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Hobson BD, Kong L, Angelo MF, Lieberman OJ, Mosharov EV, Herzog E, Sulzer D, Sims PA. Subcellular and regional localization of mRNA translation in midbrain dopamine neurons. Cell Rep 2022; 38:110208. [PMID: 35021090 PMCID: PMC8844886 DOI: 10.1016/j.celrep.2021.110208] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/25/2021] [Accepted: 12/13/2021] [Indexed: 12/12/2022] Open
Abstract
Midbrain dopaminergic (mDA) neurons exhibit extensive dendritic and axonal arborizations, but local protein synthesis is not characterized in these neurons. Here, we investigate messenger RNA (mRNA) localization and translation in mDA neuronal axons and dendrites, both of which release dopamine (DA). Using highly sensitive ribosome-bound RNA sequencing and imaging approaches, we find no evidence for mRNA translation in mDA axons. In contrast, mDA neuronal dendrites in the substantia nigra pars reticulata (SNr) contain ribosomes and mRNAs encoding the major components of DA synthesis, release, and reuptake machinery. Surprisingly, we also observe dendritic localization of mRNAs encoding synaptic vesicle-related proteins, including those involved in exocytic fusion. Our results are consistent with a role for local translation in the regulation of DA release from dendrites, but not from axons. Our translatome data define a molecular signature of sparse mDA neurons in the SNr, including the enrichment of Atp2a3/SERCA3, an atypical ER calcium pump. Local translation regulates the subcellular proteome in neurons but has not been characterized in midbrain dopamine neurons, cells with large dendrites and axonal arborizations. Hobson et al. investigate messenger RNA localization and translation in midbrain dopamine neurons in the mouse brain, finding ribosomes and dopaminergic mRNAs in dendrites, but not axons.
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Affiliation(s)
- Benjamin D Hobson
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Linghao Kong
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA
| | - Maria Florencia Angelo
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Ori J Lieberman
- Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Eugene V Mosharov
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Etienne Herzog
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Peter A Sims
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Department of Biochemistry & Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA; Sulzberger Columbia Genome Center, Columbia University Irving Medical Center, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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Papp B, Launay S, Gélébart P, Arbabian A, Enyedi A, Brouland JP, Carosella ED, Adle-Biassette H. Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation. Int J Mol Sci 2020; 21:ijms21093351. [PMID: 32397400 PMCID: PMC7247589 DOI: 10.3390/ijms21093351] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics. SERCA expression levels and isoenzyme composition vary according to cell type, and this constitutes a mechanism whereby ER calcium homeostasis is adapted to the signaling and metabolic needs of the cell, depending on its phenotype, its state of activation and differentiation. As reviewed here, in several normal epithelial cell types including bronchial, mammary, gastric, colonic and choroid plexus epithelium, as well as in mature cells of hematopoietic origin such as pumps are simultaneously expressed, whereas in corresponding tumors and leukemias SERCA3 expression is selectively down-regulated. SERCA3 expression is restored during the pharmacologically induced differentiation of various cancer and leukemia cell types. SERCA3 is a useful marker for the study of cell differentiation, and the loss of SERCA3 expression constitutes a previously unrecognized example of the remodeling of calcium homeostasis in tumors.
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Affiliation(s)
- Bela Papp
- Institut National de la Santé et de la Recherche Médicale, UMR U976, Institut Saint-Louis, 75010 Paris, France
- Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Université de Paris, 75010 Paris, France
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
- Correspondence: or
| | - Sophie Launay
- EA481, UFR Santé, Université de Bourgogne Franche-Comté, 25000 Besançon, France;
| | - Pascal Gélébart
- Department of Clinical Science-Hematology Section, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway;
| | - Atousa Arbabian
- Laboratoire d’Innovation Vaccins, Institut Pasteur de Paris, 75015 Paris, France;
| | - Agnes Enyedi
- Second Department of Pathology, Semmelweis University, 1091 Budapest, Hungary;
| | - Jean-Philippe Brouland
- Institut Universitaire de Pathologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland;
| | - Edgardo D. Carosella
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
| | - Homa Adle-Biassette
- AP-HP, Service d’Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, 75010 Paris, France;
- Université de Paris, NeuroDiderot, Inserm UMR 1141, 75019 Paris, France
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Lopez JJ, Jardin I, Albarrán L, Sanchez-Collado J, Cantonero C, Salido GM, Smani T, Rosado JA. Molecular Basis and Regulation of Store-Operated Calcium Entry. Adv Exp Med Biol 2020; 1131:445-469. [PMID: 31646520 DOI: 10.1007/978-3-030-12457-1_17] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous mechanism for Ca2+ influx in mammalian cells with important physiological implications. Since the discovery of SOCE more than three decades ago, the mechanism that communicates the information about the amount of Ca2+ accumulated in the intracellular Ca2+ stores to the plasma membrane channels and the nature of these channels have been matters of intense investigation and debate. The stromal interaction molecule-1 (STIM1) has been identified as the Ca2+ sensor of the intracellular Ca2+ compartments that activates the store-operated channels. STIM1 regulates two types of store-dependent channels: the Ca2+ release-activated Ca2+ (CRAC) channels, formed by Orai1 subunits, that conduct the highly Ca2+ selective current I CRAC and the cation permeable store-operated Ca2+ (SOC) channels, which consist of Orai1 and TRPC1 proteins and conduct the non-selective current I SOC. While the crystal structure of Drosophila CRAC channel has already been solved, the architecture of the SOC channels still remains unclear. The dynamic interaction of STIM1 with the store-operated channels is modulated by a number of proteins that either support the formation of the functional STIM1-channel complex or protect the cell against Ca2+ overload.
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Affiliation(s)
- Jose J Lopez
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Isaac Jardin
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain.
| | - Letizia Albarrán
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Jose Sanchez-Collado
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Carlos Cantonero
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Gines M Salido
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics and Group of Cardiovascular Pathophysiology, Institute of Biomedicine of Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/University of Sevilla, Sevilla, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
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Yadav VK, Singh PK, Sharma D, Singh SK, Agarwal V. Mechanism underlying N-(3-oxo-dodecanoyl)-L-homoserine lactone mediated intracellular calcium mobilization in human platelets. Blood Cells Mol Dis 2019; 79:102340. [PMID: 31207554 DOI: 10.1016/j.bcmd.2019.102340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/19/2019] [Accepted: 05/19/2019] [Indexed: 10/26/2022]
Abstract
Acyl-homoserine lactones (AHLs), are the key autoinducer molecules that mediate Pseudomonas aeruginosa associated quorum sensing. P. aeruginosa produces two types of AHLs; N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 HSL) and N-butyryl-L-homoserine lactone (C4 HSL). AHLs are not only regulating the virulence gene of bacteria but also influence the host cell functions by interkingdom signaling. In this study, we explored the mechanism of AHLs induced calcium mobilization in human platelets. We found that 3-oxo-C12 HSL but not C4 HSL induces intracellular calcium release. 3-oxo-C12 HSL induced calcium mobilization was majorly contributed from the dense tubular system (DTS). Furthermore, 3-oxo-C12 HSL also stimulates the store-operated Ca2+ entry (SOCE) in platelet. Intracellular calcium rise was significantly lowered in rotenone, and bafilomycin pre-treated platelets suggesting partial involvement of mitochondria and acidic vacuoles. The significant effect of 3-oxo-C12 HSL on calcium mobilization can alter the platelet functions that might results in thrombotic disorders in individuals infected with P. aeruginosa.
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Affiliation(s)
- Vivek Kumar Yadav
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
| | - Pradeep Kumar Singh
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
| | - Deepmala Sharma
- Department of Mathematics, National Institute of Technology, Raipur, India
| | - Sunil Kumar Singh
- Department of Animal Sciences, Central University of Punjab, Bathinda, India.
| | - Vishnu Agarwal
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India.
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Mammadova-Bach E, Nagy M, Heemskerk JWM, Nieswandt B, Braun A. Store-operated calcium entry in thrombosis and thrombo-inflammation. Cell Calcium 2019; 77:39-48. [PMID: 30530092 DOI: 10.1016/j.ceca.2018.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/31/2018] [Accepted: 11/14/2018] [Indexed: 01/03/2023]
Abstract
Cytosolic free calcium (Ca2+) is a second messenger regulating a wide variety of functions in blood cells, including adhesion, activation, proliferation and migration. Store-operated Ca2+ entry (SOCE), triggered by depletion of Ca2+ from the endoplasmic reticulum, provides a main mechanism of regulated Ca2+ influx in blood cells. SOCE is mediated and regulated by isoforms of the ion channel proteins ORAI and TRP, and the transmembrane Ca2+ sensors stromal interaction molecules (STIMs), respectively. This report provides an overview of the (patho)physiological importance of SOCE in blood cells implicated in thrombosis and thrombo-inflammation, i.e. platelets and immune cells. We also discuss the physiological consequences of dysregulated SOCE in platelets and immune cells and the potential of SOCE inhibition as a therapeutic option to prevent or treat arterial thrombosis as well as thrombo-inflammatory disease states such as ischemic stroke.
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Redondo PC, Berna-Erro A, Dionisio N, Rosado JA. Fluorescence-Based Measurements of the CRAC Channel Activity in Cell Populations. Methods Mol Biol 2018; 1843:69-82. [PMID: 30203278 DOI: 10.1007/978-1-4939-8704-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Cytosolic Ca2+ plays an important role in cellular biology, and since its identification as a second messenger, a number of techniques and methods to analyze the changes in cytosolic Ca2+ concentration ([Ca2+]c) induced by physiological agonists have been developed. Changes in [Ca2+]c might be determined in single cells or in cell populations. Measurement in single cells allows to determine changes in [Ca2+]c at a subcellular level but often results in heterogeneous responses among cells. Determination of intracellular Ca2+ mobilization at the cell population level reduces this heterogeneity and allows [Ca2+]c measurements in small cells that load little amounts of indicator. Here, we describe the measurement of agonist-evoked changes in [Ca2+]c associated with Ca2+ influx in cell populations.
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Abstract
Among the Ca2+ entry mechanisms in platelets, store-operated Ca2+ entry (SOCE) plays a prominent role as it is necessary to achieve full activation of platelet functions and replenish intracellular Ca2+ stores. In platelets, as in other non-excitable cells, SOCE has been reported to involve the activation of plasma membrane channels by the ER Ca2+ sensor STIM1. Despite electrophysiological studies are not possible in human platelets, indirect analyses have revealed that the Ca2+-permeable channels involve Orai1 and, most likely, TRPC1 subunits. A relevant role for the latter has not been found in mouse platelets. There is a body of evidence revealing a number of abnormalities in SOCE or in its molecular regulators that result in qualitative platelet disorders and, as a consequence, altered platelet responsiveness upon stimulation with multiple physiological agonists. Platelet SOCE abnormalities include STIM1 and Orai1 mutations. This chapter summarizes the current knowledge in this field, as well as the disorders associated to platelet SOCE dysfunction.
