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Zhou D, Eraslan Z, Miller D, Taylor I, You J, Grondin SJ, Vega M, Manga P, Goff PS, Sviderskaya EV, Gross SS, Chen Q, Zippin JH. Two-pore channel 2 is required for soluble adenylyl cyclase-dependent regulation of melanosomal pH and melanin synthesis. Pigment Cell Melanoma Res 2024. [PMID: 38844435 DOI: 10.1111/pcmr.13177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 04/25/2024] [Accepted: 05/24/2024] [Indexed: 07/17/2024]
Abstract
Melanosomal pH is important for the synthesis of melanin as the rate-limiting enzyme, tyrosinase, is very pH-sensitive. The soluble adenylyl cyclase (sAC) signaling pathway was recently identified as a regulator of melanosomal pH in melanocytes; however, the melanosomal proteins critical for sAC-dependent regulation of melanosomal pH were undefined. We now systematically examine four well-characterized melanosomal membrane proteins to determine whether any of them are required for sAC-dependent regulation of melanosomal pH. We find that OA1, OCA2, and SLC45A2 are dispensable for sAC-dependent regulation of melanosomal pH. In contrast, TPC2 activity is required for sAC-dependent regulation of melanosomal pH and melanin synthesis. In addition, activation of TPC2 by NAADP-AM rescues melanosomal pH alkalinization and reduces melanin synthesis following pharmacologic or genetic inhibition of sAC signaling. These studies establish TPC2 as a critical melanosomal protein for sAC-dependent regulation of melanosomal pH and pigmentation.
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Affiliation(s)
- Dalee Zhou
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Zuhal Eraslan
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Dawson Miller
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Isobel Taylor
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Jaewon You
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Samuel J Grondin
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Martha Vega
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, USA
| | - Prashiela Manga
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, USA
| | - Philip S Goff
- Cell Biology Research Section, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Elena V Sviderskaya
- Cell Biology Research Section, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Steven S Gross
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Qiuying Chen
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Jonathan H Zippin
- Department of Dermatology, Weill Cornell Medical College of Cornell University, New York, New York, USA
- Department of Pharmacology, Weill Cornell Medical College of Cornell University, New York, New York, USA
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2
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Nguyen HT, Wiederkehr A, Wollheim CB, Park KS. Regulation of autophagy by perilysosomal calcium: a new player in β-cell lipotoxicity. Exp Mol Med 2024; 56:273-288. [PMID: 38297165 PMCID: PMC10907728 DOI: 10.1038/s12276-024-01161-x] [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: 05/03/2023] [Revised: 10/16/2023] [Accepted: 11/09/2023] [Indexed: 02/02/2024] Open
Abstract
Autophagy is an essential quality control mechanism for maintaining organellar functions in eukaryotic cells. Defective autophagy in pancreatic beta cells has been shown to be involved in the progression of diabetes through impaired insulin secretion under glucolipotoxic stress. The underlying mechanism reveals the pathologic role of the hyperactivation of mechanistic target of rapamycin (mTOR), which inhibits lysosomal biogenesis and autophagic processes. Moreover, accumulating evidence suggests that oxidative stress induces Ca2+ depletion in the endoplasmic reticulum (ER) and cytosolic Ca2+ overload, which may contribute to mTOR activation in perilysosomal microdomains, leading to autophagic defects and β-cell failure due to lipotoxicity. This review delineates the antagonistic regulation of autophagic flux by mTOR and AMP-dependent protein kinase (AMPK) at the lysosomal membrane, and both of these molecules could be activated by perilysosomal calcium signaling. However, aberrant and persistent Ca2+ elevation upon lipotoxic stress increases mTOR activity and suppresses autophagy. Therefore, normalization of autophagy is an attractive therapeutic strategy for patients with β-cell failure and diabetes.
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Affiliation(s)
- Ha Thu Nguyen
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Korea
| | | | - Claes B Wollheim
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Korea.
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Korea.
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3
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Mu-U-Min RBA, Diane A, Allouch A, Al-Siddiqi HH. Ca 2+-Mediated Signaling Pathways: A Promising Target for the Successful Generation of Mature and Functional Stem Cell-Derived Pancreatic Beta Cells In Vitro. Biomedicines 2023; 11:1577. [PMID: 37371672 DOI: 10.3390/biomedicines11061577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Diabetes mellitus is a chronic disease affecting over 500 million adults globally and is mainly categorized as type 1 diabetes mellitus (T1DM), where pancreatic beta cells are destroyed, and type 2 diabetes mellitus (T2DM), characterized by beta cell dysfunction. This review highlights the importance of the divalent cation calcium (Ca2+) and its associated signaling pathways in the proper functioning of beta cells and underlines the effects of Ca2+ dysfunction on beta cell function and its implications for the onset of diabetes. Great interest and promise are held by human pluripotent stem cell (hPSC) technology to generate functional pancreatic beta cells from diabetic patient-derived stem cells to replace the dysfunctional cells, thereby compensating for insulin deficiency and reducing the comorbidities of the disease and its associated financial and social burden on the patient and society. Beta-like cells generated by most current differentiation protocols have blunted functionality compared to their adult human counterparts. The Ca2+ dynamics in stem cell-derived beta-like cells and adult beta cells are summarized in this review, revealing the importance of proper Ca2+ homeostasis in beta-cell function. Consequently, the importance of targeting Ca2+ function in differentiation protocols is suggested to improve current strategies to use hPSCs to generate mature and functional beta-like cells with a comparable glucose-stimulated insulin secretion (GSIS) profile to adult beta cells.
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Affiliation(s)
- Razik Bin Abdul Mu-U-Min
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Abdoulaye Diane
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Asma Allouch
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Heba H Al-Siddiqi
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
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4
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Wang Q, Zhu MX. NAADP-Dependent TPC Current. Handb Exp Pharmacol 2023; 278:35-56. [PMID: 35902437 DOI: 10.1007/164_2022_606] [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, TPC1 and TPC2, are Ca2+- and Na+-permeable cation channels expressed on the membranes of endosomes and lysosomes in nearly all mammalian cells. These channels have been implicated in Ca2+ signaling initiated from the endolysosomes, vesicular trafficking, cellular metabolism, macropinocytosis, and viral infection. Although TPCs have been shown to mediate Ca2+ release from acidic organelles in response to NAADP (nicotinic acid adenine dinucleotide phosphate), the most potent Ca2+ mobilizing messenger, questions remain whether NAADP is a direct ligand of these channels. In whole-endolysosomal patch clamp recordings, it has been difficult to detect NAADP-evoked currents in vacuoles that expressed TPC1 or TPC2, while PI(3,5)P2 (phosphatidylinositol 3,5-bisphosphate) activated a highly Na+-selective current under the same experimental configuration. In this chapter, we summarize recent progress in this area and provide our observations on NAADP-elicited TPC2 currents from enlarged endolysosomes as well as their possible relationships with the currents evoked by PI(3,5)P2. We propose that TPCs are channels dually regulated by PI(3,5)P2 and NAADP in an interdependent manner and the two endogenous ligands may have both distinguished and cooperative roles.
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Affiliation(s)
- Qiaochu Wang
- Beijing Children's Hospital, Capital Medical University, Beijing, China
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA.
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5
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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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6
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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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7
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Martucci LL, Cancela JM. Neurophysiological functions and pharmacological tools of acidic and non-acidic Ca2+ stores. Cell Calcium 2022; 104:102582. [DOI: 10.1016/j.ceca.2022.102582] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/07/2022] [Accepted: 03/23/2022] [Indexed: 02/08/2023]
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8
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Krogsaeter E, Rosato AS, Grimm C. TRPMLs and TPCs: targets for lysosomal storage and neurodegenerative disease therapy? Cell Calcium 2022; 103:102553. [DOI: 10.1016/j.ceca.2022.102553] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/04/2022] [Accepted: 02/04/2022] [Indexed: 12/25/2022]
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9
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Jin X, Zhang Y, Alharbi A, Hanbashi A, Alhoshani A, Parrington J. Targeting Two-Pore Channels: Current Progress and Future Challenges. Trends Pharmacol Sci 2021; 41:582-594. [PMID: 32679067 PMCID: PMC7365084 DOI: 10.1016/j.tips.2020.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/04/2020] [Accepted: 06/04/2020] [Indexed: 12/19/2022]
Abstract
Two-pore channels (TPCs) are cation-permeable channels located on endolysosomal membranes and important mediators of intracellular Ca2+ signalling. TPCs are involved in various pathophysiological processes, including cell growth and development, metabolism, and cancer progression. Most studies of TPCs have used TPC–/– cell or whole-animal models, or Ned-19, an indirect inhibitor. The TPC activation mechanism remains controversial, which has made it difficult to develop selective modulators. Recent studies of TPC structure and their interactomes are aiding the development of direct pharmacological modulators. This process is still in its infancy, but will facilitate future research and TPC targeting for therapeutical purposes. Here, we review the progress of current research into TPCs, including recent insights into their structures, functional roles, mechanisms of activation, and pharmacological modulators. Two-pore channel (TPC)-mediated endolysosomal Ca2+ signalling regulates a variety of processes, including cell proliferation, differentiation, metabolism, viral infection, and cardiac function. Despite the well-established model that TPCs are Ca2+-selective channels indirectly activated by nicotinic acid adenine dinucleotide phosphate (NAADP), it has also been proposed that TPCs as Na+ channels are activated directly by phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. 3D structures of mouse TPC1 and human TPC2 were recently determined, which made it possible for structure-based virtual screening methods to identify pharmacological modulators of TPC. Recent identification by high-throughput screens of pharmacological modulators that target TPCs will help reveal the molecular mechanisms underlying the role of endolysosomal Ca2+ signalling in different pathophysiological processes, and to develop new therapeutics.
