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Jiang Q, Zou W, Li S, Qiu X, Zhu L, Kang L, Müller U. Sequence variations and accessory proteins adapt TMC functions to distinct sensory modalities. Neuron 2024:S0896-6273(24)00448-3. [PMID: 38986620 DOI: 10.1016/j.neuron.2024.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 05/10/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024]
Abstract
Transmembrane channel-like (TMC) proteins are expressed throughout the animal kingdom and are thought to encode components of ion channels. Mammals express eight TMCs (mTMC1-8), two of which (mTMC1 and mTMC2) are subunits of mechanotransduction channels. C. elegans expresses two TMCs (TMC-1 and TMC-2), which mediate mechanosensation, egg laying, and alkaline sensing. The mechanisms by which nematode TMCs contribute to such diverse physiological processes and their functional relationship to mammalian mTMCs is unclear. Here, we show that association with accessory proteins tunes nematode TMC-1 to divergent sensory functions. In addition, distinct TMC-1 domains enable touch and alkaline sensing. Strikingly, these domains are segregated in mammals between mTMC1 and mTMC3. Consistent with these findings, mammalian mTMC1 can mediate mechanosensation in nematodes, while mTMC3 can mediate alkaline sensation. We conclude that sequence diversification and association with accessory proteins has led to the emergence of TMC protein complexes with diverse properties and physiological functions.
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Affiliation(s)
- Qiang Jiang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wenjuan Zou
- Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310053, Zhejiang, China
| | - Shitian Li
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Linhui Zhu
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Lijun Kang
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Yiwu 322000, China.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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2
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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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Wu Y, Zhang D, Liu J, Jiang J, Xie K, Wu L, Leng Y, Liang P, Zhu T, Zhou C. Activity of the Sodium Leak Channel Maintains the Excitability of Paraventricular Thalamus Glutamatergic Neurons to Resist Anesthetic Effects of Sevoflurane in Mice. Anesthesiology 2024; 141:56-74. [PMID: 38625708 DOI: 10.1097/aln.0000000000005015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
BACKGROUND Stimulation of the paraventricular thalamus has been found to enhance anesthesia recovery; however, the underlying molecular mechanism by which general anesthetics modulate paraventricular thalamus is unclear. This study aimed to test the hypothesis that the sodium leak channel (NALCN) maintains neuronal activity in the paraventricular thalamus to resist anesthetic effects of sevoflurane in mice. METHODS Chemogenetic and optogenetic manipulations, in vivo multiple-channel recordings, and electroencephalogram recordings were used to investigate the role of paraventricular thalamus neuronal activity in sevoflurane anesthesia. Virus-mediated knockdown and/or overexpression was applied to determine how NALCN influenced excitability of paraventricular thalamus glutamatergic neurons under sevoflurane. Viral tracers and local field potentials were used to explore the downstream pathway. RESULTS Single neuronal spikes in the paraventricular thalamus were suppressed by sevoflurane anesthesia and recovered during emergence. Optogenetic activation of paraventricular thalamus glutamatergic neurons shortened the emergence period from sevoflurane anesthesia, while chemogenetic inhibition had the opposite effect. Knockdown of the NALCN in the paraventricular thalamus delayed the emergence from sevoflurane anesthesia (recovery time: from 24 ± 14 to 64 ± 19 s, P < 0.001; concentration for recovery of the righting reflex: from 1.13% ± 0.10% to 0.97% ± 0.13%, P < 0.01). As expected, the overexpression of the NALCN in the paraventricular thalamus produced the opposite effects. At the circuit level, knockdown of the NALCN in the paraventricular thalamus decreased the neuronal activity of the nucleus accumbens, as indicated by the local field potential and decreased single neuronal spikes in the nucleus accumbens. Additionally, the effects of NALCN knockdown in the paraventricular thalamus on sevoflurane actions were reversed by optical stimulation of the nucleus accumbens. CONCLUSIONS Activity of the NALCN maintains the excitability of paraventricular thalamus glutamatergic neurons to resist the anesthetic effects of sevoflurane in mice. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Yujie Wu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jingyao Jiang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Keyu Xie
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Lin Wu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yu Leng
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China; Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
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Chen HW, Ma CP, Chin E, Chen YT, Wang TC, Kuo YP, Su CH, Huang PJ, Tan BCM. Imbalance in Unc80 RNA Editing Disrupts Dynamic Neuronal Activity and Olfactory Perception. Int J Mol Sci 2024; 25:5985. [PMID: 38892173 PMCID: PMC11172567 DOI: 10.3390/ijms25115985] [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: 03/29/2024] [Revised: 05/22/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
A-to-I RNA editing, catalyzed by the ADAR protein family, significantly contributes to the diversity and adaptability of mammalian RNA signatures, aligning with developmental and physiological needs. Yet, the functions of many editing sites are still to be defined. The Unc80 gene stands out in this context due to its brain-specific expression and the evolutionary conservation of its codon-altering editing event. The precise biological functions of Unc80 and its editing, however, are still largely undefined. In this study, we first demonstrated that Unc80 editing occurs in an ADAR2-dependent manner and is exclusive to the brain. By employing the CRISPR/Cas9 system to generate Unc80 knock-in mouse models that replicate the natural editing variations, our findings revealed that mice with the "gain-of-editing" variant (Unc80G/G) exhibit heightened basal neuronal activity in critical olfactory regions, compared to the "loss-of-editing" (Unc80S/S) counterparts. Moreover, an increase in glutamate levels was observed in the olfactory bulbs of Unc80G/G mice, indicating altered neurotransmitter dynamics. Behavioral analysis of odor detection revealed distinctive responses to novel odors-both Unc80 deficient (Unc80+/-) and Unc80S/S mice demonstrated prolonged exploration times and heightened dishabituation responses. Further elucidating the olfactory connection of Unc80 editing, transcriptomic analysis of the olfactory bulb identified significant alterations in gene expression that corroborate the behavioral and physiological findings. Collectively, our research advances the understanding of Unc80's neurophysiological functions and the impact of its editing on the olfactory sensory system, shedding light on the intricate molecular underpinnings of olfactory perception and neuronal activity.
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Affiliation(s)
- Hui-Wen Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
| | - Chung-Pei Ma
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
| | - En Chin
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
| | - Yi-Tung Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan;
| | - Teh-Cheng Wang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
| | - Yu-Ping Kuo
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan;
| | - Chia-Hao Su
- Center for General Education, Chang Gung University, Taoyuan 333, Taiwan;
- Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
| | - Po-Jung Huang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
- Genomic Medicine Core Laboratory, Lin-Kou Medical Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
| | - Bertrand Chin-Ming Tan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (H.-W.C.); (C.-P.M.); (E.C.); (Y.-T.C.); (P.-J.H.)
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
- Division of Colon and Rectal Surgery, Lin-Kou Medical Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
- Department of Neurosurgery, Lin-Kou Medical Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
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Schott K, Usher SG, Serra O, Carnevale V, Pless SA, Chua HC. Unplugging lateral fenestrations of NALCN reveals a hidden drug binding site within the pore region. Proc Natl Acad Sci U S A 2024; 121:e2401591121. [PMID: 38787877 PMCID: PMC11145269 DOI: 10.1073/pnas.2401591121] [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: 01/23/2024] [Accepted: 04/09/2024] [Indexed: 05/26/2024] Open
Abstract
The sodium (Na+) leak channel (NALCN) is a member of the four-domain voltage-gated cation channel family that includes the prototypical voltage-gated sodium and calcium channels (NaVs and CaVs, respectively). Unlike NaVs and CaVs, which have four lateral fenestrations that serve as routes for lipophilic compounds to enter the central cavity to modulate channel function, NALCN has bulky residues (W311, L588, M1145, and Y1436) that block these openings. Structural data suggest that occluded fenestrations underlie the pharmacological resistance of NALCN, but functional evidence is lacking. To test this hypothesis, we unplugged the fenestrations of NALCN by substituting the four aforementioned residues with alanine (AAAA) and compared the effects of NaV, CaV, and NALCN blockers on both wild-type (WT) and AAAA channels. Most compounds behaved in a similar manner on both channels, but phenytoin and 2-aminoethoxydiphenyl borate (2-APB) elicited additional, distinct responses on AAAA channels. Further experiments using single alanine mutants revealed that phenytoin and 2-APB enter the inner cavity through distinct fenestrations, implying structural specificity to their modes of access. Using a combination of computational and functional approaches, we identified amino acid residues critical for 2-APB activity, supporting the existence of drug binding site(s) within the pore region. Intrigued by the activity of 2-APB and its analogues, we tested compounds containing the diphenylmethane/amine moiety on WT channels. We identified clinically used drugs that exhibited diverse activity, thus expanding the pharmacological toolbox for NALCN. While the low potencies of active compounds reiterate the pharmacological resistance of NALCN, our findings lay the foundation for rational drug design to develop NALCN modulators with refined properties.
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Affiliation(s)
- Katharina Schott
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Samuel George Usher
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Oscar Serra
- Department of Biology, Temple University, Philadelphia, PA19122
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA19122
- Institute of Computational Molecular Science, Temple University, Philadelphia, PA19122
| | - Vincenzo Carnevale
- Department of Biology, Temple University, Philadelphia, PA19122
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA19122
- Institute of Computational Molecular Science, Temple University, Philadelphia, PA19122
| | - Stephan Alexander Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
| | - Han Chow Chua
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen2100, Denmark
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Meng J, Ahamed T, Yu B, Hung W, EI Mouridi S, Wang Z, Zhang Y, Wen Q, Boulin T, Gao S, Zhen M. A tonically active master neuron modulates mutually exclusive motor states at two timescales. SCIENCE ADVANCES 2024; 10:eadk0002. [PMID: 38598630 PMCID: PMC11006214 DOI: 10.1126/sciadv.adk0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 03/07/2024] [Indexed: 04/12/2024]
Abstract
Continuity of behaviors requires animals to make smooth transitions between mutually exclusive behavioral states. Neural principles that govern these transitions are not well understood. Caenorhabditis elegans spontaneously switch between two opposite motor states, forward and backward movement, a phenomenon thought to reflect the reciprocal inhibition between interneurons AVB and AVA. Here, we report that spontaneous locomotion and their corresponding motor circuits are not separately controlled. AVA and AVB are neither functionally equivalent nor strictly reciprocally inhibitory. AVA, but not AVB, maintains a depolarized membrane potential. While AVA phasically inhibits the forward promoting interneuron AVB at a fast timescale, it maintains a tonic, extrasynaptic excitation on AVB over the longer timescale. We propose that AVA, with tonic and phasic activity of opposite polarities on different timescales, acts as a master neuron to break the symmetry between the underlying forward and backward motor circuits. This master neuron model offers a parsimonious solution for sustained locomotion consisted of mutually exclusive motor states.
