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Liu J, Bonnard E, Scholz M. Adapting and optimizing GCaMP8f for use in Caenorhabditis elegans. Genetics 2024; 228:iyae125. [PMID: 39074213 PMCID: PMC11457936 DOI: 10.1093/genetics/iyae125] [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: 06/10/2024] [Revised: 07/17/2024] [Accepted: 07/17/2024] [Indexed: 07/31/2024] Open
Abstract
Improved genetically encoded calcium indicators (GECIs) are essential for capturing intracellular dynamics of both muscle and neurons. A novel set of GECIs with ultrafast kinetics and high sensitivity was recently reported by Zhang et al. (2023). While these indicators, called jGCaMP8, were demonstrated to work in Drosophila and mice, data for Caenorhabditis elegans were not reported. Here, we present an optimized construct for C. elegans and use this to generate several strains expressing GCaMP8f (fast variant of the indicator). Utilizing the myo-2 promoter, we compare pharyngeal muscle activity measured with GCaMP7f and GCaMP8f and find that GCaMP8f is brighter upon binding to calcium, shows faster kinetics, and is not disruptive to the intrinsic contraction dynamics of the pharynx. Additionally, we validate its application for detecting neuronal activity in touch receptor neurons which reveals robust calcium transients even at small stimulus amplitudes. As such, we establish GCaMP8f as a potent tool for C. elegans research which is capable of extracting fast calcium dynamics at very low magnifications across multiple cell types.
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Affiliation(s)
- Jun Liu
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn 53175, Germany
| | - Elsa Bonnard
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn 53175, Germany
- International Max Planck Research School for Brain and Behavior, Bonn 53175, Germany
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn 53175, Germany
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2
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Yang J, Zhou S, Yang Z, Shi X, Liu H, Yang Z, Peng D, Ding Z, Ye S. Silencing of the T-type voltage-gated calcium channel α 1 subunit by fungus-mediated RNAi altered the structure of F-actin and caused defective behaviors in Ditylenchus destructor. Mol Biol Rep 2024; 51:673. [PMID: 38787479 DOI: 10.1007/s11033-024-09626-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND T-type calcium channels, characterized as low-voltage activated (LVA) calcium channels, play crucial physiological roles across a wide range of tissues, including both the neuronal and nonneuronal systems. Using in situ hybridization and RNA interference (RNAi) techniques in vitro, we previously identified the tissue distribution and physiological function of the T-type calcium channel α1 subunit (DdCα1G) in the plant-parasitic nematode Ditylenchus destructor. METHODS AND RESULTS To further characterize the functional role of DdCα1G, we employed a combination of immunohistochemistry and fungus-mediated RNAi and found that DdCα1G was clearly distributed in stylet-related tissue, oesophageal gland-related tissue, secretory-excretory duct-related tissue and male spicule-related tissue. Silencing DdCα1G led to impairments in the locomotion, feeding, reproductive ability and protein secretion of nematodes. To confirm the defects in behavior, we used phalloidin staining to examine muscle changes in DdCα1G-RNAi nematodes. Our observations demonstrated that defective behaviors are associated with related muscular atrophy. CONCLUSION Our findings provide a deeper understanding of the physiological functions of T-type calcium channels in plant-parasitic nematodes. The T-type calcium channel can be considered a promising target for sustainable nematode management practices.
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Affiliation(s)
- Jiahao Yang
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Siyu Zhou
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Ziqi Yang
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Xuqi Shi
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Haoran Liu
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Zhuhong Yang
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
- Hunan Provincial Engineering & Technology Research Center for Biopesticide and Formulation Processing, Changsha, Hunan, 410128, China
| | - Deliang Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Zhong Ding
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China.
- Hunan Provincial Engineering & Technology Research Center for Biopesticide and Formulation Processing, Changsha, Hunan, 410128, China.
| | - Shan Ye
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China.
- Hunan Provincial Engineering & Technology Research Center for Biopesticide and Formulation Processing, Changsha, Hunan, 410128, China.
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3
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Nicoletti M, Chiodo L, Loppini A, Liu Q, Folli V, Ruocco G, Filippi S. Biophysical modeling of the whole-cell dynamics of C. elegans motor and interneurons families. PLoS One 2024; 19:e0298105. [PMID: 38551921 PMCID: PMC10980225 DOI: 10.1371/journal.pone.0298105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/13/2024] [Indexed: 04/01/2024] Open
Abstract
The nematode Caenorhabditis elegans is a widely used model organism for neuroscience. Although its nervous system has been fully reconstructed, the physiological bases of single-neuron functioning are still poorly explored. Recently, many efforts have been dedicated to measuring signals from C. elegans neurons, revealing a rich repertoire of dynamics, including bistable responses, graded responses, and action potentials. Still, biophysical models able to reproduce such a broad range of electrical responses lack. Realistic electrophysiological descriptions started to be developed only recently, merging gene expression data with electrophysiological recordings, but with a large variety of cells yet to be modeled. In this work, we contribute to filling this gap by providing biophysically accurate models of six classes of C. elegans neurons, the AIY, RIM, and AVA interneurons, and the VA, VB, and VD motor neurons. We test our models by comparing computational and experimental time series and simulate knockout neurons, to identify the biophysical mechanisms at the basis of inter and motor neuron functioning. Our models represent a step forward toward the modeling of C. elegans neuronal networks and virtual experiments on the nematode nervous system.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
| | - Letizia Chiodo
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Alessandro Loppini
- Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Qiang Liu
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Viola Folli
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
- D-tails s.r.l., Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Istituto Italiano di Tecnologia, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), Florence, Italy
- ICRANet—International Center for Relativistic Astrophysics Network, Pescara, Italy
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4
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Sherman D, Harel D. Deciphering the underlying mechanisms of the pharyngeal pumping motions in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2024; 121:e2302660121. [PMID: 38315866 PMCID: PMC10873627 DOI: 10.1073/pnas.2302660121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 12/29/2023] [Indexed: 02/07/2024] Open
Abstract
The pharynx of the nematode Caenorhabditis elegans is a neuromuscular organ that exhibits typical pumping motions, which result in the intake of food particles from the environment. In-depth inspection reveals slightly different dynamics at the various pharyngeal areas, rather than synchronous pumping motions of the whole organ, which are important for its effective functioning. While the different pumping dynamics are well characterized, the underlying mechanisms that generate them are not known. In this study, the C. elegans pharynx was modeled in a bottom-up fashion, including all of the underlying biological processes that lead to, and including, its end function, food intake. The mathematical modeling of all processes allowed performing comprehensive, quantitative analyses of the system as a whole. Our analyses provided detailed explanations for the various pumping dynamics generated at the different pharyngeal areas; a fine-resolution description of muscle dynamics, both between and within different pharyngeal areas; a quantitative assessment of the values of many parameters of the system that are unavailable in the literature; and support for a functional role of the marginal cells, which are currently assumed to mainly have a structural role in the pharynx. In addition, our model predicted that in tiny organisms such as C. elegans, the generation of long-lasting action potentials must involve ions other than calcium. Our study exemplifies the power of mathematical models, which allow a more accurate, higher-resolution inspection of the studied system, and an easier and faster execution of in silico experiments than feasible in the lab.
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Affiliation(s)
- Dana Sherman
- Department of Computer Science and Applied Mathematics, Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot76100, Israel
| | - David Harel
- Department of Computer Science and Applied Mathematics, Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot76100, Israel
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5
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Yano Y, Fukuoka R, Maturana AD, Ohdachi SD, Kita M. Mammalian neurotoxins, Blarina paralytic peptides, cause hyperpolarization of human T-type Ca channel hCa v3.2 activation. J Biol Chem 2023; 299:105066. [PMID: 37468103 PMCID: PMC10493266 DOI: 10.1016/j.jbc.2023.105066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023] Open
Abstract
Among the rare venomous mammals, the short-tailed shrew Blarina brevicauda has been suggested to produce potent neurotoxins in its saliva to effectively capture prey. Several kallikrein-like lethal proteases have been identified, but the active substances of B. brevicauda remained unclear. Here, we report Blarina paralytic peptides (BPPs) 1 and 2 isolated from its submaxillary glands. Synthetic BPP2 showed mealworm paralysis and a hyperpolarization shift (-11 mV) of a human T-type Ca2+ channel (hCav3.2) activation. The amino acid sequences of BPPs were similar to those of synenkephalins, which are precursors of brain opioid peptide hormones that are highly conserved among mammals. However, BPPs rather resembled centipede neurotoxic peptides SLPTXs in terms of disulfide bond connectivity and stereostructure. Our results suggested that the neurotoxin BPPs were the result of convergent evolution as homologs of nontoxic endogenous peptides that are widely conserved in mammals. This finding is of great interest from the viewpoint of the chemical evolution of vertebrate venoms.
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Affiliation(s)
- Yusuke Yano
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Ryo Fukuoka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Andres D Maturana
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Satoshi D Ohdachi
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Masaki Kita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
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Cao X, Xie Y, Yang H, Sun P, Xue B, Garcia LR, Zhang L. EAT-2 attenuates C. elegans development via metabolic remodeling in a chemically defined food environment. Cell Mol Life Sci 2023; 80:205. [PMID: 37450052 PMCID: PMC11072272 DOI: 10.1007/s00018-023-04849-x] [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: 04/12/2023] [Revised: 05/29/2023] [Accepted: 06/25/2023] [Indexed: 07/18/2023]
Abstract
Dietary intake and nutrient composition regulate animal growth and development; however, the underlying mechanisms remain elusive. Our previous study has shown that either the mammalian deafness homolog gene tmc-1 or its downstream acetylcholine receptor gene eat-2 attenuates Caenorhabditis elegans development in a chemically defined food CeMM (C. elegans maintenance medium) environment, but the underpinning mechanisms are not well-understood. Here, we found that, in CeMM food environment, for both eat-2 and tmc-1 fast-growing mutants, several fatty acid synthesis and elongation genes were highly expressed, while many fatty acid β-oxidation genes were repressed. Accordingly, dietary supplementation of individual fatty acids, such as monomethyl branch chain fatty acid C17ISO, palmitic acid and stearic acid significantly promoted wild-type animal development on CeMM, and mutations in either C17ISO synthesis gene elo-5 or elo-6 slowed the rapid growth of eat-2 mutant. Tissue-specific rescue experiments showed that elo-6 promoted animal development mainly in the intestine. Furthermore, transcriptome and metabolome analyses revealed that elo-6/C17ISO regulation of C. elegans development may be correlated with up-regulating expression of cuticle synthetic and hedgehog signaling genes, as well as promoting biosynthesis of amino acids, amino acid derivatives and vitamins. Correspondingly, we found that amino acid derivative S-adenosylmethionine and its upstream metabolite methionine sulfoxide significantly promoted C. elegans development on CeMM. This study demonstrated that C17ISO, palmitic acid, stearic acid, S-adenosylmethionine and methionine sulfoxide inhibited or bypassed the TMC-1 and EAT-2-mediated attenuation of development via metabolic remodeling, and allowed the animals to adapt to the new nutritional niche.
