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Petersen OH. Watching Living Cells in Action in the Exocrine Pancreas: The Palade Prize Lecture. FUNCTION 2022; 4:zqac061. [PMID: 36606242 PMCID: PMC9809903 DOI: 10.1093/function/zqac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
George Palade's pioneering electron microscopical studies of the pancreatic acinar cell revealed the intracellular secretory pathway from the rough endoplasmic reticulum at the base of the cell to the zymogen granules in the apical region. Palade also described for the first time the final stage of exocytotic enzyme secretion into the acinar lumen. The contemporary studies of the mechanism by which secretion is acutely controlled, and how the pancreas is destroyed in the disease acute pancreatitis, rely on monitoring molecular events in the various identified pancreatic cell types in the living pancreas. These studies have been carried out with the help of high-resolution fluorescence recordings, often in conjunction with patch clamp current measurements. In such studies we have gained much detailed information about the regulatory events in the exocrine pancreas in health as well as disease, and new therapeutic opportunities have been revealed.
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Affiliation(s)
- Ole H Petersen
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Wales, CF10 3AX, UK
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2
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Petersen OH. Electrophysiology of Exocrine Gland Cells. Bioelectricity 2022. [DOI: 10.1089/bioe.2022.0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Ole H. Petersen
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
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3
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Petersen OH, Gerasimenko JV, Gerasimenko OV, Gryshchenko O, Peng S. The roles of calcium and ATP in the physiology and pathology of the exocrine pancreas. Physiol Rev 2021; 101:1691-1744. [PMID: 33949875 DOI: 10.1152/physrev.00003.2021] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This review deals with the roles of calcium ions and ATP in the control of the normal functions of the different cell types in the exocrine pancreas as well as the roles of these molecules in the pathophysiology of acute pancreatitis. Repetitive rises in the local cytosolic calcium ion concentration in the apical part of the acinar cells not only activate exocytosis but also, via an increase in the intramitochondrial calcium ion concentration, stimulate the ATP formation that is needed to fuel the energy-requiring secretion process. However, intracellular calcium overload, resulting in a global sustained elevation of the cytosolic calcium ion concentration, has the opposite effect of decreasing mitochondrial ATP production, and this initiates processes that lead to necrosis. In the last few years it has become possible to image calcium signaling events simultaneously in acinar, stellate, and immune cells in intact lobules of the exocrine pancreas. This has disclosed processes by which these cells interact with each other, particularly in relation to the initiation and development of acute pancreatitis. By unraveling the molecular mechanisms underlying this disease, several promising therapeutic intervention sites have been identified. This provides hope that we may soon be able to effectively treat this often fatal disease.
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Affiliation(s)
- Ole H Petersen
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | | | | | - Shuang Peng
- Department of Pathophysiology, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, Guangdong, People's Republic of China
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4
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Petersen OH. Kafka and Asking the Right Question at the Right Time. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab013. [PMID: 35330819 PMCID: PMC8788746 DOI: 10.1093/function/zqab013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Ole H Petersen
- School of Biosciences, Cardiff University, Wales, CF14 0ES, UK,Corresponding author: E-mail:
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5
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Altered Organelle Calcium Transport in Ovarian Physiology and Cancer. Cancers (Basel) 2020; 12:cancers12082232. [PMID: 32785177 PMCID: PMC7464720 DOI: 10.3390/cancers12082232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/14/2022] Open
Abstract
Calcium levels have a huge impact on the physiology of the female reproductive system, in particular, of the ovaries. Cytosolic calcium levels are influenced by regulatory proteins (i.e., ion channels and pumps) localized in the plasmalemma and/or in the endomembranes of membrane-bound organelles. Imbalances between plasma membrane and organelle-based mechanisms for calcium regulation in different ovarian cell subtypes are contributing to ovarian pathologies, including ovarian cancer. In this review, we focused our attention on altered calcium transport and its role as a contributor to tumor progression in ovarian cancer. The most important proteins described as contributing to ovarian cancer progression are inositol trisphosphate receptors, ryanodine receptors, transient receptor potential channels, calcium ATPases, hormone receptors, G-protein-coupled receptors, and/or mitochondrial calcium uniporters. The involvement of mitochondrial and/or endoplasmic reticulum calcium imbalance in the development of resistance to chemotherapeutic drugs in ovarian cancer is also discussed, since Ca2+ channels and/or pumps are nowadays regarded as potential therapeutic targets and are even correlated with prognosis.
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6
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Fast and synchronized fluctuations of cortical actin negatively correlate with nucleoli liquid-liquid phase separation in T cells. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:409-423. [PMID: 32666133 DOI: 10.1007/s00249-020-01446-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 03/10/2020] [Accepted: 07/02/2020] [Indexed: 12/11/2022]
Abstract
Liquid-liquid phase separation is an important mechanism by which eukaryotic cells functionally organize their intracellular content and has been related to cell malignancy and neurodegenerative diseases. These cells also undergo ATP-driven mechanical fluctuations, yet the effect of these fluctuations on the liquid-liquid phase separation remains poorly understood. Here, we employ high-resolution microscopy and atomic force microscopy of live Jurkat T cells to characterize the spectrum of their mechanical fluctuations, and to relate these fluctuations to the extent of nucleoli liquid-liquid phase separation (LLPS). We find distinct fluctuation of the cytoskeleton and of the cell diameter around 110 Hz, which depend on ATP and on myosin activity. Importantly, these fluctuations negatively correlate to nucleoli LLPS. According to a model of cell viscoelasticity, we propose that these fluctuations generate mechanical work that increases intracellular homogeneity by inhibiting LLPS. Thus, active mechanical fluctuations serve as an intracellular regulatory mechanism that could affect multiple pathophysiological conditions.
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7
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Petersen OH, Petersen CC. In Memoriam Sir Michael Berridge 1938 - 2020. Cell Calcium 2020; 88:102209. [PMID: 32353559 DOI: 10.1016/j.ceca.2020.102209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 11/18/2022]
Abstract
The article is an 'In Memoriam' article honouring the memory of Sir Michael Berridge.
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Affiliation(s)
- Ole H Petersen
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK.
| | - Carl Ch Petersen
- Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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8
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Abstract
Veins exhibit spontaneous contractile activity, a phenomenon generally termed vasomotion. This is mediated by spontaneous rhythmical contractions of mural cells (i.e. smooth muscle cells (SMCs) or pericytes) in the wall of the vessel. Vasomotion occurs through interconnected oscillators within and between mural cells, entraining their cycles. Pharmacological studies indicate that a key oscillator underlying vasomotion is the rhythmical calcium ion (Ca2+) release-refill cycle of Ca2+ stores. This occurs through opening of inositol 1,4,5-trisphosphate receptor (IP3R)- and/or ryanodine receptor (RyR)-operated Ca2+ release channels in the sarcoplasmic/endoplasmic (SR/ER) reticulum and refilling by the SR/ER reticulum Ca2+ATPase (SERCA). Released Ca2+ from stores near the plasma membrane diffuse through the cytosol to open Ca2+-activated chloride (Cl-) channels, this generating inward current through an efflux of Cl-. The resultant depolarisation leads to the opening of voltage-dependent Ca2+ channels and possibly increased production of IP3, which through Ca2+-induced Ca2+ release (CICR) of IP3Rs and/or RyRs and IP3R-mediated Ca2+ release provide a means by which store oscillators entrain their activity. Intercellular entrainment normally involves current flow through gap junctions that interconnect mural cells and in many cases this is aided by additional connectivity through the endothelium. Once entrainment has occurred the substantial Ca2+ entry that results from the near-synchronous depolarisations leads to rhythmical contractions of the mural cells, this often leading to vessel constriction. The basis for venous/venular vasomotion has yet to be fully delineated but could improve both venous drainage and capillary/venular absorption of blood plasma-associated fluids.
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9
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Peng S, Gerasimenko JV, Tsugorka T, Gryshchenko O, Samarasinghe S, Petersen OH, Gerasimenko OV. Calcium and adenosine triphosphate control of cellular pathology: asparaginase-induced pancreatitis elicited via protease-activated receptor 2. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0423. [PMID: 27377732 PMCID: PMC4938023 DOI: 10.1098/rstb.2015.0423] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2016] [Indexed: 12/16/2022] Open
Abstract
Exocytotic secretion of digestive enzymes from pancreatic acinar cells is elicited by physiological cytosolic Ca2+ signals, occurring as repetitive short-lasting spikes largely confined to the secretory granule region, that stimulate mitochondrial adenosine triphosphate (ATP) production. By contrast, sustained global cytosolic Ca2+ elevations decrease ATP levels and cause necrosis, leading to the disease acute pancreatitis (AP). Toxic Ca2+ signals can be evoked by products of alcohol and fatty acids as well as bile acids. Here, we have investigated the mechanism by which l-asparaginase evokes AP. Asparaginase is an essential element in the successful treatment of acute lymphoblastic leukaemia, the most common type of cancer affecting children, but AP is a side-effect occurring in about 5–10% of cases. Like other pancreatitis-inducing agents, asparaginase evoked intracellular Ca2+ release followed by Ca2+ entry and also substantially reduced Ca2+ extrusion because of decreased intracellular ATP levels. The toxic Ca2+ signals caused extensive necrosis. The asparaginase-induced pathology depended on protease-activated receptor 2 and its inhibition prevented the toxic Ca2+ signals and necrosis. We tested the effects of inhibiting the Ca2+ release-activated Ca2+ entry by the Ca2+ channel inhibitor GSK-7975A. This markedly reduced asparaginase-induced Ca2+ entry and also protected effectively against the development of necrosis. This article is part of the themed issue ‘Evolution brings Ca2+ and ATP together to control life and death’.
