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Lu CY, Wu JZ, Yao HHY, Liu RJY, Li L, Pluthero FG, Freeman SA, Kahr WHA. Acidification of α-granules in megakaryocytes by vacuolar-type adenosine triphosphatase is essential for organelle biogenesis. J Thromb Haemost 2024; 22:2294-2305. [PMID: 38718926 DOI: 10.1016/j.jtha.2024.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 06/10/2024]
Abstract
BACKGROUND Platelets coordinate blood coagulation at sites of vascular injury and play fundamental roles in a wide variety of (patho)physiological processes. Key to many platelet functions is the transport and secretion of proteins packaged within α-granules, organelles produced by platelet precursor megakaryocytes. Prominent among α-granule cargo are fibrinogen endocytosed from plasma and endogenously synthesized von Willebrand factor. These and other proteins are known to require acidic pH for stable packaging. Luminal acidity has been confirmed for mature α-granules isolated from platelets, but direct measurement of megakaryocyte granule acidity has not been reported. OBJECTIVES To determine the luminal pH of α-granules and their precursors in megakaryocytes and assess the requirement of vacuolar-type adenosine triphosphatase (V-ATPase) activity to establish and maintain the luminal acidity and integrity of these organelles. METHODS Cresyl violet staining was used to detect acidic granules in megakaryocytes. Endocytosis of fibrinogen tagged with the pH-sensitive fluorescent dye fluorescein isothiocyanate was used to load a subset of these organelles. Ratiometric fluorescence analysis was used to determine their luminal pH. RESULTS We show that most of the acidic granules detected in megakaryocytes appear to be α-granules/precursors, for which we established a median luminal pH of 5.2 (IQR, 5.0-5.5). Inhibition of megakaryocyte V-ATPase activity led to enlargement of cargo-containing compartments detected by fluorescence microscopy and electron microscopy. CONCLUSION These observations reveal that V-ATPase activity is required to establish and maintain a luminal acidic pH in megakaryocyte α-granules/precursors, confirming its importance for stable packaging of cargo proteins such as von Willebrand factor.
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Affiliation(s)
- Chien-Yi Lu
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jing Ze Wu
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Helen H Y Yao
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Richard J Y Liu
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Ling Li
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Fred G Pluthero
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Spencer A Freeman
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Walter H A Kahr
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Division of Haematology/Oncology, Department of Paediatrics, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada.
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2
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Berna-Erro A, Granados MP, Teruel-Montoya R, Ferrer-Marin F, Delgado E, Corbacho AJ, Fenández E, Vazquez-Godoy MT, Tapia JA, Redondo PC. SARAF overexpression impairs thrombin-induced Ca 2+ homeostasis in neonatal platelets. Br J Haematol 2024; 204:988-1004. [PMID: 38062782 DOI: 10.1111/bjh.19210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 03/14/2024]
Abstract
Neonatal platelets present a reduced response to the platelet agonist, thrombin (Thr), thus resulting in a deficient Thr-induced aggregation. These alterations are more pronounced in premature newborns. Here, our aim was to uncover the causes underneath the impaired Ca2+ homeostasis described in neonatal platelets. Both Ca2+ mobilization and Ca2+ influx in response to Thr are decreased in neonatal platelets compared to maternal and control woman platelets. In neonatal platelets, we observed impaired Ca2+ mobilization in response to the PAR-1 agonist (SFLLRN) or by blocking SERCA3 function with tert-butylhydroquinone. Regarding SOCE, the STIM1 regulatory protein, SARAF, was found overexpressed in neonatal platelets, promoting an increase in STIM1/SARAF interaction even under resting conditions. Additionally, higher interaction between SARAF and PDCD61/ALG2 was also observed, reducing SARAF ubiquitination and prolonging its half-life. These results were reproduced by overexpressing SARAF in MEG01 and DAMI cells. Finally, we also observed that pannexin 1 permeability is enhanced in response to Thr in control woman and maternal platelets, but not in neonatal platelets, hence, leading to the deregulation of the Ca2+ entry found in neonatal platelets. Summarizing, we show that in neonatal platelets both Ca2+ accumulation in the intracellular stores and Thr-evoked Ca2+ entry through either capacitative channels or non-selective channels are altered in neonatal platelets, contributing to deregulated Ca2+ homeostasis in neonatal platelets and leading to the altered aggregation observed in these subjects.
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Affiliation(s)
- Alejandro Berna-Erro
- Department of Physiology (PHYCELL Group), University of Extremadura, Caceres, Spain
| | - Maria P Granados
- Pharmacy Unit of Health Center, Extremadura County Health Service, Caceres, Spain
| | - Raul Teruel-Montoya
- Hemodonation County Center, University Hospital of Morales-Meseguer, IMIB-Arrixaca, CIBERER CB55, Murcia, Spain
| | - Francisca Ferrer-Marin
- Hemodonation County Center, University Hospital of Morales-Meseguer, IMIB-Arrixaca, CIBERER CB55, Murcia, Spain
| | - Elena Delgado
- Blood Donation Center, Extremadura County Health Service, Merida, Spain
| | | | | | | | - Jose A Tapia
- Department of Physiology (PHYCELL Group), University of Extremadura, Caceres, Spain
| | - Pedro Cosme Redondo
- Department of Physiology (PHYCELL Group), University of Extremadura, Caceres, Spain
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3
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Miller ZA, Mueller A, Kim T, Jolivert JF, Ma RZ, Muthuswami S, Park A, McMahon DB, Nead KT, Carey RM, Lee RJ. Lidocaine induces apoptosis in head and neck squamous cell carcinoma through activation of bitter taste receptor T2R14. Cell Rep 2023; 42:113437. [PMID: 37995679 PMCID: PMC10842818 DOI: 10.1016/j.celrep.2023.113437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 09/22/2023] [Accepted: 10/29/2023] [Indexed: 11/25/2023] Open
Abstract
Head and neck squamous cell carcinomas (HNSCCs) have high mortality and significant treatment-related morbidity. It is vital to discover effective, minimally invasive therapies that improve survival and quality of life. Bitter taste receptors (T2Rs) are expressed in HNSCCs, and T2R activation can induce apoptosis. Lidocaine is a local anesthetic that also activates bitter taste receptor 14 (T2R14). Lidocaine has some anti-cancer effects, but the mechanisms are unclear. Here, we find that lidocaine causes intracellular Ca2+ mobilization through activation of T2R14 in HNSCC cells. T2R14 activation with lidocaine depolarizes mitochondria, inhibits proliferation, and induces apoptosis. Concomitant with mitochondrial Ca2+ influx, ROS production causes T2R14-dependent accumulation of poly-ubiquitinated proteins, suggesting that proteasome inhibition contributes to T2R14-induced apoptosis. Lidocaine may have therapeutic potential in HNSCCs as a topical gel or intratumor injection. In addition, we find that HPV-associated (HPV+) HNSCCs are associated with increased TAS2R14 expression. Lidocaine treatment may benefit these patients, warranting future clinical studies.
