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Ndjim M, Gasmi I, Herbert F, Joséphine C, Bas J, Lamrani A, Coutry N, Henry S, Zimmermann VS, Dardalhon V, Campillo Poveda M, Turtoi E, Thirard S, Forichon L, Giordano A, Ciancia C, Homayed Z, Pannequin J, Britton C, Devaney E, McNeilly TN, Berrard S, Turtoi A, Maizels RM, Gerbe F, Jay P. Tuft cell acetylcholine is released into the gut lumen to promote anti-helminth immunity. Immunity 2024; 57:1260-1273.e7. [PMID: 38744292 DOI: 10.1016/j.immuni.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 11/26/2023] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
Upon parasitic helminth infection, activated intestinal tuft cells secrete interleukin-25 (IL-25), which initiates a type 2 immune response during which lamina propria type 2 innate lymphoid cells (ILC2s) produce IL-13. This causes epithelial remodeling, including tuft cell hyperplasia, the function of which is unknown. We identified a cholinergic effector function of tuft cells, which are the only epithelial cells that expressed choline acetyltransferase (ChAT). During parasite infection, mice with epithelial-specific deletion of ChAT had increased worm burden, fitness, and fecal egg counts, even though type 2 immune responses were comparable. Mechanistically, IL-13-amplified tuft cells release acetylcholine (ACh) into the gut lumen. Finally, we demonstrated a direct effect of ACh on worms, which reduced their fecundity via helminth-expressed muscarinic ACh receptors. Thus, tuft cells are sentinels in naive mice, and their amplification upon helminth infection provides an additional type 2 immune response effector function.
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Affiliation(s)
- Marième Ndjim
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Imène Gasmi
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Fabien Herbert
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Charlène Joséphine
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Julie Bas
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Ali Lamrani
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Nathalie Coutry
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Sylvain Henry
- Montpellier Alliance for Metabolomics and Metabolism Analysis, Platform for Translational Oncometabolomics (PLATON), Biocampus, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Valérie S Zimmermann
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Valérie Dardalhon
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Marta Campillo Poveda
- Centre for Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, UK
| | - Evgenia Turtoi
- Montpellier Alliance for Metabolomics and Metabolism Analysis, Platform for Translational Oncometabolomics (PLATON), Biocampus, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Steeve Thirard
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Luc Forichon
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Alicia Giordano
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Claire Ciancia
- Centre for Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, UK
| | - Zeinab Homayed
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Julie Pannequin
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France
| | - Collette Britton
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Eileen Devaney
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Tom N McNeilly
- Disease Control Department, Moredun Research Institute, Penicuik, UK
| | - Sylvie Berrard
- University Paris Cité, Inserm, NeuroDiderot, Paris, France
| | - Andrei Turtoi
- Montpellier Alliance for Metabolomics and Metabolism Analysis, Platform for Translational Oncometabolomics (PLATON), Biocampus, CNRS, INSERM, Université de Montpellier, Montpellier, France; Cancer Research Institute of Montpellier (IRCM), University of Montpellier, Inserm, Montpellier, France
| | - Rick M Maizels
- Centre for Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, UK
| | - François Gerbe
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France.
| | - Philippe Jay
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, Inserm, Montpellier, France.
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Li L, Li Y, Zeng K, Wang Q. Mercuric sulfide nanoparticles suppress the neurobehavioral functions of Caenorhabditis elegans through a Skp1-dependent mechanism. Food Chem Toxicol 2024; 186:114576. [PMID: 38458533 DOI: 10.1016/j.fct.2024.114576] [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: 11/27/2023] [Revised: 02/11/2024] [Accepted: 03/05/2024] [Indexed: 03/10/2024]
Abstract
Cinnabar is the naturally occurring mercuric sulfide (HgS) and concerns about its safety have been grown. However, the molecular mechanism of HgS-related neurotoxicity remains unclear. S-phase kinase-associated protein 1 (Skp1), identified as the target protein of HgS, plays a crucial role in the development of neurological diseases. This study aims to investigate the neurotoxic effects and molecular mechanism of HgS based on Skp1 using the Caenorhabditis elegans (C. elegans) model. We prepared the HgS nanoparticles and conducted a comparative analysis of neurobehavioral differences in both wild-type C. elegans (N2) and a transgenic strain of C. elegans (VC1241) with a knockout of the SKP1 homologous gene after exposure to HgS nanoparticles. Our results showed that HgS nanoparticles could suppress locomotion, defecation, egg-laying, and associative learning behaviors in N2 C. elegans, while no significant alterations were observed in the VC1241 C. elegans. Furthermore, we conducted a 4D label-free proteomics analysis and screened 504 key proteins significantly affected by HgS nanoparticles through Skp1. These proteins play pivotal roles in various pathways, including SNARE interactions in vesicular transport, TGF-beta signaling pathway, calcium signaling pathway, FoxO signaling pathway, etc. In summary, HgS nanoparticles at high doses suppress the neurobehavioral functions of C. elegans through a Skp1-dependent mechanism.
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Affiliation(s)
- Ludi Li
- Department of Toxicology, School of Public Health, Peking University, Beijing, 100191, China.
| | - Yingzi Li
- Department of Toxicology, School of Public Health, Peking University, Beijing, 100191, China.
| | - Kewu Zeng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China.
| | - Qi Wang
- Department of Toxicology, School of Public Health, Peking University, Beijing, 100191, China; Key Laboratory of State Administration of Traditional Chinese Medicine for Compatibility Toxicology, Beijing, 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing, 100191, China.
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Ngo LT, Huang WT, Chan MH, Su TY, Li CH, Hsiao M, Liu RS. Comprehensive Neurotoxicity of Lead Halide Perovskite Nanocrystals in Nematode Caenorhabditis elegans. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306020. [PMID: 37661358 DOI: 10.1002/smll.202306020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 09/05/2023]
Abstract
To date, all-inorganic lead halide perovskite quantum dots have emerged as promising materials for photonic, optoelectronic devices, and biological applications, especially in solar cells, raising numerous concerns about their biosafety. Most of the studies related to the toxicity of perovskite quantum dots (PeQDs) have focused on the potential risks of hybrid perovskites by using zebrafish or human cells. So far, the neurotoxic effects and fundamental mechanisms of PeQDs remain unknown. Herein, a comprehensive methodology is designed to investigate the neurotoxicity of PeQDs by using Caenorhabditis elegans as a model organism. The results show that the accumulation of PeQDs mainly focuses on the alimentary system and head region. Acute exposure to PeQDs results in a decrease in locomotor behaviors and pharyngeal pumping, whereas chronic exposure to PeQDs causes brood decline and shortens lifespan. In addition, some abnormal issues occur in the uterus during reproduction assays, such as vulva protrusion, impaired eggs left in the vulva, and egg hatching inside the mother. Excessive reactive oxygen species formation is also observed. The neurotoxicity of PeQDs is explained by gene expression. This study provides a complete insight into the neurotoxicity of PeQD and encourages the development of novel nontoxic PeQDs.
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Affiliation(s)
- Loan Thi Ngo
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
- Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan University, Academia Road 128, Nankang, Taipei, 115, Taiwan
| | - Wen-Tse Huang
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Ming-Hsien Chan
- Genomics Research Center, Academia Sinica, Academia Road 128, Nankang, Taipei, 115, Taiwan
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan
| | - Ting-Yi Su
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Chien-Hsiu Li
- Genomics Research Center, Academia Sinica, Academia Road 128, Nankang, Taipei, 115, Taiwan
| | - Michael Hsiao
- Genomics Research Center, Academia Sinica, Academia Road 128, Nankang, Taipei, 115, Taiwan
| | - Ru-Shi Liu
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
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Prakash SJ, Van Auken KM, Hill DP, Sternberg PW. Semantic representation of neural circuit knowledge in Caenorhabditis elegans. Brain Inform 2023; 10:30. [PMID: 37947958 PMCID: PMC10638142 DOI: 10.1186/s40708-023-00208-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/22/2023] [Indexed: 11/12/2023] Open
Abstract
In modern biology, new knowledge is generated quickly, making it challenging for researchers to efficiently acquire and synthesise new information from the large volume of primary publications. To address this problem, computational approaches that generate machine-readable representations of scientific findings in the form of knowledge graphs have been developed. These representations can integrate different types of experimental data from multiple papers and biological knowledge bases in a unifying data model, providing a complementary method to manual review for interacting with published knowledge. The Gene Ontology Consortium (GOC) has created a semantic modelling framework that extends individual functional gene annotations to structured descriptions of causal networks representing biological processes (Gene Ontology-Causal Activity Modelling, or GO-CAM). In this study, we explored whether the GO-CAM framework could represent knowledge of the causal relationships between environmental inputs, neural circuits and behavior in the model nematode C. elegans [C. elegans Neural-Circuit Causal Activity Modelling (CeN-CAM)]. We found that, given extensions to several relevant ontologies, a wide variety of author statements from the literature about the neural circuit basis of egg-laying and carbon dioxide (CO2) avoidance behaviors could be faithfully represented with CeN-CAM. Through this process, we were able to generate generic data models for several categories of experimental results. We also discuss how semantic modelling may be used to functionally annotate the C. elegans connectome. Thus, Gene Ontology-based semantic modelling has the potential to support various machine-readable representations of neurobiological knowledge.
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Affiliation(s)
- Sharan J Prakash
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Kimberly M Van Auken
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - David P Hill
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
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Medrano E, Collins KM. Muscle-directed mechanosensory feedback activates egg-laying circuit activity and behavior in Caenorhabditis elegans. Curr Biol 2023; 33:2330-2339.e8. [PMID: 37236183 PMCID: PMC10280788 DOI: 10.1016/j.cub.2023.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/29/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023]
Abstract
Mechanosensory feedback of the internal reproductive state drives decisions about when and where to reproduce.1 For instance, stretch in the Drosophila reproductive tract produced by artificial distention or from accumulated eggs regulates the attraction to acetic acid to ensure optimal oviposition.2 How such mechanosensory feedback modulates neural circuits to coordinate reproductive behaviors is incompletely understood. We previously identified a stretch-dependent homeostat that regulates egg laying in Caenorhabditis elegans. Sterilized animals lacking eggs show reduced Ca2+ transient activity in the presynaptic HSN command motoneurons that drive egg-laying behavior, while animals forced to accumulate extra eggs show dramatically increased circuit activity that restores egg laying.3 Interestingly, genetic ablation or electrical silencing of the HSNs delays, but does not abolish, the onset of egg laying,3,4,5 with animals recovering vulval muscle Ca2+ transient activity upon egg accumulation.6 Using an acute gonad microinjection technique to mimic changes in pressure and stretch resulting from germline activity and egg accumulation, we find that injection rapidly stimulates Ca2+ activity in both neurons and muscles of the egg-laying circuit. Injection-induced vulval muscle Ca2+ activity requires L-type Ca2+ channels but is independent of presynaptic input. Conversely, injection-induced neural activity is disrupted in mutants lacking the vulval muscles, suggesting "bottom-up" feedback from muscles to neurons. Direct mechanical prodding activates the vulval muscles, suggesting that they are the proximal targets of the stretch-dependent stimulus. Our results show that egg-laying behavior in C. elegans is regulated by a stretch-dependent homeostat that scales postsynaptic muscle responses with egg accumulation in the uterus.
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Affiliation(s)
- Emmanuel Medrano
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA
| | - Kevin M Collins
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA.
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6
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Olson AC, Butt AM, Christie NTM, Shelar A, Koelle MR. Multiple Subthreshold GPCR Signals Combined by the G-Proteins Gα q and Gα s Activate the Caenorhabditis elegans Egg-Laying Muscles. J Neurosci 2023; 43:3789-3806. [PMID: 37055179 PMCID: PMC10219013 DOI: 10.1523/jneurosci.2301-22.2023] [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: 12/14/2022] [Revised: 03/21/2023] [Accepted: 04/07/2023] [Indexed: 04/15/2023] Open
Abstract
Individual neurons or muscle cells express many G-protein-coupled receptors (GPCRs) for neurotransmitters and neuropeptides, yet it remains unclear how cells integrate multiple GPCR signals that all must activate the same few G-proteins. We analyzed this issue in the Caenorhabditis elegans egg-laying system, where multiple GPCRs on muscle cells promote contraction and egg laying. We genetically manipulated individual GPCRs and G-proteins specifically in these muscle cells within intact animals and then measured egg laying and muscle calcium activity. Two serotonin GPCRs on the muscle cells, Gαq-coupled SER-1 and Gαs-coupled SER-7, together promote egg laying in response to serotonin. We found that signals produced by either SER-1/Gαq or SER-7/Gαs alone have little effect, but these two subthreshold signals combine to activate egg laying. We then transgenically expressed natural or designer GPCRs in the muscle cells and found that their subthreshold signals can also combine to induce muscle activity. However, artificially inducing strong signaling through just one of these GPCRs can be sufficient to induce egg laying. Knocking down Gαq and Gαs in the egg-laying muscle cells induced egg-laying defects that were stronger than those of a SER-1/SER-7 double knockout, indicating that additional endogenous GPCRs also activate the muscle cells. These results show that in the egg-laying muscles multiple GPCRs for serotonin and other signals each produce weak effects that individually do not result in strong behavioral outcomes. However, they combine to produce sufficient levels of Gαq and Gαs signaling to promote muscle activity and egg laying.SIGNIFICANCE STATEMENT How can neurons and other cells gather multiple independent pieces of information from the soup of chemical signals in their environment and compute an appropriate response? Most cells express >20 GPCRs that each receive one signal and transmit that information through three main types of G-proteins. We analyzed how this machinery generates responses by studying the egg-laying system of C. elegans, where serotonin and multiple other signals act through GPCRs on the egg-laying muscles to promote muscle activity and egg laying. We found that individual GPCRs within an intact animal each generate effects too weak to activate egg laying. However, combined signaling from multiple GPCR types reaches a threshold capable of activating the muscle cells.
