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Manhas N, Sneyd J, Pardasani KR. Modelling the transition from simple to complex Ca²⁺ oscillations in pancreatic acinar cells. J Biosci 2014; 39:463-84. [PMID: 24845510 DOI: 10.1007/s12038-014-9430-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A mathematical model is proposed which systematically investigates complex calcium oscillations in pancreatic acinar cells. This model is based on calcium-induced calcium release via inositol trisphosphate receptors (IPR) and ryanodine receptors (RyR) and includes calcium modulation of inositol (1,4,5) trisphosphate (IP3) levels through feedback regulation of degradation and production. In our model, the apical and the basal regions are separated by a region containing mitochondria, which is capable of restricting Ca2+ responses to the apical region. We were able to reproduce the observed oscillatory patterns, from baseline spikes to sinusoidal oscillations. The model predicts that calcium-dependent production and degradation of IP3 is a key mechanism for complex calcium oscillations in pancreatic acinar cells. A partial bifurcation analysis is performed which explores the dynamic behaviour of the model in both apical and basal regions.
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Affiliation(s)
- Neeraj Manhas
- Department of Mathematics, Maulana Azad National Institute of Technology, Bhopal 462 051, India,
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Gerasimenko J, Ferdek P, Fischer L, Gukovskaya AS, Pandol SJ. Inhibitors of Bcl-2 protein family deplete ER Ca2+ stores in pancreatic acinar cells. Pflugers Arch 2010; 460:891-900. [PMID: 20617337 PMCID: PMC2937140 DOI: 10.1007/s00424-010-0859-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 06/11/2010] [Accepted: 06/17/2010] [Indexed: 11/30/2022]
Abstract
Physiological stimulation of pancreatic acinar cells by cholecystokinin and acetylcholine activate a spatial-temporal pattern of cytosolic [Ca+2] changes that are regulated by a coordinated response of inositol 1,4,5-trisphosphate receptors (IP3Rs), ryanodine receptors (RyRs) and calcium-induced calcium release (CICR). For the present study, we designed experiments to determine the potential role of Bcl-2 proteins in these patterns of cytosolic [Ca+2] responses. We used small molecule inhibitors that disrupt the interactions between prosurvival Bcl-2 proteins (i.e. Bcl-2 and Bcl-xl) and proapoptotic Bcl-2 proteins (i.e. Bax) and fluorescence microfluorimetry techniques to measure both cytosolic [Ca+2] and endoplasmic reticulum [Ca+2]. We found that the inhibitors of Bcl-2 protein interactions caused a slow and complete release of intracellular agonist-sensitive stores of calcium. The release was attenuated by inhibitors of IP3Rs and RyRs and substantially reduced by strong [Ca2+] buffering. Inhibition of IP3Rs and RyRs also dramatically reduced activation of apoptosis by BH3I-2′. CICR induced by different doses of BH3I-2′ in Bcl-2 overexpressing cells was markedly decreased compared with control. The results suggest that Bcl-2 proteins regulate calcium release from the intracellular stores and suggest that the spatial-temporal patterns of agonist-stimulated cytosolic [Ca+2] changes are regulated by differential cellular distribution of interacting pairs of prosurvival and proapoptotic Bcl-2 proteins.
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Affiliation(s)
- Julia Gerasimenko
- The Physiological Laboratory, University of Liverpool, Liverpool, L69 3BX, UK
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Ashby MC, Craske M, Park MK, Gerasimenko OV, Burgoyne RD, Petersen OH, Tepikin AV. Localized Ca2+ uncaging reveals polarized distribution of Ca2+-sensitive Ca2+ release sites: mechanism of unidirectional Ca2+ waves. J Cell Biol 2002; 158:283-92. [PMID: 12119355 PMCID: PMC2173122 DOI: 10.1083/jcb.200112025] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca2+-induced Ca2+ release (CICR) plays an important role in the generation of cytosolic Ca2+ signals in many cell types. However, it is inherently difficult to distinguish experimentally between the contributions of messenger-induced Ca2+ release and CICR. We have directly tested the CICR sensitivity of different regions of intact pancreatic acinar cells using local uncaging of caged Ca2+. In the apical region, local uncaging of Ca2+ was able to trigger a CICR wave, which propagated toward the base. CICR could not be triggered in the basal region, despite the known presence of ryanodine receptors. The triggering of CICR from the apical region was inhibited by a pharmacological block of ryanodine or inositol trisphosphate receptors, indicating that global signals require coordinated Ca2+ release. Subthreshold agonist stimulation increased the probability of triggering CICR by apical uncaging, and uncaging-induced CICR could activate long-lasting Ca2+ oscillations. However, with subthreshold stimulation, CICR could still not be initiated in the basal region. CICR is the major process responsible for global Ca2+ transients, and intracellular variations in sensitivity to CICR predetermine the activation pattern of Ca2+ waves.
