1
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Moccia F, Morgan AJ. TPC2 gating: Trying to break the enigma code. Cell Calcium 2023; 116:102815. [PMID: 38980391 DOI: 10.1016/j.ceca.2023.102815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/17/2023] [Accepted: 10/17/2023] [Indexed: 07/10/2024]
Affiliation(s)
- Francesco Moccia
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia 27100, Italy.
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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2
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Gunaratne GS, Brailoiu E, Kumar S, Yuan Y, Slama JT, Walseth TF, Patel S, Marchant JS. Convergent activation of two-pore channels mediated by the NAADP-binding proteins JPT2 and LSM12. Sci Signal 2023; 16:eadg0485. [PMID: 37607218 PMCID: PMC10639087 DOI: 10.1126/scisignal.adg0485] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 07/27/2023] [Indexed: 08/24/2023]
Abstract
The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) evokes calcium ion (Ca2+) release from endosomes and lysosomes by activating two-pore channels (TPCs) on these organelles. Rather than directly binding to TPCs, NAADP associates with proteins that indirectly confer NAADP sensitivity to the TPC complex. We investigated whether and how the NAADP-binding proteins Jupiter microtubule-associated homolog 2 (JPT2) and like-Sm protein 12 (LSM12) contributed to NAADP-TPC-Ca2+ signaling in human cells. Biochemical and functional analyses revealed that recombinant JPT2 and LSM12 both bound to NAADP with high affinity and that endogenous JPT2 and LSM12 independently associated with TPC1 and TPC2. On the basis of knockout and rescue analyses, both NAADP-binding proteins were required to support NAADP-evoked Ca2+ signaling and contributed to endolysosomal trafficking of pseudotyped coronavirus particles. These data reveal that the NAADP-binding proteins JPT2 and LSM12 convergently regulate NAADP-evoked Ca2+ release and function through TPCs.
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Affiliation(s)
- Gihan S. Gunaratne
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Eugen Brailoiu
- Center for Substance Abuse Research and Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Sushil Kumar
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Yu Yuan
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - James T. Slama
- Department of Medicinal and Biological Chemistry, University of Toledo College of Pharmacy and Pharmaceutical Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA
| | - Timothy F. Walseth
- Department of Pharmacology, University of Minnesota Medical School, 312 Church St., Minneapolis, MN 55455, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Jonathan S. Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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3
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Abstract
The discovery of NAADP-evoked Ca2+ release in sea urchin eggs and then as a ubiquitous Ca2+ mobilizing messenger has introduced several novel paradigms to our understanding of Ca2+ signalling, not least in providing a link between cell stimulation and Ca2+ release from lysosomes and other acidic Ca2+ storage organelles. In addition, the hallmark concentration-response relationship of NAADP-mediated Ca2+ release, shaped by striking activation/desensitization mechanisms, influences its actions as an intracellular messenger. There has been recent progress in our understanding of the molecular mechanisms underlying NAADP-evoked Ca2+ release, such as the identification of the endo-lysosomal two-pore channel family of cation channels (TPCs) as their principal target and the identity of NAADP-binding proteins that complex with them. The NAADP/TPC signalling axis has gained recent prominence in pathophysiology for their roles in such disease processes as neurodegeneration, tumorigenesis and cellular viral entry.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK.
