1
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Toker IA, Ripoll-Sánchez L, Geiger LT, Sussfeld A, Saini KS, Beets I, Vértes PE, Schafer WR, Ben-David E, Hobert O. Divergence in neuronal signaling pathways despite conserved neuronal identity among Caenorhabditis species. Curr Biol 2025:S0960-9822(25)00652-9. [PMID: 40412379 DOI: 10.1016/j.cub.2025.05.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2025] [Revised: 05/13/2025] [Accepted: 05/14/2025] [Indexed: 05/27/2025]
Abstract
One avenue to better understand brain evolution is to map molecular patterns of evolutionary changes in neuronal cell types across entire nervous systems of distantly related species. Generating whole-animal single-cell transcriptomes of three nematode species from the Caenorhabditis genus, we observed a remarkable stability of neuronal-cell-type identities over more than 45 million years of evolution. Conserved patterns of combinatorial expression of homeodomain transcription factors are among the best classifiers of homologous neuron classes. Unexpectedly, we discover an extensive divergence in neuronal signaling pathways. Although identities of neurotransmitter-producing neurons (glutamate, acetylcholine, γ-aminobutyric acid [GABA], and several monoamines) remain stable, expression of ionotropic and metabotropic receptors for all these neurotransmitter systems shows substantial divergence, resulting in more than half of all neuron classes changing their capacity to be receptive to specific neurotransmitters. Neuropeptidergic signaling is also remarkably divergent, both at the level of neuropeptide expression and receptor expression, yet the overall dense network topology of the wireless neuropeptidergic connectome remains stable. Novel neuronal signaling pathways are suggested by our discovery of small secreted proteins that show no obvious hallmarks of conventional neuropeptides but show similar patterns of highly neuron-type-specific and highly evolvable expression profiles. In conclusion, by investigating the evolution of entire nervous systems at the resolution of single-neuron classes, we uncover patterns that may reflect basic principles governing evolutionary novelty in neuronal circuits.
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Affiliation(s)
- Itai Antoine Toker
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA.
| | - Lidia Ripoll-Sánchez
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Psychiatry, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Luke T Geiger
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Antoine Sussfeld
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Karan S Saini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Isabel Beets
- Department of Biology, KU of Leuven, 3000 Leuven, Belgium
| | - Petra E Vértes
- Department of Psychiatry, University of Cambridge, Cambridge CB2 0SZ, UK
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Biology, KU of Leuven, 3000 Leuven, Belgium
| | - Eyal Ben-David
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA.
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2
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Hernandez-Lima MA, Seo B, Urban ND, Truttmann MC. Modulation of C. elegans behavior, fitness, and lifespan by AWB/ASH-dependent death perception. Curr Biol 2025; 35:2128-2138.e6. [PMID: 40250434 PMCID: PMC12055480 DOI: 10.1016/j.cub.2025.03.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2024] [Revised: 02/24/2025] [Accepted: 03/27/2025] [Indexed: 04/20/2025]
Abstract
The ability of the nervous system to initiate intricate goal-directed behaviors in response to environmental stimuli is essential for metazoan survival. In this study, we demonstrate that the nematode Caenorhabditis elegans perceives and reacts to dead conspecifics. The exposure to C. elegans corpses, as well as corpse lysates, activates sensory neurons AWB and ASH, triggering a glutamate- and acetylcholine-dependent signaling cascade that regulates both immediate (aversion) and long-term (survival) responses to the presence of a death signature. We identify increased adenosine monophosphate (AMP) and histidine concentrations as potential chemical fingerprints for the presence of metazoan corpses and show that death cue sensing by AWB and ASH leads to physiological changes that promote reproduction at the expense of lifespan. Our findings illuminate a signaling paradigm that allows organisms to detect and interpret the environmental enrichment of intracellular metabolites as a death cue.
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Affiliation(s)
- Mirella A Hernandez-Lima
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brian Seo
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas D Urban
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Graduate Program in Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Matthias C Truttmann
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Graduate Program in Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Geriatrics Center, University of Michigan, Ann Arbor, MI 48109, USA.
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3
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Sojka SE, Ezak MJ, Polk EA, Bischer AP, Neyland KE, Wojtovich AP, Ferkey DM. An Extensive Gap Junction Neural Network Modulates Caenorhabditis elegans Aversive Behavior. Genes (Basel) 2025; 16:260. [PMID: 40149412 PMCID: PMC11941935 DOI: 10.3390/genes16030260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2025] [Revised: 02/17/2025] [Accepted: 02/18/2025] [Indexed: 03/29/2025] Open
Abstract
BACKGROUND/OBJECTIVES Caenorhabditis elegans rely on sensory perception of environmental cues for survival in their native soil and compost habitats. These cues provide information about nutrient availability, mating partners, or predatory and hazardous beacons. In C. elegans, the two bilaterally-symmetric head sensory neurons termed ASH are the main detectors of aversive nociceptive signals. Through their downstream connections in the nervous system, ASH activation causes the animal to initiate backward locomotion to escape and avoid the harmful stimulus. Modulation of avoidance behavior allows for situation-appropriate sensitivity and response to stimuli. We previously reported a role for gap junctions in the transport of regulatory cGMP to the ASHs where it functions to dampen avoidance responses. METHODS Here, we used genetic mutants and a combination of cell-selective rescue and knockdown experiments to identify gap junction proteins (innexins) involved in modulating ASH-mediated nociceptive behavioral responses. RESULTS We have characterized six additional C. elegans innexins that have overlapping and distinct roles within this regulatory network: INX-7, INX-15, INX-16, INX-17, UNC-7, and UNC-9. CONCLUSIONS This work expands our understanding of the extent to which ASH sensitivity can be tuned in a non-cell-autonomous manner.
