that its transcription is regulated in URX by neuronal activity and/or in parallel by orthologs of Protein Kinase G and the Salt-Inducible Kinase family. Because several BH3-only family proteins are also expressed in the adult nervous system of mammals, we suggest that studying egl-1 expression in URX may shed light on mechanisms that regulate conserved family members in higher organisms.
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32
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Romero-Afrima L, Zelmanovich V, Abergel Z, Zuckerman B, Shaked M, Abergel R, Livshits L, Smith Y, Gross E. Ferritin is regulated by a neuro-intestinal axis in the nematode Caenorhabditis elegans. Redox Biol 2019; 28:101359. [PMID: 31677552 PMCID: PMC6920132 DOI: 10.1016/j.redox.2019.101359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/17/2019] [Accepted: 10/21/2019] [Indexed: 01/24/2023] Open
Abstract
Iron is vital for the life of most organisms. However, when dysregulated, iron can catalyze the formation of oxygen (O2) radicals that can destroy any biological molecule and thus lead to oxidative injury and death. Therefore, iron metabolism must be tightly regulated at all times, as well as coordinated with the metabolism of O2. However, how is this achieved at the whole animal level is not well understood. Here, we explore this question using the nematode Caenorhabditis elegans. Exposure of worms to O2 starvation conditions (i.e. hypoxia) induces a major upregulation in levels of the conserved iron-cage protein ferritin 1 (ftn-1) in the intestine, while exposure to 21% O2 decreases ftn-1 level. This O2-dependent inhibition is mediated by O2-sensing neurons that communicate with the intestine through neurotransmitter and neuropeptide signalling, and requires the activity of hydroxylated HIF-1. By contrast, the induction of ftn-1 in hypoxia appears to be HIF-1-independent. This upregulation provides protection against Pseudomonas aeruginosa bacteria and oxidative injury. Taken together, our studies uncover a neuro-intestine axis that coordinates O2 and iron responses at the whole animal level. The expression of ferritin 1 (ftn-1) is tightly regulated by O2 tension. O2-sensing neurons inhibit the expression of ftn-1 in the intestine at 21% O2. Hydroxylated–HIF–1 inhibits the expression of ftn-1 at 21% O2. ftn-1 is important for protecting against Pseudomonas aeruginosa bacteria.
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Affiliation(s)
- Leonor Romero-Afrima
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Veronica Zelmanovich
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Zohar Abergel
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Binyamin Zuckerman
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Maayan Shaked
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Rachel Abergel
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Leonid Livshits
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Yoav Smith
- Genomic Data Analysis Unit, The Hebrew University - Hadassah Medical School, The Hebrew University of Jerusalem, 91120, Jerusalem, Israel
| | - Einav Gross
- Dept. of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel.
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33
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Ding SS, Schumacher LJ, Javer AE, Endres RG, Brown AEX. Shared behavioral mechanisms underlie C. elegans aggregation and swarming. eLife 2019; 8:e43318. [PMID: 31021320 PMCID: PMC6522220 DOI: 10.7554/elife.43318] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 04/19/2019] [Indexed: 11/13/2022] Open
Abstract
In complex biological systems, simple individual-level behavioral rules can give rise to emergent group-level behavior. While collective behavior has been well studied in cells and larger organisms, the mesoscopic scale is less understood, as it is unclear which sensory inputs and physical processes matter a priori. Here, we investigate collective feeding in the roundworm C. elegans at this intermediate scale, using quantitative phenotyping and agent-based modeling to identify behavioral rules underlying both aggregation and swarming-a dynamic phenotype only observed at longer timescales. Using fluorescence multi-worm tracking, we quantify aggregation in terms of individual dynamics and population-level statistics. Then we use agent-based simulations and approximate Bayesian inference to identify three key behavioral rules for aggregation: cluster-edge reversals, a density-dependent switch between crawling speeds, and taxis towards neighboring worms. Our simulations suggest that swarming is simply driven by local food depletion but otherwise employs the same behavioral mechanisms as the initial aggregation.