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Affiliation(s)
- Andrew C Olson
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Allison M Butt
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Nakeirah T M Christie
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Ashish Shelar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
| | - Michael R Koelle
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510
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Liu X, Ge P, Lu Z, Yang R, Liu Z, Zhao F, Chen M. Reproductive toxicity and underlying mechanisms of fine particulate matter (PM 2.5) on Caenorhabditis elegans in different seasons. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 248:114281. [PMID: 36379073 DOI: 10.1016/j.ecoenv.2022.114281] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Although numerous studies have investigated that atmospheric fine particulate matter (PM2.5) can be toxic to environmental organisms, the research on the reproductive toxicity of PM2.5 is limited, and the key toxic components and underlying mechanisms remain unknown. In this work, PM2.5 samples of four seasons in Nanjing from March 1, 2021, to February 28, 2022 were collected and the chemical components were analyzed. Caenorhabditis elegans (C. elegans) was employed to conduct the toxicological testing. The reproductive toxicity of PM2.5 to C. elegans in different seasons was evaluated by multiple reproductive endpoints. Exposure to high concentrations of PM2.5 significantly decreased the brood size and the number of fertilized eggs in utero. PM2.5 exposure also increased the number of germ cell corpses and caused abnormal expression of apoptosis-related genes (ced-9, ced-4, and ced-3), which confirmed that PM2.5 induced germline apoptosis. In addition, PM2.5 exposure significantly increased the production of reactive oxygen species (ROS) in C. elegans and the fluorescence intensity of HUS-1 protein in of transgenic strain WS1433. Meanwhile, the expression of genes related to DNA damage (cep-1, clk-2, egl-1, and hus-1) and oxidative stress (mev-1, isp-1, and gas-1) also significantly altered in C. elegans, suggesting induction of DNA damage and oxidative stress. According to Pearson correlation analyses, DNA damage and oxidative stress were significantly correlated with multiple reproductive endpoints in C. elegans. Thus, it was speculated that PM2.5 caused reproductive dysfunction and germ cell apoptosis in C. elegans may be by inducing ROS and DNA damage. In addition, heavy metals in PM2.5 were significantly correlated with multiple endpoints at physiological and biochemical, suggesting that the heavy metals might be an important contributor to the reproductive toxicity induced by PM2.5.
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Affiliation(s)
- Xiaoming Liu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Pengxiang Ge
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Zhenyu Lu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Rongying Yang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Zhengjiang Liu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Fen Zhao
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Mindong Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China.
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8
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Dhakal P, Chaudhry SI, Signorelli R, Collins KM. Serotonin signals through postsynaptic Gαq, Trio RhoGEF, and diacylglycerol to promote Caenorhabditis elegans egg-laying circuit activity and behavior. Genetics 2022; 221:iyac084. [PMID: 35579369 PMCID: PMC9252285 DOI: 10.1093/genetics/iyac084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/26/2022] [Indexed: 11/12/2022] Open
Abstract
Activated Gαq signals through phospholipase-Cβ and Trio, a Rho GTPase exchange factor (RhoGEF), but how these distinct effector pathways promote cellular responses to neurotransmitters like serotonin remains poorly understood. We used the egg-laying behavior circuit of Caenorhabditis elegans to determine whether phospholipase-Cβ and Trio mediate serotonin and Gαq signaling through independent or related biochemical pathways. Our genetic rescue experiments suggest that phospholipase-Cβ functions in neurons while Trio Rho GTPase exchange factor functions in both neurons and the postsynaptic vulval muscles. While Gαq, phospholipase-Cβ, and Trio Rho GTPase exchange factor mutants fail to lay eggs in response to serotonin, optogenetic stimulation of the serotonin-releasing HSN neurons restores egg laying only in phospholipase-Cβ mutants. Phospholipase-Cβ mutants showed vulval muscle Ca2+ transients while strong Gαq and Trio Rho GTPase exchange factor mutants had little or no vulval muscle Ca2+ activity. Treatment with phorbol 12-myristate 13-acetate that mimics 1,2-diacylglycerol, a product of PIP2 hydrolysis, rescued egg-laying circuit activity and behavior defects of Gαq signaling mutants, suggesting both phospholipase-C and Rho signaling promote synaptic transmission and egg laying via modulation of 1,2-diacylglycerol levels. 1,2-Diacylglycerol activates effectors including UNC-13; however, we find that phorbol esters, but not serotonin, stimulate egg laying in unc-13 and phospholipase-Cβ mutants. These results support a model where serotonin signaling through Gαq, phospholipase-Cβ, and UNC-13 promotes neurotransmitter release, and that serotonin also signals through Gαq, Trio Rho GTPase exchange factor, and an unidentified, phorbol 12-myristate 13-acetate-responsive effector to promote postsynaptic muscle excitability. Thus, the same neuromodulator serotonin can signal in distinct cells and effector pathways to coordinate activation of a motor behavior circuit.
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Affiliation(s)
- Pravat Dhakal
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
| | - Sana I Chaudhry
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
| | | | - Kevin M Collins
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
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Gao X, Zhang M, Lyu M, Lin S, Luo X, You W, Ke C. Role of Bmal1 in mediating the cholinergic system to regulate the behavioral rhythm of nocturnal marine molluscs. Comput Struct Biotechnol J 2022; 20:2815-2830. [PMID: 35765646 PMCID: PMC9189711 DOI: 10.1016/j.csbj.2022.05.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/18/2022] Open
Abstract
The circadian differential expression of AchE was identified using TMT quantitative proteomics; It was found that the Ach concentration and the expression levels of AchE and Bmal1 exhibit circadian cosine rhythm; The full-length sequences of AchE and nAchR were obtained by cloning technique and made available for phylogenetic analysis; The movement distance and duration of abalone increased after the injection of neostigmine methylsulfate as the AchE inhibitor; Bmal1 as the core circadian clock gene was proven to bind to AchE and nAchR, thereby regulating the movement behavior of abalone.
The circadian rhythm is one of the most general and important rhythms in biological organisms. In this study, continuous 24-h video recordings showed that the cumulative movement distance and duration of the abalone, Haliotis discus hannai, reached their maximum values between 20:00–00:00, but both were significantly lower between 08:00–12:00 than at any other time of day or night (P < 0.05). To investigate the causes of these diel differences in abalone movement behavior, their cerebral ganglia were harvested at 00:00 (group D) and 12:00 (group L) to screen for differentially expressed proteins using tandem mass tagging (TMT) quantitative proteomics. Seventy-five significantly different proteins were identified in group D vs. group L. The differences in acetylcholinesterase (AchE) expression levels between day- and nighttime and the key role in the cholinergic nervous system received particular attention during the investigation. A cosine rhythm analysis found that the concentration of acetylcholine (Ach) and the expression levels of AchE tended to be low during the day and high at night, and high during the day and low at night, respectively. However, the rhythmicity of the diel expression levels of acetylcholine receptor (nAchR) appeared to be insignificant (P > 0.05). Following the injection of three different concentrations of neostigmine methylsulfate, as an AchE inhibitor, the concentration of Ach in the hemolymph, and the expression levels of nAchR in the cerebral ganglia increased significantly (P < 0.05). Four hours after drug injection, the cumulative movement distance and duration of abalones were significantly higher than those in the uninjected control group, and the group injected with saline (P < 0.05). The expression levels of the core diurnal clock Bmal1 over a 24-h period also tended to be high during the day and low at night. First, a co-immunoprecipitation assay demonstrated the binding between Bmal1 and AchE or nAchR. A dual-luciferase gene test and electrophoretic mobility shift assay showed that Bmal1 bound to the promoter regions of AchE and nAchR. Twenty-four hours after silencing the Bmal1 gene, the expression levels of AchE and nAchR decreased significantly compared to those of the dsEGFP and PBS control groups, further showing that Bmal1 mediates the cholinergic system to regulate the behavioral rhythm of abalone. These findings shed light on the endocrine mechanism regulating the rhythmic behavior of abalone, and provide a reference for understanding the life history adaptation strategies of nocturnal organisms and the proliferation and protection of bottom dwelling economically important organisms.
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Affiliation(s)
- Xiaolong Gao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Mo Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Mingxin Lyu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Shihui Lin
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Xuan Luo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Weiwei You
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
| | - Caihuan Ke
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Fujian Key Laboratory of Genetics and Breeding of Marine Organisms, Xiamen University, Xiamen, China
- Corresponding author.
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10
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Kalia V, Niedzwiecki MM, Bradner JM, Lau FK, Anderson FL, Bucher ML, Manz KE, Schlotter AP, Fuentes ZC, Pennell KD, Picard M, Walker DI, Hu WT, Jones DP, Miller GW. Cross-species metabolomic analysis of tau- and DDT-related toxicity. PNAS NEXUS 2022; 1:pgac050. [PMID: 35707205 PMCID: PMC9186048 DOI: 10.1093/pnasnexus/pgac050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 04/28/2022] [Indexed: 01/29/2023]
Abstract
Exposure to the pesticide dichlorodiphenyltrichloroethane (DDT) has been associated with increased risk of Alzheimer's disease (AD), a disease also associated with hyperphosphorylated tau (p-tau) protein aggregation. We investigated whether exposure to DDT can exacerbate tau protein toxicity in Caenorhabditiselegans using a transgenic strain that expresses human tau protein prone to aggregation by measuring changes in size, swim behavior, respiration, lifespan, learning, and metabolism. In addition, we examined the association between cerebrospinal fluid (CSF) p-tau protein-as a marker of postmortem tau burden-and global metabolism in both a human population study and in C. elegans, using the same p-tau transgenic strain. From the human population study, plasma and CSF-derived metabolic features associated with p-tau levels were related to drug, amino acid, fatty acid, and mitochondrial metabolism pathways. A total of five metabolites overlapped between plasma and C. elegans, and four between CSF and C. elegans. DDT exacerbated the inhibitory effect of p-tau protein on growth and basal respiration. In the presence of p-tau protein, DDT induced more curling and was associated with reduced levels of amino acids but increased levels of uric acid and adenosylselenohomocysteine. Our findings in C. elegans indicate that DDT exposure and p-tau aggregation both inhibit mitochondrial function and DDT exposure can exacerbate the mitochondrial inhibitory effects of p-tau aggregation. Further, biological pathways associated with exposure to DDT and p-tau protein appear to be conserved between species.
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Affiliation(s)
- Vrinda Kalia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Megan M Niedzwiecki
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029 USA
| | - Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Fion K Lau
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Faith L Anderson
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Katherine E Manz
- School of Engineering, Brown University, Providence, RI, 02912 USA
| | - Alexa Puri Schlotter
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
| | - Zoe Coates Fuentes
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029 USA
| | - Kurt D Pennell
- School of Engineering, Brown University, Providence, RI, 02912 USA
| | - Martin Picard
- Department of Neurology, Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, 10032 USA
| | - Douglas I Walker
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029 USA
| | - William T Hu
- Department of Neurology, Rutgers Biomedical and Health Sciences, New Brunswick, NJ, 08901 USA
| | - Dean P Jones
- Division of Pulmonary, Allergy and Critical Medicine, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, 30322 USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, 10032 USA
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11
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Saberski E, Bock AK, Goodridge R, Agarwal V, Lorimer T, Rifkin SA, Sugihara G. Networks of Causal Linkage Between Eigenmodes Characterize Behavioral Dynamics of Caenorhabditis elegans. PLoS Comput Biol 2021; 17:e1009329. [PMID: 34506477 PMCID: PMC8494368 DOI: 10.1371/journal.pcbi.1009329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/06/2021] [Accepted: 08/07/2021] [Indexed: 11/18/2022] Open
Abstract
Behavioral phenotyping of model organisms has played an important role in unravelling the complexities of animal behavior. Techniques for classifying behavior often rely on easily identified changes in posture and motion. However, such approaches are likely to miss complex behaviors that cannot be readily distinguished by eye (e.g., behaviors produced by high dimensional dynamics). To explore this issue, we focus on the model organism Caenorhabditis elegans, where behaviors have been extensively recorded and classified. Using a dynamical systems lens, we identify high dimensional, nonlinear causal relationships between four basic shapes that describe worm motion (eigenmodes, also called "eigenworms"). We find relationships between all pairs of eigenmodes, but the timescales of the interactions vary between pairs and across individuals. Using these varying timescales, we create "interaction profiles" to represent an individual's behavioral dynamics. As desired, these profiles are able to distinguish well-known behavioral states: i.e., the profiles for foraging individuals are distinct from those of individuals exhibiting an escape response. More importantly, we find that interaction profiles can distinguish high dimensional behaviors among divergent mutant strains that were previously classified as phenotypically similar. Specifically, we find it is able to detect phenotypic behavioral differences not previously identified in strains related to dysfunction of hermaphrodite-specific neurons.
