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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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Jia Q, Du G, Li Y, Wang Z, Xie J, Gu J, Yin G, Zhang S, Gao Y, Zhou F, Feng C, Fan G. Pb 2+ modulates ryanodine receptors from the endoplasmic reticulum in rat brain. Toxicol Appl Pharmacol 2018; 338:103-111. [DOI: 10.1016/j.taap.2017.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 11/06/2017] [Accepted: 11/18/2017] [Indexed: 11/30/2022]
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3
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Xia K, Ma Z, Shen J, Li M, Hou B, Gao M, Zhang S, Wu J. The 2-aminoethoxydiphenyl borate analog, DPB161 blocks store-operated Ca 2+ entry in acutely dissociated rat submandibular cells. Oncotarget 2017; 8:61551-61560. [PMID: 28977884 PMCID: PMC5617444 DOI: 10.18632/oncotarget.18623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 05/06/2017] [Indexed: 02/05/2023] Open
Abstract
Cellular Ca2+ signals play a critical role in cell physiology and pathology. In most non-excitable cells, store-operated Ca2+ entry (SOCE) is an important mechanism by which intracellular Ca2+ signaling is regulated. However, few drugs can selectively modulate SOCE. 2-Aminoethoxydiphenyl borate (2APB) and its analogs (DPB162 and DPB163) have been reported to inhibit SOCE. Here, we examined the effects of another 2-APB analog, DPB161 on SOCE in acutely-isolated rat submandibular cells. Both patch-clamp recordings and Ca2+ imaging showed that upon removal of extracellular Ca2+ ([Ca2+]o=0), rat submandibular cells were unable to maintain ACh-induced Ca2+ oscillations, but restoration of [Ca2+]o to refill Ca2+ stores enable recovery of these Ca2+ oscillations. However, addition of 50 μM DPB161 with [Ca2+]o to extracellular solution prevented the refilling of Ca2+ store. Fura-2 Ca2+ imaging showed that DPB161 inhibited SOCE in a concentration-dependent manner. After depleting Ca2+ stores by thapsigargin treatment, bath perfusion of 1 mM Ca2+ induced [Ca2+]i elevation in a manner that was prevented by DPB161. Collectively, these results show that the 2-APB analog DPB161 blocks SOCE in rat submandibular cells, suggesting that this compound can be developed as a pharmacological tool for the study of SOCE function and as a new therapeutic agent for treating SOCE-associated disorders.
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Affiliation(s)
- Kunkun Xia
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Zegang Ma
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines, Physiology, Medical College of Qingdao University, Qingdao, China.,Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Jianxin Shen
- Department of Physiology, Shantou University Medical College, Shantou, China
| | - Menghan Li
- Department of Physiology, Shantou University Medical College, Shantou, China
| | - Baoke Hou
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Shuijun Zhang
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jie Wu
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA.,Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines, Physiology, Medical College of Qingdao University, Qingdao, China.,Department of Physiology, Shantou University Medical College, Shantou, China
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4
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Huang Z, Wang H, Wang J, Zhao M, Sun N, Sun F, Shen J, Zhang H, Xia K, Chen D, Gao M, Hammer RP, Liu Q, Xi Z, Fan X, Wu J. Cannabinoid receptor subtype 2 (CB2R) agonist, GW405833 reduces agonist-induced Ca(2+) oscillations in mouse pancreatic acinar cells. Sci Rep 2016; 6:29757. [PMID: 27432473 PMCID: PMC4949433 DOI: 10.1038/srep29757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/15/2016] [Indexed: 02/05/2023] Open
Abstract
Emerging evidence demonstrates that the blockade of intracellular Ca(2+) signals may protect pancreatic acinar cells against Ca(2+) overload, intracellular protease activation, and necrosis. The activation of cannabinoid receptor subtype 2 (CB2R) prevents acinar cell pathogenesis in animal models of acute pancreatitis. However, whether CB2Rs modulate intracellular Ca(2+) signals in pancreatic acinar cells is largely unknown. We evaluated the roles of CB2R agonist, GW405833 (GW) in agonist-induced Ca(2+) oscillations in pancreatic acinar cells using multiple experimental approaches with acute dissociated pancreatic acinar cells prepared from wild type, CB1R-knockout (KO), and CB2R-KO mice. Immunohistochemical labeling revealed that CB2R protein was expressed in mouse pancreatic acinar cells. Electrophysiological experiments showed that activation of CB2Rs by GW reduced acetylcholine (ACh)-, but not cholecystokinin (CCK)-induced Ca(2+) oscillations in a concentration-dependent manner; this inhibition was prevented by a selective CB2R antagonist, AM630, or was absent in CB2R-KO but not CB1R-KO mice. In addition, GW eliminated L-arginine-induced enhancement of Ca(2+) oscillations, pancreatic amylase, and pulmonary myeloperoxidase. Collectively, we provide novel evidence that activation of CB2Rs eliminates ACh-induced Ca(2+) oscillations and L-arginine-induced enhancement of Ca(2+) signaling in mouse pancreatic acinar cells, which suggests a potential cellular mechanism of CB2R-mediated protection in acute pancreatitis.