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Affiliation(s)
- Siyu Serena Ding
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Linus J Schumacher
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
- MRC Centre for Regenerative MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Avelino E Javer
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Robert G Endres
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - André EX Brown
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
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34
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Parfenov VA, Ostroumova OD, Ostroumova TM, Kochetkov AI, Fateeva VV, Khacheva KK, Khakimova GR, Epstein OI. Vascular cognitive impairment: pathophysiological mechanisms, insights into structural basis, and perspectives in specific treatments. Neuropsychiatr Dis Treat 2019; 15:1381-1402. [PMID: 31190841 PMCID: PMC6535085 DOI: 10.2147/ndt.s197032] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/14/2019] [Indexed: 01/19/2023] Open
Abstract
Vascular cognitive impairment (VCI) and vascular dementia are the most common forms of cognitive disorder associated with cerebrovascular disease and related to increased morbidity and mortality among the older population. Growing evidence suggests the contribution of blood-pressure variability, cardiac arrhythmia, hyperactivation of the renin-angiotensin-aldosterone system, endothelial dysfunction, vascular remodeling and stiffness, different angiopathies, neural tissue homeostasis, and systemic metabolic disorders to the pathophysiology of VCI. In this review, we focus on factors contributing to cerebrovascular disease, neurovascular unit alterations, and novel approaches to cognitive improvement in patients with cognitive decline. One of the important factors associated with the neuronal causes of VCI is the S100B protein, which can affect the expression of cytokines in the brain, support homeostasis, and regulate processes of differentiation, repair, and apoptosis of the nervous tissue. Since the pathological basis of VCI is complex and diverse, treatment affecting the mechanisms of cognitive disorders should be developed. The prospective role of a novel complex drug consisting of released-active antibodies to S100 and to endothelial NO synthase in VCI treatment is highlighted.
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Affiliation(s)
- Vladimir A Parfenov
- Department of Neurology, Federal State Autonomous Educational Institution of Higher Education, I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russian Federation
| | - Olga D Ostroumova
- Laboratory of Clinical Pharmacology and therapy, Federal State Budgetary Educational Institution of Higher Education "N.I. Pirogov Russian National Research Medical University" of the Ministry of Health of the Russian Federation, Russian Clinical and Research Center of Gerontology, Moscow, Russia.,Department of Clinical Pharmacology, Internal Medicine and Propaedeutics I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Tatiana M Ostroumova
- Department of Neurology, Federal State Autonomous Educational Institution of Higher Education, I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russian Federation
| | - Alexey I Kochetkov
- Laboratory of Clinical Pharmacology and therapy, Federal State Budgetary Educational Institution of Higher Education "N.I. Pirogov Russian National Research Medical University" of the Ministry of Health of the Russian Federation, Russian Clinical and Research Center of Gerontology, Moscow, Russia
| | - Victoria V Fateeva
- Medical Information Department, OOO NPF Materia Medica Holding, Moscow, Russian Federation
| | - Kristina K Khacheva
- Medical Information Department, OOO NPF Materia Medica Holding, Moscow, Russian Federation
| | - Gulnara R Khakimova
- Research and Analytical Division of Scientific Research and Development Department, Moscow, Russian Federation
| | - Oleg I Epstein
- Laboratory of Physiologicaly Active Substances, Department of Molecular and Cellular Pathophysiology, Research Institute of General Pathology and Pathophysiology, Moscow, Russian Federation
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35
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Lee JB, Yonar A, Hallacy T, Shen CH, Milloz J, Srinivasan J, Kocabas A, Ramanathan S. A compressed sensing framework for efficient dissection of neural circuits. Nat Methods 2018; 16:126-133. [PMID: 30573831 PMCID: PMC6335042 DOI: 10.1038/s41592-018-0233-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 10/31/2018] [Indexed: 01/12/2023]
Abstract
A fundamental question in neuroscience is how neural networks generate behavior. The lack of genetic tools and unique promoters to functionally manipulate specific neuronal subtypes makes it challenging to determine the roles of individual subtypes in behavior. We describe a compressed sensing-based framework in combination with non-specific genetic tools to infer candidate neurons controlling behaviors with fewer measurements than previously thought possible. We tested this framework by inferring interneuron subtypes regulating the speed of locomotion of the nematode Caenorhabditis elegans. We developed a real-time stabilization microscope for accurate long-term, high-magnification imaging and targeted perturbation of neural activity in freely moving animals to validate our inferences. We show that a circuit of three interconnected interneuron subtypes, RMG, AVB and SIA control different aspects of locomotion speed as the animal navigates its environment. Our work suggests that compressed sensing approaches can be used to identify key nodes in complex biological networks.