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Affiliation(s)
- Erik Saberski
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Antonia K. Bock
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Rachel Goodridge
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Vitul Agarwal
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Tom Lorimer
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
| | - Scott A. Rifkin
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - George Sugihara
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America
- * E-mail:
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12
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Emerson S, Hay M, Smith M, Granger R, Blauch D, Snyder N, El Bejjani R. Acetylcholine signaling genes are required for cocaine-stimulated egg laying in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2021; 11:jkab143. [PMID: 33914087 PMCID: PMC8763240 DOI: 10.1093/g3journal/jkab143] [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] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 04/20/2021] [Indexed: 11/23/2022]
Abstract
The toxicity and addictive liability associated with cocaine abuse are well-known. However, its mode of action is not completely understood, and effective pharmacotherapeutic interventions remain elusive. The cholinergic effects of cocaine on acetylcholine receptors, synthetic enzymes, and degradative enzymes have been the focus of relatively little empirical investigation. Due to its genetic tractability and anatomical simplicity, the egg laying circuit of the hermaphroditic nematode, Caenorhabditis elegans, is a powerful model system to precisely examine the genetic and molecular targets of cocaine in vivo. Here, we report a novel cocaine-induced behavioral phenotype in C. elegans, cocaine-stimulated egg laying. In addition, we present the results of an in vivo candidate suppression screen of synthetic enzymes, receptors, degradative enzymes, and downstream components of the intracellular signaling cascades of the main neurotransmitter systems that control C. elegans egg laying. Our results show that cocaine-stimulated egg laying is dependent on acetylcholine synthesis and synaptic release, functional nicotinic acetylcholine receptors, and the C. elegans acetylcholinesterases.
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Affiliation(s)
- Soren Emerson
- Neuroscience Interdisciplinary Program, Davidson College, Davidson, NC 28035, USA
| | - Megan Hay
- Biology Department, Davidson College, Davidson, NC 28035, USA
| | - Mark Smith
- Neuroscience Interdisciplinary Program, Davidson College, Davidson, NC 28035, USA
- Psychology Department, Davidson College, Davidson, NC 28035, USA
| | - Ricky Granger
- Biology Department, Davidson College, Davidson, NC 28035, USA
| | - David Blauch
- Chemistry Department, Davidson College, Davidson, NC 28035 USA
| | - Nicole Snyder
- Chemistry Department, Davidson College, Davidson, NC 28035 USA
| | - Rachid El Bejjani
- Neuroscience Interdisciplinary Program, Davidson College, Davidson, NC 28035, USA
- Biology Department, Davidson College, Davidson, NC 28035, USA
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13
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Turek M, Banasiak K, Piechota M, Shanmugam N, Macias M, Śliwińska MA, Niklewicz M, Kowalski K, Nowak N, Chacinska A, Pokrzywa W. Muscle-derived exophers promote reproductive fitness. EMBO Rep 2021; 22:e52071. [PMID: 34288362 PMCID: PMC8339713 DOI: 10.15252/embr.202052071] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 05/08/2021] [Accepted: 05/21/2021] [Indexed: 01/18/2023] Open
Abstract
Organismal functionality and reproduction depend on metabolic rewiring and balanced energy resources. However, the crosstalk between organismal homeostasis and fecundity and the associated paracrine signaling mechanisms are still poorly understood. Using Caenorhabditis elegans, we discovered that large extracellular vesicles (known as exophers) previously found to remove damaged subcellular elements in neurons and cardiomyocytes are released by body wall muscles (BWM) to support embryonic growth. Exopher formation (exopheresis) by BWM is sex-specific and a non-cell autonomous process regulated by developing embryos in the uterus. Embryo-derived factors induce the production of exophers that transport yolk proteins produced in the BWM and ultimately deliver them to newly formed oocytes. Consequently, offspring of mothers with a high number of muscle-derived exophers grew faster. We propose that the primary role of muscular exopheresis is to stimulate reproductive capacity, thereby influencing the adaptation of worm populations to the current environmental conditions.
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Affiliation(s)
- Michał Turek
- ReMedy International Research Agenda Unit, University of Warsaw, Warsaw, Poland.,Laboratory of Mitochondrial Biogenesis, Centre of New Technologies, University of Warsaw, Warsaw, Poland.,Laboratory of Animal Molecular Physiology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Banasiak
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Małgorzata Piechota
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Nilesh Shanmugam
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Matylda Macias
- Core Facility, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Małgorzata Alicja Śliwińska
- Laboratory of Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
| | - Marta Niklewicz
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Konrad Kowalski
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Natalia Nowak
- Laboratory of Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Chacinska
- ReMedy International Research Agenda Unit, University of Warsaw, Warsaw, Poland.,Laboratory of Mitochondrial Biogenesis, Centre of New Technologies, University of Warsaw, Warsaw, Poland.,IMol Polish Academy of Sciences, Warsaw, Poland
| | - Wojciech Pokrzywa
- Laboratory of Protein Metabolism, International Institute of Molecular and Cell Biology, Warsaw, Poland
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14
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Li J, Qu M, Wang M, Yue Y, Chen Z, Liu R, Bu Y, Li Y. Reproductive toxicity and underlying mechanisms of di(2-ethylhexyl) phthalate in nematode Caenorhabditis elegans. J Environ Sci (China) 2021; 105:1-10. [PMID: 34130826 DOI: 10.1016/j.jes.2020.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
DEHP (di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using DEHP concentrations of 10, 1, and 0.1 mg/L, we showed that DEHP reduced the reproductive capacity of Caenorhabditis elegans after 72 hr. of exposure. DEHP exposure reduced the reproductive capacity in terms of decreased brood sizes, egg hatchability (0.1, 1 and 10 mg/L), and egg-laying rate (1 and 10 mg/L), and increased numbers of fertilized eggs in the uterus (1 and 10 mg/L). DEHP also caused damage to gonad development. DEHP decreased the total number of germline cells, and decreased the relative area of the gonad arm of all exposure groups, with worms in the 1 mg/L DEHP exposure group having the minimum gonad arm area. Additionally, DEHP caused a significant concentration-dependent increase in the expression of unc-86. Autophagy and ROS contributed to the enhancement of DEHP toxicity in reducing reproductive capacity, and glutathione peroxidase and superoxide dismutase were activated as the antioxidant defense in this study. Hence, we found that DEHP has a dual effect on nematodes. Higher concentration (10 mg/L) DEHP can inhibit the expression of autophagy genes (atg-18, atg-7, bec-1, lgg-1 and unc-51), and lower concentrations (0.1 and 1 mg/L) can promote the expression of autophagy genes. Our data highlight the potential environmental risk of DEHP in inducing reproductive toxicity toward the gonad development and reproductive capacity of environmental organisms.
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Affiliation(s)
- Jingjing Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Man Qu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Mei Wang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Ying Yue
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Zhaofang Chen
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Ran Liu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China
| | - Yuanqing Bu
- Nanjing Institute of Environmental Science, Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Ecology and Environment, Nanjing 210042, China
| | - Yunhui Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
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15
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Sun Q, Liu C, Jiang K, Fang Y, Kong C, Fu J, Liu Y. A preliminary study on the neurotoxic mechanism of harmine in Caenorhabditis elegans. Comp Biochem Physiol C Toxicol Pharmacol 2021; 245:109038. [PMID: 33794375 DOI: 10.1016/j.cbpc.2021.109038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/15/2021] [Accepted: 03/20/2021] [Indexed: 12/31/2022]
Abstract
Harmine is a beta-carboline and harmala alkaloid with extensive bioactivities. However, its toxicity, especially in neural system, is not systematically assessed and the toxic mechanism is not yet clear. Using Caenorhabditis elegans (C. elegans) as a model system, we found that harmine exhibited dosage dependent (0, 5, 10, 20, 40, 80, 160, and 320 μmol/L) toxic effect, such as growth inhibition, egg laying defects, shortened life span and increased mortality. Although harmine did not result in obvious structural alterations in neurite or death of neurons, it did show direct acetylcholinesterase inhibition activity. Further, we found that harmine treatment decreased worm pharyngeal pump rate and lowered the content of nitric oxide (NO) in worm body, implying foraging disorders, which is an indicator of acetylcholinergic neuron activity inhibition. Besides, network pharmacology and molecular docking reveals that acetylcholinesterase is one of the major neural toxicity targets as well. Above all, harmine can directly inhibit the activity of acetylcholinesterase, leading to excessive accumulation of acetylcholine, which may be one of the harmine neurotoxicity mechanisms.
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Affiliation(s)
- Qianqian Sun
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Cen Liu
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Kunxiu Jiang
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Yongsheng Fang
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Chuchu Kong
- Beijing University of Chinese Medicine, Beijing 102488, China
| | - Jin Fu
- College of Xinjiang Uyghur Medicine, Xinjiang 848000, China
| | - Yonggang Liu
- Beijing University of Chinese Medicine, Beijing 102488, China.
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16
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Ravi B, Zhao J, Chaudhry I, Signorelli R, Bartole M, Kopchock RJ, Guijarro C, Kaplan JM, Kang L, Collins KM. Presynaptic Gαo (GOA-1) signals to depress command neuron excitability and allow stretch-dependent modulation of egg laying in Caenorhabditis elegans. Genetics 2021; 218:6284136. [PMID: 34037773 DOI: 10.1093/genetics/iyab080] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/18/2021] [Indexed: 12/29/2022] Open
Abstract
Egg laying in the nematode worm Caenorhabditis elegans is a two-state behavior modulated by internal and external sensory input. We have previously shown that homeostatic feedback of embryo accumulation in the uterus regulates bursting activity of the serotonergic HSN command neurons that sustains the egg-laying active state. How sensory feedback of egg release signals to terminate the egg-laying active state is less understood. We find that Gαo, a conserved Pertussis Toxin-sensitive G protein, signals within HSN to inhibit egg-laying circuit activity and prevent entry into the active state. Gαo signaling hyperpolarizes HSN, reducing HSN Ca2+ activity and input onto the postsynaptic vulval muscles. Loss of inhibitory Gαo signaling uncouples presynaptic HSN activity from a postsynaptic, stretch-dependent homeostat, causing precocious entry into the egg-laying active state when only a few eggs are present in the uterus. Feedback of vulval opening and egg release activates the uv1 neuroendocrine cells which release NLP-7 neuropeptides which signal to inhibit egg laying through Gαo-independent mechanisms in the HSNs and Gαo-dependent mechanisms in cells other than the HSNs. Thus, neuropeptide and inhibitory Gαo signaling maintains a bi-stable state of electrical excitability that dynamically controls circuit activity in response to both external and internal sensory input to drive a two-state behavior output.