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Affiliation(s)
- Xuwen Cao
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, 266237, Qingdao, China
| | - Yusu Xie
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China
| | - Hanwen Yang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China
| | - Peiqi Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Beining Xue
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - L Rene Garcia
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Liusuo Zhang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071, Qingdao, China.
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, China.
- Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, 266071, Qingdao, China.
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7
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Bergs ACF, Liewald JF, Rodriguez-Rozada S, Liu Q, Wirt C, Bessel A, Zeitzschel N, Durmaz H, Nozownik A, Dill H, Jospin M, Vierock J, Bargmann CI, Hegemann P, Wiegert JS, Gottschalk A. All-optical closed-loop voltage clamp for precise control of muscles and neurons in live animals. Nat Commun 2023; 14:1939. [PMID: 37024493 PMCID: PMC10079764 DOI: 10.1038/s41467-023-37622-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
Excitable cells can be stimulated or inhibited by optogenetics. Since optogenetic actuation regimes are often static, neurons and circuits can quickly adapt, allowing perturbation, but not true control. Hence, we established an optogenetic voltage-clamp (OVC). The voltage-indicator QuasAr2 provides information for fast, closed-loop optical feedback to the bidirectional optogenetic actuator BiPOLES. Voltage-dependent fluorescence is held within tight margins, thus clamping the cell to distinct potentials. We established the OVC in muscles and neurons of Caenorhabditis elegans, and transferred it to rat hippocampal neurons in slice culture. Fluorescence signals were calibrated to electrically measured potentials, and wavelengths to currents, enabling to determine optical I/V-relationships. The OVC reports on homeostatically altered cellular physiology in mutants and on Ca2+-channel properties, and can dynamically clamp spiking in C. elegans. Combining non-invasive imaging with control capabilities of electrophysiology, the OVC facilitates high-throughput, contact-less electrophysiology in individual cells and paves the way for true optogenetic control in behaving animals.
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Affiliation(s)
- Amelie C F Bergs
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Silvia Rodriguez-Rozada
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Qiang Liu
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA
- Department of Neuroscience, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Christin Wirt
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Artur Bessel
- Independent Researcher, Melatener Strasse 93, 52074, Aachen, Germany
| | - Nadja Zeitzschel
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Hilal Durmaz
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Adrianna Nozownik
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Holger Dill
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany
| | - Maëlle Jospin
- Université Claude Bernard Lyon 1, Institut NeuroMyoGène, 8 Avenue Rockefeller, 69008, Lyon, France
| | - Johannes Vierock
- Institute for Biology, Experimental Biophysics, Humboldt University, 10115, Berlin, Germany
| | - Cornelia I Bargmann
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA
- Chan Zuckerberg Initiative, Palo Alto, CA, USA
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt University, 10115, Berlin, Germany
| | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
- Medical Faculty Mannheim, University of Heidelberg, Ludolf-Krehl-Strasse 13-17, 68167, Mannheim, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438, Frankfurt, Germany.
- Institute of Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438, Frankfurt, Germany.
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Wang M, Zhang Z, Sun N, Yang B, Mo J, Wang D, Su M, Hu J, Wang M, Wang L. Gold Nanoparticles Reduce Food Sensation in Caenorhabditis elegans via the Voltage-Gated Channel EGL-19. Int J Nanomedicine 2023; 18:1659-1676. [PMID: 37020688 PMCID: PMC10069523 DOI: 10.2147/ijn.s394666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
Introduction The increasing use of gold nanoparticles (Au NPs) in the medical field has raised concerns about the potential adverse effect of Au NPs exposure. However, it is difficult to assess the health risks of Au NPs exposure at the individual organ level using current measurement techniques. Methods The physical and chemical properties of Au NPs were characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR), and zeta sizer. The RNA-seq data of Au NPs-exposed worms were analyzed. The food intake was measured by liquid culture and Pharyngeal pumping rate. The function of the smell and taste neurons was evaluated by the chemotaxis and avoidance assay. The activation of ASE neurons was analyzed by calcium imaging. The gene expression of ins-22 and egl-19 was obtained from the C. elegans single cell RNA-seq databases. Results Our data analysis indicated that 62.8% of the significantly altered genes were functional in the nervous system. Notably, developmental stage analysis demonstrated that exposure to Au NPs interfered with animal development by regulating foraging behavior. Also, our chemotaxis results showed that exposure to Au NPs reduced the sensation of C. elegans to NaCl, which was consistent with the decrease in calcium transit of ASEL. Further studies confirmed that the reduced calcium transit was dependent on voltage-gated calcium channel EGL-19. The neuropeptide INS-22 was partially involved in Au NPs-induced NaCl sensation defect. Therefore, we proposed that Au NPs reduced the calcium transit in the ASEL neuron through egl-19-dependent calcium channels. It was partially regulated by the DAF-16 targeting neuropeptide INS-22. Discussion Our results demonstrate that Au NPs affect food sensation by reducing the calcium transit in ASEL neurons, which further leads to reduced pharynx pumping and feeding defects. The toxicology studies of Au NPs from worms have great potential to guide the usage of Au NPs in the medical field such as targeted drug delivery.
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Affiliation(s)
- Meimei Wang
- Department of Pathophysiology, School of Basic Medical Science, Anhui Medical University, Hefei, Anhui, 230032, People’s Republic of China
| | - Zhenzhen Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, People’s Republic of China
| | - Ning Sun
- Institute of Clinical Laboratory Science, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu, 210002, People’s Republic of China
| | - Baolin Yang
- Institute of Technical Biology & Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230032, People’s Republic of China
| | - Jihao Mo
- Department of Medical Laboratory, Luoyang Orthopedic Hospital of Henan Province, Orthopedic Institute of Henan Province, Luoyang, Henan, 459001, People’s Republic of China
| | - Daping Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, People’s Republic of China
| | - Mingqin Su
- Department of Pathophysiology, School of Basic Medical Science, Anhui Medical University, Hefei, Anhui, 230032, People’s Republic of China
| | - Jian Hu
- Department of Pathophysiology, School of Basic Medical Science, Anhui Medical University, Hefei, Anhui, 230032, People’s Republic of China
| | - Miaomiao Wang
- School of Medical Science, Huang He Science and Technology University, Zhengzhou, Henan, 459001, People’s Republic of China
| | - Lei Wang
- School of Biological Sciences, Nanyang Technological University, Singapore, 639798, Singapore
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
- Correspondence: Lei Wang, Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA, Tel +1 786-620-1400, Email
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Cunningham KL, Littleton JT. Mechanisms controlling the trafficking, localization, and abundance of presynaptic Ca 2+ channels. Front Mol Neurosci 2023; 15:1116729. [PMID: 36710932 PMCID: PMC9880069 DOI: 10.3389/fnmol.2022.1116729] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 12/26/2022] [Indexed: 01/14/2023] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) mediate Ca2+ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (Pr ), a key presynaptic determinant of synaptic strength. Given this functional significance, defining the processes that cooperate to establish AZ VGCC abundance is critical for understanding how these mechanisms set synaptic strength and how they might be regulated to control presynaptic plasticity. VGCC abundance at AZs involves multiple steps, including channel biosynthesis (transcription, translation, and trafficking through the endomembrane system), forward axonal trafficking and delivery to synaptic terminals, incorporation and retention at presynaptic sites, and protein recycling. Here we discuss mechanisms that control VGCC abundance at synapses, highlighting findings from invertebrate and vertebrate models.
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Affiliation(s)
- Karen L. Cunningham
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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Dube F, Hinas A, Delhomme N, Åbrink M, Svärd S, Tydén E. Transcriptomics of ivermectin response in Caenorhabditis elegans: Integrating abamectin quantitative trait loci and comparison to the Ivermectin-exposed DA1316 strain. PLoS One 2023; 18:e0285262. [PMID: 37141255 PMCID: PMC10159168 DOI: 10.1371/journal.pone.0285262] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/18/2023] [Indexed: 05/05/2023] Open
Abstract
Parasitic nematodes pose a significant threat to human and animal health, as well as cause economic losses in the agricultural sector. The use of anthelmintic drugs, such as Ivermectin (IVM), to control these parasites has led to widespread drug resistance. Identifying genetic markers of resistance in parasitic nematodes can be challenging, but the free-living nematode Caenorhabditis elegans provides a suitable model. In this study, we aimed to analyze the transcriptomes of adult C. elegans worms of the N2 strain exposed to the anthelmintic drug Ivermectin (IVM), and compare them to those of the resistant strain DA1316 and the recently identified Abamectin Quantitative Trait Loci (QTL) on chromosome V. We exposed pools of 300 adult N2 worms to IVM (10-7 and 10-8 M) for 4 hours at 20°C, extracted total RNA and sequenced it on the Illumina NovaSeq6000 platform. Differentially expressed genes (DEGs) were determined using an in-house pipeline. The DEGs were compared to genes from a previous microarray study on IVM-resistant C. elegans and Abamectin-QTL. Our results revealed 615 DEGs (183 up-regulated and 432 down-regulated genes) from diverse gene families in the N2 C. elegans strain. Of these DEGs, 31 overlapped with genes from IVM-exposed adult worms of the DA1316 strain. We identified 19 genes, including the folate transporter (folt-2) and the transmembrane transporter (T22F3.11), which exhibited an opposite expression in N2 and the DA1316 strain and were deemed potential candidates. Additionally, we compiled a list of potential candidates for further research including T-type calcium channel (cca-1), potassium chloride cotransporter (kcc-2), as well as other genes such as glutamate-gated channel (glc-1) that mapped to the Abamectin-QTL.
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Affiliation(s)
- Faruk Dube
- Department of Biomedical Sciences and Veterinary Public Health, Division of Parasitology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Andrea Hinas
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Nicolas Delhomme
- Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Magnus Åbrink
- Department of Biomedical Sciences and Veterinary Public Health, Section of Immunology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Eva Tydén
- Department of Biomedical Sciences and Veterinary Public Health, Division of Parasitology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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11
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Chen D, Cheng H, Liu S, Al-Sheikh U, Fan Y, Duan D, Zou W, Zhu L, Kang L. The Voltage-Gated Calcium Channel EGL-19 Acts on Glia to Drive Olfactory Adaptation. Front Mol Neurosci 2022; 15:907064. [PMID: 35782381 PMCID: PMC9247319 DOI: 10.3389/fnmol.2022.907064] [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: 03/29/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Calcium channelopathies have been strongly linked to cardiovascular, muscular, neurological and psychiatric disorders. The voltage-gated calcium channels (VGCC) are vital transducers of membrane potential changes to facilitate the dynamics of calcium ions and release of neurotransmitter. Whether these channels function in the glial cell to mediate calcium variations and regulate behavioral outputs, is poorly understood. Our results showed that odorant and mechanical stimuli evoked robust calcium increases in the amphid sheath (AMsh) glia from C. elegans, which were largely dependent on the L-Type VGCC EGL-19. Moreover, EGL-19 modulates the morphologies of both ASH sensory neurons and AMsh glia. Tissue-specific knock-down of EGL-19 in AMsh glia regulated sensory adaptability of ASH neurons and promoted olfactory adaptation. Our results reveal a novel role of glial L-Type VGCC EGL-19 on olfaction, lead to improved understanding of the functions of VGCCs in sensory transduction.
