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Cornell R, Cao W, Harradine B, Godini R, Handley A, Pocock R. Neuro-intestinal acetylcholine signalling regulates the mitochondrial stress response in Caenorhabditis elegans. Nat Commun 2024; 15:6594. [PMID: 39097618 PMCID: PMC11297972 DOI: 10.1038/s41467-024-50973-y] [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: 03/20/2024] [Accepted: 07/25/2024] [Indexed: 08/05/2024] Open
Abstract
Neurons coordinate inter-tissue protein homeostasis to systemically manage cytotoxic stress. In response to neuronal mitochondrial stress, specific neuronal signals coordinate the systemic mitochondrial unfolded protein response (UPRmt) to promote organismal survival. Yet, whether chemical neurotransmitters are sufficient to control the UPRmt in physiological conditions is not well understood. Here, we show that gamma-aminobutyric acid (GABA) inhibits, and acetylcholine (ACh) promotes the UPRmt in the Caenorhabditis elegans intestine. GABA controls the UPRmt by regulating extra-synaptic ACh release through metabotropic GABAB receptors GBB-1/2. We find that elevated ACh levels in animals that are GABA-deficient or lack ACh-degradative enzymes induce the UPRmt through ACR-11, an intestinal nicotinic α7 receptor. This neuro-intestinal circuit is critical for non-autonomously regulating organismal survival of oxidative stress. These findings establish chemical neurotransmission as a crucial regulatory layer for nervous system control of systemic protein homeostasis and stress responses.
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Affiliation(s)
- Rebecca Cornell
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Wei Cao
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Bernie Harradine
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Rasoul Godini
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Ava Handley
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia.
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2
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Gadhia A, Barker E, Morgan A, Barclay JW. Functional analysis of epilepsy-associated GABA A receptor mutations using Caenorhabditis elegans. Epilepsia Open 2024; 9:1458-1466. [PMID: 38813985 PMCID: PMC11296113 DOI: 10.1002/epi4.12982] [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: 01/24/2024] [Revised: 05/03/2024] [Accepted: 05/18/2024] [Indexed: 05/31/2024] Open
Abstract
OBJECTIVE GABAA receptor subunit mutations pose a significant risk for genetic generalized epilepsy; however, there are over 150 identified variants, many with unknown or unvalidated pathogenicity. We aimed to develop in vivo models for testing GABAA receptor variants using the model organism, Caenorhabditis elegans. METHODS CRISPR-Cas9 gene editing was used to create a complete deletion of unc-49, a C. elegans GABAA receptor, and to create homozygous epilepsy-associated mutations in the endogenous unc-49 gene. The unc-49 deletion strain was rescued with transgenes for either the C. elegans unc-49B subunit or the α1, β3, and γ2 subunits for the human GABAA receptor. All newly created strains were analyzed for phenotype and compared against existing unc-49 mutations. RESULTS Nematodes with a full genetic deletion of the entire unc-49 locus were compared with existing unc-49 mutations in three separate phenotypic assays-coordinated locomotion, shrinker frequency and seizure-like convulsions. The full unc-49 deletion exhibited reduced locomotion and increased shrinker frequency and PTZ-induced convulsions, but were not found to be phenotypically stronger than existing unc-49 mutations. Rescue with the unc-49B subunit or creation of humanized worms for the GABAA receptor both showed partial phenotypic rescue for all three phenotypes investigated. Finally, two epilepsy-associated variants were analyzed and deemed to be loss of function, thus validating their pathogenicity. SIGNIFICANCE These findings establish C. elegans as a genetic model to investigate GABAA receptor mutations and delineate a platform for validating associated variants in any epilepsy-associated gene. PLAIN LANGUAGE SUMMARY Epilepsy is a complex human disease that can be caused by mutations in specific genes. Many possible mutations have been identified, but it is unknown for most of them whether they cause the disease. We tested the role of mutations in one specific gene using a small microscopic worm as an animal model. Our results establish this worm as a model for epilepsy and confirm that the two unknown mutations are likely to cause the disease.
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Affiliation(s)
- Ami Gadhia
- Department of Biochemistry, Cell and Systems Biology, ISMIBUniversity of LiverpoolLiverpoolUK
| | - Eleanor Barker
- Department of Biochemistry, Cell and Systems Biology, ISMIBUniversity of LiverpoolLiverpoolUK
| | - Alan Morgan
- Department of Biochemistry, Cell and Systems Biology, ISMIBUniversity of LiverpoolLiverpoolUK
| | - Jeff W. Barclay
- Department of Biochemistry, Cell and Systems Biology, ISMIBUniversity of LiverpoolLiverpoolUK
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3
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Yue Z, Li Y, Yu B, Xu Y, Chen L, Chitturi J, Meng J, Wang Y, Tian Y, Mouridi SE, Zhang C, Zhen M, Boulin T, Gao S. A leak K + channel TWK-40 sustains the rhythmic motor program. PNAS NEXUS 2024; 3:pgae234. [PMID: 38957449 PMCID: PMC11217676 DOI: 10.1093/pnasnexus/pgae234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Leak potassium (K+) currents, conducted by two-pore domain K+ (K2P) channels, are critical for the stabilization of the membrane potential. The effect of K2P channels on motor rhythm remains enigmatic. We show here that the K2P TWK-40 contributes to the rhythmic defecation motor program (DMP) in Caenorhabditis elegans. Disrupting TWK-40 suppresses the expulsion defects of nlp-40 and aex-2 mutants. By contrast, a gain-of-function (gf) mutant of twk-40 significantly reduces the expulsion frequency per DMP cycle. In situ whole-cell patch clamping demonstrates that TWK-40 forms an outward current that hyperpolarize the resting membrane potential of dorsorectal ganglion ventral process B (DVB), an excitatory GABAergic motor neuron that activates expulsion muscle contraction. In addition, TWK-40 substantially contributes to the rhythmic activity of DVB. Specifically, DVB Ca2+ oscillations exhibit obvious defects in loss-of-function (lf) mutant of twk-40. Expression of TWK-40(gf) in DVB recapitulates the expulsion deficiency of the twk-40(gf) mutant, and inhibits DVB Ca2+ oscillations in both wild-type and twk-40(lf) animals. Moreover, DVB innervated enteric muscles also exhibit rhythmic Ca2+ defects in twk-40 mutants. In summary, these findings establish TWK-40 as a crucial neuronal stabilizer of DMP, linking leak K2P channels with rhythmic motor activity.
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Affiliation(s)
- Zhongpu Yue
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yi Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bin Yu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yueqing Xu
- College of Biomedical Engineering, South-Central University for Nationalities, Wuhan 430074, China
| | - Lili Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jyothsna Chitturi
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Jun Meng
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Ying Wang
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Yuhang Tian
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sonia El Mouridi
- Univ Lyon, Université Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal 23955–6900, Kingdom of Saudi Arabia
| | - Cuntai Zhang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Thomas Boulin
- Univ Lyon, Université Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, Lyon 69008, France
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Lei M, Tan Y, Ke J, Wang M, He Z, Ou G, Tu H, Tan W. Loss of cilia in chemosensory neurons inhibits pathogen avoidance in Caenorhabditis elegans. Microbes Infect 2024:105370. [PMID: 38843949 DOI: 10.1016/j.micinf.2024.105370] [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: 02/11/2024] [Revised: 05/29/2024] [Accepted: 05/30/2024] [Indexed: 06/16/2024]
Abstract
Pathogen avoidance is a crucial and evolutionarily conserved behavior that enhances survival by preventing infection in diverse species, including Caenorhabditis elegans (C. elegans). This behavior relies on multiple chemosensory neurons equipped with cilia that are exposed to the external environment. However, the specific role of neuronal cilia in pathogen avoidance has not been completely elucidated. Herein, we discovered that osm-3(p802) mutants, which lack chemosensory neuronal cilia, exhibit slower avoidance of the pathogen Pseudomonas aeruginosa PA14, but not Escherichia coli OP50. This observation was consistent when osm-3(p802) mutants were exposed to P. aeruginosa PAO1. Following an encounter with PA14, the pumping, thrashing, and defecation behaviors of osm-3 mutants were comparable to those of the wild-type. However, the osm-3 mutants demonstrated reduced intestinal colonization of PA14, suggesting that they have stronger intestinal clearance ability. We conducted RNA-seq to identify genes responding to external stimuli that were differentially expressed owing to the loss of osm-3 and PA14 infection. Using RNAi, we demonstrated that three of these genes were essential for normal pathogen avoidance. In conclusion, our findings demonstrate that the loss of chemosensory neuronal cilia reduces pathogen avoidance in C. elegans while delaying intestinal colonization.
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Affiliation(s)
- Ming Lei
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China; The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Yanheng Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Jingyi Ke
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Mengqi Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Zeyang He
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
| | - Guangshuo Ou
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China.
| | - Weihong Tan
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China; The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, China.
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5
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Rosano G, Barzasi A, Lynagh T. Loss of activation by GABA in vertebrate delta ionotropic glutamate receptors. Proc Natl Acad Sci U S A 2024; 121:e2313853121. [PMID: 38285949 PMCID: PMC10861852 DOI: 10.1073/pnas.2313853121] [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: 08/23/2023] [Accepted: 12/27/2023] [Indexed: 01/31/2024] Open
Abstract
Ionotropic glutamate receptors (iGluRs) mediate excitatory signals between cells by binding neurotransmitters and conducting cations across the cell membrane. In the mammalian brain, most of these signals are mediated by two types of iGluRs: AMPA and NMDA (i.e. iGluRs sensitive to 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid and N-methyl-D-aspartic acid, respectively). Delta-type iGluRs of mammals also form neurotransmitter-binding channels in the cell membrane, but in contrast, their channel is not activated by neurotransmitter binding, raising biophysical questions about iGluR activation and biological questions about the role of delta iGluRs. We therefore investigated the divergence of delta iGluRs from their iGluR cousins using molecular phylogenetics, electrophysiology, and site-directed mutagenesis. We find that delta iGluRs are found in numerous bilaterian animals (e.g., worms, starfish, and vertebrates) and are closely related to AMPA receptors, both genetically and functionally. Surprisingly, we observe that many iGluRs of the delta family are activated by the classical inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Finally, we identify nine amino acid substitutions that likely gave rise to the inactivity of today's mammalian delta iGluRs, and these mutations abolish activity when engineered into active invertebrate delta iGluRs, partly by inducing receptor desensitization. These results offer biophysical insight into iGluR activity and point to a role for GABA in excitatory signaling in invertebrates.