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Lora L Martucci
- Department of Pharmacology, University of Oxford, Oxford, UK
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4
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Russell T, Gangotia D, Barry G. Assessing the potential of repurposing ion channel inhibitors to treat emerging viral diseases and the role of this host factor in virus replication. Biomed Pharmacother 2022; 156:113850. [DOI: 10.1016/j.biopha.2022.113850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/25/2022] [Accepted: 10/06/2022] [Indexed: 12/03/2022] Open
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5
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Two-pore channels: going with the flows. Biochem Soc Trans 2022; 50:1143-1155. [PMID: 35959977 PMCID: PMC9444070 DOI: 10.1042/bst20220229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 11/26/2022]
Abstract
In recent years, our understanding of the structure, mechanisms and functions of the endo-lysosomal TPC (two-pore channel) family have grown apace. Gated by the second messengers, NAADP and PI(3,5)P2, TPCs are an integral part of fundamental signal-transduction pathways, but their array and plasticity of cation conductances (Na+, Ca2+, H+) allow them to variously signal electrically, osmotically or chemically. Their relative tissue- and organelle-selective distribution, together with agonist-selective ion permeabilities provides a rich palette from which extracellular stimuli can choose. TPCs are emerging as mediators of immunity, cancer, metabolism, viral infectivity and neurodegeneration as this short review attests.
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6
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Gunaratne GS, Marchant JS. The ins and outs of virus trafficking through acidic Ca 2+ stores. Cell Calcium 2022; 102:102528. [PMID: 35033909 PMCID: PMC8860173 DOI: 10.1016/j.ceca.2022.102528] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/20/2022]
Abstract
Many viruses exploit host-cell Ca2+ signaling processes throughout their life cycle. This is especially relevant for viruses that translocate through the endolysosomal system, where cellular infection is keyed to the microenvironment of these acidic Ca2+ stores and Ca2+-dependent trafficking pathways. As regulators of the endolysosomal ionic milieu and trafficking dynamics, two families of endolysosomal Ca2+-permeable cation channels - two pore channels (TPCs) and transient receptor potential mucolipins (TRPMLs) - have emerged as important host-cell factors in viral entry. Here, we review: (i) current evidence implicating Ca2+ signaling in viral translocation through the endolysosomal system, (ii) the roles of these ion channels in supporting cellular infection by different viruses, and (iii) areas for future research that will help define the potential of TPC and TRPML ligands as progressible antiviral agents.
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Affiliation(s)
- Gihan S Gunaratne
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee WI 53226, USA.
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee WI 53226, USA
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7
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Marchant JS, Gunaratne GS, Cai X, Slama JT, Patel S. NAADP-binding proteins find their identity. Trends Biochem Sci 2022; 47:235-249. [PMID: 34810081 PMCID: PMC8840967 DOI: 10.1016/j.tibs.2021.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 02/07/2023]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger that releases Ca2+ from endosomes and lysosomes by activating ion channels called two-pore channels (TPCs). However, no NAADP-binding site has been identified on TPCs. Rather, NAADP activates TPCs indirectly by engaging NAADP-binding proteins (NAADP-BPs) that form part of the TPC complex. After a decade of searching, two different NAADP-BPs were recently identified: Jupiter microtubule associated homolog 2 (JPT2) and like-Sm protein 12 (LSM12). These discoveries bridge the gap between NAADP generation and NAADP activation of TPCs, providing new opportunity to understand and manipulate the NAADP-signaling pathway. The unmasking of these NAADP-BPs will catalyze future studies to define the molecular choreography of NAADP action.