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Affiliation(s)
- Xuhui Jin
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Yuxuan Zhang
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Abeer Alharbi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ali Hanbashi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ali Alhoshani
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, PO Box 2457, Riyadh 11454, Kingdom of Saudi Arabia
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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10
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Glucose and NAADP trigger elementary intracellular β-cell Ca 2+ signals. Sci Rep 2021; 11:10714. [PMID: 34021189 PMCID: PMC8140081 DOI: 10.1038/s41598-021-88906-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 04/15/2021] [Indexed: 11/12/2022] Open
Abstract
Pancreatic β-cells release insulin upon a rise in blood glucose. The precise mechanisms of stimulus-secretion coupling, and its failure in Diabetes Mellitus Type 2, remain to be elucidated. The consensus model, as well as a class of currently prescribed anti-diabetic drugs, are based around the observation that glucose-evoked ATP production in β-cells leads to closure of cell membrane ATP-gated potassium (KATP) channels, plasma membrane depolarisation, Ca2+ influx, and finally the exocytosis of insulin granules. However, it has been demonstrated by the inactivation of this pathway using genetic and pharmacological means that closure of the KATP channel alone may not be sufficient to explain all β-cell responses to glucose elevation. We have previously proposed that NAADP-evoked Ca2+ release is an important step in stimulus-secretion coupling in pancreatic β-cells. Here we show using total internal reflection fluorescence (TIRF) microscopy that glucose as well as the Ca2+ mobilising messenger nicotinic acid adenine dinucleotide phosphate (NAADP), known to operate in β-cells, lead to highly localised elementary intracellular Ca2+ signals. These were found to be obscured by measurements of global Ca2+ signals and the action of powerful SERCA-based sequestration mechanisms at the endoplasmic reticulum (ER). Building on our previous work demonstrating that NAADP-evoked Ca2+ release is an important step in stimulus-secretion coupling in pancreatic β-cells, we provide here the first demonstration of elementary Ca2+ signals in response to NAADP, whose occurrence was previously suspected. Optical quantal analysis of these events reveals a unitary event amplitude equivalent to that of known elementary Ca2+ signalling events, inositol trisphosphate (IP3) receptor mediated blips, and ryanodine receptor mediated quarks. We propose that a mechanism based on these highly localised intracellular Ca2+ signalling events mediated by NAADP may initially operate in β-cells when they respond to elevations in blood glucose.
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11
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Abstract
Lysosomal calcium is emerging as a modulator of autophagy and lysosomal compartment, an obligatory partner to complete the autophagic pathway. A variety of specific signals such as nutrient deprivation or oxidative stress can trigger lysosomal calcium-mediated nuclear translocation of the transcription factor EB (TFEB), a master regulator of global lysosomal function. Also, lysosomal calcium can promote the formation of autophagosome vesicles (AVs) by a mechanism that requires the production of the phosphoinositide PI3P by the VPS34 autophagic complex and the activation of the energy-sensing kinase AMPK. Additionally, lysosomal calcium plays a role in membrane fusion and fission events involved in cellular processes such as endocytic maturation, autophagosome-lysosome fusion, lysosomal exocytosis, and lysosomal reformation upon autophagy completion. Lysosomal calcium-dependent functions are defective in cellular and animal models of the non-selective cation channel TRPML1, whose mutations in humans cause the neurodegenerative lysosomal storage disease mucolipidosis type IV (MLIV). Lysosomal calcium is not only acting as a positive regulator of autophagy, but it is also responsible for turning-off this process through the reactivation of the mTOR kinase during prolonged starvation. More recently, it has been described the role of lysosomal calcium on an elegant sequence of intracellular signaling events such as membrane repair, lysophagy, and lysosomal biogenesis upon the induction of different grades of lysosomal membrane damage. Here, we will discuss these novel findings that re-define the importance of the lysosome and lysosomal calcium signaling at regulating cellular metabolism.
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12
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Morgan AJ, Davis LC, Galione A. Choreographing endo-lysosomal Ca 2+ throughout the life of a phagosome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119040. [PMID: 33872669 DOI: 10.1016/j.bbamcr.2021.119040] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 12/20/2022]
Abstract
The emergence of endo-lysosomes as ubiquitous Ca2+ stores with their unique cohort of channels has resulted in their being implicated in a growing number of processes in an ever-increasing number of cell types. The architectural and regulatory constraints of these acidic Ca2+ stores distinguishes them from other larger Ca2+ sources such as the ER and influx across the plasma membrane. In view of recent advances in the understanding of the modes of operation, we discuss phagocytosis as a template for how endo-lysosomal Ca2+ signals (generated via TPC and TRPML channels) can be integrated in multiple sophisticated ways into biological processes. Phagocytosis illustrates how different endo-lysosomal Ca2+ signals drive different phases of a process, and how these can be altered by disease or infection.
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Affiliation(s)
- Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK.
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK.
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13
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Böck J, Krogsaeter E, Passon M, Chao YK, Sharma S, Grallert H, Peters A, Grimm C. Human genome diversity data reveal that L564P is the predominant TPC2 variant and a prerequisite for the blond hair associated M484L gain-of-function effect. PLoS Genet 2021; 17:e1009236. [PMID: 33465068 PMCID: PMC7845996 DOI: 10.1371/journal.pgen.1009236] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 01/29/2021] [Accepted: 10/29/2020] [Indexed: 12/29/2022] Open
Abstract
The endo-lysosomal two-pore channel (TPC2) has been established as an intracellular cation channel of significant physiological and pathophysiological relevance in recent years. For example, TPC2-/- mice show defects in cholesterol degradation, leading to hypercholesterinemia; TPC2 absence also results in mature-onset obesity, and a role in glucagon secretion and diabetes has been proposed. Infections with bacterial toxins or viruses e.g., cholera toxin or Ebola virus result in reduced infectivity rates in the absence of TPC2 or after pharmacological blockage, and TPC2-/- cancer cells lose their ability to migrate and metastasize efficiently. Finally, melanin production is affected by changes in hTPC2 activity, resulting in pigmentation defects and hair color variation. Here, we analyzed several publicly available genome variation data sets and identified multiple variations in the TPC2 protein in distinct human populations. Surprisingly, one variation, L564P, was found to be the predominant TPC2 isoform on a global scale. By applying endo-lysosomal patch-clamp electrophysiology, we found that L564P is a prerequisite for the previously described M484L gain-of-function effect that is associated with blond hair. Additionally, other gain-of-function variants with distinct geographical and ethnic distribution were discovered and functionally characterized. A meta-analysis of genome-wide association studies was performed, finding the polymorphisms to be associated with both distinct and overlapping traits. In sum, we present the first systematic analysis of variations in TPC2. We functionally characterized the most common variations and assessed their association with various disease traits. With TPC2 emerging as a novel drug target for the treatment of various diseases, this study provides valuable insights into ethnic and geographical distribution of TPC2 polymorphisms and their effects on channel activity.
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Affiliation(s)
- Julia Böck
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Einar Krogsaeter
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Marcel Passon
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Yu-Kai Chao
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sapna Sharma
- Helmholtz Zentrum–Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute of Epidemiology, Neuherberg, Germany
| | - Harald Grallert
- Helmholtz Zentrum–Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute of Epidemiology, Neuherberg, Germany
| | - Annette Peters
- Helmholtz Zentrum–Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute of Epidemiology, Neuherberg, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
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14
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Georgiadou E, Rutter GA. Control by Ca 2+ of mitochondrial structure and function in pancreatic β-cells. Cell Calcium 2020; 91:102282. [PMID: 32961506 PMCID: PMC7116533 DOI: 10.1016/j.ceca.2020.102282] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 12/11/2022]
Abstract
Mitochondria play a central role in glucose metabolism and the stimulation of insulin secretion from pancreatic β-cells. In this review, we discuss firstly the regulation and roles of mitochondrial Ca2+ transport in glucose-regulated insulin secretion, and the molecular machinery involved. Next, we discuss the evidence that mitochondrial dysfunction in β-cells is associated with type 2 diabetes, from a genetic, functional and structural point of view, and then the possibility that these changes may in part be mediated by dysregulation of cytosolic Ca2+. Finally, we review the importance of preserved mitochondrial structure and dynamics for mitochondrial gene expression and their possible relevance to the pathogenesis of type 2 diabetes.
