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Chen W, Motsinger MM, Li J, Bohannon KP, Hanson PI. Ca 2+-sensor ALG-2 engages ESCRTs to enhance lysosomal membrane resilience to osmotic stress. Proc Natl Acad Sci U S A 2024; 121:e2318412121. [PMID: 38781205 PMCID: PMC11145288 DOI: 10.1073/pnas.2318412121] [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: 10/24/2023] [Accepted: 04/10/2024] [Indexed: 05/25/2024] Open
Abstract
Lysosomes are central players in cellular catabolism, signaling, and metabolic regulation. Cellular and environmental stresses that damage lysosomal membranes can compromise their function and release toxic content into the cytoplasm. Here, we examine how cells respond to osmotic stress within lysosomes. Using sensitive assays of lysosomal leakage and rupture, we examine acute effects of the osmotic disruptant glycyl-L-phenylalanine 2-naphthylamide (GPN). Our findings reveal that low concentrations of GPN rupture a small fraction of lysosomes, but surprisingly trigger Ca2+ release from nearly all. Chelating cytoplasmic Ca2+ makes lysosomes more sensitive to GPN-induced rupture, suggesting a role for Ca2+ in lysosomal membrane resilience. GPN-elicited Ca2+ release causes the Ca2+-sensor Apoptosis Linked Gene-2 (ALG-2), along with Endosomal Sorting Complex Required for Transport (ESCRT) proteins it interacts with, to redistribute onto lysosomes. Functionally, ALG-2, but not its ESCRT binding-disabled ΔGF122 splice variant, increases lysosomal resilience to osmotic stress. Importantly, elevating juxta-lysosomal Ca2+ without membrane damage by activating TRPML1 also recruits ALG-2 and ESCRTs, protecting lysosomes from subsequent osmotic rupture. These findings reveal that Ca2+, through ALG-2, helps bring ESCRTs to lysosomes to enhance their resilience and maintain organelle integrity in the face of osmotic stress.
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Affiliation(s)
- Wei Chen
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - Madeline M. Motsinger
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - Jiaqian Li
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - Kevin P. Bohannon
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
| | - Phyllis I. Hanson
- Department of Biological Chemistry, University of Michigan School of Medicine, Ann Arbor, MI48109
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI48109
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2
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Zierke L, John D, Gischke M, Tran QT, Sendler M, Weiss FU, Bornscheuer UT, Ritter C, Lerch MM, Aghdassi AA. Initiation of acute pancreatitis in mice is independent of fusion between lysosomes and zymogen granules. Cell Mol Life Sci 2024; 81:207. [PMID: 38709385 DOI: 10.1007/s00018-024-05247-7] [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: 01/25/2024] [Revised: 04/05/2024] [Accepted: 04/20/2024] [Indexed: 05/07/2024]
Abstract
The co-localization of the lysosomal protease cathepsin B (CTSB) and the digestive zymogen trypsinogen is a prerequisite for the initiation of acute pancreatitis. However, the exact molecular mechanisms of co-localization are not fully understood. In this study, we investigated the role of lysosomes in the onset of acute pancreatitis by using two different experimental approaches. Using an acinar cell-specific genetic deletion of the ras-related protein Rab7, important for intracellular vesicle trafficking and fusion, we analyzed the subcellular distribution of lysosomal enzymes and the severity of pancreatitis in vivo and ex vivo. Lysosomal permeabilization was performed by the lysosomotropic agent Glycyl-L-phenylalanine 2-naphthylamide (GPN). Acinar cell-specific deletion of Rab7 increased endogenous CTSB activity and despite the lack of re-distribution of CTSB from lysosomes to the secretory vesicles, the activation of CTSB localized in the zymogen compartment still took place leading to trypsinogen activation and pancreatic injury. Disease severity was comparable to controls during the early phase but more severe at later time points. Similarly, GPN did not prevent CTSB activation inside the secretory compartment upon caerulein stimulation, while lysosomal CTSB shifted to the cytosol. Intracellular trypsinogen activation was maintained leading to acute pancreatitis similar to controls. Our results indicate that initiation of acute pancreatitis seems to be independent of the presence of lysosomes and that fusion of lysosomes and zymogen granules is dispensable for the disease onset. Intact lysosomes rather appear to have protective effects at later disease stages.
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Affiliation(s)
- Lukas Zierke
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
| | - Daniel John
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
| | - Marcel Gischke
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
| | - Quang Trung Tran
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
- Department of Internal Medicine, Hue University, Hue, Vietnam
| | - Matthias Sendler
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
| | - Frank Ulrich Weiss
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany
| | - Uwe T Bornscheuer
- Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, University of Greifswald, Greifswald, Germany
| | - Christoph Ritter
- Department of Pharmacy, University of Greifswald, Greifswald, Germany
| | | | - Ali A Aghdassi
- Department of Medicine A, University Medicine Greifswald, Ferdinand-Sauerbruch Str, 17475, Greifswald, Germany.
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3
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Okafor M, Champomier O, Raibaut L, Ozkan S, El Kholti N, Ory S, Chasserot-Golaz S, Gasman S, Hureau C, Faller P, Vitale N. Restoring cellular copper homeostasis in Alzheimer disease: a novel peptide shuttle is internalized by an ATP-dependent endocytosis pathway involving Rab5- and Rab14-endosomes. Front Mol Biosci 2024; 11:1355963. [PMID: 38645276 PMCID: PMC11026709 DOI: 10.3389/fmolb.2024.1355963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/11/2024] [Indexed: 04/23/2024] Open
Abstract
CPPs, or Cell-Penetrating Peptides, offer invaluable utility in disease treatment due to their ability to transport various therapeutic molecules across cellular membranes. Their unique characteristics, such as biocompatibility and low immunogenicity, make them ideal candidates for delivering drugs, genes, or imaging agents directly into cells. This targeted delivery enhances treatment efficacy while minimizing systemic side effects. CPPs exhibit versatility, crossing biological barriers and reaching intracellular targets that conventional drugs struggle to access. This capability holds promise in treating a wide array of diseases, including cancer, neurodegenerative disorders, and infectious diseases, offering a potent avenue for innovative and targeted therapies, yet their precise mechanism of cell entry is far from being fully understood. In order to correct Cu dysregulation found in various pathologies such as Alzheimer disease, we have recently conceived a peptide Cu(II) shuttle, based on the αR5W4 CPP, which, when bound to Cu(II), is able to readily enter a neurosecretory cell model, and release bioavailable Cu in cells. Furthermore, this shuttle has the capacity to protect cells in culture against oxidative stress-induced damage which occurs when Cu binds to the Aβ peptide. The aim of this study was therefore to characterize the cell entry route used by this shuttle and determine in which compartment Cu is released. Pharmacological treatments, siRNA silencing and colocalization experiments with GFP-Rab fusion proteins, indicate that the shuttle is internalized by an ATP-dependent endocytosis pathway involving both Rab5 and Rab14 endosomes route and suggest an early release of Cu from the shuttle.
