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Taha M, Cartereau A, Taillebois E, Thany SH. Flupyradifurone activates DUM neuron nicotinic acetylcholine receptors and stimulates an increase in intracellular calcium through the ryanodine receptors. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 205:106147. [PMID: 39477600 DOI: 10.1016/j.pestbp.2024.106147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 09/16/2024] [Accepted: 09/22/2024] [Indexed: 11/07/2024]
Abstract
Insect neuronal nicotinic acetylcholine receptors (nAChRs) are transmembrane receptors that play a key role in the development and synaptic plasticity of both vertebrates and invertebrates, and are considered to be major targets of several insecticides. We used dorsal unpaired median (DUM) neurons, which are insect neurosecretory cells, to explore what type of nAChRs are involved in flupyradifurone's (FLU) mode of action, and to study the role of calcium release from intracellular stores in this process. Using whole-cell patch-clamp and fura-2-AM calcium imaging techniques, we found that inhibition of IP3Rs through application of 2-APB reduced FLU inward currents, but did not affect the intracellular calcium release induced by FLU. In contrast, inhibition of RyRs using ryanodine, led to reduction of intracellular calcium increase following FLU pulse application. These results suggested that FLU inward currents are likely due to a combination of the direct effects of FLU on DUM neuron nAChRs and the subsequent calcium release from RyRs.
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Affiliation(s)
- Maria Taha
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067 Orléans, France
| | - Alison Cartereau
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067 Orléans, France
| | - Emiliane Taillebois
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067 Orléans, France
| | - Steeve H Thany
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067 Orléans, France; Institut Universitaire de France, 1 rue Descartes, 75005 Paris, France.
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2
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Geisler SM, Ottaviani MM, Jacobo-Piqueras N, Theiner T, Mastrolia V, Guarina L, Ebner K, Obermair GJ, Carbone E, Tuluc P. Deletion of the α 2δ-1 calcium channel subunit increases excitability of mouse chromaffin cells. J Physiol 2024; 602:3793-3814. [PMID: 39004870 DOI: 10.1113/jp285681] [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: 09/13/2023] [Accepted: 06/26/2024] [Indexed: 07/16/2024] Open
Abstract
High voltage-gated Ca2+ channels (HVCCs) shape the electrical activity and control hormone release in most endocrine cells. HVCCs are multi-subunit protein complexes formed by the pore-forming α1 and the auxiliary β, α2δ and γ subunits. Four genes code for the α2δ isoforms. At the mRNA level, mouse chromaffin cells (MCCs) express predominantly the CACNA2D1 gene coding for the α2δ-1 isoform. Here we show that α2δ-1 deletion led to ∼60% reduced HVCC Ca2+ influx with slower inactivation kinetics. Pharmacological dissection showed that HVCC composition remained similar in α2δ-1-/- MCCs compared to wild-type (WT), demonstrating that α2δ-1 exerts similar functional effects on all HVCC isoforms. Consistent with reduced HVCC Ca2+ influx, α2δ-1-/- MCCs showed reduced spontaneous electrical activity with action potentials (APs) having a shorter half-maximal duration caused by faster rising and decay slopes. However, the induced electrical activity showed opposite effects with α2δ-1-/- MCCs displaying significantly higher AP frequency in the tonic firing mode as well as an increase in the number of cells firing AP bursts compared to WT. This gain-of-function phenotype was caused by reduced functional activation of Ca2+-dependent K+ currents. Additionally, despite the reduced HVCC Ca2+ influx, the intracellular Ca2+ transients and vesicle exocytosis or endocytosis were unaltered in α2δ-1-/- MCCs compared to WT during sustained stimulation. In conclusion, our study shows that α2δ-1 genetic deletion reduces Ca2+ influx in cultured MCCs but leads to a paradoxical increase in catecholamine secretion due to increased excitability. KEY POINTS: Deletion of the α2δ-1 high voltage-gated Ca2+ channel (HVCC) subunit reduces mouse chromaffin cell (MCC) Ca2+ influx by ∼60% but causes a paradoxical increase in induced excitability. MCC intracellular Ca2+ transients are unaffected by the reduced HVCC Ca2+ influx. Deletion of α2δ-1 reduces the immediately releasable pool vesicle exocytosis but has no effect on catecholamine (CA) release in response to sustained stimuli. The increased electrical activity and CA release from MCCs might contribute to the previously reported cardiovascular phenotype of patients carrying α2δ-1 loss-of-function mutations.
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Affiliation(s)
- Stefanie M Geisler
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Matteo M Ottaviani
- Department of Drug Science, NIS Centre, University of Torino, Torino, Italy
| | - Noelia Jacobo-Piqueras
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Tamara Theiner
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Vincenzo Mastrolia
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Laura Guarina
- Department of Drug Science, NIS Centre, University of Torino, Torino, Italy
| | - Karl Ebner
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Gerald J Obermair
- Division of Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Emilio Carbone
- Department of Drug Science, NIS Centre, University of Torino, Torino, Italy
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
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Crapart CC, Scott ZC, Konno T, Sharma A, Parutto P, Bailey DMD, Westrate LM, Avezov E, Koslover EF. Luminal transport through intact endoplasmic reticulum limits the magnitude of localized Ca 2+ signals. Proc Natl Acad Sci U S A 2024; 121:e2312172121. [PMID: 38502705 PMCID: PMC10990089 DOI: 10.1073/pnas.2312172121] [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: 07/17/2023] [Accepted: 02/09/2024] [Indexed: 03/21/2024] Open
Abstract
The endoplasmic reticulum (ER) forms an interconnected network of tubules stretching throughout the cell. Understanding how ER functionality relies on its structural organization is crucial for elucidating cellular vulnerability to ER perturbations, which have been implicated in several neuronal pathologies. One of the key functions of the ER is enabling Ca[Formula: see text] signaling by storing large quantities of this ion and releasing it into the cytoplasm in a spatiotemporally controlled manner. Through a combination of physical modeling and live-cell imaging, we demonstrate that alterations in ER shape significantly impact its ability to support efficient local Ca[Formula: see text] releases, due to hindered transport of luminal content within the ER. Our model reveals that rapid Ca[Formula: see text] release necessitates mobile luminal buffer proteins with moderate binding strength, moving through a well-connected network of ER tubules. These findings provide insight into the functional advantages of normal ER architecture, emphasizing its importance as a kinetically efficient intracellular Ca[Formula: see text] delivery system.
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Affiliation(s)
- Cécile C. Crapart
- UK Dementia Research Institute at the University of Cambridge, CambridgeCB2 0AH, United Kingdom
- Department of Clinical Neurosciences, School of Clinical Medicine, The University of Cambridge, CambridgeCB2 0AH, United Kingdom
| | | | - Tasuku Konno
- UK Dementia Research Institute at the University of Cambridge, CambridgeCB2 0AH, United Kingdom
- Department of Clinical Neurosciences, School of Clinical Medicine, The University of Cambridge, CambridgeCB2 0AH, United Kingdom
| | - Aman Sharma
- Department of Physics, University of California, San Diego, La Jolla, CA92130
| | - Pierre Parutto
- UK Dementia Research Institute at the University of Cambridge, CambridgeCB2 0AH, United Kingdom
- Department of Clinical Neurosciences, School of Clinical Medicine, The University of Cambridge, CambridgeCB2 0AH, United Kingdom
| | - David M. D. Bailey
- UK Dementia Research Institute at the University of Cambridge, CambridgeCB2 0AH, United Kingdom
- Department of Clinical Neurosciences, School of Clinical Medicine, The University of Cambridge, CambridgeCB2 0AH, United Kingdom
| | - Laura M. Westrate
- Department of Chemistry and Biochemistry, Calvin University, Grand Rapids, MI49546
| | - Edward Avezov
- UK Dementia Research Institute at the University of Cambridge, CambridgeCB2 0AH, United Kingdom
- Department of Clinical Neurosciences, School of Clinical Medicine, The University of Cambridge, CambridgeCB2 0AH, United Kingdom
| | - Elena F. Koslover
- Department of Physics, University of California, San Diego, La Jolla, CA92130
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Parada-Parra OJ, Hernández-Cruz A. Effects of reversible SERCA inhibition on catecholamine exocytosis and intracellular [Ca 2+] signaling in chromaffin cells from normotensive Wistar Kyoto rats and spontaneously hypertensive rats. Pflugers Arch 2024; 476:123-144. [PMID: 37775569 PMCID: PMC10758371 DOI: 10.1007/s00424-023-02859-z] [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: 03/17/2023] [Revised: 08/15/2023] [Accepted: 09/11/2023] [Indexed: 10/01/2023]
Abstract
Intracellular Ca2+ ([Ca2+]i) signaling and catecholamine (CA) exocytosis from adrenal chromaffin cells (CCs) differ between mammalian species. These differences partly result from the different contributions of Ca2+-induced Ca2+-release (CICR) from internal stores, which boosts intracellular Ca2+ signals. Transient inhibition of the sarcoendoplasmic reticulum (SERCA) Ca2+ pump with cyclopiazonic acid (CPA) reduces CICR. Recently, Martínez-Ramírez et al. found that CPA had contrasting effects on catecholamine secretion and intracellular Ca2+ signals in mouse and bovine CCs, where it enhanced and inhibited exocytosis, respectively. After CPA withdrawal, exocytosis diminished in mouse CCs and increased in bovine CCs. These differences can be explained if mouse CCs have weak CICR and strong Ca2+ uptake, and the reverse is true for bovine CCs. Surprisingly, CPA slightly reduced the amplitude of Ca2+ signals in both mouse and bovine CCs. Here we examined the effects of CPA on stimulated CA exocytosis and Ca2+ signaling in rat CCs and investigated if it alters differently the responses of CCs from normotensive (WKY) or hypertensive (SHR) rats, which differ in the gain of CICR. Our results demonstrate that CPA application strongly inhibits voltage-gated exocytosis and Ca2+ transients in rat CCs, regardless of strain (SHR or WKY). Thus, despite the greater phylogenetic distance from the most recent common ancestors, suppression of endoplasmic reticulum (ER) Ca2+ uptake through CPA inhibits the CA secretion in rat CCs more similarly to bovine than mouse CCs, unveiling divergent evolutionary relationships in the mechanism of CA exocytosis of CCs between rodents. Agents that inhibit the SERCA pump, such as CPA, suppress catecholamine secretion equally well in WKY and SHR CCs and are not potential therapeutic agents for hypertension. Rat CCs display Ca2+ signals of varying widths. Some even show early and late Ca2+ components. Narrowing the Ca2+ transients by CPA and ryanodine suggests that the late component is mainly due to CICR. Simultaneous recordings of Ca2+ signaling and amperometry in CCs revealed the existence of a robust and predictable correlation between the kinetics of the whole-cell intracellular Ca2+ signal and the rate of exocytosis at the single-cell level.