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Affiliation(s)
- Jeffrey B Lee
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Abdullah Yonar
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
| | | | - Ching-Han Shen
- FAS Quantitative Biology Initiative, Center for Brain Science, Harvard University, Cambridge, MA, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Josselin Milloz
- FAS Quantitative Biology Initiative, Center for Brain Science, Harvard University, Cambridge, MA, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jagan Srinivasan
- Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Askin Kocabas
- FAS Quantitative Biology Initiative, Center for Brain Science, Harvard University, Cambridge, MA, USA.,Department of Physics, Koç University, Sarıyer, Istanbul, Turkey
| | - Sharad Ramanathan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA. .,Biophysics Program, Harvard University, Cambridge, MA, USA. .,FAS Quantitative Biology Initiative, Center for Brain Science, Harvard University, Cambridge, MA, USA. .,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA. .,Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA.
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36
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Guo M, Ge M, Berberoglu MA, Zhou J, Ma L, Yang J, Dong Q, Feng Y, Wu Z, Dong Z. Dissecting Molecular and Circuit Mechanisms for Inhibition and Delayed Response of ASI Neurons during Nociceptive Stimulus. Cell Rep 2018; 25:1885-1897.e9. [PMID: 30428355 DOI: 10.1016/j.celrep.2018.10.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/05/2018] [Accepted: 10/17/2018] [Indexed: 10/27/2022] Open
Abstract
The mechanisms by which off-response neurons stay quiescent during stimulation are largely unknown. Here, we dissect underlying molecular and circuit mechanisms for the inhibition of off-response ASI neurons during nociceptive Cu2+ stimulation. ASIs are inhibited in parallel by sensory neurons ASER, ADFs, and ASHs. ASER activates RIC interneurons that release octopamine (OA) to inhibit ASIs through SER-3 and SER-6 receptors. ADFs release 5-HT that acts on the SER-1 receptor to activate RICs and subsequently inhibit ASIs. Furthermore, it is an inherent property of ASIs that only a delayed on response is evoked by Cu2+ stimulation even when all inhibitory neurons are silenced. Ectopic expression of the ion channel OCR-2, which functions synergistically with OSM-9, in the cilia of ASIs can induce an immediate on response of ASIs upon Cu2+ stimulation. Our findings elucidate the molecular and circuit mechanisms regulating fundamental properties of ASIs, including their inhibition and delayed response.
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Affiliation(s)
- Min Guo
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Minghai Ge
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Michael A Berberoglu
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jie Zhou
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Long Ma
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Juan Yang
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiyan Dong
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yanni Feng
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhengxing Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Institute of Biophysics and Biochemistry, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhiqiang Dong
- Bio-Medical Center, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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37
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Mirzakhalili E, Epureanu BI, Gourgou E. A mathematical and computational model of the calcium dynamics in Caenorhabditis elegans ASH sensory neuron. PLoS One 2018; 13:e0201302. [PMID: 30048509 PMCID: PMC6062085 DOI: 10.1371/journal.pone.0201302] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/28/2018] [Indexed: 12/31/2022] Open
Abstract
We propose a mathematical and computational model that captures the stimulus-generated Ca2+ transients in the C. elegans ASH sensory neuron. The rationale is to develop a tool that will enable a cross-talk between modeling and experiments, using modeling results to guide targeted experimental efforts. The model is built based on biophysical events and molecular cascades known to unfold as part of neurons' Ca2+ homeostasis mechanism, as well as on Ca2+ signaling events. The state of ion channels is described by their probability of being activated or inactivated, and the remaining molecular states are based on biochemically defined kinetic equations or known biochemical motifs. We estimate the parameters of the model using experimental data of hyperosmotic stimulus-evoked Ca2+ transients detected with a FRET sensor in young and aged worms, unstressed and exposed to oxidative stress. We use a hybrid optimization method composed of a multi-objective genetic algorithm and nonlinear least-squares to estimate the model parameters. We first obtain the model parameters for young unstressed worms. Next, we use these values of the parameters as a starting point to identify the model parameters for stressed and aged worms. We show that the model, in combination with experimental data, corroborates literature results. In addition, we demonstrate that our model can be used to predict ASH response to complex combinations of stimulation pulses. The proposed model includes for the first time the ASH Ca2+ dynamics observed during both "on" and "off" responses. This mathematical and computational effort is the first to propose a dynamic model of the Ca2+ transients' mechanism in C. elegans neurons, based on biochemical pathways of the cell's Ca2+ homeostasis machinery. We believe that the proposed model can be used to further elucidate the Ca2+ dynamics of a key C. elegans neuron, to guide future experiments on C. elegans neurobiology, and to pave the way for the development of more mathematical models for neuronal Ca2+ dynamics.