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Affiliation(s)
- Jun Meng
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Tosif Ahamed
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Bin Yu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Sonia EI Mouridi
- University Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, 69008 Lyon, France
| | - Zezhen Wang
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Yongning Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Quan Wen
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Thomas Boulin
- University Claude Bernard Lyon 1, MeLiS, CNRS UMR 5284, INSERM U1314, 69008 Lyon, France
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mei Zhen
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
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7
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Schott K, Usher SG, Serra O, Carnevale V, Pless SA, Chua HC. Unplugging lateral fenestrations of NALCN reveals a hidden drug binding site within the pore module. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.12.536537. [PMID: 38328210 PMCID: PMC10849497 DOI: 10.1101/2023.04.12.536537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The sodium (Na + ) leak channel (NALCN) is a member of the four-domain voltage-gated cation channel family that includes the prototypical voltage-gated sodium and calcium channels (Na V s and Ca V s, respectively). Unlike Na V s and Ca V s, which have four lateral fenestrations that serve as routes for lipophilic compounds to enter the central cavity to modulate channel function, NALCN has bulky residues (W311, L588, M1145 and Y1436) that block these openings. Structural data suggest that oc-cluded lateral fenestrations underlie the pharmacological resistance of NALCN to lipophilic compounds, but functional evidence is lacking. To test this hypothesis, we unplugged the fenestrations of NALCN by substituting the four aforementioned resi-dues with alanine (AAAA) and compared the effects of Na V , Ca V and NALCN block-ers on both wild-type (WT) and AAAA channels. Most compounds behaved in a simi-lar manner on both channels, but phenytoin and 2-aminoethoxydiphenyl borate (2-APB) elicited additional, distinct responses on AAAA channels. Further experiments using single alanine mutants revealed that phenytoin and 2-APB enter the inner cav-ity through distinct fenestrations, implying structural specificity to their modes of ac-cess. Using a combination of computational and functional approaches, we identified amino acid residues critical for 2-APB activity, supporting the existence of drug bind-ing site(s) within the pore region. Intrigued by the activity of 2-APB and its ana-logues, we tested additional compounds containing the diphenylmethane/amine moiety on WT channels. We identified compounds from existing clinically used drugs that exhibited diverse activity, thus expanding the pharmacological toolbox for NALCN. While the low potencies of active compounds reiterate the resistance of NALCN to pharmacological targeting, our findings lay the foundation for rational drug design to develop NALCN modulators with refined properties. Significance statement The sodium leak channel (NALCN) is essential for survival: mutations cause life-threatening developmental disorders in humans. However, no treatment is currently available due to the resistance of NALCN to pharmacological targeting. One likely reason is that the lateral fenestrations, a common route for clinically used drugs to enter and block related ion channels, are occluded in NALCN. Using a combination of computational and functional approaches, we unplugged the fenestrations of NALCN which led us to the first molecularly defined drug binding site within the pore region. Besides that, we also identified additional NALCN modulators from existing clinically used therapeutics, thus expanding the pharmacological toolbox for this leak channel.
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8
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Zhang D, Wei Y. Role of sodium leak channel (NALCN) in sensation and pain: an overview. Front Pharmacol 2024; 14:1349438. [PMID: 38273833 PMCID: PMC10808581 DOI: 10.3389/fphar.2023.1349438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 12/29/2023] [Indexed: 01/27/2024] Open
Abstract
The sodium leak channel (NALCN) is widely expressed in the central nervous system and plays a pivotal role in regulating the resting membrane potential (RMP) by mediating the Na+ leak current. NALCN was first reported in 1999, and since then, increasing evidence has provided insights into the structure and functions of NALCN. As an essential component of neuronal background currents, NALCN has been shown to be involved in many important physiological functions, particularly in the respiratory rhythm, as NALCN mutant mice have a severely disrupted respiratory rhythm and die within 24 h of birth. Many patients with NALCN mutations also develop serious clinical syndromes, such as severe hypotonia, speech impairment, and cognitive delay. Recently, emerging studies have clarified the human NALCN structure and revealed additional properties and functions of NALCN. For instance, accumulating evidence highlights that the NALCN is involved in normal sensation and pain. Here, we review the current literature and summarize the role of the NALCN in sensation and pain.
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Affiliation(s)
- Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yiyong Wei
- Department of Anesthesiology, Longgang District Maternity and Child Healthcare Hospital of Shenzhen City (Longgang Maternity and Child Institute of Shantou University Medical College), Shenzhen, China
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Ngodup T, Irie T, Elkins SP, Trussell LO. The Na + leak channel NALCN controls spontaneous activity and mediates synaptic modulation by α2-adrenergic receptors in auditory neurons. eLife 2024; 12:RP89520. [PMID: 38197879 PMCID: PMC10945507 DOI: 10.7554/elife.89520] [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] [Indexed: 01/11/2024] Open
Abstract
Cartwheel interneurons of the dorsal cochlear nucleus (DCN) potently suppress multisensory signals that converge with primary auditory afferent input, and thus regulate auditory processing. Noradrenergic fibers from locus coeruleus project to the DCN, and α2-adrenergic receptors inhibit spontaneous spike activity but simultaneously enhance synaptic strength in cartwheel cells, a dual effect leading to enhanced signal-to-noise for inhibition. However, the ionic mechanism of this striking modulation is unknown. We generated a glycinergic neuron-specific knockout of the Na+ leak channel NALCN in mice and found that its presence was required for spontaneous firing in cartwheel cells. Activation of α2-adrenergic receptors inhibited both NALCN and spike generation, and this modulation was absent in the NALCN knockout. Moreover, α2-dependent enhancement of synaptic strength was also absent in the knockout. GABAB receptors mediated inhibition through NALCN as well, acting on the same population of channels as α2 receptors, suggesting close apposition of both receptor subtypes with NALCN. Thus, multiple neuromodulatory systems determine the impact of synaptic inhibition by suppressing the excitatory leak channel, NALCN.
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Affiliation(s)
- Tenzin Ngodup
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
| | - Tomohiko Irie
- Department of Physiology, Kitasato University School of MedicineSagamiharaJapan
| | - Seán P Elkins
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
| | - Laurence O Trussell
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
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Monteil A, Guérineau NC, Gil-Nagel A, Parra-Diaz P, Lory P, Senatore A. New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN. Physiol Rev 2024; 104:399-472. [PMID: 37615954 DOI: 10.1152/physrev.00014.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.
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Affiliation(s)
- Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Antonio Gil-Nagel
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Paloma Parra-Diaz
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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11
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Ngodup T, Irie T, Elkins S, Trussell LO. The Na + leak channel NALCN controls spontaneous activity and mediates synaptic modulation by α2-adrenergic receptors in auditory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.23.546323. [PMID: 37987013 PMCID: PMC10659375 DOI: 10.1101/2023.06.23.546323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Cartwheel interneurons of the dorsal cochlear nucleus (DCN) potently suppress multisensory signals that converge with primary auditory afferent input, and thus regulate auditory processing. Noradrenergic fibers from locus coeruleus project to the DCN, and α2-adrenergic receptors inhibit spontaneous spike activity but simultaneously enhance synaptic strength in cartwheel cells, a dual effect leading to enhanced signal-to-noise for inhibition. However, the ionic mechanism of this striking modulation is unknown. We generated a glycinergic neuron-specific knockout of the Na+ leak channel NALCN, and found that its presence was required for spontaneous firing in cartwheel cells. Activation of α2-adrenergic receptors inhibited both NALCN and spike generation, and this modulation was absent in the NALCN knockout. Moreover, α2-dependent enhancement of synaptic strength was also absent in the knockout. GABAB receptors mediated inhibition through NALCN as well, acting on the same population of channels as α2 receptors, suggesting close apposition of both receptor subtypes with NALCN. Thus, multiple neuromodulatory systems determine the impact of synaptic inhibition by suppressing the excitatory leak channel, NALCN.
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Affiliation(s)
- Tenzin Ngodup
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland OR USA
| | - Tomohiko Irie
- Department of Physiology, Kitasato University School of Medicine, Sagamihara, Japan
| | - Sean Elkins
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland OR USA
| | - Laurence O Trussell
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland OR USA
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12
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Bayat A, Liu Z, Luo S, Fenger CD, Højte AF, Isidor B, Cogne B, Larson A, Zanus C, Faletra F, Keren B, Musante L, Gourfinkel-An I, Perrine C, Demily C, Lesca G, Liao W, Ren D. A new neurodevelopmental disorder linked to heterozygous variants in UNC79. Genet Med 2023; 25:100894. [PMID: 37183800 DOI: 10.1016/j.gim.2023.100894] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 05/16/2023] Open
Abstract
PURPOSE The "NALCN channelosome" is an ion channel complex that consists of multiple proteins, including NALCN, UNC79, UNC80, and FAM155A. Only a small number of individuals with a neurodevelopmental syndrome have been reported with disease causing variants in NALCN and UNC80. However, no pathogenic UNC79 variants have been reported, and in vivo function of UNC79 in humans is largely unknown. METHODS We used international gene-matching efforts to identify patients harboring ultrarare heterozygous loss-of-function UNC79 variants and no other putative responsible genes. We used genetic manipulations in Drosophila and mice to test potential causal relationships between UNC79 variants and the pathology. RESULTS We found 6 unrelated and affected patients with UNC79 variants. Five patients presented with overlapping neurodevelopmental features, including mild to moderate intellectual disability and a mild developmental delay, whereas a single patient reportedly had normal cognitive and motor development but was diagnosed with epilepsy and autistic features. All displayed behavioral issues and 4 patients had epilepsy. Drosophila with UNC79 knocked down displayed induced seizure-like phenotype. Mice with a heterozygous loss-of-function variant have a developmental delay in body weight compared with wild type. In addition, they have impaired ability in learning and memory. CONCLUSION Our results demonstrate that heterozygous loss-of-function UNC79 variants are associated with neurologic pathologies.