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Affiliation(s)
- Giulio Rosano
- Michael Sars Centre, University of Bergen, Bergen5008, Norway
| | - Allan Barzasi
- Michael Sars Centre, University of Bergen, Bergen5008, Norway
| | - Timothy Lynagh
- Michael Sars Centre, University of Bergen, Bergen5008, Norway
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6
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Li Y, Chitturi J, Yu B, Zhang Y, Wu J, Ti P, Hung W, Zhen M, Gao S. UBR-1 ubiquitin ligase regulates the balance between GABAergic and glutamatergic signaling. EMBO Rep 2023; 24:e57014. [PMID: 37811674 PMCID: PMC10626437 DOI: 10.15252/embr.202357014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 10/10/2023] Open
Abstract
Excitation/inhibition (E/I) balance is carefully maintained by the nervous system. The neurotransmitter GABA has been reported to be co-released with its sole precursor, the neurotransmitter glutamate. The genetic and circuitry mechanisms to establish the balance between GABAergic and glutamatergic signaling have not been fully elucidated. Caenorhabditis elegans DVB is an excitatory GABAergic motoneuron that drives the expulsion step in the defecation motor program. We show here that in addition to UNC-47, the vesicular GABA transporter, DVB also expresses EAT-4, a vesicular glutamate transporter. UBR-1, a conserved ubiquitin ligase, regulates DVB activity by suppressing a bidirectional inhibitory glutamate signaling. Loss of UBR-1 impairs DVB Ca2+ activity and expulsion frequency. These impairments are fully compensated by the knockdown of EAT-4 in DVB. Further, glutamate-gated chloride channels GLC-3 and GLC-2/4 receive DVB's glutamate signals to inhibit DVB and enteric muscle activity, respectively. These results implicate an intrinsic cellular mechanism that promotes the inherent asymmetric neural activity. We propose that elevated glutamate in ubr-1 mutants, being the cause of the E/I shift, potentially contributes to Johanson Blizzard syndrome.
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Affiliation(s)
- Yi Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Jyothsna Chitturi
- Lunenfeld‐Tanenbaum Research Institute, Mount Sinai HospitalUniversity of TorontoTorontoONCanada
| | - Bin Yu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Yongning Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Jing Wu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Panpan Ti
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Wesley Hung
- Lunenfeld‐Tanenbaum Research Institute, Mount Sinai HospitalUniversity of TorontoTorontoONCanada
| | - Mei Zhen
- Lunenfeld‐Tanenbaum Research Institute, Mount Sinai HospitalUniversity of TorontoTorontoONCanada
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
- Key Laboratory of Vascular Aging of the Ministry of Education, Tongji Hospital of Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
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7
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Zhang X, Wang Y, Cai Z, Wan Z, Aihemaiti Y, Tu H. A gonadal gap junction INX-14/Notch GLP-1 signaling axis suppresses gut defense through an intestinal lysosome pathway. Front Immunol 2023; 14:1249436. [PMID: 37928537 PMCID: PMC10620905 DOI: 10.3389/fimmu.2023.1249436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Gap junctions mediate intercellular communications across cellular networks in the nervous and immune systems. Yet their roles in intestinal innate immunity are poorly understood. Here, we show that the gap junction/innexin subunit inx-14 acts in the C. elegans gonad to attenuate intestinal defenses to Pseudomonas aeruginosa PA14 infection through the PMK-1/p38 pathway. RNA-Seq analyses revealed that germline-specific inx-14 RNAi downregulated Notch/GLP-1 signaling, while lysosome and PMK-1/p38 pathways were upregulated. Consistently, disruption of inx-14 or glp-1 in the germline enhanced resistance to PA14 infection and upregulated lysosome and PMK-1/p38 activity. We show that lysosome signaling functions downstream of the INX-14/GLP-1 signaling axis and upstream of PMK-1/p38 pathway to facilitate intestinal defense. Our findings expand the understanding of the links between the reproductive system and intestinal defense, which may be evolutionarily conserved in higher organism.
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Affiliation(s)
| | | | | | | | | | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
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8
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Choi U, Hu M, Zhang Q, Sieburth D. The head mesodermal cell couples FMRFamide neuropeptide signaling with rhythmic muscle contraction in C. elegans. Nat Commun 2023; 14:4218. [PMID: 37452027 PMCID: PMC10349088 DOI: 10.1038/s41467-023-39955-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
FMRFamides are evolutionarily conserved neuropeptides that play critical roles in behavior, energy balance, and reproduction. Here, we show that FMRFamide signaling from the nervous system is critical for the rhythmic activation of a single cell of previously unknown function, the head mesodermal cell (hmc) in C. elegans. Behavioral, calcium imaging, and genetic studies reveal that release of the FLP-22 neuropeptide from the AVL neuron in response to pacemaker signaling activates hmc every 50 s through an frpr-17 G protein-coupled receptor (GPCR) and a protein kinase A signaling cascade in hmc. hmc activation results in muscle contraction through coupling by gap junctions composed of UNC-9/Innexin. hmc activation is inhibited by the neuronal release of a second FMRFamide-like neuropeptide, FLP-9, which functions through its GPCR, frpr-21, in hmc. This study reveals a function for two opposing FMRFamide signaling pathways in controlling the rhythmic activation of a target cell through volume transmission.
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Affiliation(s)
- Ukjin Choi
- DSR graduate program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Mingxi Hu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Qixin Zhang
- MPHY program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
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9
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Liu J, Zhang P, Zheng Z, Afridi MI, Zhang S, Wan Z, Zhang X, Stingelin L, Wang Y, Tu H. GABAergic signaling between enteric neurons and intestinal smooth muscle promotes innate immunity and gut defense in Caenorhabditis elegans. Immunity 2023; 56:1515-1532.e9. [PMID: 37437538 DOI: 10.1016/j.immuni.2023.06.004] [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: 08/16/2022] [Revised: 03/06/2023] [Accepted: 06/07/2023] [Indexed: 07/14/2023]
Abstract
The nervous system is critical for intestinal homeostasis and function, but questions remain regarding its impact on gut immune defense. By screening the major neurotransmitters of C. elegans, we found that γ-aminobutyric acid (GABA) deficiency enhanced susceptibility to pathogenic Pseudomonas aeruginosa PA14 infection. GABAergic signaling between enteric neurons and intestinal smooth muscle promoted gut defense in a PMK-1/p38-dependent, but IIS/DAF-16- and DBL-1/TGF-β-independent, pathway. Transcriptomic profiling revealed that the neuropeptide, FLP-6, acted downstream of enteric GABAergic signaling. Further data determined that FLP-6 was expressed and secreted by intestinal smooth muscle cells and functioned as a paracrine molecule on the intestinal epithelium. FLP-6 suppressed the transcription factors ZIP-10 and KLF-1 that worked in parallel and converged to the PMK-1/p38 pathway in the intestinal epithelia for innate immunity and gut defense. Collectively, these findings uncover an enteric neuron-muscle-epithelium axis that may be evolutionarily conserved in higher organisms.
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Affiliation(s)
- Junqiang Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Pei Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Zhongfan Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Muhammad Irfan Afridi
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Shan Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Zhiqing Wan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Xiumei Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Lukas Stingelin
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Yirong Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China
| | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China.
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10
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Kenis S, Istiban MN, Van Damme S, Vandewyer E, Watteyne J, Schoofs L, Beets I. Ancestral glycoprotein hormone-receptor pathway controls growth in C. elegans. Front Endocrinol (Lausanne) 2023; 14:1200407. [PMID: 37409228 PMCID: PMC10319355 DOI: 10.3389/fendo.2023.1200407] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 05/23/2023] [Indexed: 07/07/2023] Open
Abstract
In vertebrates, thyrostimulin is a highly conserved glycoprotein hormone that, besides thyroid stimulating hormone (TSH), is a potent ligand of the TSH receptor. Thyrostimulin is considered the most ancestral glycoprotein hormone and orthologs of its subunits, GPA2 and GPB5, are widely conserved across vertebrate and invertebrate animals. Unlike TSH, however, the functions of the thyrostimulin neuroendocrine system remain largely unexplored. Here, we identify a functional thyrostimulin-like signaling system in Caenorhabditis elegans. We show that orthologs of GPA2 and GPB5, together with thyrotropin-releasing hormone (TRH) related neuropeptides, constitute a neuroendocrine pathway that promotes growth in C. elegans. GPA2/GPB5 signaling is required for normal body size and acts through activation of the glycoprotein hormone receptor ortholog FSHR-1. C. elegans GPA2 and GPB5 increase cAMP signaling by FSHR-1 in vitro. Both subunits are expressed in enteric neurons and promote growth by signaling to their receptor in glial cells and the intestine. Impaired GPA2/GPB5 signaling causes bloating of the intestinal lumen. In addition, mutants lacking thyrostimulin-like signaling show an increased defecation cycle period. Our study suggests that the thyrostimulin GPA2/GPB5 pathway is an ancient enteric neuroendocrine system that regulates intestinal function in ecdysozoans, and may ancestrally have been involved in the control of organismal growth.
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Affiliation(s)
- Signe Kenis
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Majdulin Nabil Istiban
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Sara Van Damme
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Elke Vandewyer
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Jan Watteyne
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Liliane Schoofs
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Isabel Beets
- Neural Signaling and Circuit Plasticity Group, Department of Biology, KU Leuven, Leuven, Belgium
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11
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Bergs ACF, Liewald JF, Rodriguez-Rozada S, Liu Q, Wirt C, Bessel A, Zeitzschel N, Durmaz H, Nozownik A, Dill H, Jospin M, Vierock J, Bargmann CI, Hegemann P, Wiegert JS, Gottschalk A. All-optical closed-loop voltage clamp for precise control of muscles and neurons in live animals. Nat Commun 2023; 14:1939. [PMID: 37024493 PMCID: PMC10079764 DOI: 10.1038/s41467-023-37622-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
Excitable cells can be stimulated or inhibited by optogenetics. Since optogenetic actuation regimes are often static, neurons and circuits can quickly adapt, allowing perturbation, but not true control. Hence, we established an optogenetic voltage-clamp (OVC). The voltage-indicator QuasAr2 provides information for fast, closed-loop optical feedback to the bidirectional optogenetic actuator BiPOLES. Voltage-dependent fluorescence is held within tight margins, thus clamping the cell to distinct potentials. We established the OVC in muscles and neurons of Caenorhabditis elegans, and transferred it to rat hippocampal neurons in slice culture. Fluorescence signals were calibrated to electrically measured potentials, and wavelengths to currents, enabling to determine optical I/V-relationships. The OVC reports on homeostatically altered cellular physiology in mutants and on Ca2+-channel properties, and can dynamically clamp spiking in C. elegans. Combining non-invasive imaging with control capabilities of electrophysiology, the OVC facilitates high-throughput, contact-less electrophysiology in individual cells and paves the way for true optogenetic control in behaving animals.
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Affiliation(s)
- Amelie C F Bergs
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Silvia Rodriguez-Rozada
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Qiang Liu
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA
- Department of Neuroscience, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Christin Wirt
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Artur Bessel
- Independent Researcher, Melatener Strasse 93, 52074, Aachen, Germany
| | - Nadja Zeitzschel
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Hilal Durmaz
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Adrianna Nozownik
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Holger Dill
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Maëlle Jospin
- Université Claude Bernard Lyon 1, Institut NeuroMyoGène, 8 Avenue Rockefeller, 69008, Lyon, France
| | - Johannes Vierock
- Institute for Biology, Experimental Biophysics, Humboldt University, 10115, Berlin, Germany
| | - Cornelia I Bargmann
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA
- Chan Zuckerberg Initiative, Palo Alto, CA, USA
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt University, 10115, Berlin, Germany
| | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
- Medical Faculty Mannheim, University of Heidelberg, Ludolf-Krehl-Strasse 13-17, 68167, Mannheim, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.