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Affiliation(s)
- Du Chen
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Hankui Cheng
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Siyan Liu
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yuedan Fan
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Duo Duan
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Wenjuan Zou
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Linhui Zhu
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Lijun Kang
- Department of Neurobiology and Department of Neurology of the Fourth Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
- *Correspondence: Lijun Kang
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Jiang J, Su Y, Zhang R, Li H, Tao L, Liu Q. C. elegans enteric motor neurons fire synchronized action potentials underlying the defecation motor program. Nat Commun 2022; 13:2783. [PMID: 35589790 PMCID: PMC9120479 DOI: 10.1038/s41467-022-30452-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
C. elegans neurons were thought to be non-spiking until our recent discovery of action potentials in the sensory neuron AWA; however, the extent to which the C. elegans nervous system relies on analog or digital coding is unclear. Here we show that the enteric motor neurons AVL and DVB fire synchronous all-or-none calcium-mediated action potentials following the intestinal pacemaker during the rhythmic C. elegans defecation behavior. AVL fires unusual compound action potentials with each depolarizing calcium spike mediated by UNC-2 followed by a hyperpolarizing potassium spike mediated by a repolarization-activated potassium channel EXP-2. Simultaneous behavior tracking and imaging in free-moving animals suggest that action potentials initiated in AVL propagate along its axon to activate precisely timed DVB action potentials through the INX-1 gap junction. This work identifies a novel circuit of spiking neurons in C. elegans that uses digital coding for long-distance communication and temporal synchronization underlying reliable behavioral rhythm.
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Affiliation(s)
- Jingyuan Jiang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yifan Su
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Ruilin Zhang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
- Yuanpei College, Peking University, Beijing, 100871, China
| | - Haiwen Li
- LMAM, School of Mathematical Sciences, Peking University, Beijing, 100871, China
| | - Louis Tao
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Beijing, 100871, China
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Qiang Liu
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY, 10065, USA.
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR.
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13
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Paul S, Balakrishnan S, Arumugaperumal A, Lathakumari S, Syamala SS, Vijayan V, Durairaj SCJ, Arumugaswami V, Sivasubramaniam S. Importance of clitellar tissue in the regeneration ability of earthworm Eudrilus eugeniae. Funct Integr Genomics 2022; 22:1-32. [PMID: 35416560 DOI: 10.1007/s10142-022-00849-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/04/2022]
Abstract
Among the annelids, earthworms are renowned for their phenomenal ability to regenerate the lost segments. The adult earthworm Eudrilus eugeniae contains 120 segments and the body segments of the earthworm are divided into pre-clitellar, clitellar and post-clitellar segments. The present study denoted that clitellum plays vital role in the successful regeneration of the species. We have performed histological studies to identify among the three skin layers of the earthworm, which cellular layer supports the blastema formation and regeneration of the species. The histological evidences denoted that the proliferation of the longitudinal cell layer at the amputation site is crucial for the successful regeneration of the earthworm and it takes place only in the presence of an intact clitellum. Besides we have performed clitellar transcriptome analysis of the earthworm Eudrilus eugeniae to monitor the key differentially expressed genes and their associated functions and pathways controlling the clitellar tissue changes during both anterior and posterior regeneration of the earthworm. A total of 4707 differentially expressed genes (DEGs) were identified between the control clitellum and clitellum of anterior regenerated earthworms and 4343 DEGs were detected between the control clitellum and clitellum of posterior regenerated earthworms. The functional enrichment analysis confirmed the genes regulating the muscle mass shape and structure were significantly downregulated and the genes associated with response to starvation and anterior-posterior axis specification were significantly upregulated in the clitellar tissue during both anterior and posterior regeneration of the earthworm. The RNA sequencing data of clitellum and the comparative transcriptomic analysis were helpful to understand the complex regeneration process of the earthworm.
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Affiliation(s)
- Sayan Paul
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.,Centre for Cardiovascular Biology and Disease, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India
| | | | - Arun Arumugaperumal
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Saranya Lathakumari
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Sandhya Soman Syamala
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Vijithkumar Vijayan
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Selvan Christyraj Jackson Durairaj
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.,Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, 600 119, India
| | | | - Sudhakar Sivasubramaniam
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.
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Engel MA, Wörmann YR, Kaestner H, Schüler C. An Optogenetic Arrhythmia Model—Insertion of Several Catecholaminergic Polymorphic Ventricular Tachycardia Mutations Into Caenorhabditis elegans UNC-68 Disturbs Calstabin-Mediated Stabilization of the Ryanodine Receptor Homolog. Front Physiol 2022; 13:691829. [PMID: 35399287 PMCID: PMC8990320 DOI: 10.3389/fphys.2022.691829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 02/15/2022] [Indexed: 11/14/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disturbance of the heart rhythm (arrhythmia) that is induced by stress or that occurs during exercise. Most mutations that have been linked to CPVT are found in two genes, i.e., ryanodine receptor 2 (RyR2) and calsequestrin 2 (CASQ2), two proteins fundamentally involved in the regulation of intracellular Ca2+ in cardiac myocytes. We inserted six CPVT-causing mutations via clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 into unc-68 and csq-1, the Caenorhabditis elegans homologs of RyR and CASQ, respectively. We characterized those mutations via video-microscopy, electrophysiology, and calcium imaging in our previously established optogenetic arrhythmia model. In this study, we additionally enabled high(er) throughput recordings of intact animals by combining optogenetic stimulation with a microfluidic chip system. Whereas only minor/no pump deficiency of the pharynx was observed at baseline, three mutations of UNC-68 (S2378L, P2460S, Q4623R; RyR2-S2246L, -P2328S, -Q4201R) reduced the ability of the organ to follow 4 Hz optogenetic stimulation. One mutation (Q4623R) was accompanied by a strong reduction of maximal pump rate. In addition, S2378L and Q4623R evoked an altered calcium handling during optogenetic stimulation. The 1,4-benzothiazepine S107, which is suggested to stabilize RyR2 channels by enhancing the binding of calstabin2, reversed the reduction of pumping ability in a mutation-specific fashion. However, this depends on the presence of FKB-2, a C. elegans calstabin2 homolog, indicating the involvement of calstabin2 in the disease-causing mechanisms of the respective mutations. In conclusion, we showed for three CPVT-like mutations in C. elegans RyR a reduced pumping ability upon light stimulation, i.e., an arrhythmia-like phenotype, that can be reversed in two cases by the benzothiazepine S107 and that depends on stabilization via FKB-2. The genetically amenable nematode in combination with optogenetics and high(er) throughput recordings is a promising straightforward system for the investigation of RyR mutations and the selection of mutation-specific drugs.
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Affiliation(s)
- Marcial Alexander Engel
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Yves René Wörmann
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Hanna Kaestner
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
- *Correspondence: Christina Schüler,
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15
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Widaad A, Zulkipli IN, Petalcorin MIR. Anthelmintic Effect of Leucaena leucocephala Extract and Its Active Compound, Mimosine, on Vital Behavioral Activities in Caenorhabditis elegans. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27061875. [PMID: 35335240 PMCID: PMC8950933 DOI: 10.3390/molecules27061875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/22/2022] [Accepted: 03/07/2022] [Indexed: 12/03/2022]
Abstract
Helminth infections continue to be a neglected global threat in tropical regions, and there have been growing cases of anthelmintic resistance reported towards the existing anthelmintic drugs. Thus, the search for a novel anthelmintic agent has been increasing, especially those derived from plants. Leucaena leucocephala (LL) is a leguminous plant that is known to have several pharmacological activities, including anthelmintic activity. It is widely known to contain a toxic compound called mimosine, which we believed could be a potential lead candidate that could exert a potent anthelmintic effect. Hence, this study aimed to validate the presence of mimosine in LL extract and to investigate the anthelmintic effect of LL extract and mimosine on head thrashing, egg-laying, and pharyngeal pumping activities using the animal model Caenorhabditis elegans (C. elegans). Mimosine content in LL extract was confirmed through an HPLC analysis of spiking LL extract with different mimosine concentrations, whereby an increasing trend in peak heights was observed at a retention time of 0.9 min. LL extract and mimosine caused a significant dose-dependent increase in the percentage of worm mortality, which produced LC50s of 73 mg/mL and 6.39 mg/mL, respectively. Exposure of C. elegans to different concentrations of LL extract and mimosine significantly decreased the head thrashing, egg-laying, and mean pump amplitude of pharyngeal pumping activity. We speculated that these behavioral changes are due to the inhibitory effect of LL extract and mimosine on an L-type calcium channel called EGL-19. Our findings provide evidential support for the potential of LL extract and its active compound, mimosine, as novel anthelmintic candidates. However, the underlying mechanism of the anthelmintic action has yet to be elucidated.
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Hori S, Mitani S. The transcription factor unc-130/FOXD3/4 contributes to the biphasic calcium response required to optimize avoidance behavior. Sci Rep 2022; 12:1907. [PMID: 35115609 PMCID: PMC8814005 DOI: 10.1038/s41598-022-05942-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 01/13/2022] [Indexed: 11/12/2022] Open
Abstract
The central neural network optimizes avoidance behavior depending on the nociceptive stimulation intensity and is essential for survival. How the property of hub neurons that enables the selection of behaviors is genetically defined is not well understood. We show that the transcription factor unc-130, a human FOXD3/4 ortholog, is required to optimize avoidance behavior depending on stimulus strength in Caenorhabditis elegans. unc-130 is necessary for both ON responses (calcium decreases) and OFF responses (calcium increases) in AIBs, central neurons of avoidance optimization. Ablation of predicted upstream inhibitory neurons reduces the frequency of turn behavior, suggesting that optimization needs both calcium responses. At the molecular level, unc-130 upregulates the expression of at least three genes: nca-2, a homolog of the vertebrate cation leak channel NALCN; glr-1, an AMPA-type glutamate receptor; and eat-4, a hypothetical L-glutamate transmembrane transporter in the central neurons of optimization. unc-130 shows more limited regulation in optimizing behavior than an atonal homolog lin-32, and unc-130 and lin-32 appear to act in parallel molecular pathways. Our findings suggest that unc-130 is required for the establishment of some AIB identities to optimize avoidance behavior.
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Affiliation(s)
- Sayaka Hori
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo, 162-8666, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo, 162-8666, Japan.
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Co-Silencing of the Voltage-Gated Calcium Channel β Subunit and High-Voltage Activated α 1 Subunit by dsRNA Soaking Resulted in Enhanced Defects in Locomotion, Stylet Thrusting, Chemotaxis, Protein Secretion, and Reproduction in Ditylenchus destructor. Int J Mol Sci 2022; 23:ijms23020784. [PMID: 35054970 PMCID: PMC8776034 DOI: 10.3390/ijms23020784] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 12/29/2022] Open
Abstract
The voltage-gated calcium channel (VGCC) β subunit (Cavβ) protein is a kind of cytosolic auxiliary subunit that plays an important role in regulating the surface expression and gating characteristics of high-voltage-activated (HVA) calcium channels. Ditylenchus destructor is an important plant-parasitic nematode. In the present study, the putative Cavβ subunit gene of D. destructor, namely, DdCavβ, was subjected to molecular characterization. In situ hybridization assays showed that DdCavβ was expressed in all nematode tissues. Transcriptional analyses showed that DdCavβ was expressed during each developmental stage of D. destructor, and the highest expression level was recorded in the third-stage juveniles. The crucial role of DdCavβ was verified by dsRNA soaking-mediated RNA interference (RNAi). Silencing of DdCavβ or HVA Cavα1 alone and co-silencing of the DdCavβ and HVA Cavα1 genes resulted in defective locomotion, stylet thrusting, chemotaxis, protein secretion and reproduction in D. destructor. Co-silencing of the HVA Cavα1 and Cavβ subunits showed stronger interference effects than single-gene silencing. This study provides insights for further study of VGCCs in plant-parasitic nematodes.