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Affiliation(s)
- Savannah E. Sojka
- Ferkey Laboratory, Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Meredith J. Ezak
- Ferkey Laboratory, Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Emily A. Polk
- Ferkey Laboratory, Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Andrew P. Bischer
- Wojtovich Laboratory, Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Katherine E. Neyland
- Wojtovich Laboratory, Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Andrew P. Wojtovich
- Wojtovich Laboratory, Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Denise M. Ferkey
- Ferkey Laboratory, Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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4
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Toker IA, Ripoll-Sánchez L, Geiger LT, Saini KS, Beets I, Vértes PE, Schafer WR, Ben-David E, Hobert O. Molecular patterns of evolutionary changes throughout the whole nervous system of multiple nematode species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.11.23.624988. [PMID: 39651161 PMCID: PMC11623510 DOI: 10.1101/2024.11.23.624988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2024]
Abstract
One avenue to better understand brain evolution is to map molecular patterns of evolutionary changes in neuronal cell types across entire nervous systems of distantly related species. Generating whole-animal single-cell transcriptomes of three nematode species from the Caenorhabditis genus, we observed a remarkable stability of neuronal cell type identities over more than 45 million years of evolution. Conserved patterns of combinatorial expression of homeodomain transcription factors are among the best classifiers of homologous neuron classes. Unexpectedly, we discover an extensive divergence in neuronal signaling pathways. While identities of neurotransmitter-producing neurons (glutamate, acetylcholine, GABA and several monoamines) remain stable, ionotropic and metabotropic receptors for all these neurotransmitter systems show substantial divergence, resulting in more than half of all neuron classes changing their capacity to be receptive to specific neurotransmitters. Neuropeptidergic signaling is also remarkably divergent, both at the level of neuropeptide expression and receptor expression, yet the overall dense network topology of the wireless neuropeptidergic connectome remains stable. Novel neuronal signaling pathways are suggested by our discovery of small secreted proteins that show no obvious hallmarks of conventional neuropeptides, but show similar patterns of highly neuron-type-specific and highly evolvable expression profiles. In conclusion, by investigating the evolution of entire nervous systems at the resolution of single neuron classes, we uncover patterns that may reflect basic principles governing evolutionary novelty in neuronal circuits.
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5
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Hernandez-Lima MA, Seo B, Urban ND, Truttmann MC. C. elegans behavior, fitness, and lifespan, are modulated by AWB/ASH-dependent death perception. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.07.617097. [PMID: 39416137 PMCID: PMC11482816 DOI: 10.1101/2024.10.07.617097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
The ability of the nervous system to initiate intricate goal-directed behaviors in response to environmental stimuli is essential for metazoan survival. In this study, we demonstrate that the nematode Caenorhabditis elegans perceives and reacts to dead conspecifics. The exposure to C. elegans corpses as well as corpse lysates activates sensory neurons AWB and ASH, triggering a glutamate- and acetylcholine-dependent signaling cascade that regulates both immediate (aversion) and long-term (survival) responses to the presence of a death signature. We identify increased adenosine monophosphate (AMP) and cysteine concentrations as chemical fingerprints for the presence of metazoan corpses and show that death cue sensing by AWB and ASH leads to physiological changes which promote reproduction at the expense of lifespan. Our findings illuminate a novel signaling paradigm that allows organisms to detect and interpret the environmental enrichment of intracellular metabolites as a death cue.
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Affiliation(s)
- Mirella A. Hernandez-Lima
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Brian Seo
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nicholas D. Urban
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
- Graduate Program in Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Matthias C. Truttmann
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
- Graduate Program in Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
- Geriatrics Center, University of Michigan, Ann Arbor, MI, 48109, USA
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6
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Bokman E, Pritz CO, Ruach R, Itskovits E, Sharvit H, Zaslaver A. Intricate response dynamics enhances stimulus discrimination in the resource-limited C. elegans chemosensory system. BMC Biol 2024; 22:173. [PMID: 39148065 PMCID: PMC11328493 DOI: 10.1186/s12915-024-01977-z] [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: 02/12/2024] [Accepted: 08/08/2024] [Indexed: 08/17/2024] Open
Abstract
BACKGROUND Sensory systems evolved intricate designs to accurately encode perplexing environments. However, this encoding task may become particularly challenging for animals harboring a small number of sensory neurons. Here, we studied how the compact resource-limited chemosensory system of Caenorhabditis elegans uniquely encodes a range of chemical stimuli. RESULTS We find that each stimulus is encoded using a small and unique subset of neurons, where only a portion of the encoding neurons sense the stimulus directly, and the rest are recruited via inter-neuronal communication. Furthermore, while most neurons show stereotypical response dynamics, some neurons exhibit versatile dynamics that are either stimulus specific or network-activity dependent. Notably, it is the collective dynamics of all responding neurons which provides valuable information that ultimately enhances stimulus identification, particularly when required to discriminate between closely related stimuli. CONCLUSIONS Together, these findings demonstrate how a compact and resource-limited chemosensory system can efficiently encode and discriminate a diverse range of chemical stimuli.
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Affiliation(s)
- Eduard Bokman
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Christian O Pritz
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rotem Ruach
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eyal Itskovits
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadar Sharvit
- Department of Statistics and Data Science, Center for Interdisciplinary Data Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alon Zaslaver
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel.
