1
|
Keilhoff G, Pinkernelle J, Fansa H. The Ryanodine receptor stabilizer S107 fails to support motor neuronal neuritogenesis in vitro. Tissue Cell 2021; 73:101625. [PMID: 34419737 DOI: 10.1016/j.tice.2021.101625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/15/2021] [Indexed: 11/30/2022]
Abstract
Calcium homeostasis is essential for neuronal cell survival/differentiation. Imbalance of the Ca2+ homeostasis due to excessive Ca2+ overload is essential for spinal cord injury (SCI). The overload resulted from Ca2+ flux across the plasma membrane and from internal Ca2+ store release (mitochondria, endoplasmic reticulum, ER). Inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) are involved in releasing Ca2+ from ER contributing to axonal degeneration following SCI. In turn, block of both receptors is axoprotective. The calstabin RyR subunit, stabilizing the channel in a state of reduced activity, prevents pathological Ca2+ release too. We investigated whether S107, a RyR-stabilizing compound (Rycal), is beneficial for survival and neuritogenesis of spinal cord motor neurons in vitro. We used a spinal cord slice model and the motor neuron-like NSC-34 cell line. Effects of S107 were tested by propidium iodide/fluorescein diacetate vital staining, mitotic index determination via BrdU-incorporation, and neurite sprouting parameters. Results showed that S107 (i) had no effect on gliosis resulting from slices preparation; (ii) had no effect on motor neuronal survival and proliferation; and (iii) impaired neurite sprouting, no matter whether it was a differentiation (NSC-34 cells) or regeneration (spinal cord slices) process. The results underline the need for a flexible Ca2+homeostasis provided by the ER for re-initiation of neuritogenesis.
Collapse
Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany.
| | - Josephine Pinkernelle
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany
| | - Hisham Fansa
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld, OWL-University, 33604, Bielefeld, Germany; Department of Plastic Surgery, and Breast Centre, Spital Zollikerberg, 8125, Zollikerberg, Switzerland
| |
Collapse
|
2
|
García-Hernández JL, Corchete LA, Marcos-Alcalde Í, Gómez-Puertas P, Fons C, Lazo PA. Pathogenic convergence of CNVs in genes functionally associated to a severe neuromotor developmental delay syndrome. Hum Genomics 2021; 15:11. [PMID: 33557955 PMCID: PMC7871650 DOI: 10.1186/s40246-021-00309-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/26/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Complex developmental encephalopathy syndromes might be the consequence of unknown genetic alterations that are likely to contribute to the full neurological phenotype as a consequence of pathogenic gene combinations. METHODS To identify the additional genetic contribution to the neurological phenotype, we studied as a test case a boy, with a KCNQ2 exon-7 partial duplication, by single-nucleotide polymorphism (SNP) microarray to detect copy-number variations (CNVs). RESULTS The proband presented a cerebral palsy like syndrome with a severe motor and developmental encephalopathy. The SNP array analysis detected in the proband several de novo CNVs, nine partial gene losses (LRRC55, PCDH9, NALCN, RYR3, ELAVL2, CDH13, ATP1A2, SLC17A5, ANO3), and two partial gene duplications (PCDH19, EFNA5). The biological functions of these genes are associated with ion channels such as calcium, chloride, sodium, and potassium with several membrane proteins implicated in neural cell-cell interactions, synaptic transmission, and axon guidance. Pathogenically, these functions can be associated to cerebral palsy, seizures, dystonia, epileptic crisis, and motor neuron dysfunction, all present in the patient. CONCLUSIONS Severe motor and developmental encephalopathy syndromes of unknown origin can be the result of a phenotypic convergence by combination of several genetic alterations in genes whose physiological function contributes to the neurological pathogenic mechanism.
Collapse
Affiliation(s)
- Juan L García-Hernández
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain
| | - Luis A Corchete
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain.,Network Center for Biomedical Research in Cancer (CIBERONC), Salamanca, Spain
| | - Íñigo Marcos-Alcalde
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.,Biosciences Research Institute, School of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Paulino Gómez-Puertas
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | - Carmen Fons
- Neurology Department, Hospital Sant Joan de Déu, Sant Joan de Déu Research Institute, Esplugues de Llobregat, Barcelona and CIBERER, Instituto de Salud Carlos III, Barcelona, Spain.
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain. .,Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain.
| |
Collapse
|
3
|
Kortus S, Srinivasan C, Forostyak O, Zapotocky M, Ueta Y, Sykova E, Chvatal A, Verkhratsky A, Dayanithi G. Sodium-calcium exchanger and R-type Ca(2+) channels mediate spontaneous [Ca(2+)]i oscillations in magnocellular neurones of the rat supraoptic nucleus. Cell Calcium 2016; 59:289-98. [PMID: 27052156 DOI: 10.1016/j.ceca.2016.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 03/30/2016] [Accepted: 03/30/2016] [Indexed: 10/22/2022]
Abstract
Isolated supraoptic neurones generate spontaneous [Ca(2+)]i oscillations in isolated conditions. Here we report in depth analysis of the contribution of plasmalemmal ion channels (Ca(2+), Na(+)), Na(+)/Ca(2+) exchanger (NCX), intracellular Ca(2+) release channels (InsP3Rs and RyRs), Ca(2+) storage organelles, plasma membrane Ca(2+) pump and intracellular signal transduction cascades into spontaneous Ca(2+) activity. While removal of extracellular Ca(2+) or incubation with non-specific voltage-gated Ca(2+) channel (VGCC) blocker Cd(2+) suppressed the oscillations, neither Ni(2+) nor TTA-P2, the T-type VGCC blockers, had an effect. Inhibitors of VGCC nicardipine, ω-conotoxin GVIA, ω-conotoxin MVIIC, ω-agatoxin IVA (for L-, N-, P and P/Q-type channels, respectively) did not affect [Ca(2+)]i oscillations. In contrast, a specific R-type VGCC blocker SNX-482 attenuated [Ca(2+)]i oscillations. Incubation with TTX had no effect, whereas removal of the extracellular Na(+) or application of an inhibitor of the reverse operation mode of Na(+)/Ca(2+) exchanger KB-R7943 blocked the oscillations. The mitochondrial uncoupler CCCP irreversibly blocked spontaneous [Ca(2+)]i activity. Exposure of neurones to Ca(2+) mobilisers (thapsigargin, cyclopiazonic acid, caffeine and ryanodine); 4-aminopyridine (A-type K(+) current blocker); phospholipase C and adenylyl cyclase pathways blockers U-73122, Rp-cAMP, SQ-22536 and H-89 had no effect. Oscillations were blocked by GABA, but not by glutamate, apamin or dynorphin. In conclusion, spontaneous oscillations in magnocellular neurones are mediated by a concerted action of R-type Ca(2+) channels and the NCX fluctuating between forward and reverse modes.