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Affiliation(s)
- Zoey A Miller
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Pharmacology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Arielle Mueller
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - TaeBeom Kim
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jennifer F Jolivert
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ray Z Ma
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sahil Muthuswami
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - April Park
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Derek B McMahon
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Kevin T Nead
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ryan M Carey
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Robert J Lee
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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4
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Martucci LL, Cancela JM. Neurophysiological functions and pharmacological tools of acidic and non-acidic Ca2+ stores. Cell Calcium 2022; 104:102582. [DOI: 10.1016/j.ceca.2022.102582] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/07/2022] [Accepted: 03/23/2022] [Indexed: 02/08/2023]
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5
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Sage SO, Harper AGS. Calcium sequestration by human platelet acidic organelles is regulated by the actin cytoskeleton and autocrine 5-hydroxytryptamine. Cell Calcium 2021; 101:102522. [PMID: 34968774 DOI: 10.1016/j.ceca.2021.102522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/25/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022]
Abstract
Human platelets regulate agonist-evoked Ca2+ signalling through Ca2+ release from and sequestration into acidic organelles. Previous studies have pharmacologically characterised the presence of a Ca2+-H+ exchanger in these organelles. This exchanger appears to regulate a secondary plateau phase in agonist-evoked cytosolic Ca2+ signals in fura-2-loaded human platelets. Here we demonstrate that cytochalasin D treatment removes the secondary plateau in ADP-evoked Ca2+ signals elicited in the absence of external Ca2+. This effect was reversed by pretreatment with nigericin, a K+/H+ exchanger that short-circuits the Ca2+-H+ exchanger. Using Fluo-5N- or Lysosensor Green-loaded cells, cytochalasin D was found to enhance Ca2+ sequestration into acidic organelles by preventing their alkalinisation. Additional experiments demonstrated that ADP-evoked alkalinisation of acidic organelles and subsequent slowing of acidic organellar Ca2+ sequestration was mediated by autocrine 5-HT signalling. Enhancing this 5-HT signalling using fluoxetine overcame the inhibitory effect of cytochalasin D on ADP-evoked Ca2+ signals, indicating that cytochalasin D interferes with 5-HT autocrine signalling. The ability of Cytochalasin D to interfere with autocrine 5-HT signalling was downstream of the 5-HT2A receptor as secretion of [3H]-5-HT from ADP-stimulated human platelets was not reduced. These data provide the first evidence that the pH gradient across acidic organelles is dynamically regulated upon human platelet activation, and that this can play a significant role in controlling human platelet function by modulating Ca2+-H+ exchange and so [Ca2+]i.
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Affiliation(s)
- Stewart O Sage
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alan G S Harper
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; School of Medicine, David Wetherall Building, Keele University, Keele, Staffordshire, ST5 5BG United Kingdom.
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6
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Davis LC, Morgan AJ, Galione A. Acidic Ca 2+ stores and immune-cell function. Cell Calcium 2021; 101:102516. [PMID: 34922066 DOI: 10.1016/j.ceca.2021.102516] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 12/11/2022]
Abstract
Acidic organelles act as intracellular Ca2+ stores; they actively sequester Ca2+ in their lumina and release it to the cytosol upon activation of endo-lysosomal Ca2+ channels. Recent data suggest important roles of endo-lysosomal Ca2+ channels, the Two-Pore Channels (TPCs) and the TRPML channels (mucolipins), in different aspects of immune-cell function, particularly impacting membrane trafficking, vesicle fusion/fission and secretion. Remarkably, different channels on the same acidic vesicles can couple to different downstream physiology. Endo-lysosomal Ca2+ stores can act under different modalities, be they acting alone (via local Ca2+ nanodomains around TPCs/TRPMLs) or in conjunction with the ER Ca2+ store (to either promote or suppress global ER Ca2+ release). These different modalities impinge upon functions as broad as phagocytosis, cell-killing, anaphylaxis, immune memory, thrombostasis, and chemotaxis.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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Santra P, Amack JD. Loss of vacuolar-type H+-ATPase induces caspase-independent necrosis-like death of hair cells in zebrafish neuromasts. Dis Model Mech 2021; 14:dmm048997. [PMID: 34296747 PMCID: PMC8319552 DOI: 10.1242/dmm.048997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/15/2021] [Indexed: 01/24/2023] Open
Abstract
The vacuolar-type H+-ATPase (V-ATPase) is a multi-subunit proton pump that regulates cellular pH. V-ATPase activity modulates several cellular processes, but cell-type-specific functions remain poorly understood. Patients with mutations in specific V-ATPase subunits can develop sensorineural deafness, but the underlying mechanisms are unclear. Here, we show that V-ATPase mutations disrupt the formation of zebrafish neuromasts, which serve as a model to investigate hearing loss. V-ATPase mutant neuromasts are small and contain pyknotic nuclei that denote dying cells. Molecular markers and live imaging show that loss of V-ATPase induces mechanosensory hair cells in neuromasts, but not neighboring support cells, to undergo caspase-independent necrosis-like cell death. This is the first demonstration that loss of V-ATPase can lead to necrosis-like cell death in a specific cell type in vivo. Mechanistically, loss of V-ATPase reduces mitochondrial membrane potential in hair cells. Modulating the mitochondrial permeability transition pore, which regulates mitochondrial membrane potential, improves hair cell survival. These results have implications for understanding the causes of sensorineural deafness, and more broadly, reveal functions for V-ATPase in promoting survival of a specific cell type in vivo.
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Affiliation(s)
- Peu Santra
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Syracuse: Institute for Material and Living Systems, Syracuse, NY 13244, USA
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8
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Negri S, Faris P, Moccia F. Endolysosomal Ca 2+ signaling in cardiovascular health and disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 363:203-269. [PMID: 34392930 DOI: 10.1016/bs.ircmb.2021.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An increase in intracellular Ca2+ concentration ([Ca2+]i) regulates a plethora of functions in the cardiovascular (CV) system, including contraction in cardiomyocytes and vascular smooth muscle cells (VSMCs), and angiogenesis in vascular endothelial cells and endothelial colony forming cells. The sarco/endoplasmic reticulum (SR/ER) represents the largest endogenous Ca2+ store, which releases Ca2+ through ryanodine receptors (RyRs) and/or inositol-1,4,5-trisphosphate receptors (InsP3Rs) upon extracellular stimulation. The acidic vesicles of the endolysosomal (EL) compartment represent an additional endogenous Ca2+ store, which is targeted by several second messengers, including nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2], and may release intraluminal Ca2+ through multiple Ca2+ permeable channels, including two-pore channels 1 and 2 (TPC1-2) and Transient Receptor Potential Mucolipin 1 (TRPML1). Herein, we discuss the emerging, pathophysiological role of EL Ca2+ signaling in the CV system. We describe the role of cardiac TPCs in β-adrenoceptor stimulation, arrhythmia, hypertrophy, and ischemia-reperfusion injury. We then illustrate the role of EL Ca2+ signaling in VSMCs, where TPCs promote vasoconstriction and contribute to pulmonary artery hypertension and atherosclerosis, whereas TRPML1 sustains vasodilation and is also involved in atherosclerosis. Subsequently, we describe the mechanisms whereby endothelial TPCs promote vasodilation, contribute to neurovascular coupling in the brain and stimulate angiogenesis and vasculogenesis. Finally, we discuss about the possibility to target TPCs, which are likely to mediate CV cell infection by the Severe Acute Respiratory Disease-Coronavirus-2, with Food and Drug Administration-approved drugs to alleviate the detrimental effects of Coronavirus Disease-19 on the CV system.
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Affiliation(s)
- Sharon Negri
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Pawan Faris
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Francesco Moccia
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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9
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Vishalakshi GJ, Hemshekhar M, Sandesha VD, Prashanth KS, Jagadish S, Paul M, Kemparaju K, Girish KS. Bisphenol AF elevates procoagulant platelets by inducing necroptosis via RIPK1-inflammasome axis. Toxicology 2021; 454:152742. [PMID: 33662508 DOI: 10.1016/j.tox.2021.152742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/30/2021] [Accepted: 02/26/2021] [Indexed: 12/11/2022]
Abstract
Bisphenol AF, an analogue of Bisphenol A, is an important raw material used in the production of plastic and rubber substances like plastic bottles and containers, toys, and medical supplies. Increased contamination of air, water, dust, and food with BPA/BPAF, poses an enormous threat to humans, globally. BPAF/BPA are endocrine-disrupting chemicals that mimic estrogen hormone, thus increasing the risks of various metabolic and chronic disorders. Exposure of human blood cells to BPA/BPAF induces oxidative stress and genotoxicity. However, its effects on platelets, which play central roles in hemostasis and thrombosis, are not well-documented. In this study, we demonstrate that BPAF induces RIPK1-inflammasome axis-mediated necroptosis in platelets, increasing procoagulant platelet levels in vivo and in vitro. We also show that BPAF-induced rise in procoagulant platelets worsens pulmonary thromboembolism in vivo. The elevated procoagulant platelets are shown to increase platelet-neutrophil/monocyte aggregates that mediate pathogenesis of CVD, thrombosis, and chronic inflammatory diseases. Our results demonstrate the toxic effects of BPAF on platelets and how it propagates the clinical complications by elevating procoagulant platelet numbers. Altogether, our study sends a cautionary message against extensive use of BPAF in the plastic and rubber industries, resulting in frequent human exposure to it, thus endangering platelet functions.