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MESH Headings
- Acetylcholine/pharmacology
- Acinar Cells/drug effects
- Acinar Cells/metabolism
- Acinar Cells/physiology
- Animals
- Arginine/pharmacology
- Calcium/metabolism
- Calcium Signaling/drug effects
- Cholinergic Agonists/pharmacology
- Indoles/pharmacology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Morpholines/pharmacology
- Pancreas/cytology
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
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Affiliation(s)
- Zebing Huang
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Haiyan Wang
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Jingke Wang
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Mengqin Zhao
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Nana Sun
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Fangfang Sun
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Jianxin Shen
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Haiying Zhang
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Kunkun Xia
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Dejie Chen
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Ming Gao
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
| | - Ronald P. Hammer
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
- Departments of Pharmacology and Psychiatry University of Arizona College of Medicine Tucson, AZ, 85721, USA
| | - Qingrong Liu
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Zhengxiong Xi
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Xuegong Fan
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
| | - Jie Wu
- Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Hunan Province, Changsha 410008, China
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix AZ 85013, USA
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515041, China
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
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5
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Zhu Z, Tang J, Zhou X, Xiang S, Zhu X, Li N, Shi R, Zhong Y, Zhang L, Sun M, Xu Z. Roles of ion channels in regulation of acetylcholine-mediated vasoconstrictions in umbilical cords of rabbit/rats. Reprod Toxicol 2016; 65:95-103. [PMID: 27421582 DOI: 10.1016/j.reprotox.2016.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/31/2016] [Accepted: 07/08/2016] [Indexed: 12/25/2022]
Abstract
We recently demonstrated that acetylcholine (ACh) produced reliable vasoconstrictions in the umbilical cords. This study investigated the possible mechanisms with different antagonists. ACh-mediated vasoconstrictions were decreased by voltage-operated calcium (Ca2+) channels antagonist nifedipine or inositol-1,4,5-trisphosphate-mediated Ca2+ release antagonist 2-aminoethyl diphenylborinate, indicating that both extracellular and intracellular calcium modulated the ACh-stimulated umbilical contraction. Intracellular Ca2+ concentrations were increased simultaneously with vasoconstrictions by ACh in the umbilical vessels. Inhibiting large-conductance calcium-dependent potassium (BK) channels enhanced ACh-mediated contraction, whereas inhibiting voltage dependent potassium (K+), inward rectifier K+ and ATP-sensitive K+ channels had no effects. Incubation with specific K+ channel inhibitors showed that ACh suppressed BK currents rather than 4-aminopyridine-sensitive K+ channels currents. The results suggested that blood vessels in umbilical cords had special characteristics in response to cholinergic signals. ACh-stimulated umbilical vasoconstrictions were mediated via muscarinic receptor subtype 1/3-protein kinase C/cyclooxygenase-BK channel pathways.