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7
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Chaubey AH, Sojka SE, Onukwufor JO, Ezak MJ, Vandermeulen MD, Bowitch A, Vodičková A, Wojtovich AP, Ferkey DM. The Caenorhabditis elegans innexin INX-20 regulates nociceptive behavioral sensitivity. Genetics 2023; 223:iyad017. [PMID: 36753530 PMCID: PMC10319955 DOI: 10.1093/genetics/iyad017] [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: 09/03/2022] [Revised: 09/03/2022] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Organisms rely on chemical cues in their environment to indicate the presence or absence of food, reproductive partners, predators, or other harmful stimuli. In the nematode Caenorhabditis elegans, the bilaterally symmetric pair of ASH sensory neurons serves as the primary nociceptors. ASH activation by aversive stimuli leads to backward locomotion and stimulus avoidance. We previously reported a role for guanylyl cyclases in dampening nociceptive sensitivity that requires an innexin-based gap junction network to pass cGMP between neurons. Here, we report that animals lacking function of the gap junction component INX-20 are hypersensitive in their behavioral response to both soluble and volatile chemical stimuli that signal through G protein-coupled receptor pathways in ASH. We find that expressing inx-20 in the ADL and AFD sensory neurons is sufficient to dampen ASH sensitivity, which is supported by new expression analysis of endogenous INX-20 tagged with mCherry via the CRISPR-Cas9 system. Although ADL does not form gap junctions directly with ASH, it does so via gap junctions with the interneuron RMG and the sensory neuron ASK. Ablating either ADL or RMG and ASK also resulted in nociceptive hypersensitivity, suggesting an important role for RMG/ASK downstream of ADL in the ASH modulatory circuit. This work adds to our growing understanding of the repertoire of ways by which ASH activity is regulated via its connectivity to other neurons and identifies a previously unknown role for ADL and RMG in the modulation of aversive behavior.
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Affiliation(s)
- Aditi H Chaubey
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Savannah E Sojka
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - John O Onukwufor
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Meredith J Ezak
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Matthew D Vandermeulen
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Alexander Bowitch
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
| | - Anežka Vodičková
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Andrew P Wojtovich
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
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8
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Positive interaction between ASH and ASK sensory neurons accelerates nociception and inhibits behavioral adaptation. iScience 2022; 25:105287. [PMID: 36304123 PMCID: PMC9593764 DOI: 10.1016/j.isci.2022.105287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/22/2022] [Accepted: 10/04/2022] [Indexed: 11/23/2022] Open
Abstract
Central and peripheral sensory neurons tightly regulate nociception and avoidance behavior. The peripheral modulation of nociception provides more veridical and instantaneous information for animals to achieve rapid, more fine-tuned and concentrated behavioral responses. In this study, we find that positive interaction between ASH and ASK sensory neurons is essential for the fast-rising phase of ASH Ca2+ responses to noxious copper ions and inhibits the adaption of avoiding Cu2+. We reveal the underlying neuronal circuit mechanism. ASK accelerates the ASH Ca2+ responses by transferring cGMP through gap junctions. ASH excites ASK via a disinhibitory neuronal circuit composed of ASH, AIA, and ASK. Avoidance adaptation depends on the slope rate of the rising phase of ASH Ca2+ responses. Thus, in addition to amplitude, sensory kinetics is significant for sensations and behaviors, especially for sensory and behavioral adaptations.
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9
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Hino T, Hirai S, Ishihara T, Fujiwara M. EGL-4/PKG regulates the role of an interneuron in a chemotaxis circuit of C. elegans through mediating integration of sensory signals. Genes Cells 2021; 26:411-425. [PMID: 33817914 DOI: 10.1111/gtc.12849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
Interneurons, innervated by multiple sensory neurons, need to integrate information from these sensory neurons and respond to sensory stimuli adequately. Mechanisms how sensory information is integrated to form responses of interneurons are not fully understood. In Caenorhabditis elegans, loss-of-function mutations of egl-4, which encodes a cGMP-dependent protein kinase (PKG), cause a defect in chemotaxis to odorants. Our genetic and imaging analyses revealed that the response property of AIY interneuron to an odorant is reversed in the egl-4 mutant, while the responses of two upstream olfactory neurons, AWA and AWC, are largely unchanged. Cell- ablation experiments show that AIY in the egl-4 mutant functions to suppress chemotaxis. Furthermore, the reversal of AIY response occurs only in the presence of sensory signals from both AWA and AWC. These results suggest that sensory signals are inadequately integrated in the egl-4 mutant. We also show that egl-4 expression in AWA and another sensory neuron prevents the reversed AIY response and restores chemotaxis in the egl-4 mutants. We propose that EGL-4/PKG, by suppressing aberrant integration of signals from olfactory neurons, converts the response property of an interneuron to olfactory stimuli and maintains the role of the interneuron in the circuit to execute chemotactic behavior.
