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Tran QT, Tran VH, Sendler M, Doller J, Wiese M, Bolsmann R, Wilden A, Glaubitz J, Modenbach JM, Thiel FG, de Freitas Chama LL, Weiss FU, Lerch MM, Aghdassi AA. Role of Bile Acids and Bile Salts in Acute Pancreatitis: From the Experimental to Clinical Studies. Pancreas 2021; 50:3-11. [PMID: 33370017 PMCID: PMC7748038 DOI: 10.1097/mpa.0000000000001706] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022]
Abstract
ABSTRACT Acute pancreatitis (AP) is one of the most common gastroenterological disorders leading to hospitalization. It has long been debated whether biliary AP, about 30% to 50% of all cases, is induced by bile acids (BAs) when they reach the pancreas via reflux or via the systemic blood circulation.Besides their classical function in digestion, BAs have become an attractive research target because of their recently discovered property as signaling molecules. The underlying mechanisms of BAs have been investigated in various studies. Bile acids are internalized into acinar cells through specific G-protein-coupled BA receptor 1 and various transporters. They can further act via different receptors: the farnesoid X, ryanodine, and inositol triphosphate receptor. Bile acids induce a sustained Ca2+ influx from the endoplasmic reticulum and release of Ca2+ from acidic stores into the cytosol of acinar cells. The overload of intracellular Ca2+ results in mitochondrial depolarization and subsequent acinar cell necrosis. In addition, BAs have a biphasic effect on pancreatic ductal cells. A more detailed characterization of the mechanisms through which BAs contribute to the disease pathogenesis and severity will greatly improve our understanding of the underlying pathophysiology and may allow for the development of therapeutic and preventive strategies for gallstone-inducedAP.
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Affiliation(s)
- Quang Trung Tran
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
- Department of Internal Medicine, Hue University of Medicine and Pharmacy, Hue University, Hue, Vietnam
| | - Van Huy Tran
- Department of Internal Medicine, Hue University of Medicine and Pharmacy, Hue University, Hue, Vietnam
| | - Matthias Sendler
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Julia Doller
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Mats Wiese
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Robert Bolsmann
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Anika Wilden
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Juliane Glaubitz
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | | | | | | | - Frank Ulrich Weiss
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Markus M. Lerch
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Ali A. Aghdassi
- From the Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
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Cremer T, Neefjes J, Berlin I. The journey of Ca 2+ through the cell - pulsing through the network of ER membrane contact sites. J Cell Sci 2020; 133:133/24/jcs249136. [PMID: 33376155 DOI: 10.1242/jcs.249136] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Calcium is the third most abundant metal on earth, and the fundaments of its homeostasis date back to pre-eukaryotic life forms. In higher organisms, Ca2+ serves as a cofactor for a wide array of (enzymatic) interactions in diverse cellular contexts and constitutes the most important signaling entity in excitable cells. To enable responsive behavior, cytosolic Ca2+ concentrations are kept low through sequestration into organellar stores, particularly the endoplasmic reticulum (ER), but also mitochondria and lysosomes. Specific triggers are then used to instigate a local release of Ca2+ on demand. Here, communication between organelles comes into play, which is accomplished through intimate yet dynamic contacts, termed membrane contact sites (MCSs). The field of MCS biology in relation to cellular Ca2+ homeostasis has exploded in recent years. Taking advantage of this new wealth of knowledge, in this Review, we invite the reader on a journey of Ca2+ flux through the ER and its associated MCSs. New mechanistic insights and technological advances inform the narrative on Ca2+ acquisition and mobilization at these sites of communication between organelles, and guide the discussion of their consequences for cellular physiology.
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Affiliation(s)
- Tom Cremer
- Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
| | - Jacques Neefjes
- Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
| | - Ilana Berlin
- Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Einthovenweg 20, 2300RC Leiden, The Netherlands
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The role of Ca2+ signalling in the physiology and pathophysiology of exocrine pancreas. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Pallagi P, Madácsy T, Varga Á, Maléth J. Intracellular Ca 2+ Signalling in the Pathogenesis of Acute Pancreatitis: Recent Advances and Translational Perspectives. Int J Mol Sci 2020; 21:ijms21114005. [PMID: 32503336 PMCID: PMC7312053 DOI: 10.3390/ijms21114005] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/26/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
Intracellular Ca2+ signalling is a major signal transductional pathway in non-excitable cells, responsible for the regulation of a variety of physiological functions. In the secretory epithelial cells of the exocrine pancreas, such as acinar and ductal cells, intracellular Ca2+ elevation regulates digestive enzyme secretion in acini or fluid and ion secretion in ductal cells. Although Ca2+ is a uniquely versatile orchestrator of epithelial physiology, unregulated global elevation of the intracellular Ca2+ concentration is an early trigger for the development of acute pancreatitis (AP). Regardless of the aetiology, different forms of AP all exhibit sustained intracellular Ca2+ elevation as a common hallmark. The release of endoplasmic reticulum (ER) Ca2+ stores by toxins (such as bile acids or fatty acid ethyl esters (FAEEs)) or increased intrapancreatic pressure activates the influx of extracellular Ca2+ via the Orai1 Ca2+ channel, a process known as store-operated Ca2+ entry (SOCE). Intracellular Ca2+ overload can lead to premature activation of trypsinogen in pancreatic acinar cells and impaired fluid and HCO3- secretion in ductal cells. Increased and unbalanced reactive oxygen species (ROS) production caused by sustained Ca2+ elevation further contributes to cell dysfunction, leading to mitochondrial damage and cell death. Translational studies of AP identified several potential target molecules that can be modified to prevent intracellular Ca2+ overload. One of the most promising drugs, a selective inhibitor of the Orai1 channel that has been shown to inhibit extracellular Ca2+ influx and protect cells from injury, is currently being tested in clinical trials. In this review, we will summarise the recent advances in the field, with a special focus on the translational aspects of the basic findings.
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Affiliation(s)
- Petra Pallagi
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary; (P.P.); (T.M.); (Á.V.)
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
| | - Tamara Madácsy
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary; (P.P.); (T.M.); (Á.V.)