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Affiliation(s)
- Michael Okafor
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
- Institut de Chimie—UMR7177, Université de Strasbourg, Centre National de la Recherche Scientifique, Strasbourg, France
| | - Olivia Champomier
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
- Institut de Chimie—UMR7177, Université de Strasbourg, Centre National de la Recherche Scientifique, Strasbourg, France
| | - Laurent Raibaut
- Institut de Chimie—UMR7177, Université de Strasbourg, Centre National de la Recherche Scientifique, Strasbourg, France
| | - Sebahat Ozkan
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
| | - Naima El Kholti
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
| | - Sylvette Chasserot-Golaz
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
| | - Christelle Hureau
- Laboratoire de Chimie de Coordination, Centre National de la Recherche Scientifique UPR8241, Université de Toulouse, Toulouse, France
| | - Peter Faller
- Institut de Chimie—UMR7177, Université de Strasbourg, Centre National de la Recherche Scientifique, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives—Centre National de la Recherche Scientifique UPR3212, Université de Strasbourg, Strasbourg, France
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Chen W, Motsinger MM, Li J, Bohannon KP, Hanson PI. Ca 2+ -sensor ALG-2 engages ESCRTs to enhance lysosomal membrane resilience to osmotic stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.04.578682. [PMID: 38352356 PMCID: PMC10862787 DOI: 10.1101/2024.02.04.578682] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Lysosomes are central players in cellular catabolism, signaling, and metabolic regulation. Cellular and environmental stresses that damage lysosomal membranes can compromise their function and release toxic content into the cytoplasm. Here, we examine how cells respond to osmotic stress within lysosomes. Using sensitive assays of lysosomal leakage and rupture, we examine acute effects of the cathepsin C-metabolized osmotic disruptant glycyl-L-phenylalanine 2-naphthylamide (GPN). Our findings reveal that widely used concentrations of GPN rupture only a small fraction of lysosomes, but surprisingly trigger Ca 2+ release from nearly all. Chelating cytoplasmic Ca 2+ using BAPTA makes lysosomes more likely to rupture under GPN-induced stress, suggesting that Ca 2+ plays a role in protecting or rapidly repairing lysosomal membranes. Mechanistically, we establish that GPN causes the Ca 2+ -sensitive protein Apoptosis Linked Gene-2 (ALG-2) and interacting ESCRT proteins to redistribute onto lysosomes, improving their resistance to membrane stress created by GPN as well as the lysosomotropic drug chlorpromazine. Furthermore, we show that activating the cation channel TRPML1, with or without blocking the endoplasmic reticulum Ca 2+ pump, creates local Ca 2+ signals that protect lysosomes from rupture by recruiting ALG-2 and ESCRTs without any membrane damage. These findings reveal that Ca 2+ , through ALG-2, helps bring ESCRTs to lysosomes to enhance their resilience and maintain organelle integrity in the face of osmotic stress. SIGNIFICANCE As the degradative hub of the cell, lysosomes are full of toxic content that can spill into the cytoplasm. There has been much recent interest in how cells sense and repair lysosomal membrane damage using ESCRTs and cholesterol to rapidly fix "nanoscale damage". Here, we extend understanding of how ESCRTs contribute by uncovering a preventative role of the ESCRT machinery. We show that ESCRTs, when recruited by the Ca 2+ -sensor ALG-2, play a critical role in stabilizing the lysosomal membrane against osmotically-induced rupture. This finding suggests that cells have mechanisms not just for repairing but also for actively protecting lysosomes from stress-induced membrane damage.
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5
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Wahl-Schott C, Freichel M, Hennis K, Philippaert K, Ottenheijm R, Tsvilovskyy V, Varbanov H. Characterization of Endo-Lysosomal Cation Channels Using Calcium Imaging. Handb Exp Pharmacol 2023; 278:277-304. [PMID: 36894791 DOI: 10.1007/164_2023_637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Endo-lysosomes are membrane-bound acidic organelles that are involved in endocytosis, recycling, and degradation of extracellular and intracellular material. The membranes of endo-lysosomes express several Ca2+-permeable cation ion channels, including two-pore channels (TPC1-3) and transient receptor potential mucolipin channels (TRPML1-3). In this chapter, we will describe four different state-of-the-art Ca2+ imaging approaches, which are well-suited to investigate the function of endo-lysosomal cation channels. These techniques include (1) global cytosolic Ca2+ measurements, (2) peri-endo-lysosomal Ca2+ imaging using genetically encoded Ca2+ sensors that are directed to the cytosolic endo-lysosomal membrane surface, (3) Ca2+ imaging of endo-lysosomal cation channels, which are engineered in order to redirect them to the plasma membrane in combination with approaches 1 and 2, and (4) Ca2+ imaging by directing Ca2+ indicators to the endo-lysosomal lumen. Moreover, we will review useful small molecules, which can be used as valuable tools for endo-lysosomal Ca2+ imaging. Rather than providing complete protocols, we will discuss specific methodological issues related to endo-lysosomal Ca2+ imaging.
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Affiliation(s)
- Christian Wahl-Schott
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany.
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany. .,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany.