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Affiliation(s)
- Zhoufeng Zhu
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Jiaqi Tang
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Xiuwen Zhou
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Sharon Xiang
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China; Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA
| | - Xiaolin Zhu
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Na Li
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Ruixiu Shi
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Yuan Zhong
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Lubo Zhang
- Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA
| | - Miao Sun
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China.
| | - Zhice Xu
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou 215006, China; Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA.
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6
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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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7
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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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8
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Akay Y, Dragomir A, Chuanze Song, Jie Wu, Akay M. Hippocampal gamma oscillations in rats. ACTA ACUST UNITED AC 2009; 28:92-5. [DOI: 10.1109/memb.2009.934619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Abstract
Calcium signals mediate diverse cellular functions in immunological cells. Early studies with mast cells, then a preeminent model for studying Ca2+-dependent exocytosis, revealed several basic features of calcium signaling in non-electrically excitable cells. Subsequent studies in these and other cells further defined the basic processes such as inositol 1,4,5-trisphosphate-mediated release of Ca2+ from Ca2+ stores in the endoplasmic reticulum (ER); coupling of ER store depletion to influx of external Ca2+ through a calcium-release activated calcium (CRAC) channel now attributed to the interaction of the ER Ca2+ sensor, stromal interacting molecule-1 (STIM1), with a unique Ca2+-channel protein, Orai1/CRACM1, and subsequent uptake of excess Ca2+ into ER and mitochondria through ATP-dependent Ca2+ pumps. In addition, transient receptor potential channels and ion exchangers also contribute to the generation of calcium signals that may be global or have dynamic (e.g., waves and oscillations) and spatial resolution for specific functional readouts. This review discusses past and recent developments in this field of research, the pharmacologic agents that have assisted in these endeavors, and the mast cell as an exemplar for sorting out how calcium signals may regulate multiple outputs in a single cell.
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Affiliation(s)
- Hong-Tao Ma
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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10
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Akay YM, Dragomir A, Wu J, Akay M. The effects of 2-APB on the time-frequency distributions of gamma oscillations in rat hippocampal slices. J Neural Eng 2009; 6:056006. [PMID: 19717894 DOI: 10.1088/1741-2560/6/5/056006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated the influence of 2-APB (2-aminoethoxy-diphenylborate) acute exposure on hippocampal oscillations using time-frequency analysis methods including continuous wavelet transform and short-time Fourier transform. We hypothesized that acute exposure to 2-APB drastically reduced the hippocampal gamma oscillations. We estimated the hippocampal oscillations' time-frequency representations from 24 hippocampal slices in five rats. Our results indicated that it took at least 100 ms to see any hippocampal activities in response to the 100 Hz stimulus. The hippocampal oscillations' spectral energies dominated in the 31-60 Hz and 61-90 Hz frequency bands in the early time (100-200 ms) segment post-stimulus and in the 31-60 Hz and 61-90 Hz frequency bands after 200 ms until 400 ms post-stimulus. They were noticeably reduced in the late time segment (above 400 ms). The hippocampal oscillations' spectral energies in the 31-60 and 61-90 Hz frequency bands still dominated the early time segment after the acute 2-APB exposure. The 2-APB exposure never changed the energy content in all three frequency bands in the early time segment (p > 0.01). The exposure significantly reduced the energy content in both the mid-time segment and in the 31-60 Hz frequency band (p < 0.001) and in both the second time segment and in the 61-90 Hz frequency band (p < 0.01). Additionally, in the late time segment, the energy content in all three frequency bands was notably reduced post-drug exposure (p < 0.001).
