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Li S, Ji X, Gao M, Huang B, Peng S, Wu J. Endogenous Amyloid-formed Ca 2+-permeable Channels in Aged 3xTg AD Mice. FUNCTION 2023; 4:zqad025. [PMID: 37342418 PMCID: PMC10278988 DOI: 10.1093/function/zqad025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/13/2023] [Accepted: 05/25/2023] [Indexed: 06/22/2023] Open
Abstract
Alzheimer's disease (AD), the leading cause of dementia, is characterized by the accumulation of beta-amyloid peptides (Aβ). However, whether Aβ itself is a key toxic agent in AD pathogenesis and the precise mechanism of Aβ-elicited neurotoxicity are still debated. Emerging evidence demonstrates that the Aβ channel/pore hypothesis could explain Aβ toxicity, because Aβ oligomers are able to disrupt membranes and cause edge-conductivity pores that may disrupt cell Ca2+ homeostasis and drive neurotoxicity in AD. However, all available data to support this hypothesis have been collected from "in vitro" experiments using high concentrations of exogenous Aβ. It is still unknown whether Aβ channels can be formed by endogenous Aβ in AD animal models. Here, we report an unexpected finding of the spontaneous Ca2+ oscillations in aged 3xTg AD mice but not in age-matched wild-type mice. These spontaneous Ca2+ oscillations are sensitive to extracellular Ca2+, ZnCl2, and the Aβ channel blocker Anle138b, suggesting that these spontaneous Ca2+ oscillations in aged 3xTg AD mice are mediated by endogenous Aβ-formed channels.
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Affiliation(s)
- Shuangtao Li
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Xiaoyu Ji
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph’s Hospital and Medical Center, Phoenix, AZ 85013, USA
| | - Bing Huang
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Shuang Peng
- School of Sport and Health Sciences, Guangzhou Sport University, Guangzhou 510500, China
- Key Laboratory of Sports Technique, Tactics and Physical Function of General Administration of Sport of China, Scientific Research Center, Guangzhou Sport University, Guangzhou 510500, China
| | - Jie Wu
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph’s Hospital and Medical Center, Phoenix, AZ 85013, USA
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2
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Takano T, Yule DI. Ca 2+ signals in pancreatic acinar cells in response to physiological stimulation in vivo. J Physiol 2023. [PMID: 36965132 DOI: 10.1113/jp284469] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/08/2023] [Indexed: 03/27/2023] Open
Abstract
The exocrine pancreas secretes fluid and digestive enzymes in response to parasympathetic release of acetylcholine (ACh) via the vagus nerve and the gut hormone cholecystokinin (CCK). Both secretion of fluid and exocytosis of secretory granules containing enzymes and zymogens are dependent on an increase in the cytosolic [Ca2+ ] in acinar cells. It is thought that the specific spatiotemporal characteristics of the Ca2+ signals are fundamental for appropriate secretion and that these properties are disrupted in disease states in the pancreas. While extensive research has been performed to characterize Ca2+ signalling in acinar cells, this has exclusively been achieved in ex vivo preparations of exocrine cells, where it is difficult to mimic physiological conditions. Here we have developed a method to optically observe pancreatic acinar Ca2+ signals in vivo using a genetically expressed Ca2+ indicator and imaged with multi-photon microscopy in live animals. In vivo, acinar cells exhibited baseline activity in fasted animals, which was dependent on CCK1 receptors (CCK1Rs). Both stimulation of intrinsic nervous input and administration of systemic CCK induced oscillatory activity in a proportion of the cells, but the maximum frequencies were vastly different. Upon feeding, oscillatory activity was also observed, which was dependent on CCK1Rs. No evidence of a vago-vagal reflex mediating the effects of CCK was observed. Our in vivo method revealed the spatial and temporal profile of physiologically evoked Ca2+ signals, which will provide new insights into future studies of the mechanisms underlying exocrine physiology and that are disrupted in pathological conditions. KEY POINTS: In the exocrine pancreas, the spatiotemporal properties of Ca2+ signals are fundamentally important for the appropriate stimulation of secretion by the neurotransmitter acetylcholine and gut hormone cholecystokinin. These characteristics were previously defined in ex vivo studies. Here we report the spatiotemporal characteristics of Ca2+ signals in vivo in response to physiological stimulation in a mouse engineered to express a Ca2+ indicator in acinar cells. Specific Ca2+ 'signatures' probably important for stimulating secretion are evoked in vivo in fasted animals, by feeding, neural stimulation and cholecystokinin administration. The Ca2+ signals are probably the result of the direct action of ACh and CCK on acinar cells and not indirectly through a vago-vagal reflex.
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Affiliation(s)
- Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, USA
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3
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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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4
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Marolt U, Paradiž Leitgeb E, Pohorec V, Lipovšek S, Venglovecz V, Gál E, Ébert A, Menyhárt I, Potrč S, Gosak M, Dolenšek J, Stožer A. Calcium imaging in intact mouse acinar cells in acute pancreas tissue slices. PLoS One 2022; 17:e0268644. [PMID: 35657915 PMCID: PMC9165796 DOI: 10.1371/journal.pone.0268644] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/04/2022] [Indexed: 12/22/2022] Open
Abstract
The physiology and pathophysiology of the exocrine pancreas are in close connection to changes in intra-cellular Ca2+ concentration. Most of our knowledge is based on in vitro experiments on acinar cells or acini enzymatically isolated from their surroundings, which can alter their structure, physiology, and limit our understanding. Due to these limitations, the acute pancreas tissue slice technique was introduced almost two decades ago as a complementary approach to assess the morphology and physiology of both the endocrine and exocrine pancreas in a more conserved in situ setting. In this study, we extend previous work to functional multicellular calcium imaging on acinar cells in tissue slices. The viability and morphological characteristics of acinar cells within the tissue slice were assessed using the LIVE/DEAD assay, transmission electron microscopy, and immunofluorescence imaging. The main aim of our study was to characterize the responses of acinar cells to stimulation with acetylcholine and compare them with responses to cerulein in pancreatic tissue slices, with special emphasis on inter-cellular and inter-acinar heterogeneity and coupling. To this end, calcium imaging was performed employing confocal microscopy during stimulation with a wide range of acetylcholine concentrations and selected concentrations of cerulein. We show that various calcium oscillation parameters depend monotonically on the stimulus concentration and that the activity is rather well synchronized within acini, but not between acini. The acute pancreas tissue slice represents a viable and reliable experimental approach for the evaluation of both intra- and inter-cellular signaling characteristics of acinar cell calcium dynamics. It can be utilized to assess many cells simultaneously with a high spatiotemporal resolution, thus providing an efficient and high-yield platform for future studies of normal acinar cell biology, pathophysiology, and screening pharmacological substances.