Collapse
Affiliation(s)
- Stepan Kortus
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Biophysics and Informatics, First Medical Faculty, Charles University in Prague, Salmovska 1, 12000 Prague, Czech Republic
| | - Chinnapaiyan Srinivasan
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Oksana Forostyak
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic
| | - Martin Zapotocky
- Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Biophysics and Informatics, First Medical Faculty, Charles University in Prague, Salmovska 1, 12000 Prague, Czech Republic
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Eva Sykova
- Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic; Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Alexandr Chvatal
- Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic; Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Alexei Verkhratsky
- University of Manchester, School of Biological Sciences, D.4417 Michael Smith Building, Oxford Road, M13 9PT Manchester, United Kingdom; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain; University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia.
| | - Govindan Dayanithi
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institut National de la Santé et de la Recherche Médicale, Unité de recherche U1198, Université Montpellier, 34095 Montpellier, France; Ecole Practique des Hautes Etudes, Sorbonne, 75014 Paris, France.
| |
Collapse
|
4
|
Kortus S, Srinivasan C, Forostyak O, Ueta Y, Sykova E, Chvatal A, Zapotocky M, Verkhratsky A, Dayanithi G. Physiology of spontaneous [Ca(2+)]i oscillations in the isolated vasopressin and oxytocin neurones of the rat supraoptic nucleus. Cell Calcium 2016; 59:280-8. [PMID: 27072326 PMCID: PMC4969632 DOI: 10.1016/j.ceca.2016.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 03/31/2016] [Accepted: 04/05/2016] [Indexed: 01/26/2023]
Abstract
Supraoptic fluorescent vasopressin (AVP-eGFP) and oxytocin (OT-mRFP1) neurones exhibit distinct spontaneous [Ca2+]i oscillations. Vasopressin triggers [Ca2+]i oscillations, intensifies existing oscillations, and exceptionally stops oscillations. Hyper- or hypo-osmotic stimuli have an intensifying or inhibitory effect on oscillations, respectively. Nearly 90% of neurones from 3 or 5-day-dehydrated rats exhibit oscillations. More than 80% of OT-mRFP1 neurones from 3 to 6-day-lactating rats are oscillatory vs. about 44% in virgins.
The magnocellular vasopressin (AVP) and oxytocin (OT) neurones exhibit specific electrophysiological behaviour, synthesise AVP and OT peptides and secrete them into the neurohypophysial system in response to various physiological stimulations. The activity of these neurones is regulated by the very same peptides released either somato-dendritically or when applied to supraoptic nucleus (SON) preparations in vitro. The AVP and OT, secreted somato-dendritically (i.e. in the SON proper) act through specific autoreceptors, induce distinct Ca2+ signals and regulate cellular events. Here, we demonstrate that about 70% of freshly isolated individual SON neurones from the adult non-transgenic or transgenic rats bearing AVP (AVP-eGFP) or OT (OT-mRFP1) markers, produce distinct spontaneous [Ca2+]i oscillations. In the neurones identified (through specific fluorescence), about 80% of AVP neurones and about 60% of OT neurones exhibited these oscillations. Exposure to AVP triggered [Ca2+]i oscillations in silent AVP neurones, or modified the oscillatory pattern in spontaneously active cells. Hyper- and hypo-osmotic stimuli (325 or 275 mOsmol/l) respectively intensified or inhibited spontaneous [Ca2+]i dynamics. In rats dehydrated for 3 or 5 days almost 90% of neurones displayed spontaneous [Ca2+]i oscillations. More than 80% of OT-mRFP1 neurones from 3 to 6-day-lactating rats were oscillatory vs. about 44% (OT-mRFP1 neurones) in virgins. Together, these results unveil for the first time that both AVP and OT neurones maintain, via Ca2+ signals, their remarkable intrinsic in vivo physiological properties in an isolated condition.
Collapse
Affiliation(s)
- Stepan Kortus
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Salmovska 1, 12000 Prague, Czech Republic
| | - Chinnapaiyan Srinivasan
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Oksana Forostyak
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Eva Sykova
- Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic; Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Alexandr Chvatal
- Department of Neuroscience, Charles University, Second Medical Faculty, V Uvalu 84, 15006 Prague, Czech Republic; Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Martin Zapotocky
- Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Salmovska 1, 12000 Prague, Czech Republic
| | - Alexei Verkhratsky
- University of Manchester, School of Biological Sciences, D.4417 Michael Smith Building, Oxford Road, M13 9PT Manchester, United Kingdom; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain; University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia.
| | - Govindan Dayanithi
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; Institut National de la Santé et de la Recherche Médicale, Unité de recherche U1198, Université Montpellier 2, 34095 Montpellier, France; Ecole Pratique des Hautes Etudes, Sorbonne, 75014 Paris, France.
| |
Collapse
|
5
|
Forostyak O, Butenko O, Anderova M, Forostyak S, Sykova E, Verkhratsky A, Dayanithi G. Specific profiles of ion channels and ionotropic receptors define adipose- and bone marrow derived stromal cells. Stem Cell Res 2016; 16:622-34. [PMID: 27062357 DOI: 10.1016/j.scr.2016.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 01/09/2023] Open
Abstract
Adherent, fibroblastic cells from different tissues are thought to contain subsets of tissue-specific stem/progenitor cells (often called mesenchymal stem cells). These cells display similar cell surface characteristics based on their fibroblastic nature, but also exhibit differences in molecular phenotype, growth rate, and their ability to differentiate into various cell phenotypes. The mechanisms underlying these differences remain poorly understood. We analyzed Ca(2+) signals and membrane properties in rat adipose-derived stromal cells (ADSCs) and bone marrow stromal cells (BMSCs) in basal conditions, and then following a switch into medium that contains factors known to modify their character. Modified ADSCs (mADSCs) expressed L-type Ca(2+) channels whereas both L- and P/Q- channels were operational in mBMSCs. Both mADSCs and mBMSCs possessed functional endoplasmic reticulum Ca(2+) stores, expressed ryanodine receptor-1 and -3, and exhibited spontaneous [Ca(2+)]i oscillations. The mBMSCs expressed P2X7 purinoceptors; the mADSCs expressed both P2X (but not P2X7) and P2Y (but not P2Y1) receptors. Both types of stromal cells exhibited [Ca(2+)]i responses to vasopressin (AVP) and expressed V1 type receptors. Functional oxytocin (OT) receptors were, in contrast, expressed only in modified ADSCs and BMSCs. AVP and OT-induced [Ca(2+)]i responses were dose-dependent and were blocked by their respective specific receptor antagonists. Electrophysiological data revealed that passive ion currents dominated the membrane conductance in ADSCs and BMSCs. Medium modification led to a significant shift in the reversal potential of passive currents from -40 to -50mV in cells in basal to -80mV in modified cells. Hence membrane conductance was mediated by non-selective channels in cells in basal conditions, whereas in modified medium conditions, it was associated with K(+)-selective channels. Our results indicate that modification of ADSCs and BMSCs by alteration in medium formulation is associated with significant changes in their Ca(2+) signaling and membrane properties.