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Affiliation(s)
- Oscar J Parada-Parra
- Departamento Neurociencia Cognitiva, and Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito de La Investigación Científica S/N, Ciudad Universitaria, Mexico City CDMX, C.P. 04510, México
| | - Arturo Hernández-Cruz
- Departamento Neurociencia Cognitiva, and Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito de La Investigación Científica S/N, Ciudad Universitaria, Mexico City CDMX, C.P. 04510, México.
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Mitronova GY, Quentin C, Belov VN, Wegener JW, Kiszka KA, Lehnart SE. 1,4-Benzothiazepines with Cyclopropanol Groups and Their Structural Analogues Exhibit Both RyR2-Stabilizing and SERCA2a-Stimulating Activities. J Med Chem 2023; 66:15761-15775. [PMID: 37991191 PMCID: PMC10726367 DOI: 10.1021/acs.jmedchem.3c01235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023]
Abstract
To discover new multifunctional agents for the treatment of cardiovascular diseases, we designed and synthesized a series of compounds with a cyclopropyl alcohol moiety and evaluated them in biochemical assays. Biological screening identified derivatives with dual activity: preventing Ca2+ leak through ryanodine receptor 2 (RyR2) and enhancing cardiac sarco-endoplasmic reticulum (SR) Ca2+ load by activation of Ca2+-dependent ATPase 2a (SERCA2a). The compounds that stabilize RyR2 at micro- and nanomolar concentrations are either structurally related to RyR-stabilizing drugs or Rycals or have structures similar to them. The novel compounds also demonstrate a good ability to increase ATP hydrolysis mediated by SERCA2a activity in cardiac microsomes, e.g., the half-maximal effective concentration (EC50) was as low as 383 nM for compound 12a, which is 1,4-benzothiazepine with two cyclopropanol groups. Our findings indicate that these derivatives can be considered as new lead compounds to improve cardiac function in heart failure.
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Affiliation(s)
- Gyuzel Y. Mitronova
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
| | - Christine Quentin
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Vladimir N. Belov
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Jörg W. Wegener
- Department
of Cardiology & Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Strasse 42a, Göttingen 37075, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
| | - Kamila A. Kiszka
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Stephan E. Lehnart
- Department
of Cardiology & Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Strasse 42a, Göttingen 37075, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
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6
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Santo-Domingo J, Álvarez-Illera P, Montenegro P, Fonteriz RI, Montero M, Álvarez J. Measurements of Calcium in Chromaffin Cell Organelles Using Targeted Aequorins. Methods Mol Biol 2023; 2565:153-177. [PMID: 36205893 DOI: 10.1007/978-1-0716-2671-9_11] [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] [Indexed: 06/16/2023]
Abstract
The molecular mechanisms that mediate and regulate calcium (Ca2+) fluxes through the membranes of intracellular organelles play a key role in the generation and shaping of the local and global cytosolic Ca2+ signals triggering the process of regulated exocytosis in chromaffin cells. Beyond that role, intraorganellar Ca2+ homeostasis also regulates organelle-specific processes such as oxidative phosphorylation in mitochondria, maturation of secretory granules, or stress in the endoplasmic reticulum. In this chapter, we describe current methods to study mitochondrial, endoplasmic reticulum, and secretory vesicle calcium homeostasis in living chromaffin cells using engineered targeted aequorins.
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Affiliation(s)
- Jaime Santo-Domingo
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain.
| | - Pilar Álvarez-Illera
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Pablo Montenegro
- Pharmacology Unit, Department of Physical Medicine and Pharmacology, Medical School, Universidad de La Laguna, Tenerife, Spain
| | - Rosalba I Fonteriz
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Mayte Montero
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Javier Álvarez
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
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7
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Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
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de Pascual R, Calzaferri F, Gonzalo PC, Serrano-Nieto R, de los Ríos C, García AG, Gandía L. Novel Purine Derivative ITH15004 Facilitates Exocytosis through a Mitochondrial Calcium-Mediated Mechanism. Int J Mol Sci 2021; 23:440. [PMID: 35008868 PMCID: PMC8745631 DOI: 10.3390/ijms23010440] [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: 12/06/2021] [Revised: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 02/08/2023] Open
Abstract
Upon depolarization of chromaffin cells (CCs), a prompt release of catecholamines occurs. This event is triggered by a subplasmalemmal high-Ca2+ microdomain (HCMD) generated by Ca2+ entry through nearby voltage-activated calcium channels. HCMD is efficiently cleared by local mitochondria that avidly take up Ca2+ through their uniporter (MICU), then released back to the cytosol through mitochondrial Na+/Ca2+ exchanger (MNCX). We found that newly synthesized derivative ITH15004 facilitated the release of catecholamines triggered from high K+-depolarized bovine CCs. Such effect seemed to be due to regulation of mitochondrial Ca2+ circulation because: (i) FCCP-potentiated secretory responses decay was prevented by ITH15004; (ii) combination of FCCP and ITH15004 exerted additive secretion potentiation; (iii) such additive potentiation was dissipated by the MICU blocker ruthenium red (RR) or the MNCX blocker CGP37157 (CGP); (iv) combination of FCCP and ITH15004 produced both additive augmentation of cytosolic Ca2+ concentrations ([Ca2+]c) K+-challenged BCCs, and (v) non-inactivated [Ca2+]c transient when exposed to RR or CGP. On pharmacological grounds, data suggest that ITH15004 facilitates exocytosis by acting on mitochondria-controlled Ca2+ handling during K+ depolarization. These observations clearly show that ITH15004 is a novel pharmacological tool to study the role of mitochondria in the regulation of the bioenergetics and exocytosis in excitable cells.
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Affiliation(s)
- Ricardo de Pascual
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/Diego de León, 62, 28006 Madrid, Spain
| | - Francesco Calzaferri
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
- Institut des Biomolécules Max Mousseron (IBMM—UMR5247, CNRS), 1919 Route de Mende, CEDEX 5, 34293 Montpellier, France
| | - Paula C. Gonzalo
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
| | - Rubén Serrano-Nieto
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
| | - Cristóbal de los Ríos
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/Diego de León, 62, 28006 Madrid, Spain
- Departamento de Ciencias Básicas de la Salud, Campus de Alcorcon, Universidad Rey Juan Carlos, Avda. Atenas s/n, 28922 Alcorcón, Spain
| | - Antonio G. García
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/Diego de León, 62, 28006 Madrid, Spain
- Fundación Teófilo Hernando, Parque Científico de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Luis Gandía
- Instituto Teófilo Hernando and Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029 Madrid, Spain; (R.d.P.); (F.C.); (P.C.G.); (R.S.-N.); (C.d.l.R.); (A.G.G.)
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/Diego de León, 62, 28006 Madrid, Spain
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Verkhratsky A, Parpura V, Li B, Scuderi C. Astrocytes: The Housekeepers and Guardians of the CNS. ADVANCES IN NEUROBIOLOGY 2021; 26:21-53. [PMID: 34888829 DOI: 10.1007/978-3-030-77375-5_2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Astroglia are a diverse group of cells in the central nervous system. They are of the ectodermal, neuroepithelial origin and vary in morphology and function, yet, they can be collectively defined as cells having principle function to maintain homeostasis of the central nervous system at all levels of organisation, including homeostasis of ions, pH and neurotransmitters; supplying neurones with metabolic substrates; supporting oligodendrocytes and axons; regulating synaptogenesis, neurogenesis, and formation and maintenance of the blood-brain barrier; contributing to operation of the glymphatic system; and regulation of systemic homeostasis being central chemosensors for oxygen, CO2 and Na+. Their basic physiological features show a lack of electrical excitability (inapt to produce action potentials), but display instead a rather active excitability based on variations in cytosolic concentrations of Ca2+ and Na+. It is expression of neurotransmitter receptors, pumps and transporters at their plasmalemma, along with transports on the endoplasmic reticulum and mitochondria that exquisitely regulate the cytosolic levels of these ions, the fluctuation of which underlies most, if not all, astroglial homeostatic functions.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Baoman Li
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Caterina Scuderi
- Department of Physiology and Pharmacology "Vittorio Erspamer", SAPIENZA University of Rome, Rome, Italy
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10
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Development of the hypersecretory phenotype in the population of adrenal chromaffin cells from prehypertensive SHRs. Pflugers Arch 2021; 473:1775-1793. [PMID: 34510285 DOI: 10.1007/s00424-021-02614-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 10/20/2022]
Abstract
The hypersecretory phenotype of adrenal chromaffin cells (CCs) from early spontaneously hypertensive rats (SHRs) mainly results from enhanced Ca2+-induced Ca2+-release (CICR). A key question is if these abnormalities can be traced to the prehypertensive stage. Spontaneous and stimulus-induced catecholamine exocytosis, intracellular Ca2+ signals, and dense-core granule size and density were examined in CCs from prehypertensive and hypertensive SHRs and compared with age-matched Wistar-Kyoto rats (WKY). During the prehypertensive stage, the depolarization-elicited catecholamine exocytosis was ~ 2.9-fold greater in SHR than in WKY CCs. Interestingly, in half of CCs the exocytosis was indistinguishable from WKY CCs, while it was between 3- and sixfold larger in the other half. Likewise, caffeine-induced exocytosis was ~ twofold larger in prehypertensive SHR. Accordingly, depolarization and caffeine application elicited [Ca2+]i rises ~ 1.5-fold larger in prehypertensive SHR than in WKY CCs. Ryanodine reduced the depolarization-induced secretion in prehypertensive SHR by 57%, compared to 14% in WKY CCs, suggesting a greater contribution of intracellular Ca2+ release to exocytosis. In SHR CCs, the mean spike amplitude and charge per spike were significantly larger than in WKY CCs, regardless of age and stimulus type. This difference in granule content could explain in part the enhanced exocytosis in SHR CCs. However, electron microscopy did not reveal significant differences in granule size between SHRs and WKY rats' adrenal medulla. Nonetheless, preSHR and hypSHR display 63% and 82% more granules than WKY, which could explain in part the enhanced catecholamine secretion. The mechanism responsible for the heterogeneous population of prehypertensive SHR CCs and the bias towards secreting more medium and large granules remains unexplained.
