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Chen L, Su P, Wang Y, Liu Y, Chen LM, Gao S. CKR-1 orchestrates two motor states from a single motoneuron in C. elegans. iScience 2024; 27:109390. [PMID: 38510145 PMCID: PMC10952047 DOI: 10.1016/j.isci.2024.109390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/22/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Neuromodulation is pivotal in modifying neuronal properties and motor states. CKR-1, a homolog of the cholecystokinin receptor, modulates robust escape steering and undulation body bending in C. elegans. Nevertheless, the mechanisms through which CKR-1 governs these motor states remain elusive. We elucidate the head motoneuron SMD as the orchestrator of both motor states. This regulation involves two neuropeptides: NLP-12 from DVA enhances undulation body curvature, while NLP-18 from ASI amplifies Ω-turn head curvature. Moreover, synthetic NLP-12 and NLP-18 peptides elicit CKR-1-dependent currents in Xenopus oocytes and Ca2+ transients in SMD neurons. Notably, CKR-1 shows higher sensitivity to NLP-18 compared to NLP-12. In situ patch-clamp recordings reveal CKR-1, NLP-12, and NLP-18 are not essential for neurotransmission at C. elegans neuromuscular junction, suggesting that SMD independently regulates head and body bending. Our studies illustrate that a single motoneuron SMD utilizes a cholecystokinin receptor CKR-1 to integrate two motor states.
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Affiliation(s)
- Lili Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Pan Su
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ya Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuting Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Li-Ming Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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2
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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: 5] [Impact Index Per Article: 5.0] [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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3
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Beets I, Zels S, Vandewyer E, Demeulemeester J, Caers J, Baytemur E, Courtney A, Golinelli L, Hasakioğulları İ, Schafer WR, Vértes PE, Mirabeau O, Schoofs L. System-wide mapping of peptide-GPCR interactions in C. elegans. Cell Rep 2023; 42:113058. [PMID: 37656621 PMCID: PMC7615250 DOI: 10.1016/j.celrep.2023.113058] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 07/19/2023] [Accepted: 08/16/2023] [Indexed: 09/03/2023] Open
Abstract
Neuropeptides and peptide hormones are ancient, widespread signaling molecules that underpin almost all brain functions. They constitute a broad ligand-receptor network, mainly by binding to G protein-coupled receptors (GPCRs). However, the organization of the peptidergic network and roles of many peptides remain elusive, as our insight into peptide-receptor interactions is limited and many peptide GPCRs are still orphan receptors. Here we report a genome-wide peptide-GPCR interaction map in Caenorhabditis elegans. By reverse pharmacology screening of over 55,384 possible interactions, we identify 461 cognate peptide-GPCR couples that uncover a broad signaling network with specific and complex combinatorial interactions encoded across and within single peptidergic genes. These interactions provide insights into peptide functions and evolution. Combining our dataset with phylogenetic analysis supports peptide-receptor co-evolution and conservation of at least 14 bilaterian peptidergic systems in C. elegans. This resource lays a foundation for system-wide analysis of the peptidergic network.
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Affiliation(s)
- Isabel Beets
- Department of Biology, KU Leuven, 3000 Leuven, Belgium.
| | - Sven Zels
- Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | | | - Jonas Demeulemeester
- The Francis Crick Institute, London NW1 1AT, UK; VIB - KU Leuven Center for Cancer Biology, 3000 Leuven, Belgium; Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Jelle Caers
- Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Esra Baytemur
- Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Amy Courtney
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | | | | | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Petra E Vértes
- Department of Psychiatry, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
| | - Olivier Mirabeau
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Inserm U1224, Brain-Immune Communication Lab, 75015 Paris, France
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4
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Choi U, Hu M, Zhang Q, Sieburth D. The head mesodermal cell couples FMRFamide neuropeptide signaling with rhythmic muscle contraction in C. elegans. Nat Commun 2023; 14:4218. [PMID: 37452027 PMCID: PMC10349088 DOI: 10.1038/s41467-023-39955-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
FMRFamides are evolutionarily conserved neuropeptides that play critical roles in behavior, energy balance, and reproduction. Here, we show that FMRFamide signaling from the nervous system is critical for the rhythmic activation of a single cell of previously unknown function, the head mesodermal cell (hmc) in C. elegans. Behavioral, calcium imaging, and genetic studies reveal that release of the FLP-22 neuropeptide from the AVL neuron in response to pacemaker signaling activates hmc every 50 s through an frpr-17 G protein-coupled receptor (GPCR) and a protein kinase A signaling cascade in hmc. hmc activation results in muscle contraction through coupling by gap junctions composed of UNC-9/Innexin. hmc activation is inhibited by the neuronal release of a second FMRFamide-like neuropeptide, FLP-9, which functions through its GPCR, frpr-21, in hmc. This study reveals a function for two opposing FMRFamide signaling pathways in controlling the rhythmic activation of a target cell through volume transmission.