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Affiliation(s)
- Shuang Peng
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK Department of Pathophysiology, Medical College, Jinan University, Guangzhou 510632, People's Republic of China
| | - Julia V Gerasimenko
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK
| | - Tatiana Tsugorka
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK
| | - Oleksiy Gryshchenko
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK Bogomoletz Institute of Physiology, Kiev 01024, Ukraine
| | - Sujith Samarasinghe
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
| | - Ole H Petersen
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XN, Wales, UK
| | - Oleg V Gerasimenko
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK
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10
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Courjaret R, Dib M, Machaca K. Store-Operated Ca 2+ Entry in Oocytes Modulate the Dynamics of IP 3 -Dependent Ca 2+ Release From Oscillatory to Tonic. J Cell Physiol 2016; 232:1095-1103. [PMID: 27504787 DOI: 10.1002/jcp.25513] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/08/2016] [Indexed: 11/10/2022]
Abstract
Ca2+ signaling is ubiquitous and mediates various cellular functions encoded in its spatial, temporal, and amplitude features. Here, we investigate the role of store-operated Ca2+ entry (SOCE) in regulating the temporal dynamics of Ca2+ signals in Xenopus oocytes, which can be either oscillatory or tonic. Oscillatory Ca2+ release from intracellular stores is typically observed at physiological agonist concentration. When Ca2+ release leads to Ca2+ store depletion, this triggers the activation of SOCE that translates into a low-amplitude tonic Ca2+ signal. SOCE has also been implicated in fueling Ca2+ oscillations when activated at low levels. Here, we show that sustained SOCE activation in the presence of IP3 to gate IP3 receptors (IP3 R) results in a pump-leak steady state across the endoplasmic reticulum (ER) membrane that inhibits Ca2+ oscillations and produces a tonic Ca2+ signal. Tonic signaling downstream of SOCE activation relies on focal Ca2+ entry through SOCE ER-plasma membrane (PM) junctions, Ca2+ uptake into the ER, followed by release through open IP3 Rs at distant sites, a process we refer to as "Ca2+ teleporting." Therefore, sustained SOCE activation in the presence of an IP3 -dependent "leak" pathway at the ER membrane results in a switch from oscillatory to tonic Ca2+ signaling. J. Cell. Physiol. 232: 1095-1103, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Raphaël Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Doha, Qatar
| | - Maya Dib
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Doha, Qatar
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Doha, Qatar
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11
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Huang Z, Wang H, Wang J, Zhao M, Sun N, Sun F, Shen J, Zhang H, Xia K, Chen D, Gao M, Hammer RP, Liu Q, Xi Z, Fan X, Wu J. Cannabinoid receptor subtype 2 (CB2R) agonist, GW405833 reduces agonist-induced Ca(2+) oscillations in mouse pancreatic acinar cells. Sci Rep 2016; 6:29757. [PMID: 27432473 PMCID: PMC4949433 DOI: 10.1038/srep29757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/15/2016] [Indexed: 02/05/2023] Open
Abstract
Emerging evidence demonstrates that the blockade of intracellular Ca(2+) signals may protect pancreatic acinar cells against Ca(2+) overload, intracellular protease activation, and necrosis. The activation of cannabinoid receptor subtype 2 (CB2R) prevents acinar cell pathogenesis in animal models of acute pancreatitis. However, whether CB2Rs modulate intracellular Ca(2+) signals in pancreatic acinar cells is largely unknown. We evaluated the roles of CB2R agonist, GW405833 (GW) in agonist-induced Ca(2+) oscillations in pancreatic acinar cells using multiple experimental approaches with acute dissociated pancreatic acinar cells prepared from wild type, CB1R-knockout (KO), and CB2R-KO mice. Immunohistochemical labeling revealed that CB2R protein was expressed in mouse pancreatic acinar cells. Electrophysiological experiments showed that activation of CB2Rs by GW reduced acetylcholine (ACh)-, but not cholecystokinin (CCK)-induced Ca(2+) oscillations in a concentration-dependent manner; this inhibition was prevented by a selective CB2R antagonist, AM630, or was absent in CB2R-KO but not CB1R-KO mice. In addition, GW eliminated L-arginine-induced enhancement of Ca(2+) oscillations, pancreatic amylase, and pulmonary myeloperoxidase. Collectively, we provide novel evidence that activation of CB2Rs eliminates ACh-induced Ca(2+) oscillations and L-arginine-induced enhancement of Ca(2+) signaling in mouse pancreatic acinar cells, which suggests a potential cellular mechanism of CB2R-mediated protection in acute pancreatitis.
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MESH Headings
- Acetylcholine/pharmacology
- Acinar Cells/drug effects
- Acinar Cells/metabolism
- Acinar Cells/physiology
- Animals
- Arginine/pharmacology
- Calcium/metabolism
- Calcium Signaling/drug effects
- Cholinergic Agonists/pharmacology
- Indoles/pharmacology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Morpholines/pharmacology
- Pancreas/cytology
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
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Affiliation(s)
- Zebing Huang
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Haiyan Wang
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Jingke Wang
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Mengqin Zhao
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Nana Sun
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Fangfang Sun
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Jianxin Shen
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Haiying Zhang
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Kunkun Xia
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Dejie Chen
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Ming Gao
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Ronald P. Hammer
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
- Departments of Pharmacology and Psychiatry University of Arizona College of Medicine Tucson, AZ, 85721, USA
| | - Qingrong Liu
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Zhengxiong Xi
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Xuegong Fan
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
| | - Jie Wu
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
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12
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Takeda Y, Shimayoshi T, Holz GG, Noma A. Modeling analysis of inositol 1,4,5-trisphosphate receptor-mediated Ca2+ mobilization under the control of glucagon-like peptide-1 in mouse pancreatic β-cells. Am J Physiol Cell Physiol 2016; 310:C337-47. [PMID: 26741144 PMCID: PMC4888524 DOI: 10.1152/ajpcell.00234.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/19/2015] [Indexed: 01/22/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) is an intestinally derived blood glucose-lowering hormone that potentiates glucose-stimulated insulin secretion from pancreatic β-cells. The secretagogue action of GLP-1 is explained, at least in part, by its ability to stimulate cAMP production so that cAMP may facilitate the release of Ca(2+) from inositol trisphosphate receptor (IP3R)-regulated Ca(2+) stores. However, a quantitative model has yet to be provided that explains the molecular mechanisms and dynamic processes linking GLP-1-stimulated cAMP production to Ca(2+) mobilization. Here, we performed simulation studies to investigate how GLP-1 alters the abilities of Ca(2+) and IP3 to act as coagonists at IP3R Ca(2+) release channels. A new dynamic model was constructed based on the Kaftan model, which demonstrates dual steady-state allosteric regulation of the IP3R by Ca(2+) and IP3. Data obtained from β-cells were then analyzed to understand how GLP-1 facilitates IP3R-mediated Ca(2+) mobilization when UV flash photolysis is used to uncage Ca(2+) and IP3 intracellularly. When the dynamic model for IP3R activation was incorporated into a minimal cell model, the Ca(2+) transients and oscillations induced by GLP-1 were successfully reconstructed. Simulation studies indicated that transient and oscillatory responses to GLP-1 were produced by sequential positive and negative feedback regulation due to fast activation and slow inhibition of the IP3R by Ca(2+). The slow rate of Ca(2+)-dependent inhibition was revealed to provide a remarkable contribution to the time course of the decay of cytosolic Ca(2+) transients. It also served to drive and pace Ca(2+) oscillations that are significant when evaluating how GLP-1 stimulates insulin secretion.