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12
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Functional Insights into Protein Kinase A (PKA) Signaling from C. elegans. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111878. [PMID: 36431013 PMCID: PMC9692727 DOI: 10.3390/life12111878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/04/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
Protein kinase A (PKA), which regulates a diverse set of biological functions downstream of cyclic AMP (cAMP), is a tetramer consisting of two catalytic subunits (PKA-C) and two regulatory subunits (PKA-R). When cAMP binds the PKA-R subunits, the PKA-C subunits are released and interact with downstream effectors. In Caenorhabditis elegans (C. elegans), PKA-C and PKA-R are encoded by kin-1 and kin-2, respectively. This review focuses on the contributions of work in C. elegans to our understanding of the many roles of PKA, including contractility and oocyte maturation in the reproductive system, lipid metabolism, physiology, mitochondrial function and lifespan, and a wide variety of behaviors. C. elegans provides a powerful genetic platform for understanding how this kinase can regulate an astounding variety of physiological responses.
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13
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Characterization of adjacent charged residues near the agonist binding site of the nematode UNC-49 GABA receptor. Mol Biochem Parasitol 2022; 252:111521. [PMID: 36100173 DOI: 10.1016/j.molbiopara.2022.111521] [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: 04/30/2022] [Revised: 08/18/2022] [Accepted: 09/08/2022] [Indexed: 12/31/2022]
Abstract
The UNC-49 receptor is a Cys-loop GABA receptor that is unique to the nematode phylum. The receptor differs from mammalian GABA receptors both in amino acid sequence and pharmacology which highlights its potential as a novel anthelmintic target. Sequence differences within and near the various ligand-binding loops of the nematode receptor suggest that there could be structural differences compared to mammalian receptors that result in different pharmacological and functional features. Here we investigated three residues in the UNC-49 receptor from the parasitic nematode Haemonchus contortus: K181, E183, and T230. Analysis of these residues was conducted via site-directed mutagenesis, electrophysiology, MD simulations, and mutant cycling analysis. In the UNC-49 receptor, E183 lies in close proximity to K181 where together they appear to play a role in GABA sensitivity and pharmacology, possibly interacting via an ionic bond. While the introduction of single alanine residues at each position separately had a negative impact on GABA EC50, the double alanine mutant (K181A/E183A) exhibited wildtype-level GABA EC50 and some differences in pharmacology. Overall, this study has revealed a potentially novel role for these two residues in nematode UNC-49 GABA receptors that could aid in understanding their function.
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14
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Rashid A, Tevlin M, Lu Y, Shaham S. A developmental pathway for epithelial-to-motoneuron transformation in C. elegans. Cell Rep 2022; 40:111414. [PMID: 36170838 PMCID: PMC9579992 DOI: 10.1016/j.celrep.2022.111414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/18/2022] [Accepted: 09/01/2022] [Indexed: 11/24/2022] Open
Abstract
Motoneurons and motoneuron-like pancreatic β cells arise from radial glia and ductal cells, respectively, both tube-lining progenitors that share molecular regulators. To uncover programs underlying motoneuron formation, we studied a similar, cell-division-independent transformation of the C. elegans tube-lining Y cell into the PDA motoneuron. We find that lin-12/Notch acts through ngn-1/Ngn and its regulator hlh-16/Olig to control transformation timing. lin-12 loss blocks transformation, while lin-12(gf) promotes precocious PDA formation. Early basal expression of ngn-1/Ngn and hlh-16/Olig depends on sem-4/Sall and egl-5/Hox. Later, coincident with Y cell morphological changes, ngn-1/Ngn expression is upregulated in a sem-4/Sall and egl-5/Hox-dependent but hlh-16/Olig-independent manner. Subsequently, Y cell retrograde extension forms an anchored process priming PDA axon extension. Extension requires ngn-1-dependent expression of the cytoskeleton organizers UNC-119, UNC-44/ANK, and UNC-33/CRMP, which also activate PDA terminal-gene expression. Our findings uncover cell-division-independent regulatory events leading to motoneuron generation, suggesting a conserved pathway for epithelial-to-motoneuron/motoneuron-like cell differentiation. Rashid et al. report on a conserved epithelial-to-motoneuron transformation pathway in C. elegans requiring ngn-1/Ngn and hlh-16/Olig. lin-12/Notch regulates transformation timing through these genes, while ngn-1/Ngn and hlh-16/Olig expression levels are regulated by sem-4/Sall and egl-5/Hox. Unexpectedly, the cytoskeleton organizers UNC-119, UNC-44, and UNC-33, which are ngn-1/Ngn targets, promote motoneuron terminal identity.
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Affiliation(s)
- Alina Rashid
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Maya Tevlin
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yun Lu
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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15
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JM-20 affects GABA neurotransmission in Caenorhabditis elegans. Neurotoxicology 2022; 93:37-44. [PMID: 36029931 DOI: 10.1016/j.neuro.2022.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 08/19/2022] [Accepted: 08/20/2022] [Indexed: 11/22/2022]
Abstract
Along with the discovery of new candidate molecules for pharmaceuticals, several studies have emerged showing different mechanisms of action and toxicological aspects. 3-ethoxycarbonyl-2-methyl-4- (2-nitrophenyl)4,11-dihydro-1H-pyrido [2,3-b] [1,5] benzodiazepine (JM-20) is a hybrid molecule. It is derived from 1,5-benzodiazepines and structurally differentiated by the addition of 1,4-dihydropyridine bonded to the benzodiazepine ring. This gives this molecule potential neuroprotective, antioxidant, and anxiolytic activity. As this is a promising multi-target molecule, further studies are necessary to improve the knowledge about its mechanism of action. In our study, we used Caenorhabditis elegans (C. elegans) to investigate the effects of chronic treatment with JM-20. Nematodes from the wild-type strain (N2) were treated chronically at different concentrations of JM-20. Our results show that JM-20 does not cause mortality, but higher concentrations can delay the development of worms after 48h exposure. We assessed basic behaviors in the worm, and our data demonstrate decreased defecation cycle. Our results suggest that JM-20 acts on the C. elegans GABAergic system because GABA neurotransmission is associated with the worm intestine. We also observed increased locomotor activity and decreased egg-laying after JM-20 treatment. When both behaviors were evaluated in mutants with have reduced levels of GABA (unc-25), this effect is no observed, suggesting the GABAergic modulation. Still, the JM-20 exert similar effect of Diazepam in basic behaviors observed. To reinforce neuromodulatory action, computational analysis was performed, and results showed a JM-20 binding on allosteric sites of nematodes GABA receptors. Overall, this work provided a better understanding of the effects of JM-20 in C. elegans as well as showed the effects of this new molecule on the GABAergic system in this animal model.
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16
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Kaulich E, Carroll T, Ackley BD, Tang YQ, Hardege I, Nehrke K, Schafer WR, Walker DS. Distinct roles for two Caenorhabditis elegans acid-sensing ion channels in an ultradian clock. eLife 2022; 11:e75837. [PMID: 35666106 PMCID: PMC9374441 DOI: 10.7554/elife.75837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Biological clocks are fundamental to an organism's health, controlling periodicity of behaviour and metabolism. Here, we identify two acid-sensing ion channels, with very different proton sensing properties, and describe their role in an ultradian clock, the defecation motor program (DMP) of the nematode Caenorhabditis elegans. An ACD-5-containing channel, on the apical membrane of the intestinal epithelium, is essential for maintenance of luminal acidity, and thus the rhythmic oscillations in lumen pH. In contrast, the second channel, composed of FLR-1, ACD-3 and/or DEL-5, located on the basolateral membrane, controls the intracellular Ca2+ wave and forms a core component of the master oscillator that controls the timing and rhythmicity of the DMP. flr-1 and acd-3/del-5 mutants show severe developmental and metabolic defects. We thus directly link the proton-sensing properties of these channels to their physiological roles in pH regulation and Ca2+ signalling, the generation of an ultradian oscillator, and its metabolic consequences.
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Affiliation(s)
- Eva Kaulich
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Trae Carroll
- Department of Pathology and Lab Medicine, University of Rochester Medical CenterRochesterUnited States
| | - Brian D Ackley
- Department of Molecular Biosciences, University of KansasLawrenceUnited States
| | - Yi-Quan Tang
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Iris Hardege
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Keith Nehrke
- Department of Medicine, Nephrology Division, University of Rochester Medical CenterRochesterUnited States
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of Biology, KU LeuvenLeuvenBelgium
| | - Denise S Walker
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
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17
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Jiang J, Su Y, Zhang R, Li H, Tao L, Liu Q. C. elegans enteric motor neurons fire synchronized action potentials underlying the defecation motor program. Nat Commun 2022; 13:2783. [PMID: 35589790 PMCID: PMC9120479 DOI: 10.1038/s41467-022-30452-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
C. elegans neurons were thought to be non-spiking until our recent discovery of action potentials in the sensory neuron AWA; however, the extent to which the C. elegans nervous system relies on analog or digital coding is unclear. Here we show that the enteric motor neurons AVL and DVB fire synchronous all-or-none calcium-mediated action potentials following the intestinal pacemaker during the rhythmic C. elegans defecation behavior. AVL fires unusual compound action potentials with each depolarizing calcium spike mediated by UNC-2 followed by a hyperpolarizing potassium spike mediated by a repolarization-activated potassium channel EXP-2. Simultaneous behavior tracking and imaging in free-moving animals suggest that action potentials initiated in AVL propagate along its axon to activate precisely timed DVB action potentials through the INX-1 gap junction. This work identifies a novel circuit of spiking neurons in C. elegans that uses digital coding for long-distance communication and temporal synchronization underlying reliable behavioral rhythm.
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Affiliation(s)
- Jingyuan Jiang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yifan Su
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Ruilin Zhang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
- Yuanpei College, Peking University, Beijing, 100871, China
| | - Haiwen Li
- LMAM, School of Mathematical Sciences, Peking University, Beijing, 100871, China
| | - Louis Tao
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Qiang Liu
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA.
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR.