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Affiliation(s)
- Jose J Lopez
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Gines M Salido
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain.
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Abstract
Endo-lysosomes are acidic organelles that besides the role in macromolecules degradation, act as intracellular Ca(2+) stores. Nicotinic acid adenine dinucleotide phosphate (NAADP), the most potent Ca(2+)-mobilizing second messenger, produced in response to agonist stimulation, activates Ca(2+)-releasing channels on endo-lysosomes and modulates a variety of cellular functions. NAADP-evoked signals are amplified by Ca(2+) release from endoplasmic reticulum, via the recruitment of inositol 1,4,5-trisphosphate and/or ryanodine receptors through a Ca(2+)-induced Ca(2+)- release (CICR) mechanism. The endo-lysosomal Ca(2+) channels activated by NAADP were recently identified as the two-pore channels (TPCs). In addition to TPCs, endo-lysosomes express another distinct family of Ca(2+)- permeable channels, namely the transient receptor potential mucolipin (TRPML) channels, functionally distinct from TPCs. TPCs belong to the voltage-gated channels, resembling voltage-gated Na(+) and Ca(2+) channels. TPCs have important roles in vesicular fusion and trafficking, in triggering a global Ca(2+) signal and in modulation of the membrane excitability. Depletion of acidic Ca(2+) stores has been shown to activate store-operated Ca(2+) entry in human platelets and mouse pancreatic β-cells. In human platelets, Ca(2+) influx in response to acidic stores depletion is facilitated by the tubulin-cytoskeleton and occurs through non-selective cation channels and transient receptor potential canonical (TRPC) channels. Emerging evidence indicates that activation of intracellular receptors, situated on endo-lysosomes, elicits canonical and non-canonical signaling mechanisms that involve CICR and activation of non-selective cation channels in plasma membrane. The ability of endo-lysosomal Ca(2+) stores to modulate the Ca(2+) release from other organelles and the Ca(2+) entry increases the diversity and complexity of cellular signaling mechanisms.
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Affiliation(s)
- G Cristina Brailoiu
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, 901 Walnut St, Rm 916, Philadelphia, PA, 19107, USA.
| | - Eugen Brailoiu
- Center for Substance Abuse Research, Temple University School of Medicine, 3500 N. Broad Street, Room 848, Philadelphia, PA, 19140, USA
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Abstract
Agonist-induced changes in cytosolic Ca(2+) concentration ([Ca(2+)]c) are central events in platelet physiology. A major mechanism supporting agonist-induced Ca(2+) signals is store-operated Ca(2+) entry (SOCE), where the Ca(2+) sensor STIM1 and the channels of the Orai family, as well as TRPC members are the key elements. STIM1-dependent SOCE plays a major role in collagen-stimulated Ca(2+) signaling, phosphatidylserine exposure and thrombin generation. Furthermore, studies involving Orai1 gain-of-function mutants and platelets from Orai1-deficient mice have revealed the importance of this channel in thrombosis and hemostasis to those found in STIM1-deficient mice indicating that SOCE might play a prominent role in thrombus formation. Moreover, increase in TRPC6 expression might lead to thrombosis in humans. The role of STIM1, Orai1 and TRPCs, and thus SOCE, in thrombus formation, suggests that therapies directed against SOCE and targeting these molecules during cardiovascular and cerebrovascular events could significantly improve traditional anti-thrombotic treatments.
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Affiliation(s)
- Alejandro Berna-Erro
- Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, 08003, Spain
| | - Isaac Jardín
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, Cáceres, 10003, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain
| | - Juan A Rosado
- Departamento de Fisiología, University of Extremadura, Cáceres, Spain.
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Abstract
Reviewed are new concepts and models of Ca(2+) signalling originating from work with various animal cells, as well as the applicability of these models to the signalling systems used by blood platelets. The following processes and mechanisms are discussed: Ca(2+) oscillations and waves; Ca(2+) -induced Ca(2+) release; involvement of InsP(3)-receptors and quanta1 release of Ca(2+); different pathways of phospholipase C activation; heterogeneity in the intracellular Ca(2+) stores; store-and receptor-regulated Ca(2+) entry. Additionally, some typical aspects of Ca(2+) signalling in platelets are reviewed: involvement of protein serine/threonine and tyrosine kinases in the regulation of signal transduction; possible functions of platelet glycoproteins; and the importance of Ca(2+) for the exocytotic and procoagulant responses.
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Affiliation(s)
- J W Heemskerk
- Departments of Human Biology/ Biochemistry, University of Limburg, P.O. 616, 6200, MD, Maastricht, The Netherlands
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Paez Espinosa EV, Murad JP, Ting HJ, Khasawneh FT. Mouse transient receptor potential channel 6: Role in hemostasis and thrombogenesis. Biochem Biophys Res Commun 2012; 417:853-6. [DOI: 10.1016/j.bbrc.2011.12.058] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Accepted: 12/14/2011] [Indexed: 11/19/2022]
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Dionisio N, Albarrán L, López JJ, Berna-Erro A, Salido GM, Bobe R, Rosado JA. Acidic NAADP-releasable Ca(2+) compartments in the megakaryoblastic cell line MEG01. Biochim Biophys Acta 2011; 1813:1483-94. [PMID: 21601596 DOI: 10.1016/j.bbamcr.2011.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 04/17/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND A novel family of intracellular Ca(2+)-release channels termed two-pore channels (TPCs) has been presented as the receptors of NAADP (nicotinic acid adenine dinucleotide phosphate), the most potent Ca(2+) mobilizing intracellular messenger. TPCs have been shown to be exclusively localized to the endolysosomal system mediating NAADP-evoked Ca(2+) release from the acidic compartments. OBJECTIVES The present study is aimed to investigate NAADP-mediated Ca(2+) release from intracellular stores in the megakaryoblastic cell line MEG01. METHODS Changes in cytosolic and intraluminal free Ca(2+) concentrations were registered by fluorimetry using fura-2 and fura-ff, respectively; TPC expression was detected by PCR. RESULTS Treatment of MEG01 cells with the H(+)/K(+) ionophore nigericin or the V-type H(+)-ATPase selective inhibitor bafilomycin A1 revealed the presence of acidic Ca(2+) stores in these cells, sensitive to the SERCA inhibitor 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ). NAADP releases Ca(2+) from acidic lysosomal-like Ca(2+) stores in MEG01 cells probably mediated by the activation of TPC1 and TPC2 as demonstrated by TPC1 and TPC2 expression silencing and overexpression. Ca(2+) efflux from the acidic lysosomal-like Ca(2+) stores or the endoplasmic reticulum (ER) results in ryanodine-sensitive activation of Ca(2+)-induced Ca(2+) release (CICR) from the complementary Ca(2+) compartment. CONCLUSION Our results show for the first time NAADP-evoked Ca(2+) release from acidic compartments through the activation of TPC1 and TPC2, and CICR, in a megakaryoblastic cell line.
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Affiliation(s)
- Natalia Dionisio
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain
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Zbidi H, Jardin I, Bartegi A, Salido GM, Rosado JA. Ca2+ leakage rate from agonist-sensitive intracellular pools is altered in platelets from patients with type 2 diabetes. Platelets 2011; 22:284-93. [PMID: 21526890 DOI: 10.3109/09537104.2010.528813] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Platelets from patients with type 2 diabetes show abnormalities in intracellular Ca(2+) homeostasis that are involved in platelet hyperaggregability and the development of thrombotic complications. Different Ca(2+) transport mechanisms have been reported to be altered in platelets from patients with type 2 diabetes, including the sarcoendoplasmic and plasma membrane Ca(2+)-ATPases, plasma membrane Ca(2+) channels, or the Na(+)/Ca(2+) exchanger. Here, we have investigated whether passive Ca(2+) leak from the stores is altered in platelets from patients with type 2 diabetes. Resting cytosolic Ca(2+) concentration ([Ca(2+)](i)) was found to be greater in platelets from patients with type 2 diabetes than in healthy controls. In a Ca(2+)-free medium, platelet stimulation with thrombin or ADP evokes a rapid and transient increase in [Ca(2+)](i) that was found to be greater in patients with diabetes than in healthy controls. Sequential or combined inhibition of Ca(2+) extrusion and Ca(2+) sequestration into the stores reduced the difference between the responses to agonists in patients with diabetes and healthy controls, although agonist-induced Ca(2+) efflux from the stores was still significantly greater in patients with diabetes. Ca(2+) leak from the dense tubular system or the acidic stores, induced by a low concentration of thapsigargin or 2,5-di-(t-butyl)-1,4-hydroquinone (TBHQ), respectively, was clearly greater in patients with diabetes than in controls, and was not significantly modified by treatment with 2-APB. These findings indicate that passive Ca(2+) leakage rate from the intracellular stores in platelets is significantly enhanced in patients with type 2 diabetes mellitus and this might explain the increased resting [Ca(2+)](i).
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Affiliation(s)
- Hanene Zbidi
- Unité de Recherche de Biochimie, Institute Supérieur de Biotechnologie, 5019-Monastir, Tunisia
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Zbidi H, Jardin I, Woodard GE, Lopez JJ, Berna-Erro A, Salido GM, Rosado JA. STIM1 and STIM2 are located in the acidic Ca2+ stores and associates with Orai1 upon depletion of the acidic stores in human platelets. J Biol Chem 2011; 286:12257-70. [PMID: 21321120 PMCID: PMC3069429 DOI: 10.1074/jbc.m110.190694] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 02/11/2011] [Indexed: 11/06/2022] Open
Abstract
Mammalian cells accumulate Ca2+ into agonist-sensitive acidic organelles, vesicles that possess a vacuolar proton-ATPase. Acidic Ca2+ stores include secretory granules and lysosome-related organelles. Current evidence clearly indicates that acidic Ca2+ stores participate in cell signaling and function, including the activation of store-operated Ca2+ entry in human platelets upon depletion of the acidic stores, although the mechanism underlying the activation of store-operated Ca2+ entry controlled by the acidic stores remains unclear. STIM1 has been presented as the endoplasmic reticulum Ca2+ sensor, but its role sensing intraluminal Ca2+ concentration in the acidic stores has not been investigated. Here we report that STIM1 and STIM2 are expressed in the lysosome-related organelles and dense granules in human platelets isolated by immunomagnetic sorting. Depletion of the acidic Ca2+ stores using the specific vacuolar proton-ATPase inhibitor, bafilomycin A1, enhanced the association between STIM1 and STIM2 as well as between these proteins and the plasma membrane channel Orai1. Depletion of the acidic Ca2+ stores also induces time-dependent co-immunoprecipitation of STIM1 with the TRPC proteins hTRPC1 and hTRPC6, as well as between Orai1 and both TRPC proteins. In addition, bafilomycin A1 enhanced the association between STIM2 and SERCA3. These findings demonstrate the location of STIM1 and STIM2 in the acidic Ca2+ stores and their association with Ca2+ channels and ATPases upon acidic stores discharge.