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Affiliation(s)
- Yukari Takeda
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu City, Japan;
| | - Takao Shimayoshi
- Department of Systems Science, Kyoto University, Kyoto, Japan; and
| | - George G Holz
- Departments of Medicine and Pharmacology, SUNY Upstate Medical University, Syracuse, New York
| | - Akinori Noma
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu City, Japan
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13
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Willems PHGM, Pahle J, Stalpers XL, Mugahid D, Nikolaew A, Koopman WJH, Kummer U. PKC-mediated inhibitory feedback of the cholecystokinin 1 receptor controls the shape of oscillatory Ca2+signals. FEBS J 2015; 282:2187-201. [DOI: 10.1111/febs.13267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 01/31/2015] [Accepted: 03/11/2015] [Indexed: 01/10/2023]
Affiliation(s)
- Peter H. G. M. Willems
- Department of Biochemistry; Radboud Institute for Molecular Life Sciences and Centre for Systems Biology and Bioenergetics; Radboud University Medical Center; Nijmegen The Netherlands
| | - Jürgen Pahle
- BIOMS; BioQuant; Heidelberg University; Germany
- School of Computer Science; Manchester Institute of Biotechnology; University of Manchester; UK
| | - Xenia L. Stalpers
- Department of Biochemistry; Radboud Institute for Molecular Life Sciences and Centre for Systems Biology and Bioenergetics; Radboud University Medical Center; Nijmegen The Netherlands
| | - Douaa Mugahid
- Department of Modelling of Biological Processes; COS Heidelberg/BioQuant; Heidelberg University; Germany
| | - Alexander Nikolaew
- Department of Modelling of Biological Processes; COS Heidelberg/BioQuant; Heidelberg University; Germany
| | - Werner J. H. Koopman
- Department of Biochemistry; Radboud Institute for Molecular Life Sciences and Centre for Systems Biology and Bioenergetics; Radboud University Medical Center; Nijmegen The Netherlands
| | - Ursula Kummer
- Department of Modelling of Biological Processes; COS Heidelberg/BioQuant; Heidelberg University; Germany
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14
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Gaspers LD, Bartlett PJ, Politi A, Burnett P, Metzger W, Johnston J, Joseph SK, Höfer T, Thomas AP. Hormone-induced calcium oscillations depend on cross-coupling with inositol 1,4,5-trisphosphate oscillations. Cell Rep 2014; 9:1209-18. [PMID: 25456123 PMCID: PMC6469397 DOI: 10.1016/j.celrep.2014.10.033] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/08/2014] [Accepted: 10/10/2014] [Indexed: 11/29/2022] Open
Abstract
Receptor-mediated oscillations in cytosolic Ca2+ concentration ([Ca2+]i) could originate either directly from an autonomous Ca2+ feedback oscillator at the inositol 1,4,5-trisphosphate (IP3) receptor or as a secondary consequence of IP3 oscillations driven by Ca2+ feedback on IP3 metabolism. It is challenging to discriminate these alternatives, because IP3 fluctuations could drive Ca2+ oscillations or could just be a secondary response to the [Ca2+]i spikes. To investigate this problem, we constructed a recombinant IP3 buffer using type-I IP3 receptor ligand-binding domain fused to GFP (GFP-LBD), which buffers IP3 in the physiological range. This IP3 buffer slows hormone-induced [IP3] dynamics without changing steady-state [IP3]. GFP-LBD perturbed [Ca2+]i oscillations in a dose-dependent manner: it decreased both the rate of [Ca2+]i rise and the speed of Ca2+ wave propagation and, at high levels, abolished [Ca2+]i oscillations completely. These data, together with computational modeling, demonstrate that IP3 dynamics play a fundamental role in generating [Ca2+]i oscillations and waves. Gaspers et al. use a genetically encoded IP3 buffer to suppress IP3 dynamics during hormonal stimulation. Using this approach, they find that positive feedback of Ca2+ on IP3 formation is an essential component, generating long-period, baseline-separated Ca2+ oscillations and intracellular Ca2+ waves.
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Affiliation(s)
- Lawrence D Gaspers
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Paula J Bartlett
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Antonio Politi
- German Cancer Research Center, Division of Theoretical Systems Biology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Paul Burnett
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Walson Metzger
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Jane Johnston
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Suresh K Joseph
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Thomas Höfer
- German Cancer Research Center, Division of Theoretical Systems Biology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Andrew P Thomas
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA.
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15
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Lewarchik CM, Orabi AI, Jin S, Wang D, Muili KA, Shah AU, Eisses JF, Malik A, Bottino R, Jayaraman T, Husain SZ. The ryanodine receptor is expressed in human pancreatic acinar cells and contributes to acinar cell injury. Am J Physiol Gastrointest Liver Physiol 2014; 307:G574-81. [PMID: 25012845 PMCID: PMC4154117 DOI: 10.1152/ajpgi.00143.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Physiological calcium (Ca(2+)) signals within the pancreatic acinar cell regulate enzyme secretion, whereas aberrant Ca(2+) signals are associated with acinar cell injury. We have previously identified the ryanodine receptor (RyR), a Ca(2+) release channel on the endoplasmic reticulum, as a modulator of these pathological signals. In the present study, we establish that the RyR is expressed in human acinar cells and mediates acinar cell injury. We obtained pancreatic tissue from cadaveric donors and identified isoforms of RyR1 and RyR2 by qPCR. Immunofluorescence staining of the pancreas showed that the RyR is localized to the basal region of the acinar cell. Furthermore, the presence of RyR was confirmed from isolated human acinar cells by tritiated ryanodine binding. To determine whether the RyR is functionally active, mouse or human acinar cells were loaded with the high-affinity Ca(2+) dye (Fluo-4 AM) and stimulated with taurolithocholic acid 3-sulfate (TLCS) (500 μM) or carbachol (1 mM). Ryanodine (100 μM) pretreatment reduced the magnitude of the Ca(2+) signal and the area under the curve. To determine the effect of RyR blockade on injury, human acinar cells were stimulated with pathological stimuli, the bile acid TLCS (500 μM) or the muscarinic agonist carbachol (1 mM) in the presence or absence of the RyR inhibitor ryanodine. Ryanodine (100 μM) caused an 81% and 47% reduction in acinar cell injury, respectively, as measured by lactate dehydrogenase leakage (P < 0.05). Taken together, these data establish that the RyR is expressed in human acinar cells and that it modulates acinar Ca(2+) signals and cell injury.
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Affiliation(s)
| | | | | | | | - Kamaldeen A. Muili
- 3Department of Neurological Surgery, Comprehensive Cancer Center, Wexner Medical Center, Ohio State University, Columbus, Ohio;
| | | | | | | | - Rita Bottino
- 4Institute of Cellular Therapeutics, Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - Thottala Jayaraman
- 2Dental Medicine, Children's Hospital of Pittsburgh of UPMC and the University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
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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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17
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Abstract
Intracellular free Ca(2+) ([Ca(2+)]i) is a highly versatile second messenger that regulates a wide range of functions in every type of cell and tissue. To achieve this versatility, the Ca(2+) signaling system operates in a variety of ways to regulate cellular processes that function over a wide dynamic range. This is particularly well exemplified for Ca(2+) signals in the liver, which modulate diverse and specialized functions such as bile secretion, glucose metabolism, cell proliferation, and apoptosis. These Ca(2+) signals are organized to control distinct cellular processes through tight spatial and temporal coordination of [Ca(2+)]i signals, both within and between cells. This article will review the machinery responsible for the formation of Ca(2+) signals in the liver, the types of subcellular, cellular, and intercellular signals that occur, the physiological role of Ca(2+) signaling in the liver, and the role of Ca(2+) signaling in liver disease.
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Affiliation(s)
- Maria Jimena Amaya
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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18
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Abstract
Acute pancreatitis is a human disease in which the pancreatic pro-enzymes, packaged into the zymogen granules of acinar cells, become activated and cause autodigestion. The main causes of pancreatitis are alcohol abuse and biliary disease. A considerable body of evidence indicates that the primary event initiating the disease process is the excessive release of Ca(2+) from intracellular stores, followed by excessive entry of Ca(2+) from the interstitial fluid. However, Ca(2+) release and subsequent entry are also precisely the processes that control the physiological secretion of digestive enzymes in response to stimulation via the vagal nerve or the hormone cholecystokinin. The spatial and temporal Ca(2+) signal patterns in physiology and pathology, as well as the contributions from different organelles in the different situations, are therefore critical issues. There has recently been significant progress in our understanding of both physiological stimulus-secretion coupling and the pathophysiology of acute pancreatitis. Very recently, a promising potential therapeutic development has occurred with the demonstration that the blockade of Ca(2+) release-activated Ca(2+) currents in pancreatic acinar cells offers remarkable protection against Ca(2+) overload, intracellular protease activation and necrosis evoked by a combination of alcohol and fatty acids, which is a major trigger of acute pancreatitis.
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Affiliation(s)
- Julia V Gerasimenko
- MRC Group, School of Biosciences, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK.
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19
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Park S, Lee SI, Shin DM. Role of regulators of g-protein signaling 4 in ca signaling in mouse pancreatic acinar cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:383-8. [PMID: 22359476 PMCID: PMC3282226 DOI: 10.4196/kjpp.2011.15.6.383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 11/08/2011] [Accepted: 11/08/2011] [Indexed: 01/24/2023]
Abstract
Regulators of G-protein signaling (RGS) proteins are regulators of Ca2+ signaling that accelerate the GTPase activity of the G-protein α-subunit. RGS1, RGS2, RGS4, and RGS16 are expressed in the pancreas, and RGS2 regulates G-protein coupled receptor (GPCR)-induced Ca2+ oscillations. However, the role of RGS4 in Ca2+ signaling in pancreatic acinar cells is unknown. In this study, we investigated the mechanism of GPCR-induced Ca2+ signaling in pancreatic acinar cells derived from RGS4-/- mice. RGS4-/- acinar cells showed an enhanced stimulus intensity response to a muscarinic receptor agonist in pancreatic acinar cells. Moreover, deletion of RGS4 increased the frequency of Ca2+ oscillations. RGS4-/- cells also showed increased expression of sarco/endoplasmic reticulum Ca2+ ATPase type 2. However, there were no significant alterations, such as Ca2+ signaling in treated high dose of agonist and its related amylase secretion activity, in acinar cells from RGS4-/- mice. These results indicate that RGS4 protein regulates Ca2+ signaling in mouse pancreatic acinar cells.