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18
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Choudhary S, Kashyap SS, Martin RJ, Robertson AP. Advances in our understanding of nematode ion channels as potential anthelmintic targets. Int J Parasitol Drugs Drug Resist 2022; 18:52-86. [PMID: 35149380 PMCID: PMC8841521 DOI: 10.1016/j.ijpddr.2021.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/15/2022]
Abstract
Ion channels are specialized multimeric proteins that underlie cell excitability. These channels integrate with a variety of neuromuscular and biological functions. In nematodes, the physiological behaviors including locomotion, navigation, feeding and reproduction, are regulated by these protein entities. Majority of the antinematodal chemotherapeutics target the ion channels to disrupt essential biological functions. Here, we have summarized current advances in our understanding of nematode ion channel pharmacology. We review cys-loop ligand gated ion channels (LGICs), including nicotinic acetylcholine receptors (nAChRs), acetylcholine-chloride gated ion channels (ACCs), glutamate-gated chloride channels (GluCls), and GABA (γ-aminobutyric acid) receptors, and other ionotropic receptors (transient receptor potential (TRP) channels and potassium ion channels). We have provided an update on the pharmacological properties of these channels from various nematodes. This article catalogs the differences in ion channel composition and resulting pharmacology in the phylum Nematoda. This diversity in ion channel subunit repertoire and pharmacology emphasizes the importance of pursuing species-specific drug target research. In this review, we have provided an overview of recent advances in techniques and functional assays available for screening ion channel properties and their application.
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Affiliation(s)
- Shivani Choudhary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Sudhanva S Kashyap
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
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19
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Chou SH, Chen YJ, Liao CP, Pan CL. A role for dopamine in C. elegans avoidance behavior induced by mitochondrial stress. Neurosci Res 2022; 178:87-92. [PMID: 35074444 DOI: 10.1016/j.neures.2022.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/21/2021] [Accepted: 01/17/2022] [Indexed: 01/11/2023]
Abstract
Physiological stress triggers aversive learning that profoundly alters animal behavior. Systemic mitochondrial disruption induces avoidance of C. elegans to non-pathogenic food bacteria. Mutations in cat-2 and dat-1, which control dopamine synthesis and reuptake, respectively, impair this learned bacterial avoidance, suggesting that dopaminergic modulation is essential. Cell-specific rescue experiments indicate that dopamine likely acts from the CEP and ADE neurons to regulate learned bacterial avoidance. We find that mutations in multiple dopamine receptor genes, including dop-1, dop-2 and dop-3, reduced learned bacterial avoidance. Our work reveals a role for dopamine signaling in C. elegans learned avoidance behavior induced by mitochondrial stress.
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Affiliation(s)
- Shih-Hua Chou
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yen-Ju Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chien-Po Liao
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan.
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20
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Huang QT, Sheng CW, Jones AK, Jiang J, Tang T, Han ZJ, Zhao CQ. Functional Characteristics of the Lepidopteran Ionotropic GABA Receptor 8916 Subunit Interacting with the LCCH3 or the RDL Subunit. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11582-11591. [PMID: 34555899 DOI: 10.1021/acs.jafc.1c00385] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The ionotropic γ-aminobutyric acid (iGABA) receptor is commonly considered as a fast inhibitory channel and is an important insecticide target. Since 1990, RDL, LCCH3, and GRD have been successively isolated and found to be potential subunits of the insect iGABA receptor. More recently, one orphan gene named 8916 was found and considered to be another potential iGABA receptor subunit according to its amino acid sequence. However, little information about 8916 has been reported. Here, the 8916 subunit from Chilo suppressalis was studied to determine whether it can form part of a functional iGABA receptor by co-expressing this subunit with CsRDL1 or CsLCCH3 in the Xenopus oocyte system. Cs8916 or CsLCCH3 did not form functional ion channels when expressed alone. However, Cs8916 was able to form heteromeric ion channels when expressed with either CsLCCH3 or CsRDL1. The recombinant heteromeric Cs8916/LCCH3 channel was a cation-selective channel, which was sensitive to GABA or β-alanine. The current of the Cs8916/LCCH3 channel was inhibited by dieldrin, endosulfan, fipronil, or ethiprole. In contrast, fluralaner, broflanilide, and avermectin showed little effect on the Cs8916/LCCH3 channel (IC50s > 10 000 nM). The Cs8916/RDL1 channel was sensitive to GABA, but was significantly different in EC50 and Imax for GABA to those of homomeric CsRDL1. Fluralaner, fipronil, or dieldrin showed antagonistic actions on Cs8916/RDL1. In conclusion, Cs8916 is a potential iGABA receptor subunit, which can interact with CsLCCH3 to generate a cation-selective channel that is sensitive to several insecticides. Also, as Cs8916/RDL1 has a higher EC50 than homomeric CsRDL1, Cs8916 may affect the physiological functions of CsRDL1 and therefore play a role in fine-tuning GABAergic signaling.
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Affiliation(s)
- Qiu Tang Huang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Cheng Wang Sheng
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, U.K
| | - Jie Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha 410125, P. R. China
| | - Zhao Jun Han
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Chun Qing Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China
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21
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Nomura K, Yoshizumi S, Ozoe F, Ozoe Y. Molecular cloning and pharmacology of Min-UNC-49B, a GABA receptor from the southern root-knot nematode Meloidogyne incognita. PEST MANAGEMENT SCIENCE 2021; 77:3763-3776. [PMID: 32954620 DOI: 10.1002/ps.6096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/11/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Root-knot nematodes are plant-parasitic nematodes that cause immense damage to a broad range of cultivated crops by forming root galls, resulting in yield losses in crops. To facilitate the development of faster-acting selective nematicides, we cloned three cDNAs encoding UNC-49B proteins from the southern root-knot nematode Meloidogyne incognita and examined their functional and pharmacological properties by two-electrode voltage clamp electrophysiology using a Xenopus oocyte expression system. RESULTS The three cloned cDNAs encoded Min-UNC-49B, Min-UNC-49B-L and Min-UNC-49B-XL; the last two proteins have longer N-terminal regions than the first protein. When expressed in Xenopus oocytes, these proteins responded to γ-aminobutyric acid (GABA) to activate currents with high-micromolar or low-millimolar half-maximal effective concentration (EC50 ) values, indicating the formation of functional homo-pentameric GABA receptors. Fipronil and picrotoxinin inhibited GABA-induced currents with high-nanomolar and low-micromolar half-maximal inhibitory concentration (IC50 ) values, respectively, in oocytes expressing Min-UNC-49B. The G2'A and T6'M mutations in the second transmembrane domain of Min-UNC-49B enhanced and reduced the sensitivity of Min-UNC-49B to these two antagonists, respectively. Samaderine B and SF-14 inhibited GABA responses in oocytes expressing Min-UNC-49B with low-micromolar and high-nanomolar IC50 values, respectively. Ivermectin, α-terpineol, thymol and methyl eugenol exerted dual effects on Min-UNC-49B by potentiating currents induced by low concentrations of GABA and inhibiting currents induced by high concentrations of GABA. CONCLUSION We have shown that structurally diverse compounds act at Min-UNC-49B GABA receptors. Our results may serve as a starting point to decipher the molecular function of native GABA receptors of plant-parasitic nematodes, which could aid in the structure-based design of novel nematicides. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Kazuki Nomura
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan
| | - Satoru Yoshizumi
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan
| | - Fumiyo Ozoe
- Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane, Japan
| | - Yoshihisa Ozoe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan
- Interdisciplinary Institute for Science Research, Organization for Research and Academic Information, Shimane University, Matsue, Shimane, Japan
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22
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Thomas JT, Spady BL, Munday PL, Watson SA. The role of ligand-gated chloride channels in behavioural alterations at elevated CO2 in a cephalopod. J Exp Biol 2021; 224:269059. [PMID: 34100547 DOI: 10.1242/jeb.242335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/30/2021] [Indexed: 11/20/2022]
Abstract
Projected future carbon dioxide (CO2) levels in the ocean can alter marine animal behaviours. Disrupted functioning of γ-aminobutyric acid type A (GABAA) receptors (ligand-gated chloride channels) is suggested to underlie CO2-induced behavioural changes in fish. However, the mechanisms underlying behavioural changes in marine invertebrates are poorly understood. We pharmacologically tested the role of GABA-, glutamate-, acetylcholine- and dopamine-gated chloride channels in CO2-induced behavioural changes in a cephalopod, the two-toned pygmy squid (Idiosepius pygmaeus). We exposed squid to ambient (∼450 µatm) or elevated (∼1000 µatm) CO2 for 7 days. Squid were treated with sham, the GABAA receptor antagonist gabazine or the non-specific GABAA receptor antagonist picrotoxin, before measurement of conspecific-directed behaviours and activity levels upon mirror exposure. Elevated CO2 increased conspecific-directed attraction and aggression, as well as activity levels. For some CO2-affected behaviours, both gabazine and picrotoxin had a different effect at elevated compared with ambient CO2, providing robust support for the GABA hypothesis within cephalopods. In another behavioural trait, picrotoxin but not gabazine had a different effect in elevated compared with ambient CO2, providing the first pharmacological evidence, in fish and marine invertebrates, for altered functioning of ligand-gated chloride channels, other than the GABAAR, underlying CO2-induced behavioural changes. For some other behaviours, both gabazine and picrotoxin had a similar effect in elevated and ambient CO2, suggesting altered function of ligand-gated chloride channels was not responsible for these CO2-induced changes. Multiple mechanisms may be involved, which could explain the variability in the CO2 and drug treatment effects across behaviours.
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Affiliation(s)
- Jodi T Thomas
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Blake L Spady
- Coral Reef Watch, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA.,ReefSense Pty Ltd., Cranbrook, QLD 4814, Australia
| | - Philip L Munday
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Sue-Ann Watson
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.,Biodiversity and Geosciences Program, Museum of Tropical Queensland, Queensland Museum Network, Townsville, QLD 4810, Australia
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23
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Choi U, Wang H, Hu M, Kim S, Sieburth D. Presynaptic coupling by electrical synapses coordinates a rhythmic behavior by synchronizing the activities of a neuron pair. Proc Natl Acad Sci U S A 2021; 118:e2022599118. [PMID: 33972428 PMCID: PMC8157971 DOI: 10.1073/pnas.2022599118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electrical synapses are specialized structures that mediate the flow of electrical currents between neurons and have well known roles in synchronizing the activities of neuronal populations, both by mediating the current transfer from more active to less active neurons and by shunting currents from active neurons to their less active neighbors. However, how these positive and negative functions of electrical synapses are coordinated to shape rhythmic synaptic outputs and behavior is not well understood. Here, using a combination of genetics, behavioral analysis, and live calcium imaging in Caenorhabditis elegans, we show that electrical synapses formed by the gap junction protein INX-1/innexin couple the presynaptic terminals of a pair of motor neurons (AVL and DVB) to synchronize their activation in response to a pacemaker signal. Live calcium imaging reveals that inx-1/innexin mutations lead to asynchronous activation of AVL and DVB, due, in part, to loss of AVL-mediated activation of DVB by the pacemaker. In addition, loss of inx-1 leads to the ectopic activation of DVB at inappropriate times during the cycle through the activation of the L-type voltage-gated calcium channel EGL-19. We propose that electrical synapses between AVL and DVB presynaptic terminals function to ensure the precise and robust execution of a specific step in a rhythmic behavior by both synchronizing the activities of presynaptic terminals in response to pacemaker signaling and by inhibiting their activation in between cycles when pacemaker signaling is low.