| | - Konstantin Hennis
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany
| | - Koenraad Philippaert
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Roger Ottenheijm
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Volodymyr Tsvilovskyy
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Hristo Varbanov
- Institut für Neurophysiologie, Medizinische Hochschule Hannover(MHH), Hannover, Germany
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6
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Scorza SI, Milano S, Saponara I, Certini M, De Zio R, Mola MG, Procino G, Carmosino M, Moccia F, Svelto M, Gerbino A. TRPML1-Induced Lysosomal Ca 2+ Signals Activate AQP2 Translocation and Water Flux in Renal Collecting Duct Cells. Int J Mol Sci 2023; 24:ijms24021647. [PMID: 36675161 PMCID: PMC9861594 DOI: 10.3390/ijms24021647] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/04/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Lysosomes are acidic Ca2+ storage organelles that actively generate local Ca2+ signaling events to regulate a plethora of cell functions. Here, we characterized lysosomal Ca2+ signals in mouse renal collecting duct (CD) cells and we assessed their putative role in aquaporin 2 (AQP2)-dependent water reabsorption. Bafilomycin A1 and ML-SA1 triggered similar Ca2+ oscillations, in the absence of extracellular Ca2+, by alkalizing the acidic lysosomal pH or activating the lysosomal cation channel mucolipin 1 (TRPML1), respectively. TRPML1-dependent Ca2+ signals were blocked either pharmacologically or by lysosomes' osmotic permeabilization, thus indicating these organelles as primary sources of Ca2+ release. Lysosome-induced Ca2+ oscillations were sustained by endoplasmic reticulum (ER) Ca2+ content, while bafilomycin A1 and ML-SA1 did not directly interfere with ER Ca2+ homeostasis per se. TRPML1 activation strongly increased AQP2 apical expression and depolymerized the actin cytoskeleton, thereby boosting water flux in response to an hypoosmotic stimulus. These effects were strictly dependent on the activation of the Ca2+/calcineurin pathway. Conversely, bafilomycin A1 led to perinuclear accumulation of AQP2 vesicles without affecting water permeability. Overall, lysosomal Ca2+ signaling events can be differently decoded to modulate Ca2+-dependent cellular functions related to the dock/fusion of AQP2-transporting vesicles in principal cells of the CD.
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Affiliation(s)
- Simona Ida Scorza
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Serena Milano
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Ilenia Saponara
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Maira Certini
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Roberta De Zio
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Maria Grazia Mola
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy
| | - Francesco Moccia
- Department of Biology and Biotechnology Lazzaro Spallanzani, University of Pavia, 27100 Pavia, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
- Correspondence: ; Tel.: +39-0805443334
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7
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Anti-Inflammatory Effects of Cannabigerol in Rheumatoid Arthritis Synovial Fibroblasts and Peripheral Blood Mononuclear Cell Cultures Are Partly Mediated by TRPA1. Int J Mol Sci 2023; 24:ijms24010855. [PMID: 36614296 PMCID: PMC9820932 DOI: 10.3390/ijms24010855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 01/06/2023] Open
Abstract
Since its medical legalization, cannabis preparations containing the major phytocannabinoids (cannabidiol (CBD) and δ9-tetrahydrocannabinol (THC)) have been used by patients with rheumatoid arthritis (RA) to alleviate pain and inflammation. However, minor cannabinoids such as cannabigerol (CBG) also demonstrated anti-inflammatory properties, but due to the lack of studies, they are not widely used. CBG binds several cellular target proteins such as cannabinoid and α2-adrenergic receptors, but it also ligates several members of the transient potential receptor (TRP) family with TRPA1 being the main target. TRPA1 is not only involved in nnociception, but it also protects cells from apoptosis under oxidative stress conditions. Therefore, modulation of TRPA1 signaling by CBG might be used to modulate disease activity in RA as this autoimmune disease is accompanied by oxidative stress and subsequent activation of pro-inflammatory pathways. Rheumatoid synovial fibroblasts (RASF) were stimulated or not with tumor necrosis factor (TNF) for 72 h to induce TRPA1 protein. CBG increased intracellular calcium levels in TNF-stimulated RASF but not unstimulated RASF in a TRPA1-dependent manner. In addition, PoPo3 uptake, a surrogate marker for drug uptake, was enhanced by CBG. RASF cell viability, IL-6 and IL-8 production were decreased by CBG. In peripheral blood mononuclear cell cultures (PBMC) alone or together with RASF, CBG-modulated interleukin (IL)-6, IL-10, TNF and immunoglobulin M and G production which was dependent on activation stimulus (T cell-dependent or independent). However, effects on PBMCs were only partially mediated by TRPA1 as the antagonist A967079 did inhibit some but not all effects of CBG on cytokine production. In contrast, TRPA1 antagonism even enhanced the inhibitory effects of CBG on immunoglobulin production. CBG showed broad anti-inflammatory effects in isolated RASF, PBMC and PBMC/RASF co-cultures. As CBG is non-psychotropic, it might be used as add-on therapy in RA to reduce IL-6 and autoantibody levels.
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8
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Steiner P, Arlt E, Boekhoff I, Gudermann T, Zierler S. TPC Functions in the Immune System. Handb Exp Pharmacol 2023; 278:71-92. [PMID: 36639434 DOI: 10.1007/164_2022_634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Two-pore channels (TPCs) are novel intracellular cation channels, which play a key role in numerous (patho-)physiological and immunological processes. In this chapter, we focus on their function in immune cells and immune reactions. Therefore, we first give an overview of the cellular immune response and the partaking immune cells. Second, we concentrate on ion channels which in the past have been shown to play an important role in the regulation of immune cells. The main focus is then directed to TPCs, which are primarily located in the membranes of acidic organelles, such as lysosomes or endolysosomes but also certain other vesicles. They regulate Ca2+ homeostasis and thus Ca2+ signaling in immune cells. Due to this important functional role, TPCs are enjoying increasing attention within the field of immunology in the last few decades but are also becoming more pertinent as pharmacological targets for the treatment of pro-inflammatory diseases such as allergic hypersensitivity. However, to uncover the precise molecular mechanism of TPCs in immune cell responses, further molecular, genetic, and ultrastructural investigations on TPCs are necessary, which then may pave the way to develop novel therapeutic strategies to treat diseases such as anaphylaxis more specifically.
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Affiliation(s)
- Philip Steiner
- Institute of Pharmacology, Faculty of Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Elisabeth Arlt
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Ingrid Boekhoff
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Susanna Zierler
- Institute of Pharmacology, Faculty of Medicine, Johannes Kepler University Linz, Linz, Austria.
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
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9
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Barral DC, Staiano L, Guimas Almeida C, Cutler DF, Eden ER, Futter CE, Galione A, Marques ARA, Medina DL, Napolitano G, Settembre C, Vieira OV, Aerts JMFG, Atakpa‐Adaji P, Bruno G, Capuozzo A, De Leonibus E, Di Malta C, Escrevente C, Esposito A, Grumati P, Hall MJ, Teodoro RO, Lopes SS, Luzio JP, Monfregola J, Montefusco S, Platt FM, Polishchuck R, De Risi M, Sambri I, Soldati C, Seabra MC. Current methods to analyze lysosome morphology, positioning, motility and function. Traffic 2022; 23:238-269. [PMID: 35343629 PMCID: PMC9323414 DOI: 10.1111/tra.12839] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 01/09/2023]
Abstract
Since the discovery of lysosomes more than 70 years ago, much has been learned about the functions of these organelles. Lysosomes were regarded as exclusively degradative organelles, but more recent research has shown that they play essential roles in several other cellular functions, such as nutrient sensing, intracellular signalling and metabolism. Methodological advances played a key part in generating our current knowledge about the biology of this multifaceted organelle. In this review, we cover current methods used to analyze lysosome morphology, positioning, motility and function. We highlight the principles behind these methods, the methodological strategies and their advantages and limitations. To extract accurate information and avoid misinterpretations, we discuss the best strategies to identify lysosomes and assess their characteristics and functions. With this review, we aim to stimulate an increase in the quantity and quality of research on lysosomes and further ground-breaking discoveries on an organelle that continues to surprise and excite cell biologists.