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Affiliation(s)
- Soonhong Park
- Department of Oral Biology, Yonsei University College of Dentistry, Seoul 120-752, Korea
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Orabi AI, Shah AU, Muili K, Luo Y, Mahmood SM, Ahmad A, Reed A, Husain SZ. Ethanol enhances carbachol-induced protease activation and accelerates Ca2+ waves in isolated rat pancreatic acini. J Biol Chem 2011; 286:14090-7. [PMID: 21372126 DOI: 10.1074/jbc.m110.196832] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Alcohol abuse is a leading cause of pancreatitis, accounting for 30% of acute cases and 70-90% of chronic cases, yet the mechanisms leading to alcohol-associated pancreatic injury are unclear. An early and critical feature of pancreatitis is the aberrant signaling of Ca(2+) within the pancreatic acinar cell. An important conductor of this Ca(2+) is the basolaterally localized, intracellular Ca(2+) channel ryanodine receptor (RYR). In this study, we examined the effect of ethanol on mediating both pathologic intra-acinar protease activation, a precursor to pancreatitis, as well as RYR Ca(2+) signals. We hypothesized that ethanol sensitizes the acinar cell to protease activation by modulating RYR Ca(2+). Acinar cells were freshly isolated from rat, pretreated with ethanol, and stimulated with the muscarinic agonist carbachol (1 μM). Ethanol caused a doubling in the carbachol-induced activation of the proteases trypsin and chymotrypsin (p < 0.02). The RYR inhibitor dantrolene abrogated the enhancement of trypsin and chymotrypsin activity by ethanol (p < 0.005 for both proteases). Further, ethanol accelerated the speed of the apical to basolateral Ca(2+) wave from 9 to 18 μm/s (p < 0.0005; n = 18-22 cells/group); an increase in Ca(2+) wave speed was also observed with a change from physiologic concentrations of carbachol (1 μM) to a supraphysiologic concentration (1 mM) that leads to protease activation. Dantrolene abrogated the ethanol-induced acceleration of wave speed (p < 0.05; n = 10-16 cells/group). Our results suggest that the enhancement of pathologic protease activation by ethanol is dependent on the RYR and that a novel mechanism for this enhancement may involve RYR-mediated acceleration of Ca(2+) waves.
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Affiliation(s)
- Abrahim I Orabi
- Yale University School of Medicine, New Haven, Connecticut 06520, USA
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21
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Tanimura A. The Development of FRET-Based IP3 Biosensors and Their Use for Monitoring IP3 Dynamics during Ca2+ Oscillations and Ca2+ Waves in Non-Excitable Cells. J Oral Biosci 2011. [DOI: 10.1016/s1349-0079(11)80013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Tanimura A, Morita T, Nezu A, Shitara A, Hashimoto N, Tojyo Y. Use of Fluorescence Resonance Energy Transfer-based Biosensors for the Quantitative Analysis of Inositol 1,4,5-Trisphosphate Dynamics in Calcium Oscillations. J Biol Chem 2009; 284:8910-7. [PMID: 19158094 PMCID: PMC2659248 DOI: 10.1074/jbc.m805865200] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 11/17/2008] [Indexed: 11/06/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) is an intracellular messenger that elicits a wide range of spatial and temporal Ca(2+) signals, and this signaling versatility is exploited to regulate diverse cellular responses. In this study, we have developed a series of IP(3) biosensors that exhibit strong pH stability and varying affinities for IP(3), as well as a method for the quantitative measurement of cytosolic concentrations of IP(3) ([IP(3)](i)) in single living cells. We applied this method to elucidate IP(3) dynamics during agonist-induced Ca(2+) oscillations, and we demonstrated cell type-dependent differences in IP(3) dynamics, a nonfluctuating rise in [IP(3)](i) and repetitive IP(3) spikes during Ca(2+) oscillations in COS-7 cells and HSY-EA1 cells, respectively. The size of the IP(3) spikes in HSY-EA1 cells varied from 10 to 100 nm, and the [IP(3)](i) spike peak was preceded by a Ca(2+) spike peak. These results suggest that repetitive IP(3) spikes in HSY-EA1 cells are passive reflections of Ca(2+) oscillations, and are unlikely to be essential for driving Ca(2+) oscillations. In addition, the interspike periods of Ca(2+) oscillations that occurred during the slow rise in [IP(3)](i) were not shortened by the rise in [IP(3)](i), indicating that IP(3)-dependent and -independent mechanisms may regulate the frequency of Ca(2+) oscillations. The novel method described herein as well as the quantitative information obtained by using this method should provide a valuable and sound basis for future studies on the spatial and temporal regulations of IP(3) and Ca(2+).
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Affiliation(s)
- Akihiko Tanimura
- Departments of Pharmacology and Integrated Human Sciences, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
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24
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Tanimura A, Morita T, Nezu A, Tojyo Y. Monitoring of IP3 dynamics during Ca2+ oscillations in HSY human parotid cell line with FRET-based IP3 biosensors. THE JOURNAL OF MEDICAL INVESTIGATION 2009; 56 Suppl:357-61. [DOI: 10.2152/jmi.56.357] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Akihiko Tanimura
- Department of Pharmacology, School of Dentistry, Health Sciences University of Hokkaido
| | - Takao Morita
- Department of Pharmacology, School of Dentistry, Health Sciences University of Hokkaido
| | - Akihiro Nezu
- Department of Pharmacology, School of Dentistry, Health Sciences University of Hokkaido
| | - Yosuke Tojyo
- Department of Pharmacology, School of Dentistry, Health Sciences University of Hokkaido
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26
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Edwards A, Pallone TL. Mechanisms underlying angiotensin II-induced calcium oscillations. Am J Physiol Renal Physiol 2008; 295:F568-84. [PMID: 18562632 DOI: 10.1152/ajprenal.00107.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To gain insight into the mechanisms that underlie angiotensin II (ANG II)-induced cytoplasmic Ca2+ concentration ([Ca]cyt) oscillations in medullary pericytes, we expanded a prior model of ion fluxes. ANG II stimulation was simulated by doubling maximal inositol trisphosphate (IP3) production and imposing a 90% blockade of K+ channels. We investigated two configurations, one in which ryanodine receptors (RyR) and IP3 receptors (IP3R) occupy a common store and a second in which they reside on separate stores. Our results suggest that Ca2+ release from stores and import from the extracellular space are key determinants of oscillations because both raise [Ca] in subplasmalemmal spaces near RyR. When the Ca2+-induced Ca2+ release (CICR) threshold of RyR is exceeded, the ensuing Ca2+ release is limited by Ca2+ reuptake into stores and export across the plasmalemma. If sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pumps do not remain saturated and sarcoplasmic reticulum Ca2+ stores are replenished, that phase is followed by a resumption of leak from internal stores that leads either to [Ca]cyt elevation below the CICR threshold (no oscillations) or to elevation above it (oscillations). Our model predicts that oscillations are more prone to occur when IP3R and RyR stores are separate because, in that case, Ca2+ released by RyR during CICR can enhance filling of adjacent IP3 stores to favor a high subsequent leak that generates further CICR events. Moreover, the existence or absence of oscillations depends on the set points of several parameters, so that biological variation might well explain the presence or absence of oscillations in individual pericytes.
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Affiliation(s)
- Aurélie Edwards
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA 02155, USA.
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27
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Shah AU, Grant WM, Latif SU, Mannan ZM, Park AJ, Husain SZ. Cyclic AMP accelerates calcium waves in pancreatic acinar cells. Am J Physiol Gastrointest Liver Physiol 2008; 294:G1328-34. [PMID: 18388188 PMCID: PMC3030808 DOI: 10.1152/ajpgi.00440.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytosolic Ca(2+) (Ca(i)(2+)) flux within the pancreatic acinar cell is important both physiologically and pathologically. We examined the role of cAMP in shaping the apical-to-basal Ca(2+) wave generated by the Ca(2+)-activating agonist carbachol. We hypothesized that cAMP modulates intra-acinar Ca(2+) channel opening by affecting either cAMP-dependent protein kinase (PKA) or exchange protein directly activated by cAMP (Epac). Isolated pancreatic acinar cells from rats were stimulated with carbachol (1 muM) with or without vasoactive intestinal polypeptide (VIP) or 8-bromo-cAMP (8-Br-cAMP), and then Ca(i)(2+) was monitored by confocal laser-scanning microscopy. The apical-to-basal carbachol (1 muM)-stimulated Ca(2+) wave was 8.63 +/- 0.68 microm/s; it increased to 19.66 +/- 2.22 microm/s (*P < 0.0005) with VIP (100 nM), and similar increases were observed with 8-Br-cAMP (100 microM). The Ca(2+) rise time after carbachol stimulation was reduced in both regions but to a greater degree in the basal. Lag time and maximal Ca(2+) elevation were not significantly affected by cAMP. The effect of cAMP on Ca(2+) waves also did not appear to depend on extracellular Ca(2+). However, the ryanodine receptor (RyR) inhibitor dantrolene (100 microM) reduced the cAMP-enhancement of wave speed. It was also reduced by the PKA inhibitor PKI (1 microM). 8-(4-chloro-phenylthio)-2'-O-Me-cAMP, a specific agonist of Epac, caused a similar increase as 8-Br-cAMP or VIP. These data suggest that cAMP accelerates the speed of the Ca(2+) wave in pancreatic acinar cells. A likely target of this modulation is the RyR, and these effects are mediated independently by PKA and Epac pathways.
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Affiliation(s)
- Ahsan U. Shah
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | - Wayne M. Grant
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | | | - Zahir M. Mannan
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | - Alexander J. Park
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | - Sohail Z. Husain
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
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28
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Petersen OH. Ca2+ signalling and Ca2+-activated ion channels in exocrine acinar cells. Cell Calcium 2008; 38:171-200. [PMID: 16107275 DOI: 10.1016/j.ceca.2005.06.024] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 01/11/2023]
Abstract
The development of the calcium signalling field, from its early beginnings some 40 years ago to the present, is described. Calcium signalling in exocrine gland acinar cells and the effects of neurotransmitter- or hormone-elicited rises in the cytosolic calcium ion concentration on ion channel gating are reviewed. The highly polarized arrangement of the organelle systems in living acinar cells is described as well as its importance for the physiologically relevant local and polarized calcium signalling events.
