1
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Sneyers F, Speelman-Rooms F, Verhelst SHL, Bootman MD, Bultynck G. Cellular effects of BAPTA: Are they only about Ca 2+ chelation? BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119589. [PMID: 37739271 DOI: 10.1016/j.bbamcr.2023.119589] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/06/2023] [Accepted: 09/10/2023] [Indexed: 09/24/2023]
Abstract
Intracellular Ca2+ signals play a vital role in a broad range of cell biological and physiological processes in all eukaryotic cell types. Dysregulation of Ca2+ signaling has been implicated in numerous human diseases. Over the past four decades, the understanding of how cells use Ca2+ as a messenger has flourished, largely because of the development of reporters that enable visualization of Ca2+ signals in different cellular compartments, and tools that can modulate cellular Ca2+ signaling. One such tool that is frequently used is BAPTA; a fast, high-affinity Ca2+-chelating molecule. By making use of a cell-permeable acetoxymethyl ester (AM) variant, BAPTA can be readily loaded into the cytosol of cells (referred to as BAPTAi), where it is trapped and able to buffer changes in cytosolic Ca2+. Due to the ease of loading of the AM version of BAPTA, this reagent has been used in hundreds of studies to probe the role of Ca2+ signaling in specific processes. As such, for decades, researchers have almost universally attributed changes in biological processes caused by BAPTAi to the involvement of Ca2+ signaling. However, BAPTAi has often been used without any form of control, and in many cases has neither been shown to be retained in cells for the duration of experiments nor to buffer any Ca2+ signals. Moreover, increasing evidence points to off-target cellular effects of BAPTA that are clearly not related to Ca2+ chelation. Here, we briefly introduce Ca2+ signaling and the history of Ca2+ chelators and fluorescent Ca2+ indicators. We highlight Ca2+-independent effects of BAPTAi on a broad range of molecular targets and describe some of BAPTAi's impacts on cell functions that occur independently of its Ca2+-chelating properties. Finally, we propose strategies for determining whether Ca2+ chelation, the binding of other metal ions, or off-target interactions with cell components are responsible for BAPTAi's effect on a particular process and suggest some future research directions.
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Affiliation(s)
- Flore Sneyers
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000 Leuven, Belgium
| | - Femke Speelman-Rooms
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000 Leuven, Belgium; KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestraat 49 box 901b, B-3000 Leuven, Belgium
| | - Steven H L Verhelst
- KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestraat 49 box 901b, B-3000 Leuven, Belgium
| | - Martin D Bootman
- The Open University, Cancer Research Group, School of Life, Health and Chemical Sciences, Milton Keynes, UK
| | - Geert Bultynck
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000 Leuven, Belgium.
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2
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Kolesnikov DO, Nomerovskaya MA, Grigorieva ER, Reshetin DS, Skobeleva KV, Gusev KO, Shalygin AV, Kaznacheyeva EV. Calcium chelation independent effects of BAPTA on endogenous ANO6 channels in HEK293T cells. Biochem Biophys Res Commun 2024; 693:149378. [PMID: 38100999 DOI: 10.1016/j.bbrc.2023.149378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 12/09/2023] [Indexed: 12/17/2023]
Abstract
Selective calcium chelator 1,2-Bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA) is a common tool to investigate calcium signaling. However, BAPTA expresses various effects on intracellular calcium signaling, which are not related to its ability to bind Ca2+. In patch clamp experiments, we investigated calcium chelation independent effects of BAPTA on endogenous calcium-activated chloride channels ANO6 (TMEM16F) in HEK293T cells. We have found that application of BAPTA to intracellular solution led to two distinct effects on channels properties. On the one hand, application of BAPTA acutely reduced amplitude of endogenous ANO6 channels induced by 10 μM Ca2+ in single channel recordings. On the other hand, BAPTA application by itself induced ANO6 channel activity in the absence of the intracellular calcium elevation. Open channel probability was enhanced by increasing the intracellular BAPTA concentration from 0.1 to 1 and 10 mM. Another calcium chelator EGTA did not demonstrate chelation independent effects on the ANO6 activity in the same conditions. Due to off-target effects BAPTA should be used with caution when studying calcium-activated ANO6 channels.
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Affiliation(s)
- D O Kolesnikov
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - M A Nomerovskaya
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - E R Grigorieva
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - D S Reshetin
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - K V Skobeleva
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - K O Gusev
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation
| | - A V Shalygin
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
| | - E V Kaznacheyeva
- Institute of Cytology RAS, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
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3
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Iyer M, Kantarci H, Cooper MH, Ambiel N, Novak SW, Andrade LR, Lam M, Jones G, Münch AE, Yu X, Khakh BS, Manor U, Zuchero JB. Oligodendrocyte calcium signaling promotes actin-dependent myelin sheath extension. Nat Commun 2024; 15:265. [PMID: 38177161 PMCID: PMC10767123 DOI: 10.1038/s41467-023-44238-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Myelin is essential for rapid nerve signaling and is increasingly found to play important roles in learning and in diverse diseases of the CNS. Morphological parameters of myelin such as sheath length are thought to precisely tune conduction velocity, but the mechanisms controlling sheath morphology are poorly understood. Local calcium signaling has been observed in nascent myelin sheaths and can be modulated by neuronal activity. However, the role of calcium signaling in sheath formation remains incompletely understood. Here, we use genetic tools to attenuate oligodendrocyte calcium signaling during myelination in the developing mouse CNS. Surprisingly, genetic calcium attenuation does not grossly affect the number of myelinated axons or myelin thickness. Instead, calcium attenuation causes myelination defects resulting in shorter, dysmorphic sheaths. Mechanistically, calcium attenuation reduces actin filaments in oligodendrocytes, and an intact actin cytoskeleton is necessary and sufficient to achieve accurate myelin morphology. Together, our work reveals a cellular mechanism required for accurate CNS myelin formation and may provide mechanistic insight into how oligodendrocytes respond to neuronal activity to sculpt and refine myelin sheaths.
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Affiliation(s)
- Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Husniye Kantarci
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Madeline H Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Nicholas Ambiel
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Sammy Weiser Novak
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Leonardo R Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Mable Lam
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Graham Jones
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Alexandra E Münch
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Xinzhu Yu
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-, Champaign, IL, USA
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Cell and Developmental Biology, University of California, San Diego, San Diego, CA, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
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4
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Schumacher S, Tahiri H, Ezan P, Rouach N, Witschas K, Leybaert L. Inhibiting astrocyte connexin-43 hemichannels blocks radiation-induced vesicular VEGF-A release and blood-brain barrier dysfunction. Glia 2024; 72:34-50. [PMID: 37670489 DOI: 10.1002/glia.24460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 09/07/2023]
Abstract
Therapeutic brain irradiation with ionizing radiation exerts multiple side effects including barrier leakage that disturbs glial-neuronal functioning and may affect cognition. Astrocytes contribute to barrier leakage by endfeet release of various vasoactive substances acting on capillary endothelial cells forming the barrier. Here, we investigated X-ray effects on astrocytic vesicular transport in mice and determined whether interfering with astrocyte connexins affects radiation-induced barrier leakage. We found that astrocytic VEGF-A-loaded VAMP3 vesicles drastically reorganize starting from 6 h post-irradiation and move in a calcium- and Cx43-dependent manner towards endfeet where VEGF-A is released, provoking barrier leakage. Vesicular transport activation, VEGF-A release and leakage 24 h post-irradiation were all potently inhibited by astrocytic Cx43 KO, Cx43S255/262/279/282A (MK4) mutant mice and TATGap19 inhibition of Cx43 hemichannel opening. Astrocyte VEGF release is a major player in complications of brain irradiation, which can be mitigated by anti-VEGF treatments. Targeting Cx43 hemichannels allows to prevent astrocyte VEGF release at an early stage after brain irradiation.