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Affiliation(s)
- Takahiro Hino
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Shota Hirai
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Takeshi Ishihara
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Manabi Fujiwara
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
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10
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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11
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C. elegans episodic swimming is driven by multifractal kinetics. Sci Rep 2020; 10:14775. [PMID: 32901071 PMCID: PMC7478975 DOI: 10.1038/s41598-020-70319-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/27/2020] [Indexed: 12/21/2022] Open
Abstract
Fractal scaling is a common property of temporal change in various modes of animal behavior. The molecular mechanisms of fractal scaling in animal behaviors remain largely unexplored. The nematode C. elegans alternates between swimming and resting states in a liquid solution. Here, we report that C. elegans episodic swimming is characterized by scale-free kinetics with long-range temporal correlation and local temporal clusterization, namely consistent with multifractal kinetics. Residence times in actively-moving and inactive states were distributed in a power law-based scale-free manner. Multifractal analysis showed that temporal correlation and temporal clusterization were distinct between the actively-moving state and the inactive state. These results indicate that C. elegans episodic swimming is driven by transition between two behavioral states, in which each of two transition kinetics follows distinct multifractal kinetics. We found that a conserved behavioral modulator, cyclic GMP dependent kinase (PKG) may regulate the multifractal kinetics underlying an animal behavior. Our combinatorial analysis approach involving molecular genetics and kinetics provides a platform for the molecular dissection of the fractal nature of physiological and behavioral phenomena.
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12
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Park J, Meisel JD, Kim DH. Immediate activation of chemosensory neuron gene expression by bacterial metabolites is selectively induced by distinct cyclic GMP-dependent pathways in Caenorhabditis elegans. PLoS Genet 2020; 16:e1008505. [PMID: 32776934 PMCID: PMC7416920 DOI: 10.1371/journal.pgen.1008505] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 06/15/2020] [Indexed: 01/19/2023] Open
Abstract
Dynamic gene expression in neurons shapes fundamental processes in the nervous systems of animals. However, how neuronal activation by different stimuli can lead to distinct transcriptional responses is not well understood. We have been studying how microbial metabolites modulate gene expression in chemosensory neurons of Caenorhabditis elegans. Considering the diverse environmental stimuli that can activate chemosensory neurons of C. elegans, we sought to understand how specific transcriptional responses can be generated in these neurons in response to distinct cues. We have focused on the mechanism of rapid (<6 min) and selective transcriptional induction of daf-7, a gene encoding a TGF-β ligand, in the ASJ chemosensory neurons in response to the pathogenic bacterium Pseudomonas aeruginosa. DAF-7 is required for the protective behavioral avoidance of P. aeruginosa by C. elegans. Here, we define the involvement of two distinct cyclic GMP (cGMP)-dependent pathways that are required for daf-7 expression in the ASJ neuron pair in response to P. aeruginosa. We show that a calcium-independent pathway dependent on the cGMP-dependent protein kinase G (PKG) EGL-4, and a canonical calcium-dependent signaling pathway dependent on the activity of a cyclic nucleotide-gated channel subunit CNG-2, function in parallel to activate rapid, selective transcription of daf-7 in response to P. aeruginosa metabolites. Our data suggest that fast, selective early transcription of neuronal genes require PKG in shaping responses to distinct microbial stimuli in a pair of C. elegans chemosensory neurons.
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Affiliation(s)
- Jaeseok Park
- Division of Infectious Diseases, Boston Children’s Hospital, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Dennis H. Kim
- Division of Infectious Diseases, Boston Children’s Hospital, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
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13
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Mehle EA, Sojka SE, K C M, Zel RM, Reese SJ, Ferkey DM. The C. elegans TRPV channel proteins OSM-9 and OCR-2 contribute to aversive chemical sensitivity. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 32666046 PMCID: PMC7352062 DOI: 10.17912/micropub.biology.000277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emily A Mehle
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Savannah E Sojka
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Medha K C
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Rosy M Zel
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Sebastian J Reese
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
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14
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Voelker L, Upadhyaya B, Ferkey DM, Woldemariam S, L’Etoile ND, Rabinowitch I, Bai J. INX-18 and INX-19 play distinct roles in electrical synapses that modulate aversive behavior in Caenorhabditis elegans. PLoS Genet 2019; 15:e1008341. [PMID: 31658255 PMCID: PMC6837551 DOI: 10.1371/journal.pgen.1008341] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/07/2019] [Accepted: 10/04/2019] [Indexed: 12/23/2022] Open
Abstract
In order to respond to changing environments and fluctuations in internal states, animals adjust their behavior through diverse neuromodulatory mechanisms. In this study we show that electrical synapses between the ASH primary quinine-detecting sensory neurons and the neighboring ASK neurons are required for modulating the aversive response to the bitter tastant quinine in C. elegans. Mutant worms that lack the electrical synapse proteins INX-18 and INX-19 become hypersensitive to dilute quinine. Cell-specific rescue experiments indicate that inx-18 operates in ASK while inx-19 is required in both ASK and ASH for proper quinine sensitivity. Imaging analyses find that INX-19 in ASK and ASH localizes to the same regions in the nerve ring, suggesting that both sides of ASK-ASH electrical synapses contain INX-19. While inx-18 and inx-19 mutant animals have a similar behavioral phenotype, several lines of evidence suggest the proteins encoded by these genes play different roles in modulating the aversive quinine response. First, INX-18 and INX-19 localize to different regions of the nerve ring, indicating that they are not present in the same synapses. Second, removing inx-18 disrupts the distribution of INX-19, while removing inx-19 does not alter INX-18 localization. Finally, by using a fluorescent cGMP reporter, we find that INX-18 and INX-19 have distinct roles in establishing cGMP levels in ASK and ASH. Together, these results demonstrate that electrical synapses containing INX-18 and INX-19 facilitate modulation of ASH nociceptive signaling. Our findings support the idea that a network of electrical synapses mediates cGMP exchange between neurons, enabling modulation of sensory responses and behavior. Animals are constantly adjusting their behavior to respond to changes in the environment or to their internal state. This behavior modulation is achieved by altering the activity of neurons and circuits through a variety of neuroplasticity mechanisms. Chemical synapses are known to impact neuroplasticity in several different ways, but the diversity of mechanisms by which electrical synapses contribute is still being investigated. Electrical synapses are specialized sites of connection between neurons where ions and small signaling molecules can pass directly from one cell to the next. By passing small molecules through electrical synapses, neurons may be able to modify the activity of their neighbors. In this study we identify two genes that contribute to electrical synapses between two sensory neurons in C. elegans. We show that these electrical synapses are crucial for proper modulation of sensory responses, as without them animals are overly responsive to an aversive stimulus. In addition to pinpointing their sites of action, we present evidence that they may be contributing to neuromodulation by facilitating passage of the small molecule cGMP between neurons. Our work provides evidence for a role of electrical synapses in regulating animal behavior.