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Affiliation(s)
- Michael C Ashby
- Medical Research Council Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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Cancela JM, Van Coppenolle F, Galione A, Tepikin AV, Petersen OH. Transformation of local Ca2+ spikes to global Ca2+ transients: the combinatorial roles of multiple Ca2+ releasing messengers. EMBO J 2002; 21:909-19. [PMID: 11867519 PMCID: PMC125894 DOI: 10.1093/emboj/21.5.909] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In pancreatic acinar cells, low, threshold concentrations of acetylcholine (ACh) or cholecystokinin (CCK) induce repetitive local cytosolic Ca2+ spikes in the apical pole, while higher concentrations elicit global signals. We have investigated the process that transforms local Ca2+ spikes to global Ca2+ transients, focusing on the interactions of multiple intracellular messengers. ACh-elicited local Ca2+ spikes were transformed into a global sustained Ca2+ response by cyclic ADP-ribose (cADPR) or nicotinic acid adenine dinucleotide phosphate (NAADP), whereas inositol 1,4,5-trisphosphate (IP3) had a much weaker effect. In contrast, the response elicited by a low CCK concentration was strongly potentiated by IP3, whereas cADPR and NAADP had little effect. Experiments with messenger mixtures revealed a local interaction between IP3 and NAADP and a stronger global potentiating interaction between cADPR and NAADP. NAADP strongly amplified the local Ca2+ release evoked by a cADPR/IP3 mixture eliciting a vigorous global Ca2+ response. Different combinations of Ca2+ releasing messengers can shape the spatio-temporal patterns of cytosolic Ca2+ signals. NAADP and cADPR are emerging as key messengers in the globalization of Ca2+ signals.
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MESH Headings
- Acetylcholine/pharmacology
- Adenosine Diphosphate Ribose/analogs & derivatives
- Adenosine Diphosphate Ribose/physiology
- Animals
- Caffeine/pharmacology
- Calcium Channels/drug effects
- Calcium Channels/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Cell Polarity
- Cholecystokinin/pharmacology
- Cyclic ADP-Ribose
- Exocytosis/drug effects
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate/physiology
- Inositol 1,4,5-Trisphosphate Receptors
- Mice
- NADP/analogs & derivatives
- NADP/pharmacology
- NADP/physiology
- Pancreas/cytology
- Patch-Clamp Techniques
- Receptors, Cell Surface/drug effects
- Receptors, Cell Surface/physiology
- Receptors, Cholecystokinin/drug effects
- Receptors, Cholecystokinin/physiology
- Receptors, Cholinergic/drug effects
- Receptors, Cholinergic/physiology
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/physiology
- Second Messenger Systems/physiology
- Sincalide/pharmacology
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Affiliation(s)
- Jose M. Cancela
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, Unité CNRS UPR 9040, 1 Avenue de la terrasse, 91 198 Gif-sur-Yvette,
Laboratoire de Physiologie Cellulaire, INSERM EPI 9938, Université de Lille I, France, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK Corresponding author e-mail:
| | - Fabien Van Coppenolle
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, Unité CNRS UPR 9040, 1 Avenue de la terrasse, 91 198 Gif-sur-Yvette,
Laboratoire de Physiologie Cellulaire, INSERM EPI 9938, Université de Lille I, France, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK Corresponding author e-mail:
| | - Antony Galione
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, Unité CNRS UPR 9040, 1 Avenue de la terrasse, 91 198 Gif-sur-Yvette,
Laboratoire de Physiologie Cellulaire, INSERM EPI 9938, Université de Lille I, France, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK Corresponding author e-mail:
| | - Alexei V. Tepikin
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, Unité CNRS UPR 9040, 1 Avenue de la terrasse, 91 198 Gif-sur-Yvette,
Laboratoire de Physiologie Cellulaire, INSERM EPI 9938, Université de Lille I, France, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK Corresponding author e-mail:
| | - Ole H. Petersen
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, Unité CNRS UPR 9040, 1 Avenue de la terrasse, 91 198 Gif-sur-Yvette,
Laboratoire de Physiologie Cellulaire, INSERM EPI 9938, Université de Lille I, France, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK Corresponding author e-mail:
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Fogarty KE, Kidd JF, Tuft DA, Thorn P. Mechanisms underlying InsP3-evoked global Ca2+ signals in mouse pancreatic acinar cells. J Physiol 2000; 526 Pt 3:515-26. [PMID: 10922004 PMCID: PMC2270036 DOI: 10.1111/j.1469-7793.2000.t01-1-00515.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In secretory epithelial cells, complex patterns of Ca2+ signals regulate physiological processes. How these patterns are generated is still not fully understood. In particular, the basis of global Ca2+ waves is not clear. We have studied regional differences in InsP3-evoked Ca2+ release in single mouse pancreatic acinar cells, using high-speed (approximately 90 frames s-1), high-sensitivity Ca2+ imaging combined with rapid (10 ms) spot photolysis (2 micrometer diameter) of caged InsP3. Within a single region we measured Ca2+ response latency and rate of rise to construct an InsP3 dose-response relationship. Spot InsP3 liberation in the secretory pole region consistently elicited a dose-dependent, rapid release of Ca2+. Spot InsP3 liberation in the basal pole region of approximately 50% of cells elicited a similar dose-response relationship but with a lower apparent InsP3 affinity than in the secretory pole. In the other cells, basal pole InsP3 liberation did not elicit active Ca2+ release, even at the highest stimulus intensities we employed, although these same cells did respond when the stimulus spot was moved to different regions. We conclude that in the basal pole active sites of rapid Ca2+ release have a lower functional affinity for InsP3 than those in the secretory pole and are spread out in discrete sites across the basal pole. These properties explain the propagation of Ca2+ waves across the basal pole that are only observed at higher stimulus levels.