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11
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Valerio P, Pereira MM, Goes AM, Leite MF. Effects of extracellular calcium concentration on the glutamate release by bioactive glass (BG60S) preincubated osteoblasts. Biomed Mater 2009; 4:045011. [PMID: 19636109 DOI: 10.1088/1748-6041/4/4/045011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Glutamate released by osteoblasts sharing similarities with its role in neuronal transmission is a very new scientific concept which actually changed the understanding of bone physiology. Since glutamate release is a calcium (Ca(2+))-dependent process and considering that we have previously demonstrated that the dissolution of bioactive glass with 60% of silicon (BG60S) can alter osteoblast Ca(2+)-signaling machinery, we investigated whether BG60S induces glutamate secretion in osteoblasts and whether it requires an increase in intracellular Ca(2+). Here we showed that the extracellular Ca(2+) increase due to BG60S dissolution leads to an intracellular Ca(2+) increase in the osteoblast, through the activation of an inositol 1,4,5-triphosphate receptor (InsP(3)R) and a ryanodine receptor (RyR). Additionally, we also demonstrated that glutamate released by osteoblasts can be profoundly altered by BG60S. The modulation of osteoblast glutamate released by the extracellular Ca(2+) concentration opens a new window in the field of tissue engineering, since many biomaterials used for bone repair are able to increase the extracellular Ca(2+) concentration due to their dissolution products.
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Affiliation(s)
- P Valerio
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Brazil.
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12
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Natriuretic peptides as regulatory mediators of secretory activity in the digestive system. ACTA ACUST UNITED AC 2009; 154:5-15. [PMID: 19233231 DOI: 10.1016/j.regpep.2009.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/28/2009] [Accepted: 02/03/2009] [Indexed: 11/22/2022]
Abstract
Atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) are members of the natriuretic peptide family best known for their role in blood pressure regulation. However, in recent years all the natriuretic peptides and their receptors have been described in the gastrointestinal tract, digestive glands and central nervous system, as well as implicated in the regulation of digestive gland functions. The current review highlights the regulatory role of ANP and CNP in pancreatic and other digestive secretions. ANP and CNP stimulate basal as well as induced pancreatic secretion and modify bicarbonate and chloride secretions. Whereas ANP and CNP exert effects directly on pancreatic cells, CNP also acts through a vago-vagal reflex. At high doses both peptides attenuate pancreatic secretion induced by high doses of secretin through the PLC/PKC pathway. With regards to other digestive secretions, ANP and CNP decrease bile secretion in the rat. ANP does not induce salivation by itself but enhances stimulated salivary secretion and modifies salivary composition in rat parotid as well as submandibular glands. In rat pancreatic, hepatic, parotid and submandibular tissues, the NPR-C receptor mediates mostly peripheral responses whereas NPR-A and NPR-B receptors, which are coupled to guanylate cyclase, likely mediate the central response. In addition, ANP modulates gastric acid secretion via a vagal-dependent mechanism. In the intestine, ANP and CNP decrease water and sodium chloride absorption through an increase in cGMP levels. Overall, these findings indicate that ANP and CNP are members of the large group of regulatory peptides affecting digestive secretions.
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Abstract
Arrhythmias arise from a complex interaction between structural changes in the myocardium and changes in cellular electrophysiology. Electrophysiological balance requires precise control of sarcolemmal ion channels and exchangers, many of which are regulated by phospholipid, phosphatidylinositol(4,5)bisphosphate. Phosphatidylinositol(4,5)bisphosphate is the immediate precursor of inositol(1,4,5)trisphosphate, a regulator of intracellular Ca2+ signalling and, therefore, a potential contributor to arrhythmogenesis by altering Ca2+ homeostasis. The aim of the present review is to outline current evidence that this signalling pathway can be a player in the initiation or maintenance of arrhythmias.
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Affiliation(s)
- Elizabeth A Woodcock
- Molecular Cardiology Laboratory, Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Road Central, Melbourne, 8008 Victoria, Australia.