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Affiliation(s)
- Jonathan S. Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA,Correspondence: (J.S. Marchant) and (S. Patel)
| | - Gihan S. Gunaratne
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Xinjiang Cai
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - James T. Slama
- Department of Medicinal and Biological Chemistry, University of Toledo College of Pharmacy and Pharmaceutical Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
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8
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Identification of a dihydropyridine scaffold that blocks ryanodine receptors. iScience 2022; 25:103706. [PMID: 35059610 PMCID: PMC8760560 DOI: 10.1016/j.isci.2021.103706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/16/2021] [Accepted: 12/23/2021] [Indexed: 12/24/2022] Open
Abstract
Ryanodine receptors (RyRs) are large, intracellular ion channels that control Ca2+ release from the sarco/endoplasmic reticulum. Dysregulation of RyRs in skeletal muscle, heart, and brain has been implicated in various muscle pathologies, arrhythmia, heart failure, and Alzheimer's disease. Therefore, there is considerable interest in therapeutically targeting RyRs to normalize Ca2+ homeostasis in scenarios involving RyR dysfunction. Here, a simple invertebrate screening platform was used to discover new chemotypes targeting RyRs. The approach measured Ca2+ signals evoked by cyclic adenosine 5′-diphosphate ribose, a second messenger that sensitizes RyRs. From a 1,534-compound screen, FLI-06 (currently described as a Notch “inhibitor”) was identified as a potent blocker of RyR activity. Two closely related tyrosine kinase inhibitors that stimulate and inhibit Ca2+ release through RyRs were also resolved. Therefore, this simple screen yielded RyR scaffolds tractable for development and revealed an unexpected linkage between RyRs and trafficking events in the early secretory pathway. FLI-06 inhibits transport in the secretory pathway via an unknown mechanism An invertebrate screening platform revealed FLI-06 blocks intracellular Ca2+ release FLI-06 acts as a potent, cell-permeable ryanodine receptor (RyR) blocker The para-substituted dihydropyridine chemotype is a new scaffold for RyR modulation
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9
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Activation of endo-lysosomal two-pore channels by NAADP and PI(3,5)P2. Five things to know. Cell Calcium 2022; 103:102543. [PMID: 35123238 PMCID: PMC9552313 DOI: 10.1016/j.ceca.2022.102543] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 12/31/2022]
Abstract
Two-pore channels are ancient members of the voltage-gated ion channel superfamily that are expressed predominantly on acidic organelles such as endosomes and lysosomes. Here we review recent advances in understanding how TPCs are activated by their ligands and identify five salient features: (1) TPCs are Ca2+-permeable non-selective cation channels gated by NAADP. (2) NAADP activation is indirect through associated NAADP receptors. (3) TPCs are also Na+-selective channels gated by PI(3,5)P2. (4) PI(3,5)P2 activation is direct through a structurally-resolved binding site. (5) TPCs switch their ion selectivity in an agonist-dependent manner.
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10
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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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11
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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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12
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Gunaratne GS, Brailoiu E, He S, Unterwald EM, Patel S, Slama JT, Walseth TF, Marchant JS. Essential requirement for JPT2 in NAADP-evoked Ca 2+ signaling. Sci Signal 2021; 14:14/675/eabd5605. [PMID: 33758061 DOI: 10.1126/scisignal.abd5605] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger that releases Ca2+ from acidic organelles through the activation of two-pore channels (TPCs) to regulate endolysosomal trafficking events. NAADP action is mediated by NAADP-binding protein(s) of unknown identity that confer NAADP sensitivity to TPCs. Here, we used a "clickable" NAADP-based photoprobe to isolate human NAADP-binding proteins and identified Jupiter microtubule-associated homolog 2 (JPT2) as a TPC accessory protein required for endogenous NAADP-evoked Ca2+ signaling. JPT2 was also required for the translocation of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus through the endolysosomal system. Thus, JPT2 is a component of the NAADP receptor complex that is essential for TPC-dependent Ca2+ signaling and control of coronaviral entry.