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Affiliation(s)
- Hanene Zbidi
- From the Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain
| | - Isaac Jardin
- From the Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain
| | | | - Jose J. Lopez
- Hémostase et Dynamique Cellulaire Vasculaire U770, INSERM, 94276 Le Kremlin-Bicêtre, France
| | - Alejandro Berna-Erro
- From the Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain
| | - Ginés M. Salido
- From the Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain
| | - Juan A. Rosado
- From the Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain
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Clark JH, Kinnear NP, Kalujnaia S, Cramb G, Fleischer S, Jeyakumar LH, Wuytack F, Evans AM. Identification of functionally segregated sarcoplasmic reticulum calcium stores in pulmonary arterial smooth muscle. J Biol Chem 2010; 285:13542-9. [PMID: 20177054 PMCID: PMC2859515 DOI: 10.1074/jbc.m110.101485] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In pulmonary arterial smooth muscle, Ca(2+) release from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) may induce constriction and dilation in a manner that is not mutually exclusive. We show here that the targeting of different sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases (SERCA) and RyR subtypes to discrete SR regions explains this paradox. Western blots identified protein bands for SERCA2a and SERCA2b, whereas immunofluorescence labeling of isolated pulmonary arterial smooth muscle cells revealed striking differences in the spatial distribution of SERCA2a and SERCA2b and RyR1, RyR2, and RyR3, respectively. Almost all SERCA2a and RyR3 labeling was restricted to a region within 1.5 microm of the nucleus. In marked contrast, SERCA2b labeling was primarily found within 1.5 microm of the plasma membrane, where labeling for RyR1 was maximal. The majority of labeling for RyR2 lay in between these two regions of the cell. Application of the vasoconstrictor endothelin-1 induced global Ca(2+) waves in pulmonary arterial smooth muscle cells, which were markedly attenuated upon depletion of SR Ca(2+) stores by preincubation of cells with the SERCA inhibitor thapsigargin but remained unaffected after preincubation of cells with a second SERCA antagonist, cyclopiazonic acid. We conclude that functionally segregated SR Ca(2+) stores exist within pulmonary arterial smooth muscle cells. One sits proximal to the plasma membrane, receives Ca(2+) via SERCA2b, and likely releases Ca(2+) via RyR1 to mediate vasodilation. The other is located centrally, receives Ca(2+) via SERCA2a, and likely releases Ca(2+) via RyR3 and RyR2 to initiate vasoconstriction.
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Affiliation(s)
- Jill H Clark
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
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18
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Jardín I, López JJ, Redondo PC, Salido GM, Rosado JA. Store-operated Ca2+ entry is sensitive to the extracellular Ca2+ concentration through plasma membrane STIM1. Biochim Biophys Acta 2009; 1793:1614-22. [PMID: 19631699 DOI: 10.1016/j.bbamcr.2009.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 07/03/2009] [Accepted: 07/13/2009] [Indexed: 01/06/2023]
Abstract
Store-operated Ca(2+) entry (SOCE) is a major mechanism for Ca(2+) influx in platelets and other cells activated by a reduction in Ca(2+) concentration in the intracellular stores. SOCE has been reported to be regulated by extracellular Ca(2+), although the underlying mechanism remains unclear. Here we have examined the involvement of plasma membrane-located STIM1 (PM-STIM1) in the regulation of SOCE by extracellular Ca(2+). Treatment of platelets with the SERCA inhibitor thapsigargin (TG) induced Mn(2+) entry, which was inhibited by extracellular Ca(2+) in a concentration-dependent manner. Incubation of platelets with a specific antibody, which recognizes the extracellular amino acid sequence 25-139 of PM-STIM1 that contains the Ca(2+)-binding domain, prevented the inactivation of Ca(2+) entry induced by extracellular Ca(2+). TG induced translocation of STIM1 to the plasma membrane (PM), an event that was found to be Ca(2+)-dependent. In addition, TG stimulated association of PM-STIM1 with Orai1, an event that was not prevented by stabilization of the membrane cytoskeleton using jasplakinolide. These findings suggest that PM-STIM1 is important for the inactivation of SOCE by extracellular Ca(2+), an event that is likely to be mediated by interaction with Orai1.
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Affiliation(s)
- Isaac Jardín
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10071 Cáceres, Spain
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19
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Bredoux R, Corvazier E, Dally S, Chaabane C, Bobe R, Raies A, Moreau A, Enouf J. Human platelet Ca2+-ATPases: New markers of cell differentiation as illustrated in idiopathic scoliosis. Platelets 2009; 17:421-33. [PMID: 16973504 DOI: 10.1080/09537100600758719] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The aetiology of adolescent idiopathic scoliosis (AIS), the most common form of scoliosis, is unclear. Previous studies showed controversial platelet abnormalities including intracellular calcium. Platelet Ca2+ homeostasis is controlled by a multi-Ca2+-ATPase system including SERCA (sarco/endoplasmic reticulum Ca2+-ATPase) and PMCA (plasma membrane Ca2+-ATPase) isoforms. Here, we first investigated the expression of PMCA4b, SERCA3a and SERCA2b isoforms in platelets of 17 patients with AIS. Patients presenting thoracic curves were found to present a higher PMCA4b expression coupled to a lower SERCA3a one in agreement with an abnormality in platelet maturation. Indeed, using PMA-treated MEG 01 cells, an in vitro model of megakaryocytopoiesis, we found an increase in SERCA3a expression, associated to a caspase-3 mediated C terminal proteolysis of PMCA4b. To look whether platelets reflect a basic defect in cell differentiation, we next identified osteoblast Ca2+-ATPases and studied their expressions in AIS. Major expressions of PMCA4b and SERCA2b were found in normal osteoblasts. Comparing platelets and osteoblasts in two additional patients with AIS, we found opposite and concerted regulations of the expressions of PMCA4b and caspase-3 substrate, PARP in both cell types. A systemic defect in cell differentiation involving caspase-3 can be proposed as a novel mechanism in the etiopathogenesis of the most frequent type of AIS. *R. Bredoux and E. Corvazier contributed equally to this work.
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20
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Bobe R, Bredoux R, Corvazier E, Lacabaratz-Porret C, Martin V, Kovács T, Enouf J. How many Ca2+ATPase isoforms are expressed in a cell type? A growing family of membrane proteins illustrated by studies in platelets. Platelets 2009; 16:133-50. [PMID: 16011958 DOI: 10.1080/09537100400016847] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ca(2+) signaling plays a key role in normal and abnormal platelet functions. Understanding platelet Ca(2+) signaling requires the knowledge of proteins involved in this process. Among these proteins are Ca(2+)ATPases or Ca(2+) pumps that deplete the cytosol of Ca(2+) ions. Here, we will particularly focus on two Ca(2+) pump families: the plasma membrane Ca(2+)ATPases (PMCAs) that extrude cytosolic Ca(2+) towards the extracellular medium and the sarco/endoplasmic reticulum Ca(2+)ATPases (SERCAs) that pump Ca(2+) into the endoplasmic reticulum (ER). In the present review, we will summarize data on platelet Ca(2+)ATPases including their identification and biogenesis. First of all, we will present the Ca(2+)ATPase genes and their isoforms expressed in platelets. We will especially focus on a member of the SERCA family, SERCA3, recently found to give rise to a number of species-specific isoforms. Next, we will describe the differences in Ca(2+)ATPase patterns observed in human and rat platelets. Last, we will analyze how the expression of Ca(2+)ATPase isoforms changes during megakaryocytic maturation and show that megakaryocytopoiesis is associated with a profound reorganization of the expression and/or activity of Ca(2+)ATPases. Taken together, these data provide new aspects of investigations to better understand normal and abnormal platelet Ca(2+) signaling.
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Affiliation(s)
- R Bobe
- INSERM U.689 E6, IFR139 Lariboisière, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
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21
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Dally S, Chaabane C, Dally S, Chaabane C, Corvazier E, Bredoux R, Bobe R, Ftouhi B, Slimane H, Raies A, Enouf J. Increased expression of plasma membrane Ca2+ATPase 4b in platelets from hypertensives: A new sign of abnormal thrombopoiesis? Platelets 2009; 18:543-9. [DOI: 10.1080/09537100701501646] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Abstract
Agonist-induced elevation in cytosolic Ca2+ concentrations is essential for platelet activation in hemostasis and thrombosis. It occurs through Ca2+ release from intracellular stores and Ca2+ entry through the plasma membrane (PM). Ca2+ store release is a well-established process involving phospholipase (PL)C-mediated production of inositol-1,4,5-trisphosphate (IP3), which in turn releases Ca2+ from the intracellular stores through IP3 receptor channels. In contrast, the mechanisms controlling Ca2+ entry and the significance of this process for platelet activation have been elucidated only very recently. In platelets, as in other non-excitable cells, the major way of Ca2+ entry involves the agonist-induced release of cytosolic sequestered Ca2+ followed by Ca2+ influx through the PM, a process referred to as store-operated calcium entry (SOCE). It is now clear that stromal interaction molecule 1 (STIM1), a Ca2+ sensor molecule in intracellular stores, and the four transmembrane channel protein Orai1 are the key players in platelet SOCE. The other major Ca2+ entry mechanism is mediated by the direct receptor-operated calcium (ROC) channel, P2X1. Besides these, canonical transient receptor potential channel (TRPC) 6 mediates Ca2+ entry through the PM. This review summarizes the current knowledge of platelet Ca2+ homeostasis with a focus on the newly identified Ca2+ entry mechanisms.