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Affiliation(s)
- Ole H Petersen
- MRC Group, The Physiological Laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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29
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Chen XF, Li CX, Wang PY, Li M, Wang WC. Dynamic simulation of the effect of calcium-release activated calcium channel on cytoplasmic Ca2+ oscillation. Biophys Chem 2008; 136:87-95. [PMID: 18538916 DOI: 10.1016/j.bpc.2008.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 04/28/2008] [Accepted: 04/28/2008] [Indexed: 11/26/2022]
Abstract
A mathematical model is proposed to illustrate the activation of STIM1 (stromal interaction molecule 1) protein, the assembly and activation of calcium-release activated calcium (CRAC) channels in T cells. In combination with De Young-Keizer-Li-Rinzel model, we successfully reproduce a sustained Ca(2+) oscillation in cytoplasm. Our results reveal that Ca(2+) oscillation dynamics in cytoplasm can be significantly affected by the way how the Orai1 CRAC channel are assembled and activated. A low sustained Ca(2+) influx is observed through the CRAC channels across the plasma membrane. In particular, our model shows that a tetrameric channel complex can effectively regulate the total quantity of the channels and the ratio of the active channels to the total channels, and a period of Ca(2+) oscillation about 29 s is in agreement with published experimental data. The bifurcation analyses illustrate the different dynamic properties between our mixed Ca(2+) feedback model and the single positive or negative feedback models.
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Affiliation(s)
- Xiao-fang Chen
- Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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30
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Zhang Q, Cao C, Zhang Z, Wier WG, Edwards A, Pallone TL. Membrane current oscillations in descending vasa recta pericytes. Am J Physiol Renal Physiol 2008; 294:F656-66. [PMID: 18184740 DOI: 10.1152/ajprenal.00493.2007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the origin of spontaneous transient inward current (STIC) oscillations in descending vasa recta (DVR) pericytes. In cells clamped at -80 mV, angiotensin II (ANG II; 10 nmol/l) induced oscillations with mean amplitude and frequency of -65.5 pA and 1.2 Hz. Simultaneous recording of cytoplasmic calcium ([Ca(2+)](CYT)) and membrane current oscillations verified their synchrony and the correlation of their amplitudes. Confocal recording in fluo-4-loaded DVR showed that ANG II can induce either stable pericyte [Ca(2+)](CYT) elevation or oscillations, while decreasing adjacent endothelial [Ca(2+)](CYT). Oscillating currents reversed sign at -30.2 mV and were blocked by niflumic acid, implicating charge transfer via Cl(-) ion. Removal of extracellular Ca(2+), blockade of Ca(2+) influx with SKF96365 (30 micromol/l), ryanodine (30 micromol/l), or caffeine (10 mmol/l) inhibited oscillations. In contrast, they were insensitive to removal of extracellular Na(+) and exposure to either nifedipine (1 micromol/l) or 2-aminoethoxydiphenyl borate (10 micromol/l). Ouabain (100 nmol/l) increased basal pericyte [Ca(2+)](CYT) and the frequency of resting STICs but did not affect the larger oscillations that followed ANG II stimulation. We conclude that [Ca(2+)](CYT) oscillations stimulate Cl(-) currents. The former are most likely maintained by repetitive cycles of ryanodine-sensitive SR Ca(2+) release and SKF96365-sensitive store refilling.
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Affiliation(s)
- Qingli Zhang
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Petersen OH, Wakui M, Petersen CC. Intracellular effects of aluminium on receptor-activated cytoplasmic Ca2+ signals in pancreatic acinar cells. CIBA FOUNDATION SYMPOSIUM 2007; 169:237-47; discussion 247-53. [PMID: 1337034 DOI: 10.1002/9780470514306.ch14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The hypothesis that intracellular aluminium may interfere with cytoplasmic Ca2+ signals evoked by the activation of receptors linked to inositol lipid hydrolysis has been tested. Single mouse pancreatic acinar cells were used, because there is much information in this system on the mechanism by which acetylcholine (ACh) evokes cytoplasmic Ca2+ oscillations (spiking) and these spikes can be monitored in internally perfused cells by measuring the Ca(2+)-dependent chloride current. ACh normally evokes repetitive Ca2+ spikes, but when aluminium (1 microM-1 mM) is present in the internal perfusion solution the responses are reduced or absent. When aluminium is acutely infused into the internal perfusion solution the ACh-evoked Ca2+ signals quickly disappear. Aluminium also inhibits Ca2+ signals evoked by the Ca2+ releasing agent caffeine. Preliminary results suggest that silicic acid may protect against the toxic effects of aluminium. Silicic acid and citrate, in the absence of added Al3+, have the effect of enhancing the ACh-evoked Ca2+ signals. This could be due to binding of traces of Al3+ in the solutions. We conclude that aluminium can disrupt receptor-activated cytosolic Ca2+ signals when present inside cells.
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Affiliation(s)
- O H Petersen
- Physiological Laboratory, University of Liverpool, UK
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33
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Kopach O, Kruglikov I, Pivneva T, Voitenko N, Fedirko N. Functional coupling between ryanodine receptors, mitochondria and Ca(2+) ATPases in rat submandibular acinar cells. Cell Calcium 2007; 43:469-81. [PMID: 17889347 DOI: 10.1016/j.ceca.2007.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Revised: 08/01/2007] [Accepted: 08/06/2007] [Indexed: 11/17/2022]
Abstract
Agonist stimulation of exocrine cells leads to the generation of intracellular Ca(2+) signals driven by inositol 1,4,5-trisphosphate receptors (IP(3)Rs) that rapidly become global due to propagation throughout the cell. In many types of excitable cells the intracellular Ca(2+) signal is propagated by a mechanism of Ca(2+)-induced Ca(2+) release (CICR), mediated by ryanodine receptors (RyRs). Expression of RyRs in salivary gland cells has been demonstrated immunocytochemically although their functional role is not clear. We used microfluorimetry to measure Ca(2+) signals in the cytoplasm, in the endoplasmic reticulum (ER) and in mitochondria. In permeabilized acinar cells caffeine induced a dose-dependent, transient decrease of Ca(2+) concentration in the endoplasmic reticulum ([Ca(2+)](ER)). This decrease was inhibited by ryanodine but was insensitive to heparin. Application of caffeine, however, did not elevate cytosolic Ca(2+) concentration ([Ca(2+)](i)) suggesting fast local buffering of Ca(2+) released through RyRs. Indeed, activation of RyRs produced a robust mitochondrial Ca(2+) transient that was prevented by addition of Ca(2+) chelator BAPTA but not EGTA. When mitochondrial Ca(2+) uptake was blocked, activation of RyRs evoked only a non-transient increase in [Ca(2+)](i) and substantially smaller Ca(2+) release from the ER. Upon simultaneous inhibition of mitochondrial Ca(2+) uptake and either plasmalemmal or ER Ca(2+) ATPase, activation of RyRs caused a transient rise in [Ca(2+)](i). Collectively, our data suggest that Ca(2+) released through RyRs is mostly "tunnelled" to mitochondria, while Ca(2+) ATPases are responsible for the fast initial sequestration of Ca(2+). Ca(2+) uptake by mitochondria is critical for maintaining continuous CICR. A complex interplay between RyRs, mitochondria and Ca(2+) ATPases is accomplished through strategic positioning of mitochondria close to both Ca(2+) release sites in the ER and Ca(2+) pumping sites of the plasmalemma and the ER.
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Affiliation(s)
- Olga Kopach
- Department of General Physiology of Nervous System, Bogomoletz Institute of Physiology, Kiev , Ukraine
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34
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Borghans JM, Dupont G, Goldbeter A. Complex intracellular calcium oscillations. A theoretical exploration of possible mechanisms. Biophys Chem 2007; 66:25-41. [PMID: 17029867 DOI: 10.1016/s0301-4622(97)00010-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/1996] [Revised: 01/13/1997] [Accepted: 01/16/1997] [Indexed: 11/16/2022]
Abstract
Intracellular Ca(2+) oscillations are commonly observed in a large number of cell types in response to stimulation by an extracellular agonist. In most cell types the mechanism of regular spiking is well understood and models based on Ca(2+)-induced Ca(2+) release (CICR) can account for many experimental observations. However, cells do not always exhibit simple Ca(2+) oscillations. In response to given agonists, some cells show more complex behaviour in the form of bursting, i.e. trains of Ca(2+) spikes separated by silent phases. Here we develop several theoretical models, based on physiologically plausible assumptions, that could account for complex intracellular Ca(2+) oscillations. The models are all based on one- or two-pool models based on CICR. We extend these models by (i) considering the inhibition of the Ca(2+)-release channel on a unique intracellular store at high cytosolic Ca(2+) concentrations, (ii) taking into account the Ca(2+)-activated degradation of inositol 1,4,5-trisphosphate (IP(3)), or (iii) considering explicity the evolution of the Ca(2+) concentration in two different pools, one sensitive and the other one insensitive to IP(3). Besides simple periodic oscillations, these three models can all account for more complex oscillatory behaviour in the form of bursting. Moreover, the model that takes the kinetics of IP(3) into account shows chaotic behaviour.