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Affiliation(s)
- Allan Bayat
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark; Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Zhenjiang Liu
- Department of Biology, University of Pennsylvania, Philadelphia, PA; National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, China
| | - Sheng Luo
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark; Amplexa Genetics A/S, Odense, Denmark
| | - Anne F Højte
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark
| | - Bertrand Isidor
- Department of Genetics, CHU Nantes, Nantes, France; University of Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Benjamin Cogne
- Department of Genetics, CHU Nantes, Nantes, France; University of Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Austin Larson
- University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
| | - Caterina Zanus
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo," Trieste, Italy
| | - Flavio Faletra
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo," Trieste, Italy
| | - Boris Keren
- Department of Neurology, Epileptology Unit, Reference Center for Rare Epilepsies, Sorbonne University, La Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Luciana Musante
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo," Trieste, Italy
| | - Isabelle Gourfinkel-An
- Department of Neurology, Epileptology Unit, Reference Center for Rare Epilepsies, Sorbonne University, La Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - Charles Perrine
- Department of Medical Genetics, Pitié-Salpêtrière Hospital, AP-HP, University of Sorbonne, Paris, France
| | - Caroline Demily
- GénoPsy, Reference Center for Diagnosis and Management of Genetic Psychiatric Disorders, Vinatier Hospital Center and EDR-Psy Team (National Center for Scientific Research and Lyon 1 Claude Bernard University), Lyon, France; iMIND Excellence Center for Autism and Neurodevelopmental Disorders, Lyon, France
| | - Gaeton Lesca
- Department of Medical Genetics, University Hospital of Lyon, Lyon, France
| | - Weiping Liao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA
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13
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Al-Mazidi S, Al-Ayadhi L, Alqahtany F, Abualnaja A, Alzarroug A, Alharbi T, Farhat K, AlMnaizel A, El-Ansary A. The possible role of sodium leakage channel localization factor-1 in the pathophysiology and severity of autism spectrum disorders. Sci Rep 2023; 13:9747. [PMID: 37328585 PMCID: PMC10275888 DOI: 10.1038/s41598-023-36953-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 06/13/2023] [Indexed: 06/18/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social, stereotypical, and repetitive behaviors. Neural dysregulation was proposed as an etiological factor in ASD. The sodium leakage channel (NCA), regulated by NLF-1 (NCA localization factor-1), has a major role in maintaining the physiological excitatory function of neurons. We aimed to examine the level of NLF-1 in ASD children and correlate it with the severity of the disease. We examined the plasma levels of NLF-1 in 80 ASD and neurotypical children using ELISA. The diagnosis and severity of ASD were based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), Childhood Autism Rating Score, Social Responsiveness Scale, and Short Sensory Profile. Then, we compared the levels of NLF-1 with the severity of the disease and behavioral and sensory symptoms. Our results showed a significant decrease in the plasma levels of NLF-1 in ASD children compared to neurotypical children (p < 0.001). Additionally, NLF-1 was significantly correlated with the severity of the behavioral symptoms of ASD (p < 0.05). The low levels of NLF-1 in ASD children potentially affect the severity of their behavioral symptoms by reducing neuron excitability through NCA. These novel findings open a new venue for pharmacological and possible genetic research involving NCA in ASD children.
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Affiliation(s)
- Sarah Al-Mazidi
- Physiology Department, College of Medicine, Imam Mohammad Ibn Saud Islamic University, P.O.Box: 5701, Riyadh, 11432, Saudi Arabia.
| | - Laila Al-Ayadhi
- Physiology, King Saud University College of Medicine, Riyadh, Saudi Arabia
- Autism Research and Treatment Center, King Saud University College of Medicine, Riyadh, Saudi Arabia
| | - Fatmah Alqahtany
- Hematopathology Unit, Department of Pathology, College of Medicine, King Saud University, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Amani Abualnaja
- College of Medicine, Imam Muhammad bin Saud Islamic University, Riyadh, Saudi Arabia
| | - Abdullah Alzarroug
- College of Medicine, Imam Muhammad bin Saud Islamic University, Riyadh, Saudi Arabia
| | - Turki Alharbi
- College of Medicine, Imam Muhammad bin Saud Islamic University, Riyadh, Saudi Arabia
| | - Karim Farhat
- Cancer Research Chair, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ahmad AlMnaizel
- Research office, John Hopkins Aramco Healthcare, Dahran, Saudi Arabia
| | - Afaf El-Ansary
- Autism Research and Treatment Center, King Saud University College of Medicine, Riyadh, Saudi Arabia
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14
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Pathophysiology of Diverticular Disease: From Diverticula Formation to Symptom Generation. Int J Mol Sci 2022; 23:ijms23126698. [PMID: 35743141 PMCID: PMC9223421 DOI: 10.3390/ijms23126698] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 01/04/2023] Open
Abstract
Diverticular disease is a common clinical problem, particularly in industrialized countries. In most cases, colonic diverticula remain asymptomatic throughout life and sometimes are found incidentally during colonic imaging in colorectal cancer screening programs in otherwise healthy subjects. Nonetheless, roughly 25% of patients bearing colonic diverticula develop clinical manifestations. Abdominal symptoms associated with diverticula in the absence of inflammation or complications are termed symptomatic uncomplicated diverticular disease (SUDD). The pathophysiology of diverticular disease as well as the mechanisms involved in the shift from an asymptomatic condition to a symptomatic one is still poorly understood. It is accepted that both genetic factors and environment, as well as intestinal microenvironment alterations, have a role in diverticula development and in the different phenotypic expressions of diverticular disease. In the present review, we will summarize the up-to-date knowledge on the pathophysiology of diverticula and their different clinical setting, including diverticulosis and SUDD.
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15
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Kang Y, Chen L. Structure and mechanism of NALCN-FAM155A-UNC79-UNC80 channel complex. Nat Commun 2022; 13:2639. [PMID: 35550517 PMCID: PMC9098444 DOI: 10.1038/s41467-022-30403-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/27/2022] [Indexed: 11/09/2022] Open
Abstract
NALCN channel mediates sodium leak currents and is important for maintaining proper resting membrane potential. NALCN and FAM155A form the core complex of the channel, the activity of which essentially depends on the presence of both UNC79 and UNC80, two auxiliary proteins. NALCN, FAM155A, UNC79, and UNC80 co-assemble into a large hetero-tetrameric channel complex. Genetic mutations of NALCN channel components lead to neurodevelopmental diseases. However, the structure and mechanism of the intact channel complex remain elusive. Here, we present the cryo-EM structure of the mammalian NALCN-FAM155A-UNC79-UNC80 quaternary complex. The structure shows that UNC79-UNC80 form a large piler-shaped heterodimer which was tethered to the intracellular side of the NALCN channel through tripartite interactions with the cytoplasmic loops of NALCN. Two interactions are essential for proper cell surface localization of NALCN. The other interaction relieves the self-inhibition of NALCN by pulling the auto-inhibitory CTD Interacting Helix (CIH) out of its binding site. Our work defines the structural mechanism of NALCN modulation by UNC79 and UNC80.
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Affiliation(s)
- Yunlu Kang
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking. University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, 100871, China.,National Biomedical Imaging Center, Peking University, Beijing, 100871, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking. University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, 100871, China. .,National Biomedical Imaging Center, Peking University, Beijing, 100871, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China. .,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
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16
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Zhou C, Zhou Q, He X, He Y, Wang X, Zhu X, Zhang Y, Ma L. Differential modulation of C. elegans motor behavior by NALCN and two-pore domain potassium channels. PLoS Genet 2022; 18:e1010126. [PMID: 35482723 PMCID: PMC9049526 DOI: 10.1371/journal.pgen.1010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 02/28/2022] [Indexed: 11/18/2022] Open
Abstract
Two-pore domain potassium channels (K2P) are a large family of “background” channels that allow outward “leak” of potassium ions. The NALCN/UNC80/UNC79 complex is a non-selective channel that allows inward flow of sodium and other cations. It is unclear how K2Ps and NALCN differentially modulate animal behavior. Here, we found that loss of function (lf) in the K2P gene twk-40 suppressed the reduced body curvatures of C. elegans NALCN(lf) mutants. twk-40(lf) caused a deep body curvature and extended backward locomotion, and these phenotypes appeared to be associated with neuron-specific expression of twk-40 and distinct twk-40 transcript isoforms. To survey the functions of other less studied K2P channels, we examined loss-of-function mutants of 13 additional twk genes expressed in the motor circuit and detected defective body curvature and/or locomotion in mutants of twk-2, twk-17, twk-30, twk-48, unc-58, and the previously reported twk-7. We generated presumptive gain-of-function (gf) mutations in twk-40, twk-2, twk-7, and unc-58 and found that they caused paralysis. Further analyses detected variable genetic interactions between twk-40 and other twk genes, an interdependence between twk-40 and twk-2, and opposite behavioral effects between NALCN and twk-2, twk-7, or unc-58. Finally, we found that the hydrophobicity/hydrophilicity property of TWK-40 residue 159 could affect the channel activity. Together, our study identified twk-40 as a novel modulator of the motor behavior, uncovered potential behavioral effects of five other K2P genes and suggests that NALCN and some K2Ps can oppositely affect C. elegans behavior.
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Affiliation(s)
- Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Qian Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaohui He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yunxia He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaoqin Wang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaowei Zhu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yujia Zhang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Molecular Precision Medicine, Central South University, Changsha, Hunan, China
- * E-mail:
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17
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Yu B, Wang Y, Gao S. Motor Rhythm Dissection From the Backward Circuit in C. elegans. Front Mol Neurosci 2022; 15:845733. [PMID: 35370545 PMCID: PMC8966088 DOI: 10.3389/fnmol.2022.845733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/26/2022] [Indexed: 11/28/2022] Open
Abstract
Motor rhythm is initiated and sustained by oscillatory neuronal activity. We recently discovered that the A-class excitatory motor neurons (MNs) (A-MNs) function as intrinsic oscillators. They drive backward locomotion by generating rhythmic postsynaptic currents (rPSCs) in body wall muscles. Molecular underpinning of the rPSCs, however, is not fully elucidated. We report here that there are three types of the rPSC patterns, namely the phasic, tonic, and long-lasting, each with distinct kinetics and channel-dependence. The Na+ leak channel is required for all rPSC patterns. The tonic rPSCs exhibit strong dependence on the high-voltage-gated Ca2+ channels. Three K+ channels, the BK-type Ca2+-activated K+ channel, Na+-activated K+ channel, and voltage-gated K+ channel (Kv4), primarily inhibit tonic and long-lasting rPSCs with varying degrees and preferences. The elaborate regulation of rPSCs by different channels, through increasing or decreasing the rPSCs frequency and/or charge, correlates with the changes in the reversal velocity for respective channel mutants. The molecular dissection of different A-MNs-rPSC components therefore reveals different mechanisms for multiplex motor rhythm.
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Affiliation(s)
- 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, China
| | - Ya Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Shangbang Gao,
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18
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Structural architecture of the human NALCN channelosome. Nature 2022; 603:180-186. [PMID: 34929720 DOI: 10.1038/s41586-021-04313-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/07/2021] [Indexed: 11/08/2022]
Abstract
Depolarizing sodium (Na+) leak currents carried by the NALCN channel regulate the resting membrane potential of many neurons to modulate respiration, circadian rhythm, locomotion and pain sensitivity1-8. NALCN requires FAM155A, UNC79 and UNC80 to function, but the role of these auxiliary subunits is not understood3,7,9-12. NALCN, UNC79 and UNC80 are essential in rodents2,9,13, and mutations in human NALCN and UNC80 cause severe developmental and neurological disease14,15. Here we determined the structure of the NALCN channelosome, an approximately 1-MDa complex, as fundamental aspects about the composition, assembly and gating of this channelosome remain obscure. UNC79 and UNC80 are massive HEAT-repeat proteins that form an intertwined anti-parallel superhelical assembly, which docks intracellularly onto the NALCN-FAM155A pore-forming subcomplex. Calmodulin copurifies bound to the carboxy-terminal domain of NALCN, identifying this region as a putative modulatory hub. Single-channel analyses uncovered a low open probability for the wild-type complex, highlighting the tightly closed S6 gate in the structure, and providing a basis to interpret the altered gating properties of disease-causing variants. Key constraints between the UNC79-UNC80 subcomplex and the NALCN DI-DII and DII-DIII linkers were identified, leading to a model of channelosome gating. Our results provide a structural blueprint to understand the physiology of the NALCN channelosome and a template for drug discovery to modulate the resting membrane potential.