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Affiliation(s)
- Duarte C. Barral
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Leopoldo Staiano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Institute for Genetic and Biomedical ResearchNational Research Council (CNR)MilanItaly
| | | | - Dan F. Cutler
- MRC Laboratory for Molecular Cell BiologyUniversity College LondonLondonUK
| | - Emily R. Eden
- University College London (UCL) Institute of OphthalmologyLondonUK
| | - Clare E. Futter
- University College London (UCL) Institute of OphthalmologyLondonUK
| | | | | | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Clinical Medicine and Surgery DepartmentFederico II UniversityNaplesItaly
| | - Otília V. Vieira
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | | | | | - Gemma Bruno
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Elvira De Leonibus
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Institute of Biochemistry and Cell Biology, CNRRomeItaly
| | - Chiara Di Malta
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | | | | | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Michael J. Hall
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Rita O. Teodoro
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Susana S. Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - J. Paul Luzio
- Cambridge Institute for Medical ResearchUniversity of CambridgeCambridgeUK
| | | | | | | | | | - Maria De Risi
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Chiara Soldati
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Miguel C. Seabra
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
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10
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Faris P, Casali C, Negri S, Iengo L, Biggiogera M, Maione AS, Moccia F. Nicotinic Acid Adenine Dinucleotide Phosphate Induces Intracellular Ca2+ Signalling and Stimulates Proliferation in Human Cardiac Mesenchymal Stromal Cells. Front Cell Dev Biol 2022; 10:874043. [PMID: 35392169 PMCID: PMC8980055 DOI: 10.3389/fcell.2022.874043] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/24/2022] [Indexed: 12/18/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a newly discovered second messenger that gates two pore channels 1 (TPC1) and 2 (TPC2) to elicit endo-lysosomal (EL) Ca2+ release. NAADP-induced lysosomal Ca2+ release may be amplified by the endoplasmic reticulum (ER) through the Ca2+-induced Ca2+ release (CICR) mechanism. NAADP-induced intracellular Ca2+ signals were shown to modulate a growing number of functions in the cardiovascular system, but their occurrence and role in cardiac mesenchymal stromal cells (C-MSCs) is still unknown. Herein, we found that exogenous delivery of NAADP-AM induced a robust Ca2+ signal that was abolished by disrupting the lysosomal Ca2+ store with Gly-Phe β-naphthylamide, nigericin, and bafilomycin A1, and blocking TPC1 and TPC2, that are both expressed at protein level in C-MSCs. Furthermore, NAADP-induced EL Ca2+ release resulted in the Ca2+-dependent recruitment of ER-embedded InsP3Rs and SOCE activation. Transmission electron microscopy revealed clearly visible membrane contact sites between lysosome and ER membranes, which are predicted to provide the sub-cellular framework for lysosomal Ca2+ to recruit ER-embedded InsP3Rs through CICR. NAADP-induced EL Ca2+ mobilization via EL TPC was found to trigger the intracellular Ca2+ signals whereby Fetal Bovine Serum (FBS) induces C-MSC proliferation. Furthermore, NAADP-evoked Ca2+ release was required to mediate FBS-induced extracellular signal-regulated kinase (ERK), but not Akt, phosphorylation in C-MSCs. These finding support the notion that NAADP-induced TPC activation could be targeted to boost proliferation in C-MSCs and pave the way for future studies assessing whether aberrant NAADP signaling in C-MSCs could be involved in cardiac disorders.
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Affiliation(s)
- Pawan Faris
- Laboratory of General Physiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
| | - Claudio Casali
- Laboratory of Cell Biology and Neurobiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
| | - Sharon Negri
- Laboratory of General Physiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
| | - Lara Iengo
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino, IRCCS, Milan, Italy
| | - Marco Biggiogera
- Laboratory of Cell Biology and Neurobiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
| | - Angela Serena Maione
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino, IRCCS, Milan, Italy
- *Correspondence: Angela Serena Maione, ; Francesco Moccia,
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
- *Correspondence: Angela Serena Maione, ; Francesco Moccia,
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11
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Grochowska KM, Andres‐Alonso M, Karpova A, Kreutz MR. The needs of a synapse—How local organelles serve synaptic proteostasis. EMBO J 2022; 41:e110057. [PMID: 35285533 PMCID: PMC8982616 DOI: 10.15252/embj.2021110057] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 12/12/2022] Open
Abstract
Synaptic function crucially relies on the constant supply and removal of neuronal membranes. The morphological complexity of neurons poses a significant challenge for neuronal protein transport since the machineries for protein synthesis and degradation are mainly localized in the cell soma. In response to this unique challenge, local micro‐secretory systems have evolved that are adapted to the requirements of neuronal membrane protein proteostasis. However, our knowledge of how neuronal proteins are synthesized, trafficked to membranes, and eventually replaced and degraded remains scarce. Here, we review recent insights into membrane trafficking at synaptic sites and into the contribution of local organelles and micro‐secretory pathways to synaptic function. We describe the role of endoplasmic reticulum specializations in neurons, Golgi‐related organelles, and protein complexes like retromer in the synthesis and trafficking of synaptic transmembrane proteins. We discuss the contribution of autophagy and of proteasome‐mediated and endo‐lysosomal degradation to presynaptic proteostasis and synaptic function, as well as nondegradative roles of autophagosomes and lysosomes in signaling and synapse remodeling. We conclude that the complexity of neuronal cyto‐architecture necessitates long‐distance protein transport that combines degradation with signaling functions.