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Affiliation(s)
- Urška Marolt
- Clinical department for abdominal and general surgery, University Medical Centre Maribor, Maribor, Slovenia
- * E-mail: (UM); (JD); (AS)
| | - Eva Paradiž Leitgeb
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Viljem Pohorec
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Saška Lipovšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor, Slovenia
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Eleonóra Gál
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Attila Ébert
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - István Menyhárt
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Stojan Potrč
- Clinical department for abdominal and general surgery, University Medical Centre Maribor, Maribor, Slovenia
| | - Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- * E-mail: (UM); (JD); (AS)
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- * E-mail: (UM); (JD); (AS)
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5
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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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6
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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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7
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8
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Yu WH, Wu E, Li Y, Hou HH, Yu SSC, Huang PT, Kuo WH, Qi D, Yu CJ. Matrix Metalloprotease-7 Mediates Nucleolar Assembly and Intra-nucleolar Cleaving p53 in Gefitinib-Resistant Cancer Stem Cells. iScience 2020; 23:101600. [PMID: 33089100 PMCID: PMC7559243 DOI: 10.1016/j.isci.2020.101600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/21/2020] [Accepted: 09/18/2020] [Indexed: 01/11/2023] Open
Abstract
The enlarged distinct bulky-ball-like nucleolus matrix assembly is observed in most cancer stem cells (CSCs); however, the underlying mechanism is largely unknown. We show that matrix metalloproteinase-7 (MMP-7) shedding MUC-1 SEA domain releases MUC-1 C-ter, facilitating the nucleolus trafficking of p53 in gefitinib-resistant lung CSCs. The nucleolus colocalizations of p53, MUC-1 C-ter, MMP-7 and nucleolin were observed in the CD34+ CXADR+ CD44v3+ gefitinib-resistant EGFRL858R/T790M CSC colonies. MUC-1 C-ter induced a unique porous bulky-ball-shaped, cagelike nucleolus that functions as a nucleus molecular “garage” for potent tumor suppressor, p53. Nucleolus could also facilitate the novel sub-nucleus compartment for proteolytic processing p53 by MMP-7 to generate a 35 kDa fragment. Moreover, we show that salinomycin, an anti-CSC agent, disrupts nucleolus by inducing nucleoplasm translocation of p53 and sensitizing CSC to chemotherapy drugs. Thus, this study highlights the MMP-7-MUC-1-p53 axis in nucleolus as a potential therapeutic target for anti-CSCs to resolve the chemotherapy-resistance dilemma. MMP-7 cleaves the SEA domain of MUC-1 and releases MUC-1 C-ter MUC-1 C-ter mediates bulky-ball-like nucleolus assembly trapping p53 in nucleolus MMP-7 cleaves p53 to 35 kDa fragments in the nucleolus of gefitinib-resistant CSCs Salinomycin induces p53 nucleoplasm translocation sensitizing CSCs to gefitinib
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Affiliation(s)
- Wei-Hsuan Yu
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan.,Molecular Image Center, College of Medicine. National Taiwan University, Taipei 10051, Taiwan
| | - Erxi Wu
- Neuroscience Institute and Department of Neurosurgery, Baylor Scott & White Health, Temple, TX 76508, USA.,Colleges of Medicine and Pharmacy, Texas A&M University, Health Science Center, College Station, TX 77843, USA.,Livestrong Cancer Institutes and Department of Oncology, Dell Medical School, the University of Texas at Austin, Austin, TX 78712, USA
| | - Yongqing Li
- Department of Surgery, University of Michigan Health Systems North Campus Research Complex, Ann Arbor, MI 48109, USA
| | - Hsin-Han Hou
- Graduate Institute of Oral Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Shuan-Su C Yu
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Po-Tsang Huang
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Wen-Hung Kuo
- Department of Surgery, National Taiwan University Hospital, Taipei 10048, Taiwan
| | - Dan Qi
- Neuroscience Institute and Department of Neurosurgery, Baylor Scott & White Health, Temple, TX 76508, USA
| | - Chong-Jen Yu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 10048, Taiwan
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9
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Schnipper J, Dhennin-Duthille I, Ahidouch A, Ouadid-Ahidouch H. Ion Channel Signature in Healthy Pancreas and Pancreatic Ductal Adenocarcinoma. Front Pharmacol 2020; 11:568993. [PMID: 33178018 PMCID: PMC7596276 DOI: 10.3389/fphar.2020.568993] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/16/2020] [Indexed: 12/11/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of cancer-related deaths in United States and Europe. It is predicted that PDAC will become the second leading cause of cancer-related deaths during the next decades. The development of PDAC is not well understood, however, studies have shown that dysregulated exocrine pancreatic fluid secretion can contribute to pathologies of exocrine pancreas, including PDAC. The major roles of healthy exocrine pancreatic tissue are secretion of enzymes and bicarbonate rich fluid, where ion channels participate to fine-tune these biological processes. It is well known that ion channels located in the plasma membrane regulate multiple cellular functions and are involved in the communication between extracellular events and intracellular signaling pathways and can function as signal transducers themselves. Hereby, they contribute to maintain resting membrane potential, electrical signaling in excitable cells, and ion homeostasis. Despite their contribution to basic cellular processes, ion channels are also involved in the malignant transformation from a normal to a malignant phenotype. Aberrant expression and activity of ion channels have an impact on essentially all hallmarks of cancer defined as; uncontrolled proliferation, evasion of apoptosis, sustained angiogenesis and promotion of invasion and migration. Research indicates that certain ion channels are involved in the aberrant tumor growth and metastatic processes of PDAC. The purpose of this review is to summarize the important expression, localization, and function of ion channels in normal exocrine pancreatic tissue and how they are involved in PDAC progression and development. As ion channels are suggested to be potential targets of treatment they are furthermore suggested to be biomarkers of different cancers. Therefore, we describe the importance of ion channels in PDAC as markers of diagnosis and clinical factors.
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Affiliation(s)
- Julie Schnipper
- Laboratory of Cellular and Molecular Physiology, UR-4667, University of Picardie Jules Verne, Amiens, France
| | - Isabelle Dhennin-Duthille
- Laboratory of Cellular and Molecular Physiology, UR-4667, University of Picardie Jules Verne, Amiens, France
| | - Ahmed Ahidouch
- Laboratory of Cellular and Molecular Physiology, UR-4667, University of Picardie Jules Verne, Amiens, France.,Department of Biology, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco
| | - Halima Ouadid-Ahidouch
- Laboratory of Cellular and Molecular Physiology, UR-4667, University of Picardie Jules Verne, Amiens, France
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10
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11
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Loppini A, Cherubini C, Bertolaso M, Filippi S. Breaking down calcium timing in heterogenous cells populations. Biosystems 2020; 191-192:104117. [DOI: 10.1016/j.biosystems.2020.104117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 01/17/2020] [Accepted: 02/12/2020] [Indexed: 12/21/2022]
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12
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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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13
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14
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Gryshchenko O, Gerasimenko JV, Peng S, Gerasimenko OV, Petersen OH. Calcium signalling in the acinar environment of the exocrine pancreas: physiology and pathophysiology. J Physiol 2018; 596:2663-2678. [PMID: 29424931 PMCID: PMC6046068 DOI: 10.1113/jp275395] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/25/2018] [Indexed: 12/12/2022] Open
Abstract
Key points Ca2+ signalling in different cell types in exocrine pancreatic lobules was monitored simultaneously and signalling responses to various stimuli were directly compared. Ca2+ signals evoked by K+‐induced depolarization were recorded from pancreatic nerve cells. Nerve cell stimulation evoked Ca2+ signals in acinar but not in stellate cells. Stellate cells are not electrically excitable as they, like acinar cells, did not generate Ca2+ signals in response to membrane depolarization. The responsiveness of the stellate cells to bradykinin was markedly reduced in experimental alcohol‐related acute pancreatitis, but they became sensitive to stimulation with trypsin. Our results provide fresh evidence for an important role of stellate cells in acute pancreatitis. They seem to be a critical element in a vicious circle promoting necrotic acinar cell death. Initial trypsin release from a few dying acinar cells generates Ca2+ signals in the stellate cells, which then in turn damage more acinar cells causing further trypsin liberation.
Abstract Physiological Ca2+ signals in pancreatic acinar cells control fluid and enzyme secretion, whereas excessive Ca2+ signals induced by pathological agents induce destructive processes leading to acute pancreatitis. Ca2+ signals in the peri‐acinar stellate cells may also play a role in the development of acute pancreatitis. In this study, we explored Ca2+ signalling in the different cell types in the acinar environment of the pancreatic tissue. We have, for the first time, recorded depolarization‐evoked Ca2+ signals in pancreatic nerves and shown that whereas acinar cells receive a functional cholinergic innervation, there is no evidence for functional innervation of the stellate cells. The stellate, like the acinar, cells are not electrically excitable as they do not generate Ca2+ signals in response to membrane depolarization. The principal agent evoking Ca2+ signals in the stellate cells is bradykinin, but in experimental alcohol‐related acute pancreatitis, these cells become much less responsive to bradykinin and then acquire sensitivity to trypsin. Our new findings have implications for our understanding of the development of acute pancreatitis and we propose a scheme in which Ca2+ signals in stellate cells provide an amplification loop promoting acinar cell death. Initial release of the proteases kallikrein and trypsin from dying acinar cells can, via bradykinin generation and protease‐activated receptors, induce Ca2+ signals in stellate cells which can then, possibly via nitric oxide generation, damage more acinar cells and thereby cause additional release of proteases, generating a vicious circle. Ca2+ signalling in different cell types in exocrine pancreatic lobules was monitored simultaneously and signalling responses to various stimuli were directly compared. Ca2+ signals evoked by K+‐induced depolarization were recorded from pancreatic nerve cells. Nerve cell stimulation evoked Ca2+ signals in acinar but not in stellate cells. Stellate cells are not electrically excitable as they, like acinar cells, did not generate Ca2+ signals in response to membrane depolarization. The responsiveness of the stellate cells to bradykinin was markedly reduced in experimental alcohol‐related acute pancreatitis, but they became sensitive to stimulation with trypsin. Our results provide fresh evidence for an important role of stellate cells in acute pancreatitis. They seem to be a critical element in a vicious circle promoting necrotic acinar cell death. Initial trypsin release from a few dying acinar cells generates Ca2+ signals in the stellate cells, which then in turn damage more acinar cells causing further trypsin liberation.