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Affiliation(s)
- Lisa Voelker
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, United States of America
| | - Bishal Upadhyaya
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Denise M. Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States of America
| | - Sarah Woldemariam
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, United States of America
| | - Noelle D. L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, United States of America
| | - Ithai Rabinowitch
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Department of Medical Neurobiology, Faculty of Medicine Hebrew, University of Jerusalem, Jerusalem, Israel
| | - Jihong Bai
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, United States of America
- * E-mail:
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15
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Woldemariam S, Nagpal J, Hill T, Li J, Schneider MW, Shankar R, Futey M, Varshney A, Ali N, Mitchell J, Andersen K, Barsi-Rhyne B, Tran A, Costa WS, Krzyzanowski MC, Yu YV, Brueggemann C, Hamilton OS, Ferkey DM, VanHoven M, Sengupta P, Gottschalk A, L'Etoile N. Using a Robust and Sensitive GFP-Based cGMP Sensor for Real-Time Imaging in Intact Caenorhabditis elegans. Genetics 2019; 213:59-77. [PMID: 31331946 PMCID: PMC6727795 DOI: 10.1534/genetics.119.302392] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/05/2019] [Indexed: 12/31/2022] Open
Abstract
cGMP plays a role in sensory signaling and plasticity by regulating ion channels, phosphodiesterases, and kinases. Studies that primarily used genetic and biochemical tools suggest that cGMP is spatiotemporally regulated in multiple sensory modalities. FRET- and GFP-based cGMP sensors were developed to visualize cGMP in primary cell culture and Caenorhabditis elegans to corroborate these findings. While a FRET-based sensor has been used in an intact animal to visualize cGMP, the requirement of a multiple emission system limits its ability to be used on its own as well as with other fluorophores. Here, we demonstrate that a C. elegans codon-optimized version of the cpEGFP-based cGMP sensor FlincG3 can be used to visualize rapidly changing cGMP levels in living, behaving C. elegans We coexpressed FlincG3 with the blue-light-activated guanylyl cyclases BeCyclOp and bPGC in body wall muscles, and found that the rate of change in FlincG3 fluorescence correlated with the rate of cGMP production by each cyclase. Furthermore, we show that FlincG3 responds to cultivation temperature, NaCl concentration changes, and sodium dodecyl sulfate in the sensory neurons AFD, ASEL/R, and PHB, respectively. Intriguingly, FlincG3 fluorescence in ASEL and ASER decreased in response to a NaCl concentration upstep and downstep, respectively, which is opposite in sign to the coexpressed calcium sensor jRGECO1a and previously published calcium recordings. These results illustrate that FlincG3 can be used to report rapidly changing cGMP levels in an intact animal, and that the reporter can potentially reveal unexpected spatiotemporal landscapes of cGMP in response to stimuli.
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Affiliation(s)
- Sarah Woldemariam
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, California 94158
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Jatin Nagpal
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Tyler Hill
- Neuroscience Graduate Program, Brandeis University, Waltham, Massachusetts 02453
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Joy Li
- Department of Biological Sciences, San Jose State University, California 95192
| | - Martin W Schneider
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Raakhee Shankar
- Department of Biological Sciences, San Jose State University, California 95192
| | - Mary Futey
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - Aruna Varshney
- Department of Biological Sciences, San Jose State University, California 95192
| | - Nebat Ali
- Department of Biological Sciences, San Jose State University, California 95192
| | - Jordan Mitchell
- Department of Biological Sciences, San Jose State University, California 95192
| | - Kristine Andersen
- Department of Biological Sciences, San Jose State University, California 95192
| | | | - Alan Tran
- Department of Biological Sciences, San Jose State University, California 95192
| | - Wagner Steuer Costa
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Michelle C Krzyzanowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Yanxun V Yu
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
| | - O Scott Hamilton
- Center for Neuroscience, University of California, Davis, California 95618
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, New York 14260
| | - Miri VanHoven
- Department of Biological Sciences, San Jose State University, California 95192
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454
| | - Alexander Gottschalk
- Department of Molecular Membrane Biology and Neurobiology, The Goethe University, 60323 Frankfurt, Germany
| | - Noelle L'Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143
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16
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Hoffman C, Aballay A. Role of neurons in the control of immune defense. Curr Opin Immunol 2019; 60:30-36. [PMID: 31117013 DOI: 10.1016/j.coi.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 11/28/2022]
Abstract
Studies in recent years have strengthened the notion that neural mechanisms are involved in the control of immune responses. From initial studies that highlighted the vagus nerve control of inflammatory responses in vertebrates, many advances have been made, including the dissection of specific neural circuits that are involved in controlling immunity. Part of this has been facilitated by the use of a tractable model animal, Caenorhabditis elegans, in which individual neurons involved in sensing pathogens and controlling the immune response have been identified. Importantly, some of the underlying mechanisms involved in the neural control of immune pathways appear to be present in evolutionarily diverse species. This review focuses on some major developments in vertebrates and C. elegans, and how these discoveries may lead to advances in understanding neural-immune connections that govern inflammatory responses.