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Affiliation(s)
- Ukjin Choi
- Development, Stem Cell, and Regenerative Medicine Graduate Program, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033
| | - Han Wang
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033
| | - Mingxi Hu
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033
| | - Sungjin Kim
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033;
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
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24
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Dauer Formation in C. elegans Is Modulated through AWC and ASI-Dependent Chemosensation. eNeuro 2021; 8:ENEURO.0473-20.2021. [PMID: 33712439 PMCID: PMC8174048 DOI: 10.1523/eneuro.0473-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/25/2021] [Accepted: 03/06/2021] [Indexed: 12/30/2022] Open
Abstract
The perception of our surrounding environment is an amalgamation of stimuli detected by sensory neurons. In Caenorhabditis elegans, olfaction is an essential behavior that determines various behavioral functions such as locomotion, feeding and development. Sensory olfactory cues also initiate downstream neuroendocrine signaling that controls aging, learning, development and reproduction. Innate sensory preferences toward odors (food, pathogens) and reproductive pheromones are modulated by 11 pairs of amphid chemosensory neurons in the head region of C. elegans. Amongst these sensory neurons, the ASI neuron has neuroendocrine functions and secretes neuropeptides, insulin-like peptide (DAF-28) and the TGF-β protein, DAF-7. Its expression levels are modulated by the presence of food (increased levels) and population density (decreased levels). A recent study has shown that EXP-1, an excitatory GABA receptor regulates DAF-7/TGF-β levels and participates in DAF-7/TGF-β-mediated behaviors such as aggregation and bordering. Here, we show that exp-1 mutants show defective responses toward AWC-sensed attractive odors in a non-autonomous manner through ASI neurons. Our dauer experiments reveal that in daf-7 mutants, ASI expressed EXP-1 and STR-2 (a G-protein-coupled receptor; GPCR) that partially maintained reproductive growth of animals. Further, studies suggest that neuronal connections between ASI and AWC neurons are allowed at least partially through ASI secreted DAF-7 or through alternate TGF- β pathway/s regulated by EXP-1 and STR-2. Together, our behavioral, genetic and imaging experiments propose that EXP-1 and STR-2 integrate food cues and allow the animals to display DAF-7/TGF-β neuroendocrine dependent or independent behavioral responses contributing to chemosensensory and developmental plasticity.
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25
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Yemini E, Lin A, Nejatbakhsh A, Varol E, Sun R, Mena GE, Samuel ADT, Paninski L, Venkatachalam V, Hobert O. NeuroPAL: A Multicolor Atlas for Whole-Brain Neuronal Identification in C. elegans. Cell 2021; 184:272-288.e11. [PMID: 33378642 PMCID: PMC10494711 DOI: 10.1016/j.cell.2020.12.012] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 06/30/2020] [Accepted: 12/08/2020] [Indexed: 12/31/2022]
Abstract
Comprehensively resolving neuronal identities in whole-brain images is a major challenge. We achieve this in C. elegans by engineering a multicolor transgene called NeuroPAL (a neuronal polychromatic atlas of landmarks). NeuroPAL worms share a stereotypical multicolor fluorescence map for the entire hermaphrodite nervous system that resolves all neuronal identities. Neurons labeled with NeuroPAL do not exhibit fluorescence in the green, cyan, or yellow emission channels, allowing the transgene to be used with numerous reporters of gene expression or neuronal dynamics. We showcase three applications that leverage NeuroPAL for nervous-system-wide neuronal identification. First, we determine the brainwide expression patterns of all metabotropic receptors for acetylcholine, GABA, and glutamate, completing a map of this communication network. Second, we uncover changes in cell fate caused by transcription factor mutations. Third, we record brainwide activity in response to attractive and repulsive chemosensory cues, characterizing multimodal coding for these stimuli.
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Affiliation(s)
- Eviatar Yemini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA.
| | - Albert Lin
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Amin Nejatbakhsh
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Erdem Varol
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Ruoxi Sun
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Gonzalo E Mena
- Department of Statistics and Data Science Initiative, Harvard University, Cambridge, MA 02138, USA
| | - Aravinthan D T Samuel
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Liam Paninski
- Departments of Statistics and Neuroscience, Grossman Center for the Statistics of Mind, Center for Theoretical Neuroscience, Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | | | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
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26
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Fenyves BG, Szilágyi GS, Vassy Z, Sőti C, Csermely P. Synaptic polarity and sign-balance prediction using gene expression data in the Caenorhabditis elegans chemical synapse neuronal connectome network. PLoS Comput Biol 2020; 16:e1007974. [PMID: 33347479 PMCID: PMC7785220 DOI: 10.1371/journal.pcbi.1007974] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 01/05/2021] [Accepted: 10/19/2020] [Indexed: 12/16/2022] Open
Abstract
Graph theoretical analyses of nervous systems usually omit the aspect of connection polarity, due to data insufficiency. The chemical synapse network of Caenorhabditis elegans is a well-reconstructed directed network, but the signs of its connections are yet to be elucidated. Here, we present the gene expression-based sign prediction of the ionotropic chemical synapse connectome of C. elegans (3,638 connections and 20,589 synapses total), incorporating available presynaptic neurotransmitter and postsynaptic receptor gene expression data for three major neurotransmitter systems. We made predictions for more than two-thirds of these chemical synapses and observed an excitatory-inhibitory (E:I) ratio close to 4:1 which was found similar to that observed in many real-world networks. Our open source tool (http://EleganSign.linkgroup.hu) is simple but efficient in predicting polarities by integrating neuronal connectome and gene expression data.
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Affiliation(s)
- Bánk G. Fenyves
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
- Department of Emergency Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor S. Szilágyi
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
| | - Zsolt Vassy
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
| | - Csaba Sőti
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
| | - Peter Csermely
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
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27
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GABAergic motor neurons bias locomotor decision-making in C. elegans. Nat Commun 2020; 11:5076. [PMID: 33033264 PMCID: PMC7544903 DOI: 10.1038/s41467-020-18893-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 09/17/2020] [Indexed: 12/18/2022] Open
Abstract
Proper threat-reward decision-making is critical to animal survival. Emerging evidence indicates that the motor system may participate in decision-making but the neural circuit and molecular bases for these functions are little known. We found in C. elegans that GABAergic motor neurons (D-MNs) bias toward the reward behavior in threat-reward decision-making by retrogradely inhibiting a pair of premotor command interneurons, AVA, that control cholinergic motor neurons in the avoidance neural circuit. This function of D-MNs is mediated by a specific ionotropic GABA receptor (UNC-49) in AVA, and depends on electrical coupling between the two AVA interneurons. Our results suggest that AVA are hub neurons where sensory inputs from threat and reward sensory modalities and motor information from D-MNs are integrated. This study demonstrates at single-neuron resolution how motor neurons may help shape threat-reward choice behaviors through interacting with other neurons.
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28
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Buckingham SD, Mann HJ, Hearnden OK, Sattelle DB. Turning a Drug Target into a Drug Candidate: A New Paradigm for Neurological Drug Discovery? Bioessays 2020; 42:e2000011. [PMID: 32776366 DOI: 10.1002/bies.202000011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/26/2020] [Indexed: 11/11/2022]
Abstract
The conventional paradigm for developing new treatments for disease mainly involves either the discovery of new drug targets, or finding new, improved drugs for old targets. However, an ion channel found only in invertebrates offers the potential of a completely new paradigm in which an established drug target can be re-engineered to serve as a new candidate therapeutic agent. The L-glutamate-gated chloride channels (GluCls) of invertebrates are absent from vertebrate genomes, offering the opportunity to introduce this exogenous, inhibitory, L-glutamate receptor into vertebrate neuronal circuits either as a tool with which to study neural networks, or a candidate therapy. Epileptic seizures can involve L-glutamate-induced hyper-excitation and toxicity. Variant GluCls, with their inhibitory responses to L-glutamate, when engineered into human neurons, might counter the excitotoxic effects of excess L-glutamate. In reviewing recent studies on model organisms, it appears that this approach might offer a new paradigm for the development of candidate therapeutics for epilepsy.
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Affiliation(s)
- Steven D Buckingham
- School of Biological and Chemical Sciences, Queen Mary University London, Mile End Road, London, E1 4NS, UK.,UCL Respiratory, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Harry-Jack Mann
- UCL Respiratory, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Olivia K Hearnden
- UCL Respiratory, University College London, 5 University Street, London, WC1E 6JF, UK
| | - David B Sattelle
- UCL Respiratory, University College London, 5 University Street, London, WC1E 6JF, UK
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29
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Henry C, Cens T, Charnet P, Cohen-Solal C, Collet C, van-Dijk J, Guiramand J, de Jésus-Ferreira MC, Menard C, Mokrane N, Roussel J, Thibault JB, Vignes M, Rousset M. Heterogeneous expression of GABA receptor-like subunits LCCH3 and GRD reveals functional diversity of GABA receptors in the honeybee Apis mellifera. Br J Pharmacol 2020; 177:3924-3940. [PMID: 32436264 DOI: 10.1111/bph.15135] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 04/24/2020] [Accepted: 05/09/2020] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE Despite a growing awareness, annual losses of honeybee colonies worldwide continue to reach threatening levels for food safety and global biodiversity. Among the biotic and abiotic stresses probably responsible for these losses, pesticides, including those targeting ionotropic GABA receptors, are one of the major drivers. Most insect genomes include the ionotropic GABA receptor subunit gene, Rdl, and two GABA-like receptor subunit genes, Lcch3 and Grd. Most studies have focused on Rdl which forms homomeric GABA-gated chloride channels, and a complete analysis of all possible molecular combinations of GABA receptors is still lacking. EXPERIMENTAL APPROACH We cloned the Rdl, Grd, and Lcch3 genes of Apis mellifera and systematically characterized the resulting GABA receptors expressed in Xenopus oocytes, using electrophysiological assays, fluorescence microscopy and co-immunoprecipitation techniques. KEY RESULTS The cloned subunits interacted with each other, forming GABA-gated heteromeric channels with particular properties. Strikingly, these heteromers were always more sensitive than AmRDL homomer to all the pharmacological agents tested. In particular, when expressed together, Grd and Lcch3 form a non-selective cationic channel that opens at low concentrations of GABA and with sensitivity to insecticides similar to that of homomeric Rdl channels. CONCLUSION AND IMPLICATIONS For off-target species like the honeybee, chronic sublethal exposure to insecticides constitutes a major threat. At these concentration ranges, homomeric RDL receptors may not be the most pertinent target to study and other ionotropic GABA receptor subtypes should be considered in order to understand more fully the molecular mechanisms of sublethal toxicity to insecticides.