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Affiliation(s)
- Gopalapura J Vishalakshi
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India
| | - Mahadevappa Hemshekhar
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India
| | | | - Kunthurumole S Prashanth
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India
| | - Swamy Jagadish
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India
| | - Manoj Paul
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India
| | - Kempaiah Kemparaju
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India.
| | - Kesturu S Girish
- Department of Studies in Biochemistry, University of Mysore, Manasagangotri, Mysuru, 570 006, India; Department of Studies and Research in Biochemistry, Tumkur University, Tumakuru, 572 103, India.
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10
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Zaman MF, Nenadic A, Radojičić A, Rosado A, Beh CT. Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex. Front Cell Dev Biol 2020; 8:675. [PMID: 32793605 PMCID: PMC7387695 DOI: 10.3389/fcell.2020.00675] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/03/2020] [Indexed: 12/31/2022] Open
Abstract
Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and species-specific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.
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Affiliation(s)
- Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ana Radojičić
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,The Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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11
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Feng M, Elaïb Z, Borgel D, Denis CV, Adam F, Bryckaert M, Rosa JP, Bobe R. NAADP/SERCA3-Dependent Ca 2+ Stores Pathway Specifically Controls Early Autocrine ADP Secretion Potentiating Platelet Activation. Circ Res 2020; 127:e166-e183. [PMID: 32588751 DOI: 10.1161/circresaha.119.316090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Ca2+ signaling is a key and ubiquitous actor of cell organization and its modulation controls many cellular responses. SERCAs (sarco-endoplasmic reticulum Ca2+-ATPases) pump Ca2+ into internal stores that play a major role in the cytosolic Ca2+ concentration rise upon cell activation. Platelets exhibit 2 types of SERCAs, SERCA2b and SERCA3 (SERCA3 deficient mice), which may exert specific roles, yet ill-defined. We have recently shown that Ca2+ mobilization from SERCA3-dependent stores was required for full platelet activation in weak stimulation conditions. OBJECTIVE To uncover the signaling mechanisms associated with Ca2+ mobilization from SERCA3-dependent stores leading to ADP secretion. METHODS AND RESULTS Using platelets from wild-type or Serca3-deficient mice, we demonstrated that an early (within 5-10 s following stimulation) secretion of ADP specifically dependent on SERCA3 stored Ca2+ is exclusively mobilized by nicotinic acid adenosine dinucleotide-phosphate (NAADP): both Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion are blocked by the NAADP receptor antagonist Ned-19, and reciprocally both are stimulated by permeant NAADP. In contrast, Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion were unaffected by inhibition of the production of IP3 (inositol-1,4,5-trisphosphate) by phospholipase-C and accordingly were not stimulated by permeant IP3. CONCLUSIONS Upon activation, an NAADP/SERCA3 Ca2+ mobilization pathway initiates an early ADP secretion, potentiating platelet activation, and a secondary wave of ADP secretion driven by both an IP3/SERCA2b-dependent Ca2+ stores pathway and the NAADP/SERCA3 pathway. This does not exclude that Ca2+ mobilized from SERCA3 stores may also enhance platelet global reactivity to agonists. Because of its modulating effect on platelet activation, this NAADP-SERCA3 pathway may be a relevant target for anti-thrombotic therapy. Graphic Abstract: A graphic abstract is available for this article.
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Affiliation(s)
- Miao Feng
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Ziane Elaïb
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Delphine Borgel
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Cécile V Denis
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Frédéric Adam
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Marijke Bryckaert
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Jean-Philippe Rosa
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
| | - Régis Bobe
- From the HITh, UMR_S1176, INSERM, Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France
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12
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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. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 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] [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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13
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Morgan AJ, Yuan Y, Patel S, Galione A. Does lysosomal rupture evoke Ca 2+ release? A question of pores and stores. Cell Calcium 2019; 86:102139. [PMID: 31881482 DOI: 10.1016/j.ceca.2019.102139] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 02/04/2023]
Abstract
Lysosomotropic agents have been used to permeabilize lysosomes and thereby implicate these organelles in diverse cellular processes. Since lysosomes are Ca2+ stores, this rupturing action, particularly that induced by GPN, has also been used to rapidly release Ca2+ from lysosomes. However, a recent study has questioned the mechanism of action of GPN and concluded that, acutely, it does not permeabilize lysosomes but releases Ca2+ directly from the ER instead. We therefore appraise these provocative findings in the context of the existing literature. We suggest that further work is required to unequivocally rule out lysosomes as contributors to GPN-evoked Ca2+ signals.
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Affiliation(s)
- Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom.
| | - Yu Yuan
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom
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14
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El Haouari M. Platelet Oxidative Stress and its Relationship with Cardiovascular Diseases in Type 2 Diabetes Mellitus Patients. Curr Med Chem 2019; 26:4145-4165. [PMID: 28982316 DOI: 10.2174/0929867324666171005114456] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 06/07/2017] [Accepted: 06/07/2017] [Indexed: 01/01/2023]
Abstract
Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases (CVD). Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2 -, H2O2 or OH-, further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism.
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Affiliation(s)
- Mohammed El Haouari
- Centre Regional des Metiers de l'Education et de la Formation de Taza (CRMEF - Taza), B.P: 1178 - Taza Gare, Morocco
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15
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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] [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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16
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Westman J, Grinstein S, Maxson ME. Revisiting the role of calcium in phagosome formation and maturation. J Leukoc Biol 2019; 106:837-851. [DOI: 10.1002/jlb.mr1118-444r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 12/19/2022] Open
Affiliation(s)
- Johannes Westman
- Program in Cell BiologyHospital for Sick Children Toronto Ontario Canada
| | - Sergio Grinstein
- Program in Cell BiologyHospital for Sick Children Toronto Ontario Canada
- Department of BiochemistryUniversity of Toronto Toronto Ontario Canada
- Keenan Research Centre of the Li Ka Shing Knowledge InstituteSt. Michael's Hospital Toronto Ontario Canada
| | - Michelle E. Maxson
- Program in Cell BiologyHospital for Sick Children Toronto Ontario Canada
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17
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Lopez E, Frischauf I, Jardin I, Derler I, Muik M, Cantonero C, Salido GM, Smani T, Rosado JA, Redondo PC. STIM1 phosphorylation at Y 316 modulates its interaction with SARAF and the activation of SOCE and ICRAC. J Cell Sci 2019; 132:jcs226019. [PMID: 30975919 DOI: 10.1242/jcs.226019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/08/2019] [Indexed: 01/24/2023] Open
Abstract
Stromal interaction molecule 1 (STIM1) is one of the key elements for the activation of store-operated Ca2+ entry (SOCE). Hence, identification of the relevant phosphorylatable STIM1 residues with a possible role in the regulation of STIM1 function and SOCE is of interest. By performing a computational analysis, we identified that the Y316 residue is susceptible to phosphorylation. Expression of the STIM1-Y316F mutant in HEK293, NG115-401L and MEG-01 cells resulted in a reduction in STIM1 tyrosine phosphorylation, SOCE and the Ca2+ release-activated Ca2+ current (ICRAC). STIM1-Orai1 colocalization was reduced in HEK293 cells transfected with YFP-STIM1-Y316F compared to in cells with wild-type (WT) YFP-tagged STIM1. Additionally, the Y316F mutation altered the pattern of interaction between STIM1 and SARAF under resting conditions and upon Ca2+ store depletion. Expression of the STIM1 Y316F mutant enhanced slow Ca2+-dependent inactivation (SCDI) as compared to STIM1 WT, an effect that was abolished by SARAF knockdown. Finally, in NG115-401L cells transfected with shRNA targeting SARAF, expression of STIM1 Y316F induced greater SOCE than STIM1 WT. Taken together, our results provide evidence supporting the idea that phosphorylation of STIM1 at Y316 plays a relevant functional role in the activation and modulation of SOCE.