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Affiliation(s)
- Gihan S Gunaratne
- Department of Pharmacology, University of Minnesota Medical School, 312 Church Street, Minneapolis, MN 55455, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Eugen Brailoiu
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shijun He
- Department of Medicinal and Biological Chemistry, University of Toledo College of Pharmacy and Pharmaceutical Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA
| | - Ellen M Unterwald
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - James T Slama
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota Medical School, 312 Church Street, Minneapolis, MN 55455, USA
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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13
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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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14
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Moccia F, Negri S, Faris P, Perna A, De Luca A, Soda T, Berra-Romani R, Guerra G. Targeting Endolysosomal Two-Pore Channels to Treat Cardiovascular Disorders in the Novel COronaVIrus Disease 2019. Front Physiol 2021; 12:629119. [PMID: 33574769 PMCID: PMC7870486 DOI: 10.3389/fphys.2021.629119] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/07/2021] [Indexed: 12/15/2022] Open
Abstract
Emerging evidence hints in favor of a life-threatening link between severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and the cardiovascular system. SARS-CoV-2 may result in dramatic cardiovascular complications, whereas the severity of COronaVIrus Disease 2019 (COVID-19) and the incidence of fatalities tend to increase in patients with pre-existing cardiovascular complications. SARS-CoV-2 is internalized into the host cells by endocytosis and may then escape the endolysosomal system via endosomes. Two-pore channels drive endolysosomal trafficking through the release of endolysosomal Ca2+. Recent evidence suggested that the pharmacological inhibition of TPCs prevents Ebola virus and Middle East Respiratory Syndrome COronaVirus (MERS-CoV) entry into host cells. In this perspective, we briefly summarize the biophysical and pharmacological features of TPCs, illustrate their emerging role in the cardiovascular system, and finally present them as a reliable target to treat cardiovascular complications in COVID-19 patients.
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Affiliation(s)
- Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Sharon Negri
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Pawan Faris
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Angelica Perna
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, Campobasso, Italy
| | - Antonio De Luca
- Section of Human Anatomy, Department of Mental and Physical Health and Preventive Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Teresa Soda
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Roberto Berra-Romani
- School of Medicine, Department of Biomedicine, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Germano Guerra
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, Campobasso, Italy
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15
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Vassileva K, Marsh M, Patel S. Two-pore channels as master regulators of membrane trafficking and endocytic well-being. CURRENT OPINION IN PHYSIOLOGY 2020; 17:163-168. [PMID: 32838099 PMCID: PMC7426208 DOI: 10.1016/j.cophys.2020.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Two-pore channels (TPCs) are a ubiquitous class of Ca2+- and Na+-permeable ion channels expressed within the endo-lysosomal system. They have emerged as central regulators of a wide array of physiological processes intimately linked to information processing. In this short review, we highlight how molecular and chemical strategies have uncovered multiple roles for TPCs in regulating various aspects of endo-lysosomal trafficking associated with disease. We summarise advances in the identification of new small molecules to pharmacologically target TPCs for medical benefit. Lastly, we discuss possible underpinning molecular mechanism(s) that translate TPC-mediated ionic fluxes to function.
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Affiliation(s)
- Kristin Vassileva
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
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16
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Moccia F, Gerbino A, Lionetti V, Miragoli M, Munaron LM, Pagliaro P, Pasqua T, Penna C, Rocca C, Samaja M, Angelone T. COVID-19-associated cardiovascular morbidity in older adults: a position paper from the Italian Society of Cardiovascular Researches. GeroScience 2020; 42:1021-1049. [PMID: 32430627 PMCID: PMC7237344 DOI: 10.1007/s11357-020-00198-w] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 04/28/2020] [Indexed: 01/08/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects host cells following binding with the cell surface ACE2 receptors, thereby leading to coronavirus disease 2019 (COVID-19). SARS-CoV-2 causes viral pneumonia with additional extrapulmonary manifestations and major complications, including acute myocardial injury, arrhythmia, and shock mainly in elderly patients. Furthermore, patients with existing cardiovascular comorbidities, such as hypertension and coronary heart disease, have a worse clinical outcome following contraction of the viral illness. A striking feature of COVID-19 pandemics is the high incidence of fatalities in advanced aged patients: this might be due to the prevalence of frailty and cardiovascular disease increase with age due to endothelial dysfunction and loss of endogenous cardioprotective mechanisms. Although experimental evidence on this topic is still at its infancy, the aim of this position paper is to hypothesize and discuss more suggestive cellular and molecular mechanisms whereby SARS-CoV-2 may lead to detrimental consequences to the cardiovascular system. We will focus on aging, cytokine storm, NLRP3/inflammasome, hypoxemia, and air pollution, which is an emerging cardiovascular risk factor associated with rapid urbanization and globalization. We will finally discuss the impact of clinically available CV drugs on the clinical course of COVID-19 patients. Understanding the role played by SARS-CoV2 on the CV system is indeed mandatory to get further insights into COVID-19 pathogenesis and to design a therapeutic strategy of cardio-protection for frail patients.