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Affiliation(s)
- Katarzyna M Grochowska
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
| | - Maria Andres‐Alonso
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
| | - Anna Karpova
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
- Center for Behavioral Brain Sciences Otto von Guericke University Magdeburg Germany
| | - Michael R Kreutz
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
- Center for Behavioral Brain Sciences Otto von Guericke University Magdeburg Germany
- German Center for Neurodegenerative Diseases (DZNE) Magdeburg Germany
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12
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Neyrinck K, Van Den Daele J, Vervliet T, De Smedt J, Wierda K, Nijs M, Vanbokhoven T, D'hondt A, Planque M, Fendt SM, Shih PY, Seibt F, Almenar JP, Kreir M, Kumar D, Broccoli V, Bultynck G, Ebneth A, Cabrera-Socorro A, Verfaillie C. SOX9-induced Generation of Functional Astrocytes Supporting Neuronal Maturation in an All-human System. Stem Cell Rev Rep 2021; 17:1855-1873. [PMID: 33982246 PMCID: PMC8553725 DOI: 10.1007/s12015-021-10179-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2021] [Indexed: 11/29/2022]
Abstract
Astrocytes, the main supportive cell type of the brain, show functional impairments upon ageing and in a broad spectrum of neurological disorders. Limited access to human astroglia for pre-clinical studies has been a major bottleneck delaying our understanding of their role in brain health and disease. We demonstrate here that functionally mature human astrocytes can be generated by SOX9 overexpression for 6 days in pluripotent stem cell (PSC)-derived neural progenitor cells. Inducible (i)SOX9-astrocytes display functional properties comparable to primary human astrocytes comprising glutamate uptake, induced calcium responses and cytokine/growth factor secretion. Importantly, electrophysiological properties of iNGN2-neurons co-cultured with iSOX9-astrocytes are indistinguishable from gold-standard murine primary cultures. The high yield, fast timing and the possibility to cryopreserve iSOX9-astrocytes without losing functional properties makes them suitable for scaled-up production for high-throughput analyses. Our findings represent a step forward to an all-human iPSC-derived neural model for drug development in neuroscience and towards the reduction of animal use in biomedical research.
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Affiliation(s)
- Katrien Neyrinck
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Johanna Van Den Daele
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Tim Vervliet
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jonathan De Smedt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Keimpe Wierda
- Electrophysiology Expert Unit, VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
| | - Melissa Nijs
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Tom Vanbokhoven
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Astrid D'hondt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Mélanie Planque
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Sarah-Maria Fendt
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Pei-Yu Shih
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Frederik Seibt
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Juan Pita Almenar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Mohamed Kreir
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Devesh Kumar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Vania Broccoli
- Division of Neuroscience, IRCCS, San Raffaele Scientific Hospital, 20132, Milan, Italy
- Institute of Neuroscience, National Research Council (CNR), 20129, Milan, Italy
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Andreas Ebneth
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | | | - Catherine Verfaillie
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
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13
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Regulation of longevity by depolarization-induced activation of PLC-β-IP 3R signaling in neurons. Proc Natl Acad Sci U S A 2021; 118:2004253118. [PMID: 33859040 PMCID: PMC8072327 DOI: 10.1073/pnas.2004253118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We demonstrate that depolarization of Drosophila glutamatergic neurons augmented inositol trisphosphate receptor (IP3R)-dependent release of endoplasmic reticulum (ER) Ca2+, which in turn potentiated mitochondrial Ca2+ uptake and ATP production. Perturbations that induced chronic depolarization, including the expression of neurodegeneration-related transgenes, led to the diversion of released ER Ca2+ into lysosomes and an attendant shortening of animal lifespan. Thus, genetic disruption of PLC-β–IP3R signaling or lysosomal Ca2+ uptake restored longevity in animals with chronically depolarized glutamatergic neurons. Our findings point to aberrant Ca2+ signaling between the ER and lysosomes as a mechanism by which hyperexcitable glutamatergic neurons shorten animal lifespan. Mitochondrial ATP production is a well-known regulator of neuronal excitability. The reciprocal influence of plasma-membrane potential on ATP production, however, remains poorly understood. Here, we describe a mechanism by which depolarized neurons elevate the somatic ATP/ADP ratio in Drosophila glutamatergic neurons. We show that depolarization increased phospholipase-Cβ (PLC-β) activity by promoting the association of the enzyme with its phosphoinositide substrate. Augmented PLC-β activity led to greater release of endoplasmic reticulum Ca2+ via the inositol trisphosphate receptor (IP3R), increased mitochondrial Ca2+ uptake, and promoted ATP synthesis. Perturbations that decoupled membrane potential from this mode of ATP synthesis led to untrammeled PLC-β–IP3R activation and a dramatic shortening of Drosophila lifespan. Upon investigating the underlying mechanisms, we found that increased sequestration of Ca2+ into endolysosomes was an intermediary in the regulation of lifespan by IP3Rs. Manipulations that either lowered PLC-β/IP3R abundance or attenuated endolysosomal Ca2+ overload restored animal longevity. Collectively, our findings demonstrate that depolarization-dependent regulation of PLC-β–IP3R signaling is required for modulation of the ATP/ADP ratio in healthy glutamatergic neurons, whereas hyperactivation of this axis in chronically depolarized glutamatergic neurons shortens animal lifespan by promoting endolysosomal Ca2+ overload.
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14
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Lysosomal Calcium Channels in Autophagy and Cancer. Cancers (Basel) 2021; 13:cancers13061299. [PMID: 33803964 PMCID: PMC8001254 DOI: 10.3390/cancers13061299] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Autophagy is a cellular self-eating process that uses lysosome, the waste disposal system of the cell, to degrade and recycle intracellular materials to maintain cellular homeostasis. Defects in autophagy are linked to a variety of pathological states, including cancer. Calcium is an important cellular messenger that regulates the survival of all animal cells. Alterations to calcium homoeostasis are associated with cancer. While it has long been considered as cellular recycling center, the lysosome is now widely known as an intracellular calcium store that regulates autophagy and cancer progression by releasing calcium via some ion channels residing in the lysosomal membrane. In this review, we summarize existing mechanisms of autophagy regulation by lysosomal calcium channels and their implications in cancer development. We hope to guide readers toward a more in-depth understanding of the importance of lysosomal calcium channels in cancer, and potentially facilitate the development of new therapeutics for some cancers. Abstract Ca2+ is pivotal intracellular messenger that coordinates multiple cell functions such as fertilization, growth, differentiation, and viability. Intracellular Ca2+ signaling is regulated by both extracellular Ca2+ entry and Ca2+ release from intracellular stores. Apart from working as the cellular recycling center, the lysosome has been increasingly recognized as a significant intracellular Ca2+ store that provides Ca2+ to regulate many cellular processes. The lysosome also talks to other organelles by releasing and taking up Ca2+. In lysosomal Ca2+-dependent processes, autophagy is particularly important, because it has been implicated in many human diseases including cancer. This review will discuss the major components of lysosomal Ca2+ stores and their roles in autophagy and human cancer progression.