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Affiliation(s)
- Esther Lopez
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - Irene Frischauf
- Molecular & Membrane Biophysics, Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Isaac Jardin
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - Isabella Derler
- Molecular & Membrane Biophysics, Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Martin Muik
- Molecular & Membrane Biophysics, Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Carlos Cantonero
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - Gines M Salido
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville (IBiS)/University of Seville/CIBERCV, 41013 Seville, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - Pedro C Redondo
- Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
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18
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Mandal D, Sinharoy S. A Toolbox for Nodule Development Studies in Chickpea: A Hairy-Root Transformation Protocol and an Efficient Laboratory Strain of Mesorhizobium sp. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:367-378. [PMID: 30398908 DOI: 10.1094/mpmi-09-18-0264-ta] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A Mesorhizobium sp. produces root nodules in chickpea. Chickpea and model legume Medicago truncatula are members of the inverted repeat-lacking clade (IRLC). The rhizobia, after internalization into the plant cell, are called bacteroids. Nodule-specific cysteine-rich peptides in IRLC legumes guide bacteroids to a terminally differentiated swollen (TDS) form. Bacteroids in chickpea are less TDS than those in Medicago spp. Nodule development in chickpea indicates recent evolutionary diversification and merits further study. A hairy-root transformation protocol and an efficient laboratory strain are prerequisites for performing any genetic study on nodulation. We have standardized a protocol for composite plant generation in chickpea with a transformation frequency above 50%, as shown by fluorescent markers. This protocol also works well in different ecotypes of chickpea. Localization of subcellular markers in these transformed roots is similar to the localization observed in transformed Medicago roots. When checked inside transformed nodules, peroxisomes were concentrated along the periphery of the nodules, while endoplasmic reticulum and Golgi bodies surrounded the symbiosomes. Different Mesorhizobium strains were evaluated for their ability to initiate nodule development and efficiency of nitrogen fixation. Inoculation with different strains resulted in different shapes of TDS bacteroids with variable nitrogen fixation. Our study provides a toolbox to study nodule development in the crop legume chickpea.
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Affiliation(s)
- Drishti Mandal
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Senjuti Sinharoy
- National Institute of Plant Genome Research, New Delhi 110067, India
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19
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Atakpa P, van Marrewijk LM, Apta-Smith M, Chakraborty S, Taylor CW. GPN does not release lysosomal Ca 2+ but evokes Ca 2+ release from the ER by increasing the cytosolic pH independently of cathepsin C. J Cell Sci 2019; 132:jcs223883. [PMID: 30617110 PMCID: PMC6382017 DOI: 10.1242/jcs.223883] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/20/2018] [Indexed: 12/15/2022] Open
Abstract
The dipeptide glycyl-l-phenylalanine 2-naphthylamide (GPN) is widely used to perturb lysosomes because its cleavage by the lysosomal enzyme cathepsin C is proposed to rupture lysosomal membranes. We show that GPN evokes a sustained increase in lysosomal pH (pHly), and transient increases in cytosolic pH (pHcyt) and Ca2+ concentration ([Ca2+]c). None of these effects require cathepsin C, nor are they accompanied by rupture of lysosomes, but they are mimicked by structurally unrelated weak bases. GPN-evoked increases in [Ca2+]c require Ca2+ within the endoplasmic reticulum (ER), but they are not mediated by ER Ca2+ channels amplifying Ca2+ release from lysosomes. GPN increases [Ca2+]c by increasing pHcyt, which then directly stimulates Ca2+ release from the ER. We conclude that physiologically relevant increases in pHcyt stimulate Ca2+ release from the ER in a manner that is independent of IP3 and ryanodine receptors, and that GPN does not selectively target lysosomes.
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Affiliation(s)
- Peace Atakpa
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Laura M van Marrewijk
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Michael Apta-Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Sumita Chakraborty
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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20
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Endolysosomal Ca 2+ Signalling and Cancer Hallmarks: Two-Pore Channels on the Move, TRPML1 Lags Behind! Cancers (Basel) 2018; 11:cancers11010027. [PMID: 30591696 PMCID: PMC6356888 DOI: 10.3390/cancers11010027] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022] Open
Abstract
The acidic vesicles of the endolysosomal (EL) system are emerging as an intracellular Ca2+ store implicated in the regulation of multiple cellular functions. The EL Ca2+ store releases Ca2+ through a variety of Ca2+-permeable channels, including Transient Receptor Potential (TRP) Mucolipin 1-3 (TRPML1-3) and two-pore channels 1-2 (TPC1-2), whereas EL Ca2+ refilling is sustained by the proton gradient across the EL membrane and/or by the endoplasmic reticulum (ER). EL Ca2+ signals may be either spatially restricted to control vesicle trafficking, autophagy and membrane repair or may be amplified into a global Ca2+ signal through the Ca2+-dependent recruitment of ER-embedded channels. Emerging evidence suggested that nicotinic acid adenine dinucleotide phosphate (NAADP)-gated TPCs sustain multiple cancer hallmarks, such as migration, invasiveness and angiogenesis. Herein, we first survey the EL Ca2+ refilling and release mechanisms and then focus on the oncogenic role of EL Ca2+ signaling. While the evidence in favor of TRPML1 involvement in neoplastic transformation is yet to be clearly provided, TPCs are emerging as an alternative target for anticancer therapies.
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21
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López E, Gómez-Gordo L, Cantonero C, Bermejo N, Pérez-Gómez J, Granados MP, Salido GM, Rosado Dionisio JA, Redondo Liberal PC. Stanniocalcin 2 Regulates Non-capacitative Ca 2+ Entry and Aggregation in Mouse Platelets. Front Physiol 2018; 9:266. [PMID: 29628897 PMCID: PMC5876523 DOI: 10.3389/fphys.2018.00266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/08/2018] [Indexed: 12/11/2022] Open
Abstract
Stanniocalcin 2 (STC2) is a fish protein that controls body Ca2+ and phosphate metabolism. STC2 has also been described in mammals, and as platelet function highly depends on both extracellular and intracellular Ca2+, we have explored its expression and function in these cells. STC2−/− mice exhibit shorter tail bleeding time than WT mice. Platelets from STC2-deficient mice showed enhanced aggregation, as well as enhanced Ca2+ mobilization in response to the physiological agonist thrombin (Thr) and the diacylglycerol analog, OAG, a selective activator of the non-capacitative Ca2+ entry channels. Interestingly, platelets from STC2−/− mice exhibit attenuated interaction between STIM1 and Orai1 in response to Thr, thus suggesting that STC2 is required for Thr-evoked STIM1-Orai1 interaction and the subsequent store-operated Ca2+ entry (SOCE). We have further assessed possible changes in the expression of the most relevant channels involved in non-capacitative Ca2+ entry in platelets. Then, protein expression of Orai3, TRPC3 and TRPC6 were evaluated by Western blotting, and the results revealed that while the expression of Orai3 was enhanced in the STC2-deficient mice, others like TRPC3 and TRPC6 remains almost unaltered. Summarizing, our results provide for the first time evidence for a role of STC2 in platelet physiology through the regulation of agonist-induced Ca2+ entry, which might be mediated by the regulation of Orai3 channel expression.