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Affiliation(s)
- J M Borghans
- Faculté des Sciences, Université Libre de Bruxelles, Campus Plaine, C.P. 231, B-1050 Brussels, Belgium
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35
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Sarkisov DV, Gelber SE, Walker JW, Wang SSH. Synapse specificity of calcium release probed by chemical two-photon uncaging of inositol 1,4,5-trisphosphate. J Biol Chem 2007; 282:25517-26. [PMID: 17540776 DOI: 10.1074/jbc.m609672200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biological messengers can be "caged" by adding a single photosensitive group that can be photolyzed by a light flash to achieve spatially and temporally precise biochemical control. Here we report that photolysis of a double-caged form of the second messenger inositol 1,4,5-trisphosphate (IP3) triggers focal calcium release in Purkinje cell somata, dendrites, and spines as measured by two-photon microscopy. In calbindin knock-out Purkinje cells, peak calcium increased with flash energy with higher cooperativity for double-caged IP3 than for conventional single-caged IP3, consistent with a chemical two-photon effect. Spine photolysis of double-caged IP3 led to local calcium release. Uncaging of glycerophosphoryl-myo-inositol 4,5-bisphosphate (gPIP2), a poorly metabolizable IP3 analog, led to less well localized release. Thus, IP3 breakdown is necessary for spine-specificity. IP3- and gPIP2-evoked signals declined from peak with similar, slow time courses, indicating that release lasts hundreds of milliseconds and is terminated not by IP3 degradation but by intrinsic receptor dynamics. Based on measurements of spine-dendrite coupling, IP3-evoked calcium signals are expected to be at least 2.4-fold larger in their spine of origin than in nearby spines, allowing IP3 to act as a synapse-specific second messenger. Unexpectedly, single-caged IP3 led to less release in somata and was ineffective in dendrites and spines. Calcium release using caged gPIP2 was inhibited by the addition of single-caged IP3, suggesting that single-caged IP3 is an antagonist of calcium release. Caging at multiple sites may be an effective general approach to reducing residual receptor interaction.
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Affiliation(s)
- Dmitry V Sarkisov
- Department of Physics and Molecular Biology and Program in Neuroscience, Princeton University, Princeton, New Jersey 08544, USA
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36
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McCarron JG, Chalmers S, Bradley KN, MacMillan D, Muir TC. Ca2+ microdomains in smooth muscle. Cell Calcium 2006; 40:461-93. [PMID: 17069885 DOI: 10.1016/j.ceca.2006.08.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 08/23/2006] [Indexed: 02/03/2023]
Abstract
In smooth muscle, Ca(2+) controls diverse activities including cell division, contraction and cell death. Of particular significance in enabling Ca(2+) to perform these multiple functions is the cell's ability to localize Ca(2+) signals to certain regions by creating high local concentrations of Ca(2+) (microdomains), which differ from the cytoplasmic average. Microdomains arise from Ca(2+) influx across the plasma membrane or release from the sarcoplasmic reticulum (SR) Ca(2+) store. A single Ca(2+) channel can create a microdomain of several micromolar near (approximately 200 nm) the channel. This concentration declines quickly with peak rates of several thousand micromolar per second when influx ends. The high [Ca(2+)] and the rapid rates of decline target Ca(2+) signals to effectors in the microdomain with rapid kinetics and enable the selective activation of cellular processes. Several elements within the cell combine to enable microdomains to develop. These include the brief open time of ion channels, localization of Ca(2+) by buffering, the clustering of ion channels to certain regions of the cell and the presence of membrane barriers, which restrict the free diffusion of Ca(2+). In this review, the generation of microdomains arising from Ca(2+) influx across the plasma membrane and the release of the ion from the SR Ca(2+) store will be discussed and the contribution of mitochondria and the Golgi apparatus as well as endogenous modulators (e.g. cADPR and channel binding proteins) will be considered.
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Affiliation(s)
- John G McCarron
- Department of Physiology and Pharmacology, University of Strathclyde, SIPBS, Glasgow, UK.
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37
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Yamashita M. ‘Quantal’ Ca2+release reassessed - a clue to oscillation and synchronization. FEBS Lett 2006; 580:4979-83. [PMID: 16938295 DOI: 10.1016/j.febslet.2006.08.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 08/14/2006] [Indexed: 11/26/2022]
Abstract
Ca(2+) release from intracellular Ca(2+) stores, a pivotal event in Ca(2+) signaling, is a 'quantal' process; it terminates after a rapid release of a fraction of stored Ca(2+). To explain the 'quantal' nature, 'all-or-none' model and 'steady-state' model were proposed. This article shortly reviews these hypotheses and considers a recently proposed mechanism, 'luminal potential' model, in which the membrane potential of Ca(2+) store regulates Ca(2+) efflux. By reassessing the 'quantal' nature, other important features of Ca(2+) signaling, oscillation and synchronization, are highlighted. The mechanism for 'quantal' Ca(2+) release may underlie the temporal and spatial control of Ca(2+) signaling.
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Affiliation(s)
- Masayuki Yamashita
- Department of Physiology I, Nara Medical University, Shijo-cho 840, Kashihara 634-8521, Japan.
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38
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Matsu-ura T, Michikawa T, Inoue T, Miyawaki A, Yoshida M, Mikoshiba K. Cytosolic inositol 1,4,5-trisphosphate dynamics during intracellular calcium oscillations in living cells. ACTA ACUST UNITED AC 2006; 173:755-65. [PMID: 16754959 PMCID: PMC2063891 DOI: 10.1083/jcb.200512141] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We developed genetically encoded fluorescent inositol 1,4,5-trisphosphate (IP3) sensors that do not severely interfere with intracellular Ca2+ dynamics and used them to monitor the spatiotemporal dynamics of both cytosolic IP3 and Ca2+ in single HeLa cells after stimulation of exogenously expressed metabotropic glutamate receptor 5a or endogenous histamine receptors. IP3 started to increase at a relatively constant rate before the pacemaker Ca2+ rise, and the subsequent abrupt Ca2+ rise was not accompanied by any acceleration in the rate of increase in IP3. Cytosolic [IP3] did not return to its basal level during the intervals between Ca2+ spikes, and IP3 gradually accumulated in the cytosol with a little or no fluctuations during cytosolic Ca2+ oscillations. These results indicate that the Ca2+-induced regenerative IP3 production is not a driving force of the upstroke of Ca2+ spikes and that the apparent IP3 sensitivity for Ca2+ spike generation progressively decreases during Ca2+ oscillations.
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MESH Headings
- Calcium/metabolism
- Calcium Channels/metabolism
- Calcium Signaling/physiology
- Cell Membrane/metabolism
- Cytosol/metabolism
- HeLa Cells
- Humans
- In Vitro Techniques
- Inositol 1,4,5-Trisphosphate/biosynthesis
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors
- Protein Binding
- Receptor, Metabotropic Glutamate 5
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Histamine/metabolism
- Receptors, Metabotropic Glutamate/genetics
- Receptors, Metabotropic Glutamate/metabolism
- Time Factors
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Affiliation(s)
- Toru Matsu-ura
- Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, Saitama 351-0198, Japan
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39
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Politi A, Gaspers LD, Thomas AP, Höfer T. Models of IP3 and Ca2+ oscillations: frequency encoding and identification of underlying feedbacks. Biophys J 2006; 90:3120-33. [PMID: 16500959 PMCID: PMC1432125 DOI: 10.1529/biophysj.105.072249] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 01/25/2006] [Indexed: 11/18/2022] Open
Abstract
Hormones that act through the calcium-releasing messenger, inositol 1,4,5-trisphosphate (IP3), cause intracellular calcium oscillations, which have been ascribed to calcium feedbacks on the IP3 receptor. Recent studies have shown that IP3 levels oscillate together with the cytoplasmic calcium concentration. To investigate the functional significance of this phenomenon, we have developed mathematical models of the interaction of both second messengers. The models account for both positive and negative feedbacks of calcium on IP3 metabolism, mediated by calcium activation of phospholipase C and IP3 3-kinase, respectively. The coupled IP3 and calcium oscillations have a greatly expanded frequency range compared to calcium fluctuations obtained with clamped IP3. Therefore the feedbacks can be physiologically important in supporting the efficient frequency encoding of hormone concentration observed in many cell types. This action of the feedbacks depends on the turnover rate of IP3. To shape the oscillations, positive feedback requires fast IP3 turnover, whereas negative feedback requires slow IP3 turnover. The ectopic expression of an IP3 binding protein has been used to decrease the rate of IP3 turnover experimentally, resulting in a dose-dependent slowing and eventual quenching of the Ca2+ oscillations. These results are consistent with a model based on positive feedback of Ca2+ on IP3 production.
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Affiliation(s)
- Antonio Politi
- Department of Theoretical Biophysics, Institute of Biology, Humboldt University Berlin, 10115 Berlin, Germany
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40
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Sneyd J, Tsaneva-Atanasova K, Reznikov V, Bai Y, Sanderson MJ, Yule DI. A method for determining the dependence of calcium oscillations on inositol trisphosphate oscillations. Proc Natl Acad Sci U S A 2006; 103:1675-80. [PMID: 16446452 PMCID: PMC1413622 DOI: 10.1073/pnas.0506135103] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In some cell types, oscillations in the concentration of free intracellular calcium ([Ca2+]) are accompanied by oscillations in the concentration of inositol 1,4,5-trisphosphate ([IP3]). However, in most cell types it is still an open question as to whether oscillations in [IP3] are necessary for Ca2+ oscillations in vivo, or whether they merely follow passively. Using a wide range of models, we show that the response to an artificially applied pulse of IP3 can be used to distinguish between these two cases. Hence, we show that muscarinic receptor-mediated, long-period Ca2+ oscillations in pancreatic acinar cells depend on [IP3] oscillations, whereas short-period Ca2+ oscillations in airway smooth muscle do not.
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Affiliation(s)
- J Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand.