Collapse
Affiliation(s)
- Oksana Forostyak
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic; Department of Neuroscience, Charles University, Second Faculty of Medicine, V Uvalu 84, Prague 15006, Czech Republic
| | - Olena Butenko
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic.
| | - Miroslava Anderova
- Department of Neuroscience, Charles University, Second Faculty of Medicine, V Uvalu 84, Prague 15006, Czech Republic; Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic
| | - Serhiy Forostyak
- Department of Neuroscience, Charles University, Second Faculty of Medicine, V Uvalu 84, Prague 15006, Czech Republic; Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic
| | - Eva Sykova
- Department of Neuroscience, Charles University, Second Faculty of Medicine, V Uvalu 84, Prague 15006, Czech Republic; Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic
| | - Alexei Verkhratsky
- University of Manchester, School of Biological Sciences, D.4417 Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia
| | - Govindan Dayanithi
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, Prague 14220, Czech Republic; Institut National de la Santé et de la Recherche Médicale-U1198, Université Montpellier, Montpellier 34095, France; Ecole Pratique des Hautes Etudes-Sorbonne, Les Patios Saint-Jacques, 4-14 rue Ferrus, 75014 Paris, France.
| |
Collapse
|
6
|
Gartz Hanson M, Niswander LA. Rectification of muscle and nerve deficits in paralyzed ryanodine receptor type 1 mutant embryos. Dev Biol 2015; 404:76-87. [PMID: 26025922 DOI: 10.1016/j.ydbio.2015.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/21/2015] [Accepted: 05/22/2015] [Indexed: 02/05/2023]
Abstract
Locomotion and respiration require motor axon connectivity and activation of the neuromuscular junction (NMJ). Through a forward genetic screen for muscle weakness, we recently reported an allele of ryanodine receptor type 1 (Ryr1(AG)). Here we reveal a role for functional RyR1 during acetylcholine receptor (AChR) cluster formation and embryonic synaptic transmission. Ryr1(AG) homozygous embryos are non-motile. Motor axons extend past AChR clusters and enlarged AChR clusters are found under fasciculated nerves. Using physiological and pharmacological methods, we show that contractility can be resumed through the masking of a potassium leak, and evoked vesicular release can be resumed via bypassing the defect in RyR1 induced calcium release. Moreover, we show the involvement of ryanodine receptors in presynaptic release at the NMJ. This data provides evidence of a role for RyR1 on both the pre- and postsynaptic sides of the NMJ.
Collapse
Affiliation(s)
- M Gartz Hanson
- Department of Pediatrics University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States.
| | - Lee A Niswander
- Department of Pediatrics University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, United States
| |
Collapse
|
7
|
Niknam Y, Feng W, Cherednichenko G, Dong Y, Joshi SN, Vyas SM, Lehmler HJ, Pessah IN. Structure-activity relationship of selected meta- and para-hydroxylated non-dioxin like polychlorinated biphenyls: from single RyR1 channels to muscle dysfunction. Toxicol Sci 2013; 136:500-13. [PMID: 24014653 DOI: 10.1093/toxsci/kft202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Non-dioxin like polychlorinated biphenyls (NDL-PCBs) are legacy environmental contaminants with contemporary unintentional sources. NDL-PCBs interact with ryanodine receptors (RyRs), Ca(2+) channels of sarcoplasmic/endoplasmic reticulum (SR/ER) that regulate excitation-contraction coupling (ECC) and Ca(2+)-dependent cell signaling in muscle. Activities of 4 chiral congeners PCB91, 95, 132, and 149 and their respective 4- and 5-hydroxy (-OH) derivatives toward rabbit skeletal muscle ryanodine receptor (RyR1) are investigated using [(3)H]ryanodine binding and SR Ca(2+) flux analyses. Although 5-OH metabolites have comparable activity to their respective parent in both assays, 4-OH derivatives are unable to trigger Ca(2+) release from SR microsomes in the presence of Ca(2+)-ATPase activity. PCB95 and derivatives are investigated using single channel voltage-clamp and primary murine embryonic muscle cells (myotubes). Like PCB95, 5-OH-PCB95 quickly and persistently increases channel open probability (p o > .9) by stabilizing the full-open channel state, whereas 4-OH-PCB95 transiently enhances p o. Ca(2+) imaging of myotubes loaded with Fluo-4 show that acute exposure to PCB95 (5 µM) potentiates ECC and caffeine responses and partially depletes SR Ca(2+) stores. Exposure to 5-OH-PCB95 (5 µM) increases cytoplasmic Ca(2+), leading to rapid ECC failure in 50% of myotubes with the remainder retaining negligible responses. 4-OH-PCB95 neither increases baseline Ca(2+) nor causes ECC failure but depresses ECC and caffeine responses by 50%. With longer (3h) exposure to 300 nM PCB95, 5-OH-PCB95, or 4-OH-PCB95 decreases the number of ECC responsive myotubes by 22%, 81%, and 51% compared with control by depleting SR Ca(2+) and/or uncoupling ECC. NDL-PCBs and their 5-OH and 4-OH metabolites differentially influence RyR1 channel activity and ECC in embryonic skeletal muscle.