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Affiliation(s)
- Ukjin Choi
- DSR graduate program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Mingxi Hu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Qixin Zhang
- MPHY program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, 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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Liu H, Wu JJ, Li R, Wang PZ, Huang JH, Xu Y, Zhao JL, Wu PP, Li SJ, Wu ZX. Disexcitation in the ASH/RIM/ADL negative feedback circuit fine-tunes hyperosmotic sensation and avoidance in Caenorhabditis elegans. Front Mol Neurosci 2023; 16:1101628. [PMID: 37008778 PMCID: PMC10050701 DOI: 10.3389/fnmol.2023.1101628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/21/2023] [Indexed: 03/17/2023] Open
Abstract
Sensations, especially nociception, are tightly controlled and regulated by the central and peripheral nervous systems. Osmotic sensation and related physiological and behavioral reactions are essential for animal well-being and survival. In this study, we find that interaction between secondary nociceptive ADL and primary nociceptive ASH neurons upregulates Caenorhabditis elegans avoidance of the mild and medium hyperosmolality of 0.41 and 0.88 Osm but does not affect avoidance of high osmolality of 1.37 and 2.29 Osm. The interaction between ASH and ADL is actualized through a negative feedback circuit consisting of ASH, ADL, and RIM interneurons. In this circuit, hyperosmolality-sensitive ADL augments the ASH hyperosmotic response and animal hyperosmotic avoidance; RIM inhibits ADL and is excited by ASH; thus, ASH exciting RIM reduces ADL augmenting ASH. The neuronal signal integration modality in the circuit is disexcitation. In addition, ASH promotes hyperosmotic avoidance through ASH/RIC/AIY feedforward circuit. Finally, we find that in addition to ASH and ADL, multiple sensory neurons are involved in hyperosmotic sensation and avoidance behavior.
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7
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Neuropeptide diuretic hormone 31 mediates memory and sleep via distinct neural pathways in Drosophila. Neurosci Res 2023:S0168-0102(23)00037-8. [PMID: 36780946 DOI: 10.1016/j.neures.2023.02.003] [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: 11/30/2022] [Revised: 01/29/2023] [Accepted: 02/07/2023] [Indexed: 02/13/2023]
Abstract
Memory formation and sleep regulation are critical for brain functions in animals from invertebrates to humans. Neuropeptides play a pivotal role in regulating physiological behaviors, including memory formation and sleep. However, the detailed mechanisms by which neuropeptides regulate these physiological behaviors remains unclear. Herein, we report that neuropeptide diuretic hormone 31 (DH31) positively regulates memory formation and sleep in Drosophila melanogaster. The expression of DH31 in the dorsal and ventral fan-shaped body (dFB and vFB) neurons of the central complex and ventral lateral clock neurons (LNvs) in the brain was responsive to sleep regulation. In addition, the expression of membrane-tethered DH31 in dFB neurons rescued sleep defects in Dh31 mutants, suggesting that DH31 secreted from dFB, vFB, and LNvs acts on the DH31 receptor in the dFB to regulate sleep partly in an autoregulatory feedback loop. Moreover, the expression of DH31 in octopaminergic neurons, but not in the dFB neurons, is involved in forming intermediate-term memory. Our results suggest that DH31 regulates memory formation and sleep through distinct neural pathways.