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19
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Multi-Modal Regulation of Circadian Physiology by Interactive Features of Biological Clocks. BIOLOGY 2021; 11:biology11010021. [PMID: 35053019 PMCID: PMC8772734 DOI: 10.3390/biology11010021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 12/26/2022]
Abstract
The circadian clock is a fundamental biological timing mechanism that generates nearly 24 h rhythms of physiology and behaviors, including sleep/wake cycles, hormone secretion, and metabolism. Evolutionarily, the endogenous clock is thought to confer living organisms, including humans, with survival benefits by adapting internal rhythms to the day and night cycles of the local environment. Mirroring the evolutionary fitness bestowed by the circadian clock, daily mismatches between the internal body clock and environmental cycles, such as irregular work (e.g., night shift work) and life schedules (e.g., jet lag, mistimed eating), have been recognized to increase the risk of cardiac, metabolic, and neurological diseases. Moreover, increasing numbers of studies with cellular and animal models have detected the presence of functional circadian oscillators at multiple levels, ranging from individual neurons and fibroblasts to brain and peripheral organs. These oscillators are tightly coupled to timely modulate cellular and bodily responses to physiological and metabolic cues. In this review, we will discuss the roles of central and peripheral clocks in physiology and diseases, highlighting the dynamic regulatory interactions between circadian timing systems and multiple metabolic factors.
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20
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Rong Z, Luo Z, Fu Z, Zhang P, Li T, Zhang J, Zhu Z, Yu Z, Li Q, Qiu Z, Huang C. The novel circSLC6A6/miR-1265/C2CD4A axis promotes colorectal cancer growth by suppressing p53 signaling pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:324. [PMID: 34656159 PMCID: PMC8520208 DOI: 10.1186/s13046-021-02126-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/04/2021] [Indexed: 01/21/2023]
Abstract
Background Colorectal cancer (CRC) is one of the most frequent malignancy and a leading cause of cancer-related deaths. Therefore, further researches are required to identify novel and more effective diagnoses and to identify molecular targets in treatment of CRC. Methods C2CD4A expression in CRC tissues and cell lines was detected by qRT-PCR and western blot. The biological functions of C2CD4A were performed both in vitro and in vivo. Western blot, cDNA array, IP-MS, Co-immunoprecipitation assay, and Ubiquitination assay were used to analyze the interaction between C2CD4A and p53. Bioinformatics analysis, FISH, RNA sequencing, luciferase reporter assay, RNA immunoprecipitation, RNA pull-down and rescue experiments, were deployed to detect upstream regulation mechanism of C2CD4A. Results C2CD4A was elevated in CRC tissues compared with adjacent normal colorectal tissues. C2CD4A knockdown significantly promoted cell apoptosis and with inhibited proliferation in vitro, and tumorigenicity in vivo, whereas C2CD4A overexpression led to opposite effects. Moreover, circSLC6A6 was upregulated and shown to positively regulate C2CD4A expression via sponging miR-1265. Fundamentally, C2CD4A inhibited p53 signaling pathway through interacting with p53 and increasing its ubiquitination and degradation. Conclusion Our results identified that circSLC6A6/miR-1265/C2CD4A axis, which was involved in CRC via the p53 signaling pathway, may serve as a therapeutic target for CRC. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-021-02126-y.
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Affiliation(s)
- Zeyin Rong
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Zai Luo
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Zhongmao Fu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Pengshan Zhang
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Tengfei Li
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Jianming Zhang
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Zhonglin Zhu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Zhilong Yu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Qi Li
- Department of Medical Oncology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhengjun Qiu
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China
| | - Chen Huang
- Department of General Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Hai Ning Road, Hongkou District, Shanghai, 200080, China.
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21
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Sodium background currents in endocrine/neuroendocrine cells: Towards unraveling channel identity and contribution in hormone secretion. Front Neuroendocrinol 2021; 63:100947. [PMID: 34592201 DOI: 10.1016/j.yfrne.2021.100947] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/03/2021] [Accepted: 09/23/2021] [Indexed: 02/04/2023]
Abstract
In endocrine/neuroendocrine tissues, excitability of secretory cells is patterned by the repertoire of ion channels and there is clear evidence that extracellular sodium (Na+) ions contribute to hormone secretion. While voltage-gated channels involved in action potential generation are well-described, the background 'leak' channels operating near the resting membrane potential are much less known, and in particular the channels supporting a background entry of Na+ ions. These background Na+ currents (called here 'INab') have the ability to modulate the resting membrane potential and subsequently affect action potential firing. Here we compile and analyze the data collected from three endocrine/neuroendocrine tissues: the anterior pituitary gland, the adrenal medulla and the endocrine pancreas. We also model how INab can be functionally involved in cellular excitability. Finally, towards deciphering the physiological role of INab in endocrine/neuroendocrine cells, its implication in hormone release is also discussed.
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22
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Li J, Chen Y, Liu J, Zhang D, Liang P, Lu P, Shen J, Miao C, Zuo Y, Zhou C. Elevated Expression and Activity of Sodium Leak Channel Contributes to Neuronal Sensitization of Inflammatory Pain in Rats. Front Mol Neurosci 2021; 14:723395. [PMID: 34512260 PMCID: PMC8430348 DOI: 10.3389/fnmol.2021.723395] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/02/2021] [Indexed: 02/05/2023] Open
Abstract
Inflammatory pain encompasses many clinical symptoms, and there is no satisfactory therapeutic target. Neuronal hyperexcitability and/or sensitization of the primary nociceptive neurons in the dorsal root ganglion (DRG) and spinal dorsal horn are critical to the development and maintenance of inflammatory pain. The sodium leak channel (NALCN), a non-selective cation channel, mediates the background Na+ leak conductance and controls neuronal excitability. It is unknown whether abnormal activity of NALCN mediates the pathological process of inflammatory pain. Complete Freund’s adjuvant (CFA) was injected into the left footpad of rats to induce inflammatory pain. The thresholds of mechanical and thermal sensation and spontaneous pain behaviors were assessed. The expression of NALCN in DRG and spinal dorsal cord was measured. NALCN currents and the contribution of NALCN to neuronal excitability in the DRG and spinal dorsal cord were recorded using whole-cell patch-clamping recording. NALCN was abundantly expressed in neurons of the DRG and spinal dorsal cord. In acutely isolated DRG neurons and spinal cord slices from rats with CFA-induced inflammatory pain, NALCN currents and neuronal excitability were increased. Subsequently, intrathecal and sciatic nerve injection of NALCN-small interfering RNA (siRNA) decreased NALCN mRNA and reverted NALCN currents to normal levels, and then reduced CFA-induced neuronal excitability and alleviated pain symptoms. Furthermore, pain-related symptoms were significantly prevented by the NALCN-shRNA-mediated NALCN knockdown in DRG and spinal cord. Therefore, increased expression and activity of NALCN contributed to neuronal sensitization in CFA-induced inflammatory pain. NALCN may be a novel molecular target for the control of inflammatory pain.
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Affiliation(s)
- Jia Li
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, Xi'an Jiaotong University-Affiliated Honghui Hospital, Xi'an, China
| | - Yali Chen
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Peilin Lu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jiefei Shen
- Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases and Department of Prosthodontics, West China Stomatology Hospital of Sichuan University, Chengdu, China
| | - Changhong Miao
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Cheng Zhou
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
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23
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Kropp PA, Bauer R, Zafra I, Graham C, Golden A. Caenorhabditis elegans for rare disease modeling and drug discovery: strategies and strengths. Dis Model Mech 2021; 14:dmm049010. [PMID: 34370008 PMCID: PMC8380043 DOI: 10.1242/dmm.049010] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although nearly 10% of Americans suffer from a rare disease, clinical progress in individual rare diseases is severely compromised by lack of attention and research resources compared to common diseases. It is thus imperative to investigate these diseases at their most basic level to build a foundation and provide the opportunity for understanding their mechanisms and phenotypes, as well as potential treatments. One strategy for effectively and efficiently studying rare diseases is using genetically tractable organisms to model the disease and learn about the essential cellular processes affected. Beyond investigating dysfunctional cellular processes, modeling rare diseases in simple organisms presents the opportunity to screen for pharmacological or genetic factors capable of ameliorating disease phenotypes. Among the small model organisms that excel in rare disease modeling is the nematode Caenorhabditis elegans. With a staggering breadth of research tools, C. elegans provides an ideal system in which to study human disease. Molecular and cellular processes can be easily elucidated, assayed and altered in ways that can be directly translated to humans. When paired with other model organisms and collaborative efforts with clinicians, the power of these C. elegans studies cannot be overstated. This Review highlights studies that have used C. elegans in diverse ways to understand rare diseases and aid in the development of treatments. With continuing and advancing technologies, the capabilities of this small round worm will continue to yield meaningful and clinically relevant information for human health.
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Affiliation(s)
| | | | | | | | - Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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24
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Impheng H, Lemmers C, Bouasse M, Legros C, Pakaprot N, Guérineau NC, Lory P, Monteil A. The sodium leak channel NALCN regulates cell excitability of pituitary endocrine cells. FASEB J 2021; 35:e21400. [PMID: 33793981 DOI: 10.1096/fj.202000841rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 11/11/2022]
Abstract
Anterior pituitary endocrine cells that release hormones such as growth hormone and prolactin are excitable and fire action potentials. In these cells, several studies previously showed that extracellular sodium (Na+ ) removal resulted in a negative shift of the resting membrane potential (RMP) and a subsequent inhibition of the spontaneous firing of action potentials, suggesting the contribution of a Na+ background conductance. Here, we show that the Na+ leak channel NALCN conducts a Ca2+ - Gd3+ -sensitive and TTX-resistant Na+ background conductance in the GH3 cell line, a cell model of pituitary endocrine cells. NALCN knockdown hyperpolarized the RMP, altered GH3 cell electrical properties and inhibited prolactin secretion. Conversely, the overexpression of NALCN depolarized the RMP, also reshaping the electrical properties of GH3 cells. Overall, our results indicate that NALCN is functional in GH3 cells and involved in endocrine cell excitability as well as in hormone secretion. Indeed, the GH3 cell line suitably models native pituitary cells that display a similar Na+ background conductance and appears as a proper cellular model to study the role of NALCN in cellular excitability.