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11
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Ca 2+ handling at the mitochondria-ER contact sites in neurodegeneration. Cell Calcium 2021; 98:102453. [PMID: 34399235 DOI: 10.1016/j.ceca.2021.102453] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/03/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022]
Abstract
Mitochondria-endoplasmic reticulum (ER) contact sites (MERCS) are morpho-functional units, formed at the loci of close apposition of the ER-forming endomembrane and outer mitochondrial membrane (OMM). These sites contribute to fundamental cellular processes including lipid biosynthesis, autophagy, apoptosis, ER-stress and calcium (Ca2+) signalling. At MERCS, Ca2+ ions are transferred from the ER directly to mitochondria through a core protein complex composed of inositol-1,4,5 trisphosphate receptor (InsP3R), voltage-gated anion channel 1 (VDAC1), mitochondrial calcium uniporter (MCU) and adaptor protein glucose-regulated protein 75 (Grp75); this complex is regulated by several associated proteins. Deregulation of ER-mitochondria Ca2+ transfer contributes to pathogenesis of neurodegenerative and other diseases. The efficacy of Ca2+ transfer between ER and mitochondria depends on the protein composition of MERCS, which controls ER-mitochondria interaction regulating, for example, the transversal distance between ER membrane and OMM and the extension of the longitudinal interface between ER and mitochondria. These parameters are altered in neurodegeneration. Here we overview the ER and mitochondrial Ca2+ homeostasis, the composition of ER-mitochondrial Ca2+ transfer machinery and alterations of the ER-mitochondria Ca2+ transfer in three major neurodegenerative diseases: motor neurone diseases, Parkinson disease and Alzheimer's disease.
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12
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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13
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Martínez-Ramírez C, Gil-Gómez I, G de Diego AM, García AG. Acute reversible SERCA blockade facilitates or blocks exocytosis, respectively in mouse or bovine chromaffin cells. Pflugers Arch 2021; 473:273-286. [PMID: 33108514 DOI: 10.1007/s00424-020-02483-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/03/2020] [Accepted: 10/20/2020] [Indexed: 11/29/2022]
Abstract
Pre-blockade of the sarco-endoplasmic reticulum (ER) calcium ATPase (SERCA) with irreversible thapsigargin depresses exocytosis in adrenal bovine chromaffin cells (BCCs). Distinct expression of voltage-dependent Ca2+-channel subtypes and of the Ca2+-induced Ca2+ release (CICR) mechanism in BCCs versus mouse chromaffin cells (MCCs) has been described. We present a parallel study on the effects of the acute SERCA blockade with reversible cyclopizonic acid (CPA), to repeated pulsing with acetylcholine (ACh) at short (15 s) and long intervals (60 s) at 37 °C, allowing the monitoring of the initial size of a ready-release vesicle pool (RRP) and its depletion and recovery in subsequent stimuli. We found (i) strong depression of exocytosis upon ACh pulsing at 15-s intervals and slower depression at 60-s intervals in both cell types; (ii) facilitation of exocytosis upon acute SERCA inhibition, with back to depression upon CPA washout in MCCs; (iii) blockade of exocytosis upon acute SERCA inhibition and pronounced rebound of exocytosis upon CPA washout in BCCs; (iv) basal [Ca2+]c elevation upon stimulation with ACh at short intervals (but not at long intervals) in both cell types; and (v) augmentation of basal [Ca2+]c and inhibition of peak [Ca2+]c amplitude upon CPA treatment in both cell types, with milder effects upon stimulation at 60-s intervals. These results are compatible with the view that while in MCCs the uptake of Ca2+ via SERCA contributes to the mitigation of physiological ACh triggered secretion, in BCCs the uptake of Ca2+ into the ER facilitates such responses likely potentiating a Ca2+-induced Ca2+ release mechanism. These drastic differences in the regulation of ACh-triggered secretion at 37 °C may help to understand different patterns of the regulation of exocytosis by the circulation of Ca2+ at a functional ER Ca2+ store.
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Affiliation(s)
- Carmen Martínez-Ramírez
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain
- Departamento de Farmacología, Universidad Autónoma de Madrid, Madrid, Spain
- Fundación Teófilo Hernando, Parque científico de Madrid, Madrid, Spain
| | - Irene Gil-Gómez
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain
- Departamento de Farmacología, Universidad Autónoma de Madrid, Madrid, Spain
- Fundación Teófilo Hernando, Parque científico de Madrid, Madrid, Spain
| | - Antonio M G de Diego
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain.
- Departamento de Farmacología, Universidad Autónoma de Madrid, Madrid, Spain.
- Fundación Teófilo Hernando, Parque científico de Madrid, Madrid, Spain.
- Instituto de Investigación Sanitaria del Hospital de La Princesa, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
- DNS Neuroscience, Instituto Teófilo Hernando, Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Antonio G García
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain
- Departamento de Farmacología, Universidad Autónoma de Madrid, Madrid, Spain
- Fundación Teófilo Hernando, Parque científico de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital de La Princesa, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- DNS Neuroscience, Instituto Teófilo Hernando, Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain
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Abstract
Neuropeptides are important for regulating numerous neural functions and behaviors. Release of neuropeptides requires long-lasting, high levels of cytosolic Ca2+ However, the molecular regulation of neuropeptide release remains to be clarified. Recently, Stac3 was identified as a key regulator of L-type Ca2+ channels (CaChs) and excitation-contraction coupling in vertebrate skeletal muscles. There is a small family of stac genes in vertebrates with other members expressed by subsets of neurons in the central nervous system. The function of neural Stac proteins, however, is poorly understood. Drosophila melanogaster contain a single stac gene, Dstac, which is expressed by muscles and a subset of neurons, including neuropeptide-expressing motor neurons. Here, genetic manipulations, coupled with immunolabeling, Ca2+ imaging, electrophysiology, and behavioral analysis, revealed that Dstac regulates L-type CaChs (Dmca1D) in Drosophila motor neurons and this, in turn, controls the release of neuropeptides.
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15
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Hernández-Cruz A. Reversible interruption of ER Ca 2+ uptake inversely affects ACh-elicited exocytosis in mouse and bovine chromaffin cells. Pflugers Arch 2020; 473:133-134. [PMID: 33108515 DOI: 10.1007/s00424-020-02485-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Arturo Hernández-Cruz
- Instituto de Fisiología Celular, Departamento de Neurociencia Cognitiva and Laboratorio Nacional de Canalopatías, Universidad Nacional Autónoma de México, CP 04510, México City CDMX, México.
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16
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Panes JD, Godoy PA, Silva-Grecchi T, Celis MT, Ramirez-Molina O, Gavilan J, Muñoz-Montecino C, Castro PA, Moraga-Cid G, Yévenes GE, Guzmán L, Salisbury JL, Trushina E, Fuentealba J. Changes in PGC-1α/SIRT1 Signaling Impact on Mitochondrial Homeostasis in Amyloid-Beta Peptide Toxicity Model. Front Pharmacol 2020; 11:709. [PMID: 32523530 PMCID: PMC7261959 DOI: 10.3389/fphar.2020.00709] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/29/2020] [Indexed: 01/16/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive impairment that increasingly afflicts the elderly population. Soluble oligomers (AβOs) has been implicated in AD pathogenesis: however, the molecular events underlying a role for Aβ are not well understood. We studied the effects of AβOs on mitochondrial function and on key proteins that regulate mitochondrial dynamics and biogenesis in hippocampal neurons and PC-12 cells. We find that AβOs treatment caused a reduction in total Mfn1 after a 2 h exposure (42 ± 11%); while DRP1 increased at 1 and 2 h (205 ± 22% and 198 ± 27%, respectively), correlating to changes in mitochondrial morphology. We also observed that SIRT1 levels were reduced after acute and chronic AβOs treatment (68 ± 7% and 77 ± 6%, respectively); while PGC-1α levels were reduced with the same time treatments (68 ± 8% and 67 ± 7%, respectively). Interestingly, we found that chronic treatment with AβOs increased the levels of pSIRT1 (24 h: 157 ± 18%), and we observed changes in the PGC-1α and p-SIRT1 nucleus/cytosol ratio and SIRT1-PGC-1α interaction pattern after chronic exposure to AβOs. Our data suggest that AβOs induce important changes in the level and localization of mitochondrial proteins related with the loss of mitochondrial function that are mediated by a fast and sustained SIRT1/PGC-1α complex disruption promoting a “non-return point” to an irreversible synaptic failure and neuronal network disconnection.