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Affiliation(s)
- Esther López
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - L Gómez-Gordo
- Department of Animal Medicine, Veterinary Faculty University of Extremadura, Cáceres, Spain
| | - Carlos Cantonero
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - Nuria Bermejo
- Hematology Unit, San Pedro de Alcantara Hospital, Cáceres, Spain
| | - Jorge Pérez-Gómez
- Faculty of Sport Sciences, University of Extremadura, Cáceres, Spain
| | - María P Granados
- Aldea Moret Health Center, Extremadura Health Service, Cáceres, Spain
| | - Gines M Salido
- Institute of Molecular Pathology Biomarkers, Cáceres, Spain
| | - Juan A Rosado Dionisio
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - Pedro C Redondo Liberal
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
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22
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Jardín I, López JJ, Diez R, Sánchez-Collado J, Cantonero C, Albarrán L, Woodard GE, Redondo PC, Salido GM, Smani T, Rosado JA. TRPs in Pain Sensation. Front Physiol 2017. [PMID: 28649203 PMCID: PMC5465271 DOI: 10.3389/fphys.2017.00392] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
According to the International Association for the Study of Pain (IASP) pain is characterized as an "unpleasant sensory and emotional experience associated with actual or potential tissue damage". The TRP super-family, compressing up to 28 isoforms in mammals, mediates a myriad of physiological and pathophysiological processes, pain among them. TRP channel might be constituted by similar or different TRP subunits, which will result in the formation of homomeric or heteromeric channels with distinct properties and functions. In this review we will discuss about the function of TRPs in pain, focusing on TRP channles that participate in the transduction of noxious sensation, especially TRPV1 and TRPA1, their expression in nociceptors and their sensitivity to a large number of physical and chemical stimuli.
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Affiliation(s)
- Isaac Jardín
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - José J López
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Raquel Diez
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - José Sánchez-Collado
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Carlos Cantonero
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Letizia Albarrán
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Pedro C Redondo
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Ginés M Salido
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, Institute of Biomedicine of Sevilla, University of SevilleSevilla, Spain
| | - Juan A Rosado
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
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23
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Lopez JJ, Salido GM, Rosado JA. Cardiovascular and Hemostatic Disorders: SOCE and Ca 2+ Handling in Platelet Dysfunction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:453-472. [PMID: 28900928 DOI: 10.1007/978-3-319-57732-6_23] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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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24
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Brailoiu GC, Brailoiu E. Modulation of Calcium Entry by the Endo-lysosomal System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:423-47. [PMID: 27161239 DOI: 10.1007/978-3-319-26974-0_18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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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Rivero-Ríos P, Fernández B, Madero-Pérez J, Lozano MR, Hilfiker S. Two-Pore Channels and Parkinson's Disease: Where's the Link? MESSENGER (LOS ANGELES, CALIF. : PRINT) 2016; 5:67-75. [PMID: 28529828 PMCID: PMC5436604 DOI: 10.1166/msr.2016.1051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Two-pore channels are endolysosomal Ca2+ release channels involved in proper trafficking to and from those organelles. They are the likely targets for the Ca2+-mobilizing messenger NAADP, and are further regulated by a variety of mechanisms including phosphoinositide levels and Rab proteins. As discussed here, recent studies highlight a role for these channels in the pathomechanism(s) underlying Parkinson's disease, with important implications for possible alternative treatment strategies.
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Affiliation(s)
- Pilar Rivero-Ríos
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - Belén Fernández
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - Jesús Madero-Pérez
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - María Romo Lozano
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - Sabine Hilfiker
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
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Melchionda M, Pittman JK, Mayor R, Patel S. Ca2+/H+ exchange by acidic organelles regulates cell migration in vivo. J Cell Biol 2016; 212:803-13. [PMID: 27002171 PMCID: PMC4810305 DOI: 10.1083/jcb.201510019] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/19/2016] [Indexed: 11/22/2022] Open
Abstract
A vertebrate Ca2+/H+ exchanger (CAX), which is part of a widespread conserved family in animals, localizes to acidic organelles, tempers evoked Ca2+ signals, and regulates cell-matrix adhesion during neural crest cell migration. Increasing evidence implicates Ca2+ in the control of cell migration. However, the underlying mechanisms are incompletely understood. Acidic Ca2+ stores are fast emerging as signaling centers. But how Ca2+ is taken up by these organelles in metazoans and the physiological relevance for migration is unclear. Here, we identify a vertebrate Ca2+/H+ exchanger (CAX) as part of a widespread family of homologues in animals. CAX is expressed in neural crest cells and required for their migration in vivo. It localizes to acidic organelles, tempers evoked Ca2+ signals, and regulates cell-matrix adhesion during migration. Our data provide new molecular insight into how Ca2+ is handled by acidic organelles and link this to migration, thereby underscoring the role of noncanonical Ca2+ stores in the control of Ca2+-dependent function.
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Affiliation(s)
- Manuela Melchionda
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, England, UK
| | - Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, England, UK
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, England, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, England, UK
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The Calcium Entry-Calcium Refilling Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:333-52. [DOI: 10.1007/978-3-319-26974-0_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Berna-Erro A, Jardín I, Smani T, Rosado JA. Regulation of Platelet Function by Orai, STIM and TRP. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:157-81. [PMID: 27161229 DOI: 10.1007/978-3-319-26974-0_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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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Shakhidzhanov SS, Shaturny VI, Panteleev MA, Sveshnikova AN. Modulation and pre-amplification of PAR1 signaling by ADP acting via the P2Y12 receptor during platelet subpopulation formation. Biochim Biophys Acta Gen Subj 2015; 1850:2518-29. [PMID: 26391841 DOI: 10.1016/j.bbagen.2015.09.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/01/2015] [Accepted: 09/11/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Two major soluble blood platelet activators are thrombin and ADP. Of these two, only thrombin can induce mitochondrial collapse and programmed cell death leading to phosphatidylserine (PS) exposure required for blood clotting reactions acceleration. Thrombin can also greatly potentiate collagen-induced PS exposure. However, ADP acting through the P2Y12 receptor was shown to increase the PS-exposing (PS+) platelets fraction produced by thrombin or thrombin-plus-collagen via an unknown mechanism. METHODS We developed a comprehensive multicompartmental computational model of platelet PAR1-and-P2Y12 calcium signal transduction that included cytoplasmic signaling, dense tubular system and mitochondria. To test model predictions, flow cytometry experiments with washed, annexin V-labeled platelets were performed. RESULTS Stimulation of thrombin receptor PAR1 in the model induced cytoplasmic calcium oscillations, calcium uptake by mitochondria, opening of the permeability transition pore and collapse of the mitochondrial membrane potential. ADP stimulation of P2Y12 led to cAMP decrease that, in turn, caused changes in phospholipase C phosphorylation by protein kinase A, increase in cytoplasmic calcium level and, consequently, PS+ platelet formation. ADP addition before stimulation of PAR1 produced much greater increase of the PS+ fraction because cAMP concentration had time to go down prior to calcium oscillations; this prediction was also tested and confirmed experimentally. CONCLUSION These results suggest a mechanism of ADP-dependent PS exposure regulation and show a likely mode of action that could be important for the PS exposure regulation in thrombi, where ADP is released before thrombin formation.
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Affiliation(s)
- S S Shakhidzhanov
- Faculty of Physics, Lomonosov Moscow State University, 1-2 Leninskie Gory, GSP-1, Moscow 119991, Rusia.
| | - V I Shaturny
- Faculty of Physics, Lomonosov Moscow State University, 1-2 Leninskie Gory, GSP-1, Moscow 119991, Rusia.
| | - M A Panteleev
- Faculty of Physics, Lomonosov Moscow State University, 1-2 Leninskie Gory, GSP-1, Moscow 119991, Rusia; Federal Research and Clinical Center of Pediatric Hematology, Oncology and Immunology, 1 Samory Mashela St, Moscow 117198, Russia; Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 4 Kosygina St, Moscow 119991, Russia; Faculty of Biological and Medical Physics, Moscow Institute of Physics and Technology, 9 Institutskii per., Dolgoprudnyi, 141700, Russia.
| | - A N Sveshnikova
- Faculty of Physics, Lomonosov Moscow State University, 1-2 Leninskie Gory, GSP-1, Moscow 119991, Rusia; Federal Research and Clinical Center of Pediatric Hematology, Oncology and Immunology, 1 Samory Mashela St, Moscow 117198, Russia; Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 4 Kosygina St, Moscow 119991, Russia.