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Affiliation(s)
- Bhavya Ravi
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL USA 33136.,Department of Biology, University of Miami, Coral Gables, FL USA 33146
| | - Jian Zhao
- Department of Neuroscience, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA 02114
| | - I Chaudhry
- Department of Biology, University of Miami, Coral Gables, FL USA 33146
| | | | - Mattingly Bartole
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL USA 33136.,Department of Biology, University of Miami, Coral Gables, FL USA 33146
| | | | | | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA 02114
| | - Lijun Kang
- Department of Neuroscience, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Kevin M Collins
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL USA 33136.,Department of Biology, University of Miami, Coral Gables, FL USA 33146
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17
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Maertens T, Schöll E, Ruiz J, Hövel P. Multilayer network analysis of C. elegans: Looking into the locomotory circuitry. Neurocomputing 2021. [DOI: 10.1016/j.neucom.2020.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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18
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Signal Decoding for Glutamate Modulating Egg Laying Oppositely in Caenorhabditis elegans under Varied Environmental Conditions. iScience 2020; 23:101588. [PMID: 33089099 PMCID: PMC7567941 DOI: 10.1016/j.isci.2020.101588] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/07/2020] [Accepted: 09/16/2020] [Indexed: 11/24/2022] Open
Abstract
Animals' ability to sense environmental cues and to integrate this information to control fecundity is vital for continuing the species lineage. In this study, we observed that the sensory neurons Amphid neuron (ASHs and ADLs) differentially regulate egg-laying behavior in Caenorhabditis elegans under varied environmental conditions via distinct neuronal circuits. Under standard culture conditions, ASHs tonically release a small amount of glutamate and inhibit Hermaphrodite specific motor neuron (HSN) activities and egg laying via a highly sensitive Glutamate receptor (GLR)-5 receptor. In contrast, under Cu2+ stimulation, ASHs and ADLs may release a large amount of glutamate and inhibit Amphid interneuron (AIA) interneurons via low-sensitivity Glutamate-gated chloride channel (GLC)-3 receptor, thus removing the inhibitory roles of AIAs on HSN activity and egg laying. However, directly measuring the amount of glutamate released by sensory neurons under different conditions and assaying the binding kinetics of receptors with the neurotransmitter are still required to support this study directly. Short-term exposure of CuSO4 evokes hyperactive egg laying ASHs inhibit HSNs and egg laying via GLR-5 receptor under no Cu2+ treatment AIA interneurons suppress HSNs and thus egg laying through ACR-14 signaling Under noxious Cu2+ treatment, ASHs and ADLs suppress AIAs and augment egg laying
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19
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Téllez-Arreola JL, Silva M, Martínez-Torres A. MCTP-1 modulates neurotransmitter release in C. elegans. Mol Cell Neurosci 2020; 107:103528. [PMID: 32650044 DOI: 10.1016/j.mcn.2020.103528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 11/30/2022] Open
Abstract
Multiple C2 and Transmembrane Domain Proteins (MCTPs) are putative calcium sensors. Proteins that contain C2 domains play essential roles in membrane trafficking and exocytosis; however, MCTPs functions in neurotransmitter release are not known. Here we report that in C. elegans mctp-1 is under the control of two promoters - one active in the nervous system and the second in the spermatheca. We generated and characterized a loss of function amt1 mutant and compared it to a previously published loss of function mutant (av112). Loss of mctp-1 function causes defects in egg-laying, crawling velocity, and thrashing rates. Both amt1 and av112 mutants are hyposensitive to the acetylcholinesterase blocker aldicarb, suggesting that MCTP-1 may play a role in synaptic vesicle release.
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Affiliation(s)
- José Luis Téllez-Arreola
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76215 Juriquilla, Querétaro, México; School of Biological Sciences, University of Utah, Salt Lake City, United States
| | - Malan Silva
- School of Biological Sciences, University of Utah, Salt Lake City, United States
| | - Ataúlfo Martínez-Torres
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76215 Juriquilla, Querétaro, México.
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20
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Pathak A, Chatterjee N, Sinha S. Developmental trajectory of Caenorhabditis elegans nervous system governs its structural organization. PLoS Comput Biol 2020; 16:e1007602. [PMID: 31895942 PMCID: PMC6959611 DOI: 10.1371/journal.pcbi.1007602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 01/14/2020] [Accepted: 12/11/2019] [Indexed: 11/22/2022] Open
Abstract
A central problem of neuroscience involves uncovering the principles governing the organization of nervous systems which ensure robustness in brain development. The nematode Caenorhabditis elegans provides us with a model organism for studying this question. In this paper, we focus on the invariant connection structure and spatial arrangement of the neurons comprising the somatic neuronal network of this organism to understand the key developmental constraints underlying its design. We observe that neurons with certain shared characteristics-such as, neural process lengths, birth time cohort, lineage and bilateral symmetry-exhibit a preference for connecting to each other. Recognizing the existence of such homophily and their relative degree of importance in determining connection probability within neurons (for example, in synapses, symmetric pairing is the most dominant factor followed by birth time cohort, process length and lineage) helps in connecting specific neuronal attributes to the topological organization of the network. Further, the functional identities of neurons appear to dictate the temporal hierarchy of their appearance during the course of development. Providing crucial insights into principles that may be common across many organisms, our study shows how the trajectory in the developmental landscape constrains the structural organization of a nervous system.
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Affiliation(s)
- Anand Pathak
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India
| | | | - Sitabhra Sinha
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, India
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21
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Da Silva JD, Oliveira S, Pereira-Sousa J, Teixeira-Castro A, Costa MD, Maciel P. Loss of egli-1, the Caenorhabditis elegans Orthologue of a Downstream Target of SMN, Leads to Abnormalities in Sensorimotor Integration. Mol Neurobiol 2019; 57:1553-1569. [PMID: 31797327 DOI: 10.1007/s12035-019-01833-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 11/12/2019] [Indexed: 11/28/2022]
Abstract
The connectome of Caenorhabditis elegans has been extensively studied and fully mapped, allowing researchers to more confidently conclude on the impact of any change in neuronal circuits based on behavioral data. One of the more complex sensorimotor circuits in nematodes is the one that regulates the integration of feeding status with the subsequent behavioral responses that allow animals to adapt to environmental conditions. Here, we have characterized a Caenorhabditis elegans knockout model of the egli-1 gene (previously known as tag-175). This is an orthologue of the stasimon/tmem41b gene, a downstream target of SMN, the depleted protein in spinal muscular atrophy (SMA), which partially recapitulates the SMA phenotype in fly and zebrafish models when mutated. Surprisingly, egli-1 mutants reveal no deficits in motor function. Instead, they show functional impairment of a specific neuronal circuit, leading to defects in the integration of sensorial information related to food abundance, with consequences at the level of locomotion adaptation, egg laying, and the response to aversive chemical stimuli. This work has demonstrated for the first time the relevance of egli-1 in the nervous system, as well as revealed a function for this gene, which had remained elusive so far.
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Affiliation(s)
- Jorge Diogo Da Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Stéphanie Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana Pereira-Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Marta Daniela Costa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal. .,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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22
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Baraldo G, Etemad S, Weiss AKH, Jansen-Dürr P, Mack HID. Modulation of serotonin signaling by the putative oxaloacetate decarboxylase FAHD-1 in Caenorhabditis elegans. PLoS One 2019; 14:e0220434. [PMID: 31412049 PMCID: PMC6693844 DOI: 10.1371/journal.pone.0220434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 07/16/2019] [Indexed: 11/19/2022] Open
Abstract
Human fumarylacetoacetate hydrolase (FAH) domain containing protein 1 (FAHD1) is a mitochondrial oxalocatate decarboxylase, the first of its kind identified in eukaryotes. The physiological role of FAHD1 in other eukaryotes is still poorly understood. In C. elegans loss of the FAHD1 ortholog FAHD-1 was reported to impair mitochondrial function, locomotion and egg-laying behavior, yet the underlying mechanisms remained unclear. Using tissue-specific rescue of fahd-1(-) worms, we find that these phenotypic abnormalities are at least in part due to fahd-1’s function in neurons. Moreover, we show that egg-laying defects in fahd-1(-) worms can be fully rescued by external dopamine administration and that depletion of fahd-1 expression induces expression of several enzymes involved in serotonin biosynthesis. Together, our results support a role for fahd-1 in modulating serotonin levels and suggest this protein as a novel link between metabolism and neurotransmitter signaling in the nervous system. Finally, we propose a model to explain how a metabolic defect could ultimately lead to marked changes in neuronal signaling.
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Affiliation(s)
- Giorgia Baraldo
- Department of Molecular and Cell Biology, Research Institute for Biomedical Ageing Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Solmaz Etemad
- Department of Molecular and Cell Biology, Research Institute for Biomedical Ageing Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Alexander K. H. Weiss
- Department of Molecular and Cell Biology, Research Institute for Biomedical Ageing Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Pidder Jansen-Dürr
- Department of Molecular and Cell Biology, Research Institute for Biomedical Ageing Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
- * E-mail: (PJD); (HIDM)
| | - Hildegard I. D. Mack
- Department of Biochemistry and Genetics of Aging, Research Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- * E-mail: (PJD); (HIDM)
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23
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Luo S, Jiang X, Jia L, Tan C, Li M, Yang Q, Du Y, Ding C. In Vivo and In Vitro Antioxidant Activities of Methanol Extracts from Olive Leaves on Caenorhabditis elegans. Molecules 2019; 24:E704. [PMID: 30781358 PMCID: PMC6412793 DOI: 10.3390/molecules24040704] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 01/27/2023] Open
Abstract
The aim of this study was to evaluate the antioxidant activities of extracts from olive leaves (EOL). The main contents of EOL were determined by colorimetric methods. The antioxidant activities were assessed by measuring the scavenging free radicals in vitro. To investigate the antioxidant activity in vivo, we detected the survival of Caenorhabditis elegans, under thermal stress. Subsequently the reactive oxygen species (ROS) level, activities of antioxidant enzymes, the expression of HSP-16.2 and the translocation of daf-16 were measured. The results showed that, polyphenols was the main component. EOL could well scavenge DPPH and superoxide anion radicals in vitro. Compared to the control group, the survival rate of C. elegans treated with EOL was extended by 10.43%, under heat stress. The ROS level was reduced, while the expression of hsp-16.2 was increased to protect the organism against the increasing ROS. The level of malondialdehyde (MDA) also decreased sharply. The activities of inner antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were potentiated, which might have had a correlation with the DAF-16 transcription factor that was induced-turned into the nuclear. Therefore, EOL showed a strong antioxidant ability in vitro and in vivo. Hence, it could be a potential candidate when it came to medicinal and edible plants.
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Affiliation(s)
- Siyuan Luo
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Xuelian Jiang
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Liping Jia
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Chengyue Tan
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Min Li
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Qiuyu Yang
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Yanlin Du
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
| | - Chunbang Ding
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
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Brewer JC, Olson AC, Collins KM, Koelle MR. Serotonin and neuropeptides are both released by the HSN command neuron to initiate Caenorhabditis elegans egg laying. PLoS Genet 2019; 15:e1007896. [PMID: 30677018 PMCID: PMC6363226 DOI: 10.1371/journal.pgen.1007896] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/05/2019] [Accepted: 12/13/2018] [Indexed: 01/03/2023] Open
Abstract
Neurons typically release both a small-molecule neurotransmitter and one or more neuropeptides, but how these two types of signal from the same neuron might act together remains largely obscure. For example, serotonergic neurons in mammalian brain express the neuropeptide Substance P, but it is unclear how this co-released neuropeptide might modulate serotonin signaling. We studied this issue in C. elegans, in which all serotonergic neurons express the neuropeptide NLP-3. The serotonergic Hermaphrodite Specific Neurons (HSNs) are command motor neurons within the egg-laying circuit which have been shown to release serotonin to initiate egg-laying behavior. We found that egg-laying defects in animals lacking serotonin were far milder than in animals lacking HSNs, suggesting that HSNs must release other signal(s) in addition to serotonin to stimulate egg laying. While null mutants for nlp-3 had only mild egg-laying defects, animals lacking both serotonin and NLP-3 had severe defects, similar to those of animals lacking HSNs. Optogenetic activation of HSNs induced egg laying in wild-type animals, and in mutant animals lacking either serotonin or NLP-3, but failed to induce egg laying in animals lacking both. We recorded calcium activity in the egg-laying muscles of animals lacking either serotonin, NLP-3, or both. The single mutants, and to a greater extent the double mutant, showed muscle activity that was uncoordinated and unable to expel eggs. Specifically, the vm2 muscles cells, which are direct postsynaptic targets of the HSN, failed to contract simultaneously with other egg-laying muscle cells. Our results show that the HSN neurons use serotonin and the neuropeptide NLP-3 as partially redundant co-transmitters that together stimulate and coordinate activity of the target cells onto which they are released. Activity of the brain results from neurons communicating with each other using chemical signals. A typical neuron releases two kinds of chemical signals: a small molecule neurotransmitter, such as serotonin, and one or more small proteins, called neuropeptides. For example, neurons in the human brain that release serotonin, a neurotransmitter thought to be involved in depression, also release the neuropeptide Substance P. Neuroscientists have typically studied the effects of neurotransmitters and neuropeptides separately, without considering how these two types of signals from the same neuron might be integrated. Here we analyzed how specific neurons in the model organism C. elegans use both serotonin and a neuropeptide together. The Hermaphrodite Specific Neurons (HSNs) activate a small group of neurons and muscles to generate egg-laying behavior. Killing the HSNs resulted in animals unable to lay eggs, but we found that eliminating either serotonin or the neuropeptide resulted in HSNs that still remained able to activate egg laying. However, eliminating both serotonin and the neuropeptide resulted in HSNs unable to activate coordinated contractions of the egg-laying muscles. Our results show that in a living animal, serotonin acts in concert with a co-released neuropeptide to carry out its functions.