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Affiliation(s)
- Steffi Schumacher
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Hanane Tahiri
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
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5
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Sneyers F, Kerkhofs M, Speelman-Rooms F, Welkenhuyzen K, La Rovere R, Shemy A, Voet A, Eelen G, Dewerchin M, Tait SWG, Ghesquière B, Bootman MD, Bultynck G. Intracellular BAPTA directly inhibits PFKFB3, thereby impeding mTORC1-driven Mcl-1 translation and killing MCL-1-addicted cancer cells. Cell Death Dis 2023; 14:600. [PMID: 37684238 PMCID: PMC10491774 DOI: 10.1038/s41419-023-06120-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 08/10/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
Intracellular Ca2+ signals control several physiological and pathophysiological processes. The main tool to chelate intracellular Ca2+ is intracellular BAPTA (BAPTAi), usually introduced into cells as a membrane-permeant acetoxymethyl ester (BAPTA-AM). Previously, we demonstrated that BAPTAi enhanced apoptosis induced by venetoclax, a BCL-2 antagonist, in diffuse large B-cell lymphoma (DLBCL). This finding implied a novel interplay between intracellular Ca2+ signaling and anti-apoptotic BCL-2 function. Hence, we set out to identify the underlying mechanisms by which BAPTAi enhances cell death in B-cell cancers. In this study, we discovered that BAPTAi alone induced apoptosis in hematological cancer cell lines that were highly sensitive to S63845, an MCL-1 antagonist. BAPTAi provoked a rapid decline in MCL-1-protein levels by inhibiting mTORC1-driven Mcl-1 translation. These events were not a consequence of cell death, as BAX/BAK-deficient cancer cells exhibited similar downregulation of mTORC1 activity and MCL-1-protein levels. Next, we investigated how BAPTAi diminished mTORC1 activity and identified its ability to impair glycolysis by directly inhibiting 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) activity, a previously unknown effect of BAPTAi. Notably, these effects were also induced by a BAPTAi analog with low affinity for Ca2+. Consequently, our findings uncover PFKFB3 inhibition as an Ca2+-independent mechanism through which BAPTAi impairs cellular metabolism and ultimately compromises the survival of MCL-1-dependent cancer cells. These findings hold two important implications. Firstly, the direct inhibition of PFKFB3 emerges as a key regulator of mTORC1 activity and a promising target in MCL-1-dependent cancers. Secondly, cellular effects caused by BAPTAi are not necessarily related to Ca2+ signaling. Our data support the need for a reassessment of the role of Ca2+ in cellular processes when findings were based on the use of BAPTAi.
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Affiliation(s)
- Flore Sneyers
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium
| | - Martijn Kerkhofs
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium
| | - Femke Speelman-Rooms
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium
- KU Leuven, Laboratory of Chemical Biology, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I bis, Herestraat 49 box 901, 3000, Leuven, Belgium
| | - Kirsten Welkenhuyzen
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium
| | - Rita La Rovere
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium
| | - Ahmed Shemy
- KU Leuven, Laboratory for Biomolecular Modelling and Design, Department of Chemistry, Celestijnenlaan 200G, 3001, Heverlee, Belgium
| | - Arnout Voet
- KU Leuven, Laboratory for Biomolecular Modelling and Design, Department of Chemistry, Celestijnenlaan 200G, 3001, Heverlee, Belgium
| | - Guy Eelen
- KU Leuven, Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, Leuven Cancer Institute, Campus Gasthuisberg O&N4, Herestraat 49 box 912, Leuven, Belgium
- VIB-KU Leuven, Center for Cancer Biology, Laboratory of Angiogenesis and Vascular Metabolism, Campus Gasthuisberg O&N4, Herestraat 49 box 912, 3000, Leuven, Belgium
| | - Mieke Dewerchin
- KU Leuven, Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, Leuven Cancer Institute, Campus Gasthuisberg O&N4, Herestraat 49 box 912, Leuven, Belgium
- VIB-KU Leuven, Center for Cancer Biology, Laboratory of Angiogenesis and Vascular Metabolism, Campus Gasthuisberg O&N4, Herestraat 49 box 912, 3000, Leuven, Belgium
| | - Stephen W G Tait
- Cancer Research UK Beatson Institute, School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Bart Ghesquière
- KU Leuven, Laboratory of Applied Mass Spectrometry, Department of Cellular and Molecular Medicine, Leuven, Belgium - VIB, Metabolomics Core Facility Leuven, Center for Cancer Biology, Leuven, Belgium, Herestraat 49 box 912, 3000, Leuven, Belgium
| | - Martin D Bootman
- School of Life, Health and Chemical Sciences, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I, Herestraat 49 box 802, 3000, Leuven, Belgium.
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6
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Iyer M, Kantarci H, Ambiel N, Novak SW, Andrade LR, Lam M, Münch AE, Yu X, Khakh BS, Manor U, Zuchero JB. Oligodendrocyte calcium signaling sculpts myelin sheath morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536299. [PMID: 37090556 PMCID: PMC10120717 DOI: 10.1101/2023.04.11.536299] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Myelin is essential for rapid nerve signaling and is increasingly found to play important roles in learning and in diverse diseases of the CNS. Morphological parameters of myelin such as sheath length and thickness are regulated by neuronal activity and can precisely tune conduction velocity, but the mechanisms controlling sheath morphology are poorly understood. Local calcium signaling has been observed in nascent myelin sheaths and can be modulated by neuronal activity. However, the role of calcium signaling in sheath formation and remodeling is unknown. Here, we used genetic tools to attenuate oligodendrocyte calcium signaling during active myelination in the developing mouse CNS. Surprisingly, we found that genetic calcium attenuation did not grossly affect the number of myelinated axons or myelin thickness. Instead, calcium attenuation caused striking myelination defects resulting in shorter, dysmorphic sheaths. Mechanistically, calcium attenuation reduced actin filaments in oligodendrocytes, and an intact actin cytoskeleton was necessary and sufficient to achieve accurate myelin morphology. Together, our work reveals a novel cellular mechanism required for accurate CNS myelin formation and provides mechanistic insight into how oligodendrocytes may respond to neuronal activity to sculpt myelin sheaths throughout the nervous system.