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Affiliation(s)
- Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, du Cane Road, London, W12 0NN, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, du Cane Road, London, W12 0NN, UK.
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15
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Two-pore and TRPML cation channels: Regulators of phagocytosis, autophagy and lysosomal exocytosis. Pharmacol Ther 2020; 220:107713. [PMID: 33141027 DOI: 10.1016/j.pharmthera.2020.107713] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
The old Greek saying "Panta Rhei" ("everything flows") is true for all life and all living things in general. It also becomes nicely evident when looking closely into cells. There, material from the extracellular space is taken up by endocytic processes and transported to endosomes where it is sorted either for recycling or degradation. Cargo is also packaged for export through exocytosis involving the Golgi network, lysosomes and other organelles. Everything in this system is in constant motion and many proteins are necessary to coordinate transport along the different intracellular pathways to avoid chaos. Among these proteins are ion channels., in particular TRPML channels (mucolipins) and two-pore channels (TPCs) which reside on endosomal and lysosomal membranes to speed up movement between organelles, e.g. by regulating fusion and fission; they help readjust pH and osmolarity changes due to such processes, or they promote exocytosis of export material. Pathophysiologically, these channels are involved in neurodegenerative, metabolic, retinal and infectious diseases, cancer, pigmentation defects, and immune cell function, and thus have been proposed as novel pharmacological targets, e.g. for the treatment of lysosomal storage disorders, Duchenne muscular dystrophy, or different types of cancer. Here, we discuss the similarities but also differences of TPCs and TRPMLs in regulating phagocytosis, autophagy and lysosomal exocytosis, and we address the contradictions and open questions in the field relating to the roles TPCs and TRPMLs play in these different processes.
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16
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Bock KW. Modulation of aryl hydrocarbon receptor (AHR) and the NAD +-consuming enzyme CD38: Searches of therapeutic options for nonalcoholic fatty liver disease (NAFLD). Biochem Pharmacol 2020; 175:113905. [PMID: 32169417 DOI: 10.1016/j.bcp.2020.113905] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/06/2020] [Indexed: 11/17/2022]
Abstract
The aryl hydrocarbon receptor (AHR) has been characterized as multifunctional, ligand-activated transcription factor. Recently, evidence has been obtained that AHR is involved in NAD+ and energy homeostasis in cooperation with NAD+-consuming enzymes including CD38, TiPARP and sirtuins. AHR and CD38 may adversely or beneficially modulate nonalcoholic fatty liver disease (NAFLD) which is associated with obesity, a worldwide major health problem. Although nutritional status and lifestyle are the major factors involved in the prevalence of obesity and NAFLD, modulation of AHR and CD38 has been demonstrated to provide therapeutic options. For example, inhibition of hepatic CD38 and activation of AHR, e.g., by dietary flavonoids may beneficially affect NAFLD. In addition, NAFLD-associated decrease of NAD+ may be restored by administration of the NAD+ precursor nicotinamide riboside.
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Affiliation(s)
- Karl Walter Bock
- Institute of Experimental and Clinical Pharmacology and Toxicology, Wilhelmstrasse 56, D-72074 Tübingen, Germany.
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17
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Idevall-Hagren O, Tengholm A. Metabolic regulation of calcium signaling in beta cells. Semin Cell Dev Biol 2020; 103:20-30. [PMID: 32085965 DOI: 10.1016/j.semcdb.2020.01.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/10/2020] [Accepted: 01/28/2020] [Indexed: 12/22/2022]
Abstract
The cytoplasmic Ca2+ concentration ([Ca2+]cyt) regulates a vast number of cellular functions, including insulin secretion from beta cells. The major physiological insulin secretagogue, glucose, triggers [Ca2+]cyt oscillations in beta cells. Synchronization of the oscillations among the beta cells within an islet underlies the generation of pulsatile insulin secretion. This review describes the mechanisms generating [Ca2+]cyt oscillations, the interactions between [Ca2+]cyt and cell metabolism, as well as the contribution of various organelles to the shaping of [Ca2+]cyt signals and insulin secretion. It also discusses how Ca2+ signals are coordinated and spread throughout the islets and data indicating that altered Ca2+ signaling is associated with beta cell dysfunction and development of type 2 diabetes.
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Affiliation(s)
- Olof Idevall-Hagren
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23 Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23 Uppsala, Sweden.
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18
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Webb SE, Kelu JJ, Miller AL. Role of Two-Pore Channels in Embryonic Development and Cellular Differentiation. Cold Spring Harb Perspect Biol 2020; 12:a035170. [PMID: 31358517 PMCID: PMC6942120 DOI: 10.1101/cshperspect.a035170] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Since the identification of nicotinic acid adenine dinucleotide phosphate (NAADP) and its putative target, the two-pore channel (TPC), the NAADP/TPC/Ca2+ signaling pathway has been reported to play a role in a diverse range of functions in a variety of different cell types. TPCs have also been associated with a number of diseases, which arise when their activity is perturbed. In addition, TPCs have been shown to play key roles in various embryological processes and during the differentiation of a variety of cell types. Here, we review the role of NAADP/TPC/Ca2+ signaling during early embryonic development and cellular differentiation. We pay particular attention to the role of TPC2 in the development and maturation of early neuromuscular activity in zebrafish, and during the differentiation of isolated osteoclasts, endothelial cells, and keratinocytes. Our aim is to emphasize the conserved features of TPC-mediated Ca2+ signaling in a number of selected examples.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology (HKUST), Clearwater Bay, Hong Kong, PRC
| | - Jeffrey J Kelu
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology (HKUST), Clearwater Bay, Hong Kong, PRC
| | - Andrew L Miller
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology (HKUST), Clearwater Bay, Hong Kong, PRC
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19
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Lakpa KL, Halcrow PW, Chen X, Geiger JD. Readily Releasable Stores of Calcium in Neuronal Endolysosomes: Physiological and Pathophysiological Relevance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:681-697. [PMID: 31646530 PMCID: PMC7047846 DOI: 10.1007/978-3-030-12457-1_27] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Neurons are long-lived post-mitotic cells that possess an elaborate system of endosomes and lysosomes (endolysosomes) for protein quality control. Relatively recently, endolysosomes were recognized to contain high concentrations (400-600 μM) of readily releasable calcium. The release of calcium from this acidic organelle store contributes to calcium-dependent processes of fundamental physiological importance to neurons including neurotransmitter release, membrane excitability, neurite outgrowth, synaptic remodeling, and cell viability. Pathologically, disturbances of endolysosome structure and/or function have been noted in a variety of neurodegenerative disorders including Alzheimer's disease (AD) and HIV-1 associated neurocognitive disorder (HAND). And, dysregulation of intracellular calcium has been implicated in the neuropathogenesis of these same neurological disorders. Thus, it is important to better understand mechanisms by which calcium is released from endolysosomes as well as the consequences of such release to inter-organellar signaling, physiological functions of neurons, and possible pathological consequences. In doing so, a path forward towards new therapeutic modalities might be facilitated.
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Affiliation(s)
- Koffi L Lakpa
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Peter W Halcrow
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA.
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20
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Chao YK, Chang SY, Grimm C. Endo-Lysosomal Cation Channels and Infectious Diseases. Rev Physiol Biochem Pharmacol 2020; 185:259-276. [PMID: 32748124 DOI: 10.1007/112_2020_31] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Among the infectious diseases caused by pathogenic microorganisms such as bacteria, viruses, parasites, or fungi, the most prevalent ones today are malaria, tuberculosis, influenza, HIV/AIDS, Ebola, dengue fever, and methicillin-resistant Staphylococcus aureus (MRSA) infection, and most recently Covid-19 (SARS-CoV2). Others with a rather devastating history and high fatality rates such as plague, cholera, or typhus seem less threatening today but have not been eradicated, and with a declining efficacy of current antibiotics they ought to be watched carefully. Another emerging issue in this context is health-care associated infection. About 100,000 hospitalized patients in the USA ( www.cdc.gov ) and 33,000 in Europe ( https://www.ecdc.europa.eu ) die each year as a direct consequence of an infection caused by bacteria resistant to antibiotics. Among viral infections, influenza is responsible for about 3-5 million cases of severe illness, and about 250,000 to 500,000 deaths annually ( www.who.int ). About 37 million people are currently living with HIV infection and about one million die from it each year. Coronaviruses such as MERS-CoV, SARS-CoV, but in particular the recent outbreak of Covid-19 (caused by SARS-CoV2) have resulted in large numbers of infections worldwide with an estimated several hundred thousand deaths (anticipated fatality rate: <5%). With a comparatively low mortality rate dengue virus causes between 50 and 100 million infections every year, leading to 50,000 deaths. In contrast, Ebola virus is the causative agent for one of the deadliest viral diseases. The Ebola outbreak in West Africa in 2014 is considered the largest outbreak in history with more than 11,000 deaths. Many of the deadliest pathogens such as Ebola virus, influenza virus, mycobacterium tuberculosis, dengue virus, and cholera exploit the endo-lysosomal trafficking system of host cells for penetration into the cytosol and replication. Defects in endo-lysosomal maturation, trafficking, fusion, or pH homeostasis can efficiently reduce the cytotoxicity caused by these pathogens. Most of these functions critically depend on endo-lysosomal membrane proteins such as transporters and ion channels. In particular, cation channels such as the mucolipins (TRPMLs) or the two-pore channels (TPCs) are involved in all of these aspects of endo-lysosomal integrity. In this review we will discuss the correlations between pathogen toxicity and endo-lysosomal cation channel function, and their potential as drug targets for infectious disease therapy.