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Affiliation(s)
- Jacob C. Brewer
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Andrew C. Olson
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Kevin M. Collins
- Department of Biology, University of Miami, Coral Gables, Florida, United States of America
| | - Michael R. Koelle
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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25
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Refai O, Blakely RD. Blockade and reversal of swimming-induced paralysis in C. elegans by the antipsychotic and D2-type dopamine receptor antagonist azaperone. Neurochem Int 2018; 123:59-68. [PMID: 29800604 DOI: 10.1016/j.neuint.2018.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 05/21/2018] [Accepted: 05/21/2018] [Indexed: 10/16/2022]
Abstract
The catecholamine neurotransmitter dopamine (DA) exerts powerful modulatory control of physiology and behavior across phylogeny. Perturbations of DA signaling in humans are associated with multiple neurodegenerative and behavioral disorders, including Parkinson's disease, attention-deficit/hyperactivity disorder, addiction and schizophrenia. In the nematode C. elegans, DA signaling regulates mating behavior, learning, food seeking and locomotion. Previously, we demonstrated that loss of function mutations in the dat-1 gene that encodes the presynaptic DA transporter (DAT-1) results in a rapid cessation of movement when animals are placed in water, termed Swimming Induced Paralysis (Swip). Loss of function mutations in genes that support DA biosynthesis, DA vesicular packaging and DA action at the extrasynaptic D2-type DA receptor DOP-3 suppress Swip in dat-1 animals, consistent with paralysis as arising from excessive DA signaling. Although animals grown on the vesicular monoamine transporter antagonist reserpine diminish Swip, the drug must be applied chronically, can impact the signaling of multiple biogenic amines, and has been reported to have penetrant, off-target actions. Here, we demonstrate that the antipsychotic drug azaperone potently and rapidly suppresses Swip behavior in either dat-1 mutants, as well as in wildtype animals treated with the DAT-1 antagonist nisoxetine, with genetic experiments consistent with DOP-3 antagonism as the mechanism of Swip suppression. Reversal of Swip in previously paralyzed dat-1 animals by azaperone application demonstrates an otherwise functionally-intact swimming circuit in these mutants. Finally, whereas azaperone suppresses DA-dependent Swip, the drug fails to attenuate the DA-independent paralysis induced by βPEA, aldicarb or genetic disruption of γ-aminobutyric acid (GABA) signaling. We discuss our findings with respect to the use of azaperone as a potent and selective tool in the identification and analysis of presynaptic mechanisms that regulate DA signaling.
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Affiliation(s)
- Osama Refai
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, FL, USA
| | - Randy D Blakely
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA.
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26
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Mondal S, Hegarty E, Sahn JJ, Scott LL, Gökçe SK, Martin C, Ghorashian N, Satarasinghe PN, Iyer S, Sae-Lee W, Hodges TR, Pierce JT, Martin SF, Ben-Yakar A. High-Content Microfluidic Screening Platform Used To Identify σ2R/Tmem97 Binding Ligands that Reduce Age-Dependent Neurodegeneration in C. elegans SC_APP Model. ACS Chem Neurosci 2018; 9:1014-1026. [PMID: 29426225 DOI: 10.1021/acschemneuro.7b00428] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nematode Caenorhabditis elegans, with tractable genetics and a well-defined nervous system, provides a unique whole-animal model system to identify novel drug targets and therapies for neurodegenerative diseases. Large-scale drug or target screens in models that recapitulate the subtle age- and cell-specific aspects of neurodegenerative diseases are limited by a technological requirement for high-throughput analysis of neuronal morphology. Recently, we developed a single-copy model of amyloid precursor protein (SC_APP) induced neurodegeneration that exhibits progressive degeneration of select cholinergic neurons. Our previous work with this model suggests that small molecule ligands of the sigma 2 receptor (σ2R), which was recently cloned and identified as transmembrane protein 97 (TMEM97), are neuroprotective. To determine structure-activity relationships for unexplored chemical space in our σ2R/Tmem97 ligand collection, we developed an in vivo high-content screening (HCS) assay to identify potential drug leads. The HCS assay uses our recently developed large-scale microfluidic immobilization chip and automated imaging platform. We discovered norbenzomorphans that reduced neurodegeneration in our C. elegans model, including two compounds that demonstrated significant neuroprotective activity at multiple doses. These findings provide further evidence that σ2R/Tmem97-binding norbenzomorphans may represent a new drug class for treating neurodegenerative diseases.
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27
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Fu J, Zhang H, Huang W, Zhu X, Sheng Y, Song E, Xu T. AIM interneurons mediate feeding suppression through the TYRA-2 receptor in C. elegans. BIOPHYSICS REPORTS 2018; 4:17-24. [PMID: 29577066 PMCID: PMC5860128 DOI: 10.1007/s41048-018-0046-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/23/2017] [Indexed: 12/02/2022] Open
Abstract
Feeding behavior is the most fundamental behavior in C. elegans. Our previous results have dissected the central integration circuit for the regulation of feeding, which integrates opposing sensory inputs and regulates feeding behavior in a nonlinear manner. However, the peripheral integration that acts downstream of the central integration circuit to modulate feeding remains largely unknown. Here, we find that a Gαi/o-coupled tyramine receptor, TYRA-2, is involved in peripheral feeding suppression. TYRA-2 suppresses feeding behavior via the AIM interneurons, which receive tyramine/octopamine signals from RIM/RIC neurons in the central integration circuit. Our results reveal previously unidentified roles for the receptor TYRA-2 and the AIM interneurons in feeding regulation, providing a further understanding of how biogenic amines tyramine and octopamine regulate feeding behavior.
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Affiliation(s)
- Jiajun Fu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,2College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Haining Zhang
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Wenming Huang
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Xinyu Zhu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Yi Sheng
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Eli Song
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Tao Xu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,2College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China.,3Key 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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28
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Barr MM, García LR, Portman DS. Sexual Dimorphism and Sex Differences in Caenorhabditis elegans Neuronal Development and Behavior. Genetics 2018; 208:909-935. [PMID: 29487147 PMCID: PMC5844341 DOI: 10.1534/genetics.117.300294] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/05/2018] [Indexed: 01/05/2023] Open
Abstract
As fundamental features of nearly all animal species, sexual dimorphisms and sex differences have particular relevance for the development and function of the nervous system. The unique advantages of the nematode Caenorhabditis elegans have allowed the neurobiology of sex to be studied at unprecedented scale, linking ultrastructure, molecular genetics, cell biology, development, neural circuit function, and behavior. Sex differences in the C. elegans nervous system encompass prominent anatomical dimorphisms as well as differences in physiology and connectivity. The influence of sex on behavior is just as diverse, with biological sex programming innate sex-specific behaviors and modifying many other aspects of neural circuit function. The study of these differences has provided important insights into mechanisms of neurogenesis, cell fate specification, and differentiation; synaptogenesis and connectivity; principles of circuit function, plasticity, and behavior; social communication; and many other areas of modern neurobiology.
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Affiliation(s)
- Maureen M Barr
- Department of Genetics, Rutgers University, Piscataway, New Jersey 08854-8082
| | - L Rene García
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Douglas S Portman
- Department of Biomedical Genetics, University of Rochester, New York 14642
- Department of Neuroscience, University of Rochester, New York 14642
- Department of Biology, University of Rochester, New York 14642
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29
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Doyle SR, Bourguinat C, Nana-Djeunga HC, Kengne-Ouafo JA, Pion SDS, Bopda J, Kamgno J, Wanji S, Che H, Kuesel AC, Walker M, Basáñez MG, Boakye DA, Osei-Atweneboana MY, Boussinesq M, Prichard RK, Grant WN. Genome-wide analysis of ivermectin response by Onchocerca volvulus reveals that genetic drift and soft selective sweeps contribute to loss of drug sensitivity. PLoS Negl Trop Dis 2017; 11:e0005816. [PMID: 28746337 PMCID: PMC5546710 DOI: 10.1371/journal.pntd.0005816] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 08/07/2017] [Accepted: 07/19/2017] [Indexed: 12/30/2022] Open
Abstract
Background Treatment of onchocerciasis using mass ivermectin administration has reduced morbidity and transmission throughout Africa and Central/South America. Mass drug administration is likely to exert selection pressure on parasites, and phenotypic and genetic changes in several Onchocerca volvulus populations from Cameroon and Ghana—exposed to more than a decade of regular ivermectin treatment—have raised concern that sub-optimal responses to ivermectin's anti-fecundity effect are becoming more frequent and may spread. Methodology/Principal findings Pooled next generation sequencing (Pool-seq) was used to characterise genetic diversity within and between 108 adult female worms differing in ivermectin treatment history and response. Genome-wide analyses revealed genetic variation that significantly differentiated good responder (GR) and sub-optimal responder (SOR) parasites. These variants were not randomly distributed but clustered in ~31 quantitative trait loci (QTLs), with little overlap in putative QTL position and gene content between the two countries. Published candidate ivermectin SOR genes were largely absent in these regions; QTLs differentiating GR and SOR worms were enriched for genes in molecular pathways associated with neurotransmission, development, and stress responses. Finally, single worm genotyping demonstrated that geographic isolation and genetic change over time (in the presence of drug exposure) had a significantly greater role in shaping genetic diversity than the evolution of SOR. Conclusions/Significance This study is one of the first genome-wide association analyses in a parasitic nematode, and provides insight into the genomics of ivermectin response and population structure of O. volvulus. We argue that ivermectin response is a polygenically-determined quantitative trait (QT) whereby identical or related molecular pathways but not necessarily individual genes are likely to determine the extent of ivermectin response in different parasite populations. Furthermore, we propose that genetic drift rather than genetic selection of SOR is the underlying driver of population differentiation, which has significant implications for the emergence and potential spread of SOR within and between these parasite populations. Onchocerciasis is a human parasitic disease endemic across large areas of Sub-Saharan Africa, where more than 99% of the estimated 100 million people globally at-risk live. The microfilarial stage of Onchocerca volvulus causes pathologies ranging from mild itching to visual impairment and ultimately, irreversible blindness. Mass administration of ivermectin kills microfilariae and has an anti-fecundity effect on adult worms by temporarily inhibiting the development in utero and/or release into the skin of new microfilariae, thereby reducing morbidity and transmission. Phenotypic and genetic changes in some parasite populations that have undergone multiple ivermectin treatments in Cameroon and Ghana have raised concern that sub-optimal response to ivermectin's anti-fecundity effect may increase in frequency, reducing the impact of ivermectin-based control measures. We used next generation sequencing of small pools of parasites to define genome-wide genetic differences between phenotypically characterised good and sub-optimal responder parasites from Cameroon and Ghana, and identified multiple regions of the genome that differentiated the response types. These regions were largely different between parasites from these two countries but revealed common molecular pathways that might be involved in determining the extent of response to ivermectin's anti-fecundity effect. These data reveal a more complex than previously described pattern of genetic diversity among O. volvulus populations that differ in their geography and response to ivermectin treatment.
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Affiliation(s)
- Stephen R. Doyle
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Australia
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
- * E-mail: (SRD); (RKP); (WNG)
| | - Catherine Bourguinat
- Institute of Parasitology, McGill University, Sainte Anne-de-Bellevue, Québec, Canada
| | - Hugues C. Nana-Djeunga
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Jonas A. Kengne-Ouafo
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Sébastien D. S. Pion
- Institut de Recherche pour le Développement (IRD), IRD UMI 233 TransVIHMI – Université Montpellier – INSERM U1175, Montpellier, France
| | - Jean Bopda
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Samuel Wanji
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Hua Che
- Institute of Parasitology, McGill University, Sainte Anne-de-Bellevue, Québec, Canada
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (WHO/TDR), World Health Organization, Geneva, Switzerland
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, United Kingdom
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, United Kingdom
| | - Daniel A. Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Mike Y. Osei-Atweneboana
- Department of Environmental Biology and Health Water Research Institute, Council for Scientific and Industrial Research (CSIR), Accra, Ghana
| | - Michel Boussinesq
- Institut de Recherche pour le Développement (IRD), IRD UMI 233 TransVIHMI – Université Montpellier – INSERM U1175, Montpellier, France
| | - Roger K. Prichard
- Institute of Parasitology, McGill University, Sainte Anne-de-Bellevue, Québec, Canada
- * E-mail: (SRD); (RKP); (WNG)
| | - Warwick N. Grant
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Australia
- * E-mail: (SRD); (RKP); (WNG)
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The Annona muricata leaf ethanol extract affects mobility and reproduction in mutant strain NB327 Caenorhabditis elegans. Biochem Biophys Rep 2017; 10:282-286. [PMID: 28955756 PMCID: PMC5614673 DOI: 10.1016/j.bbrep.2017.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 04/03/2017] [Accepted: 04/23/2017] [Indexed: 12/29/2022] Open
Abstract
The C. elegans NB327 mutant strain is characterized for the knockdown of the dic-1 gene. The dic-1 gene is homologous to the dice-1 gene in humans, encoding the protein DICE-1 as a tumor suppressor. Absence or under-regulation of the dice-1 gene can be reflected in lung and prostate cancer [17], [18]. This study evaluated the effect of EEAML on the C. elegans NB327 mutant strain. Phenotypic aspects such as morphology, body length, locomotion, and reproductive behaviour were analyzed. It is important to emphasize that the strain presents a phenotype characteristic with respect to egg laying and hatching. Reported studies showed that Annona muricata extract and its active components evidence anti-cancer and anti-tumor effects, through experimentation in vivo and in vitro models. However, neurotoxicity has been reported as a side effect. The results showed that the mutant strain NB327 was exposed to EEAML (5 mg/ml) concentration, it showed a significant decrease in average locomotion, resulting in 13 undulations in 30 s. This contrasts with the control strain's 17.5 undulations in 30 s. Similarly, the number of progenies was reduced from 188 progenies (control strain) to 114 and 92 progenies at the dose of (1 mg/ml and 5 mg/m) EEAML. The results of this study suggest that EEAML has a possible neurotoxic effect in concentrations equal to or greater than 5 mg/ml. Also, it does not have positive effects on the mutant strain of Caenorhabditis elegans NB327 phenotype.