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
| | - Árpád Varga
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary; (P.P.); (T.M.); (Á.V.)
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
| | - József Maléth
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary; (P.P.); (T.M.); (Á.V.)
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
- Correspondence: or ; Tel.: +36-(62)-342-877 or +36-70-41-66500
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Okubo Y, Iino M. Visualization of astrocytic intracellular Ca 2+ mobilization. J Physiol 2019; 598:1671-1681. [PMID: 30825213 DOI: 10.1113/jp277609] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 02/06/2019] [Indexed: 11/08/2022] Open
Abstract
Astrocytes generate robust intracellular Ca2+ concentration changes (Ca2+ signals), which are assumed to regulate astrocytic functions that play crucial roles in the regulation of brain functions. One frequently used strategy for exploring the role of astrocytic Ca2+ signalling is the use of mice deficient in the type 2 inositol 1,4,5-trisphosphate receptor (IP3 R2). These IP3 R2-knockout (KO) mice are reportedly devoid of Ca2+ mobilization from the endoplasmic reticulum (ER) in astrocytes. However, they have shown no functional deficits in several studies, causing a heated debate as to the functional relevance of ER-mediated Ca2+ signalling in astrocytes. Recently, the assumption that Ca2+ mobilization from the ER is absent in IP3 R2-KO astrocytes has been re-evaluated using intraorganellar Ca2+ imaging techniques. The new results indicated that IP3 R2-independent Ca2+ release may generate Ca2+ nanodomains around the ER, which may help explain the absence of functional deficits in IP3 R2-KO mice.
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Affiliation(s)
- Yohei Okubo
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, 133-0033, Japan
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
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Mitochondrial junctions with cellular organelles: Ca 2+ signalling perspective. Pflugers Arch 2018; 470:1181-1192. [PMID: 29982949 PMCID: PMC6060751 DOI: 10.1007/s00424-018-2179-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 06/27/2018] [Accepted: 06/29/2018] [Indexed: 01/21/2023]
Abstract
Cellular organelles form multiple junctional complexes with one another and the emerging research area dealing with such structures and their functions is undergoing explosive growth. A new research journal named “Contact” has been recently established to facilitate the development of this research field. The current consensus is to define an organellar junction by the maximal distance between the participating organelles; and the gap of 30 nm or less is considered appropriate for classifying such structures as junctions or membrane contact sites. Ideally, the organellar junction should have a functional significance, i.e. facilitate transfer of calcium, sterols, phospholipids, iron and possibly other substances between the organelles (Carrasco and Meyer in Annu Rev Biochem 80:973–1000, 2011; Csordas et al. in Trends Cell Biol 28:523–540, 2018; Phillips and Voeltz in Nat Rev Mol Cell Biol 17:69–82, 2016; Prinz in J Cell Biol 205:759–769, 2014). It is also important to note that the junction is not just a result of a random organelle collision but have active and specific formation, stabilisation and disassembly mechanisms. The nature of these mechanisms and their role in physiology/pathophysiology are the main focus of an emerging research field. In this review, we will briefly describe junctional complexes formed by cellular organelles and then focus on the junctional complexes that are formed by mitochondria with other organelles and the role of these complexes in regulating Ca2+ signalling.
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Introduction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [PMID: 28900916 DOI: 10.1007/978-3-319-57732-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
In the title of this part of the book, the tail is wagging not just in a single dog but multiple dogs; in other words, a single process SOCE (tail) somehow involves a cross talk of (wagging) large and powerful organelle and cellular compartments (dogs). So how is this possible? Is this really necessary? Is the title actually appropriate?SOCE is a rather special process, it allows efficient signaling based on a ubiquitous second messenger (Ca2+) in multiple cell and tissue types, it has specific signaling modality (i.e., some downstream reactions depend specifically on SOCE and not just on global Ca2+ increase), it is vital for the normal functioning of multiple types of cells and tissues, and when misregulated it induces important pathological processes. The reader hopefully agree that such an important "tail" is more appropriate for a kangaroo than for a Chihuahua and that it has awesome wagging capacity.
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Abstract
The PMCA is an ATP-driven Ca2+ pump critical for the maintenance of low cytosolic calcium. The PMCA has an important but paradoxical role in cell death and survival. The PMCA can be differentially regulated by caspase/calpain cleavage. Glycolytic ATP supply may be sufficient to fuel the PMCA during metabolic stress. The ATP sensitivity of the PMCA can be regulated by acidic phospholipids.
The plasma membrane Ca2+-ATPase (PMCA) is a ubiquitously expressed, ATP-driven Ca2+ pump that is critical for maintaining low resting cytosolic Ca2+ ([Ca2+]i) in all eukaryotic cells. Since cytotoxic Ca2+ overload has such a central role in cell death, the PMCA represents an essential “linchpin” for the delicate balance between cell survival and cell death. In general, impaired PMCA activity and reduced PMCA expression leads to cytotoxic Ca2+ overload and Ca2+ dependent cell death, both apoptosis and necrosis, whereas maintenance of PMCA activity or PMCA overexpression is generally accepted as being cytoprotective. However, the PMCA has a paradoxical role in cell death depending on the cell type and cellular context. The PMCA can be differentially regulated by Ca2+-dependent proteolysis, can be maintained by a localised glycolytic ATP supply, even in the face of global ATP depletion, and can be profoundly affected by the specific phospholipid environment that it sits within the membrane. The major focus of this review is to highlight some of the controversies surrounding the paradoxical role of the PMCA in cell death and survival, challenging the conventional view of ATP-dependent regulation of the PMCA and how this might influence cell fate.
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Affiliation(s)
- Jason I E Bruce
- Division of Molecular & Clinical Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, United Kingdom.