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14
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Sabbatini ME, Rodríguez M, di Carlo MB, Davio CA, Vatta MS, Bianciotti LG. C-type natriuretic peptide enhances amylase release through NPR-C receptors in the exocrine pancreas. Am J Physiol Gastrointest Liver Physiol 2007; 293:G987-94. [PMID: 17702953 DOI: 10.1152/ajpgi.00268.2007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several studies show that C-type natriuretic peptide (CNP) has a modulatory role in the digestive system. CNP administration reduces both jejunal fluid and bile secretion in the rat. In the present study we evaluated the effect of CNP on amylase release in isolated pancreatic acini as well as the receptors and intracellular pathways involved. Results showed that all natriuretic peptide receptors were expressed not only in the whole pancreas but also in isolated pancreatic acini. CNP stimulated amylase secretion with a concentration-dependent biphasic response; maximum release was observed at 1 pM CNP, whereas higher concentrations gradually attenuated it. The response was mimicked by a selective natriuretic peptide receptor (NPR-C) agonist and inhibited by pertussis toxin, strongly supporting NPR-C receptor activation. CNP-evoked amylase release was abolished by U-73122 (PLC inhibitor) and 2-aminoethoxydiphenyl borate (2-APB) [an inositol 1,4,5-triphosphate (IP(3)) receptor antagonist], partially inhibited by GF-109203X (PKC inhibitor), and unaltered by ryanodine or protein kinase A (PKA) and protein kinase G (PKG) inhibitors. Phosphoinositide hydrolysis was enhanced by CNP at all concentrations and abolished by U-73122. At 1 and 10 pM, CNP did not affect cAMP or guanosine 3',5'-cyclic monophosphate (cGMP) levels, but at higher concentrations it increased cGMP and diminished cAMP content. Present findings show that CNP stimulated amylase release through the activation of NPR-C receptors coupled to the PLC pathway and downstream effectors involved in exocytosis. The attenuation of amylase release was likely related to cAMP reduction. The augmentation in cGMP supports activation of NPR-A/NPR-B receptors probably involved in calcium influx. Present findings give evidence that CNP is a potential direct regulator of pancreatic function.
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Affiliation(s)
- María E Sabbatini
- Cátedra de Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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15
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Cervia D, Martini D, Garcia-Gil M, Di Giuseppe G, Guella G, Dini F, Bagnoli P. Cytotoxic effects and apoptotic signalling mechanisms of the sesquiterpenoid euplotin C, a secondary metabolite of the marine ciliate Euplotes crassus, in tumour cells. Apoptosis 2006; 11:829-43. [PMID: 16534550 DOI: 10.1007/s10495-006-5700-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Most antitumour agents with cytotoxic properties induce apoptosis. The lipophilic compound euplotin C, isolated from the ciliate Euplotes crassus, is toxic to a number of different opportunistic or pathogenic microorganisms, although its mechanism of action is currently unknown. We report here that euplotin C is a powerful cytotoxic and pro-apoptotic agent in mouse AtT-20 and rat PC12 tumour-derived cell lines. In addition, we provide evidence that euplotin C treatment results in rapid activation of ryanodine receptors, depletion of Ca2+ stores in the endoplasmic reticulum (ER), the release of cytochrome c from the mitochondria, activation of caspase-12, and activation of caspase-3, leading to apoptosis. Intracellular Ca2+ overload is an early event which induces apoptosis and is parallelled by ER stress and the release of cytochrome c, whereas caspase-12 may be activated by euplotin C at a later stage in the apoptosis pathway. These events, either independently or concomitantly, lead to the activation of the caspase-3 and its downstream effectors, triggering the cell to undergo apoptosis. These results demonstrate that euplotin C may be considered for the design of cytotoxic and pro-apoptotic new drugs.
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Affiliation(s)
- D Cervia
- Dipartimento di Fisiologia e Biochimica G. Moruzzi, via S. Zeno, 56127, Pisa, Italy.