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31
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Complexity and Vulnerability Analysis of the C. Elegans Gap Junction Connectome. ENTROPY 2017. [DOI: 10.3390/e19030104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Zang KE, Ho E, Ringstad N. Inhibitory peptidergic modulation of C. elegans serotonin neurons is gated by T-type calcium channels. eLife 2017; 6. [PMID: 28165324 PMCID: PMC5330680 DOI: 10.7554/elife.22771] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/06/2017] [Indexed: 12/30/2022] Open
Abstract
Serotonin is an evolutionarily ancient molecule that functions in generating and modulating many behavioral states. Although much is known about how serotonin acts on its cellular targets, how serotonin release is regulated in vivo remains poorly understood. In the nematode C. elegans, serotonin neurons that drive female reproductive behavior are directly modulated by inhibitory neuropeptides. Here, we report the isolation of mutants in which inhibitory neuropeptides fail to properly modulate serotonin neurons and the behavior they mediate. The corresponding mutations affect the T-type calcium channel CCA-1 and symmetrically re-tune its voltage-dependencies of activation and inactivation towards more hyperpolarized potentials. This shift in voltage dependency strongly and specifically bypasses the behavioral and cell physiological effects of peptidergic inhibition on serotonin neurons. Our results indicate that T-type calcium channels are critical regulators of a C. elegans serotonergic circuit and demonstrate a mechanism in which T-type channels functionally gate inhibitory modulation in vivo.
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Affiliation(s)
- Kara E Zang
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
| | - Elver Ho
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
| | - Niels Ringstad
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
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Collins KM, Bode A, Fernandez RW, Tanis JE, Brewer JC, Creamer MS, Koelle MR. Activity of the C. elegans egg-laying behavior circuit is controlled by competing activation and feedback inhibition. eLife 2016; 5. [PMID: 27849154 PMCID: PMC5142809 DOI: 10.7554/elife.21126] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/14/2016] [Indexed: 01/13/2023] Open
Abstract
Like many behaviors, Caenorhabditis elegans egg laying alternates between inactive and active states. To understand how the underlying neural circuit turns the behavior on and off, we optically recorded circuit activity in behaving animals while manipulating circuit function using mutations, optogenetics, and drugs. In the active state, the circuit shows rhythmic activity phased with the body bends of locomotion. The serotonergic HSN command neurons initiate the active state, but accumulation of unlaid eggs also promotes the active state independent of the HSNs. The cholinergic VC motor neurons slow locomotion during egg-laying muscle contraction and egg release. The uv1 neuroendocrine cells mechanically sense passage of eggs through the vulva and release tyramine to inhibit egg laying, in part via the LGC-55 tyramine-gated Cl- channel on the HSNs. Our results identify discrete signals that entrain or detach the circuit from the locomotion central pattern generator to produce active and inactive states. DOI:http://dx.doi.org/10.7554/eLife.21126.001 It has been said that if the human brain were so simple that we could understand it, we would be so simple that we couldn’t. This quote neatly captures the challenge of working out how 80 billion neurons collectively generate our thoughts and behavior. Fortunately, the nervous system is also organized into simpler units called circuits. Each consists of a relatively small number of neurons, which communicate with one another to control as little as a single behavior. These circuits should in principle be simple enough for us to understand, particularly if we study them in nervous systems less complex than our own. Despite this, there is currently not a single circuit in any organism in which we can explain how communication between individual neurons generates behavior. Collins et al. therefore set out to characterize a simple neural circuit in one of the simplest model organisms: the egg-laying circuit of the worm C. elegans. Using mutations, drugs and molecular genetic techniques, Collins et al. systematically altered the activity and signaling of each of the neurons within the egg-laying circuit. The experiments revealed that cells called command neurons trigger egg laying by producing signals that switch on the rest of the circuit. Once activated, the circuit is able to respond to waves of activity from a second circuit – called the central pattern generator – that also controls the worm’s movement. Finally, laying an egg activates a third set of neurons, which release a signal that returns the circuit to its inactive state. The use of distinct signals and neurons to activate the circuit, to coordinate its ongoing activity, and to inactivate the circuit when its task is complete also applies to many other neural circuits. Now that these signals have been identified in one circuit, it should be possible to build on these findings to better understand how others work. DOI:http://dx.doi.org/10.7554/eLife.21126.002
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Affiliation(s)
- Kevin M Collins
- Department of Biology, University of Miami, Coral Gables, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Addys Bode
- Department of Biology, University of Miami, Coral Gables, United States
| | - Robert W Fernandez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Jessica E Tanis
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Jacob C Brewer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Matthew S Creamer
- Interdepartmental Neuroscience Program, Yale University, New Haven, United States
| | - Michael R Koelle
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Interdepartmental Neuroscience Program, Yale University, New Haven, United States
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Ahmad W, Ebert PR. Metformin Attenuates Aβ Pathology Mediated Through Levamisole Sensitive Nicotinic Acetylcholine Receptors in a C. elegans Model of Alzheimer's Disease. Mol Neurobiol 2016; 54:5427-5439. [PMID: 27596506 DOI: 10.1007/s12035-016-0085-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/24/2016] [Indexed: 12/22/2022]
Abstract
The metabolic disease, type 2 diabetes mellitus (T2DM), is a major risk factor for Alzheimer's disease (AD). This suggests that drugs such as metformin that are used to treat T2DM may also be therapeutic toward AD and indicates an interaction between AD and energy metabolism. In this study, we have investigated the effects of metformin and another T2DM drug, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) in C. elegans expressing human Aβ42. We found that Aβ expressed in muscle inhibited levamisole sensitive nicotinic acetylcholine receptors and that metformin delayed Aβ-linked paralysis and improved acetylcholine neurotransmission in these animals. Metformin also moderated the effect of neuronal expression of Aβ: decreasing hypersensitivity to serotonin, restoring normal chemotaxis, and improving fecundity. Metformin was unable to overcome the small effect of neuronal Aβ on egg viability. The protective effects of metformin were associated with a decrease in the amount of toxic, oligomeric Aβ. AICAR has a similar protective effect against Aβ toxicity. This work supports the notion that anti-diabetes drugs and metabolic modulators may be effective against AD and that the worm model can be used to identify the specific interactions between Aβ and cellular proteins.
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Affiliation(s)
- Waqar Ahmad
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Paul R Ebert
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia.
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35
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Kim S, Kim H, Kralik JD, Jeong J. Vulnerability-Based Critical Neurons, Synapses, and Pathways in the Caenorhabditis elegans Connectome. PLoS Comput Biol 2016; 12:e1005084. [PMID: 27540747 PMCID: PMC4991803 DOI: 10.1371/journal.pcbi.1005084] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022] Open
Abstract
Determining the fundamental architectural design of complex nervous systems will lead to significant medical and technological advances. Yet it remains unclear how nervous systems evolved highly efficient networks with near optimal sharing of pathways that yet produce multiple distinct behaviors to reach the organism’s goals. To determine this, the nematode roundworm Caenorhabditis elegans is an attractive model system. Progress has been made in delineating the behavioral circuits of the C. elegans, however, many details are unclear, including the specific functions of every neuron and synapse, as well as the extent the behavioral circuits are separate and parallel versus integrative and serial. Network analysis provides a normative approach to help specify the network design. We investigated the vulnerability of the Caenorhabditis elegans connectome by performing computational experiments that (a) “attacked” 279 individual neurons and 2,990 weighted synaptic connections (composed of 6,393 chemical synapses and 890 electrical junctions) and (b) quantified the effects of each removal on global network properties that influence information processing. The analysis identified 12 critical neurons and 29 critical synapses for establishing fundamental network properties. These critical constituents were found to be control elements—i.e., those with the most influence over multiple underlying pathways. Additionally, the critical synapses formed into circuit-level pathways. These emergent pathways provide evidence for (a) the importance of backward locomotion, avoidance behavior, and social feeding behavior to the organism; (b) the potential roles of specific neurons whose functions have been unclear; and (c) both parallel and serial design elements in the connectome—i.e., specific evidence for a mixed architectural design. One of the most important scientific aims is to uncover the functional design principles of nervous systems. To reach this aim, it is useful to examine a complex nervous system that is both well specified and highly tractable, making the nematode roundworm Caenorhabditis elegans an attractive model system, especially since it is the only complete connectome currently available for analysis. In this computational study, we tested the effects of individual attacks on every neuron and synaptic connection in the C. elegans connectome to identify and characterize the most critical constituents of the network by quantifying the changes in key network properties of the connectome that influence information processing. Our analysis identified 12 neurons and 29 synapses critical to clustering, information integration and propagation. These critical constituents formed circuit-level structures that control network processing in the C. elegans connectome. We believe our study provides a significant advance in the understanding of the network topology of the C. elegans connectome, and provides insights into the fundamental architectural design of complex nervous systems.
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Affiliation(s)
- Seongkyun Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hyoungkyu Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jerald D. Kralik
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- * E-mail: (JDK); (JJ)
| | - Jaeseung Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Program of Brain and Cognitive Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- * E-mail: (JDK); (JJ)
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36
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Bermingham DP, Hardaway JA, Snarrenberg CL, Robinson SB, Folkes OM, Salimando GJ, Jinnah H, Blakely RD. Acute blockade of the Caenorhabditis elegans dopamine transporter DAT-1 by the mammalian norepinephrine transporter inhibitor nisoxetine reveals the influence of genetic modifications of dopamine signaling in vivo. Neurochem Int 2016; 98:122-8. [PMID: 26850478 DOI: 10.1016/j.neuint.2016.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/29/2016] [Accepted: 01/29/2016] [Indexed: 11/16/2022]
Abstract
Modulation of neurotransmission by the catecholamine dopamine (DA) is conserved across phylogeny. In the nematode Caenorhabditis elegans, excess DA signaling triggers Swimming-Induced Paralysis (Swip), a phenotype first described in animals with loss of function mutations in the presynaptic DA transporter (dat-1). Swip has proven to be a phenotype suitable for the identification of novel dat-1 mutations as well as the identification of novel genes that impact DA signaling. Pharmacological manipulations can also induce Swip, though the reagents employed to date lack specificity and potency, limiting their use in evaluation of dat-1 expression and function. Our lab previously established the mammalian norepinephrine transporter (NET) inhibitor nisoxetine to be a potent antagonist of DA uptake conferred by DAT-1 following heterologous expression. Here we demonstrate the ability of low (μM) concentrations of nisoxetine to trigger Swip within minutes of incubation, with paralysis dependent on DA release and signaling, and non-additive with Swip triggered by dat-1 deletion. Using nisoxetine in combination with genetic mutations that impact DA release, we further demonstrate the utility of the drug for demonstrating contributions of presynaptic DA receptors and ion channels to Swip. Together, these findings reveal nisoxetine as a powerful reagent for monitoring multiple dimensions of DA signaling in vivo, thus providing a new resource that can be used to evaluate contributions of dat-1 and other genes linked to DA signaling without the potential for compensations that attend constitutive genetic mutations.
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Affiliation(s)
- Daniel P Bermingham
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - J Andrew Hardaway
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Chelsea L Snarrenberg
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Sarah B Robinson
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Oakleigh M Folkes
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Greg J Salimando
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Hussain Jinnah
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA
| | - Randy D Blakely
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37240-7933, USA.