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Okeke E, Dingsdale H, Parker T, Voronina S, Tepikin AV. Endoplasmic reticulum-plasma membrane junctions: structure, function and dynamics. J Physiol 2016; 594:2837-47. [PMID: 26939537 DOI: 10.1113/jp271142] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/13/2016] [Indexed: 12/20/2022] Open
Abstract
Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are contact sites between the ER and the PM; the distance between the two organelles in the junctions is below 40 nm and the membranes are connected by protein tethers. A number of molecular tools and technical approaches have been recently developed to visualise, modify and characterise properties of ER-PM junctions. The junctions serve as the platforms for lipid exchange between the organelles and for cell signalling, notably Ca(2+) and cAMP signalling. Vice versa, signalling events regulate the development and properties of the junctions. Two Ca(2+) -dependent mechanisms of de novo formation of ER-PM junctions have been recently described and characterised. The junction-forming proteins and lipids are currently the focus of vigorous investigation. Junctions can be relatively short-lived and simple structures, forming and dissolving on the time scale of a few minutes. However, complex, sophisticated and multifunctional ER-PM junctions, capable of attracting numerous protein residents and other cellular organelles, have been described in some cell types. The road from simplicity to complexity, i.e. the transformation from simple 'nascent' ER-PM junctions to advanced stable multiorganellar complexes, is likely to become an attractive research avenue for current and future junctologists. Another area of considerable research interest is the downstream cellular processes that can be activated by specific local signalling events in the ER-PM junctions. Studies of the cell physiology and indeed pathophysiology of ER-PM junctions have already produced some surprising discoveries, likely to expand with advances in our understanding of these remarkable organellar contact sites.
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Affiliation(s)
- Emmanuel Okeke
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Hayley Dingsdale
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Tony Parker
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Svetlana Voronina
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alexei V Tepikin
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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Geyer N, Diszházi G, Csernoch L, Jóna I, Almássy J. Bile acids activate ryanodine receptors in pancreatic acinar cells via a direct allosteric mechanism. Cell Calcium 2015; 58:160-70. [DOI: 10.1016/j.ceca.2015.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/10/2015] [Accepted: 03/30/2015] [Indexed: 12/12/2022]
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Samad A, James A, Wong J, Mankad P, Whitehouse J, Patel W, Alves-Simoes M, Siriwardena AK, Bruce JIE. Insulin protects pancreatic acinar cells from palmitoleic acid-induced cellular injury. J Biol Chem 2014; 289:23582-95. [PMID: 24993827 PMCID: PMC4156068 DOI: 10.1074/jbc.m114.589440] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acute pancreatitis is a serious and sometimes fatal inflammatory disease where the pancreas digests itself. The non-oxidative ethanol metabolites palmitoleic acid (POA) and POA-ethylester (POAEE) are reported to induce pancreatitis caused by impaired mitochondrial metabolism, cytosolic Ca2+ ([Ca2+]i) overload and necrosis of pancreatic acinar cells. Metabolism and [Ca2+]i are linked critically by the ATP-driven plasma membrane Ca2+-ATPase (PMCA) important for maintaining low resting [Ca2+]i. The aim of the current study was to test the protective effects of insulin on cellular injury induced by the pancreatitis-inducing agents, ethanol, POA, and POAEE. Rat pancreatic acinar cells were isolated by collagenase digestion and [Ca2+]i was measured by fura-2 imaging. An in situ [Ca2+]i clearance assay was used to assess PMCA activity. Magnesium green (MgGreen) and a luciferase-based ATP kit were used to assess cellular ATP depletion. Ethanol (100 mm) and POAEE (100 μm) induced a small but irreversible Ca2+ overload response but had no significant effect on PMCA activity. POA (50–100 μm) induced a robust Ca2+ overload, ATP depletion, inhibited PMCA activity, and consequently induced necrosis. Insulin pretreatment (100 nm for 30 min) prevented the POA-induced Ca2+ overload, ATP depletion, inhibition of the PMCA, and necrosis. Moreover, the insulin-mediated protection of the POA-induced Ca2+ overload was partially prevented by the phosphoinositide-3-kinase (PI3K) inhibitor, LY294002. These data provide the first evidence that insulin directly protects pancreatic acinar cell injury induced by bona fide pancreatitis-inducing agents, such as POA. This may have important therapeutic implications for the treatment of pancreatitis.
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Affiliation(s)
- Aysha Samad
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - Andrew James
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - James Wong
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - Parini Mankad
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - John Whitehouse
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - Waseema Patel
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - Marta Alves-Simoes
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
| | - Ajith K Siriwardena
- the Hepatobiliary Surgery Unit, Manchester Royal Infirmary, M13 9WL Manchester, United Kingdom
| | - Jason I E Bruce
- From the Faculty of Life Sciences, The University of Manchester, M13 9NT Manchester and
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The role of pancreatic ductal secretion in protection against acute pancreatitis in mice*. Crit Care Med 2014; 42:e177-88. [PMID: 24368347 DOI: 10.1097/ccm.0000000000000101] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVES A common potentially fatal disease of the pancreas is acute pancreatitis, for which there is no treatment. Most studies of this disorder focus on the damage to acinar cells since they are assumed to be the primary target of multiple stressors affecting the pancreas. However, increasing evidence suggests that the ducts may also have a crucial role in induction of the disease. To test this hypothesis, we sought to determine the specific role of the duct in the induction of acute pancreatitis using well-established disease models and mice with deletion of the Na/H exchanger regulatory factor-1 that have selectively impaired ductal function. DESIGN Randomized animal study. SETTING Animal research laboratory. SUBJECTS Wild-type and Na/H exchanger regulatory factor-1 knockout mice. INTERVENTIONS Acute necrotizing pancreatitis was induced by i.p. administration of cerulein or by intraductal administration of sodium taurocholate. The pancreatic expression of Na/H exchanger regulatory factor-1 and cystic fibrosis transmembrane conductance regulator (a key player in the control of ductal secretion) was analyzed by immunohistochemistry. In vivo pancreatic ductal secretion was studied in anesthetized mice. Functions of pancreatic acinar and ductal cells as well as inflammatory cells were analyzed in vitro. MEASUREMENTS AND MAIN RESULTS Deletion of Na/H exchanger regulatory factor-1 resulted in gross mislocalization of cystic fibrosis transmembrane conductance regulator, causing marked reduction in pancreatic ductal fluid and bicarbonate secretion. Importantly, deletion of Na/H exchanger regulatory factor-1 had no deleterious effect on functions of acinar and inflammatory cells. Deletion of Na/H exchanger regulatory factor-1, which specifically impaired ductal function, increased the severity of acute pancreatitis in the two mouse models tested. CONCLUSIONS Our findings provide the first direct evidence for the crucial role of ductal secretion in protecting the pancreas from acute pancreatitis and strongly suggest that improved ductal function should be an important modality in prevention and treatment of the disease.