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8
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Preusser F, Neuschulz A, Junker JP, Rajewsky N, Preibisch S. Long-term imaging reveals behavioral plasticity during C. elegans dauer exit. BMC Biol 2022; 20:277. [PMID: 36514066 DOI: 10.1186/s12915-022-01471-4] [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: 06/16/2022] [Accepted: 11/18/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND During their lifetime, animals must adapt their behavior to survive in changing environments. This ability requires the nervous system to undergo adjustments at distinct temporal scales, from short-term dynamic changes in expression of neurotransmitters and receptors to longer-term growth, spatial and connectivity reorganization, while integrating external stimuli. The nematode Caenorhabditis elegans provides a model of nervous system plasticity, in particular its dauer exit decision. Under unfavorable conditions, larvae will enter the non-feeding and non-reproductive stress-resistant dauer stage and adapt their behavior to cope with the harsh new environment, with active reversal under improved conditions leading to resumption of reproductive development. However, how different environmental stimuli regulate the exit decision mechanism and thereby drive the larva's behavioral change is unknown. To fill this gap and provide insights on behavioral changes over extended periods of time, we developed a new open hardware method for long-term imaging (12h) of C. elegans larvae. RESULTS Our WormObserver platform comprises open hardware and software components for video acquisition, automated processing of large image data (> 80k images/experiment) and data analysis. We identified dauer-specific behavioral motifs and characterized the behavioral trajectory of dauer exit in different environments and genetic backgrounds to identify key decision points and stimuli promoting dauer exit. Combining long-term behavioral imaging with transcriptomics data, we find that bacterial ingestion triggers a change in neuropeptide gene expression to establish post-dauer behavior. CONCLUSIONS Taken together, we show how a developing nervous system can robustly integrate environmental changes activate a developmental switch and adapt the organism's behavior to a new environment. WormObserver is generally applicable to other research questions within and beyond the C. elegans field, having a modular and customizable character and allowing assessment of behavioral plasticity over longer periods.
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Affiliation(s)
- Friedrich Preusser
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany. .,Institute for Biology, Humboldt University of Berlin, 10099, Berlin, Germany.
| | - Anika Neuschulz
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany.,Institute for Biology, Humboldt University of Berlin, 10099, Berlin, Germany
| | - Jan Philipp Junker
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany
| | - Nikolaus Rajewsky
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany
| | - Stephan Preibisch
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA.
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9
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Geng S, Li Q, Zhou X, Zheng J, Liu H, Zeng J, Yang R, Fu H, Hao F, Feng Q, Qi B. Gut commensal E. coli outer membrane proteins activate the host food digestive system through neural-immune communication. Cell Host Microbe 2022; 30:1401-1416.e8. [PMID: 36057258 DOI: 10.1016/j.chom.2022.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/01/2022] [Accepted: 08/05/2022] [Indexed: 12/13/2022]
Abstract
The gastrointestinal tract facilitates food digestion, with the gut microbiota playing pivotal roles in nutrient breakdown and absorption. However, the microbial molecules and downstream signaling pathways that activate food digestion remain unexplored. Here, by establishing a food digestion system in C. elegans, we discover that food breakdown is regulated by the interaction between bacterial outer membrane proteins (OMPs) and a neural-immune pathway. E. coli OmpF/A activate digestion by increasing the neuropeptide NLP-12 that acts on the receptor CCKR. NLP-12 is homologous to mammalian cholecystokinin, known to stimulate dopamine, and we found that loss of dopamine receptors or addition of a dopamine antagonist inhibited OMP-mediated digestion. Dopamine and NLP-12-CKR-1 converge to inhibit PMK-1/p38 innate immune signaling. Moreover, directly inhibiting PMK-1/p38 boosts food digestion. This study uncovers a role of bacterial OMPs in regulating animal nutrient uptake and supports a key role for innate immunity in digestion.
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Affiliation(s)
- Shengya Geng
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Qian Li
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Xue Zhou
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Junkang Zheng
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Huimin Liu
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Jie Zeng
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Ruizhi Yang
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Herui Fu
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Fanrui Hao
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Qianxu Feng
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China
| | - Bin Qi
- Center for Life Sciences, School of Life Sciences, State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650500, China.