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37
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Kamaladevi A, Ganguli A, Balamurugan K. Lactobacillus casei stimulates phase-II detoxification system and rescues malathion-induced physiological impairments in Caenorhabditis elegans. Comp Biochem Physiol C Toxicol Pharmacol 2016; 179:19-28. [PMID: 26297616 DOI: 10.1016/j.cbpc.2015.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/05/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022]
Abstract
Malathion, an organophosphorus insecticide, is renowned for its inhibitory action on acetylcholinesterase (AChE) enzyme that eventually leads to widespread disturbance in the normal physiological and behavioral activities of any organism. Lactic acid bacteria (LAB) are still an underexploited and inexhaustible source of significant pharmaceutical thrust. In the present study, Caenorhabditis elegans was employed to identify and characterize the indigenous LAB isolated from different traditional food against malathion-induced toxicity. The results demonstrated that malathion at its LD50 concentration decreased various C. elegans physiological parameters such as survival, feeding, and locomotion. Among the screened isolates, L. casei exhibited an excellent protective efficacy against malathion-induced toxicity by increasing the level of AChE and thereby rescued all physiological parameters of C. elegans. In addition, short-term exposure and food choice assay divulged that L. casei could serve as a better food to protect C. elegans from noxious environment. The expression analysis unveiled that L. casei gavage upregulated the phase-II detoxification enzymes coding genes metallothioneins (mtl-1 and mtl-2) and glutathione-S-transferase (gst-8) and thereby eliminated malathion from the host system. Furthermore, the upregulation of ace-3 along with down-regulation of cyp35a in the nematodes supplemented with L. casei could be attributed to attenuate the malathion-induced physiological defects in C. elegans. Thus, the present study reports that an indigenous LAB-L. casei could serve as a promising protective agent against the harmful effects of pesticide.
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Affiliation(s)
- Arumugam Kamaladevi
- Department of Biotechnology, Alagappa University, Science campus, Karaikudi, Tamil Nadu, India
| | - Abhijit Ganguli
- Department of Biotechnology and Environmental Sciences, Thapar University, Patiala, Panjab, India
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38
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Zhao Y, Wu Q, Wang D. An epigenetic signal encoded protection mechanism is activated by graphene oxide to inhibit its induced reproductive toxicity in Caenorhabditis elegans. Biomaterials 2015; 79:15-24. [PMID: 26686978 DOI: 10.1016/j.biomaterials.2015.11.052] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/12/2015] [Accepted: 11/29/2015] [Indexed: 11/15/2022]
Abstract
Although many studies have suggested the adverse effects of engineered nanomaterials (ENMs), the self-protection mechanisms for organisms against ENMs toxicity are still largely unclear. Using Caenorhabditis elegans as an in vivo assay system, our results suggest the toxicity of graphene oxide in reducing reproductive capacity by inducing damage on gonad development. The observed reproductive toxicity of GO on gonad development was due to the combinational effect of germline apoptosis and cell cycle arrest, and DNA damage activation might act as an inducer for this combinational effect. For the underlying molecular mechanism of reproductive toxicity of GO, we raised a signaling cascade of HUS-1/CLK-2-CEP-1-EGL-1-CED-4-CED-3 to explain the roles of core apoptosis signaling pathway and DNA damage checkpoints. Moreover, we identified a miRNA regulation mechanism activated by GO to suppress its induced reproductive toxicity. A mir-360 regulation mechanism was activated by GO to suppress its induced DNA damage-apoptosis signaling cascade through affecting component of CEP-1. Our identified epigenetic signal encoded protection mechanism activated by GO suggests a novel self-protection mechanism for organisms against the ENMs toxicity.
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Affiliation(s)
- Yunli Zhao
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Qiuli Wu
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China.
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39
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Jadiya P, Fatima S, Baghel T, Mir SS, Nazir A. A Systematic RNAi Screen of Neuroprotective Genes Identifies Novel Modulators of Alpha-Synuclein-Associated Effects in Transgenic Caenorhabditis elegans. Mol Neurobiol 2015; 53:6288-6300. [PMID: 26567108 DOI: 10.1007/s12035-015-9517-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 10/28/2015] [Indexed: 12/17/2022]
Abstract
Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder, defined clinically by degeneration of dopaminergic neurons and the development of neuronal Lewy bodies. Current treatments of PD are inadequate due to a limited understanding of molecular events of the disease, thus calling for intense research efforts towards identification of novel therapeutic targets. We carried out the present studies towards identifying novel genetic modulators of PD-associated effects employing a transgenic Caenorhabditis elegans model expressing human alpha-synuclein. Employing a systematic RNA interference (RNAi)-based screening approach, we studied a set of neuroprotective genes of C. elegans with an aim of identifying genes that exhibit protective function under alpha-synuclein expression conditions. Our results reveal a novel set of alpha-synuclein effector genes that modulate alpha-synuclein aggregation and associated effects. The identified genes include those from various gene families including histone demethylase, lactate dehydrogenase, small ribosomal subunit SA protein, cytoskeletal protein, collapsin response mediator protein, and choline kinase. The functional characterization of these genes reveals involvement of signaling mechanisms such as Daf-16 and acetylcholine signaling. Further elucidation of mechanistic pathways associated with these genes will yield additional insights into mediators of alpha-synuclein-induced cytotoxicity and cell death, thereby helping in the identification of potential therapeutic targets for PD.
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Affiliation(s)
- Pooja Jadiya
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India.,Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Soobiya Fatima
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India.,Department of Bioengineering, Integral University, Kursi Road, Lucknow, 226 026, India
| | - Tanvi Baghel
- Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India
| | - Snober S Mir
- Department of Bioengineering, Integral University, Kursi Road, Lucknow, 226 026, India
| | - Aamir Nazir
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India. .,Laboratory of Functional Genomics and Molecular Toxicology, Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow, 226 031, India.
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Schumacher F, Chakraborty S, Kleuser B, Gulbins E, Schwerdtle T, Aschner M, Bornhorst J. Highly sensitive isotope-dilution liquid-chromatography-electrospray ionization-tandem-mass spectrometry approach to study the drug-mediated modulation of dopamine and serotonin levels in Caenorhabditis elegans. Talanta 2015; 144:71-9. [PMID: 26452793 PMCID: PMC4600537 DOI: 10.1016/j.talanta.2015.05.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/20/2015] [Accepted: 05/23/2015] [Indexed: 01/11/2023]
Abstract
Dopamine (DA) and serotonin (SRT) are monoamine neurotransmitters that play a key role in regulating the central and peripheral nervous system. Their impaired metabolism has been implicated in several neurological disorders, such as Parkinson's disease and depression. Consequently, it is imperative to monitor changes in levels of these low-abundant neurotransmitters and their role in mediating disease. For the first time, a rapid, specific and sensitive isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of DA and SRT in the nematode Caenorhabditis elegans (C. elegans). This model organism offers a unique approach for studying the effect of various drugs and environmental conditions on neurotransmitter levels, given by the conserved DA and SRT biology, including synaptic release, trafficking and formation. We introduce a novel sample preparation protocol incorporating the usage of sodium thiosulfate in perchloric acid as extraction medium that assures high recovery of the relatively unstable neurotransmitters monitored. Moreover, the use of both deuterated internal standards and the multiple reaction monitoring (MRM) technique allows for unequivocal quantification. Thereby, to the best of our knowledge, we achieve a detection sensitivity that clearly exceeds those of published DA and SRT quantification methods in various matrices. We are the first to show that exposure of C. elegans to the monoamine oxidase B (MAO-B) inhibitor selegiline or the catechol-O-methyltransferase (COMT) inhibitor tolcapone, in order to block DA and SRT degradation, resulted in accumulation of the respective neurotransmitter. Assessment of a behavioral output of the dopaminergic system (basal slowing response) corroborated the analytical LC-MS/MS data. Thus, utilization of the C. elegans model system in conjunction with our analytical method is well-suited to investigate drug-mediated modulation of the DA and SRT system in order to identify compounds with neuroprotective or regenerative properties.
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Affiliation(s)
- Fabian Schumacher
- Department of Toxicology, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany; Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany
| | - Sudipta Chakraborty
- Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Burkhard Kleuser
- Department of Toxicology, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany
| | - Tanja Schwerdtle
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Michael Aschner
- Department of Molecular Pharmacology, Neuroscience, and Pediatrics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Julia Bornhorst
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany.
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41
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Nidheesh T, Salim C, Rajini PS, Suresh PV. Antioxidant and neuroprotective potential of chitooligomers in Caenorhabditis elegans exposed to Monocrotophos. Carbohydr Polym 2015; 135:138-44. [PMID: 26453861 DOI: 10.1016/j.carbpol.2015.08.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/11/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022]
Abstract
The objectives of this investigation were to establish the propensity of the chitooligomers (COS) to ameliorate neurodegeneration and oxidative stress in Caenorhabditis elegans induced by an organophosphorus insecticide, Monocrotophos (MCP). COS was prepared from α-chitosan by the enzymatic method using chitosanase and characterized by HPLC and electron spray ionization-TOF-(ESI-TOF)-MS. We exposed age synchronized L4 C. elegans worms (both wild type N2 and transgenic strain BZ555 (Pdat-1:GFP) to sublethal concentration of MCP (0.75mM) for 24h in the presence or absence of COS (0.2mM). The neuroprotective effect of COS was examined in N2 worms in terms of brood size, lifespan, egg laying, dopamine content, acetylcholinesterase and carboxylesterase activity and by direct visualization and quantification of degeneration of dopaminergic neurons in BZ555. Exposure to COS extended lifespan, normalized egg laying, increased brood size, decreased the dopaminergic neurodegeneration, increased the dopamine content and increased AChE and carboxylesterase activity in C. elegans treated with MCP. COS induced a significant decrease in reactive oxygen species and increased the reduced glutathione level as well as increased superoxide dismutase and catalase activity. Our findings demonstrate that COS significantly inhibits the dopaminergic neurodegeneration and associated physiological alterations induced by MCP in C. elegans by attenuating the oxidative stress as well.
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Affiliation(s)
- T Nidheesh
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Department of Meat and Marine Sciences, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - Chinnu Salim
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Food Protectants and Infestation Control Department, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - P S Rajini
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Food Protectants and Infestation Control Department, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - P V Suresh
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Department of Meat and Marine Sciences, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India.
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Kalis AK, Kissiov DU, Kolenbrander ES, Palchick Z, Raghavan S, Tetreault BJ, Williams E, Loer CM, Wolff JR. Patterning of sexually dimorphic neurogenesis in the caenorhabditis elegans ventral cord by Hox and TALE homeodomain transcription factors. Dev Dyn 2014; 243:159-71. [PMID: 24115648 DOI: 10.1002/dvdy.24064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 09/16/2013] [Accepted: 09/16/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Reproduction in animals requires development of distinct neurons in each sex. In C. elegans, most ventral cord neurons (VCNs) are present in both sexes, with the exception of six hermaphrodite-specific neurons (VCs) and nine pairs of male-specific neurons (CAs and CPs) that arise from analogous precursor cells. How are the activities of sexual regulators and mediators of neuronal survival, division, and fate coordinated to generate sex-specificity in VCNs? RESULTS To address this, we have developed a toolkit of VCN markers that allows us to examine sex-specific neurogenesis, asymmetric fates of daughters of a neuroblast division, and regional specification on the anteroposterior axis. Here, we describe the roles of the Hox transcription factors LIN-39 and MAB-5 in promoting survival, differentiation, and regionalization of VCNs. We also find that the TALE class homeodomain proteins CEH-20 and UNC-62 contribute to specification of neurotransmitter fate in males. Furthermore, we identify that VCN sex is determined during the L1 larval stage. CONCLUSIONS These findings, combined with future analyses made possible by the suite of VCN markers described here, will elucidate how Hox-mediated cell fate decisions and sex determination intersect to influence development of neuronal sex differences.
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Salim C, Rajini PS. Glucose feeding during development aggravates the toxicity of the organophosphorus insecticide Monocrotophos in the nematode, Caenorhabditis elegans. Physiol Behav 2014; 131:142-8. [PMID: 24780411 DOI: 10.1016/j.physbeh.2014.04.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/08/2014] [Indexed: 12/12/2022]
Abstract
Several studies have demonstrated that high glucose feeding induced oxidative stress and apoptosis thereby affecting growth, fertility, aging and lifespan in Caenorhabditis elegans. Earlier studies from our laboratory had clearly established the propensity of monocrotophos, an OPI to alter the physiological and behavioral responses of C. elegans. The present study was aimed to investigate the effect of monocrotophos (MCP) on physiological/behavioral and biochemical responses in C. elegans that were maintained on high glucose diet. We exposed the worms through development to high glucose diet (2%) and then treated with sublethal concentrations of MCP (0.5, 0.75, 1.5mM). We measured the behavioral responses in terms of locomotion, physiological responses in terms of egg laying, brood size, lifespan; morphological alterations; and biochemical responses including glucose content. The worms exposed from egg stage through development to high glucose diet showed enhanced toxic outcome of MCP in terms of physiological, behavioral and biochemical responses. Our studies showed that C. elegans is a good model to study glucose-OPI interactive neurotoxicity since all the responses could be studied at ease in this organism and the outcome could be well extrapolated to those that one would expect in higher animals.
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Affiliation(s)
- Chinnu Salim
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India; Food Protectants and Infestation Control Department, CSIR-Central Food Technological Research Institute, Mysore 570020, India
| | - P S Rajini
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi, India; Food Protectants and Infestation Control Department, CSIR-Central Food Technological Research Institute, Mysore 570020, India.