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16
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Bose DD, Thomas DW. 2-Aminoethoxydiphenyl borate (2-APB) stimulates a conformationally coupled calcium release pathway in the NG115-401L neuronal cell line. Neuropharmacology 2005; 50:532-9. [PMID: 16325870 DOI: 10.1016/j.neuropharm.2005.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 09/28/2005] [Accepted: 10/21/2005] [Indexed: 11/30/2022]
Abstract
We report in this study a 2-aminoethoxydiphenyl borate (2-APB) activated Ca2+ pathway in NG115-401L (401L) neuronal cells bearing resemblance to hormonal and ryanodine receptor activated pathways. We observed that 2-APB, in contrast to much earlier work, did not inhibit store operated Ca2+ channel (SOC) function, but rather induced potent Ca2+ discharge responses that robustly activated SOC-mediated Ca2+ influx. Further, these studies intriguingly revealed that the 2-APB-induced Ca2+ release pathway likely couples conformationally to targets in the plasma membrane, as membrane permeabilization or actin perturbation abolished the ability of the compound to stimulate Ca2+ signals. These findings suggest that conformationally sensitive complexes form between endoplasmic reticulum and plasma membrane components that not only regulate Ca2+ influx, previously proposed as the conformational coupling hypothesis, but are also required to promote Ca2+ release from intracellular stores. These observations further characterize the 401L neuronal cell line as having unique characteristics that may prove useful in gaining insight into the nature of the coupling mechanism linking Ca2+ release to Ca2+ influx.
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Affiliation(s)
- Diptiman D Bose
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
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17
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Thore S, Dyachok O, Gylfe E, Tengholm A. Feedback activation of phospholipase C via intracellular mobilization and store-operated influx of Ca2+ in insulin-secreting β-cells. J Cell Sci 2005; 118:4463-71. [PMID: 16159958 DOI: 10.1242/jcs.02577] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phospholipase C (PLC) regulates various cellular processes by catalyzing the formation of inositol-1,4,5-trisphosphate (IP3) and diacylglycerol from phosphatidylinositol-4,5-bisphosphate (PIP2). Here, we have investigated the influence of Ca2+ on receptor-triggered PLC activity in individual insulin-secreting β-cells. Evanescent wave microscopy was used to record PLC activity using green fluorescent protein (GFP)-tagged PIP2/IP3-binding pleckstrin homology domain from PLCδ1, and the cytoplasmic Ca2+ concentration ([Ca2+]i) was simultaneously measured using the indicator Fura Red. Stimulation of MIN6 β-cells with the muscarinic-receptor agonist carbachol induced rapid and sustained PLC activation. By contrast, only transient activation was observed after stimulation in the absence of extracellular Ca2+ or in the presence of the non-selective Ca2+ channel inhibitor La3+. The Ca2+-dependent sustained phase of PLC activity did not require voltage-gated Ca2+ influx, as hyperpolarization with diazoxide or direct Ca2+ channel blockade with nifedipine had no effect. Instead, the sustained PLC activity was markedly suppressed by the store-operated channel inhibitors 2-APB and SKF96365. Depletion of intracellular Ca2+ stores with the sarco(endo)plasmic reticulum Ca2+-ATPase inhibitors thapsigargin or cyclopiazonic acid abolished Ca2+ mobilization in response to carbachol, and strongly suppressed the PLC activation in Ca2+-deficient medium. Analogous suppressions were observed after loading cells with the Ca2+ chelator BAPTA. Stimulation of primary mouse pancreatic β-cells with glucagon elicited pronounced [Ca2+]i spikes, reflecting protein kinase A-mediated activation of Ca2+-induced Ca2+ release via IP3 receptors. These [Ca2+]i spikes were found to evoke rapid and transient activation of PLC. Our data indicate that receptor-triggered PLC activity is enhanced by positive feedback from Ca2+ entering the cytoplasm from intracellular stores and via store-operated channels in the plasma membrane. Such amplification of receptor signalling should be important in the regulation of insulin secretion by hormones and neurotransmitters.