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Liu H, Qiu Y, Wang D. Alteration in expressions of ion channels in Caenorhabditis elegans exposed to polystyrene nanoparticles. CHEMOSPHERE 2021; 273:129686. [PMID: 33486351 DOI: 10.1016/j.chemosphere.2021.129686] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/28/2020] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Ion channels on cytoplasmic membrane function to sense various environmental stimuli. We here determined the changes of genes encoding ion channels in Caenorhabditis elegans after exposure to polystyrene nanoparticles (PS-NPs). Exposure to 1-1000 μg/L PS-NPs could increase expressions of egl-19, mec-10, trp-4, trp-2, tax-4, cca-1, unc-2, and unc-93, and decrease the expressions of cng-3, mec-6, ocr-2, deg-1, exc-4, kvs-1, and eat-2. Among these 15 ion channel genes, RNAi knockdown of cng-3 or eat-2 caused resistance to PS-NPs toxicity and RNAi knockdown of egl-19, cca-1, tax-4, or unc-93 induced susceptibility to PS-NPs toxicity, suggesting that cng-3, eat-2, egl-19, cca-1, tax-4, and unc-93 were involved in the control of PS-NPs toxicity. EGL-19 and CCA-1 functioned in intestinal cells to control PS-NPs toxicity, and CNG-3, EAT-2, EGL-19, TAX-4, and UNC-93 functioned in neuronal cells to control PS-NPs. Moreover, in intestinal cells of PS-NPs exposed worms, cca-1 RNAi knockdown decreased elt-2 expression, and egl-19 RNAi knockdown decreased daf-16 and elt-2 expressions. In neuronal cells of PS-NPs exposed worms, eat-2 RNAi knockdown increased jnk-1, mpk-1, and dbl-1 expressions, unc-93 RNAi knockdown decreased mpk-1 and daf-7 expressions, and tax-4 RNAi knockdown decreased jnk-1 and daf-7 expressions. Therefore, two molecular networks mediated by ion channels in intestinal cells and neuronal cells were dysregulated by PS-NPs exposure in C. elegans. Our data suggested that the dysregulation in expressions of these ion channels mediated a protective response to PS-NPs in the range of μg/L in worms.
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Affiliation(s)
- Huanliang Liu
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China
| | - Yuexiu Qiu
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China; Shenzhen Ruipuxun Academy for Stem Cell & Regenerative Medicine, Shenzhen, 518122, China; College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, 404100, China.
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Bhagat J, Nishimura N, Shimada Y. Worming into a robust model to unravel the micro/nanoplastic toxicity in soil: A review on Caenorhabditis elegans. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2021.116235] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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20
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Giunti S, Andersen N, Rayes D, De Rosa MJ. Drug discovery: Insights from the invertebrate Caenorhabditis elegans. Pharmacol Res Perspect 2021; 9:e00721. [PMID: 33641258 PMCID: PMC7916527 DOI: 10.1002/prp2.721] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/06/2021] [Indexed: 12/18/2022] Open
Abstract
Therapeutic drug development is a long, expensive, and complex process that usually takes 12-15 years. In the early phases of drug discovery, in particular, there is a growing need for animal models that ensure the reduction in both cost and time. Caenorhabditis elegans has been traditionally used to address fundamental aspects of key biological processes, such as apoptosis, aging, and gene expression regulation. During the last decade, with the advent of large-scale platforms for screenings, this invertebrate has also emerged as an essential tool in the pharmaceutical research industry to identify novel drugs and drug targets. In this review, we discuss the reasons why C. elegans has been positioned as an outstanding cost-effective option for drug discovery, highlighting both the advantages and drawbacks of this model. Particular attention is paid to the suitability of this nematode in large-scale genetic and pharmacological screenings. High-throughput screenings in C. elegans have indeed contributed to the breakthrough of a wide variety of candidate compounds involved in extensive fields including neurodegeneration, pathogen infections and metabolic disorders. The versatility of this nematode, which enables its instrumentation as a model of human diseases, is another attribute also herein underscored. As illustrative examples, we discuss the utility of C. elegans models of both human neurodegenerative diseases and parasitic nematodes in the drug discovery industry. Summing up, this review aims to demonstrate the impact of C. elegans models on the drug discovery pipeline.
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Affiliation(s)
- Sebastián Giunti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - Natalia Andersen
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - Diego Rayes
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - María José De Rosa
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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22
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Retrogradely transmitted α-synuclein is taken up by the endophilin-independent endocytosis in the C. elegans neural circuit. Biochem Biophys Res Commun 2021; 552:176-182. [PMID: 33751935 DOI: 10.1016/j.bbrc.2021.03.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 11/23/2022]
Abstract
α-Synuclein is a major component of Lewy bodies and Lewy neuritis which are hallmarks of Parkinson's disease, and is known to propagate from cell-to-cell in a prion-like manner. However, the exact mechanism of α-synuclein propagation in cells remains unclear. Despite the increasing number of studies and models of α-synuclein propagation, there is no direct evidence demonstrating whether the propagation is trans-synaptic or synaptic connection-independent, what the direction of propagation is, and what the regulators of α-synuclein propagation are. In this study, we generated a Caenorhabditis elegans model that can help monitoring the neuron-to-neuron propagation of α-synuclein using BiFC system. Using this model, we demonstrated that α-synuclein was propagated into neurons in both anterograde and retrograde manners, with retrograde propagation being dominant. Interestingly, we also found that endophilin, which is a protein required for classical clathrin-mediated endocytic machinery, was not involved in this retrograde propagation. Furthermore, we demonstrated that α-synuclein inhibits neuronal activity through voltage-gated calcium channels. Our findings suggest a possible mechanism for α-synuclein propagation via synapses through a novel uptake pathway.
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23
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Gauberg J, Abdallah S, Elkhatib W, Harracksingh AN, Piekut T, Stanley EF, Senatore A. Conserved biophysical features of the Ca V2 presynaptic Ca 2+ channel homologue from the early-diverging animal Trichoplax adhaerens. J Biol Chem 2020; 295:18553-18578. [PMID: 33097592 PMCID: PMC7939481 DOI: 10.1074/jbc.ra120.015725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
The dominant role of CaV2 voltage-gated calcium channels for driving neurotransmitter release is broadly conserved. Given the overlapping functional properties of CaV2 and CaV1 channels, and less so CaV3 channels, it is unclear why there have not been major shifts toward dependence on other CaV channels for synaptic transmission. Here, we provide a structural and functional profile of the CaV2 channel cloned from the early-diverging animal Trichoplax adhaerens, which lacks a nervous system but possesses single gene homologues for CaV1-CaV3 channels. Remarkably, the highly divergent channel possesses similar features as human CaV2.1 and other CaV2 channels, including high voltage-activated currents that are larger in external Ba2+ than in Ca2+; voltage-dependent kinetics of activation, inactivation, and deactivation; and bimodal recovery from inactivation. Altogether, the functional profile of Trichoplax CaV2 suggests that the core features of presynaptic CaV2 channels were established early during animal evolution, after CaV1 and CaV2 channels emerged via proposed gene duplication from an ancestral CaV1/2 type channel. The Trichoplax channel was relatively insensitive to mammalian CaV2 channel blockers ω-agatoxin-IVA and ω-conotoxin-GVIA and to metal cation blockers Cd2+ and Ni2+ Also absent was the capacity for voltage-dependent G-protein inhibition by co-expressed Trichoplax Gβγ subunits, which nevertheless inhibited the human CaV2.1 channel, suggesting that this modulatory capacity evolved via changes in channel sequence/structure, and not G proteins. Last, the Trichoplax channel was immunolocalized in cells that express an endomorphin-like peptide implicated in cell signaling and locomotive behavior and other likely secretory cells, suggesting contributions to regulated exocytosis.
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Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Salsabil Abdallah
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alicia N Harracksingh
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Thomas Piekut
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Elise F Stanley
- Laboratory of Synaptic Transmission, Krembil Research Institute, Toronto, Ontario, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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24
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Stringer RN, Jurkovicova-Tarabova B, Huang S, Haji-Ghassemi O, Idoux R, Liashenko A, Souza IA, Rzhepetskyy Y, Lacinova L, Van Petegem F, Zamponi GW, Pamphlett R, Weiss N. A rare CACNA1H variant associated with amyotrophic lateral sclerosis causes complete loss of Ca v3.2 T-type channel activity. Mol Brain 2020; 13:33. [PMID: 32143681 PMCID: PMC7060640 DOI: 10.1186/s13041-020-00577-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/02/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of cortical, brain stem and spinal motor neurons that leads to muscle weakness and death. A previous study implicated CACNA1H encoding for Cav3.2 calcium channels as a susceptibility gene in ALS. In the present study, two heterozygous CACNA1H variants were identified by whole genome sequencing in a small cohort of ALS patients. These variants were functionally characterized using patch clamp electrophysiology, biochemistry assays, and molecular modeling. A previously unreported c.454GTAC > G variant produced an inframe deletion of a highly conserved isoleucine residue in Cav3.2 (p.ΔI153) and caused a complete loss-of-function of the channel, with an additional dominant-negative effect on the wild-type channel when expressed in trans. In contrast, the c.3629C > T variant caused a missense substitution of a proline with a leucine (p.P1210L) and produced a comparatively mild alteration of Cav3.2 channel activity. The newly identified ΔI153 variant is the first to be reported to cause a complete loss of Cav3.2 channel function. These findings add to the notion that loss-of-function of Cav3.2 channels associated with rare CACNA1H variants may be risk factors in the complex etiology of ALS.