Collapse
Affiliation(s)
- Yassaman Niknam
- * Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Cocks G, Romanyuk N, Amemori T, Jendelova P, Forostyak O, Jeffries AR, Perfect L, Thuret S, Dayanithi G, Sykova E, Price J. Conditionally immortalized stem cell lines from human spinal cord retain regional identity and generate functional V2a interneurons and motorneurons. Stem Cell Res Ther 2013; 4:69. [PMID: 23759128 PMCID: PMC3706922 DOI: 10.1186/scrt220] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 06/03/2013] [Indexed: 01/24/2023] Open
Abstract
Introduction The use of immortalized neural stem cells either as models of neural development in vitro or as cellular therapies in central nervous system (CNS) disorders has been controversial. This controversy has centered on the capacity of immortalized cells to retain characteristic features of the progenitor cells resident in the tissue of origin from which they were derived, and the potential for tumorogenicity as a result of immortalization. Here, we report the generation of conditionally immortalized neural stem cell lines from human fetal spinal cord tissue, which addresses these issues. Methods Clonal neural stem cell lines were derived from 10-week-old human fetal spinal cord and conditionally immortalized with an inducible form of cMyc. The derived lines were karyotyped, transcriptionally profiled by microarray, and assessed against a panel of spinal cord progenitor markers with immunocytochemistry. In addition, the lines were differentiated and assessed for the presence of neuronal fate markers and functional calcium channels. Finally, a clonal line expressing eGFP was grafted into lesioned rat spinal cord and assessed for survival, differentiation characteristics, and tumorogenicity. Results We demonstrate that these clonal lines (a) retain a clear transcriptional signature of ventral spinal cord progenitors and a normal karyotype after extensive propagation in vitro, (b) differentiate into relevant ventral neuronal subtypes with functional T-, L-, N-, and P/Q-type Ca2+ channels and spontaneous calcium oscillations, and (c) stably engraft into lesioned rat spinal cord without tumorogenicity. Conclusions We propose that these cells represent a useful tool both for the in vitro study of differentiation into ventral spinal cord neuronal subtypes, and for examining the potential of conditionally immortalized neural stem cells to facilitate functional recovery after spinal cord injury or disease.
Collapse
|
9
|
Forostyak O, Romanyuk N, Verkhratsky A, Sykova E, Dayanithi G. Plasticity of calcium signaling cascades in human embryonic stem cell-derived neural precursors. Stem Cells Dev 2013; 22:1506-21. [PMID: 23294113 PMCID: PMC3653370 DOI: 10.1089/scd.2012.0624] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/07/2013] [Indexed: 01/15/2023] Open
Abstract
Human embryonic stem cell-derived neural precursors (hESC NPs) are considered to be a promising tool for cell-based therapy in central nervous system injuries and neurodegenerative diseases. The Ca(2+) ion is an important intracellular messenger essential for the regulation of various cellular functions. We investigated the role and physiology of Ca(2+) signaling to characterize the functional properties of CCTL14 hESC NPs during long-term maintenance in culture (in vitro). We analyzed changes in cytoplasmic Ca(2+) concentration ([Ca(2+)]i) evoked by high K(+), adenosine-5'-triphosphate (ATP), glutamate, γ-aminobutyric acid (GABA), and caffeine in correlation with the expression of various neuronal markers in different passages (P6 through P10) during the course of hESC differentiation. We found that only differentiated NPs from P7 exhibited significant and specific [Ca(2+)]i responses to various stimuli. About 31% of neuronal-like P7 NPs exhibited spontaneous [Ca(2+)]i oscillations. Pharmacological and immunocytochemical assays revealed that P7 NPs express L- and P/Q-type Ca(2+) channels, P2X2, P2X3, P2X7, and P2Y purinoreceptors, glutamate receptors, and ryanodine (RyR1 and RyR3) receptors. The ATP- and glutamate-induced [Ca(2+)]i responses were concentration-dependent. Higher glutamate concentrations (over 100 μM) caused cell death. Responses to ATP were observed in the presence or in the absence of extracellular Ca(2+). These results emphasize the notion that with time in culture, these cells attain a transient period of operative Ca(2+) signaling that is predictive of their ability to act as stem elements.
Collapse
Affiliation(s)
- Oksana Forostyak
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Nataliya Romanyuk
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Alexei Verkhratsky
- School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Eva Sykova
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Neuroscience, Second Medical Faculty, Charles University, Prague, Czech Republic
| | - Govindan Dayanithi
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Institut National de la Santé et de la Recherche Médicale, Unité de recherche U710, Université Montpellier 2, Montpellier; and Ecole Pratique des Hautes Etudes, Paris, France
| |
Collapse
|
10
|
Potenza RL, Armida M, Ferrante A, Pèzzola A, Matteucci A, Puopolo M, Popoli P. Effects of chronic caffeine intake in a mouse model of amyotrophic lateral sclerosis. J Neurosci Res 2013; 91:585-92. [PMID: 23361938 DOI: 10.1002/jnr.23185] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 01/26/2023]
Abstract
Caffeine is a nonselective adenosine receptor antagonist; chronic consumption has proved protective toward neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. The present study was designed to determine whether caffeine intake affected survival and/or motor performance in a transgenic model of amyotrophic lateral sclerosis (ALS). SOD1(G93A) mice received caffeine through drinking water from 70 days of age until death. Body weight, motor performance and survival were evaluated. Furthermore, the expression of adenosine A(2A) receptors (A(2A) Rs), glial glutamate transporter (GLT1), and glial fibrillar acidic protein (GFAP) were evaluated by Western blotting. The results showed that caffeine intake significantly shortened the survival of SOD1(G93A) mice (log rank test, P = 0.01) and induced a nonsignificant advancing of disease onset. The expression of A(2A) R, GLT1, and GFAP was altered in the spinal cords of ALS mice, but caffeine did not influence their expression in either wild-type or SOD1(G93) mice. These data indicate that adenosine receptors may play an important role in ALS.
Collapse
Affiliation(s)
- Rosa Luisa Potenza
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Rome, Italy.
| | | | | | | | | | | | | |
Collapse
|
11
|
Watmuff B, Pouton CW, Haynes JM. In vitro maturation of dopaminergic neurons derived from mouse embryonic stem cells: implications for transplantation. PLoS One 2012; 7:e31999. [PMID: 22384125 PMCID: PMC3285205 DOI: 10.1371/journal.pone.0031999] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/17/2012] [Indexed: 11/18/2022] Open
Abstract
The obvious motor symptoms of Parkinson's disease result from a loss of dopaminergic neurons from the substantia nigra. Embryonic stem cell-derived neural progenitor or precursor cells, adult neurons and fetal midbrain tissue have all been used to replace dying dopaminergic neurons. Transplanted cell survival is compromised by factors relating to the new environment, for example; hypoxia, mechanical trauma and excitatory amino acid toxicity. In this study we investigate, using live-cell fluorescence Ca2+ and Cl− imaging, the functional properties of catecholaminergic neurons as they mature. We also investigate whether GABA has the capacity to act as a neurotoxin early in the development of these neurons. From day 13 to day 21 of differentiation [Cl−]i progressively dropped in tyrosine hydroxylase positive (TH+) neurons from 56.0 (95% confidence interval, 55.1, 56.9) mM to 6.9 (6.8, 7.1) mM. At days 13 and 15 TH+ neurons responded to GABA (30 µM) with reductions in intracellular Cl− ([Cl−]i); from day 21 the majority of neurons responded to GABA (30 µM) with elevations of [Cl−]i. As [Cl−]i reduced, the ability of GABA (30 µM) to elevate intracellular Ca2+ ([Ca2+]i) did also. At day 13 of differentiation a three hour exposure to GABA (30 µM) or L-glutamate (30 µM) increased the number of midbrain dopaminergic (TH+ and Pitx3+) neurons labeled with the membrane-impermeable nuclear dye TOPRO-3. By day 23 cultures were resistant to the effects of both GABA and L-glutamate. We believe that neuronal susceptibility to amino acid excitotoxicity is dependent upon neuronal maturity, and this should be considered when isolating cells for transplantation studies.
