1
|
Xia K, Hei Z, Li S, Song H, Huang R, Ji X, Zhang F, Shen J, Zhang S, Peng S, Wu J. Berberine inhibits intracellular Ca 2+ signals in mouse pancreatic acinar cells through M 3 muscarinic receptors: Novel target, mechanism, and implication. Biochem Pharmacol 2024; 225:116279. [PMID: 38740221 DOI: 10.1016/j.bcp.2024.116279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/16/2024]
Abstract
Berberine, a natural isoquinoline alkaloid, exhibits a variety of pharmacological effects, but the pharmacological targets and mechanisms remain elusive. Here, we report a novel finding that berberine inhibits acetylcholine (ACh)-induced intracellular Ca2+ oscillations, mediated through an inhibition of the muscarinic subtype 3 (M3) receptor. Patch-clamp recordings and confocal Ca2+ imaging were applied to acute dissociated pancreatic acinar cells prepared from CD1 mice to examine the effects of berberine on ACh-induced Ca2+ oscillations. Whole-cell patch-clamp recordings showed that berberine (from 0.1 to 10 µM) reduced ACh-induced Ca2+ oscillations in a concentration-dependent manner, and this inhibition also depended on ACh concentrations. The inhibitory effect of berberine neither occurred in intracellular targets nor extracellular cholecystokinin (CCK) receptors, chloride (Cl-) channels, and store-operated Ca2+ channels. Together, the results demonstrate that berberine directly inhibits the muscarinic M3 receptors, further confirmed by evidence of the interaction between berberine and M3 receptors in pancreatic acinar cells.
Collapse
Affiliation(s)
- Kunkun Xia
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Department of Colorectal Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Zhijun Hei
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Department of Colorectal Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Shuangtao Li
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Huimin Song
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Rongni Huang
- 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
| | - Fenni Zhang
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Jianxin Shen
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Shuijun Zhang
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Shuang Peng
- School of Sport and Health Sciences, Guangzhou Sport University, Guangzhou 510000, China
| | - Jie Wu
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; 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, Phoenix 85013, USA
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Xia KK, Shen JX, Huang ZB, Song HM, Gao M, Chen DJ, Zhang SJ, Wu J. Heterogeneity of cannabinoid ligand-induced modulations in intracellular Ca 2+ signals of mouse pancreatic acinar cells in vitro. Acta Pharmacol Sin 2019; 40:410-417. [PMID: 30202013 PMCID: PMC6460482 DOI: 10.1038/s41401-018-0074-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 05/20/2018] [Indexed: 02/05/2023] Open
Abstract
We recently reported that a CB2R agonist, GW405833 (GW), reduced both the ACh-induced Ca2+ oscillations and the L-arginine-induced Ca2+ signal enhancement in mouse pancreatic acinar cells, suggesting that GW-induced inhibition may prevent the pathogenesis of acute pancreatitis. In this study, we aim to evaluate the effects of other cannabinoid ligands on Ca2+ signaling in acinar cells. Patch-clamp whole-cell recordings were applied to measure ACh-induced intracellular Ca2+ oscillations in pancreatic acinar cells acutely dissociated from wild-type (WT), CB1R knockout (KO), and CB2R KO mice, and the pharmacological effects of various cannabinoid ligands on the Ca2+ oscillations were examined. We found that all the 8 CB2R agonists tested inhibited ACh-induced Ca2+ oscillations. Among them, GW, JWH133, and GP1a caused potent inhibition with IC50 values of 5.0, 6.7, and 1.2 μmol/L, respectively. In CB2R KO mice or in the presence of a CB2R antagonist (AM630), the inhibitory effects of these 3 CB2R agonists were abolished, suggesting that they acted through the CB2Rs. The CB1R agonist ACEA also induced inhibition of Ca2+ oscillations that existed in CB1R KO mice and in the presence of a CB1R antagonist (AM251), suggesting a non-CB1R effect. In WT, CB1R KO, and CB2R KO mice, a nonselective CBR agonist, WIN55,212-2, inhibited Ca2+ oscillations, which was not mediated by CB1Rs or CB2Rs. The endogenous cannabinoid substance, 2-arachidonoylglycerol (2-AG), did not show an inhibitory effect on Ca2+ oscillations. In conclusion, CB2R agonists play critical roles in modulating Ca2+ signals in mouse pancreatic acinar cells, while other cannabinoid ligands modulate Ca2+ oscillations in a heterogeneous manner through a CB receptor or non-CB-receptor mechanism.