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Affiliation(s)
- Ehsan Mirzakhalili
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bogdan I. Epureanu
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Eleni Gourgou
- Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, Division of Geriatrics, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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38
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Genetic dissection of neuropeptide cell biology at high and low activity in a defined sensory neuron. Proc Natl Acad Sci U S A 2018; 115:E6890-E6899. [PMID: 29959203 PMCID: PMC6055185 DOI: 10.1073/pnas.1714610115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuropeptides are ubiquitous modulators of behavior and physiology. They are packaged in specialized secretory organelles called dense core vesicles (DCVs) that are released upon neural stimulation. Whereas local recycling of synaptic vesicles has been investigated intensively, there are few studies on recycling of DCV proteins. We set up a paradigm to study DCVs in a neuron whose activity we can control. We validate our model by confirming many previous observations on DCV cell biology. We identify a set of genes involved in recycling of DCV proteins. We also find evidence that different mechanisms of DCV priming and exocytosis may operate at high and low neural activity. Neuropeptides are ubiquitous modulators of behavior and physiology. They are packaged in specialized secretory organelles called dense core vesicles (DCVs) that are released upon neural stimulation. Unlike synaptic vesicles, which can be recycled and refilled close to release sites, DCVs must be replenished by de novo synthesis in the cell body. Here, we dissect DCV cell biology in vivo in a Caenorhabditis elegans sensory neuron whose tonic activity we can control using a natural stimulus. We express fluorescently tagged neuropeptides in the neuron and define parameters that describe their subcellular distribution. We measure these parameters at high and low neural activity in 187 mutants defective in proteins implicated in membrane traffic, neuroendocrine secretion, and neuronal or synaptic activity. Using unsupervised hierarchical clustering methods, we analyze these data and identify 62 groups of genes with similar mutant phenotypes. We explore the function of a subset of these groups. We recapitulate many previous findings, validating our paradigm. We uncover a large battery of proteins involved in recycling DCV membrane proteins, something hitherto poorly explored. We show that the unfolded protein response promotes DCV production, which may contribute to intertissue communication of stress. We also find evidence that different mechanisms of priming and exocytosis may operate at high and low neural activity. Our work provides a defined framework to study DCV biology at different neural activity levels.
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McLachlan IG, Beets I, de Bono M, Heiman MG. A neuronal MAP kinase constrains growth of a Caenorhabditis elegans sensory dendrite throughout the life of the organism. PLoS Genet 2018; 14:e1007435. [PMID: 29879119 PMCID: PMC6007932 DOI: 10.1371/journal.pgen.1007435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 06/19/2018] [Accepted: 05/18/2018] [Indexed: 02/07/2023] Open
Abstract
Neurons develop elaborate morphologies that provide a model for understanding cellular architecture. By studying C. elegans sensory dendrites, we previously identified genes that act to promote the extension of ciliated sensory dendrites during embryogenesis. Interestingly, the nonciliated dendrite of the oxygen-sensing neuron URX is not affected by these genes, suggesting it develops through a distinct mechanism. Here, we use a visual forward genetic screen to identify mutants that affect URX dendrite morphogenesis. We find that disruption of the MAP kinase MAPK-15 or the βH-spectrin SMA-1 causes a phenotype opposite to what we had seen before: dendrites extend normally during embryogenesis but begin to overgrow as the animals reach adulthood, ultimately extending up to 150% of their normal length. SMA-1 is broadly expressed and acts non-cell-autonomously, while MAPK-15 is expressed in many sensory neurons including URX and acts cell-autonomously. MAPK-15 acts at the time of overgrowth, localizes at the dendrite ending, and requires its kinase activity, suggesting it acts locally in time and space to constrain dendrite growth. Finally, we find that the oxygen-sensing guanylate cyclase GCY-35, which normally localizes at the dendrite ending, is localized throughout the overgrown region, and that overgrowth can be suppressed by overexpressing GCY-35 or by genetically mimicking elevated cGMP signaling. These results suggest that overgrowth may correspond to expansion of a sensory compartment at the dendrite ending, reminiscent of the remodeling of sensory cilia or dendritic spines. Thus, in contrast to established pathways that promote dendrite growth during early development, our results reveal a distinct mechanism that constrains dendrite growth throughout the life of the animal, possibly by controlling the size of a sensory compartment at the dendrite ending.