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Affiliation(s)
- D Varga-Szabo
- Chair of Vascular Medicine and Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
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23
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López JJ, Redondo PC, Salido GM, Pariente JA, Rosado JA. N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine induces apoptosis through the activation of caspases-3 and -8 in human platelets. A role for endoplasmic reticulum stress. J Thromb Haemost 2009; 7:992-9. [PMID: 19548908 DOI: 10.1111/j.1538-7836.2009.03431.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Apoptosis or programmed cell death involves a number of biochemical events, including the activation of caspases, which lead to specific cell morphology changes and ultimately cell death. Traditionally, two apoptotic pathways have been described: the cell-surface death receptor-dependent extrinsic pathway and the mitochondria-dependent intrinsic pathway. Alternatively, apoptosis has been reported to be induced by endoplasmic reticulum (ER) stress, which is mainly induced by a reduction in intraluminal free Ca(2+) concentration ([Ca(2+)](ER)). OBJECTIVES The present study aimed to investigate the development of apoptotic events after ER stress induced by N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), an ER Ca(2+) chelator, in human platelets. METHODS Changes in cytosolic free Ca(2+) concentration, caspase activity and phosphatidylserine externalization were determined by fluorimetric techniques. RESULTS Our results indicate that TPEN reduces the amount of free Ca(2+) releasable by the Ca(2+)-mobilizing agonist thrombin. TPEN induced activation of caspase-3, -8 and -9 and subsequent phosphatidylserine externalization. The ability of TPEN to induce phosphatidylserine externalization was smaller than that of thrombin. In addition, TPEN was able to induce phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2 alpha). TPEN-mediated caspase-3 activation requires functional caspase-8, but is independent of H(2)O(2) generation. Activation of caspase-3 and -8 by TPEN was prevented by salubrinal, an agent that prevents ER stress-induced apoptosis. CONCLUSION These findings provide experimental evidence for the existence of ER stress-mediated apoptosis in human platelets, a process that might limit platelet life span upon prolonged stimulation with agonists.
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Affiliation(s)
- J J López
- Department of Physiology, University of Extremadura, Cáceres, Spain
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24
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Alexandru N, Jardín I, Popov D, Simionescu M, García-Estañ J, Salido GM, Rosado JA. Effect of homocysteine on calcium mobilization and platelet function in type 2 diabetes mellitus. J Cell Mol Med 2009; 12:2586-97. [PMID: 18088391 PMCID: PMC3828875 DOI: 10.1111/j.1582-4934.2008.00195.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Type 2 diabetes mellitus induces a characteristic platelet hyperactivity that might be due to several factors including oxidative stress and abnormal intracellular Ca2+ homeostasis. Hyperhomocysteinaemia is considered a risk factor in the development of thrombosis although its effect on platelet function and the mechanisms involved are still poorly understood. Here we show that homocysteine (Hcy) induce a concentration-dependent increase in endogenous production of reactive oxygen species (ROS), which was significantly greater in platelets from diabetic patients than in controls. Platelet treatment with Hcy resulted in Ca2+ release from the dense tubular system and the acidic stores. Ca2+ mobilisation-induced by Hcy consisted in two components, an initial slow increase in intracellular free Ca2+ concentration ([Ca2+]i) and a rapid and marked increase in [Ca2+]i, the second leading to the activation of platelet aggregation. As well as ROS generation, Ca2+ mobilization and platelet aggregation were significantly greater in platelets from diabetic donors than in controls, which indicate that platelets from diabetic donors are more sensitive to Hcy. These findings, together with the hyperhomocysteinaemia reported in diabetic patients, strongly suggest that Hcy might be considered a risk factor in the development of cardiovascular complications associated to type 2 diabetes mellitus.
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Affiliation(s)
- N Alexandru
- Institute of Cellular Biology and Pathology N. Simionescu, Bucharest, Romania
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25
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Alexandru N, Jardín I, Popov D, Simionescu M, García-Estañ J, Salido GM, Rosado JA. Effect of homocysteine on calcium mobilization and platelet function in type 2 diabetes mellitus. J Cell Mol Med 2009; 12:2015-26. [PMID: 19012728 PMCID: PMC4506167 DOI: 10.1111/j.1582-4934.2008.00200.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Type 2 diabetes mellitus induces a characteristic platelet hyperactivity that might be due to several factors including oxidativ stress and abnormal intracellular Ca2+ homeostasis. Hyperhomocysteinaemia is considered a risk factor in the development of thrombosis although its effect on platelet function and the mechanisms involved are still poorly understood. Here we show tha homocysteine induce a concentration-dependent increase in endogenous production of reactive oxygen species (ROS), which was significantly greater in platelets from diabetic patients than in controls. Platelet treatment with homocysteine resulted in Ca2+ release from the dense tubular system and the acidic stores. Ca2+ mobilization-induced by homocysteine consisted in two components, an initial slow increase in intracellular free Ca + concentration ([Ca +]i) and a rapid and marked increase in [Ca2+]i, th second leading to the activation of platelet aggregation. As well as ROS generation, Ca2+ mobilization and platelet aggregation were significantly greater in platelets from diabetic donors than in controls, which indicate that platelets from diabetic donors are more sensitive to homocysteine. These findings, together with the hyperhomocysteinaemia reported in diabetic patients, strongly suggest that homocysteine might be considered a risk factor in the development of cardiovascular complications associated to type 2 diabetes mellitus.
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Affiliation(s)
- N Alexandru
- Institute of Cellular Biology and Pathology N. Simionescu, Bucharest, Romania
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26
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López JJ, Jardín I, Bobe R, Pariente JA, Enouf J, Salido GM, Rosado JA. STIM1 regulates acidic Ca2+ store refilling by interaction with SERCA3 in human platelets. Biochem Pharmacol 2008; 75:2157-64. [PMID: 18439569 DOI: 10.1016/j.bcp.2008.03.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 03/06/2008] [Accepted: 03/14/2008] [Indexed: 11/28/2022]
Abstract
Ca(2+) mobilization regulates a wide variety of cellular functions. Platelets possess agonist-releasable Ca(2+) stores in acidic organelles where sarcoendoplasmic reticulum Ca(2+)-ATPase-3 (SERCA) pump is involved in store refilling. Stromal interaction molecule 1 (STIM1), which has been presented as a central regulator of platelet function, is a Ca(2+) sensor of the intracellular Ca(2+) stores. Here we present that STIM1 is required for acidic store refilling. Electrotransjection of cells with anti-STIM1 (Y(231)-K(243)) antibody, directed towards a cytoplasmic sequence of STIM1, significantly reduced acidic store refilling, which was tested by remobilizing Ca(2+) from the acidic stores using 2,5-di-(t-butyl)-1,4-hydroquinone (TBHQ) after a brief refilling period that followed thrombin stimulation. Platelet treatment with thrombin or thapsigargin in combination with ionomycin, to induce extensive Ca(2+) store depletion, resulted in a transient increase in the interaction between STIM1 and SERCA3, reaching a maximum 30 s after stimulation. The coupling between STIM1 and SERCA3 was abolished by electrotransjection with anti-STIM1 antibody. The interaction between STIM1 and SERCA3 induced by thrombin or by treatment with thapsigargin plus ionomycin is reduced in platelets from type 2 diabetic patients, as well as Ca(2+) reuptake into the acidic Ca(2+) stores. These findings provide evidence for a role of STIM1 in acidic store refilling in platelets probably acting as a Ca(2+) sensor and regulating the activity of SERCA3. This action is impaired in platelets from type 2 diabetics, which might lead to the enhanced cytosolic Ca(2+) concentration observed and, therefore, in platelet hyperactivity.
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Affiliation(s)
- Jose J López
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, Caceres 10071, Spain
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27
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Korošec B, Glavač D, Volavšek M, Ravnik-glavač M. Alterations in genes encoding sarcoplasmic-endoplasmic reticulum Ca2+ pumps in association with head and neck squamous cell carcinoma. ACTA ACUST UNITED AC 2008; 181:112-8. [DOI: 10.1016/j.cancergencyto.2007.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 12/06/2007] [Indexed: 11/21/2022]
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28
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Jardín I, López JJ, Pariente JA, Salido GM, Rosado JA. Intracellular Calcium Release from Human Platelets: Different Messengers for Multiple Stores. Trends Cardiovasc Med 2008; 18:57-61. [DOI: 10.1016/j.tcm.2007.12.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 11/22/2007] [Accepted: 12/06/2007] [Indexed: 11/24/2022]
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29
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Redondo PC, Salido GM, Pariente JA, Sage SO, Rosado JA. SERCA2b and 3 play a regulatory role in store-operated calcium entry in human platelets. Cell Signal 2008; 20:337-46. [DOI: 10.1016/j.cellsig.2007.10.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 10/18/2007] [Indexed: 11/26/2022]
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30
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Redondo PC, Jardin I, Lopez JJ, Salido GM, Rosado JA. Intracellular Ca2+ store depletion induces the formation of macromolecular complexes involving hTRPC1, hTRPC6, the type II IP3 receptor and SERCA3 in human platelets. Biochim Biophys Acta 2007; 1783:1163-76. [PMID: 18191041 DOI: 10.1016/j.bbamcr.2007.12.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 12/11/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
Abstract
Endogenously expressed human canonical transient receptor potential 1 (hTRPC1) and human canonical transient receptor potential 6 (hTRPC6) have been shown to play a role in store-operated Ca2+ entry (SOCE) in human platelets, where two mechanisms for SOCE, regulated by the dense tubular system (DTS) or the acidic granules, have been identified. In cells preincubated for 1 min with 100 microM flufenamic acid we show that hTRPC6 is involved in SOCE activated by both mechanisms, as demonstrated by selective depletion of the DTS or the acidic stores, using thapsigargin (TG) (10 nM) or 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ) (20 microM), respectively, although it is more relevant after acidic store depletion. Co-immunoprecipitation experiments indicated that depletion of both stores separately results in time-dependent interaction between hTRPC1 and hTRPC6, and also between both hTRPCs and the type II IP3 receptor (IP3RII). The latter was greater after treatment with TG. TBHQ-induced coupling between hTRPC1 and 6 was transient and decreased after 30s of treatment, while that induced by TG increased for at least 3 min. TBHQ induced association between SERCA3, located in the acidic stores, hTRPC1, hTRPC6 and Orai1. TBHQ also evoked coupling between SERCA3 and IP3RII, presumably located in the DTS, thus suggesting interplay between both Ca2+ stores. Similarly, TG induces the interaction of SERCA2b with hTRPC1 and 6 and the IP3RII. The interactions between hTRPC1, hTRPC6, IP3RII and SERCA3 were impaired by disruption of the microtubules, supporting a role for microtubules in Ca2+ homeostasis. In conclusion, the present data demonstrate for the first time that hTRPC1, hTRPC6, IP3RII and SERCA3 are parts of a macromolecular protein complex activated by depletion of the intracellular Ca2+ stores in human platelets.
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Affiliation(s)
- Pedro C Redondo
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB2 3EG Cambridge, UK.