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Voronina S, Okeke E, Parker T, Tepikin A. How to win ATP and influence Ca(2+) signaling. Cell Calcium 2014; 55:131-8. [PMID: 24613709 DOI: 10.1016/j.ceca.2014.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 12/11/2022]
Abstract
This brief review discusses recent advances in studies of mitochondrial Ca(2+) signaling and considers how the relationships between mitochondria and Ca(2+) responses are shaped in secretory epithelial cells. Perhaps the more precise title of this review could have been "How to win ATP and influence Ca(2+) signaling in secretory epithelium with emphasis on exocrine secretory cells and specific focus on pancreatic acinar cells". But "brevity is a virtue" and the authors hope that many of the mechanisms discussed are general and applicable to other tissues and cell types. Among these mechanisms are mitochondrial regulation of Ca(2+) entry and the role of mitochondria in the formation of localized Ca(2+) responses. The roles of Ca(2+) signaling in the physiological adjustment of bioenergetics and in mitochondrial damage are also briefly discussed.
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Affiliation(s)
- Svetlana Voronina
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - Emmanuel Okeke
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - Tony Parker
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - Alexei Tepikin
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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Calcium signaling in pancreatic ductal epithelial cells: an old friend and a nasty enemy. Cell Calcium 2014; 55:337-45. [PMID: 24602604 DOI: 10.1016/j.ceca.2014.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 12/20/2022]
Abstract
Ductal epithelial cells of the exocrine pancreas secrete HCO3(-) rich, alkaline pancreatic juice, which maintains the intraluminal pH and washes the digestive enzymes out from the ductal system. Importantly, damage of this secretory process can lead to pancreatic diseases such as acute and chronic pancreatitis. Intracellular Ca(2+) signaling plays a central role in the physiological regulation of HCO3(-) secretion, however uncontrolled Ca(2+) release can lead to intracellular Ca(2+) overload and toxicity, including mitochondrial damage and impaired ATP production. Recent findings suggest that the most common pathogenic factors leading to acute pancreatitis, such as bile acids, or ethanol and ethanol metabolites can evoke different types of intracellular Ca(2+) signals, which can stimulate or inhibit ductal HCO3(-) secretion. Therefore, understanding the intracellular Ca(2+) pathways and the mechanisms which can switch a good signal to a bad signal in pancreatic ductal epithelial cells are crucially important. This review summarizes the variety of Ca(2+) signals both in physiological and pathophysiological aspects and highlight molecular targets which may strengthen our old friend or release our nasty enemy.
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James AD, Chan A, Erice O, Siriwardena AK, Bruce JIE. Glycolytic ATP fuels the plasma membrane calcium pump critical for pancreatic cancer cell survival. J Biol Chem 2013; 288:36007-19. [PMID: 24158437 PMCID: PMC3861649 DOI: 10.1074/jbc.m113.502948] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Pancreatic cancer is an aggressive cancer with poor prognosis and limited treatment options. Cancer cells rapidly proliferate and are resistant to cell death due, in part, to a shift from mitochondrial metabolism to glycolysis. We hypothesized that this shift is important in regulating cytosolic Ca2+ ([Ca2+]i), as the ATP-dependent plasma membrane Ca2+ ATPase (PMCA) is critical for maintaining low [Ca2+]i and thus cell survival. The present study aimed to determine the relative contribution of mitochondrial versus glycolytic ATP in fuelling the PMCA in human pancreatic cancer cells. We report that glycolytic inhibition induced profound ATP depletion, PMCA inhibition, [Ca2+]i overload, and cell death in PANC1 and MIA PaCa-2 cells. Conversely, inhibition of mitochondrial metabolism had no effect, suggesting that glycolytic ATP is critical for [Ca2+]i homeostasis and thus survival. Targeting the glycolytic regulation of the PMCA may, therefore, be an effective strategy for selectively killing pancreatic cancer while sparing healthy cells.
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Affiliation(s)
- Andrew D James
- From the Faculty of Life Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, United Kingdom and
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Cytosolic calcium regulation in rat afferent vagal neurons during anoxia. Cell Calcium 2013; 54:416-27. [PMID: 24189167 DOI: 10.1016/j.ceca.2013.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/30/2013] [Accepted: 10/06/2013] [Indexed: 12/12/2022]
Abstract
Sensory neurons are able to detect tissue ischaemia and both transmit information to the brainstem as well as release local vasoactive mediators. Their ability to sense tissue ischaemia is assumed to be primarily mediated through proton sensing ion channels, lack of oxygen however may also affect sensory neuron function. In this study we investigated the effects of anoxia on isolated capsaicin sensitive neurons from rat nodose ganglion. Acute anoxia triggered a reversible increase in [Ca2+]i that was mainly due to Ca2+-efflux from FCCP sensitive stores and from caffeine and CPA sensitive ER stores. Prolonged anoxia resulted in complete depletion of ER Ca2+-stores. Mitochondria were partially depolarised by acute anoxia but mitochondrial Ca2+-uptake/buffering during voltage-gated Ca2+-influx was unaffected. The process of Ca2+-release from mitochondria and cytosolic Ca2+-clearance following Ca2+ influx was however significantly slowed. Anoxia was also found to inhibit SERCA activity and, to a lesser extent, PMCA activity. Hence, anoxia has multiple influences on [Ca2+]i homeostasis in vagal afferent neurons, including depression of ATP-driven Ca2+-pumps, modulation of the kinetics of mitochondrial Ca2+ buffering/release and Ca2+-release from, and depletion of, internal Ca2+-stores. These effects are likely to influence sensory neuronal function during ischaemia.