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Lopez E, Bermejo N, Berna-Erro A, Alonso N, Salido GM, Redondo PC, Rosado JA. Relationship between calcium mobilization and platelet α- and δ-granule secretion. A role for TRPC6 in thrombin-evoked δ-granule exocytosis. Arch Biochem Biophys 2015; 585:75-81. [PMID: 26386308 DOI: 10.1016/j.abb.2015.09.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022]
Abstract
Changes in cytosolic Ca(2+) concentration ([Ca(2+)]c) regulate granule secretion in different cell types. Thrombin activates PAR1 and PAR4 receptors and promotes release of Ca(2+) from distinct intracellular stores, which, in turn, activates store-operated Ca(2+) entry (SOCE). A crucial step during platelet function is the release of physiological agonists stored in secretory granules to the extracellular compartment during activation. We aim to study the role of Ca(2+) mobilization from the extracellular compartment or from different intracellular stores in platelet granule secretion. By using flow cytometry, we have found that α- and δ-granules are secreted in thrombin-stimulated platelets in the absence of extracellular Ca(2+), and in a concentration-dependent manner. Our findings show that thrombin-stimulated granule secretion depends on Ca(2+) mobilization from intracellular stores. Analysis of the kinetics of granule secretion reveals that platelet stimulation with thrombin results in rapid release of α-granules which precedes the secretion of δ-granules. Incubation of platelets with a specific antibody, which recognizes the extracellular amino acid sequence 573-586 of TRPC6, inhibited thrombin-evoked δ-granule exocytosis. Our results indicate that the mechanisms underlying thrombin-induced α- and δ-granule secretion show differences in dependency on Ca(2+) mobilization.
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Affiliation(s)
- E Lopez
- Department of Physiology, University of Extremadura, Phycell, 10003, Spain
| | - N Bermejo
- Department of Hematology, Hospital San Pedro de Alcantara, 10003 Cáceres, Spain
| | - A Berna-Erro
- Department of Physiology, University of Extremadura, Phycell, 10003, Spain
| | - N Alonso
- Department of Hematology, Hospital Infanta Cristina, 06006 Badajoz, Spain
| | - G M Salido
- Department of Physiology, University of Extremadura, Phycell, 10003, Spain
| | - P C Redondo
- Department of Physiology, University of Extremadura, Phycell, 10003, Spain
| | - J A Rosado
- Department of Physiology, University of Extremadura, Phycell, 10003, Spain.
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Mauvezin C, Nagy P, Juhász G, Neufeld TP. Autophagosome-lysosome fusion is independent of V-ATPase-mediated acidification. Nat Commun 2015; 6:7007. [PMID: 25959678 PMCID: PMC4428688 DOI: 10.1038/ncomms8007] [Citation(s) in RCA: 288] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/23/2015] [Indexed: 12/20/2022] Open
Abstract
The ATP-dependent proton pump V-ATPase ensures low intralysosomal pH, which is essential for lysosomal hydrolase activity. Based on studies with the V-ATPase inhibitor BafilomycinA1, lysosomal acidification is also thought to be required for fusion with incoming vesicles from the autophagic and endocytic pathways. Here we show that loss of V-ATPase subunits in the Drosophila fat body causes an accumulation of non-functional lysosomes, leading to a block in autophagic flux. However, V-ATPase-deficient lysosomes remain competent to fuse with autophagosomes and endosomes, resulting in a time-dependent formation of giant autolysosomes. In contrast, BafilomycinA1 prevents autophagosome–lysosome fusion in these cells, and this defect is phenocopied by depletion of the Ca2+ pump SERCA, a secondary target of this drug. Moreover, activation of SERCA promotes fusion in a BafilomycinA1-sensitive manner. Collectively, our results indicate that lysosomal acidification is not a prerequisite for fusion, and that BafilomycinA1 inhibits fusion independent of its effect on lysosomal pH. BafilomycinA1 is an autophagy inhibitor, presumably owing to its blocking effect on the lysosomal proton pump V-ATPase. Here the authors show that V-ATPase-deficient lysosomes can still fuse with autophagosomes, showing that lysosomal acidification and fusion are two separable, independent events.
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Affiliation(s)
- Caroline Mauvezin
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
| | - Péter Nagy
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pazmany s. 1/C. 6.520, Budapest H-1117, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pazmany s. 1/C. 6.520, Budapest H-1117, Hungary
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
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Redondo PC, Rosado JA. Store-operated calcium entry: unveiling the calcium handling signalplex. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 316:183-226. [PMID: 25805125 DOI: 10.1016/bs.ircmb.2015.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) is an important mechanism for Ca(2+) influx in non-excitable cells, also present in excitable cells. The activation of store-operated channels (SOCs) is finely regulated by the filling state of the intracellular agonist-sensitive Ca(2+) compartments, and both, the mechanism of sensing the Ca(2+) stores and the nature and functional properties of the SOCs, have been a matter of intense investigation and debate. The identification of STIM1 as the endoplasmic reticulum Ca(2+) sensor and both Orai1, as the pore-forming subunit of the channels mediating the Ca(2+)-selective store-operated current, and the members of the TRPC subfamily of proteins, as the channels mediating the cation-permeable SOCs, has shed new light on the underlying events. This review summarizes the initial hypothesis and the current advances on the mechanism of activation of SOCE.
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Affiliation(s)
- Pedro C Redondo
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Cáceres, Spain
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Rivero-Ríos P, Gómez-Suaga P, Fdez E, Hilfiker S. Upstream deregulation of calcium signaling in Parkinson's disease. Front Mol Neurosci 2014; 7:53. [PMID: 24987329 PMCID: PMC4060956 DOI: 10.3389/fnmol.2014.00053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/27/2014] [Indexed: 12/21/2022] Open
Abstract
Parkinson’s disease (PD) is a major health problem affecting millions of people worldwide. Recent studies provide compelling evidence that altered Ca2+ homeostasis may underlie disease pathomechanism and be an inherent feature of all vulnerable neurons. The downstream effects of altered Ca2+ handling in the distinct subcellular organelles for proper cellular function are beginning to be elucidated. Here, we summarize the evidence that vulnerable neurons may be exposed to homeostatic Ca2+ stress which may determine their selective vulnerability, and suggest how abnormal Ca2+ handling in the distinct intracellular compartments may compromise neuronal health in the context of aging, environmental, and genetic stress. Gaining a better understanding of the varied effects of Ca2+ dyshomeostasis may allow novel combinatorial therapeutic strategies to slow PD progression.