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Affiliation(s)
- F Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - A Gerbino
- CNR-Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
| | - V Lionetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.
- UOS Anesthesiology and Intensive Care Medicine, Fondazione Toscana G. Monasterio, Pisa, Italy.
| | - M Miragoli
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - L M Munaron
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - P Pagliaro
- Clinical and Biological Sciences Department, University of Turin, Orbassano, Turin, Italy.
| | - T Pasqua
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Arcavacata di Rende, CS, Italy
| | - C Penna
- Clinical and Biological Sciences Department, University of Turin, Orbassano, Turin, Italy
| | - C Rocca
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Arcavacata di Rende, CS, Italy
| | - M Samaja
- Department of Health Science, University of Milano, Milan, Italy
| | - T Angelone
- Laboratory of Cellular and Molecular Cardiovascular Patho-physiology, Department of Biology, E. and E.S., University of Calabria, Arcavacata di Rende, CS, Italy
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17
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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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18
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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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19
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Krogsaeter EK, Biel M, Wahl-Schott C, Grimm C. The protein interaction networks of mucolipins and two-pore channels. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:1111-1123. [PMID: 30395881 PMCID: PMC7111325 DOI: 10.1016/j.bbamcr.2018.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The endolysosomal, non-selective cation channels, two-pore channels (TPCs) and mucolipins (TRPMLs), regulate intracellular membrane dynamics and autophagy. While partially compensatory for each other, isoform-specific intracellular distribution, cell-type expression patterns, and regulatory mechanisms suggest different channel isoforms confer distinct properties to the cell. SCOPE OF REVIEW Briefly, established TPC/TRPML functions and interaction partners ('interactomes') are discussed. Novel TRPML3 interactors are shown, and a meta-analysis of experimentally obtained channel interactomes conducted. Accordingly, interactomes are compared and contrasted, and subsequently described in detail for TPC1, TPC2, TRPML1, and TRPML3. MAJOR CONCLUSIONS TPC interactomes are well-defined, encompassing intracellular membrane organisation proteins. TRPML interactomes are varied, encompassing cardiac contractility- and chaperone-mediated autophagy proteins, alongside regulators of intercellular signalling. GENERAL SIGNIFICANCE Comprising recently proposed targets to treat cancers, infections, metabolic disease and neurodegeneration, the advancement of TPC/TRPML understanding is of considerable importance. This review proposes novel directions elucidating TPC/TRPML relevance in health and disease. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Einar K Krogsaeter
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Munich (LMU) Nussbaumstrasse 26, 80336 Munich
| | - Martin Biel
- Department of Pharmacy - Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Germany
| | - Christian Wahl-Schott
- Hannover Medical School, Institute for Neurophysiology, OE 4230, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Christian Grimm
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Munich (LMU) Nussbaumstrasse 26, 80336 Munich.