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Affiliation(s)
- Jessica D Panes
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Pamela A Godoy
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Tiare Silva-Grecchi
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - María T Celis
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Oscar Ramirez-Molina
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Javiera Gavilan
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Carola Muñoz-Montecino
- Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Patricio A Castro
- Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Gustavo Moraga-Cid
- Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Gonzalo E Yévenes
- Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Leonardo Guzmán
- Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | | | - Eugenia Trushina
- Neurology Research, Mayo Clinic Foundation, Rochester, MN, United States
| | - Jorge Fuentealba
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile.,Center for Advanced Research on Biomedicine (CIAB-UdeC), Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
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17
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Direct monitoring of ER Ca 2+ dynamics reveals that Ca 2+ entry induces ER-Ca 2+ release in astrocytes. Pflugers Arch 2020; 472:439-448. [PMID: 32246199 DOI: 10.1007/s00424-020-02364-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/29/2020] [Accepted: 03/12/2020] [Indexed: 12/23/2022]
Abstract
Excitability in astroglia is controlled by Ca2+ fluxes from intracellular organelles, mostly from the endoplasmic reticulum (ER). Astrocytic ER possesses inositol 1,4,5-trisphosphate receptors (InsP3R) that can be activated upon stimulation through a vast number of metabotropic G-protein-coupled receptors. By contrast, the role of Ca2+-gated Ca2+ release channels is less explored in astroglia. Here we address this process by monitoring Ca2+ dynamics directly in the cytosol and the ER of astroglial cells. Cultured astrocytes exhibited spontaneous and high-K-evoked cytosolic Ca2+ transients, both of them reversibly abolished by external Ca2+ removal, addition of plasma membrane channel blockers or ER Ca2+ depletion with SERCA inhibitors. Resting astrocyte [Ca2+]ER averaged 400 μM and maximal stimulation with ATP provoked a complete and reversible ER discharge. Direct monitoring of Ca2+ in the lumen of ER showed that high-K induced a Ca2+ release from the ER, and its amplitude was proportional to the [K]. Furthermore, by combining the low affinity GAP3 indicator targeted to the ER with the high affinity cytosolic Rhod-2, we simultaneously imaged ER- and cytosolic-Ca2+ signals, in astrocytes in culture and in situ. Plasma membrane Ca2+ entry triggered a fast ER Ca2+ release coordinated with an increase in cytosolic Ca2+. Thus, we identify a Ca2+-induced Ca2+-release (CICR) mechanism that is likely to participate in spontaneous astroglial oscillations, providing a graded amplification of the cytosolic Ca2+ signal.
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18
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Moya‐Díaz J, Bayonés L, Montenegro M, Cárdenas AM, Koch H, Doi A, Marengo FD. Ca 2+ -independent and voltage-dependent exocytosis in mouse chromaffin cells. Acta Physiol (Oxf) 2020; 228:e13417. [PMID: 31769918 DOI: 10.1111/apha.13417] [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: 03/13/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/11/2022]
Abstract
AIM It is widely accepted that the exocytosis of synaptic and secretory vesicles is triggered by Ca2+ entry through voltage-dependent Ca2+ channels. However, there is evidence of an alternative mode of exocytosis induced by membrane depolarization but lacking Ca2+ current and intracellular Ca2+ increase. In this work we investigated if such a mechanism contributes to secretory vesicle exocytosis in mouse chromaffin cells. METHODS Exocytosis was evaluated by patch-clamp membrane capacitance measurements, carbon fibre amperometry and TIRF. Cytosolic Ca2+ was estimated using epifluorescence microscopy and fluo-8 (salt form). RESULTS Cells stimulated by brief depolatizations in absence of extracellular Ca+2 show moderate but consistent exocytosis, even in presence of high cytosolic BAPTA concentration and pharmacological inhibition of Ca+2 release from intracellular stores. This exocytosis is tightly dependent on membrane potential, is inhibited by neurotoxin Bont-B (cleaves the v-SNARE synaptobrevin), is very fast (saturates with time constant <10 ms), it is followed by a fast endocytosis sensitive to the application of an anti-dynamin monoclonal antibody, and recovers after depletion in <5 s. Finally, this exocytosis was inhibited by: (i) ω-agatoxin IVA (blocks P/Q-type Ca2+ channel gating), (ii) in cells from knock-out P/Q-type Ca2+ channel mice, and (iii) transfection of free synprint peptide (interferes in P/Q channel-exocytic proteins association). CONCLUSION We demonstrated that Ca2+ -independent and voltage-dependent exocytosis is present in chromaffin cells. This process is tightly coupled to membrane depolarization, and is able to support secretion during action potentials at low basal rates. P/Q-type Ca2+ channels can operate as voltage sensors of this process.
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Affiliation(s)
- José Moya‐Díaz
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Mauricio Montenegro
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Henner Koch
- Center for Integrative Brain Research Seattle Children's Research Institute Seattle WA USA
- Department of Neurology and Epileptology Hertie‐Institute for Clinical Brain ResearchUniversity of Tübingen Tübingen Germany
| | - Atsushi Doi
- Department of Rehabilitation Graduate School of Health Science Kumamoto Health Science University Kumamoto Japan
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
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19
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Molecular basis for allosteric regulation of the type 2 ryanodine receptor channel gating by key modulators. Proc Natl Acad Sci U S A 2019; 116:25575-25582. [PMID: 31792195 PMCID: PMC6926060 DOI: 10.1073/pnas.1914451116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
As a switch for the release of Ca2+ from the sarco(endo)plasmic reticulum of cardiomyocytes, the type 2 ryanodine receptor (RyR2) is subject to sophisticated regulation by a broad spectrum of modulators. Dysregulation of RyR2-mediated Ca2+ release is linked to life-threatening cardiac arrhythmias. The regulatory mechanism of RyR2 by key modulators, such as Ca2+, FKBP12.6, ATP, and caffeine, remains unclear. This study provides important insights into the long-range allosteric regulation of RyR2 channel gating by these modulators and serves as an important framework for mechanistic understanding of the regulation of this key player in the excitation–contraction coupling of cardiac muscles. The type 2 ryanodine receptor (RyR2) is responsible for releasing Ca2+ from the sarcoplasmic reticulum of cardiomyocytes, subsequently leading to muscle contraction. Here, we report 4 cryo-electron microscopy (cryo-EM) structures of porcine RyR2 bound to distinct modulators that, together with our published structures, provide mechanistic insight into RyR2 regulation. Ca2+ alone induces a contraction of the central domain that facilitates the dilation of the S6 bundle but is insufficient to open the pore. The small-molecule agonist PCB95 helps Ca2+ to overcome the barrier for opening. FKBP12.6 induces a relaxation of the central domain that decouples it from the S6 bundle, stabilizing RyR2 in a closed state even in the presence of Ca2+ and PCB95. Although the channel is open when PCB95 is replaced by caffeine and adenosine 5′-triphosphate (ATP), neither of the modulators alone can sufficiently counter the antagonistic effect to open the channel. Our study marks an important step toward mechanistic understanding of the sophisticated regulation of this key channel whose aberrant activity engenders life-threatening cardiac disorders.
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Carbone E, Borges R, Eiden LE, García AG, Hernández‐Cruz A. Chromaffin Cells of the Adrenal Medulla: Physiology, Pharmacology, and Disease. Compr Physiol 2019; 9:1443-1502. [DOI: 10.1002/cphy.c190003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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21
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Bagalkot TR, Leblanc N, Craviso GL. Stimulation or Cancellation of Ca 2+ Influx by Bipolar Nanosecond Pulsed Electric Fields in Adrenal Chromaffin Cells Can Be Achieved by Tuning Pulse Waveform. Sci Rep 2019; 9:11545. [PMID: 31395918 PMCID: PMC6687888 DOI: 10.1038/s41598-019-47929-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 07/26/2019] [Indexed: 12/30/2022] Open
Abstract
Exposing adrenal chromaffin cells to single 150 to 400 ns electric pulses triggers a rise in intracellular Ca2+ ([Ca2+]i) that is due to Ca2+ influx through voltage-gated Ca2+ channels (VGCC) and plasma membrane electropores. Immediate delivery of a second pulse of the opposite polarity in which the duration and amplitude were the same as the first pulse (a symmetrical bipolar pulse) or greater than the first pulse (an asymmetrical bipolar pulse) had a stimulatory effect, evoking larger Ca2+ responses than the corresponding unipolar pulse. Progressively decreasing the amplitude of the opposite polarity pulse while also increasing its duration converted stimulation to attenuation, which reached a maximum of 43% when the positive phase was 150 ns at 3.1 kV/cm, and the negative phase was 800 ns at 0.2 kV/cm. When VGCCs were blocked, Ca2+ responses evoked by asymmetrical and even symmetrical bipolar pulses were significantly reduced relative to those evoked by the corresponding unipolar pulse under the same conditions, indicating that attenuation involved mainly the portion of Ca2+ influx attributable to membrane electropermeabilization. Thus, by tuning the shape of the bipolar pulse, Ca2+ entry into chromaffin cells through electropores could be attenuated while preserving Ca2+ influx through VGCCs.