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Affiliation(s)
- Hathaichanok Impheng
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Céline Lemmers
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,PVM, BCM, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Malik Bouasse
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Christian Legros
- MITOVASC Institute, UMR CNRS 6015 - UMR INSERM U1083, Université d'Angers, Angers, France
| | - Narawut Pakaprot
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Arnaud Monteil
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France.,PVM, BCM, Université de Montpellier, CNRS, INSERM, Montpellier, France
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25
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The gating pore blocker 1-(2,4-xylyl)guanidinium selectively inhibits pacemaking of midbrain dopaminergic neurons. Neuropharmacology 2021; 197:108722. [PMID: 34273387 DOI: 10.1016/j.neuropharm.2021.108722] [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: 03/27/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/22/2022]
Abstract
Although several ionic mechanisms are known to control rate and regularity of the slow pacemaker in dopamine (DA) neurons, the core mechanism of pacing is controversial. Here we tested the hypothesis that pacemaking of SNc DA neurons is enabled by an unconventional conductance. We found that 1-(2,4-xylyl)guanidinium (XG), an established blocker of gating pore currents, selectively inhibits pacemaking of DA neurons. The compound inhibited all slow pacemaking DA neurons that were tested, both in the substantia nigra pars compacta, and in the ventral tegmental area. Interestingly, bursting behavior was not affected by XG. Furthermore, the drug did not affect fast pacemaking of GABAergic neurons from substantia nigra pars reticulata neurons or slow pacemaking of noradrenergic neurons. In DA neurons, current-clamp analysis revealed that XG did not appear to affect ion channels involved in the action potential. Its inhibitory effect persisted during blockade of all ion channels previously suggested to contribute to pacemaking. RNA sequencing and voltage-clamp recordings yielded no evidence for a gating pore current to underlie the conductance. However, we could isolate a small subthreshold XG-sensitive current, which was carried by both Na+ and Cl- ions. Although the molecular target of XG remains to be defined, these observations represent a step towards understanding pacemaking in DA neurons.
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26
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Wu Y, Zhang D, Liu J, Yang Y, Ou M, Liu B, Zhou C. Sodium Leak Channel in the Nucleus Accumbens Modulates Ethanol-Induced Acute Stimulant Responses and Locomotor Sensitization in Mice: A Brief Research Report. Front Neurosci 2021; 15:687470. [PMID: 34335164 PMCID: PMC8316816 DOI: 10.3389/fnins.2021.687470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/18/2021] [Indexed: 02/05/2023] Open
Abstract
Ethanol can induce acute stimulant responses in animals and human beings. Moreover, repeated exposure to ethanol may produce increased sensitivity to its acute locomotor stimulant actions, a process referred to as locomotor sensitization. The molecular mechanism of the development of acute stimulant responses and locomotor sensitization by ethanol is not fully understood. Sodium leak channel (NALCN) is widely expressed in central nervous system and controls the basal excitability of neurons. The present study aims to determine whether NALCN is implicated in the ethanol-induced acute responses and locomotor sensitization in mice. Here, our results showed that ethanol caused acute stimulant responses in DBA/2 mice. Locomotor sensitization was successfully induced following the sensitization procedure. Accordingly, the expression levels of NALCN mRNA and protein in the nucleus accumbens (NAc) were markedly increased in the sensitization mice compared to the control mice. Knockdown the expression levels of NALCN in the NAc alleviated both the ethanol-induced acute responses and locomotor sensitization. Our findings indicate that upregulation of NALCN expression in the NAc contributes to the ethanol-induced acute stimulant responses and locomotor sensitization in DBA/2 mice.
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Affiliation(s)
- Yujie Wu
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Donghang Zhang
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Liu
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yaoxin Yang
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Mengchan Ou
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Bin Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
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27
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Na + leak-current channel (NALCN) at the junction of motor and neuropsychiatric symptoms in Parkinson's disease. J Neural Transm (Vienna) 2021; 128:749-762. [PMID: 33961117 DOI: 10.1007/s00702-021-02348-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/30/2021] [Indexed: 12/27/2022]
Abstract
Parkinson's disease (PD) is a debilitating movement disorder often accompanied by neuropsychiatric symptoms that stem from the loss of dopaminergic function in the basal ganglia and altered neurotransmission more generally. Akinesia, postural instability, tremors and frozen gait constitute the major motor disturbances, whereas neuropsychiatric symptoms include altered circadian rhythms, disordered sleep, depression, psychosis and cognitive impairment. Evidence is emerging that the motor and neuropsychiatric symptoms may share etiologic factors. Calcium/ion channels (CACNA1C, NALCN), synaptic proteins (SYNJ1) and neuronal RNA-binding proteins (RBFOX1) are among the risk genes that are common to PD and various psychiatric disorders. The Na+ leak-current channel (NALCN) is the focus of this review because it has been implicated in dystonia, regulation of movement, cognitive impairment, sleep and circadian rhythms. It regulates the resting membrane potential in neurons, mediates pace-making activity, participates in synaptic vesicle recycling and is functionally co-localized to the endoplasmic reticulum (ER)-several of the major processes adversely affected in PD. Here, we summarize the literature on mechanisms and pathways that connect the motor and neuropsychiatric symptoms of PD with a focus on recurring relationships to the NALCN. It is hoped that the various connections outlined here will stimulate further discussion, suggest additional areas for exploration and ultimately inspire novel treatment strategies.
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28
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Zhang D, Zhao W, Liu J, Ou M, Liang P, Li J, Chen Y, Liao D, Bai S, Shen J, Chen X, Huang H, Zhou C. Sodium leak channel contributes to neuronal sensitization in neuropathic pain. Prog Neurobiol 2021; 202:102041. [PMID: 33766679 DOI: 10.1016/j.pneurobio.2021.102041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 02/08/2021] [Accepted: 03/18/2021] [Indexed: 02/08/2023]
Abstract
Neuropathic pain affects up to 10 % of the total population and no specific target is ideal for therapeutic need. The sodium leak channel (NALCN), a non-selective cation channel, mediates the background Na+ leak conductance and controls neuronal excitability and rhythmic behaviors. Here, we show that increases of NALCN expression and function in dorsal root ganglion (DRG) and dorsal spinal cord contribute to chronic constriction injury (CCI)-induced neuropathic pain in rodents. NALCN current and neuronal excitability in acutely isolated DRG neurons and spinal cord slices of rats were increased after CCI which were decreased to normal levels by NALCN-siRNA. Accordingly, pain-related symptoms were significantly alleviated by NALCN-siRNA-mediated NALCN knockdown and completely prevented by NALCN-shRNA-mediated NALCN knockdown in rats or by conditional NALCN knockout in mice. Our results indicate that increases in NALCN expression and function contribute to CCI-induced neuronal sensitization; therefore, NALCN may be a novel molecular target for control of neuropathic pain.
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Affiliation(s)
- Donghang Zhang
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Wenling Zhao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jin Liu
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Mengchan Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jia Li
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Yali Chen
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Daqing Liao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Siqi Bai
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jiefei Shen
- Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases and Department of Prosthodontics, West China Stomatology Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Xiangdong Chen
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei, China
| | - Han Huang
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology & Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital of Sichuan University, Chengdu 610041, Sichuan, China.
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China.
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29
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Milman A, Ventéo S, Bossu JL, Fontanaud P, Monteil A, Lory P, Guérineau NC. A sodium background conductance controls the spiking pattern of mouse adrenal chromaffin cells in situ. J Physiol 2021; 599:1855-1883. [PMID: 33450050 PMCID: PMC7986707 DOI: 10.1113/jp281044] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Mouse chromaffin cells in acute adrenal slices exhibit two distinct spiking patterns, a repetitive mode and a bursting mode. A sodium background conductance operates at rest as demonstrated by the membrane hyperpolarization evoked by a low Na+ -containing extracellular saline. This sodium background current is insensitive to TTX, is not blocked by Cs+ ions and displays a linear I-V relationship at potentials close to chromaffin cell resting potential. Its properties are reminiscent of those of the sodium leak channel NALCN. In the adrenal gland, Nalcn mRNA is selectively expressed in chromaffin cells. The study fosters our understanding of how the spiking pattern of chromaffin cells is regulated and adds a sodium background conductance to the list of players involved in the stimulus-secretion coupling of the adrenomedullary tissue. ABSTRACT Chromaffin cells (CCs) are the master neuroendocrine units for the secretory function of the adrenal medulla and a finely-tuned regulation of their electrical activity is required for appropriate catecholamine secretion in response to the organismal demand. Here, we aim at deciphering how the spiking pattern of mouse CCs is regulated by the ion conductances operating near the resting membrane potential (RMP). At RMP, mouse CCs display a composite firing pattern, alternating between active periods composed of action potentials spiking with a regular or a bursting mode, and silent periods. RMP is sensitive to changes in extracellular sodium concentration, and a low Na+ -containing saline hyperpolarizes the membrane, regardless of the discharge pattern. This RMP drive reflects the contribution of a depolarizing conductance, which is (i) not blocked by tetrodotoxin or caesium, (ii) displays a linear I-V relationship between -110 and -40 mV, and (iii) is carried by cations with a conductance sequence gNa > gK > gCs . These biophysical attributes, together with the expression of the sodium-leak channel Nalcn transcript in CCs, state credible the contribution of NALCN. This inaugural report opens new research routes in the field of CC stimulus-secretion coupling, and extends the inventory of tissues in which NALCN is expressed to neuroendocrine glands.
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Affiliation(s)
- Alexandre Milman
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | | | - Jean-Louis Bossu
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212, Strasbourg, France
| | - Pierre Fontanaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
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30
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Dong N, Bandura J, Zhang Z, Wang Y, Labadie K, Noel B, Davison A, Koene JM, Sun HS, Coutellec MA, Feng ZP. Ion channel profiling of the Lymnaea stagnalis ganglia via transcriptome analysis. BMC Genomics 2021; 22:18. [PMID: 33407100 PMCID: PMC7789530 DOI: 10.1186/s12864-020-07287-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/28/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The pond snail Lymnaea stagnalis (L. stagnalis) has been widely used as a model organism in neurobiology, ecotoxicology, and parasitology due to the relative simplicity of its central nervous system (CNS). However, its usefulness is restricted by a limited availability of transcriptome data. While sequence information for the L. stagnalis CNS transcripts has been obtained from EST libraries and a de novo RNA-seq assembly, the quality of these assemblies is limited by a combination of low coverage of EST libraries, the fragmented nature of de novo assemblies, and lack of reference genome. RESULTS In this study, taking advantage of the recent availability of a preliminary L. stagnalis genome, we generated an RNA-seq library from the adult L. stagnalis CNS, using a combination of genome-guided and de novo assembly programs to identify 17,832 protein-coding L. stagnalis transcripts. We combined our library with existing resources to produce a transcript set with greater sequence length, completeness, and diversity than previously available ones. Using our assembly and functional domain analysis, we profiled L. stagnalis CNS transcripts encoding ion channels and ionotropic receptors, which are key proteins for CNS function, and compared their sequences to other vertebrate and invertebrate model organisms. Interestingly, L. stagnalis transcripts encoding numerous putative Ca2+ channels showed the most sequence similarity to those of Mus musculus, Danio rerio, Xenopus tropicalis, Drosophila melanogaster, and Caenorhabditis elegans, suggesting that many calcium channel-related signaling pathways may be evolutionarily conserved. CONCLUSIONS Our study provides the most thorough characterization to date of the L. stagnalis transcriptome and provides insights into differences between vertebrates and invertebrates in CNS transcript diversity, according to function and protein class. Furthermore, this study provides a complete characterization of the ion channels of Lymnaea stagnalis, opening new avenues for future research on fundamental neurobiological processes in this model system.