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Affiliation(s)
- Yu-Kai Chao
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sui-Yuan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Laboratory Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität, Munich, Germany.
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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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22
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Galione A, Chuang KT. Pyridine Nucleotide Metabolites and Calcium Release from Intracellular Stores. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1131:371-394. [PMID: 31646518 DOI: 10.1007/978-3-030-12457-1_15] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ca2+ signals are probably the most common intracellular signaling cellular events, controlling an extensive range of responses in virtually all cells. Many cellular stimuli, often acting at cell surface receptors, evoke Ca2+ signals by mobilizing Ca2+ from intracellular stores. Inositol trisphosphate (IP3) was the first messenger shown to link events at the plasma membrane to release Ca2+ from the endoplasmic reticulum (ER), through the activation of IP3-gated Ca2+ release channels (IP3 receptors). Subsequently, two additional Ca2+ mobilizing messengers were discovered, cADPR and NAADP. Both are metabolites of pyridine nucleotides, and may be produced by the same class of enzymes, ADP-ribosyl cyclases, such as CD38. Whilst cADPR mobilizes Ca2+ from the ER by activation of ryanodine receptors (RyRs), NAADP releases Ca2+ from acidic stores by a mechanism involving the activation of two pore channels (TPCs). In addition, other pyridine nucleotides have emerged as intracellular messengers. ADP-ribose and 2'-deoxy-ADPR both activate TRPM2 channels which are expressed at the plasma membrane and in lysosomes.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK.
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford, UK
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23
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Ježek P, Jabůrek M, Plecitá-Hlavatá L. Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes. Antioxid Redox Signal 2019; 31:722-751. [PMID: 30450940 PMCID: PMC6708273 DOI: 10.1089/ars.2018.7656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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24
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Functions of aryl hydrocarbon receptor (AHR) and CD38 in NAD metabolism and nonalcoholic steatohepatitis (NASH). Biochem Pharmacol 2019; 169:113620. [PMID: 31465774 DOI: 10.1016/j.bcp.2019.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/22/2019] [Indexed: 12/20/2022]
Abstract
Aryl hydrocarbon receptor (AHR), identified in studies of dioxin toxicity, has been characterized as ligand-activated transcription factor involved in diverse functions including microbial defense, cell proliferation, immunity and NAD metabolism. AHR targets of the latter function are PARPs/ARTs and CD38 that are regulating glucose and lipid metabolism via NAD-dependent sirtuins. Deregulation of these pathways may facilitate obesity and age-dependent pathologies. The present commentary is focused on AHR and CD38 signaling in liver. CD38 is functioning as ectoNADase and Ca2+ mobilizing enzyme in endoplasmic reticulum and endolysosomal membranes. Deregulation of TCDD-activated AHR and CD38 may facilitate hepatic steatosis and inflammation. However, these proteins are also involved in protection against inflammation and CD38-mediated age-related decreased NAD levels that may be responsible for neurodegeneration. Further knowledge about the complexity of these pathways is needed to avoid pathologies. Therapeutic modulation of AHR and CD38 remains a challenging task.
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25
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Asfaha TY, Gunaratne GS, Johns ME, Marchant JS, Walseth TF, Slama JT. The synthesis and characterization of a clickable-photoactive NAADP analog active in human cells. Cell Calcium 2019; 83:102060. [PMID: 31442840 DOI: 10.1016/j.ceca.2019.102060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/11/2019] [Accepted: 07/15/2019] [Indexed: 12/11/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca2+ mobilizing second messenger which triggers Ca2+ release in both sea urchin egg homogenates and in mammalian cells. The NAADP binding protein has not been identified and the regulation of NAADP mediated Ca2+ release remains controversial. To address this issue, we have synthesized an NAADP analog in which 3-azido-5-azidomethylbenzoic acid is attached to the amino group of 5-(3-aminopropyl)-NAADP to produce an NAADP analog which is both a photoaffinity label and clickable. This 'all-in-one-clickable' NAADP (AIOC-NAADP) elicited Ca2+ release when microinjected into cultured human SKBR3 cells at low concentrations. In contrast, it displayed little activity in sea urchin egg homogenates where very high concentrations were required to elicit Ca2+ release. In mammalian cell homogenates, incubation with low concentrations of [32P]AIOC-NAADP followed by irradiation with UV light resulted in labeling 23 kDa protein(s). Competition between [32P]AIOC-NAADP and increasing concentrations of NAADP demonstrated that the labeling was selective. We show that this label recognizes and selectively photodervatizes the 23 kDa NAADP binding protein(s) in cultured human cells identified in previous studies using [32P]5-N3-NAADP.
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Affiliation(s)
- Timnit Yosef Asfaha
- Department of Medicinal and Biological Chemistry, University of Toledo College of Pharmacy and Pharmaceutical Sciences, 3000 Arlington Avenue, Toledo, OH, 43614, United States
| | - Gihan S Gunaratne
- Department of Pharmacology, University of Minnesota Medical School, 312 Church St., Minneapolis, MN, 55455-0217, United States
| | - Malcolm E Johns
- Department of Pharmacology, University of Minnesota Medical School, 312 Church St., Minneapolis, MN, 55455-0217, United States
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226-0509, United States
| | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota Medical School, 312 Church St., Minneapolis, MN, 55455-0217, United States.
| | - James T Slama
- Department of Medicinal and Biological Chemistry, University of Toledo College of Pharmacy and Pharmaceutical Sciences, 3000 Arlington Avenue, Toledo, OH, 43614, United States.
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26
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Faris P, Pellavio G, Ferulli F, Di Nezza F, Shekha M, Lim D, Maestri M, Guerra G, Ambrosone L, Pedrazzoli P, Laforenza U, Montagna D, Moccia F. Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) Induces Intracellular Ca 2+ Release through the Two-Pore Channel TPC1 in Metastatic Colorectal Cancer Cells. Cancers (Basel) 2019; 11:cancers11040542. [PMID: 30991693 PMCID: PMC6521149 DOI: 10.3390/cancers11040542] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/09/2019] [Indexed: 12/12/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) gates two-pore channels 1 and 2 (TPC1 and TPC2) to elicit endo-lysosomal (EL) Ca2+ release. NAADP-induced EL Ca2+ signals may be amplified by the endoplasmic reticulum (ER) through the Ca2+-induced Ca2+ release mechanism (CICR). Herein, we aimed at assessing for the first time the role of EL Ca2+ signaling in primary cultures of human metastatic colorectal carcinoma (mCRC) by exploiting Ca2+ imaging and molecular biology techniques. The lysosomotropic agent, Gly-Phe β-naphthylamide (GPN), and nigericin, which dissipates the ΔpH which drives Ca2+ refilling of acidic organelles, caused massive Ca2+ release in the presence of a functional inositol-1,4,5-trisphosphate (InsP3)-sensitive ER Ca2+ store. Liposomal delivery of NAADP induced a transient Ca2+ release that was reduced by GPN and NED-19, a selective TPC antagonist. Pharmacological and genetic manipulations revealed that the Ca2+ response to NAADP was triggered by TPC1, the most expressed TPC isoform in mCRC cells, and required ER-embedded InsP3 receptors. Finally, NED-19 and genetic silencing of TPC1 reduced fetal calf serum-induced Ca2+ signals, proliferation, and extracellular signal-regulated kinase and Akt phoshorylation in mCRC cells. These data demonstrate that NAADP-gated TPC1 could be regarded as a novel target for alternative therapies to treat mCRC.
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Affiliation(s)
- Pawan Faris
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100 Pavia, Italy.
- Research Centre, Salahaddin University-Erbil, 44001 Erbil, Kurdistan-Region of Iraq, Iraq.
| | - Giorgia Pellavio
- Human Physiology Unit, via Forlanini 6, Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.
| | - Federica Ferulli
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
| | - Francesca Di Nezza
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, 86100 Campobasso, Italy.
| | - Mudhir Shekha
- Research Centre, Salahaddin University-Erbil, 44001 Erbil, Kurdistan-Region of Iraq, Iraq.
- Department of Pathological Analysis, College of Science, Knowledge University, 074016 Erbil, Kurdistan-Region of Iraq, Iraq.
| | - Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, 28100 Novara, Italy.
| | - Marcello Maestri
- Unit of General Surgery, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
- Department of Sciences Clinic-Surgical, Diagnostic and Pediatric, University of Pavia, 27100 Pavia, Italy.
| | - Germano Guerra
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, 86100 Campobasso, Italy.
| | - Luigi Ambrosone
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, 86100 Campobasso, Italy.
| | - Paolo Pedrazzoli
- Medical Oncology, oundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
| | - Umberto Laforenza
- Human Physiology Unit, via Forlanini 6, Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.
| | - Daniela Montagna
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
- Department of Sciences Clinic-Surgical, Diagnostic and Pediatric, University of Pavia, 27100 Pavia, Italy.