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Affiliation(s)
- Oleksiy Gryshchenko
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.,Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine
| | | | - Shuang Peng
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.,Department of Physiology, Medical College, Jinan University, Guangzhou 510632, China
| | | | - Ole H Petersen
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.,Systems Immunity Research Institute, Cardiff University, Cardiff, CF14 4XN, UK
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15
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Kim MJ, Choi KJ, Yoon MN, Oh SH, Kim DK, Kim SH, Park HS. Hydrogen peroxide inhibits Ca 2+ efflux through plasma membrane Ca 2+-ATPase in mouse parotid acinar cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018. [PMID: 29520174 PMCID: PMC5840080 DOI: 10.4196/kjpp.2018.22.2.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intracellular Ca2+ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide (H2O2) on cytosolic Ca2+ accumulation in mouse parotid acinar cells. Intracellular Ca2+ levels were slowly elevated when 1 mM H2O2 was perfused in the presence of normal extracellular Ca2+. In a Ca2+-free medium, 1 mM H2O2 still enhanced the intracellular Ca2+ level. Ca2+ entry tested using manganese quenching technique was not affected by perfusion of 1 mM H2O2. On the other hand, 10 mM H2O2 induced more rapid Ca2+ accumulation and facilitated Ca2+ entry from extracellular fluid. Ca2+ refill into intracellular Ca2+ store and inositol 1,4,5-trisphosphate (1 µM)-induced Ca2+ release from Ca2+ store was not affected by 1 mM H2O2 in permeabilized cells. Ca2+ efflux through plasma membrane Ca2+-ATPase (PMCA) was markedly blocked by 1 mM H2O2 in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected H2O2-induced Ca2+ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of H2O2 under pathological conditions may lead to cytosolic Ca2+ accumulation and that the primary mechanism of H2O2-induced Ca2+ accumulation is likely to inhibit Ca2+ efflux through PMCA rather than mobilize Ca2+ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.
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Affiliation(s)
- Min Jae Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Kyung Jin Choi
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Mi Na Yoon
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Sang Hwan Oh
- Department of Dental Hygiene, College of Medical Science, Konyang University, Daejeon 35365, Korea
| | - Dong Kwan Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Se Hoon Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Hyung Seo Park
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea.,Myunggok Medical Research Institute, Konyang University, Daejeon 35365, Korea
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16
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Petersen OH, Verkhratsky A. Calcium and ATP control multiple vital functions. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0418. [PMID: 27377728 DOI: 10.1098/rstb.2015.0418] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2016] [Indexed: 01/01/2023] Open
Abstract
Life on Planet Earth, as we know it, revolves around adenosine triphosphate (ATP) as a universal energy storing molecule. The metabolism of ATP requires a low cytosolic Ca(2+) concentration, and hence tethers these two molecules together. The exceedingly low cytosolic Ca(2+) concentration (which in all life forms is kept around 50-100 nM) forms the basis for a universal intracellular signalling system in which Ca(2+) acts as a second messenger. Maintenance of transmembrane Ca(2+) gradients, in turn, requires ATP-dependent Ca(2+) transport, thus further emphasizing the inseparable links between these two substances. Ca(2+) signalling controls the most fundamental processes in the living organism, from heartbeat and neurotransmission to cell energetics and secretion. The versatility and plasticity of Ca(2+) signalling relies on cell specific Ca(2+) signalling toolkits, remodelling of which underlies adaptive cellular responses. Alterations of these Ca(2+) signalling toolkits lead to aberrant Ca(2+) signalling which is fundamental for the pathophysiology of numerous diseases from acute pancreatitis to neurodegeneration. This paper introduces a theme issue on this topic, which arose from a Royal Society Theo Murphy scientific meeting held in March 2016.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Ole H Petersen
- Cardiff School of Biosciences and Systems Immunity Institute, Cardiff University, Cardiff CF10 3AX, Wales, UK
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, UK
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Abstract
BH3 mimetics are anticancer agents that reproduce the spatial arrangement of the BH3 domain of Bcl‐2 family proteins. Just like the BH3‐only proteins, these compounds bind to the hydrophobic cleft of the pro‐survival Bcl‐2 members such as Bcl‐2 or Bcl‐xL, and disrupt their heterodimerization with pro‐apoptotic Bax or Bak, sensitizing cells to chemotherapy. In recent years, it has become clear that Bcl‐2 family proteins are engaged in regulation of intracellular Ca2+ homeostasis, including Ca2+ release from the intracellular stores as well as Ca2+ fluxes across the plasma membrane. Given that BH3 mimetics shift the balance between the prosurvival and proapoptotic Bcl‐2 members, they might indirectly exert effects on intracellular Ca2+ signals. Indeed, it has been reported that some BH3 mimetics release Ca2+ from the intracellular stores causing Ca2+ overload in the cytosol. Therefore, the effects of any new BH3 mimetics on cellular Ca2+ homeostasis should be tested before these compounds progress to clinical trials. Drug Dev Res 78 : 313–318, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Pawel E Ferdek
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, CF10 3AX, United Kingdom
| | - Monika A Jakubowska
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, CF10 3AX, United Kingdom
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18
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Affiliation(s)
- Ole H Petersen
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Cardiff, UK.,Systems Immunity Research Institute, Cardiff University, Cardiff, UK
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Ferdek PE, Jakubowska MA. Biology of pancreatic stellate cells-more than just pancreatic cancer. Pflugers Arch 2017; 469:1039-1050. [PMID: 28382480 PMCID: PMC5554282 DOI: 10.1007/s00424-017-1968-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/13/2017] [Accepted: 03/16/2017] [Indexed: 01/18/2023]
Abstract
Pancreatic stellate cells, normally quiescent, are capable of remarkable transition into their activated myofibroblast-like phenotype. It is now commonly accepted that these cells play a pivotal role in the desmoplastic reaction present in severe pancreatic disorders. In recent years, enormous scientific effort has been devoted to understanding their roles in pancreatic cancer, which continues to remain one of the most deadly diseases. Therefore, it is not surprising that considerably less attention has been given to studying physiological functions of pancreatic stellate cells. Here, we review recent advances not only in the field of pancreatic stellate cell pathophysiology but also emphasise their roles in physiological processes.
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Affiliation(s)
- Pawel E Ferdek
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, CF10 3AX, UK.
| | - Monika A Jakubowska
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, CF10 3AX, UK
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Petersen OH, Courjaret R, Machaca K. Ca 2+ tunnelling through the ER lumen as a mechanism for delivering Ca 2+ entering via store-operated Ca 2+ channels to specific target sites. J Physiol 2017; 595:2999-3014. [PMID: 28181236 PMCID: PMC5430212 DOI: 10.1113/jp272772] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/05/2017] [Indexed: 01/02/2023] Open
Abstract
Ca2+ signalling is perhaps the most universal and versatile mechanism regulating a wide range of cellular processes. Because of the many different calcium‐binding proteins distributed throughout cells, signalling precision requires localized rises in the cytosolic Ca2+ concentration. In electrically non‐excitable cells, for example epithelial cells, this is achieved by primary release of Ca2+ from the endoplasmic reticulum via Ca2+ release channels placed close to the physiological target. Because any rise in the cytosolic Ca2+ concentration activates Ca2+ extrusion, and in order for cells not to run out of Ca2+, there is a need for compensatory Ca2+ uptake from the extracellular fluid. This Ca2+ uptake occurs through a process known as store‐operated Ca2+ entry. Ideally Ca2+ entering the cell should not diffuse to the target site through the cytosol, as this would potentially activate undesirable processes. Ca2+ tunnelling through the lumen of the endoplasmic reticulum is a mechanism for delivering Ca2+ entering via store‐operated Ca2+ channels to specific target sites, and this process has been described in considerable detail in pancreatic acinar cells and oocytes. Here we review the most important evidence and present a generalized concept.