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7
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Varadarajan S, Chumki SA, Stephenson RE, Misterovich ER, Wu JL, Dudley CE, Erofeev IS, Goryachev AB, Miller AL. Mechanosensitive calcium flashes promote sustained RhoA activation during tight junction remodeling. J Cell Biol 2022; 221:213049. [PMID: 35254388 PMCID: PMC8906493 DOI: 10.1083/jcb.202105107] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 12/03/2021] [Accepted: 02/02/2022] [Indexed: 11/22/2022] Open
Abstract
Epithelial cell–cell junctions remodel in response to mechanical stimuli to maintain barrier function. Previously, we found that local leaks in tight junctions (TJs) are rapidly repaired by local, transient RhoA activation, termed “Rho flares,” but how Rho flares are regulated is unknown. Here, we discovered that intracellular calcium flashes and junction elongation are early events in the Rho flare pathway. Both laser-induced and naturally occurring TJ breaks lead to local calcium flashes at the site of leaks. Additionally, junction elongation induced by optogenetics increases Rho flare frequency, suggesting that Rho flares are mechanically triggered. Depletion of intracellular calcium or inhibition of mechanosensitive calcium channels (MSCs) reduces the amplitude of calcium flashes and diminishes the sustained activation of Rho flares. MSC-dependent calcium influx is necessary to maintain global barrier function by regulating reinforcement of local TJ proteins via junction contraction. In all, we uncovered a novel role for MSC-dependent calcium flashes in TJ remodeling, allowing epithelial cells to repair local leaks induced by mechanical stimuli.
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Affiliation(s)
| | - Shahana A Chumki
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI
| | - Rachel E Stephenson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Eileen R Misterovich
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Jessica L Wu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Claire E Dudley
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Ivan S Erofeev
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, Scotland
| | - Andrew B Goryachev
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, Scotland
| | - Ann L Miller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI
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8
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Xu Y, Chen J, Chen J, Teng J. EI24 promotes cell adaption to ER stress by coordinating IRE1 signaling and calcium homeostasis. EMBO Rep 2022; 23:e51679. [PMID: 35005829 PMCID: PMC8892245 DOI: 10.15252/embr.202051679] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a subcellular organelle crucial for protein folding and calcium storage. Accumulation of unfolded proteins or calcium depletion causes ER stress. Deficiency of ER stress adaptation leads to apoptosis, which is associated with several human disorders. Here, we reveal that ER transmembrane protein EI24 promotes cell adaptation to ER stress by coordinating the IRE1 branch of the unfolded protein response (UPR) and calcium signaling. Under nonstressed conditions, EI24 binds to the kinase domain of IRE1 to inhibit its activation. Upon ER stress, EI24 disassociates from IRE1 to permit UPR activation, and meanwhile targets IP3R1 to prevent ER calcium depletion, which together promote cell adaptation to ER stress. EI24 knockout causes failure of ER stress adaptation and apoptosis. Thus, EI24 is a novel anti-apoptotic factor implicated in ER stress signaling.
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Affiliation(s)
- Yiwei Xu
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of EducationCollege of Life SciencesPeking UniversityBeijingChina,Postdoctoral ProgrammeGuosen SecuritiesShenzhenChina
| | - Jie Chen
- Institute of Molecular MedicinePeking‐Tsinghua Center for Life SciencesAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijingChina
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of EducationCollege of Life SciencesPeking UniversityBeijingChina,Center for Quantitative BiologyPeking UniversityBeijingChina
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of EducationCollege of Life SciencesPeking UniversityBeijingChina
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9
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Rathinam E, Govindarajan S, Rajasekharan S, Declercq H, Elewaut D, De Coster P, Martens L, Leybaert L. The calcium dynamics of human dental pulp stem cells stimulated with tricalcium silicate-based cements determine their differentiation and mineralization outcome. Sci Rep 2021; 11:645. [PMID: 33436827 PMCID: PMC7804324 DOI: 10.1038/s41598-020-80096-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 12/03/2020] [Indexed: 12/19/2022] Open
Abstract
Calcium (Ca2+) signalling plays an indispensable role in dental pulp and dentin regeneration, but the Ca2+ responses of human dental pulp stem cells (hDPSCs) stimulated with tricalcium silicate-based (TCS-based) dental biomaterials remains largely unexplored. The objective of the present study was to identify and correlate extracellular Ca2+ concentration, intracellular Ca2+ dynamics, pH, cytotoxicity, gene expression and mineralization ability of human dental pulp stem cells (hDPSCs) stimulated with two different TCS-based biomaterials: Biodentine and ProRoot white MTA. The hDPSCs were exposed to the biomaterials, brought in contact with the overlaying medium, with subsequent measurements of extracellular Ca2+ and pH, and intracellular Ca2+ changes. Messenger RNA expression (BGLAP, TGF-β, MMP1 and BMP2), cytotoxicity (MTT and TUNEL) and mineralization potential (Alizarin red and Von Kossa staining) were then evaluated. Biodentine released significantly more Ca2+ in the α-MEM medium than ProRoot WMTA but this had no cytotoxic impact on hDPSCs. The larger Biodentine-linked Ca2+ release resulted in altered intracellular Ca2+ dynamics, which attained a higher maximum amplitude, faster rise time and increased area under the curve of the Ca2+ changes compared to ProRoot WMTA. Experiments with intracellular Ca2+ chelation, demonstrated that the biomaterial-triggered Ca2+ dynamics affected stem cell-related gene expression, cellular differentiation and mineralization potential. In conclusion, biomaterial-specific Ca2+ dynamics in hDPSCs determine differentiation and mineralization outcomes, with increased Ca2+ dynamics enhancing mineralization.
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Affiliation(s)
- Elanagai Rathinam
- Department of Paediatric Dentistry and Special Care, PAECOMEDIS Research Cluster, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium.