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Affiliation(s)
- Nancy Dong
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Julia Bandura
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Zhaolei Zhang
- Donnelly Centre for Cellular and Biomolecular Research and Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Yan Wang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Karine Labadie
- Genoscope, Institut de biologie François Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, BP5706, 91057, Evry, France
| | - Benjamin Noel
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, University of Evry, Université Paris-Saclay, 91057, Evry, France
| | - Angus Davison
- School of Life Sciences, University of Nottingham, University Park, Nottingham, UK, NG7 2RD, UK
| | - Joris M Koene
- Department of Ecological Science, Faculty of Science, Vrije Universiteit, Amsterdam, The Netherlands
| | - Hong-Shuo Sun
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | | | - Zhong-Ping Feng
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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Kang Y, Wu JX, Chen L. Structure of voltage-modulated sodium-selective NALCN-FAM155A channel complex. Nat Commun 2020; 11:6199. [PMID: 33273469 PMCID: PMC7712781 DOI: 10.1038/s41467-020-20002-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
Resting membrane potential determines the excitability of the cell and is essential for the cellular electrical activities. The NALCN channel mediates sodium leak currents, which positively adjust resting membrane potential towards depolarization. The NALCN channel is involved in several neurological processes and has been implicated in a spectrum of neurodevelopmental diseases. Here, we report the cryo-EM structure of rat NALCN and mouse FAM155A complex to 2.7 Å resolution. The structure reveals detailed interactions between NALCN and the extracellular cysteine-rich domain of FAM155A. We find that the non-canonical architecture of NALCN selectivity filter dictates its sodium selectivity and calcium block, and that the asymmetric arrangement of two functional voltage sensors confers the modulation by membrane potential. Moreover, mutations associated with human diseases map to the domain-domain interfaces or the pore domain of NALCN, intuitively suggesting their pathological mechanisms. The NALCN channel mediates sodium leak currents, which in turn adjusts resting membrane potential and neuronal excitability. Here the authors describe a cryo-EM structure of mammalian NALCN-FAM155A channel complex, showing how selectivity filter contributes to sodium permeation and calcium block and how the voltage sensors contribute to current modulation.
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Affiliation(s)
- Yunlu Kang
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China. .,Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.
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Xie J, Ke M, Xu L, Lin S, Huang J, Zhang J, Yang F, Wu J, Yan Z. Structure of the human sodium leak channel NALCN in complex with FAM155A. Nat Commun 2020; 11:5831. [PMID: 33203861 PMCID: PMC7672056 DOI: 10.1038/s41467-020-19667-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/26/2020] [Indexed: 01/18/2023] Open
Abstract
NALCN, a sodium leak channel expressed mainly in the central nervous system, is responsible for the resting Na+ permeability that controls neuronal excitability. Dysfunctions of the NALCN channelosome, NALCN with several auxiliary subunits, are associated with a variety of human diseases. Here, we report the cryo-EM structure of human NALCN in complex with FAM155A at an overall resolution of 3.1 angstroms. FAM155A forms extensive interactions with the extracellular loops of NALCN that may help stabilize NALCN in the membrane. A Na+ ion-binding site, reminiscent of a Ca2+ binding site in Cav channels, is identified in the unique EEKE selectivity filter. Despite its 'leaky' nature, the channel is closed and the intracellular gate is sealed by S6I, II-III linker and III-IV linker. Our study establishes the molecular basis of Na+ permeation and voltage sensitivity, and provides important clues to the mechanistic understanding of NALCN regulation and NALCN channelosome-related diseases.
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Affiliation(s)
- Jiongfang Xie
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China
| | - Meng Ke
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China
| | - Lizhen Xu
- Department of Biophysics and Kidney Disease Center, First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China
| | - Shiyi Lin
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China
| | - Jin Huang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China
| | - Jiabei Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China
| | - Fan Yang
- Department of Biophysics and Kidney Disease Center, First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China.
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China.
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China.
| | - Zhen Yan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 310024, Hangzhou, Zhejiang, China.
- Westlake Laboratory of Life Sciences and Biomedicine, 310024, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, 310024, Hangzhou, Zhejiang, China.
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Structure of the human sodium leak channel NALCN. Nature 2020; 587:313-318. [DOI: 10.1038/s41586-020-2570-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/02/2020] [Indexed: 01/17/2023]
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Hayashi T, Oishi K, Kimura M, Iida K, Iida H. Highly conserved extracellular residues mediate interactions between pore-forming and regulatory subunits of the yeast Ca 2+ channel related to the animal VGCC/NALCN family. J Biol Chem 2020; 295:13008-13022. [PMID: 32690610 PMCID: PMC7489899 DOI: 10.1074/jbc.ra120.014378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/14/2020] [Indexed: 12/23/2022] Open
Abstract
Yeasts and fungi generate Ca2+ signals in response to environmental stresses through Ca2+ channels essentially composed of Cch1 and Mid1. Cch1 is homologous to the pore-forming α1 subunit of animal voltage-gated Ca2+ channels (VGCCs) and sodium leak channels nonselective (NALCNs), whereas Mid1 is a membrane-associated protein similar to the regulatory α2/δ subunit of VGCCs and the regulatory subunit of NALCNs. Although the physiological roles of Cch1/Mid1 channels are known, their molecular regulation remains elusive, including subunit interactions regulating channel functionality. Herein, we identify amino acid residues involved in interactions between the pore-forming Cch1 subunit and the essential regulatory Mid1 subunit of Saccharomyces cerevisiae. In vitro mutagenesis followed by functional assays and co-immunoprecipitation experiments reveal that three residues present in a specific extracellular loop in the repeat III region of Cch1 are required for interaction with Mid1, and that one essential Mid1 residue is required for interaction with Cch1. Importantly, these residues are necessary for Ca2+ channel activity and are highly conserved in fungal and animal counterparts. We discuss that this unique subunit interaction-based regulatory mechanism for Cch1 differs from that of VGCCs/NALCNs.
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Affiliation(s)
- Takuto Hayashi
- Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo, Japan
| | - Keita Oishi
- Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo, Japan
| | - Midori Kimura
- Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo, Japan
| | - Kazuko Iida
- Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo, Japan; Laboratory of Biomembrane, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, Japan
| | - Hidetoshi Iida
- Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo, Japan.
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Wie J, Bharthur A, Wolfgang M, Narayanan V, Ramsey K, Aranda K, Zhang Q, Zhou Y, Ren D. Intellectual disability-associated UNC80 mutations reveal inter-subunit interaction and dendritic function of the NALCN channel complex. Nat Commun 2020; 11:3351. [PMID: 32620897 PMCID: PMC7335163 DOI: 10.1038/s41467-020-17105-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 06/11/2020] [Indexed: 01/08/2023] Open
Abstract
The sodium-leak channel NALCN forms a subthreshold sodium conductance that controls the resting membrane potentials of neurons. The auxiliary subunits of the channel and their functions in mammals are largely unknown. In this study, we demonstrate that two large proteins UNC80 and UNC79 are subunits of the NALCN complex. UNC80 knockout mice are neonatal lethal. The C-terminus of UNC80 contains a domain that interacts with UNC79 and overcomes a soma-retention signal to achieve dendritic localization. UNC80 lacking this domain, as found in human patients, still supports whole-cell NALCN currents but lacks dendritic localization. Our results establish the subunit composition of the NALCN complex, uncover the inter-subunit interaction domains, reveal the functional significance of regulation of dendritic membrane potential by the sodium-leak channel complex, and provide evidence supporting that genetic variations found in individuals with intellectual disability are the causes for the phenotype observed in patients.
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Affiliation(s)
- Jinhong Wie
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Apoorva Bharthur
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Morgan Wolfgang
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Kimberly Aranda
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Qi Zhang
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yandong Zhou
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Chua HC, Wulf M, Weidling C, Rasmussen LP, Pless SA. The NALCN channel complex is voltage sensitive and directly modulated by extracellular calcium. SCIENCE ADVANCES 2020; 6:eaaz3154. [PMID: 32494638 PMCID: PMC7182417 DOI: 10.1126/sciadv.aaz3154] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/03/2020] [Indexed: 05/24/2023]
Abstract
The sodium leak channel (NALCN) is essential for survival in mammals: NALCN mutations are life-threatening in humans and knockout is lethal in mice. However, the basic functional and pharmacological properties of NALCN have remained elusive. Here, we found that robust function of NALCN in heterologous systems requires co-expression of UNC79, UNC80, and FAM155A. The resulting NALCN channel complex is constitutively active and conducts monovalent cations but is blocked by physiological concentrations of extracellular divalent cations. Our data support the notion that NALCN is directly responsible for the increased excitability observed in a variety of neurons in reduced extracellular Ca2+. Despite the smaller number of voltage-sensing residues in NALCN, the constitutive activity is modulated by voltage, suggesting that voltage-sensing domains can give rise to a broader range of gating phenotypes than previously anticipated. Our work points toward formerly unknown contributions of NALCN to neuronal excitability and opens avenues for pharmacological targeting.
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The NALCN Channel Regulator UNC-80 Functions in a Subset of Interneurons To Regulate Caenorhabditis elegans Reversal Behavior. G3-GENES GENOMES GENETICS 2020; 10:199-210. [PMID: 31690562 PMCID: PMC6945035 DOI: 10.1534/g3.119.400692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
NALCN (Na+leak channel, non-selective) is a conserved, voltage-insensitive cation channel that regulates resting membrane potential and neuronal excitability. UNC79 and UNC80 are key regulators of the channel function. However, the behavioral effects of the channel complex are not entirely clear and the neurons in which the channel functions remain to be identified. In a forward genetic screen for C. elegans mutants with defective avoidance response to the plant hormone methyl salicylate (MeSa), we isolated multiple loss-of-function mutations in unc-80 and unc-79. C. elegans NALCN mutants exhibited similarly defective MeSa avoidance. Interestingly, NALCN, unc-80 and unc-79 mutants all showed wild type-like responses to other attractive or repelling odorants, suggesting that NALCN does not broadly affect odor detection or related forward and reversal behaviors. To understand in which neurons the channel functions, we determined the identities of a subset of unc-80-expressing neurons. We found that unc-79 and unc-80 are expressed and function in overlapping neurons, which verified previous assumptions. Neuron-specific transgene rescue and knockdown experiments suggest that the command interneurons AVA and AVE and the anterior guidepost neuron AVG can play a sufficient role in mediating unc-80 regulation of the MeSa avoidance. Though primarily based on genetic analyses, our results further imply that MeSa might activate NALCN by direct or indirect actions. Altogether, we provide an initial look into the key neurons in which the NALCN channel complex functions and identify a novel function of the channel in regulating C. elegans reversal behavior through command interneurons.