Collapse
Affiliation(s)
| | - Colin W. Pouton
- Stem Cell Biology Group, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- * E-mail: (CWP); (JMH)
| | - John M. Haynes
- Stem Cell Biology Group, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- * E-mail: (CWP); (JMH)
| |
Collapse
|
12
|
Komori Y, Tanaka M, Kuba M, Ishii M, Abe M, Kitamura N, Verkhratsky A, Shibuya I, Dayanithi G. Ca(2+) homeostasis, Ca(2+) signalling and somatodendritic vasopressin release in adult rat supraoptic nucleus neurones. Cell Calcium 2010; 48:324-32. [PMID: 21047683 DOI: 10.1016/j.ceca.2010.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 09/29/2010] [Accepted: 10/01/2010] [Indexed: 10/18/2022]
Abstract
Multiple mechanisms that maintain Ca(2+) homeostasis and provide for Ca(2+) signalling operate in the somatas and neurohypophysial nerve terminals of supraoptic nucleus (SON) neurones. Here, we examined the Ca(2+) clearance mechanisms of SON neurones from adult rats by monitoring the effects of the selective inhibition of different Ca(2+) homeostatic molecules on cytosolic Ca(2+) ([Ca(2+)](i)) transients in isolated SON neurones. In addition, we measured somatodendritic vasopressin (AVP) release from intact SON tissue in an attempt to correlate it with [Ca(2+)](i) dynamics. When bathing the cells in a Na(+)-free extracellular solution, thapsigargin, cyclopiazonic acid (CPA), carbonyl cyanide 3-chlorophenylhydrazone (CCCP), and the inhibitor of plasma membrane Ca(2+)-ATPase (PMCA), La(3+), all significantly slowed down the recovery of depolarisation (50 mM KCl)-induced [Ca(2+)](i) transients. The release of AVP was stimulated by 50 mM KCl, and the decline in the peptide release was slowed by Ca(2+) transport inhibitors. In contrast to previous reports, our results show that in the fully mature adult rats: (i) all four Ca(2+) homeostatic pathways, the Na(+)/Ca(2+) exchanger, the endoplasmic reticulum Ca(2+) pump, the plasmalemmal Ca(2+) pump and mitochondria, are complementary in actively clearing Ca(2+) from SON neurones; (ii) somatodendritic AVP release closely correlates with intracellular [Ca(2+)](i) dynamics; (iii) there is (are) Ca(2+) clearance mechanism(s) distinct from the four outlined above; and (iv) Ca(2+) homeostatic systems in the somatas of SON neurones differ from those expressed in their terminals.
Collapse
Affiliation(s)
- Yoko Komori
- University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Dayanithi G, Chen-Kuo-Chang M, Viero C, Hamel C, Muller A, Lenaers G. Characterization of Ca2+ signalling in postnatal mouse retinal ganglion cells: involvement of OPA1 in Ca2+ clearance. Ophthalmic Genet 2010; 31:53-65. [PMID: 20450306 DOI: 10.3109/13816811003698117] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The regulation of Ca(2+) entry and removal is a fine-tuned process which remains not well understood in mouse retinal ganglion cells (RGCs). The latter are known to be sensitive to dysfunctions of mitochondria, organelles playing a pivotal role in Ca(2+) reuptake. METHODS We first described the Ca(2+) signals of RGCs in response to varied drugs with Fura-2 imaging, and secondly tested the role of optic atrophy 1 or OPA1, the gene responsible for Autosomal Dominant Optic Atrophy, on mitochondrial ability to capture intracellular Ca(2+) in cells transfected with the OPA1 small interfering ribonucleic acids (siRNAs). RESULTS In control RGCs, K(+)-evoked [Ca(2+)](i) increase was blocked by the Ca(2+) channel antagonists (Ni(2+)+ Cd(2+)) and GABA(A) receptor agonist muscimol-induced [Ca(2+)](i) responses were attenuated by the GABA(A) receptor antagonists, picrotoxin and gabazine. We also prove the presence of NMDA and AMPA/Kainate (glutamate receptor agonists) responsive receptors in this model. Application of cyclopiazonic acid, an inhibitor of Ca(2+)-ATPase pumps of the intracellular Ca(2+) stores, induced an increase in [Ca(2+)](i) while ryanodine or caffeine had no effect on resting [Ca(2+)](i). Spontaneous Ca(2+) oscillations in contacting neurons highlighted the importance of cross-talks between RGCs during maturation. The mitochondrial respiration uncoupler, carbonyl cyanide 3-chlorophenylhydrazone (CCCP), induced robust raises of intracellular Ca(2+) after K(+) application, with a more pronounced effect in cells silenced for OPA1, which could lead to cell death. CONCLUSIONS Our results indicate an important role of OPA1 in mitochondrial dependent Ca(2+) homeostasis and cell survival in RGCs, suggesting a possible patho-physiological mechanism involved in inherited optic neuropathies.
Collapse
Affiliation(s)
- Govindan Dayanithi
- Institut des Neurosciences de Montpellier, INSERM U583, Montpellier, France
| | | | | | | | | | | |
Collapse
|
14
|
Alteration of sarcoplasmic reticulum ca release in skeletal muscle from calpain 3-deficient mice. Int J Cell Biol 2010; 2009:340346. [PMID: 20300593 PMCID: PMC2838219 DOI: 10.1155/2009/340346] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 12/02/2009] [Indexed: 12/02/2022] Open
Abstract
Mutations of Ca2+-activated proteases (calpains) cause muscular dystrophies. Nevertheless, the specific role of calpains in Ca2+ signalling during the onset of dystrophies remains unclear. We investigated Ca2+ handling in skeletal cells from calpain 3-deficient mice. [Ca2+]i responses to caffeine, a ryanodine receptor (RyR) agonist, were decreased in −/− myotubes and absent in −/− myoblasts. The −/− myotubes displayed smaller amplitudes of the Ca2+ transients induced by cyclopiazonic acid in comparison to wild type cells. Inhibition of L-type Ca2+ channels (LCC) suppressed the caffeine-induced [Ca2+]i responses in −/− myotubes. Hence, the absence of calpain 3 modifies the sarcoplasmic reticulum (SR) Ca2+ release, by a decrease of the SR content, an impairment of RyR signalling, and an increase of LCC activity. We propose that calpain 3-dependent proteolysis plays a role in activating support proteins of intracellular Ca2+ signalling at a stage of cellular differentiation which is crucial for skeletal muscle regeneration.