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Affiliation(s)
- Robin N. Stringer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Sun Huang
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Romane Idoux
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Anna Liashenko
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Ivana A. Souza
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Yuriy Rzhepetskyy
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Lubica Lacinova
- Center of Biosciences, Institute of Molecular Physiology and Genetics, Academy of Sciences, Bratislava, Slovakia
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Roger Pamphlett
- Discipline of Pathology, Brain and Mind Centre, The University of Sydney, Sydney, NSW Australia
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
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25
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Ye S, Zeng R, Zhou J, An M, Ding Z. Molecular characterization of Ditylenchus destructor voltage-gated calcium channel α1 subunits and analysis of the effect of their knockdown on nematode activity. Biochimie 2020; 171-172:91-102. [PMID: 32109501 DOI: 10.1016/j.biochi.2020.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/19/2020] [Indexed: 01/17/2023]
Abstract
Voltage-gated calcium channels (VGCCs) mediate the entry of Ca2+ ions into cells in response to membrane depolarization and play fundamental roles in the nervous system, and the α1 subunits are the main subunits of Ca2+ channels. Caenorhabditis elegans possesses genes encoding α1 subunits; however, very few of these genes have been cloned in plant-parasitic nematodes (PPNs). Ditylenchus destructor is a PPN that has been proposed as a new model for studying the biology and control of PPNs. To understand the structure and function of the VGCCs of this PPN, we first cloned and identified three full-length cDNAs of VGCC α1 subunit genes in D. destructor with the defining structural and conserved features of Cav1 (L-type), Cav2 (non-L-type) and Cav3 (T-type). In situ hybridization assays demonstrated that the Cav1 VGCC α1 subunit gene (DdCα1D) was expressed within body wall muscles. The Cav2 VGCC α1 subunit (DdCα1A) was expressed in the oesophageal gland, vulva and vas deferens of the worm, and the Cav3 VGCC α1 subunit (DdCα1G) was localized to the oesophagus and median bulb. In addition, on the basis of the in vitro knockdown of L-, non-L- and T-type genes via RNAi, these genes were predicted to play a key role in the modulation of locomotion, feeding and reproduction. After the silencing of DdCα1G, the median bulb muscle of D. destructor was obviously contracted, and its feeding and reproduction abilities were significantly inhibited. This study provides insight into the structure and function of VGCC α1 subunits in D. destructor.
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Affiliation(s)
- Shan Ye
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China; Hunan Provincial Engineering & Technology Research Center for Bio-pesticide and Formulation Processing, Changsha, Hunan, 410128, China
| | - Rune Zeng
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Jianyu Zhou
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Mingwei An
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Zhong Ding
- College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, 410128, China; Hunan Provincial Engineering & Technology Research Center for Bio-pesticide and Formulation Processing, Changsha, Hunan, 410128, China.
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26
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Rhodopsin-based voltage imaging tools for use in muscles and neurons of Caenorhabditis elegans. Proc Natl Acad Sci U S A 2019; 116:17051-17060. [PMID: 31371514 PMCID: PMC6708366 DOI: 10.1073/pnas.1902443116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuronal and other excitable cell activity is characterized by alteration in membrane voltage, while intracellular Ca2+ levels and transmitter release are affected downstream of electrical activity. Thus, the most direct way of monitoring neuronal activity is by membrane voltage. Electrophysiology is demanding for multiple cells or cell ensembles and difficult to use in live animals, thus imaging methods are desirable. Yet, genetically encoded voltage indicators fell behind Ca2+ indicators until recently, when microbial rhodopsins and derivatives were introduced as genetically encoded voltage indicators. We evaluated rhodopsin tools for voltage imaging in muscles and neurons of Caenorhabditis elegans, a prime animal model in neuro- and cell biology, showing robust performance and the ability to characterize genetic mutants. Genetically encoded voltage indicators (GEVIs) based on microbial rhodopsins utilize the voltage-sensitive fluorescence of all-trans retinal (ATR), while in electrochromic FRET (eFRET) sensors, donor fluorescence drops when the rhodopsin acts as depolarization-sensitive acceptor. In recent years, such tools have become widely used in mammalian cells but are less commonly used in invertebrate systems, mostly due to low fluorescence yields. We systematically assessed Arch(D95N), Archon, QuasAr, and the eFRET sensors MacQ-mCitrine and QuasAr-mOrange, in the nematode Caenorhabditis elegans. ATR-bearing rhodopsins reported on voltage changes in body wall muscles (BWMs), in the pharynx, the feeding organ [where Arch(D95N) showed approximately 128% ΔF/F increase per 100 mV], and in neurons, integrating circuit activity. ATR fluorescence is very dim, yet, using the retinal analog dimethylaminoretinal, it was boosted 250-fold. eFRET sensors provided sensitivities of 45 to 78% ΔF/F per 100 mV, induced by BWM action potentials, and in pharyngeal muscle, measured in simultaneous optical and sharp electrode recordings, MacQ-mCitrine showed approximately 20% ΔF/F per 100 mV. All sensors reported differences in muscle depolarization induced by a voltage-gated Ca2+-channel mutant. Optogenetically evoked de- or hyperpolarization of motor neurons increased or eliminated action potential activity and caused a rise or drop in BWM sensor fluorescence. Finally, we analyzed voltage dynamics across the entire pharynx, showing uniform depolarization but compartmentalized repolarization of anterior and posterior parts. Our work establishes all-optical, noninvasive electrophysiology in live, intact C. elegans.
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27
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Nicoletti M, Loppini A, Chiodo L, Folli V, Ruocco G, Filippi S. Biophysical modeling of C. elegans neurons: Single ion currents and whole-cell dynamics of AWCon and RMD. PLoS One 2019; 14:e0218738. [PMID: 31260485 PMCID: PMC6602206 DOI: 10.1371/journal.pone.0218738] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/07/2019] [Indexed: 01/28/2023] Open
Abstract
C. elegans neuronal system constitutes the ideal framework for studying simple, yet realistic, neuronal activity, since the whole nervous system is fully characterized with respect to the exact number of neurons and the neuronal connections. Most recent efforts are devoted to investigate and clarify the signal processing and functional connectivity, which are at the basis of sensing mechanisms, signal transmission, and motor control. In this framework, a refined modelof whole neuron dynamics constitutes a key ingredient to describe the electrophysiological processes, both at thecellular and at the network scale. In this work, we present Hodgkin-Huxley-based models of ion channels dynamics black, built on data available both from C. elegans and from other organisms, expressing homologous channels. We combine these channel models to simulate the electrical activity oftwo among the most studied neurons in C. elegans, which display prototypical dynamics of neuronal activation, the chemosensory AWCON and the motor neuron RMD. Our model properly describes the regenerative responses of the two cells. We analyze in detail the role of ion currents, both in wild type and in in silico knockout neurons. Moreover, we specifically investigate the behavior of RMD, identifying a heterogeneous dynamical response which includes bistable regimes and sustained oscillations. We are able to assess the critical role of T-type calcium currents, carried by CCA-1 channels, and leakage currents in the regulation of RMD response. Overall, our results provide new insights in the activity of key C. elegans neurons. The developed mathematical framework constitute a basis for single-cell and neuronal networks analyses, opening new scenarios in the in silico modeling of C. elegans neuronal system.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano Science CLNS@Sapienza, Istituto Italiano di Tecnologia - IIT, Rome, Italy
| | | | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
| | - Viola Folli
- Center for Life Nano Science CLNS@Sapienza, Istituto Italiano di Tecnologia - IIT, Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano Science CLNS@Sapienza, Istituto Italiano di Tecnologia - IIT, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
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28
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Kozlova AA, Lotfi M, Okkema PG. Cross Talk with the GAR-3 Receptor Contributes to Feeding Defects in Caenorhabditis elegans eat-2 Mutants. Genetics 2019; 212:231-243. [PMID: 30898771 PMCID: PMC6499512 DOI: 10.1534/genetics.119.302053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 03/14/2019] [Indexed: 02/02/2023] Open
Abstract
Precise signaling at the neuromuscular junction (NMJ) is essential for proper muscle contraction. In the Caenorhabditis elegans pharynx, acetylcholine (ACh) released from the MC and M4 motor neurons stimulates two different types of contractions in adjacent muscle cells, termed pumping and isthmus peristalsis. MC stimulates rapid pumping through the nicotinic ACh receptor EAT-2, which is tightly localized at the MC NMJ, and eat-2 mutants exhibit a slow pump rate. Surprisingly, we found that eat-2 mutants also hyperstimulated peristaltic contractions, and that they were characterized by increased and prolonged Ca2+ transients in the isthmus muscles. This hyperstimulation depends on cross talk with the GAR-3 muscarinic ACh receptor as gar-3 mutation specifically suppressed the prolonged contraction and increased Ca2+ observed in eat-2 mutant peristalses. Similar GAR-3-dependent hyperstimulation was also observed in mutants lacking the ace-3 acetylcholinesterase, and we suggest that NMJ defects in eat-2 and ace-3 mutants result in ACh stimulation of extrasynaptic GAR-3 receptors in isthmus muscles. gar-3 mutation also suppressed slow larval growth and prolonged life span phenotypes that result from dietary restriction in eat-2 mutants, indicating that cross talk with the GAR-3 receptor has a long-term impact on feeding behavior and eat-2 mutant phenotypes.
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Affiliation(s)
- Alena A Kozlova
- Department of Biological Sciences, University of Illinois at Chicago, Illinois 60607
| | - Michelle Lotfi
- Department of Biological Sciences, University of Illinois at Chicago, Illinois 60607
| | - Peter G Okkema
- Department of Biological Sciences, University of Illinois at Chicago, Illinois 60607
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29
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Shindou T, Ochi-Shindou M, Murayama T, Saita EI, Momohara Y, Wickens JR, Maruyama IN. Active propagation of dendritic electrical signals in C. elegans. Sci Rep 2019; 9:3430. [PMID: 30837592 PMCID: PMC6401061 DOI: 10.1038/s41598-019-40158-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 02/11/2019] [Indexed: 11/09/2022] Open
Abstract
Active propagation of electrical signals in C. elegans neurons requires ion channels capable of regenerating membrane potentials. Here we report regenerative depolarization of a major gustatory sensory neuron, ASEL. Whole-cell patch-clamp recordings in vivo showed supralinear depolarization of ASEL upon current injection. Furthermore, stimulation of animal's nose with NaCl evoked all-or-none membrane depolarization in ASEL. Mutant analysis showed that EGL-19, the α1 subunit of L-type voltage-gated Ca2+ channels, is essential for regenerative depolarization of ASEL. ASEL-specific knock-down of EGL-19 by RNAi demonstrated that EGL-19 functions in C. elegans chemotaxis along an NaCl gradient. These results demonstrate that a natural substance induces regenerative all-or-none electrical signals in dendrites, and that these signals are essential for activation of sensory neurons for chemotaxis. As in other vertebrate and invertebrate nervous systems, active information processing in dendrites occurs in C. elegans, and is necessary for adaptive behavior.
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Affiliation(s)
- Tomomi Shindou
- Neurobiology Research Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Mayumi Ochi-Shindou
- Neurobiology Research Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Takashi Murayama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Ei-Ichiro Saita
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Yuto Momohara
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Jeffery R Wickens
- Neurobiology Research Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Ichiro N Maruyama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan.