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FUNATO H. Forward genetic approach for behavioral neuroscience using animal models. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:10-31. [PMID: 31932526 PMCID: PMC6974404 DOI: 10.2183/pjab.96.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
Forward genetics is a powerful approach to understand the molecular basis of animal behaviors. Fruit flies were the first animal to which this genetic approach was applied systematically and have provided major discoveries on behaviors including sexual, learning, circadian, and sleep-like behaviors. The development of different classes of model organism such as nematodes, zebrafish, and mice has enabled genetic research to be conducted using more-suitable organisms. The unprecedented success of forward genetic approaches was the identification of the transcription-translation negative feedback loop composed of clock genes as a fundamental and conserved mechanism of circadian rhythm. This approach has now expanded to sleep/wakefulness in mice. A conventional strategy such as dominant and recessive screenings can be modified with advances in DNA sequencing and genome editing technologies.
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Affiliation(s)
- Hiromasa FUNATO
- Department of Anatomy, Faculty of Medicine, Toho University, Tokyo, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Ibaraki, Japan
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Yue X, Sheng Y, Kang L, Xiao R. Distinct functions of TMC channels: a comparative overview. Cell Mol Life Sci 2019; 76:4221-4232. [PMID: 31584127 PMCID: PMC11105308 DOI: 10.1007/s00018-019-03214-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/18/2022]
Abstract
In the past two decades, transmembrane channel-like (TMC) proteins have attracted a significant amount of research interest, because mutations of Tmc1 lead to hereditary deafness. As evolutionarily conserved membrane proteins, TMC proteins are widely involved in diverse sensorimotor functions of many species, such as hearing, chemosensation, egg laying, and food texture detection. Interestingly, recent structural and physiological studies suggest that TMC channels may share a similar membrane topology with the Ca2+-activated Cl- channel TMEM16 and the mechanically activated OSCA1.2/TMEM63 channel. Namely, these channels form dimers and each subunit consists of ten transmembrane segments. Despite this important structural insight, a key question remains: what is the gating mechanism of TMC channels? The major technical hurdle to answer this question is that the reconstitution of TMC proteins as functional ion channels has been challenging in mammalian heterologous systems. Since TMC channels are conserved across taxa, genetic studies of TMC channels in model organisms such as C. elegans, Drosophila, and zebrafish may provide us critical information on the physiological function and regulation of TMCs. Here, we present a comparative overview on the diverse functions of TMC channels in different species.
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Affiliation(s)
- Xiaomin Yue
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sheng
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
| | - Lijun Kang
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.
| | - Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA.
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL, USA.
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
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Bouasse M, Impheng H, Servant Z, Lory P, Monteil A. Functional expression of CLIFAHDD and IHPRF pathogenic variants of the NALCN channel in neuronal cells reveals both gain- and loss-of-function properties. Sci Rep 2019; 9:11791. [PMID: 31409833 PMCID: PMC6692409 DOI: 10.1038/s41598-019-48071-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/29/2019] [Indexed: 12/24/2022] Open
Abstract
The excitability of neurons is tightly dependent on their ion channel repertoire. Among these channels, the leak sodium channel NALCN plays a crucial role in the maintenance of the resting membrane potential. Importantly, NALCN mutations lead to complex neurodevelopmental syndromes, including infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of limbs and face, hypotonia and developmental delay (CLIFAHDD), which are recessively and dominantly inherited, respectively. Unfortunately, the biophysical properties of NALCN are still largely unknown to date, as well as the functional consequences of both IHPRF and CLIFAHDD mutations on NALCN current. Here we have set-up the heterologous expression of NALCN in the neuronal cell line NG108-15 to investigate the electrophysiological properties of NALCN carrying representative IHPRF and CLIFAHDD mutations. Several original properties of the wild-type (wt) NALCN current were retrieved: mainly carried by external Na+, blocked by Gd3+, insensitive to TTX and potentiated by low external Ca2+ concentration. However, we found that this current displays a time-dependent inactivation in the −80/−40 mV range of membrane potential, and a non linear current-voltage relationship indicative of voltage sensitivity. Importantly, no detectable current was recorded with the IHPRF missense mutation p.Trp1287Leu (W1287L), while the CLIFAHDD mutants, p.Leu509Ser (L509S) and p.Tyr578Ser (Y578S), showed higher current densities and slower inactivation, compared to wt NALCN current. This study reveals that heterologous expression of NALCN channel can be achieved in the neuronal cell line NG108-15 to study the electrophysiological properties of wt and mutants. From our results, we conclude that IHPRF and CLIFAHDD missense mutations are loss- and gain-of-function variants, respectively.
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Affiliation(s)
- Malik Bouasse
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Hathaichanok Impheng
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Zoe Servant
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Arnaud Monteil
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France.
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Gap Junctions and NCA Cation Channels Are Critical for Developmentally Timed Sleep and Arousal in Caenorhabditis elegans. Genetics 2018; 210:1369-1381. [PMID: 30323068 DOI: 10.1534/genetics.118.301551] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/10/2018] [Indexed: 12/16/2022] Open
Abstract
An essential characteristic of sleep is heightened arousal threshold, with decreased behavioral response to external stimuli. The molecular and cellular mechanisms underlying arousal threshold changes during sleep are not fully understood. We report that loss of UNC-7 or UNC-9 innexin function dramatically reduced sleep and decreased arousal threshold during developmentally timed sleep in Caenorhabditis elegans UNC-7 function was required in premotor interneurons and UNC-9 function was required in motor neurons in this paradigm. Simultaneous transient overexpression of UNC-7 and UNC-9 was sufficient to induce anachronistic sleep in adult animals. Moreover, loss of UNC-7 or UNC-9 suppressed the increased sleep of EGL-4 gain-of-function animals, which have increased cyclic-GMP-dependent protein kinase activity. These results suggest C. elegans gap junctions may act downstream of previously identified sleep regulators. In other paradigms, the NCA cation channels act upstream of gap junctions. Consistent with this, diminished NCA channel activity in C. elegans robustly increased arousal thresholds during sleep bouts in L4-to-adult developmentally timed sleep. Total time in sleep bouts was only modestly increased in animals lacking NCA channel auxiliary subunit UNC-79, whereas increased channel activity dramatically decreased sleep. Loss of EGL-4 or innexin proteins suppressed UNC-79 loss-of-function sleep and arousal defects. In Drosophila, the ion channel narrow abdomen, an ortholog of the C. elegans NCA channels, drive the pigment dispersing factor (PDF) neuropeptide release, regulating circadian behavior. However, in C. elegans, we found that loss of the PDF receptor PDFR-1 did not suppress gain-of-function sleep defects, suggesting an alternative downstream pathway. This study emphasizes the conservation and importance of neuronal activity modulation during sleep, and unequivocally demonstrates that gap junction function is critical for normal sleep.
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Wen Q, Gao S, Zhen M. Caenorhabditis elegans excitatory ventral cord motor neurons derive rhythm for body undulation. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0370. [PMID: 30201835 DOI: 10.1098/rstb.2017.0370] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2018] [Indexed: 12/25/2022] Open
Abstract
The intrinsic oscillatory activity of central pattern generators underlies motor rhythm. We review and discuss recent findings that address the origin of Caenorhabditis elegans motor rhythm. These studies propose that the A- and mid-body B-class excitatory motor neurons at the ventral cord function as non-bursting intrinsic oscillators to underlie body undulation during reversal and forward movements, respectively. Proprioception entrains their intrinsic activities, allows phase-coupling between members of the same class motor neurons, and thereby facilitates directional propagation of undulations. Distinct pools of premotor interneurons project along the ventral nerve cord to innervate all members of the A- and B-class motor neurons, modulating their oscillations, as well as promoting their bi-directional coupling. The two motor sub-circuits, which consist of oscillators and descending inputs with distinct properties, form the structural base of dynamic rhythmicity and flexible partition of the forward and backward motor states. These results contribute to a continuous effort to establish a mechanistic and dynamic model of the C. elegans sensorimotor system. C. elegans exhibits rich sensorimotor functions despite a small neuron number. These findings implicate a circuit-level functional compression. By integrating the role of rhythm generation and proprioception into motor neurons, and the role of descending regulation of oscillators into premotor interneurons, this numerically simple nervous system can achieve a circuit infrastructure analogous to that of anatomically complex systems. C. elegans has manifested itself as a compact model to search for general principles of sensorimotor behaviours.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.
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Affiliation(s)
- Quan Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, People's Republic of China .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Mei Zhen
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital; Department of Molecular Genetics, Department of Physiology, University of Toronto, Toronto, Ontario M5G 1XS, Canada
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Yue X, Zhao J, Li X, Fan Y, Duan D, Zhang X, Zou W, Sheng Y, Zhang T, Yang Q, Luo J, Duan S, Xiao R, Kang L. TMC Proteins Modulate Egg Laying and Membrane Excitability through a Background Leak Conductance in C. elegans. Neuron 2018; 97:571-585.e5. [PMID: 29395910 DOI: 10.1016/j.neuron.2017.12.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/24/2017] [Accepted: 12/26/2017] [Indexed: 12/13/2022]
Abstract
Membrane excitability is a fundamentally important feature for all excitable cells including both neurons and muscle cells. However, the background depolarizing conductances in excitable cells, especially in muscle cells, are not well characterized. Although mutations in transmembrane channel-like (TMC) proteins TMC1 and TMC2 cause deafness and vestibular defects in mammals, their precise action modes are elusive. Here, we discover that both TMC-1 and TMC-2 are required for normal egg laying in C. elegans. Mutations in these TMC proteins cause membrane hyperpolarization and disrupt the rhythmic calcium activities in both neurons and muscles involved in egg laying. Mechanistically, TMC proteins enhance membrane depolarization through background leak currents and ectopic expression of both C. elegans and mammalian TMC proteins results in membrane depolarization. Therefore, we have identified an unexpected role of TMC proteins in modulating membrane excitability. Our results may provide mechanistic insights into the functions of TMC proteins in hearing loss and other diseases.
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Affiliation(s)
- Xiaomin Yue
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Jian Zhao
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Li
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuedan Fan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Duo Duan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyan Zhang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjuan Zou
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sheng
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
| | - Ting Zhang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Yang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhong Luo
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA; Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
| | - Lijun Kang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China.
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Gao S, Guan SA, Fouad AD, Meng J, Kawano T, Huang YC, Li Y, Alcaire S, Hung W, Lu Y, Qi YB, Jin Y, Alkema M, Fang-Yen C, Zhen M. Excitatory motor neurons are local oscillators for backward locomotion. eLife 2018; 7:e29915. [PMID: 29360035 PMCID: PMC5780044 DOI: 10.7554/elife.29915] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/22/2017] [Indexed: 01/16/2023] Open
Abstract
Cell- or network-driven oscillators underlie motor rhythmicity. The identity of C. elegans oscillators remains unknown. Through cell ablation, electrophysiology, and calcium imaging, we show: (1) forward and backward locomotion is driven by different oscillators; (2) the cholinergic and excitatory A-class motor neurons exhibit intrinsic and oscillatory activity that is sufficient to drive backward locomotion in the absence of premotor interneurons; (3) the UNC-2 P/Q/N high-voltage-activated calcium current underlies A motor neuron's oscillation; (4) descending premotor interneurons AVA, via an evolutionarily conserved, mixed gap junction and chemical synapse configuration, exert state-dependent inhibition and potentiation of A motor neuron's intrinsic activity to regulate backward locomotion. Thus, motor neurons themselves derive rhythms, which are dually regulated by the descending interneurons to control the reversal motor state. These and previous findings exemplify compression: essential circuit properties are conserved but executed by fewer numbers and layers of neurons in a small locomotor network.