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31
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Jardín I, López JJ, Salido GM, Rosado JA. Functional relevance of the de novo coupling between hTRPC1 and type II IP3 receptor in store-operated Ca2+ entry in human platelets. Cell Signal 2007; 20:737-47. [PMID: 18249094 DOI: 10.1016/j.cellsig.2007.12.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 12/13/2007] [Accepted: 12/13/2007] [Indexed: 12/16/2022]
Abstract
Store-operated Ca2+ entry (SOCE), a major mechanism for Ca2+ entry in non-excitable cells, is regulated by the filling state of the intracellular Ca2+ stores. We have previously reported that a de novo conformational coupling between the type II IP3 receptor (IP3RII) and hTRPC1 channel occurs after depletion of the intracellular Ca2+ stores in human platelets, which might be involved in the activation of SOCE in these cells. Here we present for the first time direct evidence for the functional relevance of the coupling between hTRPC1 and IP3RII in SOCE in human platelets. Our data suggest that at least two pathways may contribute to SOCE in these cells. An early component, insensitive to cytochalasin D (Cyt D), is followed by a late component which is sensitive to Cyt D. Introduction of a peptide corresponding to IP3RII(317-334) (IP3BD-peptide(317-334)) in the cells by electrotransjection impairs the coupling between hTRPC1 and IP3RII but not the interaction between hTRPC1 and STIM1 induced by store depletion. Coimmunoprecipitation experiments indicated that endogenously expressed hTRPC1 interacts with the IP3BD-peptide(317-334). Electrotransjection of cells with IP3BD-peptide(317-334), significantly attenuated the late stage of Ca2+ and Mn2+ entry induced by 10 nM thapsigargin (TG) or 20 microM 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ), providing evidence for a functional role of the de novo coupling between hTRPC1 and IP3RII in the activation of SOCE in human platelets.
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Affiliation(s)
- Isaac Jardín
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10071 Cáceres, Spain
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32
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Juška A, Jardin I, Rosado JA. Physical properties of two types of calcium stores and SERCAs in human platelets. Mol Cell Biochem 2008; 311:9-18. [DOI: 10.1007/s11010-007-9687-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 12/05/2007] [Indexed: 10/22/2022]
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33
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Chaabane C, Dally S, Corvazier E, Bredoux R, Bobe R, Ftouhi B, Raies A, Enouf J. Platelet PMCA- and SERCA-type Ca2+ -ATPase expression in diabetes: a novel signature of abnormal megakaryocytopoiesis. J Thromb Haemost 2007; 5:2127-35. [PMID: 17883705 DOI: 10.1111/j.1538-7836.2007.02709.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Previous studies have shown platelet Ca(2+) abnormalities in diabetes mellitus and some reports suggest abnormal platelet production. Platelet Ca(2+) homeostasis is controlled by a multi-Ca(2+)-ATPase system that includes two plasma membrane Ca(2+)-ATPase (PMCA) and seven sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) isoforms. In addition, we recently found that the expression of PMCA4b and SERCA3 isoforms may serve as new markers of abnormal megakaryocytopoiesis [Nurden P et al. Impaired megakaryocytopoiesis in type 2B von Willebrand disease with severe thrombocytopenia. Blood 2006; 108: 2587-95]. AIM To analyze the expression of major platelet Ca(2+)-ATPases in 27 patients with type 1 or type 2 diabetes (T1D or T2D) compared with normal donors. METHODS Investigation of protein and mRNA expressions of PMCA1b and PMCA4b, and SERCA2b, SERCA3a and SERCA3b, using specific Western blotting and reverse transcriptase-polymerase chain reaction, respectively. RESULTS Remarkably, all patients with T1D were found to present a higher expression of PMCA4b protein (212% +/- 28%; n = 10) and PMCA4b mRNA (155% +/- 16%; n = 17), coupled with a higher expression of SERCA3b mRNA (165% +/- 9%) in some cases. Patients with T2D (n = 10) were also studied for protein expression and were found to present similar major upregulation of the expression of PMCA4b protein (180% +/- 28%; n = 10). Lastly, five of 10 patients with T1D were studied for PMCA4b expression after insulin treatment, with four of five recovering normal expression (96% +/- 15%; n = 5). CONCLUSIONS Compared with the expression of PMCA4b upon platelet maturation, platelets from diabetic patients exhibit similarities with immature megakaryocytes. Thus, this study reinforces the idea that abnormal megakaryocytopoiesis can provide additional insights into diabetes and could represent a novel therapeutic target for antithrombotic drugs.
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Affiliation(s)
- C Chaabane
- U689 INSERM, CRCIL, Hôpital Lariboisière, Paris Cedex 10, France
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Jardin I, Ben Amor N, Hernández-Cruz JM, Salido GM, Rosado JA. Involvement of SNARE proteins in thrombin-induced platelet aggregation: Evidence for the relevance of Ca2+ entry. Arch Biochem Biophys 2007; 465:16-25. [PMID: 17543880 DOI: 10.1016/j.abb.2007.04.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 04/27/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
Thrombin induces platelet activation through a variety of intracellular mechanisms, including Ca(2+) mobilization. The protein of the exocytotic machinery SNAP-25, but not VAMPs, is required for store-operated Ca(2+) entry, the main mechanism for Ca(2+) influx in platelets. Hence, we have investigated the role of the SNAP-25 and VAMPs in thrombin-induced platelet aggregation. Platelet stimulation with thrombin or selective activation of thrombin receptors PAR-1, PAR-4 or GPIb-IX-V results in platelet aggregation that, except for GPIb-IX-V receptor, requires Ca(2+) entry for full activation. Depletion of the intracellular Ca(2+) stores using pharmacological tools was unable to induce aggregation except when cytosolic Ca(2+) concentration reached a critical level (around 1.5 microM). Electrotransjection of cells with anti-SNAP-25 antibody reduced thrombin-evoked platelet aggregation, while electrotransjection of anti-VAMP-1, -2 and -3 antibody had no effect. These findings support a role for SNAP-25 but not VAMP-1, -2 and -3 in platelet aggregation, which is likely mediated by the regulation of Ca(2+) mobilization in human platelets.
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Affiliation(s)
- Isaac Jardin
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, Av. Universidad s/n, Cáceres 10071, Spain
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Jardín I, Redondo PC, Salido GM, Rosado JA. Phosphatidylinositol 4,5-bisphosphate enhances store-operated calcium entry through hTRPC6 channel in human platelets. Biochim Biophys Acta 2007; 1783:84-97. [PMID: 17719101 DOI: 10.1016/j.bbamcr.2007.07.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/29/2007] [Accepted: 07/19/2007] [Indexed: 10/23/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) is a versatile regulator of TRP channels. We report that inclusion of a PIP2 analogue, PIP2 1,2-dioctanoyl, does not induce non-capacitative Ca2+ entry per se but enhanced Ca2+ entry stimulated either by thrombin or by selective depletion of the Ca2+ stores in platelets, the dense tubular system, using 10 nM TG, and the acidic stores, using 20 microM 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ). Reduction of PIP2 levels by blocking PIP2 resynthesis with Li+ or introducing a monoclonal anti-PIP2 antibody, or sequestering PIP2 using poly-lysine, attenuated Ca2+ entry induced by thrombin, TG and TBHQ, and reduced thrombin-evoked, but not TG- or TBHQ-induced, Ca2+ release from the stores. Incubation with the anti-hTRPC1 antibody did not alter the stimulation of Ca2+ entry by PIP2, whilst introduction of anti-hTRPC6 antibody directed towards the C-terminus of hTRPC6 reduced Ca2+ and Mn2+ entry induced by thrombin, TG or TBHQ, and abolished the stimulation of Ca2+ entry by PIP2. The anti-hTRPC6 antibody, but not the anti-hTRPC1 antibody or PIP2, reduced non-capacitative Ca2+ entry by the DAG analogue 1-oleoyl-2-acetyl-sn-glycerol. In summary, hTRPC6 plays a role both in store-operated and in non-capacitative Ca2+ entry. PIP2 enhances store-operated Ca2+ entry in human platelets, most probably by stimulation of hTRPC6 channels.
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Affiliation(s)
- Isaac Jardín
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10071 Cáceres, Spain
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36
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Redondo PC, Harper AGS, Sage SO, Rosado JA. Dual role of tubulin-cytoskeleton in store-operated calcium entry in human platelets. Cell Signal 2007; 19:2147-54. [PMID: 17681754 DOI: 10.1016/j.cellsig.2007.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 06/15/2007] [Indexed: 11/30/2022]
Abstract
Two mechanisms for store-operated Ca(2+) entry (SOCE) regulated by two independent Ca(2+) stores, the dense tubular system (DTS) and the acidic stores, have been described in platelets. We have previously suggested that coupling between the type II IP(3) receptor (IP(3)RII) and hTRPC1, involving reorganization of the actin microfilaments, play an important role in SOCE. However, the involvement of the tubulin microtubules, located beneath the plasma membrane, remains unclear. Here we show that the microtubule disrupting agent colchicine reduced Ca(2+) entry stimulated by low concentrations (0.1 U/mL) of thrombin, which activates SOCE mostly by depleting acidic Ca(2+)-store. Consistently, colchicine reduced SOCE activated by 2,5 di-(tertbutyl)-1,4-hydroquinone (TBHQ), which selectively depletes the acidic Ca(2+) stores. In contrast, colchicine enhanced SOCE mediated by depletion of the DTS, induced by high concentrations of thapsigargin (TG), which depletes both the acidic Ca(2+) stores and the DTS, the major releasable Ca(2+) store in platelets. These findings were confirmed by using Sr(2+) as a surrogate for Ca(2+) entry. Colchicine attenuated the coupling between IP(3)RII and hTRPC1 stimulated by thrombin while it enhanced that evoked by TG. Paclitaxel, which induces microtubular stabilization and polymerization, exerted the opposite effects on thrombin- and TG-evoked SOCE and coupling between IP(3)RII and hTRPC1 compared with colchicine. Neither colchicine nor paclitaxel altered the ability of platelets to extrude Ca(2+). These findings suggest that tubulin microtubules play a dual role in SOCE, acting as a barrier that prevents constitutive SOCE regulated by DTS, but also supporting SOCE mediated by the acidic Ca(2+) stores.
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Affiliation(s)
- Pedro C Redondo
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, Downing Site, UK.