| | - Srinath Govindarajan
- Department of Internal Medicine and Paediatrics, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB-Center for Inflammation Research, Technologiepark 71, 9052, Zwijnaarde, Ghent, Belgium
| | - Sivaprakash Rajasekharan
- Department of Paediatric Dentistry and Special Care, PAECOMEDIS Research Cluster, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium
| | - Heidi Declercq
- Tissue Engineering and Biomaterials Group, Department of Human Structure and Repair, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium.,Tissue Engineering Lab, Department of Development and Regeneration, KU Leuven, 8500, Kortrijk, Belgium
| | - Dirk Elewaut
- Department of Internal Medicine and Paediatrics, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB-Center for Inflammation Research, Technologiepark 71, 9052, Zwijnaarde, Ghent, Belgium
| | - Peter De Coster
- Department of Reconstructive Dentistry and Oral Biology, Dental School, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium
| | - Luc Martens
- Department of Paediatric Dentistry and Special Care, PAECOMEDIS Research Cluster, Ghent University, Ghent University Hospital, 9000, Ghent, Belgium
| | - Luc Leybaert
- Department of Basic And Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
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10
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Bao MN, Zhang LJ, Tang B, Fu DD, Li J, Du L, Hou YN, Zhang ZL, Tang HW, Pang DW. Influenza A Viruses Enter Host Cells via Extracellular Ca2+ Influx-Involved Clathrin-Mediated Endocytosis. ACS APPLIED BIO MATERIALS 2021; 4:2044-2051. [DOI: 10.1021/acsabm.0c00968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Meng-Ni Bao
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Li-Juan Zhang
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Bo Tang
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Dan-Dan Fu
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Jing Li
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Lei Du
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Yi-Ning Hou
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Zhi-Ling Zhang
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Hong-Wu Tang
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
| | - Dai-Wen Pang
- College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P. R. China
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, and College of Chemistry, Nankai University, Tianjin 300071, P. R. China
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11
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Goldring AC, Beurg M, Fettiplace R. The contribution of TMC1 to adaptation of mechanoelectrical transduction channels in cochlear outer hair cells. J Physiol 2019; 597:5949-5961. [PMID: 31633194 PMCID: PMC6910908 DOI: 10.1113/jp278799] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/17/2019] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS Hair cell mechanoelectrical transducer channels are opened by deflections of the hair bundle about a resting position set by incompletely understood adaptation mechanisms. We used three characteristics to define adaptation in hair cell mutants of transmembrane channel-like proteins, TMC1 and TMC2, which are considered to be channel constituents. The results obtained demonstrate that the three characteristics are not equivalent, and raise doubts about simple models in which intracellular Ca2+ regulates adaptation. Adaptation is faster and more effective in TMC1-containing than in TMC2-containing transducer channels. This result ties adaptation to the channel complex, and suggests that TMC1 is a better isoform for use in cochlear hair cells. We describe a TMC1 point mutation, D569N, that reduces the resting open probability and Ca2+ permeability of the transducer channels, comprising properties that may contribute to the deafness phenotype. ABSTRACT Recordings of mechanoelectrical transducer (MET) currents in cochlear hair cells were made in mice with mutations of transmembrane channel-like (TMC) protein to examine the effects on fast transducer adaptation. Adaptation was faster and more complete in Tmc2-/- than in Tmc1-/- , although this disparity was not explained by differences in Ca2+ permeability or Ca2+ influx between the two isoforms, with TMC2 having the larger permeability. We made a mouse mutation, Tmc1 p.D569N, homologous to a human DFNA36 deafness mutation, which also had MET channels with lower Ca2+ -permeability but showed better fast adaptation than wild-type Tmc1+/+ channels. Consistent with the more effective adaptation in Tmc1 p.D569N, the resting probability of MET channel opening was smaller. The three TMC variants studied have comparable single-channel conductances, although the lack of correlation between channel Ca2+ permeability and adaptation opposes the hypothesis that adaptation is controlled simply by Ca2+ influx through the channels. During the first postnatal week of mouse development, the MET currents amplitude grew, and transducer adaptation became faster and more effective. We attribute changes in adaptation partly to a developmental switch from TMC2- to TMC1- containing channels and partly to an increase in channel expression. More complete and faster adaptation, coupled with larger MET currents, may account for the sole use of TMC1 in the adult cochlear hair cells.
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Affiliation(s)
- Adam C Goldring
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Maryline Beurg
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Robert Fettiplace
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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12
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Luo Q, Wei G, Wu X, Tang K, Xu M, Wu Y, Liu Y, Li X, Sun Z, Ju W, Qi K, Chen C, Yan Z, Cheng H, Zhu F, Li Z, Zeng L, Xu K, Qiao J. Platycodin D inhibits platelet function and thrombus formation through inducing internalization of platelet glycoprotein receptors. J Transl Med 2018; 16:311. [PMID: 30442147 PMCID: PMC6238268 DOI: 10.1186/s12967-018-1688-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/09/2018] [Indexed: 01/25/2023] Open
Abstract
Background Platycodin D (PD) is one of the major bioactive components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties, such as antiviral, anti-inflammatory, and anti-cancer activities. However, whether it affects platelet function remains unclear. This study aims to evaluate the role of PD in platelet function and thrombus formation. Methods Platelets were treated with PD followed by measuring platelet aggregation, activation, spreading, clot retraction, expression of glycoprotein receptors. Moreover, mice platelets were treated with PD and infused into wild-type mice for analysis of in vivo hemostasis and arterial thrombosis. Results Platycodin D treatment significantly inhibited platelet aggregation in response to collagen, ADP, arachidonic acid and epinephrine, reduced platelet P-selectin expression, integrin αIIbβ3 activation, spreading on fibrinogen as well as clot retraction, accompanied with decreased phosphorylation of Syk and PLCγ2 in collagen-related peptide or thrombin-stimulated platelets. Moreover, PD-treated mice platelets presented significantly impaired in vivo hemostasis and arterial thrombus formation. Interestingly, PD induced internalization of glycoprotein receptors αIIbβ3, GPIbα and GPVI. However, GM6001, cytochalasin D, BAPTA-AM and wortmannin did not prevent PD-induced internalization of receptors. Conclusions Our study demonstrates that PD inhibits platelet aggregation, activation and impairs hemostasis and arterial thrombosis, suggesting it might be a potent anti-thrombotic drug.
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Affiliation(s)
- Qi Luo
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Guangyu Wei
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Xiaoqing Wu
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Kai Tang
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Mengdi Xu
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China.,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China.,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China
| | - Yulu Wu
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Yun Liu
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Xiaoqian Li
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Zengtian Sun
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China
| | - Wen Ju
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China.,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China.,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China
| | - Kunming Qi
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China
| | - Chong Chen
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China.,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China.,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China
| | - Zhiling Yan
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China
| | - Hai Cheng
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China
| | - Feng Zhu
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China
| | - Zhenyu Li
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China.,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China.,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China
| | - Lingyu Zeng
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China.,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China
| | - Kailin Xu
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China. .,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China. .,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China.
| | - Jianlin Qiao
- Blood Diseases Institute, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, China. .,Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Rd, Quanshan District, Xuzhou, 221002, China. .,Key Laboratory of Bone Marrow Stem Cell, Xuzhou, Jiangsu, China.
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13
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Bootman MD, Allman S, Rietdorf K, Bultynck G. Deleterious effects of calcium indicators within cells; an inconvenient truth. Cell Calcium 2018; 73:82-87. [DOI: 10.1016/j.ceca.2018.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 01/20/2023]
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14
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De Vriese K, Costa A, Beeckman T, Vanneste S. Pharmacological Strategies for Manipulating Plant Ca 2+ Signalling. Int J Mol Sci 2018; 19:E1506. [PMID: 29783646 PMCID: PMC5983822 DOI: 10.3390/ijms19051506] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 11/20/2022] Open
Abstract
Calcium is one of the most pleiotropic second messengers in all living organisms. However, signalling specificity is encoded via spatio-temporally regulated signatures that act with surgical precision to elicit highly specific cellular responses. How this is brought about remains a big challenge in the plant field, in part due to a lack of specific tools to manipulate/interrogate the plant Ca2+ toolkit. In many cases, researchers resort to tools that were optimized in animal cells. However, the obviously large evolutionary distance between plants and animals implies that there is a good chance observed effects may not be specific to the intended plant target. Here, we provide an overview of pharmacological strategies that are commonly used to activate or inhibit plant Ca2+ signalling. We focus on highlighting modes of action where possible, and warn for potential pitfalls. Together, this review aims at guiding plant researchers through the Ca2+ pharmacology swamp.
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Affiliation(s)
- Kjell De Vriese
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Ghent, Belgium.
- VIB Center for Plant Systems Biology, VIB, Technologiepark 927, 9052 Ghent, Belgium.
| | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milan, Italy.
- Instititute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy.
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Ghent, Belgium.
- VIB Center for Plant Systems Biology, VIB, Technologiepark 927, 9052 Ghent, Belgium.
| | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Ghent, Belgium.
- VIB Center for Plant Systems Biology, VIB, Technologiepark 927, 9052 Ghent, Belgium.
- Lab of Plant Growth Analysis, Ghent University Global Campus, Songdomunhwa-Ro, 119, Yeonsu-gu, Incheon 21985, Korea.