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The Exocrine Pancreas: The Acinar-Ductal Tango in Physiology and Pathophysiology. Rev Physiol Biochem Pharmacol 2013; 165:1-30. [DOI: 10.1007/112_2013_14] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Cellular geography of IP3 receptors, STIM and Orai: a lesson from secretory epithelial cells. Biochem Soc Trans 2012; 40:108-11. [PMID: 22260674 DOI: 10.1042/bst20110639] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pancreatic acinar cells exhibit a remarkable polarization of Ca2+ release and Ca2+ influx mechanisms. In the present brief review, we discuss the localization of channels responsible for Ca2+ release [mainly IP3 (inositol 1,4,5-trisphosphate) receptors] and proteins responsible for SOCE (store-operated Ca2+ entry). We also place these Ca2+-transporting mechanisms on the map of cellular organelles in pancreatic acinar cells, and discuss the physiological implications of the cellular geography of Ca2+ signalling. Finally, we highlight some unresolved questions stemming from recent observations of co-localization and co-immunoprecipitation of IP3 receptors with Orai channels in the apical (secretory) region of pancreatic acinar cells.
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Voronina S, Tepikin A. Mitochondrial calcium in the life and death of exocrine secretory cells. Cell Calcium 2012; 52:86-92. [PMID: 22571865 DOI: 10.1016/j.ceca.2012.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/26/2012] [Accepted: 03/27/2012] [Indexed: 01/11/2023]
Abstract
The remarkable recent discoveries of the proteins mediating mitochondrial Ca(2+) transport (reviewed in this issue) provide an exciting opportunity to utilise this new knowledge to improve our fundamental understanding of relationships between Ca(2+) signalling and bioenergetics and, importantly, to improve the understanding of diseases in which Ca(2+) toxicity and mitochondrial malfunction play a crucial role. Ca(2+) is an important activator of exocrine secretion, a regulator of the bioenergetics of exocrine cells and a contributor to exocrine cell damage. Exocrine secretory cells, exocrine tissues and diseases affecting exocrine glands (like Sjögren's syndrome and acute pancreatitis) will, therefore, provide worthy research areas for the application of this new knowledge of the Ca(2+) transport mechanisms in mitochondria.
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Affiliation(s)
- Svetlana Voronina
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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Abstract
Pancreatic cells contain specialised stores for ATP. Purinergic receptors (P2 and P1) and ecto-nucleotidases are expressed in both endocrine and exocrine calls, as well as in stromal cells. The pancreas, especially the endocrine cells, were an early target for the actions of ATP. After the historical perspective of purinergic signalling in the pancreas, the focus of this review will be the physiological functions of purinergic signalling in the regulation of both endocrine and exocrine pancreas. Next, we will consider possible interaction between purinergic signalling and other regulatory systems and their relation to nutrient homeostasis and cell survival. The pancreas is an organ exhibiting several serious diseases - cystic fibrosis, pancreatitis, pancreatic cancer and diabetes - and some are associated with changes in life-style and are increasing in incidence. There is upcoming evidence for the role of purinergic signalling in the pathophysiology of the pancreas, and the new challenge is to understand how it is integrated with other pathological processes.
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Affiliation(s)
- G Burnstock
- University College Medical School, Autonomic Neuroscience Centre, Rowland Hill Street, London NW3 2PF, UK.
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Park HS, Betzenhauser MJ, Zhang Y, Yule DI. Regulation of Ca²⁺ release through inositol 1,4,5-trisphosphate receptors by adenine nucleotides in parotid acinar cells. Am J Physiol Gastrointest Liver Physiol 2012; 302:G97-G104. [PMID: 21960523 PMCID: PMC3345966 DOI: 10.1152/ajpgi.00328.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Secretagogue-stimulated intracellular Ca(2+) signals are fundamentally important for initiating the secretion of the fluid and ion component of saliva from parotid acinar cells. The Ca(2+) signals have characteristic spatial and temporal characteristics, which are defined by the specific properties of Ca(2+) release mediated by inositol 1,4,5-trisphosphate receptors (InsP(3)R). In this study we have investigated the role of adenine nucleotides in modulating Ca(2+) release in mouse parotid acinar cells. In permeabilized cells, the Ca(2+) release rate induced by submaximal [InsP(3)] was increased by 5 mM ATP. Enhanced Ca(2+) release was not observed at saturating [InsP(3)]. The EC(50) for the augmented Ca(2+) release was ∼8 μM ATP. The effect was mimicked by nonhydrolysable ATP analogs. ADP and AMP also potentiated Ca(2+) release but were less potent than ATP. In acini isolated from InsP(3)R-2-null transgenic animals, the rate of Ca(2+) release was decreased under all conditions but now enhanced by ATP at all [InsP(3)]. In addition the EC(50) for ATP potentiation increased to ∼500 μM. These characteristics are consistent with the properties of the InsP(3)R-2 dominating the overall features of InsP(3)R-induced Ca(2+) release despite the expression of all isoforms. Finally, Ca(2+) signals were measured in intact parotid lobules by multiphoton microscopy. Consistent with the release data, carbachol-stimulated Ca(2+) signals were reduced in lobules exposed to experimental hypoxia compared with control lobules only at submaximal concentrations. Adenine nucleotide modulation of InsP(3)R in parotid acinar cells likely contributes to the properties of Ca(2+) signals in physiological and pathological conditions.