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Affiliation(s)
- Tarique R Bagalkot
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA.
| | - Normand Leblanc
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Gale L Craviso
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
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22
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de Pascual R, Álvarez-Ortego N, de Los Ríos C, Jacob-Mazariego G, García AG. Tetrabenazine Facilitates Exocytosis by Enhancing Calcium-Induced Calcium Release through Ryanodine Receptors. J Pharmacol Exp Ther 2019; 371:219-230. [PMID: 31209099 DOI: 10.1124/jpet.119.256560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/04/2019] [Indexed: 11/22/2022] Open
Abstract
Vesicular monoamine transporter-2 is expressed in the presynaptic secretory vesicles membrane in the brain. Its blockade by tetrabenazine (TBZ) causes depletion of dopamine at striatal basal ganglia; this is the mechanism underlying its long-standing use in the treatment of Huntington's disease. In the frame of a project aimed at investigating the kinetics of exocytosis from vesicles with partial emptying of their neurotransmitter, we unexpectedly found that TBZ facilitates exocytosis; thus, we decided to characterize such effect. We used bovine chromaffin cells (BCCs) challenged with repeated pulses of high K+ Upon repeated K+ pulsing, the exocytotic catecholamine release responses were gradually decaying. However, when cells were exposed to TBZ, responses were mildly augmented and decay rate delayed. Facilitation of exocytosis was not due to Ca2+ entry blockade through voltage-activated calcium channels (VACCs) because, in fact, TBZ mildly blocked the whole-cell Ca2+ current. However, TBZ mimicked the facilitatory effects of exocytosis elicited by BayK8644 (L-subtype VACC agonist), an effect blocked by nifedipine (VACC antagonist). On the basis that TBZ augmented the secretory responses to caffeine (but not those of histamine), we monitored its effects on cytosolic Ca2+ elevations ([Ca2+]c) triggered by caffeine or histamine. While the responses to caffeine were augmented twice by TBZ, those of histamine were unaffected; the same happened in rat cortical neurons. Hence, we hypothesize that TBZ facilitates exocytosis by increasing Ca2+ release through the endoplasmic reticulum ryanodine receptor channel (RyR). Confirming this hypothesis are docking results, showing an interaction of TBZ with RyRs. This is consonant with the existence of a healthy Ca2+-induced-Ca2+-release mechanism in BCCs. SIGNIFICANCE STATEMENT: A novel mechanism of action for tetrabenazine (TBZ), a drug used in the therapy of Huntington's disease (HD), is described here. Such mechanism consists of facilitation by combining TBZ with the ryanodine receptor of the endoplasmic reticulum, thereby increasing Ca2+-induced Ca2+ release. This novel mechanism should be taken into account when considering the efficacy and/or safety of TBZ in the treatment of chorea associated with HD and other disorders. Additionally, it could be of interest in the development of novel medicines to treat these pathological conditions.
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Affiliation(s)
- Ricardo de Pascual
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Nuria Álvarez-Ortego
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristóbal de Los Ríos
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Gema Jacob-Mazariego
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
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Ultrashort nanosecond electric pulses evoke heterogeneous patterns of Ca 2+ release from the endoplasmic reticulum of adrenal chromaffin cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1180-1188. [PMID: 30986385 DOI: 10.1016/j.bbamem.2019.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 01/19/2023]
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24
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Caffeine chelates calcium in the lumen of the endoplasmic reticulum. Biochem J 2018; 475:3639-3649. [PMID: 30389846 DOI: 10.1042/bcj20180532] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/14/2018] [Accepted: 11/01/2018] [Indexed: 12/29/2022]
Abstract
Cytosolic Ca2+ signals are often amplified by massive calcium release from the endoplasmic reticulum (ER). This calcium-induced calcium release (CICR) occurs by activation of an ER Ca2+ channel, the ryanodine receptor (RyR), which is facilitated by both cytosolic- and ER Ca2+ levels. Caffeine sensitizes RyR to Ca2+ and promotes ER Ca2+ release at basal cytosolic Ca2+ levels. This outcome is frequently used as a readout for the presence of CICR. By monitoring ER luminal Ca2+ with the low-affinity genetic Ca2+ probe erGAP3, we find here that application of 50 mM caffeine rapidly reduces the Ca2+ content of the ER in HeLa cells by ∼50%. Interestingly, this apparent ER Ca2+ release does not go along with the expected cytosolic Ca2+ increase. These results can be explained by Ca2+ chelation by caffeine inside the ER. Ca2+-overloaded mitochondria also display a drop of the matrix Ca2+ concentration upon caffeine addition. In contrast, in the cytosol, with a low free Ca2+ concentration (10-7 M), no chelation is observed. Expression of RyR3 sensitizes the responses to caffeine with effects both in the ER (increase in Ca2+ release) and in the cytosol (increase in Ca2+ peak) at low caffeine concentrations (0.3-1 mM) that have no effects in control cells. Our results illustrate the fact that simultaneous monitoring of both cytosolic- and ER Ca2+ are necessary to understand the action of caffeine and raise concerns against the use of high concentrations of caffeine as a readout of the presence of CICR.
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25
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Félix-Martínez GJ, Gil A, Segura J, Villanueva J, Gutíerrez LM. Modeling the influence of co-localized intracellular calcium stores on the secretory response of bovine chromaffin cells. Comput Biol Med 2018; 100:165-175. [PMID: 30015013 DOI: 10.1016/j.compbiomed.2018.06.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 11/19/2022]
Abstract
Catecholamines secretion from chromaffin cells is mediated by a Ca2+-dependent process in the submembrane space where the exocytotic machinery is located and high-Ca2+ microdomains (HCMDs) are formed by the coordinated activity of a functional triad composed of Ca2+ channels, endoplasmic reticulum (ER) and mitochondria. It has been observed experimentally that subpopulations of cortical mitochondria and ER associate to secretory sites in bovine chromaffin cells. Here, we study the effect of the geometrical distribution of the co-localized cortical organelles both in the formation of HCMDs in the vicinity of Ca2+ channels and on the secretory activity of bovine chromaffin cells in response to a single voltage pulse. Our simulations indicate that co-localized organelles have a dual role in the formation of HCMDs, having, on the one hand, an amplification effect due to the Ca2+-induced Ca2+-release mechanism from the ER and, on the other, acting as physical barriers to Ca2+ diffusion. In addition, our simulations suggest that the increased levels of Ca2+ in the microdomain enhances the secretion of the vesicles co-localized to the Ca2+ channels. As a whole, our results support the idea that the functional triads formed by Ca2+ channels, subplasmalemma ER and mitochondria have a positive effect on the secretion of catecholamines in bovine chromaffin cells.
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Affiliation(s)
- Gerardo J Félix-Martínez
- Depto. de Matemática Aplicada y Ciencias de la Computación, Universidad de Cantabria, 39005, Santander, Spain; Depto. de Ingeniería Eléctrica, Universidad Autónoma Metropolitana, 09340, Mexico City, Mexico.
| | - Amparo Gil
- Depto. de Matemática Aplicada y Ciencias de la Computación, Universidad de Cantabria, 39005, Santander, Spain.
| | - Javier Segura
- Depto. de Matemáticas, Estadística y Computación, Universidad de Cantabria, 39005, Santander, Spain.
| | - José Villanueva
- Instituto de Neurociencias, Centro Mixto Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, 03550, Alicante, Spain.
| | - Luis M Gutíerrez
- Instituto de Neurociencias, Centro Mixto Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, 03550, Alicante, Spain.
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26
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Hydrogen sulphide facilitates exocytosis by regulating the handling of intracellular calcium by chromaffin cells. Pflugers Arch 2018; 470:1255-1270. [DOI: 10.1007/s00424-018-2147-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 04/10/2018] [Accepted: 04/17/2018] [Indexed: 01/09/2023]
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27
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Musial DC, Bomfim GH, Arranz-Tagarro JA, Méndez-López I, Miranda-Ferreira R, Jurkiewicz A, Jurkiewicz NH, García AG, Padín JF. Altered mitochondrial function, calcium signaling, and catecholamine release in chromaffin cells of diabetic and SHR rats. Eur J Pharmacol 2017; 815:416-426. [DOI: 10.1016/j.ejphar.2017.09.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 09/12/2017] [Accepted: 09/28/2017] [Indexed: 11/25/2022]
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28
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Calcium signaling and cell cycle: Progression or death. Cell Calcium 2017; 70:3-15. [PMID: 28801101 DOI: 10.1016/j.ceca.2017.07.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/23/2017] [Accepted: 07/23/2017] [Indexed: 12/12/2022]
Abstract
Cytosolic Ca2+ concentration levels fluctuate in an ordered manner along the cell cycle, in line with the fact that Ca2+ is involved in the regulation of cell proliferation. Cell proliferation should be an error-free process, yet is endangered by mistakes. In fact, a complex network of proteins ensures that cell cycle does not progress until the previous phase has been successfully completed. Occasionally, errors occur during the cell cycle leading to cell cycle arrest. If the error is severe, and the cell cycle checkpoints work perfectly, this results into cellular demise by activation of apoptotic or non-apoptotic cell death programs. Cancer is characterized by deregulated proliferation and resistance against cell death. Ca2+ is a central key to these phenomena as it modulates signaling pathways that control oncogenesis and cancer progression. Here, we discuss how Ca2+ participates in the exogenous and endogenous signals controlling cell proliferation, as well as in the mechanisms by which cells die if irreparable cell cycle damage occurs. Moreover, we summarize how Ca2+ homeostasis remodeling observed in cancer cells contributes to deregulated cell proliferation and resistance to cell death. Finally, we discuss the possibility to target specific components of Ca2+ signal pathways to obtain cytostatic or cytotoxic effects.
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29
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Altered mitochondrial function, capacitative calcium entry and contractions in the aorta of hypertensive rats. J Hypertens 2017; 35:1594-1608. [PMID: 28403042 DOI: 10.1097/hjh.0000000000001360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE It has been suggested that Ca entry through store-operated Ca channels (SOCs) is regulated by a dynamic interplay between the endoplasmic reticulum Ca stores and the mitochondria. These relationships drive the activation and inactivation of SOCs, yet it remains unclear whether this regulation of SOCs by mitochondria is altered in the aorta of spontaneously hypertensive rats (SHRs). METHODS We performed a thorough study of the mitochondrial membrane potential, the ability of mitochondria to deal with cytosolic Ca, capacitative Ca entry (CCE), and stromal interaction molecule 1 (STIM1) and calcium release-activated calcium modulator 1 (orai1) protein expression, as well as the contractile capacity of aortic rings, in normotensive Wistar Kyoto rats (WKYs) and SHRs. RESULTS Changes were observed in aortic tissue and cultured vascular smooth muscle cells isolated from SHRs relative to WKYs, including more depolarized mitochondria, stronger CCE upon the addition of Ca, larger cytosolic Ca transients (cytosolic Ca concentration) or aortic ring contraction elicited by endoplasmic reticulum depletion and a significant increase in STIM1 protein expression but not of orai1. CONCLUSION These results suggest that the impaired Ca buffering capacity of partially depolarized mitochondria dysregulates CCE, leading to overfilling of the endoplasmic reticulum Ca store through enhanced STIM1/orai1 interactions and an increase in aorta contractions in SHRs. Thus, understanding the implications of the alterations to STIM1/orai1, and their relationship to mitochondria, may aid drug development and therapeutic strategies to treat hypertension, as well as its long-term sequelae in poorly controlled patients.