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15
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Yuan Y, Kilpatrick BS, Gerndt S, Bracher F, Grimm C, Schapira AH, Patel S. The lysosomotrope GPN mobilises Ca 2+ from acidic organelles. J Cell Sci 2021; 134:jcs.256578. [PMID: 33602742 PMCID: PMC7972315 DOI: 10.1242/jcs.256578] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
Lysosomes are acidic Ca2+ stores often mobilised in conjunction with endoplasmic reticulum (ER) Ca2+ stores. Glycyl-L-phenylalanine 2-naphthylamide (GPN) is a widely used lysosomotropic agent that evokes cytosolic Ca2+ signals in many cells. However, whether these signals are the result of a primary action on lysosomes is unclear in light of recent evidence showing that GPN mediates direct ER Ca2+ release through changes in cytosolic pH. Here, we show that GPN evoked rapid increases in cytosolic pH but slower Ca2+ signals. NH4Cl evoked comparable changes in pH but failed to affect Ca2+. The V-type ATPase inhibitor, bafilomycin A1, increased lysosomal pH over a period of hours. Acute treatment modestly affected lysosomal pH and potentiated Ca2+ signals evoked by GPN. In contrast, chronic treatment led to more profound changes in luminal pH and selectively inhibited GPN action. GPN blocked Ca2+ responses evoked by the novel nicotinic acid adenine dinucleotide phosphate-like agonist, TPC2-A1-N. Therefore, GPN-evoked Ca2+ signals were better correlated with associated pH changes in the lysosome compared to the cytosol, and were coupled to lysosomal Ca2+ release. We conclude that Ca2+ signals evoked by GPN most likely derive from acidic organelles. Summary: Methods of releasing calcium from lysosomes are limited but characterization of the effects of GPN in primary cultured human fibroblasts confirmed that it probably targets acidic organelles.
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Affiliation(s)
- Yu Yuan
- Department of Cell and Developmental Biology, UCL, London WC1E 6BT, UK
| | | | - Susanne Gerndt
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians University, Munich 81377, Germany
| | - Franz Bracher
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians University, Munich 81377, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians University, Munich 80336, Germany
| | - Anthony H Schapira
- Department of Clinical Neurosciences, UCL Institute of Neurology, London NW3 2PF, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, UCL, London WC1E 6BT, UK
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16
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Morgan AJ, Galione A. Lysosomal agents inhibit store-operated Ca 2+ entry. J Cell Sci 2021; 134:224094. [PMID: 33328326 PMCID: PMC7860125 DOI: 10.1242/jcs.248658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 12/09/2020] [Indexed: 02/02/2023] Open
Abstract
Pharmacological manipulation of lysosome membrane integrity or ionic movements is a key strategy for probing lysosomal involvement in cellular processes. However, we have found an unexpected inhibition of store-operated Ca2+ entry (SOCE) by these agents. Dipeptides [glycyl-L-phenylalanine 2-naphthylamide (GPN) and L-leucyl-L-leucine methyl ester] that are inducers of lysosomal membrane permeabilization (LMP) uncoupled endoplasmic reticulum Ca2+-store depletion from SOCE by interfering with Stim1 oligomerization and/or Stim1 activation of Orai. Similarly, the K+/H+ ionophore, nigericin, that rapidly elevates lysosomal pH, also inhibited SOCE in a Stim1-dependent manner. In contrast, other strategies for manipulating lysosomes (bafilomycin A1, lysosomal re-positioning) had no effect upon SOCE. Finally, the effects of GPN on SOCE and Stim1 was reversed by a dynamin inhibitor, dynasore. Our data show that lysosomal agents not only release Ca2+ from stores but also uncouple this release from the normal recruitment of Ca2+ influx. Summary: Lysosomal agents uncouple ER Ca2+-release from store-operated Ca2+ entry, predominantly by inhibiting Stim1 oligomerization and its activation of Orai.
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Affiliation(s)
- 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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17
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Lagos-Cabré R, Ivanova A, Taylor CW. Ca 2+ Release by IP 3 Receptors Is Required to Orient the Mitotic Spindle. Cell Rep 2020; 33:108483. [PMID: 33326774 PMCID: PMC7758162 DOI: 10.1016/j.celrep.2020.108483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 09/23/2020] [Accepted: 11/13/2020] [Indexed: 11/30/2022] Open
Abstract
The mitotic spindle distributes chromosomes evenly to daughter cells during mitosis. The orientation of the spindle, guided by internal and external cues, determines the axis of cell division and thereby contributes to tissue morphogenesis. Progression through mitosis requires local Ca2+ signals at critical steps, and because store-operated Ca2+ entry is inhibited during mitosis, those signals probably require Ca2+ release through inositol 1,4,5-trisphosphate receptors (IP3Rs). In cells without IP3Rs, astral microtubules around the daughter centrosome are shorter than those at the mother centrosome, and the mitotic spindle fails to align with the substratum during metaphase. The misalignment is due to the spindle ineffectively detecting internal cues rather than a failure of cells to recognize the substratum. Expression of type 3 IP3R is sufficient to rescue spindle alignment, but only if the IP3R has a functional pore. We conclude that Ca2+ signals evoked by IP3Rs are required to orient the mitotic spindle. IP3 receptors are required for mitotic spindle orientation Only IP3 receptors with a functional channel restore spindle orientation Ca2+ release through IP3 receptors is required for spindle orientation
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Affiliation(s)
- Raul Lagos-Cabré
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Adelina Ivanova
- 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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18
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Atakpa-Adaji P, Thillaiappan NB, Taylor CW. IP3 receptors and their intimate liaisons. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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19
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Highton AJ, Diercks BP, Möckl F, Martrus G, Sauter J, Schmidt AH, Bunders MJ, Körner C, Guse AH, Altfeld M. High Metabolic Function and Resilience of NKG2A-Educated NK Cells. Front Immunol 2020; 11:559576. [PMID: 33101277 PMCID: PMC7554334 DOI: 10.3389/fimmu.2020.559576] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/20/2020] [Indexed: 12/19/2022] Open
Abstract
Natural killer (NK) cells are an important component of the innate immune system for the control of intracellular pathogens and cancer cells. NK cells demonstrate heterogeneous expression of inhibitory surface receptors. Signaling through these various receptors during NK cell development promotes functionality, referred to as NK cell education. Here we investigated the impact of education on NK cell metabolism through functional assessment of critical metabolic pathways and calcium signaling. Educated NK cells had an increased uptake of the metabolic substrates 2-NBDG, a fluorescent glucose analog, and BODIPY FL C16, a fluorescent palmitate, compared to uneducated NK cells. Comparison of NK cells educated via KIRs or NKG2A showed that NKG2A-educated NK cells were the main contributor to these differences in uptake of metabolites, and that NKG2A-educated NK cells were functionally more resilient in response to metabolic blockade of oxidative phosphorylation. Furthermore, NKG2A-educated NK cells exhibited higher peak calcium concentration following stimulation, indicating stronger signaling events taking place in these educated NK cells. These results demonstrate that cellular metabolism plays an important role in the functional differences observed between educated and uneducated NK cells, and show that NKG2A-educated NK cells remain more functionally competent than KIR-educated NK cells when oxidative phosphorylation is restricted. Understanding metabolic programming during NK cell education may unveil future targets to manipulate NK cell function for use in clinical settings, such as cancer therapies.