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Affiliation(s)
- Casandra Hoffman
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States
| | - Alejandro Aballay
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States.
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17
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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: 1.9] [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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18
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Risley MG, Kelly SP, Minnerly J, Jia K, Dawson-Scully K. egl-4 modulates electroconvulsive seizure duration in C. elegans. INVERTEBRATE NEUROSCIENCE 2018; 18:8. [PMID: 29845318 DOI: 10.1007/s10158-018-0211-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/30/2018] [Indexed: 12/16/2022]
Abstract
Increased neuronal excitability causes seizures with debilitating symptoms. Effective and noninvasive treatments are limited for easing symptoms, partially due to the complexity of the disorder and lack of knowledge of specific molecular faults. An unexplored, novel target for seizure therapeutics is the cGMP/protein kinase G (PKG) pathway, which targets downstream K+ channels, a mechanism similar to Retigabine, a recently FDA-approved antiepileptic drug. Our results demonstrate that increased PKG activity decreased seizure duration in C. elegans utilizing a recently developed electroconvulsive seizure assay. While the fly is a well-established seizure model, C. elegans are an ideal yet unexploited model which easily uptakes drugs and can be utilized for high-throughput screens. In this study, we show that treating the worms with either a potassium channel opener, Retigabine or published pharmaceuticals that increase PKG activity, significantly reduces seizure recovery times. Our results suggest that PKG signaling modulates downstream K+ channel conductance to control seizure recovery time in C. elegans. Hence, we provide powerful evidence, suggesting that pharmacological manipulation of the PKG signaling cascade may control seizure duration across phyla.
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Affiliation(s)
- Monica G Risley
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Stephanie P Kelly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA. .,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA.
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19
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Co-nanoencapsulation of antimalarial drugs increases their in vitro efficacy against Plasmodium falciparum and decreases their toxicity to Caenorhabditis elegans. Eur J Pharm Sci 2018; 118:1-12. [PMID: 29550283 DOI: 10.1016/j.ejps.2018.03.014] [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] [Received: 11/24/2017] [Revised: 03/05/2018] [Accepted: 03/13/2018] [Indexed: 02/03/2023]
Abstract
Drugs used for the treatment and prevention of malaria have resistance-related problems, making them ineffective for monotherapy. If properly associated, many of these antimalarial drugs may find their way back to the treatment regimen. Among the therapeutic arsenal, quinine (QN) is a second-line treatment for uncomplicated malaria but has side effects that limit its use. Curcumin (CR) is a natural compound with anti-plasmodial activities and low bioavailability. In this context, the aim of this work was to develop and characterize co-encapsulated QN + CR-loaded polysorbate-coated polymeric nanocapsules (NC-QC) to evaluate their activity on Plasmodium falciparum and the safety of the nanoformulations for Caenorhabditis elegans. NC-QC displayed a diameter of approximately 200 nm, a negative zeta potential and a slightly basic pH. The drugs are homogeneously distributed in the NCs in the amorphous form. Co-encapsulated NCs exhibited a significant reduction in P. falciparum parasitemia, better than QN/CR. The worms exposed to NC-QC showed higher survival and longevity and no decrease in their reproductive capacity compared to free and associated drugs. It was possible to prove that the NCs were absorbed orally by the worms using fluorescence microscopy. Co-encapsulation of QN and CR was effective against P. falciparum, minimizing the toxic effects caused by chronic exposure of the free drugs in C. elegans.
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20
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Lautenschläger I, Wong YL, Sarau J, Goldmann T, Zitta K, Albrecht M, Frerichs I, Weiler N, Uhlig S. Signalling mechanisms in PAF-induced intestinal failure. Sci Rep 2017; 7:13382. [PMID: 29042668 PMCID: PMC5645457 DOI: 10.1038/s41598-017-13850-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/29/2017] [Indexed: 12/11/2022] Open
Abstract
Capillary leakage syndrome, vasomotor disturbances and gut atony are common clinical problems in intensive care medicine. Various inflammatory mediators and signalling pathways are involved in these pathophysiological alterations among them platelet-activating factor (PAF). The related signalling mechanisms of the PAF-induced dysfunctions are only poorly understood. Here we used the model of the isolated perfused rat small intestine to analyse the role of calcium (using calcium deprivation, IP-receptor blockade (2-APB)), cAMP (PDE-inhibition plus AC activator), myosin light chain kinase (inhibitor ML-7) and Rho-kinase (inhibitor Y27632) in the following PAF-induced malfunctions: vasoconstriction, capillary and mucosal leakage, oedema formation, malabsorption and atony. Among these, the PAF-induced vasoconstriction and hyperpermeability appear to be governed by similar mechanisms that involve IP3 receptors, extracellular calcium and the Rho-kinase. Our findings further suggest that cAMP-elevating treatments - while effective against hypertension and oedema - bear the risk of dysmotility and reduced nutrient uptake. Agents such as 2-APB or Y27632, on the other hand, showed no negative side effects and improved most of the PAF-induced malfunctions suggesting that their therapeutic usefulness should be explored.