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30
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Alonso MT, Rodríguez-Prados M, Navas-Navarro P, Rojo-Ruiz J, García-Sancho J. Using aequorin probes to measure Ca 2+ in intracellular organelles. Cell Calcium 2017; 64:3-11. [PMID: 28214023 DOI: 10.1016/j.ceca.2017.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/11/2017] [Indexed: 11/28/2022]
Abstract
Aequorins are excellent tools for measuring intra-organellar Ca2+ and assessing its role in physiological and pathological functions. Here we review targeting strategies to express aequorins in various organelles. We address critical topics such as probe affinity tuning as well as normalization and calibration of the signal. We also focus on bioluminescent Ca2+ imaging in nucleus or mitochondria of living cells. Finally, recent advances with a new chimeric GFP-aequorin protein (GAP), which can be used either as luminescent or fluorescent Ca2+ probe, are presented. GAP is robustly expressed in transgenic flies and mice, where it has proven to be a suitable Ca2+ indicator for monitoring physiological Ca2+ signaling ex vivo and in vivo.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
| | - Macarena Rodríguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
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31
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Alonso MT, Rojo-Ruiz J, Navas-Navarro P, Rodríguez-Prados M, García-Sancho J. Measuring Ca 2+ inside intracellular organelles with luminescent and fluorescent aequorin-based sensors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:894-899. [PMID: 27939433 DOI: 10.1016/j.bbamcr.2016.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/05/2016] [Accepted: 12/06/2016] [Indexed: 02/06/2023]
Abstract
GFP-Aequorin Protein (GAP) can be used to measure [Ca2+] inside intracellular organelles, both by luminescence and by fluorescence. The low-affinity variant GAP3 is adequate for ratiometric imaging in the endoplasmic reticulum and Golgi apparatus, and it can be combined with conventional synthetic indicators for simultaneous measurements of cytosolic Ca2+. GAP is bioorthogonal as it does not have mammalian homologues, and it is robust and functionally expressed in transgenic flies and mice, where it can be used for Ca2+ measurements ex vivo and in vivo to explore animal models of health and disease. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain.
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Macarena Rodríguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain.
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32
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Calvo-Gallardo E, López-Gil Á, Méndez-López I, Martínez-Ramírez C, Padín JF, García AG. Faster kinetics of quantal catecholamine release in mouse chromaffin cells stimulated with acetylcholine, compared with other secretagogues. J Neurochem 2016; 139:722-736. [PMID: 27649809 DOI: 10.1111/jnc.13849] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/16/2016] [Accepted: 08/31/2016] [Indexed: 11/27/2022]
Abstract
Adrenal chromaffin cells (CCs) have been used extensively in studies aimed at revealing the intricacies of the Ca2+ -dependent early and late steps of regulated exocytosis. They have also served as invaluable models to study the kinetics of single-vesicle exocytotic events to infer the characteristics of opening and closing of the exocytotic fusion pore. We have here tested the hypothesis that stimulation at room temperature of CCs from mice C57BL/6 with physiological acetylcholine (ACh) and with other secretagogues (dimethylphenylpiperazinium, high K+ , muscarine, histamine, caffeine), alone or in combination, could trigger amperometric spike events with different kinetics. We found that mean secretory spike events in CCs stimulated with ACh had a fast rise rate of 25 pA/ms and a rapid decay time of 6.2 ms, with a small quantal size (0.31 pC). Surprisingly, these parameters considerably differed from those found in CCs stimulated with all other secretagogues that triggered secretory responses with spike events having smaller rise rates, longer decay times and higher quantal sizes. ACh spikes were unaltered by atropine but mitochondrial protonophore carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone markedly slowed down the rate rise and decay time, and augmented the quantal size of mean secretory events. We conclude that the physiological neurotransmitter ACh triggers a fast and efficient exocytotic response that cannot be mimicked by other secretagogues; such response is regulated by the mitochondrial circulation of calcium ions.
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Affiliation(s)
- Enrique Calvo-Gallardo
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ángela López-Gil
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iago Méndez-López
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Martínez-Ramírez
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Fernando Padín
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Servicio de Farmacología Clínica, Hospital Universitario de La Princesa, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Madrid, Spain
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33
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Regulation by L channels of Ca(2+)-evoked secretory responses in ouabain-treated chromaffin cells. Pflugers Arch 2016; 468:1779-92. [PMID: 27558258 DOI: 10.1007/s00424-016-1866-x] [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: 05/16/2016] [Revised: 07/21/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
It is known that the sustained depolarisation of adrenal medullary bovine chromaffin cells (BCCs) with high K(+) concentrations produces an initial sharp catecholamine release that subsequently fades off in spite depolarisation persists. Here, we have recreated a sustained depolarisation condition of BCCs by treating them with the Na(+)/K(+) ATPase blocker ouabain; in doing so, we searched experimental conditions that permitted the development of a sustained long-term catecholamine release response that could be relevant during prolonged stress. BCCs were perifused with nominal 0Ca(2+) solution, and secretion responses were elicited by intermittent application of short 2Ca(2+) pulses (Krebs-HEPES containing 2 mM Ca(2+)). These pulses elicited a biphasic secretory pattern with an initial 30-min period with secretory responses of increasing amplitude and a second 30-min period with steady-state, non-inactivating responses. The initial phase was not due to gradual depolarisation neither to gradual increases of the cytosolic calcium transients ([Ca(2+)]c) elicited by 2Ca(2+) pulses in BBCs exposed to ouabain; both parameters increased soon after ouabain addition. Νifedipine blocked these responses, and FPL64176 potentiated them, suggesting that they were triggered by Ca(2+) entry through non-inactivating L-type calcium channels. This was corroborated by nifedipine-evoked blockade of the L-type Ca(2+) channel current and the [Ca(2+)]c transients elicited by 2Ca(2+) pulses. Furthermore, the plasmalemmal Na(+)/Ca(2+) exchanger (NCX) blocker SEA0400 caused a mild inhibition followed by a large rebound increase of the steady-state secretory responses. We conclude that these two phases of secretion are mostly contributed by Ca(2+) entry through L calcium channels, with a minor contribution of Ca(2+) entry through the reverse mode of the NCX.
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34
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Navas-Navarro P, Rojo-Ruiz J, Rodriguez-Prados M, Ganfornina MD, Looger LL, Alonso MT, García-Sancho J. GFP-Aequorin Protein Sensor for Ex Vivo and In Vivo Imaging of Ca(2+) Dynamics in High-Ca(2+) Organelles. Cell Chem Biol 2016; 23:738-45. [PMID: 27291400 DOI: 10.1016/j.chembiol.2016.05.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/05/2016] [Accepted: 05/10/2016] [Indexed: 11/17/2022]
Abstract
Proper functioning of organelles such as the ER or the Golgi apparatus requires luminal accumulation of Ca(2+) at high concentrations. Here we describe a ratiometric low-affinity Ca(2+) sensor of the GFP-aequorin protein (GAP) family optimized for measurements in high-Ca(2+) concentration environments. Transgenic animals expressing the ER-targeted sensor allowed monitoring of Ca(2+) signals inside the organelle. The use of the sensor was demonstrated under three experimental paradigms: (1) ER Ca(2+) oscillations in cultured astrocytes, (2) ex vivo functional mapping of cholinergic receptors triggering ER Ca(2+) release in acute hippocampal slices from transgenic mice, and (3) in vivo sarcoplasmic reticulum Ca(2+) dynamics in the muscle of transgenic flies. Our results provide proof of the suitability of the new biosensors to monitor Ca(2+) dynamics inside intracellular organelles under physiological conditions and open an avenue to explore complex Ca(2+) signaling in animal models of health and disease.
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Affiliation(s)
- Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - Macarena Rodriguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - María Dolores Ganfornina
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - Loren L Looger
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain.
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), University of Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain.
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35
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Castellano-Muñoz M, Schnee ME, Ricci AJ. Calcium-induced calcium release supports recruitment of synaptic vesicles in auditory hair cells. J Neurophysiol 2015; 115:226-39. [PMID: 26510758 DOI: 10.1152/jn.00559.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 10/23/2015] [Indexed: 01/31/2023] Open
Abstract
Hair cells from auditory and vestibular systems transmit continuous sound and balance information to the central nervous system through the release of synaptic vesicles at ribbon synapses. The high activity experienced by hair cells requires a unique mechanism to sustain recruitment and replenishment of synaptic vesicles for continuous release. Using pre- and postsynaptic electrophysiological recordings, we explored the potential contribution of calcium-induced calcium release (CICR) in modulating the recruitment of vesicles to auditory hair cell ribbon synapses. Pharmacological manipulation of CICR with agents targeting endoplasmic reticulum calcium stores reduced both spontaneous postsynaptic multiunit activity and the frequency of excitatory postsynaptic currents (EPSCs). Pharmacological treatments had no effect on hair cell resting potential or activation curves for calcium and potassium channels. However, these drugs exerted a reduction in vesicle release measured by dual-sine capacitance methods. In addition, calcium substitution by barium reduced release efficacy by delaying release onset and diminishing vesicle recruitment. Together these results demonstrate a role for calcium stores in hair cell ribbon synaptic transmission and suggest a novel contribution of CICR in hair cell vesicle recruitment. We hypothesize that calcium entry via calcium channels is tightly regulated to control timing of vesicle fusion at the synapse, whereas CICR is used to maintain a tonic calcium signal to modulate vesicle trafficking.