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100 Pavia, Italy.
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27
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Sabatini PV, Speckmann T, Lynn FC. Friend and foe: β-cell Ca 2+ signaling and the development of diabetes. Mol Metab 2019; 21:1-12. [PMID: 30630689 PMCID: PMC6407368 DOI: 10.1016/j.molmet.2018.12.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/03/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The divalent cation Calcium (Ca2+) regulates a wide range of processes in disparate cell types. Within insulin-producing β-cells, increases in cytosolic Ca2+ directly stimulate insulin vesicle exocytosis, but also initiate multiple signaling pathways. Mediated through activation of downstream kinases and transcription factors, Ca2+-regulated signaling pathways leverage substantial influence on a number of critical cellular processes within the β-cell. Additionally, there is evidence that prolonged activation of these same pathways is detrimental to β-cell health and may contribute to Type 2 Diabetes pathogenesis. SCOPE OF REVIEW This review aims to briefly highlight canonical Ca2+ signaling pathways in β-cells and how β-cells regulate the movement of Ca2+ across numerous organelles and microdomains. As a main focus, this review synthesizes experimental data from in vitro and in vivo models on both the beneficial and detrimental effects of Ca2+ signaling pathways for β-cell function and health. MAJOR CONCLUSIONS Acute increases in intracellular Ca2+ stimulate a number of signaling cascades, resulting in (de-)phosphorylation events and activation of downstream transcription factors. The short-term stimulation of these Ca2+ signaling pathways promotes numerous cellular processes critical to β-cell function, including increased viability, replication, and insulin production and secretion. Conversely, chronic stimulation of Ca2+ signaling pathways increases β-cell ER stress and results in the loss of β-cell differentiation status. Together, decades of study demonstrate that Ca2+ movement is tightly regulated within the β-cell, which is at least partially due to its dual roles as a potent signaling molecule.
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Affiliation(s)
- Paul V Sabatini
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada; Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada; Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Thilo Speckmann
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada; Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Francis C Lynn
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada; Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
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28
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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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He H, Holl K, DeBehnke S, Yeo CT, Hansen P, Gebre AK, Leone-Kabler S, Ruas M, Parks JS, Parrington J, Solberg Woods LC. Tpcn2 knockout mice have improved insulin sensitivity and are protected against high-fat diet-induced weight gain. Physiol Genomics 2018; 50:605-614. [PMID: 29750602 DOI: 10.1152/physiolgenomics.00135.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Type 2 diabetes is a complex disorder affected by multiple genes and the environment. Our laboratory has shown that in response to a glucose challenge, two-pore channel 2 ( Tpcn2) knockout mice exhibit a decreased insulin response but normal glucose clearance, suggesting they have improved insulin sensitivity compared with wild-type mice. We tested the hypothesis that improved insulin sensitivity in Tpcn2 knockout mice would protect against the negative effects of a high fat diet. Male and female Tpcn2 knockout (KO), heterozygous (Het), and wild-type (WT) mice were fed a low-fat (LF) or high-fat (HF) diet for 24 wk. HF diet significantly increases body weight in WT mice relative to those on the LF diet; this HF diet-induced increase in body weight is blunted in the Het and KO mice. Despite the protection against diet-induced weight gain, however, Tpcn2 KO mice are not protected against HF-diet-induced changes in glucose or insulin area under the curve during glucose tolerance tests in female mice, while HF diet has no significant effect on glucose tolerance in the male mice, regardless of genotype. Glucose disappearance during an insulin tolerance test is augmented in male KO mice, consistent with our previous findings suggesting enhanced insulin sensitivity in these mice. Male KO mice exhibit increased fasting plasma total cholesterol and triglyceride concentrations relative to WT mice on the LF diet, but this difference disappears in HF diet-fed mice where there is increased cholesterol and triglycerides across all genotypes. These data demonstrate that knockout of Tpcn2 may increase insulin action in male, but not female, mice. In addition, both male and female KO mice are protected against diet-induced weight gain, but this protection is likely independent from glucose tolerance, insulin sensitivity, and plasma lipid levels.
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Affiliation(s)
- Hong He
- Department of Pediatrics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Katie Holl
- Department of Pediatrics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Sarah DeBehnke
- Department of Pediatrics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Chay Teng Yeo
- Department of Pediatrics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Polly Hansen
- Department of Pediatrics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Abraham K Gebre
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine , Winston Salem, North Carolina
| | - Sandra Leone-Kabler
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine , Winston Salem, North Carolina
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford , Oxford , United Kingdom
| | - John S Parks
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine , Winston Salem, North Carolina
| | - John Parrington
- Department of Pharmacology, University of Oxford , Oxford , United Kingdom
| | - Leah C Solberg Woods
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest School of Medicine , Winston Salem, North Carolina
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Hamilton A, Zhang Q, Salehi A, Willems M, Knudsen JG, Ringgaard AK, Chapman CE, Gonzalez-Alvarez A, Surdo NC, Zaccolo M, Basco D, Johnson PRV, Ramracheya R, Rutter GA, Galione A, Rorsman P, Tarasov AI. Adrenaline Stimulates Glucagon Secretion by Tpc2-Dependent Ca 2+ Mobilization From Acidic Stores in Pancreatic α-Cells. Diabetes 2018; 67:1128-1139. [PMID: 29563152 PMCID: PMC6258900 DOI: 10.2337/db17-1102] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 03/14/2018] [Indexed: 12/25/2022]
Abstract
Adrenaline is a powerful stimulus of glucagon secretion. It acts by activation of β-adrenergic receptors, but the downstream mechanisms have only been partially elucidated. Here, we have examined the effects of adrenaline in mouse and human α-cells by a combination of electrophysiology, imaging of Ca2+ and PKA activity, and hormone release measurements. We found that stimulation of glucagon secretion correlated with a PKA- and EPAC2-dependent (inhibited by PKI and ESI-05, respectively) elevation of [Ca2+]i in α-cells, which occurred without stimulation of electrical activity and persisted in the absence of extracellular Ca2+ but was sensitive to ryanodine, bafilomycin, and thapsigargin. Adrenaline also increased [Ca2+]i in α-cells in human islets. Genetic or pharmacological inhibition of the Tpc2 channel (that mediates Ca2+ release from acidic intracellular stores) abolished the stimulatory effect of adrenaline on glucagon secretion and reduced the elevation of [Ca2+]i Furthermore, in Tpc2-deficient islets, ryanodine exerted no additive inhibitory effect. These data suggest that β-adrenergic stimulation of glucagon secretion is controlled by a hierarchy of [Ca2+]i signaling in the α-cell that is initiated by cAMP-induced Tpc2-dependent Ca2+ release from the acidic stores and further amplified by Ca2+-induced Ca2+ release from the sarco/endoplasmic reticulum.
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Affiliation(s)
- Alexander Hamilton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Albert Salehi
- Institute of Neuroscience of Physiology, Department of Physiology, Metabolic Research Unit, University of Göteborg, Göteborg, Sweden
| | - Mara Willems
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Jakob G Knudsen
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Anna K Ringgaard
- Diabetes Research, Department of Stem Cell Biology, Novo Nordisk A/S, Måløv, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline E Chapman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Alejandro Gonzalez-Alvarez
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Nicoletta C Surdo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K
| | - Davide Basco
- Center for Integrative Genomics, Université de Lausanne, Lausanne, Switzerland
| | - Paul R V Johnson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
- Oxford National Institute for Health Research, Biomedical Research Centre, Oxford, U.K
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, U.K
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, U.K
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K.
- Institute of Neuroscience of Physiology, Department of Physiology, Metabolic Research Unit, University of Göteborg, Göteborg, Sweden
- Oxford National Institute for Health Research, Biomedical Research Centre, Oxford, U.K
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Headington, U.K.
- Oxford National Institute for Health Research, Biomedical Research Centre, Oxford, U.K
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Two-pore channels and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1678-1686. [PMID: 29746898 PMCID: PMC6162333 DOI: 10.1016/j.bbamcr.2018.05.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 05/03/2018] [Indexed: 01/25/2023]
Abstract
Two-pore channels (TPCs) are Ca2+-permeable endo-lysosomal ion channels subject to multi-modal regulation. They mediate their physiological effects through releasing Ca2+ from acidic organelles in response to cues such as the second messenger, NAADP. Here, we review emerging evidence linking TPCs to disease. We discuss how perturbing both local and global Ca2+ changes mediated by TPCs through chemical and/or molecular manipulations can induce or reverse disease phenotypes. We cover evidence from models of Parkinson's disease, non-alcoholic fatty liver disease, Ebola infection, cancer, cardiac dysfunction and diabetes. A need for more drugs targeting TPCs is identified.