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Affiliation(s)
- Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Sihui Asuka Guan
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Anthony D Fouad
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
| | - Jun Meng
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Taizo Kawano
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Yung-Chi Huang
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Yi Li
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Salvador Alcaire
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Wesley Hung
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Yangning Lu
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Yingchuan Billy Qi
- Neurobiology Section, Division of Biological SciencesUniversity of CaliforniaSan DiegoUnited States
| | - Yishi Jin
- Neurobiology Section, Division of Biological SciencesUniversity of CaliforniaSan DiegoUnited States
| | - Mark Alkema
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Christopher Fang-Yen
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaUnited States
- Department of NeuroscienceUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
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Iida K, Teng J, Cho T, Yoshikawa-Kimura S, Iida H. Post-translational processing and membrane translocation of the yeast regulatory Mid1 subunit of the Cch1/VGCC/NALCN cation channel family. J Biol Chem 2017; 292:20570-20582. [PMID: 29042437 PMCID: PMC5733593 DOI: 10.1074/jbc.m117.810283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/20/2017] [Indexed: 12/24/2022] Open
Abstract
Saccharomyces cerevisiae Mid1 is composed of 548 amino acids and a regulatory subunit of Cch1, a member of the eukaryotic pore-forming, four-domain cation channel family. The amino acid sequence and voltage insensitivity of Cch1 are more similar to those of Na+ leak channel non-selective (NALCN) than to the α1 subunit of voltage-gated Ca2+ channels (VGCCs). Despite a lack in overall primary sequence similarity, Mid1 resembles in some aspects VGCC α2/δ regulatory subunits and NALCN-associated proteins. Unlike animal α2/δ subunits, Mid1 and NALCN-associated proteins are essential for the function of the pore-forming subunit. We herein investigated the processing and membrane translocation of Mid1. Mid1 was found to have a 20-amino-acid-long N-terminal signal peptide and appeared to be entirely localized extracellularly. A signal peptide-deleted Mid1 protein, Mid1ΔN23, was N-glycosylated and retained Ca2+ influx activity through Cch1. Moreover, an N-terminal truncation analysis revealed that even truncated Mid1 lacking 209 N-terminal amino acid residues was N-glycosylated and maintained Ca2+ influx activity. A 219-amino-acid-truncated Mid1 protein lost this activity but was still N-glycosylated. In the sec71Δ and sec72Δ single mutants defective in the post-translational protein transport into the endoplasmic reticulum (ER), Mid1ΔN23 could not mediate Ca2+ influx and did not undergo N-glycosylation, whereas wild-type Mid1 exhibited normal Ca2+ influx activity and N-glycosylation in these mutants. Therefore, the signal peptide-lacking Mid1ΔN23 protein may be translocated to the ER exclusively through the post-translational protein translocation, which typically requires an N-terminal signal peptide. Mid1 may provide a tool for studying mechanisms of protein translocation into the ER.
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Affiliation(s)
- Kazuko Iida
- From the Laboratory of Biomembrane, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo 156-8506, Japan and
| | - Jinfeng Teng
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Toshihiko Cho
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Sato Yoshikawa-Kimura
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Hidetoshi Iida
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
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Rakowski F, Karbowski J. Optimal synaptic signaling connectome for locomotory behavior in Caenorhabditis elegans: Design minimizing energy cost. PLoS Comput Biol 2017; 13:e1005834. [PMID: 29155814 PMCID: PMC5714387 DOI: 10.1371/journal.pcbi.1005834] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 12/04/2017] [Accepted: 10/19/2017] [Indexed: 11/18/2022] Open
Abstract
The detailed knowledge of C. elegans connectome for 3 decades has not contributed dramatically to our understanding of worm's behavior. One of main reasons for this situation has been the lack of data on the type of synaptic signaling between particular neurons in the worm's connectome. The aim of this study was to determine synaptic polarities for each connection in a small pre-motor circuit controlling locomotion. Even in this compact network of just 7 neurons the space of all possible patterns of connection types (excitation vs. inhibition) is huge. To deal effectively with this combinatorial problem we devised a novel and relatively fast technique based on genetic algorithms and large-scale parallel computations, which we combined with detailed neurophysiological modeling of interneuron dynamics and compared the theory to the available behavioral data. As a result of these massive computations, we found that the optimal connectivity pattern that matches the best locomotory data is the one in which all interneuron connections are inhibitory, even those terminating on motor neurons. This finding is consistent with recent experimental data on cholinergic signaling in C. elegans, and it suggests that the system controlling locomotion is designed to save metabolic energy. Moreover, this result provides a solid basis for a more realistic modeling of neural control in these worms, and our novel powerful computational technique can in principle be applied (possibly with some modifications) to other small-scale functional circuits in C. elegans.
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Affiliation(s)
- Franciszek Rakowski
- Interdisciplinary Centre for Mathematical and Computational Modeling, University of Warsaw, Warsaw, Poland
- Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Jan Karbowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
- Institute of Applied Mathematics and Mechanics, Department of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
- * E-mail:
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48
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Topalidou I, Cooper K, Pereira L, Ailion M. Dopamine negatively modulates the NCA ion channels in C. elegans. PLoS Genet 2017; 13:e1007032. [PMID: 28968387 PMCID: PMC5638609 DOI: 10.1371/journal.pgen.1007032] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 10/12/2017] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
The NALCN/NCA ion channel is a cation channel related to voltage-gated sodium and calcium channels. NALCN has been reported to be a sodium leak channel with a conserved role in establishing neuronal resting membrane potential, but its precise cellular role and regulation are unclear. The Caenorhabditis elegans orthologs of NALCN, NCA-1 and NCA-2, act in premotor interneurons to regulate motor circuit activity that sustains locomotion. Recently we found that NCA-1 and NCA-2 are activated by a signal transduction pathway acting downstream of the heterotrimeric G protein Gq and the small GTPase Rho. Through a forward genetic screen, here we identify the GPCR kinase GRK-2 as a new player affecting signaling through the Gq-Rho-NCA pathway. Using structure-function analysis, we find that the GPCR phosphorylation and membrane association domains of GRK-2 are required for its function. Genetic epistasis experiments suggest that GRK-2 acts on the D2-like dopamine receptor DOP-3 to inhibit Go signaling and positively modulate NCA-1 and NCA-2 activity. Through cell-specific rescuing experiments, we find that GRK-2 and DOP-3 act in premotor interneurons to modulate NCA channel function. Finally, we demonstrate that dopamine, through DOP-3, negatively regulates NCA activity. Thus, this study identifies a pathway by which dopamine modulates the activity of the NCA channels.
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Affiliation(s)
- Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (IT); (MA)
| | - Kirsten Cooper
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Laura Pereira
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (IT); (MA)
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49
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Nalcn Is a "Leak" Sodium Channel That Regulates Excitability of Brainstem Chemosensory Neurons and Breathing. J Neurosci 2017; 36:8174-87. [PMID: 27488637 DOI: 10.1523/jneurosci.1096-16.2016] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/15/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED The activity of background potassium and sodium channels determines neuronal excitability, but physiological roles for "leak" Na(+) channels in specific mammalian neurons have not been established. Here, we show that a leak Na(+) channel, Nalcn, is expressed in the CO2/H(+)-sensitive neurons of the mouse retrotrapezoid nucleus (RTN) that regulate breathing. In RTN neurons, Nalcn expression correlated with higher action potential discharge over a more alkalized range of activity; shRNA-mediated depletion of Nalcn hyperpolarized RTN neurons, and reduced leak Na(+) current and firing rate. Nalcn depletion also decreased RTN neuron activation by the neuropeptide, substance P, without affecting pH-sensitive background K(+) currents or activation by a cotransmitter, serotonin. In vivo, RTN-specific knockdown of Nalcn reduced CO2-evoked neuronal activation and breathing; hypoxic hyperventilation was unchanged. Thus, Nalcn regulates RTN neuronal excitability and stimulation by CO2, independent of direct pH sensing, potentially contributing to respiratory effects of Nalcn mutations; transmitter modulation of Nalcn may underlie state-dependent changes in breathing and respiratory chemosensitivity. SIGNIFICANCE STATEMENT Breathing is an essential, enduring rhythmic motor activity orchestrated by dedicated brainstem circuits that require tonic excitatory drive for their persistent function. A major source of drive is from a group of CO2/H(+)-sensitive neurons in the retrotrapezoid nucleus (RTN), whose ongoing activity is critical for breathing. The ionic mechanisms that support spontaneous activity of RTN neurons are unknown. We show here that Nalcn, a unique channel that generates "leak" sodium currents, regulates excitability and neuromodulation of RTN neurons and CO2-stimulated breathing. Thus, this work defines a specific function for this enigmatic channel in an important physiological context.
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50
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Moose DL, Haase SJ, Aldrich BT, Lear BC. The Narrow Abdomen Ion Channel Complex Is Highly Stable and Persists from Development into Adult Stages to Promote Behavioral Rhythmicity. Front Cell Neurosci 2017. [PMID: 28634443 PMCID: PMC5459923 DOI: 10.3389/fncel.2017.00159] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The sodium leak channel NARROW ABDOMEN (NA)/ NALCN is an important component of circadian pacemaker neuronal output. In Drosophila, rhythmic expression of the NA channel regulator Nlf-1 in a subset of adult pacemaker neurons has been proposed to contribute to circadian regulation of channel localization or activity. Here we have restricted expression of Drosophila NA channel subunits or the Nlf-1 regulator to either development or adulthood using the temperature-inducible tubulin-GAL80ts system. Surprisingly, we find that developmental expression of endogenous channel subunits and Nlf-1 is sufficient to promote robust rhythmic behavior in adults. Moreover, we find that channel complex proteins produced during development persist in the Drosophila head with little decay for at least 5-7 days in adults. In contrast, restricting either endogenous or transgenic gene expression to adult stages produces only limited amounts of the functional channel complex. These data indicate that much of the NA channel complex that functions in adult circadian neurons is normally produced during development, and that the channel complex is very stable in most neurons in the Drosophila brain. Based on these findings, we propose that circadian regulation of NA channel function in adult pacemaker neurons is mediated primarily by post-translational mechanisms that are independent of Nlf-1.
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Affiliation(s)
- Devon L Moose
- Department of Biology, University of Iowa, Iowa CityIA, United States
| | - Stephanie J Haase
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa CityIA, United States
| | | | - Bridget C Lear
- Department of Biology, University of Iowa, Iowa CityIA, United States.,Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa CityIA, United States
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