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Affiliation(s)
- Sophia Thore
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-75123 Uppsala, Sweden
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18
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Padar S, Bose DD, Livesey JC, Thomas DW. 2-Aminoethoxydiphenyl borate perturbs hormone-sensitive calcium stores and blocks store-operated calcium influx pathways independent of cytoskeletal disruption in human A549 lung cancer cells. Biochem Pharmacol 2005; 69:1177-86. [PMID: 15794938 DOI: 10.1016/j.bcp.2005.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2004] [Accepted: 01/24/2005] [Indexed: 11/24/2022]
Abstract
Recent studies have identified novel actions for 2-aminoethoxydiphenyl borate (2-APB) in triggering calcium release and enhancing calcium influx induced by the depletion of intracellular calcium stores. In this study, we have examined the effects of 2-APB on the human lung adenocarcinoma A549 cell line, which we have previously shown displays a unique calcium influx response, when ER calcium stores are depleted by thapsigargin (TG) treatment. Here, we show that low concentrations of 2-APB failed to induce the rapid augmentation of TG-activated calcium influx previously reported for other cell types. We observed that store-operated calcium (SOC) channels in the A549 cell line exhibited short-term sensitivity to low doses of 2-APB, perhaps reflecting a delayed augmentation of SOC channel activity or the recruitment of 2-APB-insensitive SOC channels. In both intact and permeabilized cells, 2-APB effectively discharged a subset of A549 calcium pools corresponding to the hormone-sensitive intracellular calcium stores. The 2-APB-induced calcium release produced a long-lasting perturbation of the adenosine triphosphate (ATP)-releasable calcium pools, effectively uncoupling ATP-activated calcium release even, when stores are replenished with calcium. In contrast to previous reports, we found that disruption of either the actin or microtubule-based cytoskeleton failed to block the 2-APB-induced effects on calcium signaling in A549 cells. Our study describes novel cytoskeletal-independent effects of 2-APB on Ca2+-signaling pathways, revealing differentially sensitive Ca2+-influx pathways and long-term perturbation of hormone-sensitive Ca2+ stores.
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Affiliation(s)
- Shanthala Padar
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
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Mignen O, Thompson JL, Yule DI, Shuttleworth TJ. Agonist activation of arachidonate-regulated Ca2+-selective (ARC) channels in murine parotid and pancreatic acinar cells. J Physiol 2005; 564:791-801. [PMID: 15760932 PMCID: PMC1464460 DOI: 10.1113/jphysiol.2005.085704] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
ARC channels (arachidonate-regulated Ca(2+)-selective channels) are a novel type of highly Ca(2+)-selective channel that are specifically activated by low concentrations of agonist-induced arachidonic acid. This activation occurs in the absence of any depletion of internal Ca(2+) stores (i.e. they are 'non-capacitative'). Previous studies in HEK293 cells have shown that these channels provide the predominant pathway for the entry of Ca(2+) seen at low agonist concentrations where oscillatory [Ca(2+)](i) signals are typically produced. In contrast, activation of the more widely studied store-operated Ca(2+) channels (e.g. CRAC channels) is only seen at higher agonist concentrations where sustained 'plateau-type'[Ca(2+)](i) responses are observed. We have now demonstrated the presence of ARC channels in both parotid and pancreatic acinar cells and shown that, again, they are specifically activated by the low concentrations of appropriate agonists (carbachol in the parotid, and both carbachol and cholecystokinin in the pancreas) that are associated with oscillatory [Ca(2+)](i) signals in these cells. Uncoupling the receptor-mediated activation of cytosolic phospholipase A(2) (cPLA(2)) with isotetrandrine reduces the activation of the ARC channels by carbachol and, correspondingly, markedly inhibits the [Ca(2+)](i) signals induced by low carbachol concentrations, whilst those signals seen at high agonist concentrations are essentially unaffected. Interestingly, in the pancreatic acinar cells, activation by cholecystokinin induces a current through the ARC channels that is only approximately 60% of that seen with carbachol. This is consistent with previous reports indicating that carbachol-induced [Ca(2+)](i) signals in these cells are much more dependent on Ca(2+) entry than are the cholecystokinin-induced responses.
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Affiliation(s)
- Olivier Mignen
- Department of Pharmacology and Physiology, Box 711, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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