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Affiliation(s)
| | - Thierry Cens
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Pierre Charnet
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | | | - Claude Collet
- UR 406 Abeilles et Environnement, INRAE, Avignon Cedex 9, France
| | | | | | | | - Claudine Menard
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Nawfel Mokrane
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Julien Roussel
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | | | - Michel Vignes
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
| | - Matthieu Rousset
- IBMM UMR5247, University of Montpellier, CNRS, Montpellier, France
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30
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Zhang QQ, Qiao M. Transcriptional response of springtail (Folsomia candida) exposed to decabromodiphenyl ether-contaminated soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 719:134859. [PMID: 31837853 DOI: 10.1016/j.scitotenv.2019.134859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/29/2019] [Accepted: 10/05/2019] [Indexed: 05/22/2023]
Abstract
Decabromodiphenyl ether (BDE209) is a widely used brominated flame retardant that has become a common soil contaminant of concern due to its persistence and toxicity. However, little is known about molecular-level effects of BDE209 on soil invertebrates. Here, we detected changes in gene transcription of the soil springtail, Folsomia candida, exposed to BDE209 (0.81 mg/kg) in soil for 2, 7 and 14 days. We identified 16 and 771 significantly differentially expressed genes after 2 and 7 days of exposure respectively, and no significantly regulated genes were shared among the two time points. No genes were affected after 14 days of exposure. According to the annotation of the significantly differently expressed genes at 2 and 7 day exposure, we found that BDE209 affected the transcription of genes involved in moulting, neural signal transmission and detoxification. Our results suggested that BDE209 could disrupt moulting of F. candida via the ecdysteroid pathway, and cause neurotoxicity through disrupting some neurotransmitter signalling pathways. This study provided insights into the toxic mechanism of BDE209 on F. candida.
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Affiliation(s)
- Qian-Qian Zhang
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Qiao
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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31
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Zhou X, Bessereau JL. Molecular Architecture of Genetically-Tractable GABA Synapses in C. elegans. Front Mol Neurosci 2019; 12:304. [PMID: 31920535 PMCID: PMC6920096 DOI: 10.3389/fnmol.2019.00304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/26/2019] [Indexed: 12/18/2022] Open
Abstract
Inhibitory synapses represent a minority of the total chemical synapses in the mammalian brain, yet proper tuning of inhibition is fundamental to shape neuronal network properties. The neurotransmitter γ-aminobutyric acid (GABA) mediates rapid synaptic inhibition by the activation of the type A GABA receptor (GABAAR), a pentameric chloride channel that governs major inhibitory neuronal transduction in the nervous system. Impaired GABA transmission leads to a variety of neuropsychiatric diseases, including schizophrenia, autism, epilepsy or anxiety. From an evolutionary perspective, GABAAR shows remarkable conservations, and are found in all eukaryotic clades and even in bacteria and archaea. Specifically, bona fide GABAARs are found in the nematode Caenorhabditis elegans. Because of the anatomical simplicity of the nervous system and its amenability to genetic manipulations, C. elegans provide a powerful system to investigate the molecular and cellular biology of GABA synapses. In this mini review article, we will introduce the structure of the C. elegans GABAergic system and describe recent advances that have identified novel proteins controlling the localization of GABAARs at synapses. In particular, Ce-Punctin/MADD-4 is an evolutionarily-conserved extracellular matrix protein that behaves as an anterograde synaptic organizer to instruct the excitatory or inhibitory identity of postsynaptic domains.
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Affiliation(s)
- Xin Zhou
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène, Lyon, France
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32
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Steuer Costa W, Van der Auwera P, Glock C, Liewald JF, Bach M, Schüler C, Wabnig S, Oranth A, Masurat F, Bringmann H, Schoofs L, Stelzer EHK, Fischer SC, Gottschalk A. A GABAergic and peptidergic sleep neuron as a locomotion stop neuron with compartmentalized Ca2+ dynamics. Nat Commun 2019; 10:4095. [PMID: 31506439 PMCID: PMC6736843 DOI: 10.1038/s41467-019-12098-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022] Open
Abstract
Animals must slow or halt locomotion to integrate sensory inputs or to change direction. In Caenorhabditis elegans, the GABAergic and peptidergic neuron RIS mediates developmentally timed quiescence. Here, we show RIS functions additionally as a locomotion stop neuron. RIS optogenetic stimulation caused acute and persistent inhibition of locomotion and pharyngeal pumping, phenotypes requiring FLP-11 neuropeptides and GABA. RIS photoactivation allows the animal to maintain its body posture by sustaining muscle tone, yet inactivating motor neuron oscillatory activity. During locomotion, RIS axonal Ca2+ signals revealed functional compartmentalization: Activity in the nerve ring process correlated with locomotion stop, while activity in a branch correlated with induced reversals. GABA was required to induce, and FLP-11 neuropeptides were required to sustain locomotion stop. RIS attenuates neuronal activity and inhibits movement, possibly enabling sensory integration and decision making, and exemplifies dual use of one cell across development in a compact nervous system.
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Affiliation(s)
- Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Petrus Van der Auwera
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Caspar Glock
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,Max-Planck-Institute for Brain Research, Max-von-Laue-Strasse 4, 60438, Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Maximilian Bach
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Sebastian Wabnig
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.,od green GmbH, Passauerstrasse 34, 4780, Schärding am Inn, Austria
| | - Alexandra Oranth
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Florentin Masurat
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Henrik Bringmann
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Department of Biology, University of Marburg, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Liliane Schoofs
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven, Naamsestraat 59 - box 2465, 3000, Leuven, Belgium
| | - Ernst H K Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany
| | - Sabine C Fischer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.,Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Strasse 13, 60439, Frankfurt, Germany.,Center for Computational and Theoretical Biology (CCTB), University of Würzburg, Campus Hubland Nord 32, 97074, Würzburg, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany. .,Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.
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33
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Yuan F, Zhou J, Xu L, Jia W, Chun L, Xu XZS, Liu J. GABA receptors differentially regulate life span and health span in C. elegans through distinct downstream mechanisms. Am J Physiol Cell Physiol 2019; 317:C953-C963. [PMID: 31433690 DOI: 10.1152/ajpcell.00072.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GABA, a prominent inhibitory neurotransmitter, is best known to regulate neuronal functions in the nervous system. However, much less is known about the role of GABA signaling in other physiological processes. Interestingly, recent work showed that GABA signaling can regulate life span via a metabotropic GABAB receptor in Caenorhabditis elegans. However, the role of other types of GABA receptors in life span has not been clearly defined. It is also unclear whether GABA signaling regulates health span. Here, using C. elegans as a model, we systematically interrogated the role of various GABA receptors in both life span and health span. We find that mutations in four different GABA receptors extend health span by promoting resistance to stress and pathogen infection and that two such receptor mutants also show extended life span. Different GABA receptors engage distinct transcriptional factors to regulate life span and health span, and even the same receptor regulates life span and health span via different transcription factors. Our results uncover a novel, profound role of GABA signaling in aging in C. elegans, which is mediated by different GABA receptors coupled to distinct downstream effectors.
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Affiliation(s)
- Fengling Yuan
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jiejun Zhou
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lingxiu Xu
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Wenxin Jia
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Chun
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - X Z Shawn Xu
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Jianfeng Liu
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Kourakis MJ, Borba C, Zhang A, Newman-Smith E, Salas P, Manjunath B, Smith WC. Parallel visual circuitry in a basal chordate. eLife 2019; 8:44753. [PMID: 30998184 PMCID: PMC6499539 DOI: 10.7554/elife.44753] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 04/11/2019] [Indexed: 12/28/2022] Open
Abstract
A common CNS architecture is observed in all chordates, from vertebrates to basal chordates like the ascidian Ciona. Ciona stands apart among chordates in having a complete larval connectome. Starting with visuomotor circuits predicted by the Ciona connectome, we used expression maps of neurotransmitter use with behavioral assays to identify two parallel visuomotor circuits that are responsive to different components of visual stimuli. The first circuit is characterized by glutamatergic photoreceptors and responds to the direction of light. These photoreceptors project to cholinergic motor neurons, via two tiers of cholinergic interneurons. The second circuit responds to changes in ambient light and mediates an escape response. This circuit uses GABAergic photoreceptors which project to GABAergic interneurons, and then to cholinergic interneurons. Our observations on the behavior of larvae either treated with a GABA receptor antagonist or carrying a mutation that eliminates photoreceptors indicate the second circuit is disinhibitory.
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Affiliation(s)
- Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Cezar Borba
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - Angela Zhang
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, United States
| | - Erin Newman-Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - Priscilla Salas
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - B Manjunath
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - William C Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
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Abstract
The neurotransmitter gamma-aminobutyric acid (GABA) is widely distributed in the mammalian central nervous system, where it acts as a major mediator of synaptic inhibition. GABA also serves as a neurotransmitter in a range of invertebrate phyla, including arthropods, echinoderms, annelids, nematodes, and platyhelminthes. This article reviews evidence supporting the neurotransmitter role of GABA in gastropod molluscs, with an emphasis on its presence in identified neurons and well-characterized neural circuits. The collective findings indicate that GABAergic signaling participates in the selection and specification of motor programs, as well as the bilateral coordination of motor circuits. While relatively few in number, GABAergic neurons can influence neural circuits via inhibitory, excitatory, and modulatory synaptic actions. GABA's colocalization with peptidergic and classical neurotransmitters can broaden its integrative capacity. The functional properties of GABAergic neurons in simpler gastropod systems may provide insight into the role of this neurotransmitter phenotype in more complex brains.
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Key Words
- BCI, buccal-cerebral interneuron
- CBC, cerebral-buccal connective
- CBI, cerebral-buccal interneuron
- CNS, central nervous system
- CPG, central pattern generator
- Cr-Aint, cerebral A interneuron
- DA, dopamine
- EPSP, excitatory postsynaptic potential
- FCAP, feeding circuit activating peptide
- GABA, gamma-aminobutyric acid
- GABAli, GABA-like immunoreactivity
- IPSP, inhibitory postsynaptic potential
- PKC, protein kinase C
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Affiliation(s)
- MARK W. MILLER
- Institute of Neurobiology and Department of Anatomy and Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico 00901
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36
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Foster J, Cochrane E, Khatami MH, Habibi SA, de Haan H, Forrester SG. A mutational and molecular dynamics study of the cys-loop GABA receptor Hco-UNC-49 from Haemonchus contortus: Agonist recognition in the nematode GABA receptor family. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:534-539. [PMID: 30361167 PMCID: PMC6287672 DOI: 10.1016/j.ijpddr.2018.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/01/2018] [Accepted: 10/04/2018] [Indexed: 11/04/2022]
Abstract
The UNC-49 receptor is a unique nematode γ-aminobutyric acid (GABA)-gated chloride channel that may prove to be a novel target for the development of nematocides. Here we have characterized various charged amino acid residues in and near the agonist binding site of the UNC-49 receptor from the parasitic nematode Haemonchus contorts. Utilizing the Caenorhabditis elegans GluCl crystal structure as a template, a model was generated and various charged residues [D83 (loop D), E131 (loop A), H137 (pre-loop E), R159 (Loop E), E185 (Loop B) and R241 (Loop C)] were investigated based on their location and conservation. These residues may contribute to structure, function, and molecular interactions with agonists. It was found that all residues chosen were important for receptor function to varying degrees. Results of the mutational analysis and molecular simulations suggest that R159 may be interacting with D83 by an ionic interaction that may be crucial for general GABA receptor function. We have used the results from this study as well as knowledge of residues involved in GABA receptor binding to identify sequence patterns that may assist in understanding the function of lesser known GABA receptor subunits from parasitic nematodes. Key functional residues were investigated in the Hco-UNC-49 receptor. A glutamic acid in the binding pocket (loop B) is essential for agonist recognition. Interaction between residues in different binding loops are important for function.