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Affiliation(s)
- Ole H Petersen
- MRC Group, School of Biosciences and Systems Immunity Research Institute, Cardiff University, Cardiff, CF10 3AX, UK
| | - Raphael Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, PO Box 24144, Doha, Qatar
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, PO Box 24144, Doha, Qatar
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BH3 mimetic-elicited Ca 2+ signals in pancreatic acinar cells are dependent on Bax and can be reduced by Ca 2+-like peptides. Cell Death Dis 2017; 8:e2640. [PMID: 28252652 PMCID: PMC5386550 DOI: 10.1038/cddis.2017.41] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/20/2016] [Accepted: 01/11/2017] [Indexed: 02/07/2023]
Abstract
BH3 mimetics are small-molecule inhibitors of B-cell lymphoma-2 (Bcl-2) and Bcl-xL, which disrupt the heterodimerisation of anti- and pro-apoptotic Bcl-2 family members sensitising cells to apoptotic death. These compounds have been developed as anti-cancer agents to counteract increased levels of Bcl-2 proteins often present in cancer cells. Application of a chemotherapeutic drug supported with a BH3 mimetic has the potential to overcome drug resistance in cancers overexpressing anti-apoptotic Bcl-2 proteins and thus increase the success rate of the treatment. We have previously shown that the BH3 mimetics, BH3I-2' and HA14-1, induce Ca2+ release from intracellular stores followed by a sustained elevation of the cytosolic Ca2+ concentration. Here we demonstrate that loss of Bax, but not Bcl-2 or Bak, inhibits this sustained Ca2+ elevation. What is more, in the absence of Bax, thapsigargin-elicited responses were decreased; and in two-photon-permeabilised bax-/- cells, Ca2+ loss from the ER was reduced compared to WT cells. The Ca2+-like peptides, CALP-1 and CALP-3, which activate EF hand motifs of Ca2+-binding proteins, significantly reduced excessive Ca2+ signals and necrosis caused by two BH3 mimetics: BH3I-2' and gossypol. In the presence of CALP-1, cell death was shifted from necrotic towards apoptotic, whereas CALP-3 increased the proportion of live cells. Importantly, neither of the CALPs markedly affected physiological Ca2+ signals elicited by ACh, or cholecystokinin. In conclusion, the reduction in passive ER Ca2+ leak in bax-/- cells as well as the fact that BH3 mimetics trigger substantial Ca2+ signals by liberating Bax, indicate that Bax may regulate Ca2+ leak channels in the ER. This study also demonstrates proof-of-principle that pre-activation of EF hand Ca2+-binding sites by CALPs can be used to ameliorate excessive Ca2+ signals caused by BH3 mimetics and shift necrotic death towards apoptosis.
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Calcium-gated K+ channels of the KCa1.1- and KCa3.1-type couple intracellular Ca2+ signals to membrane hyperpolarization in mesenchymal stromal cells from the human adipose tissue. Pflugers Arch 2016; 469:349-362. [DOI: 10.1007/s00424-016-1932-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/10/2016] [Accepted: 12/14/2016] [Indexed: 01/06/2023]
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Gryshchenko O, Gerasimenko JV, Gerasimenko OV, Petersen OH. Ca(2+) signals mediated by bradykinin type 2 receptors in normal pancreatic stellate cells can be inhibited by specific Ca(2+) channel blockade. J Physiol 2015; 594:281-93. [PMID: 26442817 PMCID: PMC4713750 DOI: 10.1113/jp271468] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/30/2015] [Indexed: 01/05/2023] Open
Abstract
KEY POINTS Bradykinin may play a role in the autodigestive disease acute pancreatitis, but little is known about its pancreatic actions. In this study, we have investigated bradykinin-elicited Ca(2+) signal generation in normal mouse pancreatic lobules. We found complete separation of Ca(2+) signalling between pancreatic acinar (PACs) and stellate cells (PSCs). Pathophysiologically relevant bradykinin concentrations consistently evoked Ca(2+) signals, via B2 receptors, in PSCs but never in neighbouring PACs, whereas cholecystokinin, consistently evoking Ca(2+) signals in PACs, never elicited Ca(2+) signals in PSCs. The bradykinin-elicited Ca(2+) signals were due to initial Ca(2+) release from inositol trisphosphate-sensitive stores followed by Ca(2+) entry through Ca(2+) release-activated channels (CRACs). The Ca(2+) entry phase was effectively inhibited by a CRAC blocker. B2 receptor blockade reduced the extent of PAC necrosis evoked by pancreatitis-promoting agents and we therefore conclude that bradykinin plays a role in acute pancreatitis via specific actions on PSCs. ABSTRACT Normal pancreatic stellate cells (PSCs) are regarded as quiescent, only to become activated in chronic pancreatitis and pancreatic cancer. However, we now report that these cells in their normal microenvironment are far from quiescent, but are capable of generating substantial Ca(2+) signals. We have compared Ca(2+) signalling in PSCs and their better studied neighbouring acinar cells (PACs) and found complete separation of Ca(2+) signalling in even closely neighbouring PACs and PSCs. Bradykinin (BK), at concentrations corresponding to the slightly elevated plasma BK levels that have been shown to occur in the auto-digestive disease acute pancreatitis in vivo, consistently elicited substantial Ca(2+) signals in PSCs, but never in neighbouring PACs, whereas the physiological PAC stimulant cholecystokinin failed to evoke Ca(2+) signals in PSCs. The BK-induced Ca(2+) signals were mediated by B2 receptors and B2 receptor blockade protected against PAC necrosis evoked by agents causing acute pancreatitis. The initial Ca(2+) rise in PSCs was due to inositol trisphosphate receptor-mediated release from internal stores, whereas the sustained phase depended on external Ca(2+) entry through Ca(2+) release-activated Ca(2+) (CRAC) channels. CRAC channel inhibitors, which have been shown to protect PACs against damage caused by agents inducing pancreatitis, therefore also inhibit Ca(2+) signal generation in PSCs and this may be helpful in treating acute pancreatitis.
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Affiliation(s)
- Oleksiy Gryshchenko
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK.,Bogomoletz Institute of Physiology, Kiev, 01024, Ukraine
| | - Julia V Gerasimenko
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK
| | - Oleg V Gerasimenko
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK
| | - Ole H Petersen
- Medical Research Council Group, Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK
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Sahara Y, Horie S, Fukami H, Goto-Matsumoto N, Nakanishi-Matsui M. Functional roles of V-ATPase in the salivary gland. J Oral Biosci 2015. [DOI: 10.1016/j.job.2014.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ca2+ signaling in cytoskeletal reorganization, cell migration, and cancer metastasis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:409245. [PMID: 25977921 PMCID: PMC4421034 DOI: 10.1155/2015/409245] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/12/2015] [Indexed: 01/19/2023]
Abstract
Proper control of Ca2+ signaling is mandatory for effective cell migration, which is critical for embryonic development, wound healing, and cancer metastasis. However, how Ca2+ coordinates structural components and signaling molecules for proper cell motility had remained elusive. With the advance of fluorescent live-cell Ca2+ imaging in recent years, we gradually understand how Ca2+ is regulated spatially and temporally in migrating cells, driving polarization, protrusion, retraction, and adhesion at the right place and right time. Here we give an overview about how cells create local Ca2+ pulses near the leading edge, maintain cytosolic Ca2+ gradient from back to front, and restore Ca2+ depletion for persistent cell motility. Differential roles of Ca2+ in regulating various effectors and the interaction of roles of Ca2+ signaling with other pathways during migration are also discussed. Such information might suggest a new direction to control cancer metastasis by manipulating Ca2+ and its associating signaling molecules in a judicious manner.