Collapse
|
15
|
Resende RR, da Costa JL, Kihara AH, Adhikari A, Lorençon E. Intracellular Ca2+ Regulation During Neuronal Differentiation of Murine Embryonal Carcinoma and Mesenchymal Stem Cells. Stem Cells Dev 2010; 19:379-94. [DOI: 10.1089/scd.2008.0289] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Rodrigo R. Resende
- Department of Physics, Institute of Exacts Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Instituto de Ensino e Pesquisa Santa Casa de BH (ISCM-BH), Belo Horizante, Brazil
| | - José L. da Costa
- Instrumental Analysis Laboratory, Criminalistic Institute of São Paulo, São Paulo, Brazil; Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Alexandre H. Kihara
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Santo André, Brasil
| | - Avishek Adhikari
- Department of Biological Sciences, Columbia University, New York
| | - Eudes Lorençon
- Department of Physics, Institute of Exacts Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
16
|
Characterization of rhythmic Ca2+ transients in early embryonic chick motoneurons: Ca2+ sources and effects of altered activation of transmitter receptors. J Neurosci 2009; 29:15232-44. [PMID: 19955376 DOI: 10.1523/jneurosci.3809-09.2009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In the nervous system, spontaneous Ca(2+) transients play important roles in many developmental processes. We previously found that altering the frequency of electrically recorded rhythmic spontaneous bursting episodes in embryonic chick spinal cords differentially perturbed the two main pathfinding decisions made by motoneurons, dorsal-ventral and pool-specific, depending on the sign of the frequency alteration. Here, we characterized the Ca(2+) transients associated with these bursts and showed that at early stages while motoneurons are still migrating and extending axons to the base of the limb bud, they display spontaneous, highly rhythmic, and synchronized Ca(2+) transients. Some precursor cells in the ependymal layer displayed similar transients. T-type Ca(2+) channels and a persistent Na(+) current were essential to initiate spontaneous bursts and associated transients. However, subsequent propagation of activity throughout the cord resulted from network-driven chemical transmission mediated presynaptically by Ca(2+) entry through N-type Ca(2+) channels and postsynaptically by acetylcholine acting on nicotinic receptors. The increased [Ca(2+)](i) during transients depended primarily on L-type and T-type channels with a modest contribution from TRP (transient receptor potential) channels and ryanodine-sensitive internal stores. Significantly, the drugs used previously to produce pathfinding errors altered transient frequency but not duration or amplitude. These observations imply that different transient frequencies may differentially modulate motoneuron pathfinding. However, the duration of the Ca(2+) transients differed significantly between pools, potentially enabling additional distinct pool-specific downstream signaling. Many early events in spinal motor circuit formation are thus potentially sensitive to the rhythmic Ca(2+) transients we have characterized and to any drugs that perturb them.
Collapse
|
17
|
Brunet N, Tarabal O, Esquerda JE, Calderó J. Excitotoxic motoneuron degeneration induced by glutamate receptor agonists and mitochondrial toxins in organotypic cultures of chick embryo spinal cord. J Comp Neurol 2009; 516:277-90. [PMID: 19634179 DOI: 10.1002/cne.22118] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Glutamate receptor-mediated excitotoxicity and mitochondrial dysfunction appear to play an important role in motoneuron (MN) degeneration in amyotrophic lateral sclerosis (ALS). In the present study we used an organotypic slice culture of chick embryo spinal cord to explore the responsiveness of mature MNs to different excitotoxic stimuli and mitrochondrial inhibition. We found that, in this system, MNs are highly vulnerable to excitotoxins such as glutamate, N-methyl-D-aspartate (NMDA), and kainate (KA), and that the neuroprotective drug riluzole rescues MNs from KA-mediated excitotoxic death. MNs are also sensitive to chronic mitochondrial inhibition induced by malonate and 3-nitropropionic acid (3-NP) in a dose-dependent manner. MN degeneration induced by treatment with mitochondrial toxins displays structural changes similar to those seen following excitotoxicity and can be prevented by applying either the antiexcitotoxic drug 6-cyano-7-nitroquinoxaline-2,3-dione disodium (CNQX) or riluzole. Excitotoxicity results in an increased frequency of normal spontaneous Ca2+ oscillations in MNs, which is followed by a sustained deregulation of intracellular Ca2+. Tolerance to excitotoxic MN death resulting from chronic exposure to excitotoxins correlates with a reduced excitotoxin-induced increase in intracellular Ca2+ and increased thapsigargin-sensitive Ca2+ stores.
Collapse
Affiliation(s)
- Núria Brunet
- Unitat de Neurobiologia Cel.lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), 25008 Lleida, Catalonia, Spain
| | | | | | | |
Collapse
|
18
|
Nuñez JL, McCarthy MM. Resting intracellular calcium concentration, depolarizing Gamma-Aminobutyric Acid and possible role of local estradiol synthesis in the developing male and female hippocampus. Neuroscience 2009; 158:623-34. [PMID: 19007865 PMCID: PMC2660432 DOI: 10.1016/j.neuroscience.2008.09.061] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/25/2008] [Accepted: 10/02/2008] [Indexed: 01/31/2023]
Abstract
The maturation of the hippocampus is impacted by a multitude of factors, including the regulation of intracellular calcium levels. Depolarizing actions of Gamma-Aminobutyric Acid (GABA) can profoundly alter intracellular calcium in immature hippocampal neurons via influx through voltage-gated calcium channels. We here report fundamental sex differences in properties of depolarizing GABA responses and in resting intracellular calcium in neonatal cultured hippocampal neurons. The effects of the estrogen receptor antagonist, ICI 182,780, and the estradiol-synthesis inhibitor, formestane, indicate the sex differences in depolarizing GABA responses are at least in part due to de novo estradiol synthesis by female neurons, whereas a sex difference in resting calcium is independent of steroids. We postulate that local estradiol synthesis in cultured female hippocampal neurons affects the kinetics of either the GABA(A) receptor or voltage sensitive calcium channels. These data highlight the fact that immature hippocampal neurons exhibit fundamentally different physiological properties in males versus females. Elucidating how and where immature male and female neurons differ is essential for a complete understanding of normal rodent brain development.