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10
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Yu YV, Xue W, Chen Y. Multisensory Integration in Caenorhabditis elegans in Comparison to Mammals. Brain Sci 2022; 12:brainsci12101368. [PMID: 36291302 PMCID: PMC9599712 DOI: 10.3390/brainsci12101368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 11/30/2022] Open
Abstract
Multisensory integration refers to sensory inputs from different sensory modalities being processed simultaneously to produce a unitary output. Surrounded by stimuli from multiple modalities, animals utilize multisensory integration to form a coherent and robust representation of the complex environment. Even though multisensory integration is fundamentally essential for animal life, our understanding of the underlying mechanisms, especially at the molecular, synaptic and circuit levels, remains poorly understood. The study of sensory perception in Caenorhabditis elegans has begun to fill this gap. We have gained a considerable amount of insight into the general principles of sensory neurobiology owing to C. elegans’ highly sensitive perceptions, relatively simple nervous system, ample genetic tools and completely mapped neural connectome. Many interesting paradigms of multisensory integration have been characterized in C. elegans, for which input convergence occurs at the sensory neuron or the interneuron level. In this narrative review, we describe some representative cases of multisensory integration in C. elegans, summarize the underlying mechanisms and compare them with those in mammalian systems. Despite the differences, we believe C. elegans is able to provide unique insights into how processing and integrating multisensory inputs can generate flexible and adaptive behaviors. With the emergence of whole brain imaging, the ability of C. elegans to monitor nearly the entire nervous system may be crucial for understanding the function of the brain as a whole.
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Affiliation(s)
- Yanxun V. Yu
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
- Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430070, China
- Correspondence: or
| | - Weikang Xue
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
| | - Yuanhua Chen
- Department of Neurology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430070, China
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11
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Luxmi R, King SM. Cilia-derived vesicles: An ancient route for intercellular communication. Semin Cell Dev Biol 2022; 129:82-92. [PMID: 35346578 PMCID: PMC9378432 DOI: 10.1016/j.semcdb.2022.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 12/11/2022]
Abstract
Extracellular vesicles (EVs) provide a mechanism for intercellular communication that transports complex signals in membrane delimited structures between cells, tissues and organisms. Cells secrete EVs of various subtypes defined by the pathway leading to release and by the pathological condition of the cell. Cilia are evolutionarily conserved organelles that can act as sensory structures surveilling the extracellular environment. Here we discuss the secretory functions of cilia and their biological implications. Studies in multiple species - from the nematode Caenorhabditis elegans and the chlorophyte alga Chlamydomonas reinhardtii to mammals - have revealed that cilia shed bioactive EVs (ciliary EVs or ectosomes) by outward budding of the ciliary membrane. The content of ciliary EVs is distinct from that of other vesicles released by cells. Peptides regulate numerous aspects of metazoan physiology and development through evolutionarily conserved mechanisms. Intriguingly, cilia-derived vesicles have recently been found to mediate peptidergic signaling. C. reinhardtii releases the peptide α-amidating enzyme (PAM), bioactive amidated products and components of the peptidergic signaling machinery in ciliary EVs in a developmentally regulated manner. Considering the origin of cilia in early eukaryotes, it is likely that release of peptidergic signals in ciliary EVs represents an alternative and ancient mode of regulated secretion that cells can utilize in the absence of dedicated secretory granules.
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Affiliation(s)
- Raj Luxmi
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
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12
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Potentials of Neuropeptides as Therapeutic Agents for Neurological Diseases. Biomedicines 2022; 10:biomedicines10020343. [PMID: 35203552 PMCID: PMC8961788 DOI: 10.3390/biomedicines10020343] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 02/04/2023] Open
Abstract
Despite recent leaps in modern medicine, progress in the treatment of neurological diseases remains slow. The near impermeable blood-brain barrier (BBB) that prevents the entry of therapeutics into the brain, and the complexity of neurological processes, limits the specificity of potential therapeutics. Moreover, a lack of etiological understanding and the irreversible nature of neurological conditions have resulted in low tolerability and high failure rates towards existing small molecule-based treatments. Neuropeptides, which are small proteinaceous molecules produced by the body, either in the nervous system or the peripheral organs, modulate neurological function. Although peptide-based therapeutics originated from the treatment of metabolic diseases in the 1920s, the adoption and development of peptide drugs for neurological conditions are relatively recent. In this review, we examine the natural roles of neuropeptides in the modulation of neurological function and the development of neurological disorders. Furthermore, we highlight the potential of these proteinaceous molecules in filling gaps in current therapeutics.
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