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Affiliation(s)
- Josh Foster
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada
| | - Everett Cochrane
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada
| | - Mohammad Hassan Khatami
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada
| | - Sarah A Habibi
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada
| | - Hendrick de Haan
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada
| | - Sean G Forrester
- Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4, Canada.
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Kwaka A, Hassan Khatami M, Foster J, Cochrane E, Habibi SA, de Haan HW, Forrester SG. Molecular Characterization of Binding Loop E in the Nematode Cys-Loop GABA Receptor. Mol Pharmacol 2018; 94:1289-1297. [PMID: 30194106 DOI: 10.1124/mol.118.112821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/30/2018] [Indexed: 01/27/2023] Open
Abstract
Nematodes exhibit a vast array of cys-loop ligand-gated ion channels with unique pharmacologic characteristics. However, many of the structural components that govern the binding of various ligands are unknown. The nematode cys-loop GABA receptor uncoordinated 49 (UNC-49) is an important receptor found at neuromuscular junctions that plays an important role in the sinusoidal movement of worms. The unique pharmacologic features of this receptor suggest that there are structural differences in the agonist binding site when compared with mammalian receptors. In this study, we examined each amino acid in one of the main agonist binding loops (loop E) via the substituted cysteine accessibility method (SCAM) and analyzed the interaction of various residues by molecular dynamic simulations. We found that of the 18 loop E mutants analyzed, H142C, R147C, and S157C had significant changes in GABA EC50 and were accessible to modification by a methanethiosulfonate reagent (MTSET) resulting in a change in I GABA In addition, the residue H142, which is unique to nematode UNC-49 GABA receptors, appears to play a negative role in GABA sensitivity as its mutation to cysteine increased sensitivity to GABA and caused the UNC-49 receptor partial agonist 5-aminovaleric acid (DAVA) to behave as a full agonist. Overall, this study has revealed potential differences in the agonist binding pocket between nematode UNC-49 and mammalian GABA receptors that could be exploited in the design of novel anthelmintics.
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Affiliation(s)
- Ariel Kwaka
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | | | - Joshua Foster
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - Everett Cochrane
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - Sarah A Habibi
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - Hendrick W de Haan
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - Sean G Forrester
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
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38
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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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39
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Cao J, Packer JS, Ramani V, Cusanovich DA, Huynh C, Daza R, Qiu X, Lee C, Furlan SN, Steemers FJ, Adey A, Waterston RH, Trapnell C, Shendure J. Comprehensive single-cell transcriptional profiling of a multicellular organism. Science 2017; 357:661-667. [PMID: 28818938 DOI: 10.1126/science.aam8940] [Citation(s) in RCA: 826] [Impact Index Per Article: 118.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 05/12/2017] [Accepted: 07/19/2017] [Indexed: 12/14/2022]
Abstract
To resolve cellular heterogeneity, we developed a combinatorial indexing strategy to profile the transcriptomes of single cells or nuclei, termed sci-RNA-seq (single-cell combinatorial indexing RNA sequencing). We applied sci-RNA-seq to profile nearly 50,000 cells from the nematode Caenorhabditis elegans at the L2 larval stage, which provided >50-fold "shotgun" cellular coverage of its somatic cell composition. From these data, we defined consensus expression profiles for 27 cell types and recovered rare neuronal cell types corresponding to as few as one or two cells in the L2 worm. We integrated these profiles with whole-animal chromatin immunoprecipitation sequencing data to deconvolve the cell type-specific effects of transcription factors. The data generated by sci-RNA-seq constitute a powerful resource for nematode biology and foreshadow similar atlases for other organisms.
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Affiliation(s)
- Junyue Cao
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Jonathan S Packer
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Vijay Ramani
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | | | - Chau Huynh
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Riza Daza
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Xiaojie Qiu
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Choli Lee
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Scott N Furlan
- Ben Towne Center for Childhood Cancer Research, Seattle Children's Research Institute, Seattle, WA, USA.,Department of Pediatrics, University of Washington, Seattle, WA, USA.,Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Andrew Adey
- Department of Molecular & Medical Genetics, Oregon Health & Science University, Portland, OR, USA.,Knight Cardiovascular Institute, Portland, OR, USA
| | - Robert H Waterston
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| | - Cole Trapnell
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, USA. .,Howard Hughes Medical Institute, Seattle, WA, USA
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40
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Antagonistic effect of dopamine structural analogues on human GABAρ1 receptor. Sci Rep 2017; 7:17385. [PMID: 29234054 PMCID: PMC5727059 DOI: 10.1038/s41598-017-17530-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 11/24/2017] [Indexed: 12/12/2022] Open
Abstract
GABAergic and dopaminergic pathways are co-localized in several areas of the central nervous system and recently several reports have shown co-release of both neurotransmitters. The GABA-A receptor (β and ρ1 subunits) is modulated by dopamine (DA) and, interestingly, GABAρ1 can be modulated by several biogenic amines. Here we explored the effects of the metabolites of the dopaminergic pathway and other structural analogues of DA on GABAρ1 and the DA gated ion channel (LGC-53) from Caenorhabditis elegans expressed in Xenopus laevis oocytes. Our findings show an antagonistic effect of the metabolite 3-Methoxytyramine (3-MT, IC50 = 285 ± 30 µM) with similar potency compared to DA on induced GABA currents; however, it was inactive on LGC-53. The structural DA analogues and metabolites, 3, 4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 2-phenylethylamine (β-PEA) and 4-amino-1-butanol (4-AM-1-OH), antagonized GABAρ1 currents, whereas β-PEA acted as partial agonists on LGC-53, indicating that the putative binding sites of both receptors may share structural characteristics. These results suggest that the DA metabolites 3-MT, DOPAC and HVA modulate GABAρ1 and possibly affect the activity of the receptors that include this subunit in vivo.
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41
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Cao J, Packer JS, Ramani V, Cusanovich DA, Huynh C, Daza R, Qiu X, Lee C, Furlan SN, Steemers FJ, Adey A, Waterston RH, Trapnell C, Shendure J. Comprehensive single-cell transcriptional profiling of a multicellular organism. Science 2017. [DOI: 10.1126/science.aam8940 order by 10746--] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Junyue Cao
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Jonathan S. Packer
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Vijay Ramani
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | | | - Chau Huynh
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Riza Daza
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Xiaojie Qiu
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Choli Lee
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Scott N. Furlan
- Ben Towne Center for Childhood Cancer Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Andrew Adey
- Department of Molecular & Medical Genetics, Oregon Health & Science University, Portland, OR, USA
- Knight Cardiovascular Institute, Portland, OR, USA
| | | | - Cole Trapnell
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, Seattle, WA, USA
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42
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Paré JF, Martyniuk CJ, Levin M. Bioelectric regulation of innate immune system function in regenerating and intact Xenopus laevis. NPJ Regen Med 2017; 2:15. [PMID: 29302351 PMCID: PMC5677984 DOI: 10.1038/s41536-017-0019-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/27/2017] [Accepted: 04/02/2017] [Indexed: 02/07/2023] Open
Abstract
Two key inputs that regulate regeneration are the function of the immune system, and spatial gradients of transmembrane potential (Vmem). Endogenous bioelectric signaling in somatic tissues during regenerative patterning is beginning to be understood, but its role in the context of immune response has never been investigated. Here, we show that Vmem levels modulate innate immunity activity in Xenopus laevis embryos. We developed an assay in which X. laevis embryos are infected with a uropathogenic microorganism, in the presence or absence of reagents that modify Vmem, prior to the ontogenesis of the adaptive immune system. General depolarization of the organism's Vmem by pharmacological or molecular genetic (ion channel misexpression) methods increased resistance to infection, while hyperpolarization made the embryos more susceptible to death by infection. Hyperpolarized specimens harbored a higher load of infectious microorganisms when compared to controls. We identified two mechanisms by which Vmem mediates immune function: serotonergic signaling involving melanocytes and an increase in the number of primitive myeloid cells. Bioinformatics analysis of genes whose transcription is altered by depolarization revealed a number of immune system targets consistent with mammalian data. Remarkably, amputation of the tail bud potentiates systemic resistance to infection by increasing the number of peripheral myeloid cells, revealing an interplay of regenerative response, innate immunity, and bioelectric regulation. Our study identifies bioelectricity as a new mechanism by which innate immune response can be regulated in the context of infection or regeneration. Vmem modulation using drugs already approved for human use could be exploited to improve resistance to infections in clinical settings.
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Affiliation(s)
- Jean-François Paré
- Biology Department, and Allen Discovery Center at Tufts, Tufts University, Medford, MA USA
| | - Christopher J. Martyniuk
- Center for Environmental and Human Toxicology and Department of Physiological Sciences, University of Florida Genetics Institute, College of Veterinary Medicine, University of Florida, Gainesville, FL USA
| | - Michael Levin
- Biology Department, and Allen Discovery Center at Tufts, Tufts University, Medford, MA USA
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43
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Shimizu K, Stopfer M. A Population of Projection Neurons that Inhibits the Lateral Horn but Excites the Antennal Lobe through Chemical Synapses in Drosophila. Front Neural Circuits 2017; 11:30. [PMID: 28515683 PMCID: PMC5413558 DOI: 10.3389/fncir.2017.00030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/10/2017] [Indexed: 11/15/2022] Open
Abstract
In the insect olfactory system, odor information is transferred from the antennal lobe (AL) to higher brain areas by projection neurons (PNs) in multiple AL tracts (ALTs). In several species, one of the ALTs, the mediolateral ALT (mlALT), contains some GABAergic PNs; in the Drosophila brain, the great majority of ventral PNs (vPNs) are GABAergic and project through this tract to the lateral horn (LH). Most excitatory PNs (ePNs), project through the medial ALT (mALT) to the mushroom body (MB) and the LH. Recent studies have shown that GABAergic vPNs play inhibitory roles at their axon terminals in the LH. However, little is known about the properties and functions of vPNs at their dendritic branches in the AL. Here, we used optogenetic and patch clamp techniques to investigate the functional roles of vPNs in the AL. Surprisingly, our results show that specific activation of vPNs reliably elicits strong excitatory postsynaptic potentials (EPSPs) in ePNs. Moreover, the connections between vPNs and ePNs are mediated by direct chemical synapses. Neither pulses of GABA, nor pharmagological, or genetic blockade of GABAergic transmission gave results consistent with the involvement of GABA in vPN-ePN excitatory transmission. These unexpected results suggest new roles for the vPN population in olfactory information processing.