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Affiliation(s)
- Ian G McLachlan
- Department of Genetics, Harvard Medical School and Boston Children's Hospital, Boston MA, United States of America
| | - Isabel Beets
- Division of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Mario de Bono
- Division of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Maxwell G Heiman
- Department of Genetics, Harvard Medical School and Boston Children's Hospital, Boston MA, United States of America
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Hussey R, Littlejohn NK, Witham E, Vanstrum E, Mesgarzadeh J, Ratanpal H, Srinivasan S. Oxygen-sensing neurons reciprocally regulate peripheral lipid metabolism via neuropeptide signaling in Caenorhabditis elegans. PLoS Genet 2018; 14:e1007305. [PMID: 29579048 PMCID: PMC5886693 DOI: 10.1371/journal.pgen.1007305] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 04/05/2018] [Accepted: 03/11/2018] [Indexed: 01/14/2023] Open
Abstract
The mechanisms by which the sensory environment influences metabolic homeostasis remains poorly understood. In this report, we show that oxygen, a potent environmental signal, is an important regulator of whole body lipid metabolism. C. elegans oxygen-sensing neurons reciprocally regulate peripheral lipid metabolism under normoxia in the following way: under high oxygen and food absence, URX sensory neurons are activated, and stimulate fat loss in the intestine, the major metabolic organ for C. elegans. Under lower oxygen conditions or when food is present, the BAG sensory neurons respond by repressing the resting properties of the URX neurons. A genetic screen to identify modulators of this effect led to the identification of a BAG-neuron-specific neuropeptide called FLP-17, whose cognate receptor EGL-6 functions in URX neurons. Thus, BAG sensory neurons counterbalance the metabolic effect of tonically active URX neurons via neuropeptide communication. The combined regulatory actions of these neurons serve to precisely tune the rate and extent of fat loss to the availability of food and oxygen, and provides an interesting example of the myriad mechanisms underlying homeostatic control.
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Affiliation(s)
- Rosalind Hussey
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Nicole K. Littlejohn
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Emily Witham
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Erik Vanstrum
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Jaleh Mesgarzadeh
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
- Department of Biology, University of California, San Diego, La Jolla, CA, United States of America
| | - Harkaranveer Ratanpal
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Supriya Srinivasan
- Department of Molecular Medicine and Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, United States of America
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Chen YH, Ge CL, Wang H, Ge MH, He QQ, Zhang Y, Tian W, Wu ZX. GCY-35/GCY-36-TAX-2/TAX-4 Signalling in O 2 Sensory Neurons Mediates Acute Functional Ethanol Tolerance in Caenorhabditis elegans. Sci Rep 2018; 8:3020. [PMID: 29445226 PMCID: PMC5813177 DOI: 10.1038/s41598-018-20477-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 01/18/2018] [Indexed: 11/29/2022] Open
Abstract
Ethanol is a widely used beverage and abused drug. Alcoholism causes severe damage to human health and creates serious social problems. Understanding the mechanisms underlying ethanol actions is important for the development of effective therapies. Alcohol has a wide spectrum of effects on physiological activities and behaviours, from sensitization to sedation and even intoxication with increasing concentrations. Animals develop tolerance to ethanol. However, the underlying mechanisms are not well understood. In Caenorhabditis elegans, NPR-1 negatively regulates the development of acute tolerance to ethanol. Here, using in vivo Ca2+ imaging, behavioural tests and chemogenetic manipulation, we show that the soluble guanylate cyclase complex GCY-35/GCY-36-TAX-2/TAX-4 signalling pathway in O2 sensory neurons positively regulates acute functional tolerance in npr-1 worms.