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15
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Babona-Pilipos R, Liu N, Pritchard-Oh A, Mok A, Badawi D, Popovic MR, Morshead CM. Calcium influx differentially regulates migration velocity and directedness in response to electric field application. Exp Cell Res 2018; 368:202-214. [PMID: 29729231 DOI: 10.1016/j.yexcr.2018.04.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/25/2018] [Accepted: 04/28/2018] [Indexed: 11/15/2022]
Abstract
Neural precursor cells (NPCs) respond to externally applied direct current electrical fields (DCEFs) by undergoing rapid and directed migration toward the cathode in a process known as galvanotaxis. It is unknown if the underlying mechanisms of galvanotactic migration is common to non-electrosensitive cells and if so, how NPCs and other galvanotactic cells sense and transduce electrical fields into cellular motility. In this study, we show that distinct aspects of NPC galvanotactic migration: motility (quantified through |velocity|) and directedness, are differentially regulated by calcium. We use low-Ca2+ culture conditions; an intracellular Ca2+ chelator; and voltage gated calcium channel (VGCC) inhibitors to specific channels expressed on NPCs, to demonstrate the role of Ca2+ influx in DCEF-induced NPC migration. Consistent with existing literature, we show Ca2+ is involved in F-actin polymerization that lengthens NPC membrane protrusions necessary for cellular motility. However, inhibiting Ca2+ results in reduced velocity but has no effect on DCEF-induced directedness. This dissociation between velocity and directedness reveal that these migration parameters can be independently regulated, thus suggesting a parallel process of sensing DCEFs by NPCs.
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Affiliation(s)
- R Babona-Pilipos
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada; Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - N Liu
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - A Pritchard-Oh
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - A Mok
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - D Badawi
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - M R Popovic
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - C M Morshead
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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16
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Phengchat R, Takata H, Uchiyama S, Fukui K. Calcium depletion destabilises kinetochore fibres by the removal of CENP-F from the kinetochore. Sci Rep 2017; 7:7335. [PMID: 28779172 PMCID: PMC5544769 DOI: 10.1038/s41598-017-07777-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 07/03/2017] [Indexed: 12/12/2022] Open
Abstract
The attachment of spindle fibres to the kinetochore is an important process that ensures successful completion of the cell division. The Ca2+ concentration increases during the mitotic phase and contributes microtubule stability. However, its role in the spindle organisation in mitotic cells remains controversial. Here, we investigated the role of Ca2+ on kinetochore fibres in living cells. We found that depletion of Ca2+ during mitosis reduced kinetochore fibre stability. Reduction of kinetochore fibre stability was not due to direct inhibition of microtubule polymerisation by Ca2+-depletion but due to elimination of one dynamic component of kinetochore, CENP-F from the kinetochore. This compromised the attachment of kinetochore fibres to the kinetochore which possibly causes mitotic defects induced by the depletion of Ca2+.
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Affiliation(s)
- Rinyaporn Phengchat
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, 565-0871, Osaka, Japan
| | - Hideaki Takata
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, 565-0871, Osaka, Japan. .,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, 563-8577, Osaka, Japan.
| | - Susumu Uchiyama
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, 565-0871, Osaka, Japan
| | - Kiichi Fukui
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, 565-0871, Osaka, Japan. .,Chromosome Engineering Research Centre, Tottori University, 86 Nishimachi, Yonago, 683-0826, Tottori, Japan.
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17
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Próchnicki T, Mangan MS, Latz E. Recent insights into the molecular mechanisms of the NLRP3 inflammasome activation. F1000Res 2016; 5. [PMID: 27508077 PMCID: PMC4963208 DOI: 10.12688/f1000research.8614.1] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 12/26/2022] Open
Abstract
Inflammasomes are high-molecular-weight protein complexes that are formed in the cytosolic compartment in response to danger- or pathogen-associated molecular patterns. These complexes enable activation of an inflammatory protease caspase-1, leading to a cell death process called pyroptosis and to proteolytic cleavage and release of pro-inflammatory cytokines interleukin (IL)-1β and IL-18. Along with caspase-1, inflammasome components include an adaptor protein, ASC, and a sensor protein, which triggers the inflammasome assembly in response to a danger signal. The inflammasome sensor proteins are pattern recognition receptors belonging either to the NOD-like receptor (NLR) or to the AIM2-like receptor family. While the molecular agonists that induce inflammasome formation by AIM2 and by several other NLRs have been identified, it is not well understood how the NLR family member NLRP3 is activated. Given that NLRP3 activation is relevant to a range of human pathological conditions, significant attempts are being made to elucidate the molecular mechanism of this process. In this review, we summarize the current knowledge on the molecular events that lead to activation of the NLRP3 inflammasome in response to a range of K (+) efflux-inducing danger signals. We also comment on the reported involvement of cytosolic Ca (2+) fluxes on NLRP3 activation. We outline the recent advances in research on the physiological and pharmacological mechanisms of regulation of NLRP3 responses, and we point to several open questions regarding the current model of NLRP3 activation.
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Affiliation(s)
- Tomasz Próchnicki
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany
| | - Matthew S Mangan
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany; Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA; German Center for Neurodegenerative Diseases, Bonn, Germany; Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
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18
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Oyama K, Arai T, Isaka A, Sekiguchi T, Itoh H, Seto Y, Miyazaki M, Itabashi T, Ohki T, Suzuki M, Ishiwata S. Directional bleb formation in spherical cells under temperature gradient. Biophys J 2016. [PMID: 26200871 DOI: 10.1016/j.bpj.2015.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Living cells sense absolute temperature and temporal changes in temperature using biological thermosensors such as ion channels. Here, we reveal, to our knowledge, a novel mechanism of sensing spatial temperature gradients within single cells. Spherical mitotic cells form directional membrane extensions (polar blebs) under sharp temperature gradients (≥∼0.065°C μm(-1); 1.3°C temperature difference within a cell), which are created by local heating with a focused 1455-nm laser beam under an optical microscope. On the other hand, multiple nondirectional blebs are formed under gradual temperature gradients or uniform heating. During heating, the distribution of actomyosin complexes becomes inhomogeneous due to a break in the symmetry of its contractile force, highlighting the role of the actomyosin complex as a sensor of local temperature gradients.
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Affiliation(s)
- Kotaro Oyama
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
| | - Tomomi Arai
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Akira Isaka
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Taku Sekiguchi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hideki Itoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; Institute of Medical Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore, Singapore
| | - Yusuke Seto
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Makito Miyazaki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takeshi Itabashi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takashi Ohki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
| | - Shin'ichi Ishiwata
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
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19
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Zalutskaya Z, Lapina T, Ermilova E. The Chlamydomonas reinhardtii alternative oxidase 1 is regulated by heat stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 97:229-34. [PMID: 26492131 DOI: 10.1016/j.plaphy.2015.10.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/03/2015] [Accepted: 10/09/2015] [Indexed: 05/27/2023]
Abstract
The alternative oxidase (AOX) is a non-energy conserving terminal oxidase that has emerged as an important mitochondrial component of the cell stress responses. Although the most studied abiotic condition in relation to Chlamydomonas reinhardtii is high temperature, changes in AOX capacity of the alga were studied only under oxidative stress and cold. To examine whether elevated temperatures affected AOX1 expression, we applied quantitative real-time PCR and pharmaceutical approaches. In this work, we demonstrated a sharp increase in AOX1 transcript and protein abundance under heat stress. Furthermore, C. reinhardtii cells displayed a large increase in alternative respiration in response to high temperature. Feeding with the protein kinase inhibitor staurosporine strongly retarded the AOX1 transcription. Finally, the addition of the calcium chelator EGTA prevented heat-induced AOX1 expression. Together, our results imply that heat-inducible Ca(2+) influx and protein kinase(s) may mediate AOX1 expression at elevated temperatures. Characterization of heat-induced AOX1 regulation in the green alga C. reinhardtii provides a framework for a more complete understanding of the function of this conserved protein.