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Affiliation(s)
- Andrew J Highton
- Research Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Björn-Philipp Diercks
- The Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Franziska Möckl
- The Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gloria Martrus
- Research Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Jürgen Sauter
- Deutsche Knochenmarkspenderdatei (DKMS), Tübingen, Germany
| | | | - Madeleine J Bunders
- Research Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Christian Körner
- Research Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Andreas H Guse
- The Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marcus Altfeld
- Research Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
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20
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Lowin T, Tingting R, Zurmahr J, Classen T, Schneider M, Pongratz G. Cannabidiol (CBD): a killer for inflammatory rheumatoid arthritis synovial fibroblasts. Cell Death Dis 2020; 11:714. [PMID: 32873774 PMCID: PMC7463000 DOI: 10.1038/s41419-020-02892-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 12/18/2022]
Abstract
Cannabidiol (CBD) is a non-intoxicating phytocannabinoid from cannabis sativa that has demonstrated anti-inflammatory effects in several inflammatory conditions including arthritis. However, CBD binds to several receptors and enzymes and, therefore, its mode of action remains elusive. In this study, we show that CBD increases intracellular calcium levels, reduces cell viability and IL-6/IL-8/MMP-3 production of rheumatoid arthritis synovial fibroblasts (RASF). These effects were pronounced under inflammatory conditions by activating transient receptor potential ankyrin (TRPA1), and by opening of the mitochondrial permeability transition pore. Changes in intracellular calcium and cell viability were determined by using the fluorescent dyes Cal-520/PoPo3 together with cell titer blue and the luminescent dye RealTime-glo. Cell-based impedance measurements were conducted with the XCELLigence system and TRPA1 protein was detected by flow cytometry. Cytokine production was evaluated by ELISA. CBD reduced cell viability, proliferation, and IL-6/IL-8 production of RASF. Moreover, CBD increased intracellular calcium and uptake of the cationic viability dye PoPo3 in RASF, which was enhanced by pre-treatment with TNF. Concomitant incubation of CBD with the TRPA1 antagonist A967079 but not the TRPV1 antagonist capsazepine reduced the effects of CBD on calcium and PoPo3 uptake. In addition, an inhibitor of the mitochondrial permeability transition pore, cyclosporin A, also blocked the effects of CBD on cell viability and IL-8 production. PoPo3 uptake was inhibited by the voltage-dependent anion-selective channel inhibitor DIDS and Decynium-22, an inhibitor for all organic cation transporter isoforms. CBD increases intracellular calcium levels, reduces cell viability, and IL-6/IL-8/MMP-3 production of RASF by activating TRPA1 and mitochondrial targets. This effect was enhanced by pre-treatment with TNF suggesting that CBD preferentially targets activated, pro-inflammatory RASF. Thus, CBD possesses anti-arthritic activity and might ameliorate arthritis via targeting synovial fibroblasts under inflammatory conditions.
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Affiliation(s)
- Torsten Lowin
- Poliklinik, Funktionsbereich & Hiller Forschungszentrum für Rheumatologie, University Hospital Duesseldorf, D-40225, Duesseldorf, Germany.
| | - Ren Tingting
- Poliklinik, Funktionsbereich & Hiller Forschungszentrum für Rheumatologie, University Hospital Duesseldorf, D-40225, Duesseldorf, Germany
| | - Julia Zurmahr
- Poliklinik, Funktionsbereich & Hiller Forschungszentrum für Rheumatologie, University Hospital Duesseldorf, D-40225, Duesseldorf, Germany
| | - Tim Classen
- Klinik für Orthopädie/Orthopädische Rheumatologie, St. Elisabeth-Hospital Meerbusch-Lank, D-40668, Meerbusch, Germany
| | - Matthias Schneider
- Poliklinik, Funktionsbereich & Hiller Forschungszentrum für Rheumatologie, University Hospital Duesseldorf, D-40225, Duesseldorf, Germany
| | - Georg Pongratz
- Poliklinik, Funktionsbereich & Hiller Forschungszentrum für Rheumatologie, University Hospital Duesseldorf, D-40225, Duesseldorf, Germany
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Arlt E, Fraticelli M, Tsvilovskyy V, Nadolni W, Breit A, O'Neill TJ, Resenberger S, Wennemuth G, Wahl-Schott C, Biel M, Grimm C, Freichel M, Gudermann T, Klugbauer N, Boekhoff I, Zierler S. TPC1 deficiency or blockade augments systemic anaphylaxis and mast cell activity. Proc Natl Acad Sci U S A 2020; 117:18068-18078. [PMID: 32661165 PMCID: PMC7395440 DOI: 10.1073/pnas.1920122117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mast cells and basophils are main drivers of allergic reactions and anaphylaxis, for which prevalence is rapidly increasing. Activation of these cells leads to a tightly controlled release of inflammatory mediators stored in secretory granules. The release of these granules is dependent on intracellular calcium (Ca2+) signals. Ca2+ release from endolysosomal compartments is mediated via intracellular cation channels, such as two-pore channel (TPC) proteins. Here, we uncover a mechanism for how TPC1 regulates Ca2+ homeostasis and exocytosis in mast cells in vivo and ex vivo. Notably, in vivo TPC1 deficiency in mice leads to enhanced passive systemic anaphylaxis, reflected by increased drop in body temperature, most likely due to accelerated histamine-induced vasodilation. Ex vivo, mast cell-mediated histamine release and degranulation was augmented upon TPC1 inhibition, although mast cell numbers and size were diminished. Our results indicate an essential role of TPC1 in endolysosomal Ca2+ uptake and filling of endoplasmic reticulum Ca2+ stores, thereby regulating exocytosis in mast cells. Thus, pharmacological modulation of TPC1 might blaze a trail to develop new drugs against mast cell-related diseases, including allergic hypersensitivity.