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Affiliation(s)
- Yuan-Hua Chen
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Chang-Li Ge
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Hong Wang
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Ming-Hai Ge
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Qing-Qin He
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Yu Zhang
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Wei Tian
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Zheng-Xing Wu
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Department of Biophysics and Molecular Physiology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
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42
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Skora S, Mende F, Zimmer M. Energy Scarcity Promotes a Brain-wide Sleep State Modulated by Insulin Signaling in C. elegans. Cell Rep 2018; 22:953-966. [PMID: 29386137 PMCID: PMC5846868 DOI: 10.1016/j.celrep.2017.12.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 11/16/2017] [Accepted: 12/23/2017] [Indexed: 12/17/2022] Open
Abstract
Neural information processing entails a high energetic cost, but its maintenance is crucial for animal survival. However, the brain’s energy conservation strategies are incompletely understood. Employing functional brain-wide imaging and quantitative behavioral assays, we describe a neuronal strategy in Caenorhabditis elegans that balances energy availability and expenditure. Upon acute food deprivation, animals exhibit a transiently elevated state of arousal, indicated by foraging behaviors and increased responsiveness to food-related cues. In contrast, long-term starvation suppresses these behaviors and biases animals to intermittent sleep episodes. Brain-wide neuronal population dynamics, which are likely energetically costly but important for behavior, are robust to starvation while animals are awake. However, during starvation-induced sleep, brain dynamics are systemically downregulated. Neuromodulation via insulin-like signaling is required to transiently maintain the animals’ arousal state upon acute food deprivation. Our data suggest that the regulation of sleep and wakefulness supports optimal energy allocation. Starvation shifts the behavioral strategy from exploration to intermittent sleep Brain-wide neuronal population dynamics are robust to starvation Neuromodulation via insulin signaling maintains wakefulness during short fasting The insulin receptor DAF-2 acts in a network of sensory neurons and interneurons
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Affiliation(s)
- Susanne Skora
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Fanny Mende
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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43
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The extraordinary AFD thermosensor of C. elegans. Pflugers Arch 2017; 470:839-849. [PMID: 29218454 DOI: 10.1007/s00424-017-2089-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
The nematode C. elegans exhibits complex thermal experience-dependent navigation behaviors in response to environmental temperature changes of as little as 0.01°C over a > 10°C temperature range. The remarkable thermosensory abilities of this animal are mediated primarily via the single pair of AFD sensory neurons in its head. In this review, we describe the contributions of AFD to thermosensory behaviors and temperature-dependent regulation of organismal physiology. We also discuss the mechanisms that enable this neuron type to adapt to recent temperature experience and to exhibit extraordinary thermosensitivity over a wide dynamic range.
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44
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An oxytocin-dependent social interaction between larvae and adult C. elegans. Sci Rep 2017; 7:10122. [PMID: 28860630 PMCID: PMC5579267 DOI: 10.1038/s41598-017-09350-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 07/26/2017] [Indexed: 12/21/2022] Open
Abstract
Oxytocin has a conserved role in regulating animal social behaviour including parental-offspring interactions. Recently an oxytocin-like neuropeptide, nematocin, and its cognate receptors have been identified in the nematode Caenorhabditis elegans. We provide evidence for a pheromone signal produced by C. elegans larvae that modifies the behaviour of adult animals in an oxytocin-dependent manner increasing their probability of leaving a food patch which the larvae are populating. This increase is positively correlated to the size of the larval population but cannot be explained by food depletion nor is it modulated by biogenic amines, which suggest it is not an aversive behaviour. Moreover, the food-leaving behaviour is conspecific and pheromone dependent: C. elegans adults respond more strongly to C. elegans larvae compared to other nematode species and this effect is absent in C. elegans daf-22 larvae which are pheromone deficient. Neurotransmitter receptors previously implicated in C. elegans foraging decisions NPR-1 and TYRA-3, for NPY-like neuropeptides and tyramine respectively, do not appear to be involved in oxytocin-dependent adult food-leaving. We conclude oxytocin signals within a novel neural circuit that regulates parental-offspring social behaviour in C. elegans and that this provides evidence for evolutionary conservation of molecular components of a parental decision making behaviour.