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Affiliation(s)
- Hyung Seo Park
- University of Rochester Medical Center, Department of Pharmacology and Physiology, University of Rochester, Rochester, New York
| | - Matthew J. Betzenhauser
- University of Rochester Medical Center, Department of Pharmacology and Physiology, University of Rochester, Rochester, New York
| | - Yu Zhang
- University of Rochester Medical Center, Department of Pharmacology and Physiology, University of Rochester, Rochester, New York
| | - David I. Yule
- University of Rochester Medical Center, Department of Pharmacology and Physiology, University of Rochester, Rochester, New York
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22
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Abstract
Orai1 proteins have been recently identified as subunits of SOCE (store-operated Ca2+ entry) channels. In primary isolated PACs (pancreatic acinar cells), Orai1 showed remarkable co-localization and co-immunoprecipitation with all three subtypes of IP3Rs (InsP3 receptors). The co-localization between Orai1 and IP3Rs was restricted to the apical part of PACs. Neither co-localization nor co-immunoprecipitation was affected by Ca2+ store depletion. Importantly we also characterized Orai1 in basal and lateral membranes of PACs. The basal and lateral membranes of PACs have been shown previously to accumulate STIM1 (stromal interaction molecule 1) puncta as a result of Ca2+ store depletion. We therefore conclude that these polarized secretory cells contain two pools of Orai1: an apical pool that interacts with IP3Rs and a basolateral pool that interacts with STIM1 following the Ca2+ store depletion. Experiments on IP3R knockout animals demonstrated that the apical Orai1 localization does not require IP3Rs and that IP3Rs are not necessary for the activation of SOCE. However, the InsP3-releasing secretagogue ACh (acetylcholine) produced a negative modulatory effect on SOCE, suggesting that activated IP3Rs could have an inhibitory effect on this Ca2+ entry mechanism.
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Abstract
PURPOSE OF REVIEW This review identifies and puts into context the recent articles which have advanced understanding of the functions of pancreatic acinar cells and the mechanisms by which these functions are regulated. RECENT FINDINGS Receptors present on acinar cells, particularly those for cholecystokinin and secretin, have been better characterized as to the molecular nature of the ligand-receptor interaction. Other reports have described the potential regulation of acinar cells by GLP-1 and cannabinoids. Intracellular Ca2+ signaling remains at the center of stimulus secretion coupling and its regulation has been further defined. Recent studies have identified specific channels mediating Ca2+ release from intracellular stores and influx across the plasma membrane. Work downstream of intracellular mediators has focused on molecular mechanisms of exocytosis particularly involving small G proteins, SNARE proteins and chaperone molecules. In addition to secretion, recent studies have further defined the regulation of pancreatic growth both in adaptive regulation to diet and hormones in the regeneration that occurs after pancreatic damage. Lineage tracing has been used to show the contribution of different cell types. The importance of specific amino acids as signaling molecules to activate the mTOR pathway is being elucidated. SUMMARY Understanding the mechanisms that regulate pancreatic acinar cell function is contributing to knowledge of normal pancreatic function and alterations in disease.
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Bruce JI. Plasma membrane calcium pump regulation by metabolic stress. World J Biol Chem 2010; 1:221-8. [PMID: 21537477 PMCID: PMC3083969 DOI: 10.4331/wjbc.v1.i7.221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 06/30/2010] [Accepted: 07/07/2010] [Indexed: 02/05/2023] Open
Abstract
The plasma membrane Ca2+-ATPase (PMCA) is an ATP-driven pump that is critical for the maintenance of low resting [Ca2+]i in all eukaryotic cells. Metabolic stress, either due to inhibition of mitochondrial or glycolytic metabolism, has the capacity to cause ATP depletion and thus inhibit PMCA activity. This has potentially fatal consequences, particularly for non-excitable cells in which the PMCA is the major Ca2+ efflux pathway. This is because inhibition of the PMCA inevitably leads to cytosolic Ca2+ overload and the consequent cell death. However, the relationship between metabolic stress, ATP depletion and inhibition of the PMCA is not as simple as one would have originally predicted. There is increasing evidence that metabolic stress can lead to the inhibition of PMCA activity independent of ATP or prior to substantial ATP depletion. In particular, there is evidence that the PMCA has its own glycolytic ATP supply that can fuel the PMCA in the face of impaired mitochondrial function. Moreover, membrane phospholipids, mitochondrial membrane potential, caspase/calpain cleavage and oxidative stress have all been implicated in metabolic stress-induced inhibition of the PMCA. The major focus of this review is to challenge the conventional view of ATP-dependent regulation of the PMCA and bring together some of the alternative or additional mechanisms by which metabolic stress impairs PMCA activity resulting in cytosolic Ca2+ overload and cytotoxicity.
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Affiliation(s)
- Jason Ie Bruce
- Jason IE Bruce, Faculty of Life Sciences, The University of Manchester, Manchester M13 9NT, United Kingdom
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25
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Voronina S, Barrow S, Simpson A, Gerasimenko O, da Silva Xavier G, Rutter G, Petersen O, Tepikin AV. Dynamic changes in cytosolic and mitochondrial ATP levels in pancreatic acinar cells. Gastroenterology 2010; 138:1976-87. [PMID: 20102715 PMCID: PMC6101211 DOI: 10.1053/j.gastro.2010.01.037] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 12/17/2009] [Accepted: 01/21/2010] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS Previous studies of pancreatic acinar cells characterized the effects of Ca(2+)-releasing secretagogues and substances, inducing acute pancreatitis on mitochondrial Ca(2+), transmembrane potential, and NAD(P)H, but dynamic measurements of the crucial intracellular adenosine triphosphate (ATP) levels have not been reported. Here we characterized the effects of these agents on ATP levels in the cytosol and mitochondria. METHODS ATP levels were monitored using cytosolic- or mitochondrial-targeted luciferases. RESULTS Inhibition of oxidative phosphorylation produced a substantial decrease in cytosolic ATP comparable to that induced by inhibition of glycolysis. Cholecystokinin-8 (CCK) increased cytosolic ATP in spite of accelerating ATP consumption. Acetylcholine, caerulein, and bombesin had similar effect. A bile acid, taurolithocholic acid 3-sulfate (TLC-S); a fatty acid, palmitoleic acid (POA); and palmitoleic acid ethyl ester (POAEE) reduced cytosolic ATP. The ATP decrease in response to these substances was observed in cells with intact or inhibited oxidative phosphorylation. TLC-S, POA, and POAEE reduced mitochondrial ATP, whereas physiological CCK increased mitochondrial ATP. Supramaximal CCK produced a biphasic response composed of a small initial decline followed by a stronger increase. CONCLUSIONS Both glycolysis and oxidative phosphorylation make substantial contributions to ATP production in acinar cells. Ca(2+)-releasing secretagogues increased ATP level in the cytosol and mitochondria of intact isolated cells. TLC-S, POA, and POAEE reduced cytosolic and mitochondrial ATP. When cells rely on nonoxidative ATP production, secretagogues as well as TLC-S, POA, and POAEE all diminish cytosolic ATP levels.