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Rorsman P, Ashcroft FM. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev 2018; 98:117-214. [PMID: 29212789 PMCID: PMC5866358 DOI: 10.1152/physrev.00008.2017] [Citation(s) in RCA: 446] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/30/2017] [Accepted: 06/18/2017] [Indexed: 12/14/2022] Open
Abstract
The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity, and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM.
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Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frances M Ashcroft
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Rutter GA, Hodson DJ, Chabosseau P, Haythorne E, Pullen TJ, Leclerc I. Local and regional control of calcium dynamics in the pancreatic islet. Diabetes Obes Metab 2017; 19 Suppl 1:30-41. [PMID: 28466490 DOI: 10.1111/dom.12990] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/19/2017] [Accepted: 04/24/2017] [Indexed: 12/31/2022]
Abstract
Ca2+ is the key intracellular regulator of insulin secretion, acting in the β-cell as the ultimate trigger for exocytosis. In response to high glucose, ATP-sensitive K+ channel closure and plasma membrane depolarization engage a sophisticated machinery to drive pulsatile cytosolic Ca2+ changes. Voltage-gated Ca2+ channels, Ca2+ -activated K+ channels and Na+ /Ca2+ exchange all play important roles. The use of targeted Ca2+ probes has revealed that during each cytosolic Ca2+ pulse, uptake of Ca2+ by mitochondria, endoplasmic reticulum (ER), secretory granules and lysosomes fine-tune cytosolic Ca2+ dynamics and control organellar function. For example, changes in the expression of the Ca2+ -binding protein Sorcin appear to provide a link between ER Ca2+ levels and ER stress, affecting β-cell function and survival. Across the islet, intercellular communication between highly interconnected "hubs," which act as pacemaker β-cells, and subservient "followers," ensures efficient insulin secretion. Loss of connectivity is seen after the deletion of genes associated with type 2 diabetes (T2D) and follows metabolic and inflammatory insults that characterize this disease. Hubs, which typically comprise ~1%-10% of total β-cells, are repurposed for their specialized role by expression of high glucokinase (Gck) but lower Pdx1 and Nkx6.1 levels. Single cell-omics are poised to provide a deeper understanding of the nature of these cells and of the networks through which they communicate. New insights into the control of both the intra- and intercellular Ca2+ dynamics may thus shed light on T2D pathology and provide novel opportunities for therapy.
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Affiliation(s)
- Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, COMPARE University of Birmingham and University of Nottingham Midlands, Birmingham, UK
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
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Grimm C, Chen CC, Wahl-Schott C, Biel M. Two-Pore Channels: Catalyzers of Endolysosomal Transport and Function. Front Pharmacol 2017; 8:45. [PMID: 28223936 PMCID: PMC5293812 DOI: 10.3389/fphar.2017.00045] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/20/2017] [Indexed: 01/17/2023] Open
Abstract
Two-pore channels (TPCs) have recently emerged as a novel class of non-selective cation channels in the endolysosomal system. There are two members in the human genome, TPC1 and TPC2. Studies with TPC knockout and knockdown models have revealed that these channels participate in the regulation of multiple endolysosomal trafficking pathways which when dysregulated can lead to or influence the development of a range of different diseases such as lysosomal storage, metabolic, or infectious diseases. TPCs have been demonstrated to be activated by different endogenous stimuli, PI(3,5)P2 and NAADP, and ATP has been found to block TPC activation via mTOR. Loss of TPCs can lead to obesity and hypercholesterolemia, and to a slow-down of intracellular virus and bacterial toxin trafficking, it can affect VEGF-induced neoangiogenesis, autophagy, human hair pigmentation or the acrosome reaction in sperm. Moreover, physiological roles of TPCs in cardiac myocytes and pancreatic β cells have been postulated.
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Affiliation(s)
- Christian Grimm
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Cheng-Chang Chen
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Christian Wahl-Schott
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich, Ludwig Maximilian University of MunichMunich, Germany
- Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of MunichMunich, Germany
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Abstract
Organellar two-pore channels (TPCs) contain two copies of a Shaker-like six-transmembrane (6-TM) domain in each subunit and are ubiquitously expressed in plants and animals. Interestingly, plant and animal TPCs share high sequence similarity in the filter region, yet exhibit drastically different ion selectivity. Plant TPC1 functions as a nonselective cation channel on the vacuole membrane, whereas mammalian TPC channels have been shown to be endo/lysosomal Na+-selective or Ca2+-release channels. In this study, we performed systematic characterization of the ion selectivity of TPC1 from Arabidopsis thaliana (AtTPC1) and compared its selectivity with the selectivity of human TPC2 (HsTPC2). We demonstrate that AtTPC1 is selective for Ca2+ over Na+, but nonselective among monovalent cations (Li+, Na+, and K+). Our results also confirm that HsTPC2 is a Na+-selective channel activated by phosphatidylinositol 3,5-bisphosphate. Guided by our recent structure of AtTPC1, we converted AtTPC1 to a Na+-selective channel by mimicking the selectivity filter of HsTPC2 and identified key residues in the TPC filters that differentiate the selectivity between AtTPC1 and HsTPC2. Furthermore, the structure of the Na+-selective AtTPC1 mutant elucidates the structural basis for Na+ selectivity in mammalian TPCs.
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36
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García-Rúa V, Feijóo-Bandín S, García-Vence M, Aragón-Herrera A, Bravo SB, Rodríguez-Penas D, Mosquera-Leal A, Lear PV, Parrington J, Alonso J, Roselló-Lletí E, Portolés M, Rivera M, González-Juanatey JR, Lago F. Metabolic alterations derived from absence of Two-Pore Channel 1 at cardiac level. J Biosci 2016; 41:643-658. [DOI: 10.1007/s12038-016-9647-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Feijóo-Bandín S, García-Vence M, García-Rúa V, Roselló-Lletí E, Portolés M, Rivera M, González-Juanatey JR, Lago F. Two-pore channels (TPCs): Novel voltage-gated ion channels with pleiotropic functions. Channels (Austin) 2016; 11:20-33. [PMID: 27440385 DOI: 10.1080/19336950.2016.1213929] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Two-pore channels (TPC1-3) comprise a subfamily of the eukaryotic voltage-gated ion channels (VGICs) superfamily that are mainly expressed in acidic stores in plants and animals. TPCS are widespread across the animal kingdom, with primates, mice and rats lacking TPC3, and mainly act as Ca+ and Na+ channels, although it was also suggested that they could be permeable to other ions. Nowadays, TPCs have been related to the development of different diseases, including Parkinson´s disease, obesity or myocardial ischemia. Due to this, their study has raised the interest of the scientific community to try to understand their mechanism of action in order to be able to develop an efficient drug that could regulate TPCs activity. In this review, we will provide an updated view regarding TPCs structure, function and activation, as well as their role in different pathophysiological processes.
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Affiliation(s)
- Sandra Feijóo-Bandín
- a Cellular and Molecular Cardiology Research Unit and Department of Cardiology , Institute of Biomedical Research and University Clinical Hospital , Santiago de Compostela , Spain
| | - María García-Vence
- a Cellular and Molecular Cardiology Research Unit and Department of Cardiology , Institute of Biomedical Research and University Clinical Hospital , Santiago de Compostela , Spain
| | - Vanessa García-Rúa
- a Cellular and Molecular Cardiology Research Unit and Department of Cardiology , Institute of Biomedical Research and University Clinical Hospital , Santiago de Compostela , Spain
| | - Esther Roselló-Lletí
- b Cardiocirculatory Unit, Health Institute of La Fe University Hospital , Valencia , Spain
| | - Manuel Portolés
- b Cardiocirculatory Unit, Health Institute of La Fe University Hospital , Valencia , Spain
| | - Miguel Rivera
- b Cardiocirculatory Unit, Health Institute of La Fe University Hospital , Valencia , Spain
| | - José Ramón González-Juanatey
- a Cellular and Molecular Cardiology Research Unit and Department of Cardiology , Institute of Biomedical Research and University Clinical Hospital , Santiago de Compostela , Spain
| | - Francisca Lago
- a Cellular and Molecular Cardiology Research Unit and Department of Cardiology , Institute of Biomedical Research and University Clinical Hospital , Santiago de Compostela , Spain
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Regulation of lysosomal ion homeostasis by channels and transporters. SCIENCE CHINA-LIFE SCIENCES 2016; 59:777-91. [PMID: 27430889 PMCID: PMC5147046 DOI: 10.1007/s11427-016-5090-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/02/2016] [Indexed: 02/05/2023]
Abstract
Lysosomes are the major organelles that carry out degradation functions. They integrate and digest materials compartmentalized by endocytosis, phagocytosis or autophagy. In addition to more than 60 hydrolases residing in the lysosomes, there are also ion channels and transporters that mediate the flux or transport of H+, Ca2+, Na+, K+, and Cl− across the lysosomal membranes. Defects in ionic exchange can lead to abnormal lysosome morphology, defective vesicle trafficking, impaired autophagy, and diseases such as neurodegeneration and lysosomal storage disorders. The latter are characterized by incomplete lysosomal digestion and accumulation of toxic materials inside enlarged intracellular vacuoles. In addition to degradation, recent studies have revealed the roles of lysosomes in metabolic pathways through kinases such as mechanistic target of rapamycin (mTOR) and transcriptional regulation through calcium signaling molecules such as transcription factor EB (TFEB) and calcineurin. Owing to the development of new approaches including genetically encoded fluorescence probes and whole endolysosomal patch clamp recording techniques, studies on lysosomal ion channels have made remarkable progress in recent years. In this review, we will focus on the current knowledge of lysosome-resident ion channels and transporters, discuss their roles in maintaining lysosomal function, and evaluate how their dysfunction can result in disease.