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30
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García-Casas P, Arias-Del-Val J, Alvarez-Illera P, Wojnicz A, de Los Ríos C, Fonteriz RI, Montero M, Alvarez J. The Neuroprotector Benzothiazepine CGP37157 Extends Lifespan in C. elegans Worms. Front Aging Neurosci 2019; 10:440. [PMID: 30705628 PMCID: PMC6344432 DOI: 10.3389/fnagi.2018.00440] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 12/31/2018] [Indexed: 11/14/2022] Open
Abstract
The benzothiazepine CGP37157 has shown neuroprotective effects in several in vitro models of excitotoxicity involving dysregulation of intracellular Ca2+ homeostasis. Although its mechanism of neuroprotection is unclear, it is probably related with some of its effects on Ca2+ homeostasis. CGP37157 is a well-known inhibitor of the mitochondrial Na+/Ca2+ exchanger (mNCX). However, it is not very specific and also blocks several other Ca2+ channels and transporters, including voltage-gated Ca2+ channels, plasma membrane Na+/Ca2+ exchanger and the Ca2+ homeostasis modulator 1 channel (CALHM1). In the present work, we have studied if CGP37157 could also induce changes in life expectancy. We now report that CGP37157 extends C. elegans lifespan by 10%–15% with a bell-shaped concentration-response, with high concentrations producing no effect. The effect was even larger (25% increase in life expectancy) in worms fed with heat-inactivated bacteria. The worm CGP37157 concentration producing maximum effect was measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and was close to the IC50 for inhibition of the Na+/Ca2+ exchanger. CGP37157 also extended the lifespan in eat-2 mutants (a model for caloric restriction), suggesting that caloric restriction is not involved in the mechanism of lifespan extension. Actually, CGP37157 produced no effect in mutants of the TOR pathway (daf15/unc24) or the insulin/insulin-like growth factor-1 (IGF-1) pathway (daf-2), indicating that the effect involves these pathways. Moreover, CGP37157 was also ineffective in nuo-6 mutants, which have a defect in the mitochondrial respiratory chain complex I. Since it has been described that neuroprotection by this compound in cell cultures is abolished by mitochondrial inhibitors, this suggests that life extension in C. elegans and neuroprotection in cell cultures may share a similar mechanism involving mitochondria.
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Affiliation(s)
- Paloma García-Casas
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
| | - Jessica Arias-Del-Val
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
| | - Pilar Alvarez-Illera
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
| | - Aneta Wojnicz
- Department of Clinical Pharmacology, Instituto Teófilo Hernando, Instituto de Investigación Sanitaria la Princesa (IP), Hospital Universitario de la Princesa, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Cristobal de Los Ríos
- Department of Clinical Pharmacology, Instituto Teófilo Hernando, Instituto de Investigación Sanitaria la Princesa (IP), Hospital Universitario de la Princesa, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Rosalba I Fonteriz
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
| | - Mayte Montero
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
| | - Javier Alvarez
- Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and CSIC, Valladolid, Spain
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31
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C. elegans AWA Olfactory Neurons Fire Calcium-Mediated All-or-None Action Potentials. Cell 2018; 175:57-70.e17. [PMID: 30220455 DOI: 10.1016/j.cell.2018.08.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/24/2018] [Accepted: 08/09/2018] [Indexed: 12/25/2022]
Abstract
Neurons in Caenorhabditis elegans and other nematodes have been thought to lack classical action potentials. Unexpectedly, we observe membrane potential spikes with defining characteristics of action potentials in C. elegans AWA olfactory neurons recorded under current-clamp conditions. Ion substitution experiments, mutant analysis, pharmacology, and modeling indicate that AWA fires calcium spikes, which are initiated by EGL-19 voltage-gated CaV1 calcium channels and terminated by SHK-1 Shaker-type potassium channels. AWA action potentials result in characteristic signals in calcium imaging experiments. These calcium signals are also observed when intact animals are exposed to odors, suggesting that natural odor stimuli induce AWA spiking. The stimuli that elicit action potentials match AWA's specialized function in climbing odor gradients. Our results provide evidence that C. elegans neurons can encode information through regenerative all-or-none action potentials, expand the computational repertoire of its nervous system, and inform future modeling of its neural coding and network dynamics.
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32
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Diomede L, Romeo M, Rognoni P, Beeg M, Foray C, Ghibaudi E, Palladini G, Cherny RA, Verga L, Capello GL, Perfetti V, Fiordaliso F, Merlini G, Salmona M. Cardiac Light Chain Amyloidosis: The Role of Metal Ions in Oxidative Stress and Mitochondrial Damage. Antioxid Redox Signal 2017; 27:567-582. [PMID: 28132512 PMCID: PMC5567464 DOI: 10.1089/ars.2016.6848] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIMS The knowledge of the mechanism underlying the cardiac damage in immunoglobulin light chain (LC) amyloidosis (AL) is essential to develop novel therapies and improve patients' outcome. Although an active role of reactive oxygen species (ROS) in LC-induced cardiotoxicity has already been envisaged, the actual mechanisms behind their generation remain elusive. This study was aimed at further dissecting the action of ROS generated by cardiotoxic LC in vivo and investigating whether transition metal ions are involved in this process. In the absence of reliable vertebrate model of AL, we used the nematode Caenorhabditis elegans, whose pharynx is an "ancestral heart." RESULTS LC purified from patients with severe cardiac involvement intrinsically generated high levels of ROS and when administered to C. elegans induced ROS production, activation of the DAF-16/forkhead transcription factor (FOXO) pathway, and expression of proteins involved in stress resistance and survival. Profound functional and structural ROS-mediated mitochondrial damage, similar to that observed in amyloid-affected hearts from AL patients, was observed. All these effects were entirely dependent on the presence of metal ions since addition of metal chelator or metal-binding 8-hydroxyquinoline compounds (chelex, PBT2, and clioquinol) permanently blocked the ROS production and prevented the cardiotoxic effects of amyloid LC. Innovation and Conclusion: Our findings identify the key role of metal ions in driving the ROS-mediated toxic effects of LC. This is a novel conceptual advance that paves the way for new pharmacological strategies aimed at not only counteracting but also totally inhibiting the vicious cycle of redox damage. Antioxid. Redox Signal. 27, 567-582.
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Affiliation(s)
- Luisa Diomede
- 1 Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
| | - Margherita Romeo
- 1 Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
| | - Paola Rognoni
- 2 Amyloid Research and Treatment Center , Foundation IRCCS Policlinico San Matteo, Pavia, Italy
| | - Marten Beeg
- 1 Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
| | - Claudia Foray
- 3 Bio-imaging Unit, Department of Cardiovascular Research, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
| | - Elena Ghibaudi
- 4 Department of Chemistry, University of Turin , Turin, Italy
| | - Giovanni Palladini
- 2 Amyloid Research and Treatment Center , Foundation IRCCS Policlinico San Matteo, Pavia, Italy .,5 Department of Molecular Medicine, University of Pavia , Pavia, Italy
| | - Robert A Cherny
- 6 The Florey Institute of Neuroscience and Mental Health, The University of Melbourne , Royal Pde, Parkville, Australia .,7 Prana Biotechnology Ltd. , Parkville, Australia
| | - Laura Verga
- 8 Pathologic Unit, Foundation IRCCS Policlinico San Matteo , Pavia, Italy
| | - Gian Luca Capello
- 8 Pathologic Unit, Foundation IRCCS Policlinico San Matteo , Pavia, Italy
| | - Vittorio Perfetti
- 9 Medical Oncology Unit, Foundation IRCCS Policlinico San Matteo , Pavia, Italy
| | - Fabio Fiordaliso
- 3 Bio-imaging Unit, Department of Cardiovascular Research, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
| | - Giampaolo Merlini
- 2 Amyloid Research and Treatment Center , Foundation IRCCS Policlinico San Matteo, Pavia, Italy .,5 Department of Molecular Medicine, University of Pavia , Pavia, Italy
| | - Mario Salmona
- 1 Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri ," Milan, Italy
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Zeng R, Yu X, Tan X, Ye S, Ding Z. Deltamethrin affects the expression of voltage-gated calcium channel α1 subunits and the locomotion, egg-laying, foraging behavior of Caenorhabditis elegans. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 138:84-90. [PMID: 28456310 DOI: 10.1016/j.pestbp.2017.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 02/13/2017] [Accepted: 03/05/2017] [Indexed: 06/07/2023]
Abstract
Deltamethrin belongs to the class of synthetic pyrethroids, which are being widely used as insecticides in agricultural practices. Voltage-gated sodium channels (VGSCs) are the primary targets of these chemicals for toxicity to insects. Caenorhabditis elegans (C. elegans) does not have VGSCs but is susceptible to deltamethrin. Recent findings have suggested that pyrethroids can affect voltage-gated calcium channels (VGCCs). However, it remains elusive whether deltamethrin induces toxicity to C. elegans via modulating the activity of VGCCs. To identify the potential target of deltamethrin, we exposed C. elegans to different concentrations of deltamethrin and Ca2+ channel blockers for different times, characterized the behavioral toxicity of deltamethrin on C. elegans, and determined the expression of egl-19, unc-2, and cca-1, which encode the α1-subunit of the L-, R/N/P/Q-, and T-type VGCC, respectively. We found that deltamethrin inhibited the locomotion, egg-laying and foraging ability of C. elegans in a concentration dependent manner. We also showed that body length of worms on agar plates containing 200mgL-1 deltamethrin for 12h was not significantly different from controls, whereas the cholinesterase inhibitor carbofuran caused hypercontraction which is a characteristic of organophosphates and carbamates, suggesting that deltamethrin's mode of action is distinct from those nematicides. In addition, unc-2 was significantly up-regulated following 0.05mgL-1 deltamethrin exposure for 24h; while egl-19 and cca-1 were significantly up-regulated following 5 and 50mgL-1 deltamethrin exposure for 24h. Further tests of worms' sensitivity and expression of three α1-subunits of VGCC to Ca2+ channel blockers indicate that deltamethrin may induce toxic behavior C. elegans via modulation of the expression of the α1-subunits of VGCC. This study provides insights into the linkage between deltamethrin-induced toxic behavior and the regulation of α1-subunits of VGCC in C. elegans.
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Affiliation(s)
- Rune Zeng
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China
| | - Xing Yu
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China
| | - Xing Tan
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China
| | - Shan Ye
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Disease and Insect Pests, Changsha 410128, China
| | - Zhong Ding
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Disease and Insect Pests, Changsha 410128, China.
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Zang KE, Ho E, Ringstad N. Inhibitory peptidergic modulation of C. elegans serotonin neurons is gated by T-type calcium channels. eLife 2017; 6. [PMID: 28165324 PMCID: PMC5330680 DOI: 10.7554/elife.22771] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/06/2017] [Indexed: 12/30/2022] Open
Abstract
Serotonin is an evolutionarily ancient molecule that functions in generating and modulating many behavioral states. Although much is known about how serotonin acts on its cellular targets, how serotonin release is regulated in vivo remains poorly understood. In the nematode C. elegans, serotonin neurons that drive female reproductive behavior are directly modulated by inhibitory neuropeptides. Here, we report the isolation of mutants in which inhibitory neuropeptides fail to properly modulate serotonin neurons and the behavior they mediate. The corresponding mutations affect the T-type calcium channel CCA-1 and symmetrically re-tune its voltage-dependencies of activation and inactivation towards more hyperpolarized potentials. This shift in voltage dependency strongly and specifically bypasses the behavioral and cell physiological effects of peptidergic inhibition on serotonin neurons. Our results indicate that T-type calcium channels are critical regulators of a C. elegans serotonergic circuit and demonstrate a mechanism in which T-type channels functionally gate inhibitory modulation in vivo.