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Affiliation(s)
- Zhanneta Zalutskaya
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Tatiana Lapina
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Elena Ermilova
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia.
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20
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Oyama K, Zeeb V, Kawamura Y, Arai T, Gotoh M, Itoh H, Itabashi T, Suzuki M, Ishiwata S. Triggering of high-speed neurite outgrowth using an optical microheater. Sci Rep 2015; 5:16611. [PMID: 26568288 PMCID: PMC4645119 DOI: 10.1038/srep16611] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 10/16/2015] [Indexed: 12/12/2022] Open
Abstract
Optical microheating is a powerful non-invasive method for manipulating biological functions such as gene expression, muscle contraction, and cell excitation. Here, we demonstrate its potential usage for regulating neurite outgrowth. We found that optical microheating with a water-absorbable 1,455-nm laser beam triggers directional and explosive neurite outgrowth and branching in rat hippocampal neurons. The focused laser beam under a microscope rapidly increases the local temperature from 36 °C to 41 °C (stabilized within 2 s), resulting in the elongation of neurites by more than 10 μm within 1 min. This high-speed, persistent elongation of neurites was suppressed by inhibitors of both microtubule and actin polymerization, indicating that the thermosensitive dynamics of these cytoskeletons play crucial roles in this heat-induced neurite outgrowth. Furthermore, we showed that microheating induced the regrowth of injured neurites and the interconnection of neurites. These results demonstrate the efficacy of optical microheating methods for the construction of arbitrary neural networks.
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Affiliation(s)
- Kotaro Oyama
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Vadim Zeeb
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142292, Russia
| | - Yuki Kawamura
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Tomomi Arai
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Mizuho Gotoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Hideki Itoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore
| | - Takeshi Itabashi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore.,Organization for University Research Initiatives, Waseda University, #304, Block 120-4, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041 Japan
| | - Shin'ichi Ishiwata
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore.,Organization for University Research Initiatives, Waseda University, #304, Block 120-4, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041 Japan
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21
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Schroda M, Hemme D, Mühlhaus T. The Chlamydomonas heat stress response. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:466-480. [PMID: 25754362 DOI: 10.1111/tpj.12816] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/25/2015] [Accepted: 02/26/2015] [Indexed: 05/18/2023]
Abstract
Heat waves occurring at increased frequency as a consequence of global warming jeopardize crop yield safety. One way to encounter this problem is to genetically engineer crop plants toward increased thermotolerance. To identify entry points for genetic engineering, a thorough understanding of how plant cells perceive heat stress and respond to it is required. Using the unicellular green alga Chlamydomonas reinhardtii as a model system to study the fundamental mechanisms of the plant heat stress response has several advantages. Most prominent among them is the suitability of Chlamydomonas for studying stress responses system-wide and in a time-resolved manner under controlled conditions. Here we review current knowledge on how heat is sensed and signaled to trigger temporally and functionally grouped sub-responses termed response elements to prevent damage and to maintain cellular homeostasis in plant cells.
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Affiliation(s)
- Michael Schroda
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
| | - Dorothea Hemme
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
| | - Timo Mühlhaus
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
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22
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Schmollinger S, Schulz-Raffelt M, Strenkert D, Veyel D, Vallon O, Schroda M. Dissecting the heat stress response in Chlamydomonas by pharmaceutical and RNAi approaches reveals conserved and novel aspects. MOLECULAR PLANT 2013; 6:1795-1813. [PMID: 23713078 DOI: 10.1093/mp/sst086] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
To study how conserved fundamental concepts of the heat stress response (HSR) are in photosynthetic eukaryotes, we applied pharmaceutical and antisense/amiRNA approaches to the unicellular green alga Chlamydomonas reinhardtii. The Chlamydomonas HSR appears to be triggered by the accumulation of unfolded proteins, as it was induced at ambient temperatures by feeding cells with the arginine analog canavanine. The protein kinase inhibitor staurosporine strongly retarded the HSR, demonstrating the importance of phosphorylation during activation of the HSR also in Chlamydomonas. While the removal of extracellular calcium by the application of EGTA and BAPTA inhibited the HSR in moss and higher plants, only the addition of BAPTA, but not of EGTA, retarded the HSR and impaired thermotolerance in Chlamydomonas. The addition of cycloheximide, an inhibitor of cytosolic protein synthesis, abolished the attenuation of the HSR, indicating that protein synthesis is necessary to restore proteostasis. HSP90 inhibitors induced a stress response when added at ambient conditions and retarded attenuation of the HSR at elevated temperatures. In addition, we detected a direct physical interaction between cytosolic HSP90A/HSP70A and heat shock factor 1, but surprisingly this interaction persisted after the onset of stress. Finally, the expression of antisense constructs targeting chloroplast HSP70B resulted in a delay of the cell's entire HSR, thus suggesting the existence of a retrograde stress signaling cascade that is desensitized in HSP70B-antisense strains.
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Affiliation(s)
- Stefan Schmollinger
- Molekulare Biotechnologie und Systembiologie, TU Kaiserslautern, Paul-Ehrlich-Str. 23, D-67663 Kaiserslautern, Germany
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23
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Kamiński MM, Röth D, Krammer PH, Gülow K. Mitochondria as oxidative signaling organelles in T-cell activation: physiological role and pathological implications. Arch Immunol Ther Exp (Warsz) 2013; 61:367-84. [PMID: 23749029 DOI: 10.1007/s00005-013-0235-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/13/2013] [Indexed: 12/22/2022]
Abstract
Early scientific reports limited the cell biological role of reactive oxygen species (ROS) to the cause of pathological damage. However, extensive research performed over the last decade led to a wide recognition of intracellular oxidative/redox signaling as a crucial mechanism of homeostatic regulation. Amongst different cellular processes known to be influenced by redox signaling, T-cell activation is one of the most established. Numerous studies reported an indispensible role for ROS as modulators of T-cell receptor-induced transcription. Nevertheless, mechanistic details regarding signaling pathways triggered by ROS are far from being delineated. The nature and interplay between enzymatic sources involved in the generation of "oxidative signals" are also a matter of ongoing research. In particular, active participation of the mitochondrial respiratory chain as ROS producer constitutes an intriguing issue with various implications for bioenergetics of activated T cells as well as for T-cell-mediated pathologies. The aim of the current review is to address these interesting concepts.