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Affiliation(s)
- K E Fogarty
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1QJ, UK
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Camello PJ, Petersen OH, Toescu EC. Simultaneous presence of cAMP and cGMP exert a co-ordinated inhibitory effect on the agonist-evoked Ca2+ signal in pancreatic acinar cells. Pflugers Arch 1996; 432:775-81. [PMID: 8772126 DOI: 10.1007/s004240050198] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The stimulation of the pancreatic acinar cells by physiological secretagogues, such as acetycholine (ACh), activates a well-established intracellular signalling pathway, which involves the generation of Inositol 1,4,5-trisphosphate (InsP3) and the release of Ca2+ from intracellular stores. Caffeine, which inhibits this agonist-evoked Ca2+ response reversibly and competitively also blocks the Ca2+ signal generated by the non-specific activation of the membrane guanine nucleotide-binding proteins (G-proteins). Removal of caffeine is associated with an increase of intracellular [Ca2+] ([Ca2+]i) and the spatial and temporal characteristics of this Ca2+ signal are identical to those of the signal generated by the initial agonist stimulation. Caffeine is also a potent non-specific inhibitor of various cellular phosphodiesterases (PDE) and its inhibitory effect can be reproduced by other PDE inhibitors, chemically related (theophylline) or not (papaverine). Various protocols designed to increase the concentration of either of the major intracellular cyclic nucleotides [adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP)] failed to reproduce the full extent of the caffeine inhibition: at maximal agonist concentration (1 microM ACh) increases of either cAMP or cGMP did not affect the Ca2+ signal, whereas at submaximal doses of agonist (0.1-0.3 microM ACh) they induced partial inhibition. Here we show that only the simultaneous increase of the cellular concentrations of both cyclic nucleotides (either simultaneous or sequential) are effective in mimicking the blocking effect of caffeine and other non-specific PDE inhibitors. These data indicate, thus, that, in addition to other independent intracellular effects, cAMP and cGMP can exert a co-ordinated inhibitory effect of the agonist-evoked Ca2+ signal in pancreatic acinar cells.
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Affiliation(s)
- P J Camello
- Physiological Laboratory, Crown Street, PO Box 147, Liverpool L69 3BX, UK
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Toescu EC, Petersen OH. Region-specific activity of the plasma membrane Ca2+ pump and delayed activation of Ca2+ entry characterize the polarized, agonist-evoked Ca2+ signals in exocrine cells. J Biol Chem 1995; 270:8528-35. [PMID: 7721751 DOI: 10.1074/jbc.270.15.8528] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The initial release of Ca2+ from the intracellular Ca2+ stores is followed by a second phase during which the agonist-dependent Ca2+ response becomes sensitive to the extracellular Ca2+, indicating the involvement of the plasma membrane (PM) Ca2+ transport systems. The time course of activation of these transport systems, which consist of both Ca2+ extrusion and Ca2+ entry pathways, is not well established. To investigate the participation of these processes during the agonist-evoked Ca2+ response, isolated pancreatic acinar cells were exposed to maximal concentrations of an inositol 1,4,5-trisphosphate-mobilizing agonist (acetylcholine, 10 microM) in different experimental conditions. Following the increase of [Ca2+]i, there was an almost immediate activation of the PM Ca2+ extrusion system, and maximal activity was reached within less than 2s. The rate of Ca2+ extrusion was dependent on the level of [Ca2+]i, with a steep activation at values just above the resting [Ca2+]i and reached a plateau value at 700 nM Ca2+. In contrast, the PM Ca2+ entry pathway was activated with a much slower time course. There was also a delay of 3-4 s between the maximal effective depletion of the intracellular Ca2+ stores and the activation of this entry pathway. By use of digital imaging data, the PM Ca2+ transport systems were also analyzed independently in two regions of the cells, the lumenal and the basal poles. With respect to the activation of the Ca2+ entry pathways, no significant difference existed between these two regions. In contrast, the PM Ca2+ pump displayed a different pattern of activity in these regions. In the basal pole, the pump activity was more sensitive to changes of [Ca2+]i and had a higher maximal activity. Also, in the lumenal pole, the pump became saturated at values of [Ca2+]i around 700 nM, whereas at the basal pole [Ca2+]i had a biphasic effect on the pump activity, and higher [Ca2+]i inhibited the pump. It is argued that these differences in sensitivity to the levels of [Ca2+]i and the different relationship between [Ca2+]i and the rate of extrusion at the two functional poles of the pancreatic acinar cells indicate that the plasma membrane Ca2+ ATPase might play an important role in the polarization of the Ca2+ response.
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Affiliation(s)
- E C Toescu
- Physiological Laboratory, Liverpool University, United Kingdom
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