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Affiliation(s)
- Manuel Castellano-Muñoz
- Department of Otolaryngology, Stanford University School of Medicine, Stanford, California; and
| | - Michael E Schnee
- Department of Otolaryngology, Stanford University School of Medicine, Stanford, California; and
| | - Anthony J Ricci
- Department of Otolaryngology, Stanford University School of Medicine, Stanford, California; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
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36
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Crespo-Castrillo A, Punzón E, de Pascual R, Maroto M, Padín JF, García-Álvarez I, Nanclares C, Ruiz-Pascual L, Gandía L, Fernández-Mayoralas A, García AG. Novel synthetic sulfoglycolipid IG20 facilitates exocytosis in chromaffin cells through the regulation of sodium channels. J Neurochem 2015; 135:880-96. [DOI: 10.1111/jnc.13357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/03/2015] [Accepted: 08/19/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Andrea Crespo-Castrillo
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Eva Punzón
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Ricardo de Pascual
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Departamento de Farmacología; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Marcos Maroto
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Juan Fernando Padín
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Departamento de Farmacología; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | | | - Carmen Nanclares
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Departamento de Farmacología; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Lucía Ruiz-Pascual
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | - Luis Gandía
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Departamento de Farmacología; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
| | | | - Antonio G. García
- Instituto Teófilo Hernando; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Departamento de Farmacología; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
- Servicio de Farmacología Clínica; Instituto de Investigación Sanitaria; Hospital Universitario de La Princesa; Madrid Spain
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Enhanced Ca2+-induced Ca2+ release from intracellular stores contributes to catecholamine hypersecretion in adrenal chromaffin cells from spontaneously hypertensive rats. Pflugers Arch 2015; 467:2307-23. [DOI: 10.1007/s00424-015-1702-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/02/2015] [Accepted: 03/08/2015] [Indexed: 01/09/2023]
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38
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Fernández-Morales JC, Fernando Padín J, Vestring S, Musial DC, de Diego AMG, García AG. Blockade by NNC 55-0396, mibefradil, and nickel of calcium and exocytotic signals in chromaffin cells: Implications for the regulation of hypoxia-induced secretion at early life. Eur J Pharmacol 2015; 751:1-12. [DOI: 10.1016/j.ejphar.2015.01.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 12/11/2022]
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Caffeine stimulates in vitro pituitary LH secretion in lipopolysaccharide-treated ewes. Reprod Biol 2015; 15:20-6. [DOI: 10.1016/j.repbio.2014.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/04/2014] [Accepted: 12/04/2014] [Indexed: 11/18/2022]
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Momboisse F, Olivares MJ, Báez-Matus X, Guerra MJ, Flores-Muñoz C, Sáez JC, Martínez AD, Cárdenas AM. Pannexin 1 channels: new actors in the regulation of catecholamine release from adrenal chromaffin cells. Front Cell Neurosci 2014; 8:270. [PMID: 25237296 PMCID: PMC4154466 DOI: 10.3389/fncel.2014.00270] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 08/20/2014] [Indexed: 11/13/2022] Open
Abstract
Chromaffin cells of the adrenal gland medulla synthesize and store hormones and peptides, which are released into the blood circulation in response to stress. Among them, adrenaline is critical for the fight-or-flight response. This neurosecretory process is highly regulated and depends on cytosolic [Ca2+]. By forming channels at the plasma membrane, pannexin-1 (Panx1) is a protein involved in many physiological and pathological processes amplifying ATP release and/or Ca2+ signals. Here, we show that Panx1 is expressed in the adrenal gland where it plays a role by regulating the release of catecholamines. In fact, inhibitors of Panx1 channels, such as carbenoxolone (Cbx) and probenecid, reduced the secretory activity induced with the nicotinic agonist 1,1-dimethyl-4-phenyl-piperazinium (DMPP, 50 μM) in whole adrenal glands. A similar inhibitory effect was observed in single chromaffin cells using Cbx or 10Panx1 peptide, another Panx1 channel inhibitors. Given that the secretory response depends on cytosolic [Ca2+] and Panx1 channels are permeable to Ca2+, we studied the possible implication of Panx1 channels in the Ca2+ signaling occurring during the secretory process. In support of this possibility, Panx1 channel inhibitors significantly reduced the Ca2+ signals evoked by DMPP in single chromaffin cells. However, the Ca2+ signals induced by caffeine in the absence of extracellular Ca2+ was not affected by Panx1 channel inhibitors, suggesting that this mechanism does not involve Ca2+ release from the endoplasmic reticulum. Conversely, Panx1 inhibitors significantly blocked the DMPP-induce dye uptake, supporting the idea that Panx1 forms functional channels at the plasma membrane. These findings indicate that Panx1 channels participate in the control the Ca2+ signal that triggers the secretory response of adrenal chromaffin cells. This mechanism could have physiological implications during the response to stress.
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Affiliation(s)
- Fanny Momboisse
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - María José Olivares
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - María José Guerra
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Carolina Flores-Muñoz
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Juan C Sáez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile ; Departamento de Fisiología, Pontifícia Universidad Católica de Chile Santiago, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
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Fernández-Morales JC, Padín JF, Arranz-Tagarro JA, Vestring S, García AG, de Diego AMG. Hypoxia-elicited catecholamine release is controlled by L-type as well as N/PQ types of calcium channels in rat embryo chromaffin cells. Am J Physiol Cell Physiol 2014; 307:C455-65. [PMID: 24990647 DOI: 10.1152/ajpcell.00101.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic conditions. This response depends on Ca(2+) entry through voltage-activated calcium channels (VACCs). We have investigated here three unresolved questions that concern this response in rat embryo chromaffin cells (ECCs): 1) the relative contribution of L (α1D, Cav1.3), N (α1B, Cav2.2), and PQ (α1A, Cav2.1) to the whole cell Ca(2+) current (ICa); 2) the relative contribution of L and N/PQ channels to the cytosolic Ca(2+) elevations triggered by hypoxia (Δ[Ca(2+)]c); and 3) the role of L and non-L high-VACCs in the regulation of the catecholamine surge occurring during prolonged (1 min) hypoxia exposure of ECCs. Nimodipine halved peak ICa and blocked 60% the total Ca(2+) entry during a 50-ms depolarizing pulse to 0 mV (QCa). Combined ω-agatoxin IVA plus ω-conotoxin GVIA (Aga/GVIA) blocked 30% of both ICa peak and QCa. This relative proportion of L- and non-L VACCs was corroborated by Western blot that indicated 55, 23, and 25% relative expression of L, N, and PQ VACCs. Exposure of ECCs to hypoxia elicited a mild but sustained Δ[Ca(2+)]c; the area of Δ[Ca(2+)]c was blocked 50% by nifedipine and 10% by Aga/GVIA. Exposure of ECCs to 1-min hypoxia elicited an initial transient burst of amperometric secretory spikes followed by scattered spikes along the time of cell exposure to hypoxia. This bulk response was blocked 85% by nimodipine and 35% by Aga/GVIA. Histograms on secretory spike frequency vs. time indicated a faster initial inactivation when Ca(2+) entry took place through N/PQ channels; more sustained secretion but at a lower rate was associated to Ca(2+) entry through L channels. The results suggest that the HIS response may initially be controlled by L and P/Q channels, but later on, N/PQ channels inactivate and the delayed HIS response is maintained at lower rate by slow-inactivating L channels.
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Affiliation(s)
- José-Carlos Fernández-Morales
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan-Fernando Padín
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan-Alberto Arranz-Tagarro
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Stefan Vestring
- Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Antonio G García
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain; and
| | - Antonio Miguel G de Diego
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain;
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Lukewich MK, Lomax AE. Endotoxemia enhances catecholamine secretion from male mouse adrenal chromaffin cells through an increase in Ca(2+) release from the endoplasmic reticulum. Endocrinology 2014; 155:180-92. [PMID: 24169560 DOI: 10.1210/en.2013-1623] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Enhanced epinephrine secretion from adrenal chromaffin cells (ACCs) is an important homeostatic response to severe systemic inflammation during sepsis. Evidence suggests that increased activation of ACCs by preganglionic sympathetic neurons and direct alterations in ACC function contribute to this response. However, the direct effects of sepsis on ACC function have yet to be characterized. We hypothesized that sepsis enhances epinephrine secretion from ACCs by increasing intracellular Ca(2+) signaling. Plasma epinephrine concentration was increased 5-fold in the lipopolysaccharide-induced endotoxemia model of sepsis compared with saline-treated control mice. Endotoxemia significantly enhanced stimulus-evoked epinephrine secretion from isolated ACCs in vitro. Carbon fiber amperometry revealed an increase in the number of secretory events during endotoxemia, without significant changes in spike amplitude, half-width, or quantal content. ACCs isolated up to 12 hours after the induction of endotoxemia exhibited larger stimulus-evoked Ca(2+) transients compared with controls. Similarly, ACCs from cecal ligation and puncture mice also exhibited enhanced Ca(2+) signaling. Although sepsis did not significantly affect ACC excitability or voltage-gated Ca(2+) currents, a 2-fold increase in caffeine (10 mM)-stimulated Ca(2+) transients was observed during endotoxemia. Depletion of endoplasmic reticulum Ca(2+) stores using cyclopiazonic acid (10 μM) abolished the effects of endotoxemia on catecholamine secretion from ACCs. These findings suggest that sepsis directly enhances catecholamine secretion from ACCs through an increase in Ca(2+) release from the endoplasmic reticulum. These alterations in ACC function are likely to amplify the effects of increased preganglionic sympathetic neuron activity to further enhance epinephrine levels during sepsis.