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20
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Penny CJ, Vassileva K, Jha A, Yuan Y, Chee X, Yates E, Mazzon M, Kilpatrick BS, Muallem S, Marsh M, Rahman T, Patel S. Mining of Ebola virus entry inhibitors identifies approved drugs as two-pore channel pore blockers. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:1151-1161. [PMID: 30408544 PMCID: PMC7114365 DOI: 10.1016/j.bbamcr.2018.10.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 01/04/2023]
Abstract
Two-pore channels (TPCs) are Ca2+-permeable ion channels localised to the endo-lysosomal system where they regulate trafficking of various cargoes including viruses. As a result, TPCs are emerging as important drug targets. However, their pharmacology is ill-defined. There are no approved drugs to target them. And their mechanism of ligand activation is largely unknown. Here, we identify a number of FDA-approved drugs as TPC pore blockers. Using a model of the pore of human TPC2 based on recent structures of mammalian TPCs, we virtually screened a database of ~1500 approved drugs. Because TPCs have recently emerged as novel host factors for Ebola virus entry, we reasoned that Ebola virus entry inhibitors may exert their effects through inhibition of TPCs. Cross-referencing hits from the TPC virtual screen with two recent high throughput anti-Ebola screens yielded approved drugs targeting dopamine and estrogen receptors as common hits. These compounds inhibited endogenous NAADP-evoked Ca2+ release from sea urchin egg homogenates, NAADP-mediated channel activity of TPC2 re-routed to the plasma membrane, and PI(3,5)P2-mediated channel activity of TPC2 expressed in enlarged lysosomes. Mechanistically, single channel analyses showed that the drugs reduced mean open time consistent with a direct action on the pore. Functionally, drug potency in blocking TPC2 activity correlated with inhibition of Ebola virus-like particle entry. Our results expand TPC pharmacology through the identification of approved drugs as novel blockers, support a role for TPCs in Ebola virus entry, and provide insight into the mechanisms underlying channel regulation. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Christopher J Penny
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Kristin Vassileva
- Department of Cell and Developmental Biology, University College London, London, UK; MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Archana Jha
- Epithelial Signaling and Transport Section, National Institute of Dental Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yu Yuan
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Xavier Chee
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Elizabeth Yates
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Michela Mazzon
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Bethan S Kilpatrick
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK.
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21
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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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22
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5-Azido-8-ethynyl-NAADP: A bifunctional, clickable photoaffinity probe for the identification of NAADP receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1180-1188. [PMID: 30521871 DOI: 10.1016/j.bbamcr.2018.11.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 12/22/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate is an evolutionarily conserved second messenger, which mobilizes Ca2+ from acidic stores. The molecular identity of the NAADP receptor has yet to be defined. In pursuit of isolating and identifying NAADP-binding proteins, we synthesized and characterized a bifunctional probe that incorporates both a photoactivatable crosslinking azido moiety at the 5-position of the nicotinic ring and a 'clickable' ethynyl moiety to the 8-adenosyl position in NAADP. Microinjection of this 5N3-8-ethynyl-NAADP into cultured U2OS cells induced robust Ca2+ responses. Higher concentrations of 5N3-8-ethynyl were required to elicit Ca2+ release or displace 32P-NAADP in radioligand binding experiments in sea urchin egg homogenates. In human cell extracts, incubation of 32P-5N3-8-ethynyl-NAADP followed by UV irradiation resulted in selective labeling of 23 kDa and 35 kDa proteins and photolabeling of these proteins was prevented when incubated in the presence of unlabeled NAADP. Compared to the monofunctional 32P-5N3-NAADP, the clickable 32P-5N3-8-ethynyl-NAADP demonstrated less labeling of the 23 kDa and 35 kDa proteins (~3-fold) but provided an opportunity for further enrichment through the 'clickable' ethynyl moiety. No proteins were specifically labeled by 32P-5N3-8-ethynyl-NAADP in sea urchin egg homogenate. These experiments demonstrate that 5N3-8-ethynyl-NAADP is biologically active and selectively labels putative NAADP-binding proteins in mammalian systems, evidencing a 'bifunctional' probe with utility for isolating NAADP-binding proteins.