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Affiliation(s)
- Kara E Zang
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
| | - Elver Ho
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
| | - Niels Ringstad
- Skirball Institute for Biomolecular Medicine, The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Department of Cell Biology, NYU Langone School of Medicine, New York, United States
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35
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Alvarez-Illera P, Sanchez-Blanco A, Lopez-Burillo S, Fonteriz RI, Alvarez J, Montero M. Long-term monitoring of Ca2+ dynamics in C. elegans pharynx: an in vivo energy balance sensor. Oncotarget 2016; 7:67732-67747. [PMID: 27661127 PMCID: PMC5356515 DOI: 10.18632/oncotarget.12177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 09/16/2016] [Indexed: 11/25/2022] Open
Abstract
Ca2+ is a key signal transducer for muscle contraction. Continuous in vivo monitoring of intracellular Ca2+-dynamics in C. elegans pharynx muscle revealed surprisingly complex Ca2+ patterns. Despite the age-dependent decline of pharynx pumping, we observed unaltered fast Ca2+ oscillations both in young and old worms. In addition, sporadic prolonged Ca2+ increases lasting many seconds or minutes were often observed in between periods of fast Ca2+ oscillations. We attribute them to the inhibition of ATP-dependent Ca2+-pumps upon energy depletion. Accordingly, food deprivation largely augmented the frequency of prolonged [Ca2+] increases. However, paradoxically, prolonged [Ca2+] increases were more frequently observed in young worms than in older ones, and less frequently observed in energy-deficient mitochondrial respiratory chain nuo-6 mutants than in wild-type controls. We hypothesize that young animals are more susceptible to energy depletion due to their faster energy consumption rate, while nuo-6 mutants may keep better the energy balance by slowing energy consumption. Our data therefore suggest that the metabolic state of the pharynx during feeding stimulation depends mainly on the delicate balance between the instant rates of energy production and consumption. Thus, in vivo monitoring of muscle Ca2+ dynamics can be used as a novel tool to study cellular energy availability.
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Affiliation(s)
- Pilar Alvarez-Illera
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain
| | | | - Silvia Lopez-Burillo
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain
| | - Rosalba I. Fonteriz
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain
| | - Javier Alvarez
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain
| | - Mayte Montero
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain
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36
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Trojanowski NF, Raizen DM, Fang-Yen C. Pharyngeal pumping in Caenorhabditis elegans depends on tonic and phasic signaling from the nervous system. Sci Rep 2016; 6:22940. [PMID: 26976078 PMCID: PMC4791602 DOI: 10.1038/srep22940] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/23/2016] [Indexed: 02/02/2023] Open
Abstract
Rhythmic movements are ubiquitous in animal locomotion, feeding, and circulatory systems. In some systems, the muscle itself generates rhythmic contractions. In others, rhythms are generated by the nervous system or by interactions between the nervous system and muscles. In the nematode Caenorhabditis elegans, feeding occurs via rhythmic contractions (pumping) of the pharynx, a neuromuscular feeding organ. Here, we use pharmacology, optogenetics, genetics, and electrophysiology to investigate the roles of the nervous system and muscle in generating pharyngeal pumping. Hyperpolarization of the nervous system using a histamine-gated chloride channel abolishes pumping, and optogenetic stimulation of pharyngeal muscle in these animals causes abnormal contractions, demonstrating that normal pumping requires nervous system function. In mutants that pump slowly due to defective nervous system function, tonic muscle stimulation causes rapid pumping, suggesting tonic neurotransmitter release may regulate pumping. However, tonic cholinergic motor neuron stimulation, but not tonic muscle stimulation, triggers pumps that electrophysiologically resemble typical rapid pumps. This suggests that pharyngeal cholinergic motor neurons are normally rhythmically, and not tonically active. These results demonstrate that the pharynx generates a myogenic rhythm in the presence of tonically released acetylcholine, and suggest that the pharyngeal nervous system entrains contraction rate and timing through phasic neurotransmitter release.
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Affiliation(s)
- Nicholas F Trojanowski
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA, USA.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, 19104 PA, USA.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA, USA
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA, USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, 19104 PA, USA.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA, USA
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Abstract
Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed quiescence (DTQ) occurs during larval transitions, and stress-induced quiescence (SIQ) occurs in response to exposure to cellular stressors. Behaviorally, DTQ and SIQ appear identical. Here, we use optogenetic manipulations of neuronal and muscular activity, pharmacology, and genetic perturbations to uncover circuit and molecular mechanisms of DTQ and SIQ. We find that locomotion quiescence induced by DTQ- and SIQ-associated neuropeptides occurs via their action on the nervous system, although their neuronal target(s) and/or molecular mechanisms likely differ. Feeding quiescence during DTQ results from a loss of pharyngeal muscle excitability, whereas feeding quiescence during SIQ results from a loss of excitability in the nervous system. Together these results indicate that, as in mammals, quiescence is subserved by different mechanisms during distinct sleep-like states in C. elegans.
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38
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Schüler C, Fischer E, Shaltiel L, Steuer Costa W, Gottschalk A. Arrhythmogenic effects of mutated L-type Ca 2+-channels on an optogenetically paced muscular pump in Caenorhabditis elegans. Sci Rep 2015; 5:14427. [PMID: 26399900 PMCID: PMC4585839 DOI: 10.1038/srep14427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/28/2015] [Indexed: 01/23/2023] Open
Abstract
Cardiac arrhythmias are often associated with mutations in ion channels or other proteins. To enable drug development for distinct arrhythmias, model systems are required that allow implementing patient-specific mutations. We assessed a muscular pump in Caenorhabditis elegans. The pharynx utilizes homologues of most of the ion channels, pumps and transporters defining human cardiac physiology. To yield precise rhythmicity, we optically paced the pharynx using channelrhodopsin-2. We assessed pharynx pumping by extracellular recordings (electropharyngeograms—EPGs), and by a novel video-microscopy based method we developed, which allows analyzing multiple animals simultaneously. Mutations in the L-type VGCC (voltage-gated Ca2+-channel) EGL-19 caused prolonged pump duration, as found for analogous mutations in the Cav1.2 channel, associated with long QT syndrome. egl-19 mutations affected ability to pump at high frequency and induced arrhythmicity. The pharyngeal neurons did not influence these effects. We tested whether drugs could ameliorate arrhythmia in the optogenetically paced pharynx. The dihydropyridine analog Nemadipine A prolonged pump duration in wild type, and reduced or prolonged pump duration of distinct egl-19 alleles, thus indicating allele-specific effects. In sum, our model may allow screening of drug candidates affecting specific VGCCs mutations, and permit to better understand the effects of distinct mutations on a macroscopic level.
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Affiliation(s)
- Christina Schüler
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
| | - Elisabeth Fischer
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
| | - Lior Shaltiel
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany
| | - Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany.,Institute of Biochemistry, Goethe University, Max von Laue Strasse 9, D-60438 Frankfurt, Germany.,Cluster of Excellence Frankfurt-Macromolecular Complexes, Goethe University, Max von Laue Strasse 15, D-60438 Frankfurt, Germany
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39
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Lainé V, Ségor JR, Zhan H, Bessereau JL, Jospin M. Hyperactivation of L-type voltage-gated Ca2+ channels in Caenorhabditis elegans striated muscle can result from point mutations in the IS6 or the IIIS4 segment of the α1 subunit. ACTA ACUST UNITED AC 2014; 217:3805-14. [PMID: 25214488 DOI: 10.1242/jeb.106732] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Several human diseases, including hypokalemic periodic paralysis and Timothy syndrome, are caused by mutations in voltage-gated calcium channels. The effects of these mutations are not always well understood, partially because of difficulties in expressing these channels in heterologous systems. The use of Caenorhabditis elegans could be an alternative approach to determine the effects of mutations on voltage-gated calcium channel function because all the main types of voltage-gated calcium channels are found in C. elegans, a large panel of mutations already exists and efficient genetic tools are available to engineer customized mutations in any gene. In this study, we characterize the effects of two gain-of-function mutations in egl-19, which encodes the L-type calcium channel α1 subunit. One of these mutations, ad695, leads to the replacement of a hydrophobic residue in the IIIS4 segment. The other mutation, n2368, changes a conserved glycine of IS6 segment; this mutation has been identified in patients with Timothy syndrome. We show that both egl-19 (gain-of-function) mutants have defects in locomotion and morphology that are linked to higher muscle tone. Using in situ electrophysiological approaches in striated muscle cells, we provide evidence that this high muscle tone is due to a shift of the voltage dependency towards negative potentials, associated with a decrease of the inactivation rate of the L-type Ca(2+) current. Moreover, we show that the maximal conductance of the Ca(2+) current is decreased in the strongest mutant egl-19(n2368), and that this decrease is correlated with a mislocalization of the channel.
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Affiliation(s)
- Viviane Lainé
- CNRS, UMR 5534, Université Lyon 1, Villeurbanne, F-69622, France
| | - Jean Rony Ségor
- CNRS, UMR 5534, Université Lyon 1, Villeurbanne, F-69622, France
| | - Hong Zhan
- CNRS, UMR 5534, Université Lyon 1, Villeurbanne, F-69622, France
| | | | - Maelle Jospin
- CNRS, UMR 5534, Université Lyon 1, Villeurbanne, F-69622, France
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40
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Functional evolution of Erg potassium channel gating reveals an ancient origin for IKr. Proc Natl Acad Sci U S A 2014; 111:5712-7. [PMID: 24706772 DOI: 10.1073/pnas.1321716111] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mammalian Ether-a-go-go related gene (Erg) family voltage-gated K(+) channels possess an unusual gating phenotype that specializes them for a role in delayed repolarization. Mammalian Erg currents rectify during depolarization due to rapid, voltage-dependent inactivation, but rebound during repolarization due to a combination of rapid recovery from inactivation and slow deactivation. This is exemplified by the mammalian Erg1 channel, which is responsible for IKr, a current that repolarizes cardiac action potential plateaus. The Drosophila Erg channel does not inactivate and closes rapidly upon repolarization. The dramatically different properties observed in mammalian and Drosophila Erg homologs bring into question the evolutionary origins of distinct Erg K(+) channel functions. Erg channels are highly conserved in eumetazoans and first evolved in a common ancestor of the placozoans, cnidarians, and bilaterians. To address the ancestral function of Erg channels, we identified and characterized Erg channel paralogs in the sea anemone Nematostella vectensis. N. vectensis Erg1 (NvErg1) is highly conserved with respect to bilaterian homologs and shares the IKr-like gating phenotype with mammalian Erg channels. Thus, the IKr phenotype predates the divergence of cnidarians and bilaterians. NvErg4 and Caenorhabditis elegans Erg (unc-103) share the divergent Drosophila Erg gating phenotype. Phylogenetic and sequence analysis surprisingly indicates that this alternate gating phenotype arose independently in protosomes and cnidarians. Conversion from an ancestral IKr-like gating phenotype to a Drosophila Erg-like phenotype correlates with loss of the cytoplasmic Ether-a-go-go domain. This domain is required for slow deactivation in mammalian Erg1 channels, and thus its loss may partially explain the change in gating phenotype.