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Congo red modulates ACh-induced Ca(2+) oscillations in single pancreatic acinar cells of mice. Acta Pharmacol Sin 2014; 35:1514-20. [PMID: 25345744 DOI: 10.1038/aps.2014.94] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/19/2014] [Indexed: 12/16/2022] Open
Abstract
AIM Congo red, a secondary diazo dye, is usually used as an indicator for the presence of amyloid fibrils. Recent studies show that congo red exerts neuroprotective effects in a variety of models of neurodegenerative diseases. However, its pharmacological profile remains unknown. In this study, we investigated the effects of congo red on ACh-induced Ca(2+) oscillations in mouse pancreatic acinar cells in vitro. METHODS Acutely dissociated pancreatic acinar cells of mice were prepared. A U-tube drug application system was used to deliver drugs into the bath. Intracellular Ca(2+) oscillations were monitored by whole-cell recording of Ca(2+)-activated Cl(-) currents and by using confocal Ca(2+) imaging. For intracellular drug application, the drug was added in pipette solution and diffused into cell after the whole-cell configuration was established. RESULTS Bath application of ACh (10 nmol/L) induced typical Ca(2+) oscillations in dissociated pancreatic acinar cells. Addition of congo red (1, 10, 100 μmol/L) dose-dependently enhanced Ach-induced Ca(2+) oscillations, but congo red alone did not induce any detectable response. Furthermore, this enhancement depended on the concentrations of ACh: congo red markedly enhanced the Ca(2+) oscillations induced by ACh (10-30 nmol/L), but did not alter the Ca(2+) oscillations induced by ACh (100-10000 nmol/L). Congo red also enhanced the Ca(2+) oscillations induced by bath application of IP3 (30 μmol/L). Intracellular application of congo red failed to alter ACh-induced Ca(2+) oscillations. CONCLUSION Congo red significantly modulates intracellular Ca(2+) signaling in pancreatic acinar cells, and this pharmacological effect should be fully considered when developing congo red as a novel therapeutic drug.
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Petersen OH. Calcium signalling and secretory epithelia. Cell Calcium 2014; 55:282-9. [PMID: 24508392 DOI: 10.1016/j.ceca.2014.01.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 01/10/2014] [Indexed: 12/15/2022]
Abstract
Ca(2+) is now firmly established as the most important intracellular regulator of physiological and pathological events in a vast number of different cell types, including secretory epithelia. In these tissues, Ca(2+) signalling is crucially important for the control of both fluid secretion and electrolyte secretion as well as the regulation of macromolecule secretion. In this overview article, I shall attempt to give some general background to the concepts underlying our current thinking about Ca(2+) signalling in epithelia and its roles in regulating secretion. It is outside the scope of this review to provide a comprehensive account of Ca(2+) signalling and the many different processes in the many different secretory epithelia that are controlled by Ca(2+) signals. It is my aim to draw attention to some general features of Ca(2+) signalling processes in secretory epithelia, which are rather different from those in, for example, endocrine glands. The principal examples will be taken from studies of exocrine cells and, in particular, pancreatic acinar cells, as they are the pioneer cells with regard to investigations of Ca(2+) signalling due to primary intracellular Ca(2+) release. They also represent the cell type which has been characterized in most detail with regard to Ca(2+) transport events and mechanisms.
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Affiliation(s)
- O H Petersen
- MRC Secretory Control Research Group, Cardiff School of Biosciences, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, Wales, UK.
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Manko BO, Manko VV. Mechanisms of respiration intensification of rat pancreatic acini upon carbachol-induced Ca(2+) release. Acta Physiol (Oxf) 2013; 208:387-99. [PMID: 23692873 DOI: 10.1111/apha.12119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 11/28/2012] [Accepted: 05/16/2013] [Indexed: 11/27/2022]
Abstract
AIM Acetylcholine as one of the main secretagogues modulates mitochondrial functions in acinar pancreacytes, presumably due to increase in ATP hydrolysis or Ca(2+) transport into mitochondria. The aim of this work was to investigate the mechanisms of carbachol (CCh) action on respiration and oxidative phosphorylation of isolated pancreatic acini. METHODS Respiration of intact or permeabilized rat pancreatic acini was studied at 37 °C using a Clark oxygen electrode. RESULTS Respiration rate of isolated acini in rest was 0.27 ± 0.01 nmol O2 s(-1) 10(-6) cells. Addition of 10 μM CCh into respiration chamber evoked biphasic stimulation of respiration. Rapid increase of respiration by 20.1% lasted for approx. 1 min, followed by decrease to level by 11.5% higher than control. Addition of 1 μm CCh caused monophasic increase by 11.5%. Preincubation (5 min) with 1 or 10 μm CCh elevated respiration rate by 12.5 or 11.2% respectively. FCCP prevented the effect of CCh. Preincubation with 1 (but not 10) μm CCh increased FCCP-uncoupled respiration rate. Thapsigargin slightly elevated respiration, but ryanodine did not. Application of 2-aminoethoxydiphenyl borate or ruthenium red prevented the effects of CCh on respiration, while oligomycin abolished them. Preincubation with 1 μm CCh prior to cell permeabilization increased respiration rate at pyruvate+malate oxidation, but not at succinate oxidation. In contrast, preincubation with 10 μm CCh decreased pyruvate+malate oxidation. CONCLUSION Medium CCh dose (1 μm) intensifies respiration and oxidative phosphorylation of acinar pancreacytes by feedforward mechanism via Ca(2+) transport into mitochondria and activation of Ca(2+) /ADP-sensitive mitochondrial dehydrogenases. Prolonged action of high CCh dose (10 μm) might impair mitochondrial functions.
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Affiliation(s)
- B. O. Manko
- Biology faculty; Department of Human and Animal Physiology Hrushevsky; Ivan Franko National university of Lviv; Lviv; Ukraine
| | - V. V. Manko
- Biology faculty; Department of Human and Animal Physiology Hrushevsky; Ivan Franko National university of Lviv; Lviv; Ukraine
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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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Ca2+ release-activated Ca2+ channel blockade as a potential tool in antipancreatitis therapy. Proc Natl Acad Sci U S A 2013; 110:13186-91. [PMID: 23878235 DOI: 10.1073/pnas.1300910110] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Alcohol-related acute pancreatitis can be mediated by a combination of alcohol and fatty acids (fatty acid ethyl esters) and is initiated by a sustained elevation of the Ca(2+) concentration inside pancreatic acinar cells ([Ca(2+)]i), due to excessive release of Ca(2+) stored inside the cells followed by Ca(2+) entry from the interstitial fluid. The sustained [Ca(2+)]i elevation activates intracellular digestive proenzymes resulting in necrosis and inflammation. We tested the hypothesis that pharmacological blockade of store-operated or Ca(2+) release-activated Ca(2+) channels (CRAC) would prevent sustained elevation of [Ca(2+)]i and therefore protease activation and necrosis. In isolated mouse pancreatic acinar cells, CRAC channels were activated by blocking Ca(2+) ATPase pumps in the endoplasmic reticulum with thapsigargin in the absence of external Ca(2+). Ca(2+) entry then occurred upon admission of Ca(2+) to the extracellular solution. The CRAC channel blocker developed by GlaxoSmithKline, GSK-7975A, inhibited store-operated Ca(2+) entry in a concentration-dependent manner within the range of 1 to 50 μM (IC50 = 3.4 μM), but had little or no effect on the physiological Ca(2+) spiking evoked by acetylcholine or cholecystokinin. Palmitoleic acid ethyl ester (100 μM), an important mediator of alcohol-related pancreatitis, evoked a sustained elevation of [Ca(2+)]i, which was markedly reduced by CRAC blockade. Importantly, the palmitoleic acid ethyl ester-induced trypsin and protease activity as well as necrosis were almost abolished by blocking CRAC channels. There is currently no specific treatment of pancreatitis, but our data show that pharmacological CRAC blockade is highly effective against toxic [Ca(2+)]i elevation, necrosis, and trypsin/protease activity and therefore has potential to effectively treat pancreatitis.