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Abstract
How the brain effectively switches between and maintains global states, such as sleep and wakefulness, is not yet understood. We used brainwide functional imaging at single-cell resolution to show that during the developmental stage of lethargus, the Caenorhabditis elegans brain is predisposed to global quiescence, characterized by systemic down-regulation of neuronal activity. Only a few specific neurons are exempt from this effect. In the absence of external arousing cues, this quiescent brain state arises by the convergence of neuronal activities toward a fixed-point attractor embedded in an otherwise dynamic neural state space. We observed efficient spontaneous and sensory-evoked exits from quiescence. Our data support the hypothesis that during global states such as sleep, neuronal networks are drawn to a baseline mode and can be effectively reactivated by signaling from arousing circuits.
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Affiliation(s)
- Annika L A Nichols
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Tomáš Eichler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Richard Latham
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Manuel Zimmer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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46
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Modulation of sensory information processing by a neuroglobin in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:E4658-E4665. [PMID: 28536200 DOI: 10.1073/pnas.1614596114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sensory receptor neurons match their dynamic range to ecologically relevant stimulus intensities. How this tuning is achieved is poorly understood in most receptors. The roundworm Caenorhabditis elegans avoids 21% O2 and hypoxia and prefers intermediate O2 concentrations. We show how this O2 preference is sculpted by the antagonistic action of a neuroglobin and an O2-binding soluble guanylate cyclase. These putative molecular O2 sensors confer a sigmoidal O2 response curve in the URX neurons that has highest slope between 15 and 19% O2 and approaches saturation when O2 reaches 21%. In the absence of the neuroglobin, the response curve is shifted to lower O2 values and approaches saturation at 14% O2 In behavioral terms, neuroglobin signaling broadens the O2 preference of Caenorhabditis elegans while maintaining avoidance of 21% O2 A computational model of aerotaxis suggests the relationship between GLB-5-modulated URX responses and reversal behavior is sufficient to broaden O2 preference. In summary, we show that a neuroglobin can shift neural information coding leading to altered behavior. Antagonistically acting molecular sensors may represent a common mechanism to sharpen tuning of sensory neurons.
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47
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Tanimoto Y, Yamazoe-Umemoto A, Fujita K, Kawazoe Y, Miyanishi Y, Yamazaki SJ, Fei X, Busch KE, Gengyo-Ando K, Nakai J, Iino Y, Iwasaki Y, Hashimoto K, Kimura KD. Calcium dynamics regulating the timing of decision-making in C. elegans. eLife 2017; 6:e21629. [PMID: 28532547 PMCID: PMC5441874 DOI: 10.7554/elife.21629] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 04/23/2017] [Indexed: 12/28/2022] Open
Abstract
Brains regulate behavioral responses with distinct timings. Here we investigate the cellular and molecular mechanisms underlying the timing of decision-making during olfactory navigation in Caenorhabditis elegans. We find that, based on subtle changes in odor concentrations, the animals appear to choose the appropriate migratory direction from multiple trials as a form of behavioral decision-making. Through optophysiological, mathematical and genetic analyses of neural activity under virtual odor gradients, we further find that odor concentration information is temporally integrated for a decision by a gradual increase in intracellular calcium concentration ([Ca2+]i), which occurs via L-type voltage-gated calcium channels in a pair of olfactory neurons. In contrast, for a reflex-like behavioral response, [Ca2+]i rapidly increases via multiple types of calcium channels in a pair of nociceptive neurons. Thus, the timing of neuronal responses is determined by cell type-dependent involvement of calcium channels, which may serve as a cellular basis for decision-making.