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Jardin I, Ben Amor N, Bartegi A, Pariente J, Salido G, Rosado J. Differential involvement of thrombin receptors in Ca2+ release from two different intracellular stores in human platelets. Biochem J 2007; 401:167-74. [PMID: 16939417 PMCID: PMC1698687 DOI: 10.1042/bj20060888] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Physiological agonists increase cytosolic free Ca2+ concentration to regulate a number of cellular processes. The platelet thrombin receptors, PAR (protease-activated receptor) 1 PAR-4 and GPIb-IX-V (glycoprotein Ib-IX-V) have been described as potential contributors of thrombin-induced platelet aggregation. Platelets present two separate Ca2+ stores, the DTS (dense tubular system) and acidic organelles, differentiated by the distinct sensitivity of their respective SERCAs (sarcoplasmic/endoplasmic-reticulum Ca2+-ATPases) to TG (thapsigargin) and TBHQ [2,5-di-(tert-butyl)-1,4-hydroquinone]. However, the involvement of the thrombin receptors in Ca2+ release from each Ca2+ store remains unknown. Depletion of the DTS using ADP, which releases Ca2+ solely from the DTS, in combination with 10 nM TG, to selectively inhibit SERCA2 located on the DTS reduced Ca2+ release evoked by the PAR-1 agonist, SFLLRN, and the PAR-4 agonist, AYPGKF, by 80 and 50% respectively. Desensitization of PAR-1 and PAR-4 or pre-treatment with the PAR-1 and PAR-4 antagonists SCH 79797 and tcY-NH2 reduced Ca2+ mobilization induced by thrombin, and depletion of the DTS after desensitization or blockade of PAR-1 and PAR-4 had no significant effect on Ca2+ release stimulated by thrombin through the GPIb-IX-V receptor. Converse experiments showed that depletion of the acidic stores using TBHQ reduced Ca2+ release evoked by SFLLRN or AYPGKF, by 20 and 50% respectively, and abolished thrombin-stimulated Ca2+ release through the GPIb-IX-V receptor when PAR-1 and PAR-4 had been desensitized or blocked. Our results indicate that thrombin-induced activation of PAR-1 and PAR-4 evokes Ca2+ release from both Ca2+ stores, while activation of GPIb-IX-V by thrombin releases Ca2+ solely from the acidic compartments in human platelets.
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Affiliation(s)
- Isaac Jardin
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Nidhal Ben Amor
- †Unité de Recherche de Biochimie, Inst. Superieur de Biotechnologie, Monastir, Tunisia
| | - Ahgleb Bartegi
- †Unité de Recherche de Biochimie, Inst. Superieur de Biotechnologie, Monastir, Tunisia
| | - José A. Pariente
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Ginés M. Salido
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Juan A. Rosado
- *Cell Physiology Research Group, Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
- To whom correspondence should be addressed (email )
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Atucha NM, Iyú D, Alcaraz A, Rosa V, Martínez-Prieto C, Ortiz MC, Rosado JA, García-Estañ J. Altered calcium signalling in platelets from bile-duct-ligated rats. Clin Sci (Lond) 2007; 112:167-74. [PMID: 16948638 DOI: 10.1042/cs20060226] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present study, we have analysed the mechanisms of Ca2+ entry and release in platelets obtained from BDL (bile-duct-ligated) rats, 11–13 days and 4 weeks after surgery. Platelets were washed and loaded with fura-2, and [Ca2+]i (cytosolic Ca2+ concentration) was determined in cell suspensions by means of fluorescence spectroscopy. Basal [Ca2+]i was similar in platelets from BDL rats compared with those from their respective controls, both in the absence and presence of extracellular Ca2+. Platelet stimulation with thrombin in the absence and presence of extracellular Ca2+ induced a rapid rise in [Ca2+]i that was of greater magnitude in platelets from BDL rats than in controls. Ca2+ storage was significantly elevated in platelets from BDL rats, as well as the activity of SERCA (sarcoplasmic/endoplasmic-reticulum Ca2+-ATPase). Capacitative Ca2+ entry, as evaluated by inhibition of SERCA with thapsigargin, was also altered in platelets from BDL rats, having lower rates of Ca2+ entry. In conclusion, chronic BDL alters intracellular Ca2+ homoeostasis in platelets, such that an enhanced Ca2+ release is evoked by thrombin, which may be due to an increased amount of Ca2+ stored in the intracellular organelles and secondary to an enhanced activity of SERCA. These alterations are already evident before cirrhosis has completely developed and occurs during the cholestasis phase.
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Affiliation(s)
- Noemí M Atucha
- Department of Physiology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain.
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Abstract
The sarcoendoplasmic reticulum (SR) calcium transport ATPase (SERCA) is a pump that transports calcium ions from the cytoplasm into the SR. It is present in both animal and plant cells, although knowledge of SERCA in the latter is scant. The pump shares the catalytic properties of ion-motive ATPases of the P-type family, but has distinctive regulation properties. The SERCA pump is encoded by a family of three genes, SERCA1, 2, and 3, that are highly conserved but localized on different chromosomes. The SERCA isoform diversity is dramatically enhanced by alternative splicing of the transcripts, occurring mainly at the COOH-terminal. At present, more than 10 different SERCA isoforms have been detected at the protein level. These isoforms exhibit both tissue and developmental specificity, suggesting that they contribute to unique physiological properties of the tissue in which they are expressed. The function of the SERCA pump is modulated by the endogenous molecules phospholamban (PLB) and sarcolipin (SLN), expressed in cardiac and skeletal muscles. The mechanism of action of PLB on SERCA is well characterized, whereas that of SLN is only beginning to be understood. Because the SERCA pump plays a major role in muscle contraction, a number of investigations have focused on understanding its role in cardiac and skeletal muscle disease. These studies document that SERCA pump expression and activity are decreased in aging and in a variety of pathophysiological conditions including heart failure. Recently, SERCA pump gene transfer was shown to be effective in restoring contractile function in failing heart muscle, thus emphasizing its importance in muscle physiology and its potential use as a therapeutic agent.
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Affiliation(s)
- Muthu Periasamy
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, Ohio 43210, USA
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Dally S, Bredoux R, Corvazier E, Andersen J, Clausen J, Dode L, Fanchaouy M, Gelebart P, Monceau V, Del Monte F, Gwathmey J, Hajjar R, Chaabane C, Bobe R, Raies A, Enouf J. Ca2+-ATPases in non-failing and failing heart: evidence for a novel cardiac sarco/endoplasmic reticulum Ca2+-ATPase 2 isoform (SERCA2c). Biochem J 2006; 395:249-58. [PMID: 16402920 PMCID: PMC1422767 DOI: 10.1042/bj20051427] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 12/08/2005] [Accepted: 01/11/2006] [Indexed: 01/24/2023]
Abstract
We recently documented the expression of a novel human mRNA variant encoding a yet uncharacterized SERCA [SR (sarcoplasmic reticulum)/ER (endoplasmic reticulum) Ca2+-ATPase] protein, SERCA2c [Gélébart, Martin, Enouf and Papp (2003) Biochem. Biophys. Res. Commun. 303, 676-684]. In the present study, we have analysed the expression and functional characteristics of SERCA2c relative to SERCA2a and SERCA2b isoforms upon their stable heterologous expression in HEK-293 cells (human embryonic kidney 293 cells). All SERCA2 proteins induced an increased Ca2+ content in the ER of intact transfected cells. In microsomes prepared from transfected cells, SERCA2c showed a lower apparent affinity for cytosolic Ca2+ than SERCA2a and a catalytic turnover rate similar to SERCA2b. We further demonstrated the expression of the endogenous SERCA2c protein in protein lysates isolated from heart left ventricles using a newly generated SERCA2c-specific antibody. Relative to the known uniform distribution of SERCA2a and SERCA2b in cardiomyocytes of the left ventricle tissue, SERCA2c was only detected in a confined area of cardiomyocytes, in close proximity to the sarcolemma. This finding led us to explore the expression of the presently known cardiac Ca2+-ATPase isoforms in heart failure. Comparative expression of SERCAs and PMCAs (plasma-membrane Ca2+-ATPases) was performed in four nonfailing hearts and five failing hearts displaying mixed cardiomyopathy and idiopathic dilated cardiomyopathies. Relative to normal subjects, cardiomyopathic patients express more PMCAs than SERCA2 proteins. Interestingly, SERCA2c expression was significantly increased (166+/-26%) in one patient. Taken together, these results demonstrate the expression of the novel SERCA2c isoform in the heart and may point to a still unrecognized role of PMCAs in cardiomyopathies.
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Key Words
- endoplasmic reticulum
- heart failure
- human embryonic kidney 293 cell (hek-293 cell)
- isoform
- plasma membrane ca2+-atpase (pmca)
- sarco/endoplasmic reticulum ca2+-atpase (serca)
- er, endoplasmic reticulum
- [ca2+]c, cytosolic ca2+ concentration
- [ca2+]er, er ca2+ content
- fura 2/am, fura 2 acetoxymethyl ester
- gapdh, glyceraldehyde-3-phosphate dehydrogenase
- hek-293 cell, human embryonic kidney 293 cell
- nnos, neuronal nitric oxide synthase
- pmca, plasma-membrane ca2+-atpase
- rt, reverse transcriptase
- sr, sarcoplasmic reticulum
- serca, sr/er ca2+-atpase
- spca, secretory-pathway ca2+-atpase
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Affiliation(s)
- Saoussen Dally
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Raymonde Bredoux
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Elisabeth Corvazier
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Jens P. Andersen
- †Department of Physiology, Institute of Physiology and Biophysics, University of Aarhus, Aarhus, Denmark
| | - Johannes D. Clausen
- †Department of Physiology, Institute of Physiology and Biophysics, University of Aarhus, Aarhus, Denmark
| | - Leonard Dode
- ‡Laboratory of Physiology, Catholic University of Leuven, Leuven, Belgium
| | - Mohammed Fanchaouy
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Pascal Gelebart
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Virginie Monceau
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Frederica Del Monte
- §Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, U.S.A
| | - Judith K. Gwathmey
- §Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, U.S.A
| | - Roger Hajjar
- §Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, U.S.A
| | - Chiraz Chaabane
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Régis Bobe
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | - Aly Raies
- ∥Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Tunisia
| | - Jocelyne Enouf
- *INSERM U689, IFR139, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
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López J, Camello-Almaraz C, Pariente J, Salido G, Rosado J. Ca2+ accumulation into acidic organelles mediated by Ca2+- and vacuolar H+-ATPases in human platelets. Biochem J 2005; 390:243-52. [PMID: 15847604 PMCID: PMC1188269 DOI: 10.1042/bj20050168] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/19/2005] [Accepted: 04/22/2005] [Indexed: 11/17/2022]
Abstract
Most physiological agonists increase cytosolic free [Ca2+]c (cytosolic free Ca2+ concentration) to regulate a variety of cellular processes. How different stimuli evoke distinct spatiotemporal Ca2+ responses remains unclear, and the presence of separate intracellular Ca2+ stores might be of great functional relevance. Ca2+ accumulation into intracellular compartments mainly depends on the activity of Ca2+- and H+-ATPases. Platelets present two separate Ca2+ stores differentiated by the distinct sensitivity to thapsigargin and TBHQ [2,5-di-(t-butyl)-1,4-hydroquinone]. Although one store has long been identified as the dense tubular system, the nature of the TBHQ-sensitive store remains uncertain. Treatment of platelets with GPN (glycylphenylalanine-2-naphthylamide) impaired Ca2+ release by TBHQ and reduced that evoked by thrombin. In contrast, GPN did not modify Ca2+ mobilization stimulated by ADP or AVP ([arginine]vasopressin). Treatment with nigericin, a proton carrier, and bafilomycin A1, an inhibitor of the vacuolar H+-ATPase, to dissipate the proton gradient into acidic organelles induces a transient increase in [Ca2+]c that was abolished by previous treatment with the SERCA (sarcoplasmic/endoplasmic-reticulum Ca2+-ATPase) 3 inhibitor TBHQ. Depleted acidic stores after nigericin or bafilomycin A1 were refilled by SERCA 3. Thrombin, but not ADP or AVP, reduces the rise in [Ca2+]c evoked by nigericin and bafilomycin A1. Our results indicate that the TBHQ-sensitive store in human platelets is an acidic organelle whose Ca2+ accumulation is regulated by both Ca2+- and vacuolar H+-ATPases.