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Dillon J, Andrianakis I, Mould R, Ient B, Liu W, James C, O'Connor V, Holden-Dye L. Distinct molecular targets including SLO-1 and gap junctions are engaged across a continuum of ethanol concentrations in Caenorhabditis elegans. FASEB J 2013; 27:4266-78. [PMID: 23882127 DOI: 10.1096/fj.11-189340] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ethanol (alcohol) interacts with diverse molecular effectors across a range of concentrations in the brain, eliciting intoxication through to sedation. Invertebrate models including the nematode worm Caenorhabditis elegans have been deployed for molecular genetic studies to inform on key components of these alcohol signaling pathways. C. elegans studies have typically employed external dosing with high (>250 mM) ethanol concentrations: A careful analysis of responses to low concentrations is lacking. Using the C. elegans pharyngeal system as a paradigm, we report a previously uncharacterized continuum of cellular and behavioral responses to ethanol from low (10 mM) to high (300 mM) concentrations. The complexity of these responses indicates that the pleiotropic action of ethanol observed in mammalian brain is conserved in this invertebrate model. We investigated two candidate ethanol effectors, the calcium-activated K(+) channel SLO-1 and gap junctions, and show that they contribute to, but are not sole determinants of, the low- and high-concentration effects, respectively. Notably, this study shows cellular and whole organismal behavioral responses to ethanol in C. elegans that directly equate to intoxicating through to supralethal blood alcohol concentrations in humans and provides an important benchmark for interpretation of paradigms that seek to inform on human alcohol use disorders.
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Affiliation(s)
- James Dillon
- 1Current address: Institute of Digital Healthcare, Warwick Manufacturing Group, University of Warwick, Coventry CV4 7AL, UK
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Smith MA, Zhang Y, Polli JR, Wu H, Zhang B, Xiao P, Farwell MA, Pan X. Impacts of chronic low-level nicotine exposure on Caenorhabditis elegans reproduction: identification of novel gene targets. Reprod Toxicol 2013; 40:69-75. [PMID: 23735997 DOI: 10.1016/j.reprotox.2013.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/25/2013] [Accepted: 05/24/2013] [Indexed: 12/17/2022]
Abstract
Effects and mechanisms of chronic exposure to low levels of nicotine is an area fundamentally important however less investigated. We employed the model organism Caenorhabditis elegans to investigate potential impacts of chronic (24h) and low nicotine exposure (6.17-194.5 μM) on stimulus-response, reproduction, and gene expressions. Nicotine significantly affects the organism's response to touch stimulus (p=0.031), which follows a dose-dependent pattern. Chronic nicotine exposure promotes early egg-laying events and slightly increased egg productions during the first 72 h of adulthood. The expressions of 10 (egl-10, egl-44, hlh-14, ric-3, unc-103, unc-50, unc-68, sod-1, oxi-1, and old-1) out of 18 selected genes were affected significantly. Other tested genes were cat-4, egl-19, egl-47, egl-5, lin-39, unc-43, pink-1, and age-1. Changes in gene expression were more evident at low dosages than at relatively high levels. Genes implicated in reproduction, cholinergic signaling, and stress response were regulated by nicotine, suggesting widespread physiological impacts of nicotine.
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Affiliation(s)
- Michael A Smith
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
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Taiakina V, Boone AN, Fux J, Senatore A, Weber-Adrian D, Guillemette JG, Spafford JD. The calmodulin-binding, short linear motif, NSCaTE is conserved in L-type channel ancestors of vertebrate Cav1.2 and Cav1.3 channels. PLoS One 2013; 8:e61765. [PMID: 23626724 PMCID: PMC3634016 DOI: 10.1371/journal.pone.0061765] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/11/2013] [Indexed: 01/21/2023] Open
Abstract
NSCaTE is a short linear motif of (xWxxx(I or L)xxxx), composed of residues with a high helix-forming propensity within a mostly disordered N-terminus that is conserved in L-type calcium channels from protostome invertebrates to humans. NSCaTE is an optional, lower affinity and calcium-sensitive binding site for calmodulin (CaM) which competes for CaM binding with a more ancient, C-terminal IQ domain on L-type channels. CaM bound to N- and C- terminal tails serve as dual detectors to changing intracellular Ca2+ concentrations, promoting calcium-dependent inactivation of L-type calcium channels. NSCaTE is absent in some arthropod species, and is also lacking in vertebrate L-type isoforms, Cav1.1 and Cav1.4 channels. The pervasiveness of a methionine just downstream from NSCaTE suggests that L-type channels could generate alternative N-termini lacking NSCaTE through the choice of translational start sites. Long N-terminus with an NSCaTE motif in L-type calcium channel homolog LCav1 from pond snail Lymnaea stagnalis has a faster calcium-dependent inactivation than a shortened N-termini lacking NSCaTE. NSCaTE effects are present in low concentrations of internal buffer (0.5 mM EGTA), but disappears in high buffer conditions (10 mM EGTA). Snail and mammalian NSCaTE have an alpha-helical propensity upon binding Ca2+-CaM and can saturate both CaM N-terminal and C-terminal domains in the absence of a competing IQ motif. NSCaTE evolved in ancestors of the first animals with internal organs for promoting a more rapid, calcium-sensitive inactivation of L-type channels.
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Affiliation(s)
| | | | - Julia Fux
- Department of Biology, University of Waterloo, Waterloo, Canada
| | | | | | | | - J. David Spafford
- Department of Biology, University of Waterloo, Waterloo, Canada
- * E-mail:
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Swiatkowski P, Sesti F. Delayed pharyngeal repolarization promotes abnormal calcium buildup in aging muscle. Biochem Biophys Res Commun 2013; 433:354-7. [PMID: 23510998 DOI: 10.1016/j.bbrc.2013.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 03/08/2013] [Indexed: 11/28/2022]
Abstract
In the pharynx of Caenorhabditis elegans, the accessory subunit MPS-4, homolog to human KCNE1, forms a complex with K(+) channel EXP-2 that terminates the action potential. An aspartate residue critical for KCNE1 function, asp76, is conserved in MPS-4 (asp74). Here, we studied the effects of D74N-MPS-4 on the aging pharynx. Electrophysiological studies showed that D74N delays pharyngeal repolarization. Pharynxes of transgenic worms expressing D74N exhibited higher levels of intracellular calcium compared to normal pharynxes. Accordingly, loss of pharyngeal function was accelerated in aging D74N worms. The pharyngeal action potential resembles the action potential that controls the mechanical activity of human left ventricle. Hence, these findings argue that the hearts of patients affected by delayed repolarization, a condition known as long QT syndrome, may experience dysregulated calcium homeostasis.
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Affiliation(s)
- Przemyslaw Swiatkowski
- University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, Piscataway, NJ 08854, USA
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James SA, de Jonge MD, Howard DL, Bush AI, Paterson D, McColl G. Direct in vivo imaging of essential bioinorganics in Caenorhabditis elegans. Metallomics 2013; 5:627-35. [DOI: 10.1039/c3mt00010a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Hattori Y, Suzuki M, Soh Z, Kobayashi Y, Tsuji T. Modeling of the pharyngeal muscle in Caenorhabditis elegans based on FitzHugh-Nagumo equations. ARTIFICIAL LIFE AND ROBOTICS 2012. [DOI: 10.1007/s10015-012-0064-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Goodman MB, Lindsay TH, Lockery SR, Richmond JE. Electrophysiological methods for Caenorhabditis elegans neurobiology. Methods Cell Biol 2012; 107:409-36. [PMID: 22226532 DOI: 10.1016/b978-0-12-394620-1.00014-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Patch-clamp electrophysiology is a technique of choice for the biophysical analysis of the function of nerve, muscle, and synapse in Caenorhabditis elegans nematodes. Considerable technical progress has been made in C. elegans electrophysiology in the decade since the initial publication of this technique. Today, most, if not all, electrophysiological studies that can be done in larger animal preparations can also be done in C. elegans. This chapter has two main goals. The first is to present to a broad audience the many techniques available for patch-clamp analysis of neurons, muscles, and synapses in C. elegans. The second is to provide a methodological introduction to the techniques for patch clamping C. elegans neurons and body-wall muscles in vivo, including emerging methods for optogenetic stimulation coupled with postsynaptic recording. We also present samples of the cell-intrinsic and postsynaptic ionic currents that can be measured in C. elegans nerves and muscles.
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Affiliation(s)
- Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA
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49
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Stout RF, Parpura V. Voltage-gated calcium channel types in cultured C. elegans CEPsh glial cells. Cell Calcium 2011; 50:98-108. [PMID: 21684004 DOI: 10.1016/j.ceca.2011.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 05/12/2011] [Accepted: 05/15/2011] [Indexed: 12/20/2022]
Abstract
The four cephalic sensilla sheath (CEPsh) glial cells are important for development of the nervous system of Caenorhabditis elegans. Whether these invertebrate glia can generate intracellular Ca(2+) increases, a hallmark of mammalian glial cell excitability, is not known. To address this issue, we developed a transgenic worm with the specific co-expression of genetically encoded red fluorescent protein and green Ca(2+) sensor in CEPsh glial cells. This allowed us to identify CEPsh cells in culture and monitor their Ca(2+) dynamics. We show that CEPsh glial cells, in response to depolarization, generate various intracellular Ca(2+) increases mediated by voltage-gated Ca(2+) channels (VGCCs). Using a pharmacological approach, we find that the L-type is the preponderant VGCC type mediating Ca(2+) dynamics. Additionally, using a genetic approach we demonstrate that mutations in three known VGCC α(1)-subunit genes, cca-1, egl-19 and unc-2, can affect Ca(2+) dynamics of CEPsh glial cells. We suggest that VGCC-mediated Ca(2+) dynamics in the CEPsh glial cells are complex and display heterogeneity. These findings will aid understanding of how CEPsh glial cells contribute to the operation of the C. elegans nervous system.
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Affiliation(s)
- Randy F Stout
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy & Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA
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Lainé V, Frøkjær-Jensen C, Couchoux H, Jospin M. The alpha1 subunit EGL-19, the alpha2/delta subunit UNC-36, and the beta subunit CCB-1 underlie voltage-dependent calcium currents in Caenorhabditis elegans striated muscle. J Biol Chem 2011; 286:36180-7. [PMID: 21878625 DOI: 10.1074/jbc.m111.256149] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Voltage-gated calcium channels, which play key roles in many physiological processes, are composed of a pore-forming α1 subunit associated with up to three auxiliary subunits. In vertebrates, the role of auxiliary subunits has mostly been studied in heterologous systems, mainly because of the severe phenotypes of knock-out animals. The genetic model Caenorhabditis elegans has all main types of voltage-gated calcium channels and strong loss-of-function mutations in all pore-forming and auxiliary subunits; it is therefore a useful model to investigate the roles of auxiliary subunits in their native context. By recording calcium currents from channel and auxiliary subunit mutants, we molecularly dissected the voltage-dependent calcium currents in striated muscle of C. elegans. We show that EGL-19 is the only α1 subunit that carries calcium currents in muscle cells. We then demonstrate that the α2/δ subunit UNC-36 modulates the voltage dependence, the activation kinetics, and the conductance of calcium currents, whereas another α2/δ subunit TAG-180 has no effect. Finally, we characterize mutants of the two β subunits, CCB-1 and CCB-2. CCB-1 is necessary for viability, and voltage-dependent calcium currents are abolished in the absence of CCB-1 whereas CCB-2 does not affect currents. Altogether these results show that EGL-19, UNC-36, and CCB-1 underlie voltage-dependent calcium currents in C. elegans striated muscle.
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