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41
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MacMillan D, Chalmers S, Muir TC, McCarron JG. IP3-mediated Ca2+ increases do not involve the ryanodine receptor, but ryanodine receptor antagonists reduce IP3-mediated Ca2+ increases in guinea-pig colonic smooth muscle cells. J Physiol 2005; 569:533-44. [PMID: 16195318 PMCID: PMC1464235 DOI: 10.1113/jphysiol.2005.096529] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Smooth muscle responds to IP3-generating (sarcolemma acting) neurotransmitters and hormones by releasing Ca2+ from the sarcoplasmic reticulum (SR) via IP3 receptors (IP3Rs). This release may propagate as Ca2+ waves. The Ca2+ signal emanating from IP3 generation may be amplified by its activating further Ca2+ release from ryanodine receptors (RyRs) in the process of Ca2+-induced Ca2+ release (CICR). Evidence for this proposal has relied largely on the use of blocking drugs such as ryanodine, tetracaine and dantrolene, reportedly specific inhibitors of RyRs. Here we have examined whether or not Ca2+ released via IP3Rs subsequently activates RyRs. In addition, the specificity of the blocking agents has been assessed by determining the extent of their ability to block IP3-mediated Ca2+ release under conditions in which RyRs were not activated. IP3-evoked Ca2+ release and Ca2+ waves did not require or activate RyRs. However, the RyR blocking drugs inhibited IP3-mediated Ca2+ signals at concentrations thought to be selective for RyRs. In single colonic smooth muscle cells, voltage clamped in the whole cell configuration, carbachol (CCh) evoked propagating Ca2+ waves which were not inhibited by ryanodine when the sarcolemma potential was -70 mV. At -20 mV, at which potential the SR Ca2+ content was increased and RyRs activated, ryanodine inhibited the Ca2+ waves. Photolysed caged IP3 increased [Ca2+]c; ryanodine, by itself, did not reduce the IP3-evoked [Ca2+]c increase when the sarcolemma potential was maintained at -70 mV. However, after activation of RyRs by caffeine, in the continued presence of ryanodine, the IP3-evoked [Ca2+]c increase was inhibited. In other experiments, RyRs were activated (as evidenced by the occurrence of spontaneous transient outward currents) by depolarizing the sarcolemma to -20 mV and again ryanodine was effective in inhibiting IP3-evoked Ca2+ increase. Thus while ineffective by itself, ryanodine inhibited IP3-evoked Ca2+ increases, presumably by causing persistent opening of the channel and depleting the SR of Ca2+, after RyRs were activated. These experiments establish that IP3-evoked Ca2+ release and Ca2+ waves do not activate RyRs; had they done so ryanodine would have inhibited the Ca2+ increase. However, under conditions where ryanodine was ineffective against the IP3-evoked Ca2+ transient (i.e. when RyRs were not activated, e.g. at a membrane potential of -70 mV) tetracaine and dantrolene each blocked IP3-evoked Ca2+ increases. The results show that although IP3-mediated Ca2+ release does not activate RyRs, RyR blockers can inhibit IP3-mediated Ca2+ signals.
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Affiliation(s)
- Debbi MacMillan
- Institute of Biomedical and Life Sciences, Neuroscience and Biomedical Systems, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
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42
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Lin X, Várnai P, Csordás G, Balla A, Nagai T, Miyawaki A, Balla T, Hajnóczky G. Control of Calcium Signal Propagation to the Mitochondria by Inositol 1,4,5-Trisphosphate-binding Proteins. J Biol Chem 2005; 280:12820-32. [PMID: 15644334 DOI: 10.1074/jbc.m411591200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytosolic Ca2+ ([Ca2+]c) signals triggered by many agonists are established through the inositol 1,4,5-trisphosphate (IP3) messenger pathway. This pathway is believed to use Ca2+-dependent local interactions among IP3 receptors (IP3R) and other Ca2+ channels leading to coordinated Ca2+ release from the endoplasmic reticulum throughout the cell and coupling Ca2+ entry and mitochondrial Ca2+ uptake to Ca2+ release. To evaluate the role of IP3 in the local control mechanisms that support the propagation of [Ca2+]c waves, store-operated Ca2+ entry, and mitochondrial Ca2+ uptake, we used two IP3-binding proteins (IP3BP): 1) the PH domain of the phospholipase C-like protein, p130 (p130PH); and 2) the ligand-binding domain of the human type-I IP3R (IP3R224-605). As expected, p130PH-GFP and GFP-IP3R224-605 behave as effective mobile cytosolic IP3 buffers. In COS-7 cells, the expression of IP3BPs had no effect on store-operated Ca2+ entry. However, the IP3-linked [Ca2+]c signal appeared as a regenerative wave and IP3BPs slowed down the wave propagation. Most importantly, IP3BPs largely inhibited the mitochondrial [Ca2+] signal and decreased the relationship between the [Ca2+]c and mitochondrial [Ca2+] signals, indicating disconnection of the mitochondria from the [Ca2+]c signal. These data suggest that IP3 elevations are important to regulate the local interactions among IP3Rs during propagation of [Ca2+]c waves and that the IP3-dependent synchronization of Ca2+ release events is crucial for the coupling between Ca2+ release and mitochondrial Ca2+ uptake.
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Affiliation(s)
- Xuena Lin
- Department of Pathology, Anatomy & Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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43
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Yano K, Petersen OH, Tepikin AV. Dual sensitivity of sarcoplasmic/endoplasmic Ca2+-ATPase to cytosolic and endoplasmic reticulum Ca2+ as a mechanism of modulating cytosolic Ca2+ oscillations. Biochem J 2005; 383:353-60. [PMID: 15260801 PMCID: PMC1134077 DOI: 10.1042/bj20040629] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of ER (endoplasmic reticulum) Ca2+ on cytosolic Ca2+ oscillations in pancreatic acinar cells were investigated using mathematical models of the Ca2+ oscillations. We first examined the mathematical model of SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) to reproduce the highly co-operative inhibitory effect of Ca2+ in the ER lumen on ER Ca2+ uptake in the acinar cells. The model predicts that luminal Ca2+ would most probably inhibit the conversion of the conformation state with luminal Ca2+-binding sites (E2) into the conformation state with cytoplasmic Ca2+-binding sites (E1). The SERCA model derived from this prediction showed dose-response relationships to cytosolic and luminal Ca2+ concentrations that were consistent with the experimental data from the acinar cells. According to a mathematical model of cytosolic Ca2+ oscillations based on the modified SERCA model, a small decrease in the concentration of endoplasmic reticulum Ca2+ (approx. 20% of the total) was sufficient to abolish the oscillations. When a single type of IP3R (IP3 receptor) was included in the model, store depletion decreased the spike frequency. However, the frequency became less sensitive to store depletion when we added another type of IP3R with higher sensitivity to the concentration of free Ca2+ in the cytosol. Bifurcation analysis of the mathematical model showed that the loss of Ca2+ from the ER lumen decreased the sensitivity of cytosolic Ca2+ oscillations to IP3 [Ins(1,4,5)P3]. The addition of a high-affinity IP3R did not alter this property, but significantly decreased the sensitivity of the spike frequency to IP3. Our mathematical model demonstrates how luminal Ca2+, through its effect on Ca2+ uptake, can control cytosolic Ca2+ oscillations.
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Affiliation(s)
- Kojiro Yano
- The Physiological Laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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44
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Turvey MR, Fogarty KE, Thorn P. Inositol (1,4,5)-trisphosphate receptor links to filamentous actin are important for generating local Ca2+ signals in pancreatic acinar cells. J Cell Sci 2005; 118:971-80. [PMID: 15713744 DOI: 10.1242/jcs.01693] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We explored a potential structural and functional link between filamentous actin (F-actin) and inositol (1,4,5)-trisphosphate receptors (IP3Rs) in mouse pancreatic acinar cells. Using immunocytochemistry, F-actin and type 2 and 3 IP3Rs (IP3R2 and IP3R3) were identified in a cellular compartment immediately beneath the apical plasma membrane. In an effort to demonstrate that IP3R distribution is dependent on an intact F-actin network in the apical subplasmalemmal region, cells were treated with the actin-depolymerising agent latrunculin B. Immunocytochemistry indicated that latrunculin B treatment reduced F-actin in the basolateral subplasmalemmal compartment, and reduced and fractured F-actin in the apical subplasmalemmal compartment. This latrunculin-B-induced loss of F-actin in the apical region coincided with a reduction in IP3R2 and IP3R3, with the remaining IP3Rs localized with the remaining F-actin. Experiments using western blot analysis showed that IP3R3s are resistant to extraction by detergents, which indicates a potential interaction with the cytoskeleton. Latrunculin B treatment in whole-cell patch-clamped cells inhibited Ca2+-dependent Cl– current spikes evoked by inositol (2,4,5)-trisphosphate; this is due to an inhibition of the underlying local Ca2+ signal. Based on these findings, we suggest that IP3Rs form links with F-actin in the apical domain and that these links are essential for the generation of local Ca2+ spikes.
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Affiliation(s)
- Matthew R Turvey
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 IPD, UK
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45
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Verkhratsky A. Physiology and Pathophysiology of the Calcium Store in the Endoplasmic Reticulum of Neurons. Physiol Rev 2005; 85:201-79. [PMID: 15618481 DOI: 10.1152/physrev.00004.2004] [Citation(s) in RCA: 560] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum (ER) is the largest single intracellular organelle, which is present in all types of nerve cells. The ER is an interconnected, internally continuous system of tubules and cisterns, which extends from the nuclear envelope to axons and presynaptic terminals, as well as to dendrites and dendritic spines. Ca2+release channels and Ca2+pumps residing in the ER membrane provide for its excitability. Regulated ER Ca2+release controls many neuronal functions, from plasmalemmal excitability to synaptic plasticity. Enzymatic cascades dependent on the Ca2+concentration in the ER lumen integrate rapid Ca2+signaling with long-lasting adaptive responses through modifications in protein synthesis and processing. Disruptions of ER Ca2+homeostasis are critically involved in various forms of neuropathology.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester, Faculty of Biological Sciences, United Kingdom.