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Affiliation(s)
- Ingmar Lautenschläger
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany.
| | - Yuk Lung Wong
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Jürgen Sarau
- Division of Mucosal Immunology and Diagnostic, Research Centre Borstel, Leibniz-Centre for Medicine and Biosciences, Borstel, Germany
| | - Torsten Goldmann
- Division of Clinical and Experimental Pathology, Research Centre Borstel, Leibniz-Centre for Medicine and Biosciences, Borstel, Germany
| | - Karina Zitta
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Martin Albrecht
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Norbert Weiler
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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21
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Tran A, Tang A, O'Loughlin CT, Balistreri A, Chang E, Coto Villa D, Li J, Varshney A, Jimenez V, Pyle J, Tsujimoto B, Wellbrook C, Vargas C, Duong A, Ali N, Matthews SY, Levinson S, Woldemariam S, Khuri S, Bremer M, Eggers DK, L'Etoile N, Miller Conrad LC, VanHoven MK. C. elegans avoids toxin-producing Streptomyces using a seven transmembrane domain chemosensory receptor. eLife 2017; 6. [PMID: 28873053 PMCID: PMC5584987 DOI: 10.7554/elife.23770] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 08/21/2017] [Indexed: 11/13/2022] Open
Abstract
Predators and prey co-evolve, each maximizing their own fitness, but the effects of predator–prey interactions on cellular and molecular machinery are poorly understood. Here, we study this process using the predator Caenorhabditis elegans and the bacterial prey Streptomyces, which have evolved a powerful defense: the production of nematicides. We demonstrate that upon exposure to Streptomyces at their head or tail, nematodes display an escape response that is mediated by bacterially produced cues. Avoidance requires a predicted G-protein-coupled receptor, SRB-6, which is expressed in five types of amphid and phasmid chemosensory neurons. We establish that species of Streptomyces secrete dodecanoic acid, which is sensed by SRB-6. This behavioral adaptation represents an important strategy for the nematode, which utilizes specialized sensory organs and a chemoreceptor that is tuned to recognize the bacteria. These findings provide a window into the molecules and organs used in the coevolutionary arms race between predator and potential prey.
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Affiliation(s)
- Alan Tran
- Department of Biological Sciences, San Jose State University, California, United States
| | - Angelina Tang
- Department of Biological Sciences, San Jose State University, California, United States
| | - Colleen T O'Loughlin
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, United States
| | - Anthony Balistreri
- Department of Chemistry, San Jose State University, California, United States
| | - Eric Chang
- Department of Biological Sciences, San Jose State University, California, United States
| | - Doris Coto Villa
- Department of Biological Sciences, San Jose State University, California, United States
| | - Joy Li
- Department of Biological Sciences, San Jose State University, California, United States
| | - Aruna Varshney
- Department of Biological Sciences, San Jose State University, California, United States
| | - Vanessa Jimenez
- Department of Biological Sciences, San Jose State University, California, United States
| | - Jacqueline Pyle
- Department of Biological Sciences, San Jose State University, California, United States
| | - Bryan Tsujimoto
- Department of Biological Sciences, San Jose State University, California, United States
| | - Christopher Wellbrook
- Department of Biological Sciences, San Jose State University, California, United States
| | - Christopher Vargas
- Department of Biological Sciences, San Jose State University, California, United States
| | - Alex Duong
- Department of Biological Sciences, San Jose State University, California, United States
| | - Nebat Ali
- Department of Biological Sciences, San Jose State University, California, United States
| | - Sarah Y Matthews
- Department of Chemistry, San Jose State University, California, United States
| | - Samantha Levinson
- Department of Chemistry, San Jose State University, California, United States
| | - Sarah Woldemariam
- Department of Cell & Tissue Biology, University of California San Francisco, San Francisco, United States
| | - Sami Khuri
- Department of Computer Science, San Jose State University, California, United States
| | - Martina Bremer
- Department of Mathematics and Statistics, San Jose State University, California, United States
| | - Daryl K Eggers
- Department of Chemistry, San Jose State University, California, United States
| | - Noelle L'Etoile
- Department of Cell & Tissue Biology, University of California San Francisco, San Francisco, United States
| | | | - Miri K VanHoven
- Department of Biological Sciences, San Jose State University, California, United States
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22
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Krzyzanowski MC, Woldemariam S, Wood JF, Chaubey AH, Brueggemann C, Bowitch A, Bethke M, L’Etoile ND, Ferkey DM. Aversive Behavior in the Nematode C. elegans Is Modulated by cGMP and a Neuronal Gap Junction Network. PLoS Genet 2016; 12:e1006153. [PMID: 27459302 PMCID: PMC4961389 DOI: 10.1371/journal.pgen.1006153] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 06/08/2016] [Indexed: 01/03/2023] Open
Abstract
All animals rely on their ability to sense and respond to their environment to survive. However, the suitability of a behavioral response is context-dependent, and must reflect both an animal's life history and its present internal state. Based on the integration of these variables, an animal's needs can be prioritized to optimize survival strategies. Nociceptive sensory systems detect harmful stimuli and allow for the initiation of protective behavioral responses. The polymodal ASH sensory neurons are the primary nociceptors in C. elegans. We show here that the guanylyl cyclase ODR-1 functions non-cell-autonomously to downregulate ASH-mediated aversive behaviors and that ectopic cGMP generation in ASH is sufficient to dampen ASH sensitivity. We define a gap junction neural network that regulates nociception and propose that decentralized regulation of ASH signaling can allow for rapid correlation between an animal's internal state and its behavioral output, lending modulatory flexibility to this hard-wired nociceptive neural circuit.