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The Exocrine Pancreas: The Acinar-Ductal Tango in Physiology and Pathophysiology. Rev Physiol Biochem Pharmacol 2013; 165:1-30. [DOI: 10.1007/112_2013_14] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Staiano RI, Granata F, Secondo A, Petraroli A, Loffredo S, Annunziato L, Triggiani M, Marone G. Human macrophages and monocytes express functional Na(+)/Ca (2+) exchangers 1 and 3. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:317-26. [PMID: 23224891 DOI: 10.1007/978-1-4614-4756-6_27] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Na(+)/Ca(2+) exchanger (NCX) is a plasma membrane protein that can switch Na(+) and Ca(2+) in either direction to maintain the homeostasis of intracellular Ca(2+). A family of three genes (NCX1, NCX2, and NCX3) has been identified in neurons and muscle cells. NCX activity has also been reported in certain immune cells (e.g., mast cells). We have examined the expression and function of these NCX isoforms in the human monocytes and lung macrophages. Monocytes were purified from peripheral blood of healthy donors. Macrophages (HLM) were isolated and purified from the lung parenchyma of patients undergoing thoracic surgery. NCX1 and NCX3, but not NCX2, were expressed in HLM and monocytes at both mRNA and protein level. Exposure to Na(+)-free medium induced a significant increase in intracellular calcium concentration ([Ca(2+)](i)) in both cell types, suggesting that NCX isoforms expressed on these cells were functionally active. This response was completely abolished by the NCX inhibitor 5-(N-4-chlorobenzyl)-20,40-dimethylbenzamil (CB-DMB). In addition, incubation of macrophages with Na(+)-free medium induced a marked release of TNF-α. Preincubation of HLM with CB-DMB and RNAi-mediated knockdown of NCX1 blocked TNF-α release. Our results demonstrate that human macrophages and monocytes express NCX1 and NCX3 that operate in a bidirectional manner to restore [Ca(2+)](i) to generate Ca(2+) signals and to induce TNF-α production. We suggest that NCX may modulate Ca(2+) homeostasis and proinflammatory functions in human macrophages and monocytes.
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Jin M, Hwang SM, Davies AJ, Shin Y, Bae JS, Lee JH, Lee EB, Song YW, Park K. Autoantibodies in primary Sjögren's syndrome patients induce internalization of muscarinic type 3 receptors. Biochim Biophys Acta Mol Basis Dis 2011; 1822:161-7. [PMID: 22137887 DOI: 10.1016/j.bbadis.2011.11.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/10/2011] [Accepted: 11/14/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by lymphocyte infiltration into the salivary and lachrymal glands, leading to dry mouth and eyes. The presence of functional autoantibodies against muscarinic type 3 receptor (M3R) has been reported in pSS patients. However, the pathological role of anti-M3R autoantibodies in pSS salivary dysfunction remains controversial. METHODS Purified IgGs were obtained from normal (control) and primary SS patients' sera (pSS IgG). Internalization of M3R and clathrin was analyzed by biochemical assay and immunofluorescence confocal microscopy using human submandibular gland (hSMG) cells. Cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) was measured by microspectrofluorimetry. RESULTS Incubation of hSMG cells with pSS IgG (1mg/ml) significantly decreased M3R expression levels at the membrane. Carbachol-induced [Ca(2+)](i) transients (CICTs) in these cells were also inhibited by pSS IgG. In contrast to pSS IgG, control IgG had no effect on both the M3R expression level and CICTs. We found that binding of pSS IgG to M3R induces phosphorylation of the receptor, and that the pSS IgG-induced M3R internalization is prevented by the lysosomal inhibitor, chloroquine. In addition, pSS IgG decreased membrane clathrin expression, which was inhibited by atropine. Our immunofluorescence study further confirmed that pSS IgG induces a co-localization of M3R with clathrin and subsequent internalization of M3R. CONCLUSION pSS IgG induces internalization of M3R partly through a clathrin-mediated pathway. The results suggest M3R internalization as a potential mechanism to explain the exocrinopathy seen in pSS patients.
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Affiliation(s)
- Meihong Jin
- Department of Physiology, College of Medicine, Seoul National University and Dental Research Institute, Seoul 110-749, Republic of Korea
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Booth DM, Mukherjee R, Sutton R, Criddle DN. Calcium and reactive oxygen species in acute pancreatitis: friend or foe? Antioxid Redox Signal 2011; 15:2683-98. [PMID: 21861696 PMCID: PMC3183657 DOI: 10.1089/ars.2011.3983] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Acute pancreatitis (AP) is a debilitating and, at times, lethal inflammatory disease, the causes and progression of which are incompletely understood. Disruption of Ca(2+) homeostasis in response to precipitants of AP leads to loss of mitochondrial integrity and cellular necrosis. RECENT ADVANCES While oxidative stress has been implicated as a major player in the pathogenesis of this disease, its precise roles remain to be defined. Recent developments are challenging the perception of reactive oxygen species (ROS) as nonspecific cytotoxic agents, suggesting that ROS promote apoptosis that may play a vital protective role in cellular stress since necrosis is avoided. CRITICAL ISSUES Fresh clinical findings have indicated that antioxidant treatment does not ameliorate AP and may actually worsen the outcome. This review explores the complex links between cellular Ca(2+) signaling and the intracellular redox environment, with particular relevance to AP. FUTURE DIRECTIONS Recent publications have underlined the importance of both Ca(2+) and ROS within the pathogenesis of AP, particularly in the determination of cell fate. Future research should elucidate the subtle interplay between Ca(2+) and redox mechanisms that operate to modulate mitochondrial function, with a view to devising strategies for the preservation of organellar function.
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Affiliation(s)
- David M Booth
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
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Jia YH, Cui ZJ. Tri-phasic modulation of ACh- and NA-maintained calcium plateau by high potassium in isolated mouse submandibular granular convoluted tubular cells. Arch Oral Biol 2011; 56:1347-55. [PMID: 21704303 DOI: 10.1016/j.archoralbio.2011.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/20/2011] [Accepted: 05/29/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The fact that submandibular glands secrete a large amount of potassium ion upon nerve stimulation has long been recognized, but a physiological role for such high potassium in the saliva has never been systematically investigated. In the present work, high potassium effect has been investigated in the freshly isolated mouse submandibular granular convoluted tubules. DESIGN Isolated intact mouse submandibular granular convoluted tubules were loaded with Fura-2, and cytosolic calcium concentration in individual tubular cells was measured by microscopic fluorospectrometry. RESULTS It was found that high potassium had no effect on basal cytosolic calcium concentration, but had a tri-phasic modulation of the calcium plateau maintained by continued stimulation by acetylcholine (ACh) or noradrenaline (NA): a minor initial transient depression, followed by steady increase, completed by a robust calcium rebound spike upon removal of high potassium. The phase of steady increase was blocked without major effect on the plateau by KB-R 7943, a sodium/calcium exchange (NCX) inhibitor. CONCLUSION These data together suggest that high potassium in saliva bathing the mouse submandibular granular convoluted tubular cells has a potent feedback effect on ACh and NA stimulation, and sodium/calcium exchange is likely to play a major role in this process. Such positive feedback actions of high potassium may suggest a role for enhancing ACh- or NA-stimulated protein factor secretion from the granulated convoluted tubular cells.
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Affiliation(s)
- Yan Hong Jia
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, China
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Yang RG, Xi N, Lai KWC, Zhong BH, Fung CKM, Qu CG, Wang DH. Nanomechanical analysis of insulinoma cells after glucose and capsaicin stimulation using atomic force microscopy. Acta Pharmacol Sin 2011; 32:853-60. [PMID: 21623392 DOI: 10.1038/aps.2011.56] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AIM Glucose stimulates insulin secretion from pancreatic islet β cells by altering ion channel activity and membrane potential in the β cells. TRPV1 channel is expressed in the β cells and capsaicin induces insulin secretion similarly to glucose. This study aims to investigate the biophysical properties of the β cells upon stimulation of membrane channels using an atomic force microscopic (AFM) nanoindentation system. METHODS ATCC insulinoma cell line was used. Cell stiffness, a marker of reorganization of cell membrane and cytoskeleton due to ion channel activation, was measured in real time using an integrated AFM nanoindentation system. Cell height that represented structural changes was simultaneously recorded along with cell stiffness. RESULTS After administration of glucose (16, 20 and 40 mmol/L), the cell stiffness was markedly increased in a dose-dependent manner, whereas cell height was changed in an opposite way. Lower concentrations of capsaicin (1.67 × 10(-9) and 1.67 × 10(-8) mol/L) increased the cell stiffness without altering cell height. In contrast, higher concentrations of capsaicin (1.67 × 10(-6) and 1.67 × 10(-7) mol/L) had no effect on the cell physical properties. CONCLUSION A unique bio-nanomechanical signature was identified for characterizing biophysical properties of insulinoma cells upon general or specific activation of membrane channels. This study may deepen our understanding of stimulus-secretion coupling of pancreatic islet cells that leads to insulin secretion.