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Affiliation(s)
- Pilar Rivero-Ríos
- Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Patricia Gómez-Suaga
- Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Elena Fdez
- Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Sabine Hilfiker
- Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas Granada, Spain
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Albarran L, Berna-Erro A, Dionisio N, Redondo PC, Lopez E, Lopez JJ, Salido GM, Brull Sabate JM, Rosado JA. TRPC6 participates in the regulation of cytosolic basal calcium concentration in murine resting platelets. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:789-96. [DOI: 10.1016/j.bbamcr.2014.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
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Glutamate release from platelets: Exocytosis versus glutamate transporter reversal. Int J Biochem Cell Biol 2013; 45:2585-95. [DOI: 10.1016/j.biocel.2013.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 08/02/2013] [Accepted: 08/07/2013] [Indexed: 11/22/2022]
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Albarrán L, Dionisio N, López E, Salido GM, Rosado JA. The membrane potential modulates thrombin-stimulated Ca²⁺ mobilization and platelet aggregation. Arch Biochem Biophys 2013; 538:130-7. [PMID: 23988350 DOI: 10.1016/j.abb.2013.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/13/2013] [Accepted: 08/18/2013] [Indexed: 11/28/2022]
Abstract
G protein-coupled receptors can be directly modulated by changes in transmembrane voltage in a variety of cell types. Here we show that, while changes in the membrane voltage itself do not induce detectable modifications in the cytosolic Ca(2+) concentration, platelet stimulation with thrombin or the PAR-1 and PAR-4 agonist peptides SFLLRN and AYPGKF, respectively, results in Ca(2+) release from intracellular stores that is sensitive to the membrane depolarisation. Direct activation of G proteins or phospholipase C by AlF4(-) and m-3M3FBS, respectively, leads to Ca(2+) release that is insensitive to changes in the membrane potential. Thapsigargin-, as well as OAG-induced Ca(2+) entry are affected by the membrane voltage, probably as a result of the modification in the driving force for Ca(2+) influx; however, hyperpolarisation does not enhance thrombin- or OAG-evoked Ca(2+) entry probably revealing the presence of a voltage-sensitive regulatory mechanism. Transmembrane voltage also modulates the activity of the plasma membrane Ca(2+)-ATPase (PMCA) most likely due to a decrease in the phosphotyrosine content of the pump. Thrombin-stimulated platelet aggregation is modulated by membrane depolarisation by a mechanism that is, at least partially, independent of Ca(2+). These observations indicate that PAR-1 and PAR-4 receptors are modulated by the membrane voltage in human platelets.
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Affiliation(s)
- Letizia Albarrán
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
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Bafilomycin A1 activates HIF-dependent signalling in human colon cancer cells via mitochondrial uncoupling. Biosci Rep 2013; 32:587-95. [PMID: 22943412 PMCID: PMC3497721 DOI: 10.1042/bsr20120085] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial uncoupling is implicated in many patho(physiological) states. Using confocal live cell imaging and an optical O2 sensing technique, we show that moderate uncoupling of the mitochondria with plecomacrolide Baf (bafilomycin A1) causes partial depolarization of the mitochondria and deep sustained deoxygenation of human colon cancer HCT116 cells subjected to 6% atmospheric O2. A decrease in iO2 (intracellular O2) to 0–10 μM, induced by Baf, is sufficient for stabilization of HIFs (hypoxia inducible factors) HIF-1α and HIF-2α, coupled with an increased expression of target genes including GLUT1 (glucose transporter 1), HIF PHD2 (prolyl hydroxylase domain 2) and CAIX (carbonic anhydrase IX). Under the same hypoxic conditions, treatment with Baf causes neither decrease in iO2 nor HIF-α stabilization in the low-respiring HCT116 cells deficient in COX (cytochrome c-oxidase). Both cell types display equal capacities for HIF-α stabilization by hypoxia mimetics DMOG (dimethyloxalylglycine) and CoCl2, thus suggesting that the effect of Baf under hypoxia is driven mainly by mitochondrial respiration. Altogether, by activating HIF signalling under moderate hypoxia, mitochondrial uncoupling can play an important regulatory role in colon cancer metabolism and modulate adaptation of cancer cells to natural hypoxic environments.
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Smani T, Dionisio N, López JJ, Berna-Erro A, Rosado JA. Cytoskeletal and scaffolding proteins as structural and functional determinants of TRP channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:658-64. [PMID: 23333715 DOI: 10.1016/j.bbamem.2013.01.009] [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] [Received: 10/04/2012] [Revised: 12/30/2012] [Accepted: 01/10/2013] [Indexed: 12/14/2022]
Abstract
Transient receptor potential (TRP) channels are six transmembrane-spanning proteins, with variable selectivity for cations, that play a relevant role in intracellular Ca(2+) homeostasis. There is a large body of evidence that shows association of TRP channels with the actin cytoskeleton or even the microtubules and demonstrating the functional importance of this interaction for TRP channel function. Conversely, cation currents through TRP channels have also been found to modulate cytoskeleton rearrangements. The interplay between TRP channels and the cytoskeleton has been demonstrated to be essential for full activation of a variety of cellular functions. Furthermore, TRP channels have been reported to take part of macromolecular complexes including different signal transduction proteins. Scaffolding proteins play a relevant role in the association of TRP proteins with other signaling molecules into specific microdomains. Especially relevant are the roles of the Homer family members for the regulation of TRPC channel gating in mammals and INAD in the modulation of Drosophila TRP channels. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Tarik Smani
- Institute of Biomedicine of Seville, Seville, Spain
| | - Natalia Dionisio
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain
| | - José J López
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain
| | - Alejandro Berna-Erro
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain.
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Thrombin-stimulated discharge of calcium stores in human platelets: analysis of experimental data. Arch Biochem Biophys 2012; 526:78-83. [PMID: 22846427 DOI: 10.1016/j.abb.2012.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/18/2012] [Accepted: 07/19/2012] [Indexed: 11/21/2022]
Abstract
The purpose of this research was to analyze experimental data concerning thrombin-stimulated discharge of calcium stores in human platelets contained in calcium-free medium in view of better understanding the mechanisms involved in calcium fluxes. The model curves are reasonably close to experimental data; the parameters of the models are related to the properties of the entities responsible for control or maintenance of cytosolic calcium concentration. It has been shown that: (a) time-course of calcium concentration in cytosol of human platelets can be acceptably modeled on the basis of reasonable assumptions concerning agonist stimulated calcium redistribution in cellular compartments; (b) those assumptions are of fundamental importance for the model (c) some parameters of the model (taken arbitrarily) cannot be estimated independently of others from fitting the model to experimental data available; (d) special experiments are necessary to determine the unknown parameters; (e) agonist-stimulated change of the permeability of endomembrane of calcium stores can be regarded as a pulse of the permeability; it can be modeled as a sequence of transitions of the system from inactive to active and to inactive state again.
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Abstract
The stromal interaction molecules STIM1 and STIM2 are Ca2+ sensors, mostly located in the endoplasmic reticulum, that detect changes in the intraluminal Ca2+ concentration and communicate this information to plasma membrane store-operated channels, including members of the Orai family, thus mediating store-operated Ca2+ entry (SOCE). Orai and STIM proteins are almost ubiquitously expressed in human cells, where SOCE has been reported to play a relevant functional role. The phenotype of patients bearing mutations in STIM and Orai proteins, together with models of STIM or Orai deficiency in mice, as well as other organisms such as Drosophila melanogaster, have provided compelling evidence on the relevant role of these proteins in cellular physiology and pathology. Orai1-deficient patients suffer from severe immunodeficiency, congenital myopathy, chronic pulmonary disease, anhydrotic ectodermal dysplasia and defective dental enamel calcification. STIM1-deficient patients showed similar abnormalities, as well as autoimmune disorders. This review summarizes the current evidence that identifies and explains diseases induced by disturbances in SOCE due to deficiencies or mutations in Orai and STIM proteins.