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Affiliation(s)
- Michelle C. Krzyzanowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Sarah Woldemariam
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Jordan F. Wood
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Aditi H. Chaubey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Alexander Bowitch
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Mary Bethke
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Noelle D. L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Denise M. Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
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23
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Reho JJ, Kenchegowda D, Asico LD, Fisher SA. A splice variant of the myosin phosphatase regulatory subunit tunes arterial reactivity and suppresses response to salt loading. Am J Physiol Heart Circ Physiol 2016; 310:H1715-24. [PMID: 27084390 DOI: 10.1152/ajpheart.00869.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/12/2016] [Indexed: 12/21/2022]
Abstract
The cGMP activated kinase cGK1α is targeted to its substrates via leucine zipper (LZ)-mediated heterodimerization and thereby mediates vascular smooth muscle (VSM) relaxation. One target is myosin phosphatase (MP), which when activated by cGK1α results in VSM relaxation even in the presence of activating calcium. Variants of MP regulatory subunit Mypt1 are generated by alternative splicing of the 31 nt exon 24 (E24), which, by changing the reading frame, codes for isoforms that contain or lack the COOH-terminal LZ motif (E24+/LZ-; E24-/LZ+). Expression of these isoforms is vessel specific and developmentally regulated, modulates in disease, and is proposed to confer sensitivity to nitric oxide (NO)/cGMP-mediated vasorelaxation. To test this, mice underwent Tamoxifen-inducible and smooth muscle-specific knockout of E24 (E24 cKO) after weaning. Deletion of a single allele of E24 (shift to Mypt1 LZ+) enhanced vasorelaxation of first-order mesenteric arteries (MA1) to diethylamine-NONOate (DEA/NO) and to cGMP in permeabilized and calcium-clamped arteries and lowered blood pressure. There was no further effect of deletion of both E24 alleles, indicating high sensitivity to shift of Mypt1 isoforms. However, a unique property of MA1s from homozygous E24 cKOs was significantly reduced force generation to α-adrenergic activation. Furthermore 2 wk of high-salt (4% NaCl) diet increased MA1 force generation to phenylephrine in control mice, a response that was markedly suppressed in the E24 cKO homozygotes. Thus Mypt1 E24 splice variants tune arterial reactivity and could be worthy targets for lowering vascular resistance in disease states.
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Affiliation(s)
- John J Reho
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Doreswamy Kenchegowda
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Laureano D Asico
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Steven A Fisher
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
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Larsch J, Flavell SW, Liu Q, Gordus A, Albrecht DR, Bargmann CI. A Circuit for Gradient Climbing in C. elegans Chemotaxis. Cell Rep 2015; 12:1748-60. [PMID: 26365196 PMCID: PMC5045890 DOI: 10.1016/j.celrep.2015.08.032] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/20/2015] [Accepted: 08/07/2015] [Indexed: 12/12/2022] Open
Abstract
Animals have a remarkable ability to track dynamic sensory information. For example, the nematode Caenorhabditis elegans can locate a diacetyl odor source across a 100,000-fold concentration range. Here, we relate neuronal properties, circuit implementation, and behavioral strategies underlying this robust navigation. Diacetyl responses in AWA olfactory neurons are concentration and history dependent; AWA integrates over time at low odor concentrations, but as concentrations rise, it desensitizes rapidly through a process requiring cilia transport. After desensitization, AWA retains sensitivity to small odor increases. The downstream AIA interneuron amplifies weak odor inputs and desensitizes further, resulting in a stereotyped response to odor increases over three orders of magnitude. The AWA-AIA circuit drives asymmetric behavioral responses to odor increases that facilitate gradient climbing. The adaptation-based circuit motif embodied by AWA and AIA shares computational properties with bacterial chemotaxis and the vertebrate retina, each providing a solution for maintaining sensitivity across a dynamic range.
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Affiliation(s)
- Johannes Larsch
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Steven W Flavell
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Qiang Liu
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Andrew Gordus
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Dirk R Albrecht
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Cornelia I Bargmann
- Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY 10065, USA.
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Zahratka JA, Williams PDE, Summers PJ, Komuniecki RW, Bamber BA. Serotonin differentially modulates Ca2+ transients and depolarization in a C. elegans nociceptor. J Neurophysiol 2014; 113:1041-50. [PMID: 25411461 DOI: 10.1152/jn.00665.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Monoamines and neuropeptides modulate neuronal excitability and synaptic strengths, shaping circuit activity to optimize behavioral output. In C. elegans, a pair of bipolar polymodal nociceptors, the ASHs, sense 1-octanol to initiate escape responses. In the present study, 1-octanol stimulated large increases in ASH Ca(2+), mediated by L-type voltage-gated Ca(2+) channels (VGCCs) in the cell soma and L-plus P/Q-type VGCCs in the axon, which were further amplified by Ca(2+) released from intracellular stores. Importantly, 1-octanol-dependent aversive responses were not inhibited by reducing ASH L-VGCC activity genetically or pharmacologically. Serotonin, an enhancer of 1-octanol avoidance, potentiated 1-octanol-dependent ASH depolarization measured electrophysiologically, but surprisingly, decreased the ASH somal Ca(2+) transients. These results suggest that ASH somal Ca(2+) transient amplitudes may not always be predictive of neuronal depolarization and synaptic output. Therefore, although increases in steady-state Ca(2+) can reliably indicate when neurons become active, quantitative relationships between Ca(2+) transient amplitudes and neuronal activity may not be as straightforward as previously anticipated.
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Affiliation(s)
- Jeffrey A Zahratka
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | - Paul D E Williams
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | - Philip J Summers
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
| | | | - Bruce A Bamber
- Department of Biological Sciences, The University of Toledo, Toledo, Ohio
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