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Affiliation(s)
- Kazumichi Shimizu
- National Institute of Child Health and Human Development, National Institutes of HealthBethesda, MD, USA
| | - Mark Stopfer
- National Institute of Child Health and Human Development, National Institutes of HealthBethesda, MD, USA
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44
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Nicholl GCB, Jawad AK, Weymouth R, Zhang H, Beg AA. Pharmacological characterization of the excitatory 'Cys-loop' GABA receptor family in Caenorhabditis elegans. Br J Pharmacol 2017; 174:781-795. [PMID: 28146602 DOI: 10.1111/bph.13736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND AND PURPOSE Ionotropic GABA receptors are evolutionarily conserved proteins that mediate cellular and network inhibition in both vertebrates and invertebrates. A unique class of excitatory GABA receptors has been identified in several nematode species. Despite well-characterized functions in Caenorhabditis elegans, little is known about the pharmacology of the excitatory GABA receptors EXP-1 and LGC-35. Using a panel of compounds that differentially activate and modulate ionotropic GABA receptors, we investigated the agonist binding site and allosteric modulation of EXP-1 and LGC-35. EXPERIMENTAL APPROACH We used two-electrode voltage clamp recordings to characterize the pharmacological profile of EXP-1 and LGC-35 receptors expressed in Xenopus laevis oocytes. KEY RESULTS The pharmacology of EXP-1 and LGC-35 is different from that of GABAA and GABAA -ρ receptors. Both nematode receptors are resistant to the competitive orthosteric antagonist bicuculline and to classical ionotropic receptor pore blockers. The GABAA -ρ specific antagonist, TPMPA, was the only compound tested that potently inhibited EXP-1 and LGC-35. Neurosteroids have minimal effects on GABA-induced currents, but ethanol selectively potentiates LGC-35. CONCLUSIONS AND IMPLICATIONS The pharmacological properties of EXP-1 and LGC-35 more closely resemble the ionotropic GABAA -ρ family. However, EXP-1 and LGC-35 exhibit a unique profile that differs from vertebrate GABAA and GABAA -ρ receptors, insect GABA receptors and nematode GABA receptors. As a pair, EXP-1 and LGC-35 may be utilized to further understand the differential molecular mechanisms of agonist, antagonist and allosteric modulation at ionotropic GABA receptors and may aid in the design of new and more specific anthelmintics that target GABA neurotransmission.
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Affiliation(s)
| | - Ali K Jawad
- Neuroscience Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Haoming Zhang
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Asim A Beg
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA.,Neuroscience Program, University of Michigan, Ann Arbor, MI, USA
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45
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Long-Term High-Resolution Imaging of Developing C. elegans Larvae with Microfluidics. Dev Cell 2016; 40:202-214. [PMID: 28041904 DOI: 10.1016/j.devcel.2016.11.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/24/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Long-term studies of Caenorhabditis elegans larval development traditionally require tedious manual observations because larvae must move to develop, and existing immobilization techniques either perturb development or are unsuited for young larvae. Here, we present a simple microfluidic device to simultaneously follow development of ten C. elegans larvae at high spatiotemporal resolution from hatching to adulthood (∼3 days). Animals grown in microchambers are periodically immobilized by compression to allow high-quality imaging of even weak fluorescence signals. Using the device, we obtain cell-cycle statistics for C. elegans vulval development, a paradigm for organogenesis. We combine Nomarski and multichannel fluorescence microscopy to study processes such as cell-fate specification, cell death, and transdifferentiation throughout post-embryonic development. Finally, we generate time-lapse movies of complex neural arborization through automated image registration. Our technique opens the door to quantitative analysis of time-dependent phenomena governing cellular behavior during C. elegans larval development.
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Cymes GD, Grosman C. Identifying the elusive link between amino acid sequence and charge selectivity in pentameric ligand-gated ion channels. Proc Natl Acad Sci U S A 2016; 113:E7106-E7115. [PMID: 27791102 PMCID: PMC5111664 DOI: 10.1073/pnas.1608519113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Among neurotransmitter-gated ion channels, the superfamily of pentameric ligand-gated ion channels (pLGICs) is unique in that its members display opposite permeant-ion charge selectivities despite sharing the same structural fold. Although much effort has been devoted to the identification of the mechanism underlying the cation-versus-anion selectivity of these channels, a careful analysis of past work reveals that discrepancies exist, that different explanations for the same phenomenon have often been put forth, and that no consensus view has yet been reached. To elucidate the molecular basis of charge selectivity for the superfamily as a whole, we performed extensive mutagenesis and electrophysiological recordings on six different cation-selective and anion-selective homologs from vertebrate, invertebrate, and bacterial origin. We present compelling evidence for the critical involvement of ionized side chains-whether pore-facing or buried-rather than backbone atoms and propose a mechanism whereby not only their charge sign but also their conformation determines charge selectivity. Insertions, deletions, and residue-to-residue mutations involving nonionizable residues in the intracellular end of the pore seem to affect charge selectivity by changing the rotamer preferences of the ionized side chains in the first turn of the M2 α-helices. We also found that, upon neutralization of the charged residues in the first turn of M2, the control of charge selectivity is handed over to the many other ionized side chains that decorate the pore. This explains the long-standing puzzle as to why the neutralization of the intracellular-mouth glutamates affects charge selectivity to markedly different extents in different cation-selective pLGICs.
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Affiliation(s)
- Gisela D Cymes
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Claudio Grosman
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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Northcutt AJ, Lett KM, Garcia VB, Diester CM, Lane BJ, Marder E, Schulz DJ. Deep sequencing of transcriptomes from the nervous systems of two decapod crustaceans to characterize genes important for neural circuit function and modulation. BMC Genomics 2016; 17:868. [PMID: 27809760 PMCID: PMC5096308 DOI: 10.1186/s12864-016-3215-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 10/26/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Crustaceans have been studied extensively as model systems for nervous system function from single neuron properties to behavior. However, lack of molecular sequence information and tools have slowed the adoption of these physiological systems as molecular model systems. In this study, we sequenced and performed de novo assembly for the nervous system transcriptomes of two decapod crustaceans: the Jonah crab (Cancer borealis) and the American lobster (Homarus americanus). RESULTS Forty-two thousand, seven hundred sixty-six and sixty thousand, two hundred seventy-three contigs were assembled from C. borealis and H. americanus respectively, representing 9,489 and 11,061 unique coding sequences. From these transcripts, genes associated with neural function were identified and manually curated to produce a characterization of multiple gene families important for nervous system function. This included genes for 34 distinct ion channel types, 17 biogenic amine and 5 GABA receptors, 28 major transmitter receptor subtypes including glutamate and acetylcholine receptors, and 6 gap junction proteins - the Innexins. CONCLUSION With this resource, crustacean model systems are better poised for incorporation of modern genomic and molecular biology technologies to further enhance the interrogation of fundamentals of nervous system function.
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Affiliation(s)
- Adam J. Northcutt
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Kawasi M. Lett
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Virginia B. Garcia
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Clare M. Diester
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Brian J. Lane
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, MA USA
| | - David J. Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
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Li CW, Lo CC, Chen BS. Estimating Sensorimotor Mapping From Stimuli to Behaviors to Infer C. elegans Movements by Neural Transmission Ability Through Connectome Databases. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2016; 27:2229-2241. [PMID: 26415185 DOI: 10.1109/tnnls.2015.2475395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
One of the ultimate goals of computational neuroscience is to quantitatively connect between complex neural circuits and behaviors. In the past decades, the touch response circuit in Caenorhabditis elegans (C. elegans) has extensively been investigated in studies using genetically modified or laser-ablated worms. Synaptic connections, including chemical and electrical synapses, have been identified for most neurons in the C. elegans. However, we still do not know whether the empirically observed touch responses can be derived from connectome reconstructed from databases. To address this issue, we defined the transmission abilities (or levels) of neurons in a rate model in order to infer the behaviors of wild-type and ablated worms in response to posterior/nose/anterior touch stimuli. Our analysis showed that transmission abilities can be used to identify sensorimotor mapping from stimuli to movements and then to infer the C. elegans behaviors under simulations based on the perspective of decision-making, and provide useful information about how chemical and electronic synapses should be combined in the neural network movement analysis. This paper reveals an efficient tool that provided insights into the functions of complex neural circuits.
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Gendrel M, Atlas EG, Hobert O. A cellular and regulatory map of the GABAergic nervous system of C. elegans. eLife 2016; 5. [PMID: 27740909 PMCID: PMC5065314 DOI: 10.7554/elife.17686] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/22/2016] [Indexed: 12/16/2022] Open
Abstract
Neurotransmitter maps are important complements to anatomical maps and represent an invaluable resource to understand nervous system function and development. We report here a comprehensive map of neurons in the C. elegans nervous system that contain the neurotransmitter GABA, revealing twice as many GABA-positive neuron classes as previously reported. We define previously unknown glia-like cells that take up GABA, as well as 'GABA uptake neurons' which do not synthesize GABA but take it up from the extracellular environment, and we map the expression of previously uncharacterized ionotropic GABA receptors. We use the map of GABA-positive neurons for a comprehensive analysis of transcriptional regulators that define the GABA phenotype. We synthesize our findings of specification of GABAergic neurons with previous reports on the specification of glutamatergic and cholinergic neurons into a nervous system-wide regulatory map which defines neurotransmitter specification mechanisms for more than half of all neuron classes in C. elegans. DOI:http://dx.doi.org/10.7554/eLife.17686.001
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Affiliation(s)
- Marie Gendrel
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Emily G Atlas
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
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Competitive antagonists facilitate the recovery from desensitization of α1β2γ2 GABAA receptors expressed in Xenopus oocytes. Acta Pharmacol Sin 2016; 37:1020-30. [PMID: 27374488 DOI: 10.1038/aps.2016.50] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/07/2016] [Indexed: 01/22/2023] Open
Abstract
AIM The continuous presence of an agonist drives its receptor into a refractory state, termed desensitization. In this study, we tested the hypothesis that a competitive antagonist, SR95531, could facilitate the recovery of α1β2γ2 GABAA receptor from functional desensitization. METHODS α1β2γ2 GABAA receptors were expressed in Xenopus oocytes. GABA-evoked currents were recorded using two-electrode voltage-clamp technique. Drugs were applied through perfusion. RESULTS Long application of GABA (100 μmol/L) evoked a large peak current followed by a small amplitude steady-state current (desensitization). Co-application of SR95531 during the desensitization caused a larger rebound of GABA current after removal of SR95531. Furthermore, application of SR95531 after removal of GABA increased the rate of receptor recovery from desensitization, and the recovery time constant was decreased from 59±3.2 s to 33±1.6 s. SR95531-facilitated receptor recovery from desensitization was dependent on the perfusion duration of SR95531. It was also dependent on the concentration of SR95531, and the curve fitting with Hill equation revealed two potency components, which were similar to the two potency components in inhibition of the steady-state current by SR95531. Bicuculline caused similar facilitation of desensitization recovery. CONCLUSION SR95531 facilitates α1β2γ2 GABAA receptor recovery from desensitization, possibly through two mechanisms: binding to the desensitized receptor and converting it to the non-desensitized state, and binding to the resting state receptor and preventing re-desensitization.
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