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Affiliation(s)
- Marcin M Kamiński
- Tumour Immunology Program, Division of Immunogenetics (D030), German Cancer Research Center (DKFZ), Heidelberg, Germany,
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24
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Thomsen ARB, Worm J, Jacobsen SE, Stahlhut M, Latta M, Bräuner-Osborne H. Strontium is a biased agonist of the calcium-sensing receptor in rat medullary thyroid carcinoma 6-23 cells. J Pharmacol Exp Ther 2012; 343:638-49. [PMID: 22942242 PMCID: PMC11047797 DOI: 10.1124/jpet.112.197210] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/30/2012] [Indexed: 09/23/2023] Open
Abstract
The calcium-sensing receptor (CaSR)-specific allosteric modulator cinacalcet has revolutionized the treatment of secondary hyperparathyroidism in patients with chronic kidney disease. However, its application is limited to patients with end-stage renal disease because of hypocalcemic side effects presumably caused by CaSR-mediated calcitonin secretion from thyroid parafollicular C-cells. These hypocalcemic side effects might be dampened by compounds that bias the signaling of CaSR, causing similar therapeutic effects as cinacalcet without stimulating calcitonin secretion. Because biased signaling of CaSR is poorly understood, the objective of the present study was to investigate biased signaling of CaSR by using rat medullary thyroid carcinoma 6-23 cells as a model of thyroid parafollicular C-cells. By doing concentration-response experiments we focused on the ability of two well known CaSR agonists, calcium and strontium, to activate six different signaling entities: G(q/11) signaling, G(i/o) signaling, G(s) signaling, extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling, intracellular calcium ([Ca(2+)](i)) mobilization, and calcitonin secretion. The experiments showed that strontium biases CaSR signaling toward ERK1/2 signaling and possibly another pathway independent of G(q/11) signaling and [Ca(2+)](i) mobilization. It is noteworthy that the potency of strontium-stimulated calcitonin secretion was elevated compared with calcium. Combining these results with experiments investigating signaling pathway components involved in calcitonin secretion, we found that the enhanced potency of strontium-mediated calcitonin secretion was caused by a different signaling pattern than that produced by calcium. Together, our results suggest that calcitonin secretion can be affected by CaSR-stimulated signaling bias, which may be used to develop novel drugs for the treatment of secondary hyperparathyroidism.
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Affiliation(s)
- Alex Rojas Bie Thomsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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25
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Figueiredo JF, Barhoumi R, Raffatellu M, Lawhon SD, Rousseau B, Burghardt RC, Tsolis RM, Bäumler AJ, Adams LG. Salmonella enterica serovar Typhimurium-induced internalization and IL-8 expression in HeLa cells does not have a direct relationship with intracellular Ca(2+) levels. Microbes Infect 2009; 11:850-8. [PMID: 19450704 DOI: 10.1016/j.micinf.2009.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 05/02/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
Abstract
The invasion-associated type III secretion system (T3SS-1) of S. Typhimurium is required to initiate and sustain an acute inflammatory response in the intestine. We investigated the relationship of S. Typhimurium T3SS-1-induced IL-8 expression and invasion with intracellular Ca(2+) mobilization in HeLa cells. Compared to the sipAsopABDE2 mutant, strains carrying a mutation in sipA, or mutations in sopABDE2 induced higher levels of IL-8 and greater bacterial internalization despite the fact that these mutants elicited similarly low intracellular concentrations of Ca(2+). Likewise, complemented sipAsopABDE2 mutant with sopE2 did not affect intracellular Ca(2+) concentrations or IL-8 expression, but significantly increased bacterial internalization. Treating HeLa cells with the calcium chelator BAPTA-AM or with D-BAPTA-AM, a derivative with greatly reduced Ca(2+) chelating activity, yielded strong evidence that BAPTA-AM does not affect invasion and inhibits IL-8 secretion by a calcium-dependent mechanism. These findings suggest that, although wild-type S. Typhimurium-induced IL-8 expression and bacterial internalization in HeLa cells coincides with increased cytosolic Ca(2+), the differing levels of IL-8 and invasion induced by strains carrying different effector proteins are unrelated to levels of intracellular Ca(2+).
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Affiliation(s)
- Josely F Figueiredo
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
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26
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Furuta A, Tanaka M, Omata W, Nagasawa M, Kojima I, Shibata H. Microtubule disruption with BAPTA and dimethyl BAPTA by a calcium chelation-independent mechanism in 3T3-L1 adipocytes. Endocr J 2009; 56:235-43. [PMID: 19023157 DOI: 10.1507/endocrj.k08e-321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
While the physiological role for calcium in the insulin action on glucose transport has been disputed, it was reassessed in a recent study by using a calcum chelator, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, tetra(acetoxymethyl) ester (BAPTA-AM). Although BAPTA has been widely used to study the role for calcium in a variety of cell functions, it has also been suggested to have properties unrelated to the calcium chelating activity. Here, we investigated the effects of BAPTA and dimethyl BAPTA on the cytoskeletons in 3T3-L1 adipocytes. Both calcium chelators were successfully loaded in 3T3-L1 adipocytes and inhibited endothelin-1-induced cytosolic calcium elevation. Confocal fluorescence microscopy revealed that BAPTA and dimethyl BAPTA caused profound depolymerization of the microtubules without affecting the cortical actin filaments in 3T3-L1 adipocytes. Biochemical quantification also showed that BAPTA and dimethyl BAPTA significantly decreased the amount of polymerized tubulin but had little effect on filamentous actin. Consistent with these results, GLUT4-positive perinuclear compartments were dispersed throughout the cytoplasm in BAPTA- or dimethyl BAPTA-loaded adipocytes. Intriguingly, these calcium chelators did not disrupt the microtubules in undifferentiated preadipocytes. The microtubule-depolymerizing property of BAPTA and dimethyl BAPTA is unrelated to calcium chelation, since the microtubules were resistant to depletion of cytosolic calcium by using a calcium ionophore A23187. Insulin-stimulated glucose transport was not affected by cytosolic calcium depletion with A23187, but significantly inhibited with BAPTA and dimethyl BAPTA to the extent similar to that with nocodazole. BAPTA and its derivatives should be used with caution in studies of cytoskeleton-related cell functions.
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Affiliation(s)
- Ai Furuta
- Department of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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27
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Suzuki H, Saito Y. Cumulus cells affect distribution and function of the cytoskeleton and organelles in porcine oocytes. Reprod Med Biol 2006; 5:183-194. [PMID: 29699248 DOI: 10.1111/j.1447-0578.2006.00140.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Mammalian oocytes grow and undergo meiosis within ovarian follicles. Oocytes are arrested at the first meiotic prophase, being controlled or influenced by follicular somatic cells. Under the influence of gonadotropins, immature oocytes resume meiosis. During meiotic progression, some cytoplasmic changes occur, so-called cytoplasmic maturation. However, porcine follicular oocytes vary greatly in developmental competence. The present review summarizes recent studies highlighting the importance of cumulus cells in maintaining the developmental ability and in reorganizing the cytoskeleton and organelles of porcine oocytes. Factors affecting wide variation of the nuclear and cytoplasmic maturation observed in the porcine oocytes are discussed. (Reprod Med Biol 2006; 5: 183-194).