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Tanimura A, Shitara A, Tojyo Y. Diversity and Spatio-Temporal Properties of Calcium Responses in Salivary Ducts. J Oral Biosci 2011. [DOI: 10.1016/s1349-0079(11)80035-6] [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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Berkefeld H, Fakler B, Schulte U. Ca2+-activated K+ channels: from protein complexes to function. Physiol Rev 2010; 90:1437-59. [PMID: 20959620 DOI: 10.1152/physrev.00049.2009] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Molecular research on ion channels has demonstrated that many of these integral membrane proteins associate with partner proteins, often versatile in their function, or even assemble into stable macromolecular complexes that ensure specificity and proper rate of the channel-mediated signal transduction. Calcium-activated potassium (K(Ca)) channels that link excitability and intracellular calcium concentration are responsible for a wide variety of cellular processes ranging from regulation of smooth muscle tone to modulation of neurotransmission and control of neuronal firing pattern. Most of these functions are brought about by interaction of the channels' pore-forming subunits with distinct partner proteins. In this review we summarize recent insights into protein complexes associated with K(Ca) channels as revealed by proteomic research and discuss the results available on structure and function of these complexes and on the underlying protein-protein interactions. Finally, the results are related to their significance for the function of K(Ca) channels under cellular conditions.
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Affiliation(s)
- Henrike Berkefeld
- Institute of Physiology II, University of Freiburg, and Centre for Biological Signalling Studies (Bioss),Freiburg, Germany.
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Oliynyk I, Varelogianni G, Roomans GM, Johannesson M. Effect of duramycin on chloride transport and intracellular calcium concentration in cystic fibrosis and non-cystic fibrosis epithelia. APMIS 2010; 118:982-90. [PMID: 21091780 DOI: 10.1111/j.1600-0463.2010.02680.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The lantibiotic duramycin (Moli1901, Lancovutide) has been suggested as a drug of choice in the treatment for cystic fibrosis (CF). It has been proposed that duramycin may stimulate chloride secretion through Ca²(+) -activated Cl⁻ channels (CaCC). We investigated whether duramycin exhibited any effect on Cl⁻ efflux and intracellular Ca²(+) concentration ([Ca²(+)](i)) in CF and non-CF epithelial cells. Duramycin did stimulate Cl⁻ efflux from CF bronchial epithelial cells (CFBE) in a narrow concentration range (around 1 μM). However, 100 and 250 μM of duramycin inhibited Cl⁻ efflux from CFBE cells. An inhibitor of the CF transmembrane conductance regulator (CFTR(inh)₋₁₇₂) and a blocker of the capacitative Ca²(+) entry, gadolinium chloride, inhibited the duramycin-induced Cl⁻ efflux. No effect on Cl⁻ efflux was observed in non-CF human bronchial epithelial cells (16HBE), human airway submucosal gland cell line, human pancreatic epithelial cells, CF airway submucosal gland epithelial cells, and CF pancreatic cells. The [Ca²(+)](i) was increased by 3 μM duramycin in 16HBE cells, but decreased after 1, and 3 μM of duramycin in CFBE cells. The results suggest that the mechanism responsible for the stimulation of Cl⁻ efflux by duramycin is mainly related to unspecific changes of the cell membrane or its components rather than to effects on CaCC.
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Affiliation(s)
- Igor Oliynyk
- Örebro University, Örebro University Hospital, Sweden.
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Han J, Liu YQ. Suppressed glucose metabolism in acinar cells might contribute to the development of exocrine pancreatic insufficiency in streptozotocin-induced diabetic mice. Metabolism 2010; 59:1257-67. [PMID: 20051281 DOI: 10.1016/j.metabol.2009.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 11/13/2009] [Accepted: 11/23/2009] [Indexed: 01/30/2023]
Abstract
High prevalence of exocrine pancreatic insufficiency has been observed in diabetic patients. However, the underlying mechanisms are not well known. Reduced cytosolic Ca(2+) signals in pancreatic acinar cells may contribute to lower digestive enzyme secretion. It is well known that adenosine triphosphate (ATP) regulates cytosolic Ca(2+) signals in acinar cells; however, little is known as to whether diabetes impairs glucose metabolism that produces ATP in acinar cells. Streptozotocin (STZ)-induced diabetic C57BL/6 mouse model was used. Four weeks after being diabetic, pancreatic acinar cells were isolated; and amylase secretion and contents, glucose utilization and oxidation, the activities of several key enzymes for glucose metabolism, and ATP and nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) contents were determined. Compared with controls, diabetic mice had lower body weight. Cholecystokinin-8- and acetylcholine-stimulated amylase secretion was significantly impaired, and total amylase activity in acinar cells of STZ-diabetic mice was markedly reduced. Glucose utilization and oxidation were suppressed; measured enzyme activities for glucose metabolism and the ATP and NADPH contents were significantly reduced. These data indicate that glucose metabolism and ATP and NADPH productions are very important for maintaining acinar cell normal function. Reduction of ATP (reduces cytosolic Ca(2+) signals) and NADPH (reduces cell capability for antioxidative stress) productions may contribute to the development of exocrine pancreatic insufficiency in STZ-diabetic mice.
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Affiliation(s)
- Junying Han
- The Research Institute for Children, Children's Hospital, New Orleans, Louisiana 70118, USA
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Li W, Shi YH, Yang RL, Cui J, Xiao Y, Le GW. Reactive oxygen species serve as signals mediating glucose-stimulated somatostatin secretion from cultured rat gastric primary D-cells. Free Radic Res 2010; 44:614-23. [PMID: 20370561 DOI: 10.3109/10715761003713549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Somatostatin plays an important role in glucose homeostasis. It is normally secreted in response to glucose and ATP generation is believed to be the key transduction signal of glucose-stimulated somatostatin secretion (GSSS). However, in the present study, in cultured rat gastric primary D-cells, GSSS was accompanied by increases in cellular reactive oxygen species (ROS). GSSS is dependent on the cellular ROS and independently of the ATP production linked to glucose metabolism. The antioxidant, alpha-lipoic acid or catalase inhibitor, 3-aminotriazole can influence the intracellular calcium concentration and abolish or further elevate GSSS. It is suggested that ROS production may serve as a signal modulating the necessary Ca(2+) recruitment for GSSS. Since somatostatin is thought to exert broad regulatory functions on gastrointestinal physiology and nutrient intake, the interaction with ROS may lead to potential targets for mediating nutrition and energy homeostasis.
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Affiliation(s)
- Wu Li
- State Key Lab of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, PR China
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Low JT, Shukla A, Thorn P. Pancreatic acinar cell: new insights into the control of secretion. Int J Biochem Cell Biol 2010; 42:1586-9. [PMID: 20637893 DOI: 10.1016/j.biocel.2010.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 07/08/2010] [Indexed: 12/21/2022]
Abstract
Pancreatic acinar cells secrete fluid and digestive enzymes. Both types of secretion are activated by a rise in intracellular calcium but how the stimulus-secretion cascade actually regulates secretory output is not well understood. It has long been known that the calcium response of acinar cells to physiological stimulation is complex. Dependent on the type and concentration of agonist, it consists of either local or global calcium increases as well as spreading waves of calcium across the cell. In the past it has been speculated that these different calcium signals drive different secretory responses. Now, recent employment of two-photon microscopy has enabled the simultaneous recording of both enzyme secretion and calcium signals and is beginning to resolve this issue. The data shows that local calcium responses exclusively drive fluid secretion. Where-as, global calcium responses drive both fluid and enzyme secretion. This differential control of secretory output is likely central to controlling the physiological responses of pancreatic acinar cells.
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Affiliation(s)
- Jiun T Low
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD, Australia
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Abstract
Since the first discovery of Kvbeta-subunits more than 15 years ago, many more ancillary Kv channel subunits were characterized, for example, KChIPs, KCNEs, and BKbeta-subunits. The ancillary subunits are often integral parts of native Kv channels, which, therefore, are mostly multiprotein complexes composed of voltage-sensing and pore-forming Kvalpha-subunits and of ancillary or beta-subunits. Apparently, Kv channels need the ancillary subunits to fulfill their many different cell physiological roles. This is reflected by the large structural diversity observed with ancillary subunit structures. They range from proteins with transmembrane segments and extracellular domains to purely cytoplasmic proteins. Ancillary subunits modulate Kv channel gating but can also have a great impact on channel assembly, on channel trafficking to and from the cellular surface, and on targeting Kv channels to different cellular compartments. The importance of the role of accessory subunits is further emphasized by the number of mutations that are associated in both humans and animals with diseases like hypertension, epilepsy, arrhythmogenesis, periodic paralysis, and hypothyroidism. Interestingly, several ancillary subunits have in vitro enzymatic activity; for example, Kvbeta-subunits are oxidoreductases, or modulate enzymatic activity, i.e., KChIP3 modulates presenilin activity. Thus different modes of beta-subunit association and of functional impact on Kv channels can be delineated, making it difficult to extract common principles underlying Kvalpha- and beta-subunit interactions. We critically review present knowledge on the physiological role of ancillary Kv channel subunits and their effects on Kv channel properties.