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Affiliation(s)
- Svetlana Voronina
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Stephanie Barrow
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alec Simpson
- Department of Human Anatomy and Cell Biology, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Oleg Gerasimenko
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Gabriela da Silva Xavier
- Section of Cell Biology, Division of Medicine, Imperial College, London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, UK
| | - Guy Rutter
- Section of Cell Biology, Division of Medicine, Imperial College, London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, UK
| | - Ole Petersen
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alexei V. Tepikin
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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26
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27
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Petersen OH, Tepikin AV, Gerasimenko JV, Gerasimenko OV, Sutton R, Criddle DN. Fatty acids, alcohol and fatty acid ethyl esters: toxic Ca2+ signal generation and pancreatitis. Cell Calcium 2009; 45:634-42. [PMID: 19327825 DOI: 10.1016/j.ceca.2009.02.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 01/11/2023]
Abstract
Pancreatitis, a potentially fatal disease in which the pancreas digests itself as well as its surroundings, is a well recognized complication of hyperlipidemia. Fatty acids have toxic effects on pancreatic acinar cells and these are mediated by large sustained elevations of the cytosolic Ca(2+) concentration. An important component of the effect of fatty acids is due to inhibition of mitochondrial function and subsequent ATP depletion, which reduces the operation of Ca(2+)-activated ATPases in both the endoplasmic reticulum and the plasma membrane. One of the main causes of pancreatitis is alcohol abuse. Whereas the effects of even high alcohol concentrations on isolated pancreatic acinar cells are variable and often small, fatty acid ethyl esters--synthesized by combination of alcohol and fatty acids--consistently evoke major Ca(2+) release from intracellular stores, subsequently opening Ca(2+) entry channels in the plasma membrane. The crucial trigger for pancreatic autodigestion is intracellular trypsin activation. Although there is still uncertainty about the exact molecular mechanism by which this Ca(2+)-dependent process occurs, progress has been made in identifying a subcellular compartment--namely acid post-exocytotic endocytic vacuoles--in which this activation takes place.
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Affiliation(s)
- O H Petersen
- MRC Secretory Control Research Group, Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool, UK.
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28
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Walsh C, Barrow S, Voronina S, Chvanov M, Petersen OH, Tepikin A. Modulation of calcium signalling by mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1374-82. [PMID: 19344663 DOI: 10.1016/j.bbabio.2009.01.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 02/07/2023]
Abstract
In this review we will attempt to summarise the complex and sometimes contradictory effects that mitochondria have on different forms of calcium signalling. Mitochondria can influence Ca(2+) signalling indirectly by changing the concentration of ATP, NAD(P)H, pyruvate and reactive oxygen species - which in turn modulate components of the Ca(2+) signalling machinery i.e. buffering, release from internal stores, influx from the extracellular solution, uptake into cellular organelles and extrusion by plasma membrane Ca(2+) pumps. Mitochondria can directly influence the calcium concentration in the cytosol of the cell by importing Ca(2+) via the mitochondrial Ca(2+) uniporter or transporting Ca(2+) from the interior of the organelle into the cytosol by means of Na+/Ca(2+) or H+/Ca(2+) exchangers. Considerable progress in understanding the relationship between Ca(2+) signalling cascades and mitochondrial physiology has been accumulated over the last few years due to the development of more advanced optical techniques and electrophysiological approaches.
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Affiliation(s)
- Ciara Walsh
- Department of Physiology, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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29
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Voronina S, Sherwood M, Barrow S, Dolman N, Conant A, Tepikin A. Downstream from calcium signalling: mitochondria, vacuoles and pancreatic acinar cell damage. Acta Physiol (Oxf) 2009; 195:161-9. [PMID: 18983443 DOI: 10.1111/j.1748-1716.2008.01931.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ca(2+) is one of the most ancient and ubiquitous second messengers. Highly polarized pancreatic acinar cells serve as an important cellular model for studies of Ca(2+) signalling and homeostasis. Downstream effects of Ca(2+) signalling have been and continue to be an important research avenue. The primary functions regulated by Ca(2+) in pancreatic acinar cells--exocytotic secretion and fluid secretion--have been defined and extensively characterized in the second part of the last century. The role of cytosolic Ca(2+) in cellular pathology and the related question of the interplay between Ca(2+) signalling and bioenergetics are important current research lines in our and other laboratories. Recent findings in these interwoven research areas are discussed in the current review.
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Affiliation(s)
- S Voronina
- Physiological Laboratory, University of Liverpool, Liverpool, UK
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30
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Baggaley EM, Elliott AC, Bruce JIE. Oxidant-induced inhibition of the plasma membrane Ca2+-ATPase in pancreatic acinar cells: role of the mitochondria. Am J Physiol Cell Physiol 2008; 295:C1247-60. [PMID: 18787078 DOI: 10.1152/ajpcell.00083.2008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Impairment of the normal spatiotemporal pattern of intracellular Ca(2+) ([Ca(2+)](i)) signaling, and in particular, the transition to an irreversible "Ca(2+) overload" response, has been implicated in various pathophysiological states. In some diseases, including pancreatitis, oxidative stress has been suggested to mediate this Ca(2+) overload and the associated cell injury. We have previously demonstrated that oxidative stress with hydrogen peroxide (H(2)O(2)) evokes a Ca(2+) overload response and inhibition of plasma membrane Ca(2+)-ATPase (PMCA) in rat pancreatic acinar cells (Bruce JI and Elliott AC. Am J Physiol Cell Physiol 293: C938-C950, 2007). The aim of the present study was to further examine this oxidant-impaired inhibition of the PMCA, focusing on the role of the mitochondria. Using a [Ca(2+)](i) clearance assay in which mitochondrial Ca(2+) uptake was blocked with Ru-360, H(2)O(2) (50 microM-1 mM) markedly inhibited the PMCA activity. This H(2)O(2)-induced inhibition of the PMCA correlated with mitochondrial depolarization (assessed using tetramethylrhodamine methylester fluorescence) but could occur without significant ATP depletion (assessed using Magnesium Green fluorescence). The H(2)O(2)-induced PMCA inhibition was sensitive to the mitochondrial permeability transition pore (mPTP) inhibitors, cyclosporin-A and bongkrekic acid. These data suggest that oxidant-induced opening of the mPTP and mitochondrial depolarization may lead to an inhibition of the PMCA that is independent of mitochondrial Ca(2+) handling and ATP depletion, and we speculate that this may involve the release of a mitochondrial factor. Such a phenomenon may be responsible for the Ca(2+) overload response, and for the transition between apoptotic and necrotic cell death thought to be important in many disease states.