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Key Words
- acidic organelles
- bafilomycin
- calcium stores
- nigericin
- platelets
- thrombin
- avp, [arginine]vasopressin
- [ca2+]c, cytosolic free calcium concentration
- er, endoplasmic reticulum
- gpn, glycylphenylalanine 2-naphthylamide
- hbs, hepes-buffered saline
- pmca, plasma-membrane ca2+ atpase
- serca 3, sarcoplasmic/endoplasmic-reticulum ca2+-atpase
- tbhq, 2,5-di-(t-butyl)-1,4-hydroquinone
- tg, thapsigargin
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Affiliation(s)
- José J. López
- Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | | | - José A. Pariente
- Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Ginés M. Salido
- Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
| | - Juan A. Rosado
- Department of Physiology, University of Extremadura, 10071 Cáceres, Spain
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López JJ, Redondo PC, Salido GM, Pariente JA, Rosado JA. Two distinct Ca2+ compartments show differential sensitivity to thrombin, ADP and vasopressin in human platelets. Cell Signal 2005; 18:373-81. [PMID: 16095882 DOI: 10.1016/j.cellsig.2005.05.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 05/06/2005] [Indexed: 11/16/2022]
Abstract
Recent studies propose the existence of two distinct Ca2+ compartments in human platelets based on the expression of different SERCA isoforms with distinct sensitivity to thapsigargin and 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ). Using fura-2-loaded human platelets we have found that depletion of the TBHQ sensitive store reduces thrombin--but not ADP--or vasopressin (AVP)-induced Ca2+ release. Redistribution of cytosolic Ca2+ after thrombin stimulation resulted in overloading of the TBHQ-sensitive store. This phenomenon was not observed with ADP or AVP. We found that NAADP decreases the Ca2+ concentration into the stores in permeabilized platelets, which is prevented by depletion of the TBHQ-sensitive store. Nimodipine, an inhibitor of the NAADP receptor, reduced thrombin-induced Ca2+ release from the TBHQ-sensitive stores, without having any effect on the responses elicited by ADP or AVP. Finally, the phospholipase C inhibitor, U-73122, abolished ADP- and AVP-induced Ca2+ release, suggesting that their responses are entirely dependent on IP3 generation. In contrast, treatment with both U-73122 and nimodipine was required to abolish thrombin-induced Ca2+ release. We suggest that thrombin evokes Ca2+ release from TBHQ-sensitive and insensitive stores, which requires both NAADP and IP3, respectively, while ADP and AVP exert an IP3-dependent release of Ca2+ from the TBHQ-insensitive compartment in human platelets.
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Affiliation(s)
- Jose J López
- Department of Physiology, University of Extremadura, Av. Universidad s/n, Cáceres 10071, Spain
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43
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Abstract
The sarco/endoplasmic reticulum (SR/ER) is the primary storage and release site of intracellular calcium (Ca2+) in many excitable cells. The SR is a tubular network, which in smooth muscle (SM) cells distributes close to cellular periphery (superficial SR) and in deeper aspects of the cell (deep SR). Recent attention has focused on the regulation of cell function by the superficial SR, which can act as a buffer and also as a regulator of membrane channels and transporters. Ca2+ is released from the SR via two types of ionic channels [ryanodine- and inositol 1,4,5-trisphosphate-gated], whereas accumulation from thecytoplasm occurs exclusively by an energy-dependent sarco-endoplasmic reticulum Ca2+-ATPase pump (SERCA). Within the SR, Ca2+ is bound to various storage proteins. Emerging evidence also suggests that the perinuclear portion of the SR may play an important role in nuclear transcription. In this review, we detail the pharmacology of agents that alter the functions of Ca2+ release channels and of SERCA. We describe their use and selectivity and indicate the concentrations used in investigating various SM preparations. Important aspects of cell regulation and excitation-contractile activity coupling in SM have been uncovered through the use of such activators and inhibitors of processes that determine SR function. Likewise, they were instrumental in the recent finding of an interaction of the SR with other cellular organelles such as mitochondria. Thus, an appreciation of the pharmacology and selectivity of agents that interfere with SR function in SM has greatly assisted in unveiling the multifaceted nature of the SR.
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Affiliation(s)
- Régent Laporte
- Ferring Research Institute, Inc., Ferring Pharmaceuticals, San Diego, California, USA
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44
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Bobe R, Bredoux R, Corvazier E, Andersen JP, Clausen JD, Dode L, Kovács T, Enouf J. Identification, Expression, Function, and Localization of a Novel (Sixth) Isoform of the Human Sarco/Endoplasmic Reticulum Ca2+ATPase 3 Gene. J Biol Chem 2004; 279:24297-306. [PMID: 15028735 DOI: 10.1074/jbc.m314286200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding of Ca(2+) signaling requires the knowledge of proteins involved in this process. Among these proteins are sarco/endoplasmic reticulum Ca(2+)-ATPases (SERCAs) that pump Ca(2+) into the endoplasmic reticulum (ER). Recently, the human SERCA3 gene was shown to give rise to five isoforms (SERCA3a-e (h3a-h3e)). Here we demonstrate the existence of an additional new member, termed SERCA3f (h3f). By reverse transcriptase-PCR using monocytic U937 cell RNA, h3f mRNA was found to exclude the antepenultimate exon 21. h3f mRNA expression appeared as a human-specific splice variant. It was not found in rats or mice. h3f mRNA gave rise to an h3f protein differing in its C terminus from h3a-h3e. Of particular interest, h3f diverged in the first amino acids after the first splice site but presented the same last 21 amino acids as h3b. Consequently, we further investigated the structure-function-location relationships of the h3b and h3f isoforms. Comparative functional study of h3b and h3f recombinant proteins in intact HEK-293 cells and in fractionated membranes showed the following distinct characteristics: (i) resting cytosolic Ca(2+) concentration ([Ca(2+)](c)) and (ii) ER Ca(2+) content ([Ca(2+)](er)); similar characteristics were shown for the following: (i) the effects of the SERCA inhibitor, thapsigargin, on Ca(2+) release ([Ca(2+)](Tg)) and subsequent Ca(2+) entry ([Ca(2+)](e)) and (ii) the low apparent Ca(2+) affinity and the enhanced rate of dephosphorylation of the E(2)P phosphoenzyme intermediate. Subcellular location of h3b and h3f by immunofluorescence and/or confocal microscopy using the h3b- and h3f-specific polyclonal and the pan-h3 monoclonal (PL/IM430) antibodies suggested overlapping but distinct ER location. The endogenous expression of h3f protein was also proved in U937 cells. Altogether these data suggest that the SERCA3 isoforms have a more widespread role in cellular Ca(2+) signaling than previously appreciated.
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Affiliation(s)
- Régis Bobe
- INSERM U.348, IFR6 Circulation Lariboisière, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
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Martin V, Bredoux R, Corvazier E, Van Gorp R, Kovacs T, Gelebart P, Enouf J. Three novel sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) 3 isoforms. Expression, regulation, and function of the membranes of the SERCA3 family. J Biol Chem 2002; 277:24442-52. [PMID: 11956212 DOI: 10.1074/jbc.m202011200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+-ATPases (SERCAs) pump Ca2+ into the endoplasmic reticulum. Recently, three human SERCA3 (h3a-c) proteins and a previously unknown rat SERCA3 (r3b/c) mRNA have been described. Here, we (i) document two novel human SERCA3 splice variants h3d and h3e, (ii) provide data for the expression and mechanisms regulating the expression of all known SERCA3 variants (r3a, r3b/c, and h3a-e), and (iii) show functional characteristics of the SERCA3 isoforms. h3d and h3e are issued from the insertion of an additional penultimate exon 22 resulting in different carboxyl termini for these variants. Distinct distribution patterns of the SERCA3 gene products were observed in a series of cell lines of hematopoietic, epithelial, embryonic origin, and several cancerous types, as well as in panels of rat and human tissues. Hypertension and protein kinase C, calcineurin, or retinoic acid receptor signaling pathways were found to differently control rat and human splice variant expression, respectively. Stable overexpression of each variant was performed in human embryonic kidney 293 cells, and the SERCA3 isoforms were fully characterized. All SERCA3 isoforms were found to pump Ca2+ with similar affinities. However, they modulated the cytosolic Ca2+ concentration ([Ca2+]c) and the endoplasmic reticulum Ca2+ content ([Ca2+]er) in different manners. A newly generated polyclonal antibody and a pan-SERCA3 antibody proved the endogenous expression of the three novel SERCA3 proteins, h3d, h3e, and r3b/c. All these data suggest that the SERCA3 gene products have a more widespread role in cellular Ca2+ signaling than previously appreciated.
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Affiliation(s)
- Virginie Martin
- INSERM U348, IFR6 Circulation Lariboisière, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
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Mountian I, Baba-Aïssa F, Jonas JC, Wuytack F, Parys JB. Expression of Ca(2+) Transport Genes in Platelets and Endothelial Cells in Hypertension. Hypertension 2001; 37:135-141. [PMID: 11208768 DOI: 10.1161/01.hyp.37.1.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
-Altered Ca(2+) handling is observed in different cells in essential hypertension. We investigated the expression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) and inositol 1,4,5-trisphosphate receptor (IP(3)R) isoforms in platelets and aortic endothelial cells (EC) isolated from spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats by ratio reverse-transcriptase-polymerase chain reaction (RT-PCR) analysis and Western blotting. SERCA2b and SERCA3 were assessed at mRNA (EC and platelets) and at protein level (platelets). IP(3)R1, IP(3)R2, and IP(3)R3 mRNAs were demonstrated in both cell types, but only IP(3)R1 and IP(3)R2 proteins were detected in platelets. Compared with WKY, SHR EC and platelets showed higher SERCA3 and IP(3)R2 expression and lower IP(3)R1 expression. We then investigated the effect of lisinopril (20 mg. kg(-)(1). d(-)(1); 10-week treatment of 4-week-old rats or 2-week treatment of adult rats) and captopril (100 mg. kg(-)(1). d(-)(1); 2-week treatment of adult rats). Consequently, expression patterns of SERCAs and IP(3)Rs were significantly modified. Except for SERCAs mRNA in platelets, all differences between SHR and WKY disappeared. However, SERCA3 remained the predominant isoform. Both EC and platelets demonstrated a high equal expression of IP(3)R2 mRNA. IP(3)R1 was the predominant platelet protein isoform, as it was in untreated WKY. mRNA was also isolated from pancreatic islets of WKY and SHR, but no effect of either rat strain or of lisinopril treatment was observed on the expression of the studied genes. We hypothesize that the identical expression pattern of SERCAs and IP(3)Rs after treatment with ACE inhibitors represents a different nonhypertensive configuration, which, through changes in intracellular Ca(2+) handling, improves endothelial and platelet dysfunction in SHR but has no effect in WKY.