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Affiliation(s)
- Olaf Pongs
- Institut für Neurale Signalverarbeitung, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Universität Hamburg, Hamburg, Germany.
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Voronina S, Barrow S, Simpson A, Gerasimenko O, da Silva Xavier G, Rutter G, Petersen O, Tepikin AV. Dynamic changes in cytosolic and mitochondrial ATP levels in pancreatic acinar cells. Gastroenterology 2010; 138:1976-87. [PMID: 20102715 PMCID: PMC6101211 DOI: 10.1053/j.gastro.2010.01.037] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 12/17/2009] [Accepted: 01/21/2010] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS Previous studies of pancreatic acinar cells characterized the effects of Ca(2+)-releasing secretagogues and substances, inducing acute pancreatitis on mitochondrial Ca(2+), transmembrane potential, and NAD(P)H, but dynamic measurements of the crucial intracellular adenosine triphosphate (ATP) levels have not been reported. Here we characterized the effects of these agents on ATP levels in the cytosol and mitochondria. METHODS ATP levels were monitored using cytosolic- or mitochondrial-targeted luciferases. RESULTS Inhibition of oxidative phosphorylation produced a substantial decrease in cytosolic ATP comparable to that induced by inhibition of glycolysis. Cholecystokinin-8 (CCK) increased cytosolic ATP in spite of accelerating ATP consumption. Acetylcholine, caerulein, and bombesin had similar effect. A bile acid, taurolithocholic acid 3-sulfate (TLC-S); a fatty acid, palmitoleic acid (POA); and palmitoleic acid ethyl ester (POAEE) reduced cytosolic ATP. The ATP decrease in response to these substances was observed in cells with intact or inhibited oxidative phosphorylation. TLC-S, POA, and POAEE reduced mitochondrial ATP, whereas physiological CCK increased mitochondrial ATP. Supramaximal CCK produced a biphasic response composed of a small initial decline followed by a stronger increase. CONCLUSIONS Both glycolysis and oxidative phosphorylation make substantial contributions to ATP production in acinar cells. Ca(2+)-releasing secretagogues increased ATP level in the cytosol and mitochondria of intact isolated cells. TLC-S, POA, and POAEE reduced cytosolic and mitochondrial ATP. When cells rely on nonoxidative ATP production, secretagogues as well as TLC-S, POA, and POAEE all diminish cytosolic ATP levels.
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Affiliation(s)
- Svetlana Voronina
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Stephanie Barrow
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alec Simpson
- Department of Human Anatomy and Cell Biology, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Oleg Gerasimenko
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Gabriela da Silva Xavier
- Section of Cell Biology, Division of Medicine, Imperial College, London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, UK
| | - Guy Rutter
- Section of Cell Biology, Division of Medicine, Imperial College, London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, UK
| | - Ole Petersen
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Alexei V. Tepikin
- The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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Tight junctions in salivary epithelium. J Biomed Biotechnol 2010; 2010:278948. [PMID: 20182541 PMCID: PMC2825559 DOI: 10.1155/2010/278948] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/12/2009] [Accepted: 11/27/2009] [Indexed: 12/13/2022] Open
Abstract
Epithelial cell tight junctions (TJs) consist of a narrow belt-like structure in the apical region of the lateral plasma membrane that circumferentially binds each cell to its neighbor. TJs are found in tissues that are involved in polarized secretions, absorption functions, and maintaining barriers between blood and interstitial fluids. The morphology, permeability, and ion selectivity of TJ vary among different types of tissues and species. TJs are very dynamic structures that assemble, grow, reorganize, and disassemble during physiological or pathological events. Several studies have indicated the active role of TJ in intestinal, renal, and airway epithelial function; however, the functional significance of TJ in salivary gland epithelium is poorly understood. Interactions between different combinations of the TJ family (each with their own unique regulatory proteins) define tissue specificity and functions during physiopathological processes; however, these interaction patterns have not been studied in salivary glands. The purpose of this review is to analyze some of the current data regarding the regulatory components of the TJ that could potentially affect cellular functions of the salivary epithelium.
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Shitara A, Tanimura A, Sato A, Tojyo Y. Spontaneous oscillations in intracellular Ca(2+) concentration via purinergic receptors elicit transient cell swelling in rat parotid ducts. Am J Physiol Gastrointest Liver Physiol 2009; 297:G1198-205. [PMID: 19779019 DOI: 10.1152/ajpgi.00168.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Using multiphoton microscopy, we established that rat parotid ductal cells exhibit spontaneous oscillations in intracellular Ca(2+) concentration ([Ca(2+)](i)). These oscillatory Ca(2+) responses were observed during continuous perfusion with a physiological salt solution at 37 degrees C in the absence of calcium mobilizing agonist stimulation. The timing and patterns of these spontaneous Ca(2+) oscillations varied among individual ductal cells, and the average number of Ca(2+) responses in a single responding ductal cell was 2.1 in a 10-min recording period. High-speed scanning (0.6 s/image) revealed that most spontaneous elevations in [Ca(2+)](i) were initiated at the luminal side of ductal cells and spread toward the basal side within 2 s. Electron microscopic analysis after Ca(2+) imaging indicated that spontaneously oscillating ducts contained numerous granules at the luminal side, which is characteristic of granular ducts. These Ca(2+) oscillations were completely blocked by the purinergic receptor inhibitors 4-[[4-formyl-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-2-pyridinyl]azo]-1,3-benzenedisulfonic acid (PPADS) and suramin but were not blocked by the muscarinic antagonist atropine or the alpha-adrenergic antagonist phentolamine. Simultaneous observation of fura-2 fluorescence and differential interference contrast (DIC) images showed that spontaneous elevations of [Ca(2+)](i) were well correlated with changes in shape of ductal cells. Using a plasma membrane fluorescence probe, SynaptoGreen C4, we found that the changes in DIC images reflected spontaneous cell swelling of ductal cells. Our findings present the possibility that purinergic receptors mediate spontaneous Ca(2+) oscillations in parotid ductal cells and regulate electrolyte reabsorption from the primary saliva in the resting state.
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Affiliation(s)
- Akiko Shitara
- Dept. of Pharmacology, Health Sciences Univ. of Hokkaido, Japan
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Perc M, Rupnik M, Gosak M, Marhl M. Prevalence of stochasticity in experimentally observed responses of pancreatic acinar cells to acetylcholine. CHAOS (WOODBURY, N.Y.) 2009; 19:037113. [PMID: 19792038 DOI: 10.1063/1.3160017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Calcium ions play an important role in both intra- and intercellular signaling. In pancreatic acinar cells intracellular Ca(2+) regulates exocytotic secretion and fluid secretion. In this paper we study the typical experimental traces of Ca(2+) responses in pancreatic acinar cells obtained in response to the physiological agonist acetylcholine. To determine whether they are stochastic or deterministic in nature, we analyze the traces with methods of nonlinear time series analysis. In particular, by performing surrogate data tests and employing a determinism test for short time series, we show that the responses of pancreatic acinar cells to acetylcholine are stochastic with only faintly expressed deterministic features. Presented results thus corroborate the notion that mathematical models should take stochasticity explicitly into account when describing intra- and intercellular processes, and that indeed further efforts should be directed toward this subject.
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Affiliation(s)
- Matjaz Perc
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia.
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Staiano RI, Granata F, Secondo A, Petraroli A, Loffredo S, Frattini A, Annunziato L, Marone G, Triggiani M. Expression and function of Na+/Ca2+ exchangers 1 and 3 in human macrophages and monocytes. Eur J Immunol 2009; 39:1405-18. [DOI: 10.1002/eji.200838792] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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