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Affiliation(s)
- Elisabeth Arlt
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Marco Fraticelli
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | | | - Wiebke Nadolni
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Thomas J O'Neill
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Stefanie Resenberger
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Gunther Wennemuth
- Institute for Anatomy, University of Duisburg-Essen, 45147 Duisburg, Germany
| | | | - Martin Biel
- Department of Pharmacy, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Marc Freichel
- Institute of Pharmacology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany
| | - Norbert Klugbauer
- Institute for Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, Albert-Ludwigs-Universität, 79104 Freiburg, Germany
| | - Ingrid Boekhoff
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany;
| | - Susanna Zierler
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336 München, Germany;
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22
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Hermann J, Bender M, Schumacher D, Woo MS, Shaposhnykov A, Rosenkranz SC, Kuryshev V, Meier C, Guse AH, Friese MA, Freichel M, Tsvilovskyy V. Contribution of NAADP to Glutamate-Evoked Changes in Ca 2+ Homeostasis in Mouse Hippocampal Neurons. Front Cell Dev Biol 2020; 8:496. [PMID: 32676502 PMCID: PMC7333232 DOI: 10.3389/fcell.2020.00496] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger that evokes calcium release from intracellular organelles by the engagement of calcium release channels, including members of the Transient Receptor Potential (TRP) family, such as TRPML1, the (structurally) related Two Pore Channel type 1 (TPC1) and TPC2 channels as well as Ryanodine Receptors type 1 (RYR1; Guse, 2012). NAADP evokes calcium release from acidic calcium stores of many cell types (Guse, 2012), and NAADP-sensitive Ca2+ stores have been described in hippocampal neurons of the rat (Bak et al., 1999; McGuinness et al., 2007). Glutamate triggers Ca2+-mediated neuronal excitotoxicity in inflammation-induced neurodegenerative pathologies such as Multiple Sclerosis (MS; Friese et al., 2014), and when applied extracellularly to neurons glutamate can elevate NAADP levels in these cells. Accordingly, glutamate-evoked Ca2+ signals from intracellular organelles were inhibited by preventing organelle acidification (Pandey et al., 2009). Analysis of reported RNA sequencing experiments of cultured hippocampal neurons revealed the abundance of Mcoln1 (encoding TRPML1), Tpcn1, and Tpcn2 (encoding TPC1 and TPC2, respectively) as potential NAADP target channels in these cells. Transcripts encoding Ryr1 were not found in contrast to Ryr2 and Ryr3. To study the contribution of NAADP signaling to glutamate-evoked calcium transients in murine hippocampal neurons we used the NAADP antagonists Ned-19 (Naylor et al., 2009) and BZ194 (Dammermann et al., 2009). Our results show that both NAADP antagonists significantly reduce glutamate-evoked calcium transients. In addition to extracellular glutamate application, we studied synchronized calcium oscillations in the cells of the neuronal cultures evoked by addition of the GABAA receptor antagonist bicuculline. Pretreatment with Ned-19 (50 μM) or BZ194 (100 μM) led to an increase in the frequency of bicuculline-induced calcium oscillations at the cost of calcium transient amplitudes. Interestingly, Ned-19 triggered a rise in intracellular calcium concentrations 25 min after bicuculline stimulation, leading to the question whether NAADP acts as a neuroprotective messenger in hippocampal neurons. Taken together, our results are in agreement with the concept that NAADP signaling significantly contributes to glutamate evoked Ca2+ rise in hippocampal neurons and to the amplitude and frequency of synchronized Ca2+ oscillations triggered by spontaneous glutamate release events.
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Affiliation(s)
- Julia Hermann
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Melanie Bender
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Dagmar Schumacher
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Marcel S Woo
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Artem Shaposhnykov
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Sina C Rosenkranz
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Vladimir Kuryshev
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Chris Meier
- Organic Chemistry, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Andreas H Guse
- The Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Manuel A Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Volodymyr Tsvilovskyy
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
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23
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Lloyd-Evans E, Waller-Evans H. Lysosomal Ca 2+ Homeostasis and Signaling in Health and Disease. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035311. [PMID: 31653642 DOI: 10.1101/cshperspect.a035311] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Calcium (Ca2+) signaling is an essential process in all cells that is maintained by a plethora of channels, pumps, transporters, receptors, and intracellular Ca2+ sequestering stores. Changes in cytosolic Ca2+ concentration govern processes as far reaching as fertilization, cell growth, and motility through to cell death. In recent years, lysosomes have emerged as a major intracellular Ca2+ storage organelle with an increasing involvement in triggering or regulating cellular functions such as endocytosis, autophagy, and Ca2+ release from the endoplasmic reticulum. This review will summarize recent work in the area of lysosomal Ca2+ signaling and homeostasis, including newly identified functions, and the involvement of lysosome-derived Ca2+ signals in human disease. In addition, we explore recent controversies in the techniques used for measurement of lysosomal Ca2+ content.
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Affiliation(s)
- Emyr Lloyd-Evans
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Helen Waller-Evans
- Medicines Discovery Institute, Cardiff University, Cardiff CF10 3AT, United Kingdom
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24
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Abstract
Of the established Ca2+-mobilizing messengers, NAADP is arguably the most tantalizing. It is the most potent, often efficacious at low nanomolar concentrations, and its receptors undergo dramatic desensitization. Recent studies have identified a new class of calcium-release channel, the two-pore channels (TPCs), as the likely targets for NAADP regulation, even though the effect may be indirect. These channels localized at endolysosomes, where they mediate local Ca2+ release, and have highlighted a new role of acidic organelles as targets for messenger-evoked Ca2+ mobilization. Three distinct roles of TPCs have been identified. The first is to effect local Ca2+ release that may play a role in endolysosomal function including vesicular fusion and trafficking. The second is to trigger global calcium release by recruiting Ca2+-induced Ca2+-release (CICR) channels at lysosomal-endoplasmic reticulum (ER) junctions. The third is to regulate plasma membrane excitability by the targeting of Ca2+ release from appropriately positioned subplasma membrane stores to regulate plasma membrane Ca2+-activated channels. In this review, I discuss the role of nicotinic acid adenine nucleotide diphosphate (NAADP)-mediated Ca2+ release from endolysosomal stores as a widespread trigger for intracellular calcium signaling mechanisms, and how studies of TPCs are beginning to enhance our understanding of the central role of lysosomes in Ca2+ signaling.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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