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23
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Gunaratne GS, Johns ME, Hintz HM, Walseth TF, Marchant JS. A screening campaign in sea urchin egg homogenate as a platform for discovering modulators of NAADP-dependent Ca 2+ signaling in human cells. Cell Calcium 2018; 75:42-52. [PMID: 30145428 PMCID: PMC6286156 DOI: 10.1016/j.ceca.2018.08.002] [Citation(s) in RCA: 22] [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] [Received: 07/09/2018] [Revised: 08/07/2018] [Accepted: 08/07/2018] [Indexed: 12/16/2022]
Abstract
The Ca2+ mobilizing second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) regulates intracellular trafficking events, including translocation of certain enveloped viruses through the endolysosomal system. Targeting NAADP-evoked Ca2+ signaling may therefore be an effective strategy for discovering novel antivirals as well as therapeutics for other disorders. To aid discovery of novel scaffolds that modulate NAADP-evoked Ca2+ signaling in human cells, we have investigated the potential of using the sea urchin egg homogenate system for a screening campaign. Known pharmacological inhibitors of NAADP-evoked Ca2+ release (but not cADPR- or IP3-evoked Ca2+ release) in this invertebrate system strongly correlated with inhibition of MERS-pseudovirus infectivity in a human cell line. A primary screen of 1534 compounds yielded eighteen 'hits' exhibiting >80% inhibition of NAADP-evoked Ca2+ release. A validation pipeline for these candidates yielded seven drugs that inhibited NAADP-evoked Ca2+ release without depleting acidic Ca2+ stores in a human cell line. These candidates displayed a similar penetrance of inhibition in both the sea urchin system and the human cell line, and the extent of inhibition of NAADP-evoked Ca2+ signals correlated well with observed inhibition of infectivity of a Middle East Respiratory syndrome coronavirus (MERS-CoV) pseudovirus. These experiments support the potential of this simple, homogenate system for screening campaigns to discover modulators of NAADP, cADPR and IP3-dependent Ca2+ signaling with potential therapeutic value.
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Affiliation(s)
- Gihan S Gunaratne
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Malcolm E Johns
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Hallie M Hintz
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee WI 53226, USA.
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24
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NAADP-dependent Ca 2+ signaling regulates Middle East respiratory syndrome-coronavirus pseudovirus translocation through the endolysosomal system. Cell Calcium 2018; 75:30-41. [PMID: 30121440 PMCID: PMC6251489 DOI: 10.1016/j.ceca.2018.08.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/07/2018] [Accepted: 08/07/2018] [Indexed: 11/09/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) releases Ca2+ from acidic organelles. Middle East Respiratory Syndrome coronavirus (MERS-CoV) traffics through host-cell acidic organelles. Blockers of NAADP action inhibited pseudotyped MERS-CoV infectivity. Knockdown of two-pore channels (TPCs), a target of NAADP, also blocked MERS-CoV infectivity.
Middle East Respiratory Syndrome coronavirus (MERS-CoV) infections are associated with a significant mortality rate, and existing drugs show poor efficacy. Identifying novel targets/pathways required for MERS infectivity is therefore important for developing novel therapeutics. As an enveloped virus, translocation through the endolysosomal system provides one pathway for cellular entry of MERS-CoV. In this context, Ca2+-permeable channels within the endolysosomal system regulate both the luminal environment and trafficking events, meriting investigation of their role in regulating processing and trafficking of MERS-CoV. Knockdown of endogenous two-pore channels (TPCs), targets for the Ca2+ mobilizing second messenger NAADP, impaired infectivity in a MERS-CoV spike pseudovirus particle translocation assay. This effect was selective as knockdown of the lysosomal cation channel mucolipin-1 (TRPML1) was without effect. Pharmacological inhibition of NAADP-evoked Ca2+ release using several bisbenzylisoquinoline alkaloids also blocked MERS pseudovirus translocation. Knockdown of TPC1 (biased endosomally) or TPC2 (biased lysosomally) decreased the activity of furin, a protease which facilitates MERS fusion with cellular membranes. Pharmacological or genetic inhibition of TPC1 activity also inhibited endosomal motility impairing pseudovirus progression through the endolysosomal system. Overall, these data support a selective, spatially autonomous role for TPCs within acidic organelles to support MERS-CoV translocation.
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