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Affiliation(s)
- Yuki Tanimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Akiko Yamazoe-Umemoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Kosuke Fujita
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Yuya Kawazoe
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Yosuke Miyanishi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Shuhei J Yamazaki
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Xianfeng Fei
- Faculty of Science and Technology, Tohoku Bunka Gakuen University, Sendai, Japan
| | - Karl Emanuel Busch
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, United Kingdom
| | - Keiko Gengyo-Ando
- Graduate Shool of Science and Engineering, Brain and Body System Science Institute, Saitama University, Saitama, Japan
| | - Junichi Nakai
- Graduate Shool of Science and Engineering, Brain and Body System Science Institute, Saitama University, Saitama, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yuishi Iwasaki
- Department of Intelligent Systems Engineering, Ibaraki University, Hitachi, Japan
| | - Koichi Hashimoto
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Koutarou D Kimura
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
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An Aversive Response to Osmotic Upshift in Caenorhabditis elegans. eNeuro 2017; 4:eN-NWR-0282-16. [PMID: 28451641 PMCID: PMC5399755 DOI: 10.1523/eneuro.0282-16.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 12/12/2022] Open
Abstract
Environmental osmolarity presents a common type of sensory stimulus to animals. While behavioral responses to osmotic changes are important for maintaining a stable intracellular osmolarity, the underlying mechanisms are not fully understood. In the natural habitat of Caenorhabditis elegans, changes in environmental osmolarity are commonplace. It is known that the nematode acutely avoids shocks of extremely high osmolarity. Here, we show that C. elegans also generates gradually increased aversion of mild upshifts in environmental osmolarity. Different from an acute avoidance of osmotic shocks that depends on the function of a transient receptor potential vanilloid channel, the slow aversion to osmotic upshifts requires the cGMP-gated sensory channel subunit TAX-2. TAX-2 acts in several sensory neurons that are exposed to body fluid to generate the aversive response through a motor network that underlies navigation. Osmotic upshifts activate the body cavity sensory neuron URX, which is known to induce aversion upon activation. Together, our results characterize the molecular and cellular mechanisms underlying a novel sensorimotor response to osmotic stimuli and reveal that C. elegans engages different behaviors and the underlying mechanisms to regulate responses to extracellular osmolarity.
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49
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Memory of recent oxygen experience switches pheromone valence in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:4195-4200. [PMID: 28373553 DOI: 10.1073/pnas.1618934114] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animals adjust their behavioral priorities according to momentary needs and prior experience. We show that Caenorhabditis elegans changes how it processes sensory information according to the oxygen environment it experienced recently. C. elegans acclimated to 7% O2 are aroused by CO2 and repelled by pheromones that attract animals acclimated to 21% O2 This behavioral plasticity arises from prolonged activity differences in a circuit that continuously signals O2 levels. A sustained change in the activity of O2-sensing neurons reprograms the properties of their postsynaptic partners, the RMG hub interneurons. RMG is gap-junctionally coupled to the ASK and ADL pheromone sensors that respectively drive pheromone attraction and repulsion. Prior O2 experience has opposite effects on the pheromone responsiveness of these neurons. These circuit changes provide a physiological correlate of altered pheromone valence. Our results suggest C. elegans stores a memory of recent O2 experience in the RMG circuit and illustrate how a circuit is flexibly sculpted to guide behavioral decisions in a context-dependent manner.
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50
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Dissection of neuronal gap junction circuits that regulate social behavior in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:E1263-E1272. [PMID: 28143932 DOI: 10.1073/pnas.1621274114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A hub-and-spoke circuit of neurons connected by gap junctions controls aggregation behavior and related behavioral responses to oxygen, pheromones, and food in Caenorhabditis elegans The molecular composition of the gap junctions connecting RMG hub neurons with sensory spoke neurons is unknown. We show here that the innexin gene unc-9 is required in RMG hub neurons to drive aggregation and related behaviors, indicating that UNC-9-containing gap junctions mediate RMG signaling. To dissect the circuit in detail, we developed methods to inhibit unc-9-based gap junctions with dominant-negative unc-1 transgenes. unc-1(dn) alters a stomatin-like protein that regulates unc-9 electrical signaling; its disruptive effects can be rescued by a constitutively active UNC-9::GFP protein, demonstrating specificity. Expression of unc-1(dn) in RMG hub neurons, ADL or ASK pheromone-sensing neurons, or URX oxygen-sensing neurons disrupts specific elements of aggregation-related behaviors. In ADL, unc-1(dn) has effects opposite to those of tetanus toxin light chain, separating the roles of ADL electrical and chemical synapses. These results reveal roles of gap junctions in a complex behavior at cellular resolution and provide a tool for similar exploration of other gap junction circuits.
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