Collapse
Affiliation(s)
- J L Nuñez
- Department of Physiology, Program in Neuroscience, University of Maryland, 655 W Baltimore Street, Baltimore, MD 21201, USA.
| | | |
Collapse
|
19
|
Foradori CD, Handa RJ. Living or dying in three quarter time: neonatal orchestration of hippocampal cell death pathways by androgens and excitatory GABA. Exp Neurol 2008; 213:1-6. [PMID: 18617165 DOI: 10.1016/j.expneurol.2008.04.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 04/25/2008] [Accepted: 04/30/2008] [Indexed: 11/18/2022]
Affiliation(s)
- C D Foradori
- Department of Biomedical Sciences, Neurobiology Section, Colorado State University, Fort Collins, CO 80523, USA
| | | |
Collapse
|
20
|
Resende RR, Gomes KN, Adhikari A, Britto LRG, Ulrich H. Mechanism of acetylcholine-induced calcium signaling during neuronal differentiation of P19 embryonal carcinoma cells in vitro. Cell Calcium 2008; 43:107-21. [PMID: 17662384 DOI: 10.1016/j.ceca.2007.04.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 04/12/2007] [Accepted: 04/13/2007] [Indexed: 12/20/2022]
Abstract
Muscarinic (mAChRs) and nicotinic acetylcholine receptors (nAChRs) are involved in various physiological processes, including neuronal development. We provide evidence for expression of functional nicotinic and muscarinic receptors during differentiation of P19 carcinoma embryonic cells, as an in vitro model of early neurogenesis. We have detected expression and activity of alpha(2)-alpha(7), beta(2), beta(4) nAChR and M1-M5 mAChR subtypes during neuronal differentiation. Nicotinic alpha(3) and beta(2) mRNA transcription was induced by addition of retinoic acid to P19 cells. Gene expression of alpha(2), alpha(4)-alpha(7), beta(4) nAChR subunits decreased during initial differentiation and increased again when P19 cells underwent final maturation. Receptor response in terms of nicotinic agonist-evoked Ca(2+) flux was observed in embryonic and neuronal-differentiated cells. Muscarinic receptor response, merely present in undifferentiated P19 cells, increased during neuronal differentiation. The nAChR-induced elevation of intracellular calcium ([Ca(2+)](i)) response in undifferentiated cells was due to Ca(2+) influx. In differentiated P19 neurons the nAChR-induced [Ca(2+)](i) response was reduced following pretreatment with ryanodine, while the mAChR-induced response was unaffected indicating the contribution of Ca(2+) release from ryanodine-sensitive stores to nAChR- but not mAChR-mediated Ca(2+) responses. The presence of functional nAChRs in embryonic cells suggests that these receptors are involved in triggering Ca(2+) waves during initial neuronal differentiation.
Collapse
Affiliation(s)
- Rodrigo R Resende
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | | | | | | |
Collapse
|
21
|
Nuñez JL, McCarthy MM. Androgens predispose males to GABAA-mediated excitotoxicity in the developing hippocampus. Exp Neurol 2008; 210:699-708. [PMID: 18289534 DOI: 10.1016/j.expneurol.2008.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 12/20/2007] [Accepted: 01/04/2008] [Indexed: 01/07/2023]
Abstract
Clinical evidence and animal models indicate greater brain damage in newborn males following injury. In adults, glutamate is the primary source of excitotoxic cell death and the steroid, estradiol, is neuroprotective. In neonatal brain, membrane depolarization following activation of GABAA receptors is the major source of excitation. Consequent influx of calcium via L-type channels is normally trophic, but becomes excitotoxic during periods of excessive activation of GABAA receptors, such as hypoxia-ischemia, alcohol exposure and seizures. The use of sex-specific hippocampal cultures revealed greater cell death induced by the GABAA agonist, muscimol, in male- versus female-derived cultures. Pretreatment with the androgen, dihydrotestosterone (DHT) increased muscimol-induced death in both sexes. Exploration of calcium dynamics indicated that, counter to expectation, female neurons achieved higher [Ca2+]i than male, but the calcium transient duration was shorter due to faster rise and decay. However, a second exposure to muscimol within minutes of the first, caused significant attenuation of [Ca2+]i in female neurons. In contrast, while male neurons exposed to muscimol for the first time exhibited lower maximal [Ca2+]i, when exposed to muscimol again there was no attenuation in [Ca2+]i. The latter effect was induced in females by DHT, and inversely correlated with the amount of gamma2 subunit of the GABAA receptor. This novel effect of androgen on GABA-mediated excitotoxicty suggests a unique opportunity for a sex-specific therapeutic approach involving antagonism of the androgen receptor in neonatal males at risk for brain injury.
Collapse
Affiliation(s)
- Joseph L Nuñez
- Department of Physiology, University of Maryland, Baltimore, Baltimore, MD 21201, USA.
| | | |
Collapse
|
22
|
Bui TV, Grande G, Rose PK. Multiple modes of amplification of synaptic inhibition to motoneurons by persistent inward currents. J Neurophysiol 2007; 99:571-82. [PMID: 18046007 DOI: 10.1152/jn.00717.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability of inhibitory synaptic inputs to dampen the excitability of motoneurons is augmented when persistent inward currents (PICs) are activated. This amplification could be due to an increase in the driving potential of inhibitory synapses or the deactivation of the channels underlying PICs. Our goal was to determine which mechanism leads to the amplification of inhibitory inputs by PICs. To reach this goal, we measured inhibitory postsynaptic currents (IPSCs) in decerebrate cats during somatic voltage-clamp steps. These IPSCs were generated by tonic activation of Renshaw cells. The IPSCs exhibited a rapid rise and a slower decay to a plateau level. Activation of PICs always led to an increase in the peak of the IPSC, but the amount of decay after the peak of the IPSC was inversely related to the size of the IPSC. These results were replicated in simulations based on compartmental models of motoneurons incorporating distributions of Renshaw cell synapses based on anatomical observations, and L-type calcium channels distributed as 100-microm-long hot spots centered 100 to 400 microm away from the soma. For smaller IPSCs, amplification by PICs was due to an increase in the driving force of the inhibitory synaptic current. For larger IPSCs, amplification was caused by deactivation of the channels underlying PICs leading to a lesser decay of the IPSCs. As a result of this change in the time course of the IPSC, deactivation of the channels underlying PICs leads to a greater amplification of the total inhibitory synaptic current.