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Affiliation(s)
- Erin M Baggaley
- Faculty of Life Sciences, 2nd Floor Core Technology Facility, 46 Grafton St., Univ. of Manchester, Manchester M13 9NT, UK
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31
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Abstract
PURPOSE OF REVIEW This timely review will focus on clinical and basic science studies that have greatly advanced our knowledge of the molecular mechanisms of both acute pancreatitis and chronic pancreatitis over the last year. RECENT FINDINGS Animal models of both severe acute pancreatitis and chronic pancreatitis have recently been developed. Several unexpected protective mechanisms, mediated by the protease activated receptor 2 and heat shock protein 70, have been described. A genetic study suggested that polymorphisms in toll-like receptor-4 might affect the risk of developing infections in acute pancreatitis. Studies of chronic pancreatitis have shown that specific neural receptors, transient receptor potential vanilloid subtype 1, mediate pain responses in a model of chronic pancreatitis. The pancreatic zymogen, chymotrypsin C, can degrade pathologically activated trypsin in the acinar cell. Inactivating mutations in chymotrypsin C have been reported to predispose to the development of chronic pancreatitis, especially in those who are prone to alcohol abuse. SUMMARY The implications of the last year's findings are widespread. Improved animal models of acute pancreatitis and chronic pancreatitis will be critical for performing pilot studies of therapy. A greater understanding of genetic factors and pain responses could lead to potential treatments. This review will first discuss issues related to acute pancreatitis, and then conclude with studies most relevant to chronic disease.
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Park HS, Betzenhauser MJ, Won JH, Chen J, Yule DI. The type 2 inositol (1,4,5)-trisphosphate (InsP3) receptor determines the sensitivity of InsP3-induced Ca2+ release to ATP in pancreatic acinar cells. J Biol Chem 2008; 283:26081-8. [PMID: 18658132 DOI: 10.1074/jbc.m804184200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calcium release through inositol (1,4,5)-trisphosphate receptors (InsP(3)R) is the primary signal driving digestive enzyme and fluid secretion from pancreatic acinar cells. The type 2 (InsP(3)R2) and type 3 (InsP(3)R3) InsP(3)R are the predominant isoforms expressed in acinar cells and are required for proper exocrine gland function. Both InsP(3)R2 and InsP(3)R3 are positively regulated by cytosolic ATP, but InsP(3)R2 is 10-fold more sensitive than InsP(3)R3 to this form of modulation. In this study, we examined the role of InsP(3)R2 in setting the sensitivity of InsP(3)-induced Ca(2+) release (IICR) to ATP in pancreatic acinar cells. IICR was measured in permeabilized acinar cells from wild-type (WT) and InsP(3)R2 knock-out (KO) mice. ATP augmented IICR from WT pancreatic cells with an EC(50) of 38 microm. However, the EC(50) was 10-fold higher in acinar cells isolated from InsP(3)R2-KO mice, indicating a role for InsP(3)R2 in setting the sensitivity of IICR to ATP. Consistent with this idea, heterologous expression of InsP(3)R2 in RinM5F cells, which natively express predominately InsP(3)R3, increased the sensitivity of IICR to ATP. Depletion of ATP attenuated agonist-induced Ca(2+) signaling in WT pancreatic acinar cells. This effect was more profound in acinar cells prepared from InsP(3)R2-KO mice. These data suggest that the sensitivity of IICR to ATP depletion is regulated by the particular complement of InsP(3)R expressed in an individual cell. The effects of metabolic stress on intracellular Ca(2+) signals can therefore be determined by the relative amount of InsP(3)R2 expressed in cells.
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Affiliation(s)
- Hyung Seo Park
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York 14642, USA
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Chvanov M, Walsh CM, Haynes LP, Voronina SG, Lur G, Gerasimenko OV, Barraclough R, Rudland PS, Petersen OH, Burgoyne RD, Tepikin AV. ATP depletion induces translocation of STIM1 to puncta and formation of STIM1-ORAI1 clusters: translocation and re-translocation of STIM1 does not require ATP. Pflugers Arch 2008; 457:505-17. [PMID: 18542992 PMCID: PMC2770109 DOI: 10.1007/s00424-008-0529-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 05/08/2008] [Indexed: 12/27/2022]
Abstract
Depletion of the endoplasmic reticulum (ER) calcium store triggers translocation of stromal interacting molecule one (STIM1) to the sub-plasmalemmal region and formation of puncta—structures in which STIM1 interacts and activates calcium channels. ATP depletion induced the formation of STIM1 puncta in PANC1, RAMA37, and HeLa cells. The sequence of events triggered by inhibition of ATP production included a rapid decline of ATP, depletion of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and a slow calcium leak from the ER followed by formation of STIM1 puncta. STIM1 puncta induced by ATP depletion were co-localized with clusters of ORAI1 channels. STIM1–ORAI1 clusters that developed as a result of ATP depletion were very poor mediators of Ca2+ influx. Re-translocation of STIM1 from puncta back to the ER was observed during total ATP depletion. We can therefore conclude that STIM1 translocation and re-translocation as well as formation of STIM1–ORAI1 clusters occur in an ATP-independent fashion and under conditions of PI(4,5)P2 depletion.
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Affiliation(s)
- Michael Chvanov
- Department of Physiology, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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