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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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Rabinowitch I, Colón-Ramos DA, Krieg M. Understanding neural circuit function through synaptic engineering. Nat Rev Neurosci 2024; 25:131-139. [PMID: 38172626 DOI: 10.1038/s41583-023-00777-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2023] [Indexed: 01/05/2024]
Abstract
Synapses are a key component of neural circuits, facilitating rapid and specific signalling between neurons. Synaptic engineering - the synthetic insertion of new synaptic connections into in vivo neural circuits - is an emerging approach for neural circuit interrogation. This approach is especially powerful for establishing causality in neural circuit structure-function relationships, for emulating synaptic plasticity and for exploring novel patterns of circuit connectivity. Contrary to other approaches for neural circuit manipulation, synaptic engineering targets specific connections between neurons and functions autonomously with no user-controlled external activation. Synaptic engineering has been successfully implemented in several systems and in different forms, including electrical synapses constructed from ectopically expressed connexin gap junction proteins, synthetic optical synapses composed of presynaptic photon-emitting luciferase coupled with postsynaptic light-gated channels, and artificial neuropeptide signalling pathways. This Perspective describes these different methods and how they have been applied, and examines how the field may advance.
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Affiliation(s)
- Ithai Rabinowitch
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Daniel A Colón-Ramos
- Wu Tsai Institute, Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Michael Krieg
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
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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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Almoril-Porras A, Calvo AC, Niu L, Beagan J, Hawk JD, Aljobeh A, Wisdom EM, Ren I, Díaz-García M, Wang ZW, Colón-Ramos DA. Specific configurations of electrical synapses filter sensory information to drive choices in behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.551556. [PMID: 37577611 PMCID: PMC10418224 DOI: 10.1101/2023.08.01.551556] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Synaptic configurations in precisely wired circuits underpin how sensory information is processed by the nervous system, and the emerging animal behavior. This is best understood for chemical synapses, but far less is known about how electrical synaptic configurations modulate, in vivo and in specific neurons, sensory information processing and context-specific behaviors. We discovered that INX-1, a gap junction protein that forms electrical synapses, is required to deploy context-specific behavioral strategies during C. elegans thermotaxis behavior. INX-1 couples two bilaterally symmetric interneurons, and this configuration is required for the integration of sensory information during migration of animals across temperature gradients. In inx-1 mutants, uncoupled interneurons display increased excitability and responses to subthreshold temperature stimuli, resulting in abnormally longer run durations and context-irrelevant tracking of isotherms. Our study uncovers a conserved configuration of electrical synapses that, by increasing neuronal capacitance, enables differential processing of sensory information and the deployment of context-specific behavioral strategies.
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Affiliation(s)
- Agustin Almoril-Porras
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Ana C. Calvo
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut Health Center; Farmington, CT 06030, USA
| | - Jonathan Beagan
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Josh D. Hawk
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Ahmad Aljobeh
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Elias M. Wisdom
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Ivy Ren
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Malcom Díaz-García
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut Health Center; Farmington, CT 06030, USA
| | - Daniel A. Colón-Ramos
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
- Wu Tsai Institute, Yale University; New Haven, CT 06510, USA
- Marine Biological Laboratory; Woods Hole, MA, USA
- Instituto de Neurobiología, Recinto de Ciencias Médicas, Universidad de Puerto Rico; San Juan 00901, Puerto Rico
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5
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Choi U, Hu M, Zhang Q, Sieburth D. The head mesodermal cell couples FMRFamide neuropeptide signaling with rhythmic muscle contraction in C. elegans. Nat Commun 2023; 14:4218. [PMID: 37452027 PMCID: PMC10349088 DOI: 10.1038/s41467-023-39955-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
FMRFamides are evolutionarily conserved neuropeptides that play critical roles in behavior, energy balance, and reproduction. Here, we show that FMRFamide signaling from the nervous system is critical for the rhythmic activation of a single cell of previously unknown function, the head mesodermal cell (hmc) in C. elegans. Behavioral, calcium imaging, and genetic studies reveal that release of the FLP-22 neuropeptide from the AVL neuron in response to pacemaker signaling activates hmc every 50 s through an frpr-17 G protein-coupled receptor (GPCR) and a protein kinase A signaling cascade in hmc. hmc activation results in muscle contraction through coupling by gap junctions composed of UNC-9/Innexin. hmc activation is inhibited by the neuronal release of a second FMRFamide-like neuropeptide, FLP-9, which functions through its GPCR, frpr-21, in hmc. This study reveals a function for two opposing FMRFamide signaling pathways in controlling the rhythmic activation of a target cell through volume transmission.
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Affiliation(s)
- Ukjin Choi
- DSR graduate program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Mingxi Hu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Qixin Zhang
- MPHY program, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Derek Sieburth
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
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6
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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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7
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Intrinsic Sources and Functional Impacts of Asymmetry at Electrical Synapses. eNeuro 2022; 9:ENEURO.0469-21.2022. [PMID: 35135867 PMCID: PMC8925721 DOI: 10.1523/eneuro.0469-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/14/2022] [Accepted: 02/02/2022] [Indexed: 11/21/2022] Open
Abstract
Electrical synapses couple inhibitory neurons across the brain, underlying a variety of functions that are modifiable by activity. Despite recent advances, many functions and contributions of electrical synapses within neural circuitry remain underappreciated. Among these are the sources and impacts of electrical synapse asymmetry. Using multi-compartmental models of neurons coupled through dendritic electrical synapses, we investigated intrinsic factors that contribute to effective synaptic asymmetry and that result in modulation of spike timing and synchrony between coupled cells. We show that electrical synapse location along a dendrite, input resistance, internal dendritic resistance, or directional conduction of the electrical synapse itself each alter asymmetry as measured by coupling between cell somas. Conversely, we note that asymmetrical gap junction (GJ) conductance can be masked by each of these properties. Furthermore, we show that asymmetry modulates spike timing and latency of coupled cells by up to tens of milliseconds, depending on direction of conduction or dendritic location of the electrical synapse. Coordination of rhythmic activity between two cells also depends on asymmetry. These simulations illustrate that causes of asymmetry are diverse, may not be apparent in somatic measurements of electrical coupling, influence dendritic processing, and produce a variety of outcomes on spiking and synchrony of coupled cells. Our findings highlight aspects of electrical synapses that should always be included in experimental demonstrations of coupling, and when assembling simulated networks containing electrical synapses.
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