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Affiliation(s)
- Mark K Lukewich
- Departments of Biomedical and Molecular Sciences (M.K.L., A.E.L.) and Medicine, Gastrointestinal Diseases Research Unit (A.E.L.) and Centre for Neuroscience Studies (A.E.L.), Queen's University, Kingston, Ontario, Canada K7L 2V7
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Shou Q, Pan S, Tu J, Jiang J, Ling Y, Cai Y, Chen M, Wang D. Modulation effect of Smilax glabra flavonoids on ryanodine receptor mediated intracellular Ca2+ release in cardiomyoblast cells. JOURNAL OF ETHNOPHARMACOLOGY 2013; 150:389-392. [PMID: 23954280 DOI: 10.1016/j.jep.2013.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/23/2013] [Accepted: 08/06/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Smilax glabra rhizome, a plant material from Liliaceae family, is a widely used traditional Chinese medicine for anti-cardiac hypertrophy treatment. We have previously found that Smilax glabra flavonoids (SGF) exerted such anti-cardiac hypertrophy activity. However, the mechanism of this activity of SGF has not been clarified yet. MATERIALS AND METHODS This study was aimed to investigate the inhibitory role of SGF on intracellular Ca(2+) release in rat cardiomyoblast cells (H9C2). Intracellular Ca(2+) release was determined by Ca(2+) indicator fluorescence (fluo 4-AM) in H9C2 cell line. RESULTS SGF at concentrations of 0.25, 0.5, 1.0mg/ml significantly inhibited the phenylephrine or angiotensin II induced intracellular Ca(2+) release in a dose-dependent manner. Furthermore, SGF could also inhibit ryanodine receptor (RyR) agonist caffeine induced Ca(2+) release and phenylephrine (PE)-induced Ca(2+) release under the condition in which inositol trisphosphate (IP3) receptors were blocked with 2-Aminoethoxydiphenyl borate (2-APB). Nevertheless, SGF had no impact on PE-induced Ca(2+) release under the condition in which RyRs were blocked with tetracaine. CONCLUSIONS Our results suggest that the protective effects of SGF are mediated via targeting inhibition of RyR mediated intracellular Ca(2+) release.
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Affiliation(s)
- Qiyang Shou
- Experimental Animal Research Center, Zhejiang Chinese Medical University, Hangzhou 310053, China
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Ca2+ homeostasis in the endoplasmic reticulum measured with a new low-Ca2+-affinity targeted aequorin. Cell Calcium 2013; 54:37-45. [DOI: 10.1016/j.ceca.2013.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/27/2013] [Accepted: 04/04/2013] [Indexed: 11/18/2022]
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García-Sancho J. The coupling of plasma membrane calcium entry to calcium uptake by endoplasmic reticulum and mitochondria. J Physiol 2013; 592:261-8. [PMID: 23798493 DOI: 10.1113/jphysiol.2013.255661] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cross-talk between organelles and plasma membrane Ca(2+) channels is essential for modulation of the cytosolic Ca(2+) ([Ca(2+)]C) signals, but such modulation may differ among cells. In chromaffin cells Ca(2+) entry through voltage-operated channels induces calcium release from the endoplasmic reticulum (ER) that amplifies the signal. [Ca(2+)]C microdomains as high as 20-50 μm are sensed by subplasmalemmal mitochondria, which accumulate large amounts of Ca(2+) through the mitochondrial Ca(2+) uniporter (MCU). Mitochondria confine the high-Ca(2+) microdomains (HCMDs) to beneath the plasma membrane, where exocytosis of secretory vesicles happens. Cell core [Ca(2+)]C is much smaller (1-2 μm). By acting as a Ca(2+) sink, mitochondria stabilise the HCMD in space and time. In non-excitable HEK293 cells, activation of store-operated Ca(2+) entry, triggered by ER Ca(2+) emptying, also generated subplasmalemmal HCMDs, but, in this case, most of the Ca(2+) was taken up by the ER rather than by mitochondria. The smaller size of the [Ca(2+)]C peak in this case (about 2 μm) may contribute to this outcome, as the sarco-endoplasmic reticulum Ca(2+) ATPase has much higher Ca(2+) affinity than MCU. It is also possible that the relative positioning of organelles, channels and effectors, as well as cytoskeleton and accessory proteins plays an important role.
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Padín JF, Fernández-Morales JC, Olivares R, Vestring S, Arranz-Tagarro JA, Calvo-Gallardo E, de Pascual R, Gandía L, García AG. Plasmalemmal sodium-calcium exchanger shapes the calcium and exocytotic signals of chromaffin cells at physiological temperature. Am J Physiol Cell Physiol 2013; 305:C160-72. [PMID: 23596174 DOI: 10.1152/ajpcell.00016.2013] [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] [Indexed: 12/24/2022]
Abstract
The activity of the plasmalemmal Na(+)/Ca(2+) exchanger (NCX) is highly sensitive to temperature. We took advantage of this fact to explore here the effects of the NCX blocker KB-R7943 (KBR) at 22 and 37°C on the kinetics of Ca(2+) currents (ICa), cytosolic Ca(2+) ([Ca(2+)]c) transients, and catecholamine release from bovine chromaffin cells (BCCs) stimulated with high K(+), caffeine, or histamine. At 22°C, the effects of KBR on those parameters were meager or nil. However, at 37°C whereby the NCX is moving Ca(2+) at a rate fivefold higher than at 22°C, various of the effects of KBR were pronounced, namely: 1) no effects on ICa; 2) reduction of the [Ca(2+)]c transient amplitude and slowing down of its rate of clearance; 3) blockade of the K(+)-elicited quantal release of catecholamine; 4) blockade of burst catecholamine release elicited by K(+); 5) no effect on catecholamine release elicited by short K(+) pulses (1-2 s) and blockade of the responses produced by longer K(+) pulses (3-5 s); and 6) potentiation of secretion elicited by histamine or caffeine. Furthermore, the more selective NCX blocker SEA0400 also potentiated the secretory responses to caffeine. The results suggest that at physiological temperature the NCX substantially contributes to shaping the kinetics of [Ca(2+)]c transients and the exocytotic responses elicited by Ca(2+) entry through Ca(2+) channels as well as by Ca(2+) release from the endoplasmic reticulum.
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Fernández-Morales JC, Arranz-Tagarro JA, Calvo-Gallardo E, Maroto M, Padín JF, García AG. Stabilizers of neuronal and mitochondrial calcium cycling as a strategy for developing a medicine for Alzheimer's disease. ACS Chem Neurosci 2012; 3:873-83. [PMID: 23173068 DOI: 10.1021/cn3001069] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 08/29/2012] [Indexed: 12/21/2022] Open
Abstract
For the last two decades, most efforts on new drug development to treat Alzheimer's disease have been focused to inhibit the synthesis of amyloid beta (Aβ), to prevent Aβ deposition, or to clear up Aβ plaques from the brain of Alzheimer's disease (AD) patients. Other pathogenic mechanisms such as the hyperphosphorylation of the microtubular tau protein (that forms neurofibrillary tangles) have also been addressed as, for instance, with inhibitors of the enzyme glycogen synthase-3 kinase beta (GSK3β). However, in spite of their proven efficacy in animal models of AD, all these compounds have so far failed in clinical trials done in AD patients. It seems therefore desirable to explore new concepts and strategies in the field of drug development for AD. We analyze here our hypothesis that a trifunctional chemical entity acting on the L subtype of voltage-dependent Ca(2+) channels (VDCCs) and on the mitochondrial Na(+)/Ca(2+) exchanger (MNCX), and having additional antioxidant properties, may efficiently delay or stop the death of vulnerable neurons in the brain of AD patients. In recent years, evidence has accumulated indicating that enhanced neuronal Ca(2+) cycling (NCC) and futile mitochondrial Ca(2+) cycling (MCC) are central stage in activating calpain and calcineurin, as well as the intrinsic mitochondrial pathway for apoptosis, leading to death of vulnerable neurons. An additional contributing factor to neuronal death is the excess free radical production linked to distortion of Ca(2+) homeostasis. We propose that an hybrid compound containing a dihydropyridine moiety (to block L channels and mitigate Ca(2+) entry) and a benzothiazepine moiety (to block the MNCX and slow down the rate of Ca(2+) efflux from the mitochondrial matrix into the cytosol), as well as a polyphenol moiety (to sequester excess free radicals) could break down the pathological enhanced NCC and MCC, thus delaying the initiation of apoptosis and the death of vulnerable neurons. In so doing, such a trifunctional compound could eventually become a neuroprotective medicine capable of delaying disease progression in AD patients.
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Affiliation(s)
| | - Juan-Alberto Arranz-Tagarro
- Departamento de Farmacología,
Facultad de Farmacia, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | | | | | | | - Antonio G. García
- Servicio de Farmacología
Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Madrid, Spain
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Filevich O, Carrone G, Pavlovsky VA, Etchenique R. Fast optical pH manipulation and imaging. Anal Chem 2012; 84:5618-24. [PMID: 22703044 DOI: 10.1021/ac300608q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We describe a complete system for optical pH manipulation and imaging. The system consists of a photoactive Ruthenium complex capable of inducing a change of more than 5 pH units at the nanosecond time scale. A compatible imaging system acquires microscopic pH images at 1200 fps using a nonexpensive commercial digital camera and an LED illumination system. We use the system as a superb tool to investigate flow in Flow Injection Analysis (FIA) models.
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Affiliation(s)
- Oscar Filevich
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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50
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Padín JF, de Diego AM, Fernández-Morales JC, Merino C, Maroto M, Calvo-Gallardo E, Arranz JA, Yáñez M, García AG. Resveratrol augments nitric oxide generation and causes store calcium release in chromaffin cells. Eur J Pharmacol 2012; 685:99-107. [DOI: 10.1016/j.ejphar.2012.03.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 03/16/2012] [Accepted: 03/23/2012] [Indexed: 12/29/2022]
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