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Fan Y, Li X, Zhang Y, Fan X, Zhang N, Zheng H, Song Y, Shen C, Shen J, Ren F, Yang J. Genetic Variants of TPCN2 Associated with Type 2 Diabetes Risk in the Chinese Population. PLoS One 2016; 11:e0149614. [PMID: 26918892 PMCID: PMC4769022 DOI: 10.1371/journal.pone.0149614] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 02/02/2016] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE The aim of this study was to determine whether TPCN2 genetic variants are associated with type 2 diabetes and to elucidate which variants in TPCN2 confer diabetes susceptibility in the Chinese population. RESEARCH DESIGN AND METHODS The sample population included 384 patients with type 2 diabetes and 1468 controls. Anthropometric parameters, glycemic and lipid profiles and insulin resistance were measured. We selected 6 TPCN2 tag single nucleotide polymorphisms (rs35264875, rs267603153, rs267603154, rs3829241, rs1551305, and rs3750965). Genotypes were determined using a Sequenom MassARRAY SNP genotyping system. RESULTS Ultimately, we genotyped 3 single nucleotide polymorphisms (rs3750965, rs3829241, and rs1551305) in all individuals. There was a 5.1% higher prevalence of the rs1551305 variant allele in type 2 diabetes individuals (A) compared with wild-type homozygous individuals (G). The AA genotype of rs1551305 was associated with a higher diabetes risk (p<0.05). The distributions of rs3829241 and rs3750965 polymorphisms were not significantly different between the two groups. HOMA-%B of subjects harboring the AA genotype of rs1551305 decreased by 14.87% relative to the GG genotype. CONCLUSIONS TPCN2 plays a role in metabolic regulation, and the rs1551305 single nucleotide polymorphism is associated with type 2 diabetes risk. Future work will begin to unravel the underlying mechanisms.
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Affiliation(s)
- Yujuan Fan
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Xuesong Li
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Yu Zhang
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Xiaofang Fan
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Ning Zhang
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Hui Zheng
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Yuping Song
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Chunfang Shen
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Jiayi Shen
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Fengdong Ren
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
| | - Jialin Yang
- Department of Endocrinology, Central Hospital of Minhang District, Minhang Hospital affiliated with Fudan University, Shanghai, People’s Republic of China
- * E-mail:
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Favia A, Pafumi I, Desideri M, Padula F, Montesano C, Passeri D, Nicoletti C, Orlandi A, Del Bufalo D, Sergi M, Ziparo E, Palombi F, Filippini A. NAADP-Dependent Ca(2+) Signaling Controls Melanoma Progression, Metastatic Dissemination and Neoangiogenesis. Sci Rep 2016; 6:18925. [PMID: 26733361 PMCID: PMC4702115 DOI: 10.1038/srep18925] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/30/2015] [Indexed: 02/06/2023] Open
Abstract
A novel transduction pathway for the powerful angiogenic factor VEGF has been recently shown in endothelial cells to operate through NAADP-controlled intracellular release of Ca2+. In the present report the possible involvement of NAADP-controlled Ca2+ signaling in tumor vascularization, growth and metastatic dissemination was investigated in a murine model of VEGF-secreting melanoma. Mice implanted with B16 melanoma cells were treated with NAADP inhibitor Ned-19 every second day for 4 weeks and tumor growth, vascularization and metastatization were evaluated. Control specimens developed well vascularized tumors and lung metastases, whereas in Ned-19-treated mice tumor growth and vascularization as well as lung metastases were strongly inhibited. In vitro experiments showed that Ned-19 treatment controls the growth of B16 cells in vitro, their migratory ability, adhesive properties and VEGFR2 expression, indicating NAADP involvement in intercellular autocrine signaling. To this regard, Ca2+ imaging experiments showed that the response of B16 cells to VEGF stimulation is NAADP-dependent. The whole of these observations indicate that NAADP-controlled Ca2+ signaling can be relevant not only for neoangiogenesis but also for direct control of tumor cells.
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Affiliation(s)
- Annarita Favia
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Irene Pafumi
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Marianna Desideri
- Experimental Chemotherapy Laboratory, Regina Elena National Cancer Institute, 53 Via E. Chianesi, 00144, Rome, Italy
| | - Fabrizio Padula
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Camilla Montesano
- Department of Chemistry, SAPIENZA University of Rome, 5 Piazzale Aldo Moro, 00185 Rome, Italy
| | - Daniela Passeri
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Via di Tor Vegata, 00173 Rome, Italy
| | - Carmine Nicoletti
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Augusto Orlandi
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Via di Tor Vegata, 00173 Rome, Italy
| | - Donatella Del Bufalo
- Experimental Chemotherapy Laboratory, Regina Elena National Cancer Institute, 53 Via E. Chianesi, 00144, Rome, Italy
| | - Manuel Sergi
- Faculty of Biosciences and Technologies for Food, Agriculture and Environment, University of Teramo, 1 Via R. Balzarini, 64023 Teramo, Italy
| | - Elio Ziparo
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Fioretta Palombi
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
| | - Antonio Filippini
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology,SAPIENZA University of Rome, 16 Via A. Scarpa, 00161 Rome, Italy
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41
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Cane MC, Parrington J, Rorsman P, Galione A, Rutter GA. The two pore channel TPC2 is dispensable in pancreatic β-cells for normal Ca²⁺ dynamics and insulin secretion. Cell Calcium 2015; 59:32-40. [PMID: 26769314 PMCID: PMC4751975 DOI: 10.1016/j.ceca.2015.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/08/2015] [Accepted: 12/21/2015] [Indexed: 12/21/2022]
Abstract
Ca(2+) signals are central to the stimulation of insulin secretion from pancreatic β-cells by glucose and other agents, including glucagon-like peptide-1 (GLP-1). Whilst Ca(2+) influx through voltage-gated Ca(2+) channels on the plasma membrane is a key trigger for glucose-stimulated secretion, mobilisation of Ca(2+) from acidic stores has been implicated in the control of more localised Ca(2+) changes and membrane potential. Nicotinic acid adenine dinucleotide phosphate (NAADP), generated in β-cells in response to high glucose, is a potent mobiliser of these stores, and has been proposed to act through two pore channels (TPC1 and TPC2, murine gene names Tpcn1 and Tpcn2). Whilst the role of TPC1 in the control of Ca(2+) mobilisation and insulin secretion was recently confirmed, conflicting data exist for TPC2. Here, we used the selective and efficient deleter strain, Ins1Cre to achieve β-cell selective deletion of the Tpcn2 gene in mice. βTpcn2 KO mice displayed normal intraperitoneal and oral glucose tolerance, and glucose-stimulated Ca(2+) dynamics and insulin secretion from islets were similarly normal. GLP-1-induced Ca(2+) increases involved an increase in oscillation frequency from 4.35 to 4.84 per minute (p=0.04) at 8mM glucose, and this increase was unaffected by the absence of Tpcn2. The current data thus indicate that TPC2 is not absolutely required for normal glucose- or incretin-stimulated insulin secretion from the β-cell. Our findings suggest that TPC1, whose expression tended to increase in Tpcn2 null islets, might be sufficient to support normal Ca(2+) dynamics in response to stimulation by nutrients or incretins.
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Affiliation(s)
- Matthew C Cane
- Section of Cell Biology and Functional Genomics, Imperial College London, Du Cane Road, W12 0NN London, UK
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, OX1 3QT, UK
| | - Patrik Rorsman
- The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, OX1 3QT, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Imperial College London, Du Cane Road, W12 0NN London, UK.