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Affiliation(s)
- Hiroyuki Suzuki
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan
| | - Yosuke Saito
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan
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28
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Cortez M, Atayde V, Yoshida N. Host cell invasion mediated by Trypanosoma cruzi surface molecule gp82 is associated with F-actin disassembly and is inhibited by enteroinvasive Escherichia coli. Microbes Infect 2006; 8:1502-12. [PMID: 16697683 DOI: 10.1016/j.micinf.2006.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Revised: 12/13/2005] [Accepted: 01/06/2006] [Indexed: 01/21/2023]
Abstract
The target cell F-actin disassembly, induced by a Ca2+-signaling Trypanosoma cruzi factor of unknown molecular identity, has been reported to promote parasite invasion. We investigated whether the metacyclic trypomastigote stage-specific surface molecule gp82, a Ca2+-signal-inducing molecule implicated in host cell invasion, displayed the ability to induce actin cytoskeleton disruption, using a recombinant protein (J18) containing the full-length gp82 sequence fused to GST. J18, but not GST, induced F-actin disassembly in HeLa cells, significantly reducing the number as well as the length of stress fibers. The number of cells with typical stress fibers scored approximately 70% in untreated and GST-treated cells, as opposed to approximately 30% in J18-treated samples, which also showed decreased F-actin content. J18, but not GST, inhibited approximately 6-fold the HeLa cell entry of enteroinvasive Escherichia coli (EIEC), which depends on actin cytoskeleton. Not only were fewer cells infected with bacteria in the presence of J18, there were also fewer bacteria per cell. The inhibitory activity of J18 was Ca2+ dependent. In co-infection experiments, preincubation of HeLa cells with EIEC drastically reduced gp82-dependent internalization of T. cruzi metacyclic forms. All these data, plus the finding that gp82-mediated penetration of metacyclic forms was associated with disrupted HeLa cell cytoskeletal architecture, indicate that gp82 promotes parasite invasion by disassembling the cortical actin cytoskeleton.
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Affiliation(s)
- Mauro Cortez
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu, 862, 6th andar, 04023-062 São Paulo, Brazil
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29
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Vassal E, Barette C, Fonrose X, Dupont R, Sans-Soleilhac E, Lafanechère L. Miniaturization and validation of a sensitive multiparametric cell-based assay for the concomitant detection of microtubule-destabilizing and microtubule-stabilizing agents. ACTA ACUST UNITED AC 2006; 11:377-89. [PMID: 16751334 DOI: 10.1177/1087057106286210] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The authors describe a cell-based assay for anti-microtubule compounds suitable for automation. This assay allows the identification, in a single screening campaign, of both microtubule-destabilizing and microtubule-stabilizing agents. Its rationale is based on the substrate properties of the tubulin-modifying enzymes involved in the tubulin tyrosination cycle. This cycle involves the removal of the C-terminal tyrosine of the tubulin alpha-subunit by an ill-defined tubulin carboxypeptidase and its readdition by tubulin tyrosine ligase. Because of the substrate properties of these enzymes, dynamic microtubules, sensitive to depolymerizing drugs, are composed of tyrosinated tubulin, whereas non-dynamic, stabilized microtubules are composed of detyrosinated tubulin. Thus depolymerization or stabilization of the microtubule network can easily be detected with double-immunofluorescence staining using antibodies specific to tyrosinated and detyrosinated tubulin. The authors have scaled this assay to the 96-well plate format and adapted its process for an automated handling, including a readout using a microplate reader. They describe the different steps of this adaptation. This assay was validated using known compounds. This new cell-based assay represents an alternative to both global cytotoxicity assays and in vitro tubulin assembly assays commonly used for the detection of microtubule poisons.
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Affiliation(s)
- Emilie Vassal
- Université Joseph Fourier, INSERM U366-CS/DRDC/CEA Grenoble, France
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30
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Fang Y, Li GG, Peng J. Optical biosensor provides insights for bradykinin B2receptor signaling in A431 cells. FEBS Lett 2005; 579:6365-74. [PMID: 16263113 DOI: 10.1016/j.febslet.2005.10.019] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 10/10/2005] [Accepted: 10/13/2005] [Indexed: 11/18/2022]
Abstract
The spatial and temporal targeting of proteins or protein assemblies to appropriate sites is crucial to regulate the specificity and efficiency of protein-protein interactions, thus dictating the timing and intensity of cell signaling and responses. The resultant dynamic mass redistribution could be manifested by label free optical biosensor, and lead to a novel and functional optical signature for studying cell signaling. Here we applied this technology, termed as mass redistribution cell assay technology (MRCAT), to study the signaling networks of bradykinin B(2) receptor in A431 cells. Using MRCAT, the spatial and temporal relocation of proteins and protein assemblies mediated by bradykinin was quantitatively monitored in microplate format and in live cells. The saturability to bradykinin, together with the specific and dose-dependent inhibition by a B(2) specific antagonist HOE140, suggested that the optical signature is a direct result of B(2) receptor activation. The sensitivity of the optical signature to cholesterol depletion by methyl-beta-cyclodextrin argued that B(2) receptor signaling is dependent on the integrity of lipid rafts; disruption of these microdomains hinders the B(2) signaling. Modulations of several important intracellular targets with specific inhibitors suggested that B(2) receptor activation results in signaling via at least dual pathways - G(s)- and G(q)-mediated signaling. Remarkably, the two signaling pathways counter-regulate each other. Several critical downstream targets including protein kinase C, protein kinase A, and epidermal growth factor receptor had been identified to involve in B(2) signaling. The roles of endocytosis and cytoskeleton modulation in B(2) signaling were also demonstrated.
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Affiliation(s)
- Ye Fang
- Biochemical Technologies, Science and Technology Division, Corning Incorporated, Sullivan Park, Corning, NY 14831, USA.
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31
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Starai VJ, Thorngren N, Fratti RA, Wickner W. Ion regulation of homotypic vacuole fusion in Saccharomyces cerevisiae. J Biol Chem 2005; 280:16754-62. [PMID: 15737991 DOI: 10.1074/jbc.m500421200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biological membrane fusion employs divalent cations as protein cofactors or as signaling ligands. For example, Mg2+ is a cofactor for the N-ethylmaleimide-sensitive factor (NSF) ATPase, and the Ca2+ signal from neuronal membrane depolarization is required for synaptotagmin activation. Divalent cations also regulate liposome fusion, but the role of such ion interactions with lipid bilayers in Rab- and soluble NSF attachment protein receptor (SNARE)-dependent biological membrane fusion is less clear. Yeast vacuole fusion requires Mg2+ for Sec18p ATPase activity, and vacuole docking triggers an efflux of luminal Ca2+. We now report distinct reaction conditions where divalent or monovalent ions interchangeably regulate Rab- and SNARE-dependent vacuole fusion. In reactions with 5 mm Mg2+, other free divalent ions are not needed. Reactions containing low Mg2+ concentrations are strongly inhibited by the rapid Ca2+ chelator BAPTA. However, addition of the soluble SNARE Vam7p relieves BAPTA inhibition as effectively as Ca2+ or Mg2+, suggesting that Ca2+ does not perform a unique signaling function. When the need for Mg2+, ATP, and Sec18p for fusion is bypassed through the addition of Vam7p, vacuole fusion does not require any appreciable free divalent cations and can even be stimulated by their chelators. The similarity of these findings to those with liposomes, and the higher ion specificity of the regulation of proteins, suggests a working model in which ion interactions with bilayer lipids permit Rab- and SNARE-dependent membrane fusion.
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Affiliation(s)
- Vincent J Starai
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755-3844, USA
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