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46
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Wang X, Huang G, Luo X, Penninger JM, Muallem S. Role of Regulator of G Protein Signaling 2 (RGS2) in Ca2+ Oscillations and Adaptation of Ca2+ Signaling to Reduce Excitability of RGS2–/– Cells. J Biol Chem 2004; 279:41642-9. [PMID: 15292238 DOI: 10.1074/jbc.m406450200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins accelerate the GTPase activity of Galpha subunits to determine the duration of the stimulated state and control G protein-coupled receptor-mediated cell signaling. RGS2 is an RGS protein that shows preference toward Galpha(q). To better understand the role of RGS2 in Ca(2+) signaling and Ca(2+) oscillations, we characterized Ca(2+) signaling in cells derived from RGS2(-/-) mice. Deletion of RGS2 modified the kinetic of inositol 1,4,5-trisphosphate (IP(3)) production without affecting the peak level of IP(3), but rather increased the steady-state level of IP(3) at all agonist concentrations. The increased steady-state level of IP(3) led to an increased frequency of [Ca(2+)](i) oscillations. The cells were adapted to deletion of RGS2 by reducing Ca(2+) signaling excitability. Reduced excitability was achieved by adaptation of all transporters to reduce Ca(2+) influx into the cytosol. Thus, IP(3) receptor 1 was down-regulated and IP(3) receptor 3 was up-regulated in RGS2(-/-) cells to reduce the sensitivity for IP(3) to release Ca(2+) from the endoplasmic reticulum to the cytosol. Sarco/endoplasmic reticulum Ca(2+) ATPase 2b was up-regulated to more rapidly remove Ca(2+) from the cytosol of RGS2(-/-) cells. Agonist-stimulated Ca(2+) influx was reduced, and Ca(2+) efflux by plasma membrane Ca(2+) was up-regulated in RGS2(-/-) cells. The result of these adaptive mechanisms was the reduced excitability of Ca(2+) signaling, as reflected by the markedly reduced response of RGS2(-/-) cells to changes in the endoplasmic reticulum Ca(2+) load and to an increase in extracellular Ca(2+). These findings highlight the central role of RGS proteins in [Ca(2+)](i) oscillations and reveal a prominent plasticity and adaptability of the Ca(2+) signaling apparatus.
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Affiliation(s)
- Xinhua Wang
- Department of Physiology University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9040, USA
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47
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McCarron JG, Bradley KN, MacMillan D, Chalmers S, Muir TC. The sarcoplasmic reticulum, Ca2+ trapping, and wave mechanisms in smooth muscle. Physiology (Bethesda) 2004; 19:138-47. [PMID: 15143210 DOI: 10.1152/nips.01518.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sarcoplasmic reticulum (SR) and apposed regions of the sarcolemma passively trap Ca2+ entering the cell to limit the rise in cytoplasmic Ca2+ concentration without SR pump involvement. When "leaky," the SR facilitates Ca2+ entry to the cytoplasm. SR Ca2+ release via inositol 1,4,5-trisphosphate receptors (IP(3)Rs) propagates as calcium waves; IP(3)Rs alone account for wave propagation.
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Affiliation(s)
- John G McCarron
- Institute of Biomedical and Life Sciences, Neuroscience and Biomedical Systems, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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48
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Koenigsberger M, Sauser R, Lamboley M, Bény JL, Meister JJ. Ca2+ dynamics in a population of smooth muscle cells: modeling the recruitment and synchronization. Biophys J 2004; 87:92-104. [PMID: 15240448 PMCID: PMC1304399 DOI: 10.1529/biophysj.103.037853] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Accepted: 03/16/2004] [Indexed: 11/18/2022] Open
Abstract
Many experimental studies have shown that arterial smooth muscle cells respond with cytosolic calcium rises to vasoconstrictor stimulation. A low vasoconstrictor concentration gives rise to asynchronous spikes in the calcium concentration in a few cells (asynchronous flashing). With a greater vasoconstrictor concentration, the number of smooth muscle cells responding in this way increases (recruitment) and calcium oscillations may appear. These oscillations may eventually synchronize and generate arterial contraction and vasomotion. We show that these phenomena of recruitment and synchronization naturally emerge from a model of a population of smooth muscle cells coupled through their gap junctions. The effects of electrical, calcium, and inositol 1,4,5-trisphosphate coupling are studied. A weak calcium coupling is crucial to obtain a synchronization of calcium oscillations and the minimal required calcium permeability is deduced. Moreover, we note that an electrical coupling can generate oscillations, but also has a desynchronizing effect. Inositol 1,4,5-trisphosphate diffusion does not play an important role to achieve synchronization. Our model is validated by published in vitro experiments obtained on rat mesenteric arterial segments.
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Affiliation(s)
- Michèle Koenigsberger
- Laboratory of Cell Biophysics, Swiss Federal Institute of Technology, Lausanne, Switzerland.
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49
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McCarron JG, MacMillan D, Bradley KN, Chalmers S, Muir TC. Origin and Mechanisms of Ca2+ Waves in Smooth Muscle as Revealed by Localized Photolysis of Caged Inositol 1,4,5-Trisphosphate. J Biol Chem 2004; 279:8417-27. [PMID: 14660609 DOI: 10.1074/jbc.m311797200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cytosolic Ca(2+) concentration ([Ca(2+)](c)) controls diverse cellular events via various Ca(2+) signaling patterns; the latter are influenced by the method of cell activation. Here, in single-voltage clamped smooth muscle cells, sarcolemma depolarization generated uniform increases in [Ca(2+)](c) throughout the cell entirely by Ca(2+) influx. On the other hand, the Ca(2+) signal produced by InsP(3)-generating agonists was a propagated wave. Using localized uncaged InsP(3), the forward movement of the Ca(2+) wave arose from Ca(2+)-induced Ca(2+) release at the InsP(3) receptor (InsP(3)R) without ryanodine receptor involvement. The decline in [Ca(2+)](c) (the back of the wave) occurred from a functional compartmentalization of the store, which rendered the site of InsP(3)-mediated Ca(2+) release, and only this site, refractory to the phosphoinositide. The functional compartmentalization arose by a localized feedback deactivation of InsP(3) receptors produced by an increased [Ca(2+)](c) rather than a reduced luminal [Ca(2+)] or an increased cytoplasmic [InsP(3)]. The deactivation of the InsP(3) receptor was delayed in onset, compared with the time of the rise in [Ca(2+)](c), persisted (>30 s) even when [Ca(2+)](c) had regained resting levels, and was not prevented by kinase or phosphatase inhibitors. Thus different forms of cell activation generate distinct Ca(2+) signaling patterns in smooth muscle. Sarcolemma Ca(2+) entry increases [Ca(2+)](c) uniformly; agonists activate InsP(3)R and produce Ca(2+) waves. Waves progress by Ca(2+)-induced Ca(2+) release at InsP(3)R, and persistent Ca(2+)-dependent inhibition of InsP(3)R accounts for the decline in [Ca(2+)](c) at the back of the wave.
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MESH Headings
- Animals
- Caffeine/pharmacology
- Calcium/analysis
- Calcium/metabolism
- Calcium/pharmacology
- Calcium Channels/drug effects
- Calcium Channels/physiology
- Carbachol/pharmacology
- Cell Membrane/metabolism
- Colon
- Electric Conductivity
- Enzyme Activation
- Feedback, Physiological
- Guinea Pigs
- Inositol 1,4,5-Trisphosphate/chemistry
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors
- Kinetics
- Male
- Muscle, Smooth/metabolism
- Photolysis
- Protein Kinase C/metabolism
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/physiology
- Ryanodine Receptor Calcium Release Channel/physiology
- Sarcolemma/metabolism
- Signal Transduction
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Affiliation(s)
- John G McCarron
- Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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50
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Harks EGA, Scheenen WJJM, Peters PHJ, van Zoelen EJJ, Theuvenet APR. Prostaglandin F2 alpha induces unsynchronized intracellular calcium oscillations in monolayers of gap junctionally coupled NRK fibroblasts. Pflugers Arch 2003; 447:78-86. [PMID: 12851822 DOI: 10.1007/s00424-003-1126-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Accepted: 05/28/2003] [Indexed: 11/26/2022]
Abstract
We investigated the intracellular calcium oscillations induced by prostaglandin F2alpha (PGF2alpha) in individual cells of confluent, gap junction-coupled monolayers of normal rat kidney (NRK) fibroblasts. PGF2alpha (1000 nM) induced oscillations in more than 90% of the cells in the monolayer, but the frequency of these oscillations was highly variable between individual cells (0.2-1.4 min(-1)). The initial calcium peak resulted from calcium release from IP3-sensitive stores, while subsequent calcium transients were mediated by interplay between both IP3-sensitive calcium stores and calcium influx. The oscillation frequency was increased by sensitizing the IP3 receptor with thimerosal (10 microM) and depended on the extracellular calcium concentration. Thapsigargin (5 nM), which inhibits reuptake of calcium into the stores, only seemed to reduce the amplitude of the oscillation. Patch-clamp experiments revealed that PGF2alpha did not inhibit electrical coupling of the NRK cells in the monolayer. Gap junctional permeability of NRK cells thus appears to be sufficient to allow electrical coupling, resulting in a uniform membrane potential throughout the entire monolayer, but insufficient to synchronize the intracellular calcium oscillations upon PGF2alpha stimulation.
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Affiliation(s)
- Erik G A Harks
- Department of Cell Biology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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