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Affiliation(s)
- Irina Mountian
- Laboratorium voor Fysiologie (I.M., H.De S., F.W., J.B.P.), KU Leuven, Leuven, Belgium
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Abstract
Mammalian skeletal muscle shows an enormous variability in its functional features such as rate of force production, resistance to fatigue, and energy metabolism, with a wide spectrum from slow aerobic to fast anaerobic physiology. In addition, skeletal muscle exhibits high plasticity that is based on the potential of the muscle fibers to undergo changes of their cytoarchitecture and composition of specific muscle protein isoforms. Adaptive changes of the muscle fibers occur in response to a variety of stimuli such as, e.g., growth and differentition factors, hormones, nerve signals, or exercise. Additionally, the muscle fibers are arranged in compartments that often function as largely independent muscular subunits. All muscle fibers use Ca(2+) as their main regulatory and signaling molecule. Therefore, contractile properties of muscle fibers are dependent on the variable expression of proteins involved in Ca(2+) signaling and handling. Molecular diversity of the main proteins in the Ca(2+) signaling apparatus (the calcium cycle) largely determines the contraction and relaxation properties of a muscle fiber. The Ca(2+) signaling apparatus includes 1) the ryanodine receptor that is the sarcoplasmic reticulum Ca(2+) release channel, 2) the troponin protein complex that mediates the Ca(2+) effect to the myofibrillar structures leading to contraction, 3) the Ca(2+) pump responsible for Ca(2+) reuptake into the sarcoplasmic reticulum, and 4) calsequestrin, the Ca(2+) storage protein in the sarcoplasmic reticulum. In addition, a multitude of Ca(2+)-binding proteins is present in muscle tissue including parvalbumin, calmodulin, S100 proteins, annexins, sorcin, myosin light chains, beta-actinin, calcineurin, and calpain. These Ca(2+)-binding proteins may either exert an important role in Ca(2+)-triggered muscle contraction under certain conditions or modulate other muscle activities such as protein metabolism, differentiation, and growth. Recently, several Ca(2+) signaling and handling molecules have been shown to be altered in muscle diseases. Functional alterations of Ca(2+) handling seem to be responsible for the pathophysiological conditions seen in dystrophinopathies, Brody's disease, and malignant hyperthermia. These also underline the importance of the affected molecules for correct muscle performance.
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Affiliation(s)
- M W Berchtold
- Department of Molecular Cell Biology, Institute of Molecular Biology, University of Copenhagen, Copenhagen, Denmark.
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Gayan-Ramirez G, Vanzeir L, Wuytack F, Decramer M. Corticosteroids decrease mRNA levels of SERCA pumps, whereas they increase sarcolipin mRNA in the rat diaphragm. J Physiol 2000; 524 Pt 2:387-97. [PMID: 10766920 PMCID: PMC2269887 DOI: 10.1111/j.1469-7793.2000.t01-2-00387.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
1. In order to explore the potential role of the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase (SERCA)-type pumps and of their modulators phospholamban (PLB) and sarcolipin (SLN) in the functional alterations of the diaphragm induced by corticosteroid treatment, expression of SERCA, PLB and SLN was assessed by RT-PCR in the diaphragm of rats treated daily for 5 days either with triamcinolone (80 mg kg-1, n = 8) or with saline (control; 0.6 ml, n = 8). 2. Triamcinolone treatment reduced the normalised overall amount of all SERCA mRNA in diaphragm by 70 % compared to controls (P < 0.05). This reduction was accounted for by a relatively larger decrease in the SERCA1 mRNA (-69 %, P < 0.05) whilst the decrease in SERCA2 mRNA (-49 %, P = 0.09) did not reach statistical significance. As a result the relative proportion of SERCA2 mRNA was increased from 43 +/- 7 % in control diaphragm to 52 +/- 4 % after triamcinolone treatment (P < 0.05). 3. Only the adult isoform of SERCA1 (i.e. SERCA1a) mRNA was found in the diaphragm of the 15-week-old control rats. Furthermore, triamcinolone treatment resulted in reduced levels of SERCA2a (-40 %, P < 0.05) and increased levels of SLN mRNA (+100 %, P < 0.05), while the decrease in PLB mRNA (-31 %, P = 0.277) did not reach statistical significance. SERCA1b, SERCA2b and SERCA3 mRNA levels fell below the detection limit in the diaphragm of both control and triamcinolone-treated rats. 4. Compared to control diaphragm, control rat heart showed a relatively high PLB/(SERCA1 + SERCA2) mRNA ratio of 7.88 while this ratio amounted only to 0.16 in control extensor digitorum longus (EDL) muscle. Remarkably, the SLN/(SERCA1 + SERCA2) mRNA ratio in normal cardiac muscle (0.96) was nearly the same as in diaphragm, but in EDL it amounted to only 0.05 that in diaphragm. This indicates the very low expression of SLN in rat EDL. 5. These data reveal that considerable alterations in SERCA mRNA levels accompany the functional changes seen in diaphragm after corticosteroid treatment. The relatively larger decrease in SERCA1 mRNA is in agreement with the selective type II fibre atrophy previously observed in the diaphragm of triamcinolone-treated rats, but the magnitude of SERCA alterations is more pronounced than expected on the basis of the structural changes in the diaphragm. The increase in SLN mRNA levels may represent a compensatory mechanism.
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Affiliation(s)
- G Gayan-Ramirez
- Respiratory Muscle Research Unit, Laboratory of Pneumology and Laboratory of Physiology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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Martin V, Bredoux R, Corvazier E, Papp B, Enouf J. Platelet Ca(2+)ATPases : a plural, species-specific, and multiple hypertension-regulated expression system. Hypertension 2000; 35:91-102. [PMID: 10642281 DOI: 10.1161/01.hyp.35.1.91] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gaining insight into nonmuscle Ca(2+) signaling requires basic knowledge of the major structures involved. We investigated the expression of platelet Ca(2+)ATPases in normal and hypertension-associated abnormal Ca(2+) signaling. First, overall identification of normotensive Wistar-Kyoto rat Ca(2+)ATPases was attempted by looking for newly described human platelet 3'-end alternatively spliced sarco/endoplasmic reticulum Ca(2+)ATPases (SERCA) 3b mRNA and plasma membrane Ca(2+)ATPase (PMCA) 1b and 4b proteins, in addition to SERCA2b and SERCA3a isoforms. For SERCAs, comparative analyses of human and Wistar-Kyoto rat SERCA3 platelet mRNA by reverse transcription-polymerase chain reaction (RT-PCR) followed by sequencing established that human platelets coexpressed SERCA3b and a third SERCA3c, while rat cells were devoid of them but expressed a still unknown splice variant that we termed rSERCA3b/3c. Its identification using 3'-end SERCA3 gene and rapid amplification of cDNA ends (RACE)-PCR studies showed that it results from an additional SERCA3 alternative splicing process, which uses a second alternative polyadenylation site located in the last intron. For PMCAs, with the use of gene-specific RT-PCR followed by sequencing and Western blotting using 5F10 monoclonal antibody, expression of human and rat platelet PMCA1b and PMCA4b was similar. Second, comparative analysis of these newly identified Ca(2+)ATPases and SERCA3a in age-matched spontaneously hypertensive rat platelets demonstrated (1) a marked downregulation of rSERCA3b/3c, which became null, and a 1.71-fold increase in SERCA3a and (2) an opposite regulation of the 2 PMCAs, namely, a 3.3-fold decrease in PMCA1b mRNA and a 3.7-fold increase in PMCA4b mRNA. Hence, platelets coexpress multiple, diverse, and species-specific Ca(2+)ATPases, including a novel fourth SERCA3. Moreover, expression of PMCA (1b and 4b), SERCA3a, and rSERCA3b/3c was modulated in rat hypertension. Hence, Ca(2+)ATPases should be regarded as constituting a new rational basis for the understanding of nonmuscle cell Ca(2+) signaling.
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Affiliation(s)
- V Martin
- U348 INSERM, IFR Circulation Lariboisière, Hôpital Lariboisière, Paris, France
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Mitidieri F, de Meis L. Ca(2+) release and heat production by the endoplasmic reticulum Ca(2+)-ATPase of blood platelets. Effect of the platelet activating factor. J Biol Chem 1999; 274:28344-50. [PMID: 10497193 DOI: 10.1074/jbc.274.40.28344] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Different sarco/endoplasmic reticulum Ca(2+)-ATPases isoforms are found in blood platelets and in skeletal muscle. The amount of heat produced during ATP hydrolysis by vesicles derived from the endoplasmic reticulum of blood platelets was the same in the absence and presence of a transmembrane Ca(2+) gradient. Addition of platelets activating factor (PAF) to the medium promoted both a Ca(2+) efflux that was arrested by thapsigargin and an increase of the yield of heat produced during ATP hydrolysis. The calorimetric enthalpy of ATP hydrolysis (DeltaH(cal)) measured during Ca(2+) transport varied between -10 and -12 kcal/mol without PAF and between -20 and -24 kcal/mol with 4 microM PAF. Different from platelets, in skeletal muscle vesicles a thapsigargin-sensitive Ca(2+) efflux and a high heat production during ATP hydrolysis were measured without PAF and the DeltaH(cal) varied between -10 and -12 kcal/mol in the absence of Ca(2+) and between -22 up to -32 kcal/mol after formation of a transmembrane Ca(2+) gradient. PAF did not enhance the rate of thapsigargin-sensitive Ca(2+) efflux nor increase the yield of heat produced during ATP hydrolysis. These findings indicate that the platelets of Ca(2+)-ATPase isoforms are only able to convert osmotic energy into heat in the presence of PAF.
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Affiliation(s)
- F Mitidieri
- Instituto de Ciências Biomédicas, Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brasil
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