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Affiliation(s)
- A Berna-Erro
- Department of Physiology, University of Extremadura, Cáceres, Spain
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Álvarez J. Calcium dynamics in the secretory granules of neuroendocrine cells. Cell Calcium 2012; 51:331-7. [DOI: 10.1016/j.ceca.2011.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/22/2011] [Accepted: 12/04/2011] [Indexed: 01/29/2023]
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Abstract
Platelets play a vital role in maintaining haemostasis. Human platelet activation depends on Ca2+ release, leading to cell activation, granule secretion and aggregation. NAADP (nicotinic acid-adenine dinucleotide phosphate) is a Ca2+-releasing second messenger that acts on acidic Ca2+ stores and is used by a number of mammalian systems. In human platelets, NAADP has been shown to release Ca2+ in permeabilized human platelets and contribute to thrombin-mediated platelet activation. In the present study, we have further characterized NAADP-mediated Ca2+ release in human platelets in response to both thrombin and the GPVI (glycoprotein VI)-specific agonist CRP (collagen-related peptide). Using a radioligand-binding assay, we reveal an NAADP-binding site in human platelets, indicative of a platelet NAADP receptor. We also found that NAADP releases loaded 45Ca2+ from intracellular stores and that total platelet Ca2+ release is inhibited by the proton ionophore nigericin. Ned-19, a novel cell-permeant NAADP receptor antagonist, competes for the NAADP-binding site in platelets and can inhibit both thrombin- and CRP-induced Ca2+ release in human platelets. Ned-19 has an inhibitory effect on platelet aggregation, secretion and spreading. In addition, Ned-19 extends the clotting time in whole-blood samples. We conclude that NAADP plays an important role in human platelet function. Furthermore, the development of Ned-19 as an NAADP receptor antagonist provides a potential avenue for platelet-targeted therapy and the regulation of thrombosis.
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Molecular mechanisms of endolysosomal Ca2+ signalling in health and disease. Biochem J 2011; 439:349-74. [PMID: 21992097 DOI: 10.1042/bj20110949] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Endosomes, lysosomes and lysosome-related organelles are emerging as important Ca2+ storage cellular compartments with a central role in intracellular Ca2+ signalling. Endocytosis at the plasma membrane forms endosomal vesicles which mature to late endosomes and culminate in lysosomal biogenesis. During this process, acquisition of different ion channels and transporters progressively changes the endolysosomal luminal ionic environment (e.g. pH and Ca2+) to regulate enzyme activities, membrane fusion/fission and organellar ion fluxes, and defects in these can result in disease. In the present review we focus on the physiology of the inter-related transport mechanisms of Ca2+ and H+ across endolysosomal membranes. In particular, we discuss the role of the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) as a major regulator of Ca2+ release from endolysosomes, and the recent discovery of an endolysosomal channel family, the TPCs (two-pore channels), as its principal intracellular targets. Recent molecular studies of endolysosomal Ca2+ physiology and its regulation by NAADP-gated TPCs are providing exciting new insights into the mechanisms of Ca2+-signal initiation that control a wide range of cellular processes and play a role in disease. These developments underscore a new central role for the endolysosomal system in cellular Ca2+ regulation and signalling.
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Borisova T, Kasatkina L, Ostapchenko L. The proton gradient of secretory granules and glutamate transport in blood platelets during cholesterol depletion of the plasma membrane by methyl-β-cyclodextrin. Neurochem Int 2011; 59:965-75. [DOI: 10.1016/j.neuint.2011.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 07/07/2011] [Accepted: 07/11/2011] [Indexed: 10/17/2022]
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46
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Alexandru N, Popov D, Georgescu A. Platelet dysfunction in vascular pathologies and how can it be treated. Thromb Res 2011; 129:116-26. [PMID: 22035630 DOI: 10.1016/j.thromres.2011.09.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/19/2011] [Accepted: 09/22/2011] [Indexed: 12/17/2022]
Abstract
Cardiovascular diseases are one of the leading causes of morbidity and mortality in industrialized countries, and although many processes play a role in the development of vascular disease, thrombosis is the primary event that precipitates stroke and acute coronary syndromes. The blood platelets are of significant importance in medicine. These cells are involved in many physiological processes, particularly haemostasis through their ability to aggregate and form clots in response to activation. In addition, these dynamic cells display activities that extend beyond thrombosis, including an important role in initiating and sustaining vascular inflammation. The expansion of knowledge from basic and clinical research has highlighted the critical position of platelets in several inflammatory diseases such as arthritis and atherosclerosis. Platelets are emerging as important mediators of inflammation and provide important signals to mediate phenotype of other blood and vascular cells. The important role of platelets in arterial thrombosis and the onset of acute myocardial infarction after atherosclerotic plaque rupture make inhibition of platelet aggregation a critical step in preventing thrombotic events associated with stroke, heart attack, and peripheral arterial thrombosis. However, the use of platelet inhibitors for thrombosis prevention must seek a delicate balance between inhibiting platelet activation and an associated increased bleeding risk. The aim of this review is to up-date the knowledge on platelets physiology and dysfunction in pathologies, such as diabetes mellitus, hypercholesterolemia, and hypertension, emphasizing the link between platelets and the inflammation-related atherosclerosis. The review evaluates the opportunities offered by the novel platelet inhibitors to efficiently alleviate the thrombotic events.
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Rosado J. Acidic Ca2+ stores in platelets. Cell Calcium 2011; 50:168-74. [DOI: 10.1016/j.ceca.2010.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 11/25/2010] [Accepted: 11/27/2010] [Indexed: 02/06/2023]
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Juška A. Calcium fluxes into and out of cytosol in human platelets: analysis of experimental data. Biochem Biophys Res Commun 2011; 412:537-42. [PMID: 21798249 DOI: 10.1016/j.bbrc.2011.07.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 07/11/2011] [Indexed: 12/11/2022]
Abstract
The purpose of this research was to analyse experimental data concerning cytosolic calcium concentration in view of the mechanisms involved in calcium fluxes in human platelets. The parameters of model curves are related to the properties of the entities responsible for control or maintenance of cytosolic calcium concentration. It has been shown that: (a) biphasicity of increase in cytosolic calcium concentration caused by inhibition of SERCAs either by TBHQ and TG or by TG alone is related to fast and slow discharge of acidic calcium stores and DTS; (b) biphasicity of decline in cytosolic calcium concentration after its rise caused by stimulation of platelets by the agonists is related to non-synchronous extrusion of calcium by PMCA and NCX; (c) NCX is active only in calcium containing medium: calcium ion(s) are necessary to be bound to the site(s) located on the medium-facing side of the (macro)molecule; (d) PMCA is likely to be activated either by binding calcium ion(s) to the site(s) located on its cytosol-facing side or by unbinding identical ion(s) from the site(s) on its medium-facing side.
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Affiliation(s)
- Alfonsas Juška
- Vilniaus Gedimino technikos universitetas, Vilnius, Lithuania.
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49
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Abstract
Agonist-sensitive intracellular Ca2+ stores may be heterogeneous and exhibit distinct functional features. We have studied the properties of intracellular Ca2+ stores using targeted aequorins for selective measurements in different subcellular compartments. Both, HEK-293T [HEK (human embryonic kidney)-293 cells expressing the large T-antigen of SV40 (simian virus 40)] and HeLa cells accumulated Ca2+ into the ER (endoplasmic reticulum) to near millimolar concentrations and the IP3-generating agonists, carbachol and ATP, mobilized this Ca2+ pool. We find in HEK-293T, but not in HeLa cells, a distinct agonist-releasable Ca2+ pool insensitive to the SERCA (sarco/endoplasmic reticulum Ca2+ ATPase) inhibitor TBH [2,5-di-(t-butyl)-benzohydroquinone]. TG (thapsigargin) and CPA (cyclopiazonic acid) completely emptied this pool, whereas lysosomal disruption or manoeuvres collapsing endomembrane pH gradients did not. Our results indicate that SERCA3d is important for filling the TBH-resistant store as: (i) SERCA3d is more abundant in HEK-293T than in HeLa cells; (ii) the SERCA 3 ATPase activity of HEK-293T cells is not fully blocked by TBH; and (iii) the expression of SERCA3d in HeLa cells generated a TBH-resistant agonist-mobilizable compartment in the ER. Therefore the distribution of SERCA isoforms may originate the heterogeneity of the ER Ca2+ stores and this may be the basis for store specialization in diverse functions. This adds to recent evidence indicating that SERCA3 isoforms may subserve important physiological and pathophysiological mechanisms.
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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. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 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] [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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