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Kearn J, Ludlow E, Dillon J, O'Connor V, Holden-Dye L. Fluensulfone is a nematicide with a mode of action distinct from anticholinesterases and macrocyclic lactones. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2014; 109:44-57. [PMID: 24581383 DOI: 10.1016/j.pestbp.2014.01.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 06/03/2023]
Abstract
Plant parasitic nematodes infest crops and present a threat to food security worldwide. Currently available chemical controls e.g. methyl bromide, organophosphates and carbamates have an unacceptable level of toxicity to non-target organisms and are being withdrawn from use. Fluensulfone is a new nematicide of the fluoroalkenyl thioether group that has significantly reduced environmental impact with low toxicity to non-target insects and mammals. Here, we show that the model genetic organism Caenorhabditis elegans is susceptible to the irreversible nematicidal effects of fluensulfone. Whilst the dose required is higher than that which has nematicidal activity against Meloidogyne spp. the profile of effects on motility, egg-hatching and survival is similar to that reported for plant parasitic nematodes. C. elegans thus provides a tractable experimental paradigm to analyse the effects of fluensulfone on nematode behaviour. We find that fluensulfone has pleiotropic actions and inhibits development, egg-laying, egg-hatching, feeding and locomotion. In the case of feeding and locomotion, an early excitation precedes the gross inhibition. The profile of these effects is notably distinct from other classes of anthelmintic and nematicide: the inhibition of motility caused by fluensulfone is not accompanied by the hypercontraction which is characteristic of organophosphates and carbamates and C. elegans mutants that are resistant to the carbamate aldicarb and the macrocyclic lactone ivermectin retain susceptibility to fluensulfone. These data indicate fluensulfone's mode of action is distinct from currently available nematicides and it therefore presents a promising new chemical entity for crop protection.
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Affiliation(s)
- James Kearn
- Centre for Biological Sciences, University of Southampton, Building 85, University Road, Southampton SO17 1BJ, United Kingdom
| | - Elizabeth Ludlow
- Centre for Biological Sciences, University of Southampton, Building 85, University Road, Southampton SO17 1BJ, United Kingdom
| | - James Dillon
- Centre for Biological Sciences, University of Southampton, Building 85, University Road, Southampton SO17 1BJ, United Kingdom
| | - Vincent O'Connor
- Centre for Biological Sciences, University of Southampton, Building 85, University Road, Southampton SO17 1BJ, United Kingdom
| | - Lindy Holden-Dye
- Centre for Biological Sciences, University of Southampton, Building 85, University Road, Southampton SO17 1BJ, United Kingdom.
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Zheng C, Karimzadegan S, Chiang V, Chalfie M. Histone methylation restrains the expression of subtype-specific genes during terminal neuronal differentiation in Caenorhabditis elegans. PLoS Genet 2013; 9:e1004017. [PMID: 24348272 PMCID: PMC3861114 DOI: 10.1371/journal.pgen.1004017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/25/2013] [Indexed: 01/16/2023] Open
Abstract
Although epigenetic control of stem cell fate choice is well established, little is known about epigenetic regulation of terminal neuronal differentiation. We found that some differences among the subtypes of Caenorhabditis elegans VC neurons, particularly the expression of the transcription factor gene unc-4, require histone modification, most likely H3K9 methylation. An EGF signal from the vulva alleviated the epigenetic repression of unc-4 in vulval VC neurons but not the more distant nonvulval VC cells, which kept unc-4 silenced. Loss of the H3K9 methyltransferase MET-2 or H3K9me2/3 binding proteins HPL-2 and LIN-61 or a novel chromodomain protein CEC-3 caused ectopic unc-4 expression in all VC neurons. Downstream of the EGF signaling in vulval VC neurons, the transcription factor LIN-11 and histone demethylases removed the suppressive histone marks and derepressed unc-4. Behaviorally, expression of UNC-4 in all the VC neurons caused an imbalance in the egg-laying circuit. Thus, epigenetic mechanisms help establish subtype-specific gene expression, which are needed for optimal activity of a neural circuit.
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Affiliation(s)
- Chaogu Zheng
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Siavash Karimzadegan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Victor Chiang
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
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Gardner M, Rosell M, Myers EM. Measuring the effects of bacteria on C. elegans behavior using an egg retention assay. J Vis Exp 2013:e51203. [PMID: 24192811 PMCID: PMC3948155 DOI: 10.3791/51203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
C. elegans egg-laying behavior is affected by environmental cues such as osmolarity and vibration. In the total absence of food C. elegans also cease egg-laying and retain fertilized eggs in their uterus. However, the effect of different sources of food, especially pathogenic bacteria and particularly Enterococcus faecalis, on egg-laying behavior is not well characterized. The egg-in-worm (EIW) assay is a useful tool to quantify the effects of different types of bacteria, in this case E. faecalis, on egg- laying behavior. EIW assays involve counting the number of eggs retained in the uterus of C. elegans. The EIW assay involves bleaching staged, gravid adult C. elegans to remove the cuticle and separate the retained eggs from the animal. Prior to bleaching, worms are exposed to bacteria (or any type of environmental cue) for a fixed period of time. After bleaching, one is very easily able to count the number of eggs retained inside the uterus of the worms. In this assay, a quantifiable increase in egg retention after E. faecalis exposure can be easily measured. The EIW assay is a behavioral assay that may be used to screen for potentially pathogenic bacteria or the presence of environmental toxins. In addition, the EIW assay may be a tool to screen for drugs that affect neurotransmitter signaling since egg-laying behavior is modulated by neurotransmitters such as serotonin and acetylcholine.
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Affiliation(s)
- Mona Gardner
- Department of Biological and Allied Health Sciences, Fairleigh Dickinson University
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Leelaja BC, Rajini PS. Biochemical and physiological responses in Caenorhabditis elegans exposed to sublethal concentrations of the organophosphorus insecticide, monocrotophos. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2013; 94:8-13. [PMID: 23683899 DOI: 10.1016/j.ecoenv.2013.04.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 06/02/2023]
Abstract
The objective of this study was to investigate the impact of sublethal concentrations of MCP on definitive markers of toxicity and oxidative balance in the nematode, Caenorhabditis elegans. Exposure of worms to 0.85, 1.7 and 3.4mM (1/40, 1/20 and 1/10 LC50; LC50=34 mM) for 4h at 20°C induced significant perturbations in physiological parameters such as decreased brood size (47-73%), increased paralysis (47-85%) and inhibition of the activities of acetylcholinesterase (75-86%) and carboxylesterase (76-81%). These changes were accompanied by distinct oxidative impairments as evidenced by increased reactive oxygen species, decline in glutathione content and decrease in superoxide dismutase activity. Our results clearly demonstrate that low concentrations of MCP may alter the physiological and biochemical status in the nematode, thereby affecting the organism's fitness. Our findings on C. elegans provide an easy diagnosis for OPI contamination and may become helpful in evaluating the ecotoxicological effects of OPI in the aquatic environment near agricultural fields.
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Affiliation(s)
- Bhadravathi Chandrappa Leelaja
- Food Protectants and Infestation Control Department, CSIR-Central Food Technological Research Institute, Mysore 570020, India
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Genetic interactions between UNC-17/VAChT and a novel transmembrane protein in Caenorhabditis elegans. Genetics 2012; 192:1315-25. [PMID: 23051648 DOI: 10.1534/genetics.112.145771] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The unc-17 gene encodes the vesicular acetylcholine transporter (VAChT) in Caenorhabditis elegans. unc-17 reduction-of-function mutants are small, slow growing, and uncoordinated. Several independent unc-17 alleles are associated with a glycine-to-arginine substitution (G347R), which introduces a positive charge in the ninth transmembrane domain (TMD) of UNC-17. To identify proteins that interact with UNC-17/VAChT, we screened for mutations that suppress the uncoordinated phenotype of UNC-17(G347R) mutants. We identified several dominant allele-specific suppressors, including mutations in the sup-1 locus. The sup-1 gene encodes a single-pass transmembrane protein that is expressed in a subset of neurons and in body muscles. Two independent suppressor alleles of sup-1 are associated with a glycine-to-glutamic acid substitution (G84E), resulting in a negative charge in the SUP-1 TMD. A sup-1 null mutant has no obvious deficits in cholinergic neurotransmission and does not suppress unc-17 mutant phenotypes. Bimolecular fluorescence complementation (BiFC) analysis demonstrated close association of SUP-1 and UNC-17 in synapse-rich regions of the cholinergic nervous system, including the nerve ring and dorsal nerve cords. These observations suggest that UNC-17 and SUP-1 are in close proximity at synapses. We propose that electrostatic interactions between the UNC-17(G347R) and SUP-1(G84E) TMDs alter the conformation of the mutant UNC-17 protein, thereby restoring UNC-17 function; this is similar to the interaction between UNC-17/VAChT and synaptobrevin.
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Hsu PCL, O'Callaghan M, Al-Salim N, Hurst MRH. Quantum dot nanoparticles affect the reproductive system of Caenorhabditis elegans. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:2366-2374. [PMID: 22847876 DOI: 10.1002/etc.1967] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/31/2012] [Accepted: 06/14/2012] [Indexed: 06/01/2023]
Abstract
Quantum dots (QDs) are an increasingly important class of nanoparticle, but little ecotoxicological data for QDs has been published to date. The effects of mercaptosuccinic acid (MSA)-capped QDs (QDs-MSA) and equivalent concentrations of cadmium (Cd) from cadmium chloride on growth and reproduction of the nematode Caenorhabditis elegans (Rhabditidae) were assessed in laboratory experiments. Growth from larvae to adults of C. elegans was unaffected by exposure to 1 µM fluorescent QDs-MSA, but adults produced more embryos and laid them prematurely. Furthermore, C. elegans exposed to QDs-MSA (1 µM) showed a high percentage of embryo mortality (19.2 ± 0.5, p < 0.001, percentage ± standard deviation) compared with unexposed nematodes (11.6 ± 0.4). An egg-laying defect phenotype was also observed at high frequency in response to 1 µM QDs-MSA exposure (38.3 ± 3.6%, p < 0.01; control 10.0 ± 2.2%). This resulted in a reduced mean life span (20.5 ± 1.1 d, p < 0.05) compared with the control (24.6 ± 1.0 d). Cadmium also caused reduced life span in C. elegans, but a low incidence of egg-laying defects was observed, suggesting that Cd and QDs-MSA affected C. elegans by different mechanisms. Furthermore, egg-laying defects caused by QDs-MSA responded to the addition of the anticonvulsant ethosuximide and to a lesser extent to the neurotransmitter serotonin, suggesting that QDs-MSA might have disrupted motor neurons during the reproduction process.
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50
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Zhang Y, Chen D, Ennis AC, Polli JR, Xiao P, Zhang B, Stellwag EJ, Overton A, Pan X. Chemical dispersant potentiates crude oil impacts on growth, reproduction, and gene expression in Caenorhabditis elegans. Arch Toxicol 2012; 87:371-82. [PMID: 22990136 DOI: 10.1007/s00204-012-0936-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/28/2012] [Indexed: 01/09/2023]
Abstract
The economic, environmental, and human health impacts of the deepwater horizon (DWH) oil spill have been of significant concern in the general public and among scientists. This study employs parallel experiments to test the effects of crude oil from the DWH oil well, chemical dispersant Corexit 9500A, and dispersant-oil mixture on growth and reproduction in the model organism Caenorhabditis elegans. Both the crude oil and the dispersant significantly inhibited the reproduction of C. elegans. Dose-dependent inhibitions of hatched larvae production were observed in worms exposed to both crude oil and dispersant. Importantly, the chemical dispersant Corexit 9500A potentiated crude oil effects; dispersant-oil mixture induced more significant effects than oil or dispersant-alone exposures. While oil-alone exposure and dispersant-alone exposure have none to moderate inhibitory effects on hatched larvae production, respectively, the mixture of dispersant and oil induced much more significant inhibition of offspring production. The production of hatched larvae was almost completely inhibited by several high concentrations of the dispersant-oil mixture. This suggests a sensitive bioassay for future investigation of oil/dispersant impacts on organisms. We also investigated the effects of crude oil/dispersant exposure at the molecular level by measuring the expressions of 31 functional genes. Results showed that the dispersant and the dispersant-oil mixture induced aberrant expressions of 12 protein-coding genes (cat-4, trxr-2, sdhb-1, lev-8, lin-39, unc-115, prdx-3, sod-1, acr-16, ric-3, unc-68, and acr-8). These 12 genes are associated with a variety of biological processes, including egg-laying, oxidative stress, muscle contraction, and neurological functions. In summary, the toxicity potentiating effect of chemical dispersant must be taken into consideration in future crude oil cleanup applications.
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Affiliation(s)
- Yanqiong Zhang
- Department of Biology, East Carolina University, N108 Howell Science Complex, Greenville, NC 27858, USA
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