Collapse
Affiliation(s)
- Tuan V Bui
- Canadian Institutes of Health Research Group in Sensory-Motor Systems, Department of Physiology, Centre for Neuroscience Studies, Queen's University, Kingston, Canada
| | | | | |
Collapse
|
23
|
Dayanithi G, Desmadryl G, Travo C, Chabbert C, Sans A. Trimetazidine modulates AMPA/kainate receptors in rat vestibular ganglion neurons. Eur J Pharmacol 2007; 574:8-14. [PMID: 17658512 DOI: 10.1016/j.ejphar.2007.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 06/26/2007] [Accepted: 07/04/2007] [Indexed: 11/24/2022]
Abstract
Trimetazidine (1[2,3,4-trimethoxy-benzyl] piperazine, 2 HCl) is an anti-ischemic agent frequently administered as a prophylactic treatment for episodes of angina pectoris and chorioretinal disturbances. It is also employed as a symptomatic treatment of vertigo but its mechanism of action is yet to be defined. Using Fura-2 fluorescence photometry and whole-cell patch-clamp recordings we investigated the effect of trimetazidine on the [Ca(2+)](i) and current responses induced by the application of non-N-methyl-D-aspartate (NMDA) receptor agonists on low density vestibular ganglion neuronal cultures explanted from 3 day s postnatal rats. Trimetazidine blocked the [Ca(2+)](i) and current responses induced by 100 microM applications of both kainate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA). These responses were dependent on external Ca(2+) and were blocked by the voltage-dependent Ca(2+) channel blockers Ni(2+) and Cd(2+) . Trimetazidine only acts on the AMPA/kainate receptors and had no effect on K(+)-induced depolarizations. Dose-dependent curves were obtained for the inhibition by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and trimetazidine (IC(50) 7 microM and 0.7 microM) of kainate stimulations. After AMPA stimulation, dose-response inhibition curves showed an IC(50) of 3 microM for CNQX and 25 microM for trimetazidine. These results indicate that trimetazidine could be a potent antagonist of AMPA/kainate receptors in vestibular ganglion neurons. This may explain the protective role of trimetazidine in the inner ear suggesting an anti-excitotoxic activity.
Collapse
MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Analysis of Variance
- Animals
- Calcium/physiology
- Calcium Channel Blockers/pharmacology
- Cations, Divalent
- Cells, Cultured
- Dose-Response Relationship, Drug
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- Fluorescent Dyes
- Fura-2
- Ganglia, Sensory/drug effects
- Neurons/drug effects
- Neurons/physiology
- Patch-Clamp Techniques
- Rats
- Rats, Wistar
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Receptors, Kainic Acid/antagonists & inhibitors
- Receptors, Kainic Acid/metabolism
- Trimetazidine/pharmacology
- Vasodilator Agents/pharmacology
- Vestibule, Labyrinth/innervation
Collapse
Affiliation(s)
- Govindan Dayanithi
- INSERM, U 583, Institut des Neurosciences de Montpellier, Hôpital St Eloi, 80 rue Augustin Fliche, F-34091, Montpellier cedex 5, France
| | | | | | | | | |
Collapse
|
24
|
Lee SH, Park KH, Ho WK, Lee SH. Postnatal developmental changes in Ca2+ homeostasis in supraoptic magnocellular neurons. Cell Calcium 2007; 41:441-50. [PMID: 17010427 DOI: 10.1016/j.ceca.2006.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 08/10/2006] [Accepted: 08/24/2006] [Indexed: 11/16/2022]
Abstract
Supraoptic magnocellular neurons (SMNs) undergo dramatic changes in morphological and electrical properties during postnatal development. We investigated the developmental change in Ca2+ homeostasis in SMNs. The decay rate of Ca2+ transients markedly increased during the third postnatal week (PW3) to an adult level. This increase in the Ca2+ decay rate was paralleled by hypertrophy of the SMN somata. Activity of Na+/Ca2+ exchanger (Na/CaX) and sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) was quantified as a decrement in the Ca2+ decay rate caused by extracellular [Na+] reduction and that by thapsigargin, respectively. SERCA activity was negligible during PW2, and markedly increased during PW3. SERCA activity and soma size remained stable thereafter. Na/CaX activity was a major Ca2+-clearance mechanism (CCM) during PW2, increased further during PW3, but was negligible in mature SMNs (PW10). In parallel with the decrease in Na/CaX activity, endogenous Ca2+ buffering capacity declined, resulting that the apparent Ca2+ decay rate remained relatively constant between PW4 and PW10. Replacement of intracellular K+ with Li+ had no effect on Na/CaX activity, suggesting that NCX rather than NCKX comprises Na/CaX. These findings indicate a developmental shift in the balance of CCMs from Ca2+ extrusion via NCX toward Ca2+ sequestration into endoplasmic reticulum via SERCA.
Collapse
Affiliation(s)
- Sang Hun Lee
- National Research Laboratory for Cell Physiology, Department of Physiology, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Ku, Seoul 110-799, South Korea
| | | | | | | |
Collapse
|
25
|
Viéro C, Méchaly I, Aptel H, Puech S, Valmier J, Bancel F, Dayanithi G. Rapid inhibition of Ca2+ influx by neurosteroids in murine embryonic sensory neurones. Cell Calcium 2006; 40:383-91. [PMID: 16769113 DOI: 10.1016/j.ceca.2006.04.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 04/09/2006] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
The non-genomic role of neuroactive steroids on [Ca2+]i transients induced by GABA receptor activation was investigated in cultured dorsal root ganglia (DRG) neurones at embryonic stage E13. [Ca2+]i measurements were performed with Fura-2 fast fluorescence microfluorimetry. Application of the GABAA receptor agonist muscimol (Musci) evoked an increase in [Ca2+]i, confirming the excitatory effect of GABA at this embryonic stage. The muscimol-induced [Ca2+]i response was inhibited by progesterone (Proges) and its primary metabolite allopregnanolone (Allo) in a rapid, reversible and dose-dependent manner. These calcium transients were suppressed in the absence of external Ca2+ or in the presence of Ni2+ + Cd2+ suggesting an involvement of voltage-activated Ca2+ channels. In contrast, none of these steroids affected the resting [Ca2+]i nor exhibited any inhibitory effect on 50 mM KCl-induced [Ca2+]i increases. In view of the well-established potentiation of GABAA receptor by direct binding of neurosteroids, the inhibitory effects described in this study seem to involve distinct mechanisms. This new inhibitory effect of progesterone is observed at low and physiological concentrations, is rapid and independent of RU38486, an antagonist of the classic progesterone receptor, probably involving a membrane receptor. Using RT-PCR, we demonstrated the expression of progesterone receptor membrane component 1 (Pgrmc1), encoding 25-Dx, a membrane-associated progesterone binding protein in DRG neurones at different stages of development. In conclusion, we describe for the first time a rapid effect of progestins on embryonic DRG neurones involving an antagonistic effect of progesterone and allopregnanolone on GABAA receptors.
Collapse
Affiliation(s)
- Cédric Viéro
- INSERM U 583, Institut des Neurosciences de Montpellier, Hôpital St Eloi, BP 74103, 80 rue Augustin Fliche, F-34091 Montpellier, Cedex 5, France
| | | | | | | | | | | | | |
Collapse
|