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42
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Hui L, Geiger NH, Bloor-Young D, Churchill GC, Geiger JD, Chen X. Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons. Cell Calcium 2015; 58:617-27. [PMID: 26475051 DOI: 10.1016/j.ceca.2015.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/02/2015] [Accepted: 10/04/2015] [Indexed: 01/22/2023]
Abstract
Neurons possess an elaborate system of endolysosomes. Recently, endolysosomes were found to have readily releasable stores of intracellular calcium; however, relatively little is known about how such 'acidic calcium stores' affect calcium signaling in neurons. Here we demonstrated in primary cultured neurons that calcium released from acidic calcium stores triggered calcium influx across the plasma membrane, a phenomenon we have termed "acidic store-operated calcium entry (aSOCE)". aSOCE was functionally distinct from store-operated calcium release and calcium entry involving endoplasmic reticulum. aSOCE appeared to be governed by N-type calcium channels (NTCCs) because aSOCE was attenuated significantly by selectively blocking NTCCs or by siRNA knockdown of NTCCs. Furthermore, we demonstrated that NTCCs co-immunoprecipitated with the lysosome associated membrane protein 1 (LAMP1), and that aSOCE is accompanied by increased cell-surface expression levels of NTCC and LAMP1 proteins. Moreover, we demonstrated that siRNA knockdown of LAMP1 or Rab27a, both of which are key proteins involved in lysosome exocytosis, attenuated significantly aSOCE. Taken together our data suggest that aSOCE occurs in neurons, that aSOCE plays an important role in regulating the levels and actions of intraneuronal calcium, and that aSOCE is regulated at least in part by exocytotic insertion of N-type calcium channels into plasma membranes through LAMP1-dependent lysosome exocytosis.
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Affiliation(s)
- Liang Hui
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Nicholas H Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Duncan Bloor-Young
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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43
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Capel RA, Bolton EL, Lin WK, Aston D, Wang Y, Liu W, Wang X, Burton RAB, Bloor-Young D, Shade KT, Ruas M, Parrington J, Churchill GC, Lei M, Galione A, Terrar DA. Two-pore Channels (TPC2s) and Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) at Lysosomal-Sarcoplasmic Reticular Junctions Contribute to Acute and Chronic β-Adrenoceptor Signaling in the Heart. J Biol Chem 2015; 290:30087-98. [PMID: 26438825 PMCID: PMC4705968 DOI: 10.1074/jbc.m115.684076] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 12/12/2022] Open
Abstract
Ca2+-permeable type 2 two-pore channels (TPC2) are lysosomal proteins required for nicotinic acid adenine dinucleotide phosphate (NAADP)-evoked Ca2+ release in many diverse cell types. Here, we investigate the importance of TPC2 proteins for the physiology and pathophysiology of the heart. NAADP-AM failed to enhance Ca2+ responses in cardiac myocytes from Tpcn2−/− mice, unlike myocytes from wild-type (WT) mice. Ca2+/calmodulin-dependent protein kinase II inhibitors suppressed actions of NAADP in myocytes. Ca2+ transients and contractions accompanying action potentials were increased by isoproterenol in myocytes from WT mice, but these effects of β-adrenoreceptor stimulation were reduced in myocytes from Tpcn2−/− mice. Increases in amplitude of L-type Ca2+ currents evoked by isoproterenol remained unchanged in myocytes from Tpcn2−/− mice showing no loss of β-adrenoceptors or coupling mechanisms. Whole hearts from Tpcn2−/− mice also showed reduced inotropic effects of isoproterenol and a reduced tendency for arrhythmias following acute β-adrenoreceptor stimulation. Hearts from Tpcn2−/− mice chronically exposed to isoproterenol showed less cardiac hypertrophy and increased threshold for arrhythmogenesis compared with WT controls. Electron microscopy showed that lysosomes form close contacts with the sarcoplasmic reticulum (separation ∼25 nm). We propose that Ca2+-signaling nanodomains between lysosomes and sarcoplasmic reticulum dependent on NAADP and TPC2 comprise an important element in β-adrenoreceptor signal transduction in cardiac myocytes. In summary, our observations define a role for NAADP and TPC2 at lysosomal/sarcoplasmic reticulum junctions as unexpected but major contributors in the acute actions of β-adrenergic signaling in the heart and also in stress pathways linking chronic stimulation of β-adrenoceptors to hypertrophy and associated arrhythmias.
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Affiliation(s)
- Rebecca A Capel
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Emma L Bolton
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Wee K Lin
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Daniel Aston
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Yanwen Wang
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Wei Liu
- the Faculty of Life Science, University of Manchester, Manchester M13 9NT, and
| | - Xin Wang
- the Faculty of Life Science, University of Manchester, Manchester M13 9NT, and
| | - Rebecca-Ann B Burton
- the Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Sherrington Road, Oxford OX1 3PT, United Kingdom
| | - Duncan Bloor-Young
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Kai-Ting Shade
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Margarida Ruas
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - John Parrington
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Grant C Churchill
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Ming Lei
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Antony Galione
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Derek A Terrar
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT,
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44
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Davidson SM, Foote K, Kunuthur S, Gosain R, Tan N, Tyser R, Zhao YJ, Graeff R, Ganesan A, Duchen MR, Patel S, Yellon DM. Inhibition of NAADP signalling on reperfusion protects the heart by preventing lethal calcium oscillations via two-pore channel 1 and opening of the mitochondrial permeability transition pore. Cardiovasc Res 2015; 108:357-66. [PMID: 26395965 PMCID: PMC4648198 DOI: 10.1093/cvr/cvv226] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 08/06/2015] [Indexed: 12/21/2022] Open
Abstract
Aims In the heart, a period of ischaemia followed by reperfusion evokes powerful cytosolic Ca2+ oscillations that can cause lethal cell injury. These signals represent attractive cardioprotective targets, but the underlying mechanisms of genesis are ill-defined. Here, we investigated the role of the second messenger nicotinic acid adenine dinucleotide phosphate (NAADP), which is known in several cell types to induce Ca2+ oscillations that initiate from acidic stores such as lysosomes, likely via two-pore channels (TPCs, TPC1 and 2). Methods and results An NAADP antagonist called Ned-K was developed by rational design based on a previously existing scaffold. Ned-K suppressed Ca2+ oscillations and dramatically protected cardiomyocytes from cell death in vitro after ischaemia and reoxygenation, preventing opening of the mitochondrial permeability transition pore. Ned-K profoundly decreased infarct size in mice in vivo. Transgenic mice lacking the endo-lysosomal TPC1 were also protected from injury. Conclusion NAADP signalling plays a major role in reperfusion-induced cell death and represents a potent pathway for protection against reperfusion injury.
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Affiliation(s)
- Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
| | - Kirsty Foote
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
| | - Suma Kunuthur
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
| | - Raj Gosain
- School of Chemistry, University of Southampton, Highfield, Southampton, UK
| | - Noah Tan
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
| | - Richard Tyser
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
| | - Yong Juan Zhao
- Department of Physiology, Li Ka Shing School of Medicine, The University of Hong Kong, Hong Kong, China
| | - Richard Graeff
- Department of Physiology, Li Ka Shing School of Medicine, The University of Hong Kong, Hong Kong, China
| | - A Ganesan
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, WC1E 6HX London, UK
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45
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Davis LC, Platt FM, Galione A. Preferential Coupling of the NAADP Pathway to Exocytosis in T-Cells. MESSENGER (LOS ANGELES, CALIF. : PRINT) 2015; 4:53-66. [PMID: 27330870 PMCID: PMC4910867 DOI: 10.1166/msr.2015.1040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A cytotoxic T-lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. However, these granules are more than reservoirs of secretory cytolytic proteins but may also serve as unique Ca2+ signaling hubs that autonomously generate their own signals for exocytosis. This review discusses a selective role for the Ca2+-mobilizing messenger, nicotinic acid adenine dinucleotide phosphate (NAADP) and its molecular targets, two-pore channels (TPCs), in stimulating exocytosis. Given that TPCs reside on the exocytotic granules themselves, these vesicles generate as well as respond to NAADP-dependent Ca2+ signals, which may have wider implications for stimulus-secretion coupling, vesicular fusion, and patho-physiology.
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Affiliation(s)
- Lianne C. Davis
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
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46
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Ruas M, Galione A, Parrington J. Two-Pore Channels: Lessons from Mutant Mouse Models. ACTA ACUST UNITED AC 2015; 4:4-22. [PMID: 27330869 DOI: 10.1166/msr.2015.1041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Recent interest in two-pore channels (TPCs) has resulted in a variety of studies dealing with the functional role and mechanism of action of these endo-lysosomal proteins in diverse physiological processes. With the availability of mouse lines harbouring mutant alleles for Tpcnl and/or Tpcn2 genes, several studies have made use of them to validate, consolidate and discover new roles for these channels not only at the cellular level but, importantly, also at the level of the whole organism. The different mutant mouse lines that have been used were derived from distinct genetic manipulation strategies, with the aim of knocking out expression of TPC proteins. However, the expression of different residual TPC sequences predicted to occur in these mutant mouse lines, together with the varied degree to which the effects on Tpcn expression have been studied, makes it important to assess the true knockout status of some of the lines. In this review we summarize these Tpcn mutant mouse lines with regard to their predicted effect on Tpcn expression and the extent to which they have been characterized. Additionally, we discuss how results derived from studies using these Tpcn mutant mouse lines have consolidated previously proposed roles for TPCs, such as mediators of NAADP signalling, endo-lysosomal functions, and pancreatic β cell physiology. We will also review how they have been instrumental in the assignment of new physiological roles for these cation channels in processes such as membrane electrical excitability, neoangiogenesis, viral infection and brown adipose tissue and heart function, revealing, in some cases, a specific contribution of a particular TPC isoform.
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Affiliation(s)
- Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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