Collapse
Affiliation(s)
- Kun-Kun Xia
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 8501, USA
| | - Jian-Xin Shen
- Department of Physiology, Shantou University Medical College, Shantou, 515100, China
| | - Ze-Bing Huang
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 8501, USA
| | - Hui-Min Song
- Department of Physiology, Shantou University Medical College, Shantou, 515100, China
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 8501, USA
| | - De-Jie Chen
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 8501, USA
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China
| | - Shui-Jun Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jie Wu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 8501, USA.
- Department of Physiology, Shantou University Medical College, Shantou, 515100, China.
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
Collapse
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
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Martínez-Burgos MA, Granados MP, González A, Rosado JA, Yago MD, Salido GM, Martínez-Victoria E, Mañas M, Pariente JA. Involvement of ryanodine-operated channels in tert-butylhydroperoxide-evoked Ca2+ mobilisation in pancreatic acinar cells. ACTA ACUST UNITED AC 2006; 209:2156-64. [PMID: 16709917 DOI: 10.1242/jeb.02250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis, a disease characterised in its earliest stages by disruption of intracellular Ca2+ homeostasis. The present study was carried out in order to establish the effect of the organic pro-oxidant, tert-butylhydroperoxide (tBHP), on the mobilisation of intracellular Ca2+ stores in isolated rat pancreatic acinar cells and the mechanisms underlying this effect. Cytosolic free Ca2+ concentrations ([Ca2+]c) were monitored using a digital microspectrofluorimetric system in fura-2 loaded cells. In the presence of normal extracellular Ca2+ concentrations ([Ca2+]o), perfusion of pancreatic acinar cells with 1 mmol l-1 tBHP caused a slow sustained increase in [Ca2+]c. This increase was also observed in a nominally Ca2+-free medium, indicating a release of Ca2+ from intracellular stores. Pretreatment of cells with tBHP abolished the typical Ca2+ response of both the physiological agonist CCK-8 (1 nmol l-1) and thapsigargin (TPS, 1 micromol l-1), an inhibitor of the SERCA pump, in the absence of extracellular Ca2+. Similar results were observed with carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP, 0.5 micromol l-1), a mitochondrial uncoupler. In addition, depletion of either agonist-sensitive Ca2+ pools by CCK-8 or TPS or mitochondrial Ca2+ pools by FCCP were unable to prevent the tBHP-induced Ca2+ release. By contrast, simultaneous administration of TPS and FCCP clearly abolished the tBHP-induced Ca2+ release. These results show that tBHP releases Ca2+ from agonist-sensitive intracellular stores and from mitochondria. On the other hand, simultaneous application of FCCP and of 2-aminoethoxydiphenylborane (2-APB), a blocker of IP3-mediated Ca2+ release, was unable to suppress the increase in [Ca2+]c induced by tBHP, while the application of 50 micromol l-1 of ryanodine (which is able to block the ryanodine channels) inhibits tBHP-evoked Ca2+ mobilisation. These findings indicate that tBHP releases Ca2+ from non-mitochondrial Ca2+ pools through ryanodine channels.
Collapse
Affiliation(s)
- María A Martínez-Burgos
- Institute of Nutrition and Food Technology, Department of Physiology, University of Granada, C/Ramón y Cajal, 4. 18071, Granada, Spain.
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Camello-Almaraz C, Gomez-Pinilla PJ, Pozo MJ, Camello PJ. Mitochondrial reactive oxygen species and Ca2+ signaling. Am J Physiol Cell Physiol 2006; 291:C1082-8. [PMID: 16760264 DOI: 10.1152/ajpcell.00217.2006] [Citation(s) in RCA: 241] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria are an important source of reactive oxygen species (ROS) formed as a side product of oxidative phosphorylation. The main sites of oxidant production are complex I and complex III, where electrons flowing from reduced substrates are occasionally transferred to oxygen to form superoxide anion and derived products. These highly reactive compounds have a well-known role in pathological states and in some cellular responses. However, although their link with Ca(2+) is well studied in cell death, it has been hardly investigated in normal cytosolic calcium concentration ([Ca(2+)](i)) signals. Several Ca(2+) transport systems are modulated by oxidation. Oxidation increases the activity of inositol 1,4,5-trisphosphate and ryanodine receptors, the main channels releasing Ca(2+) from intracellular stores in response to cellular stimulation. On the other hand, mitochondria are known to control [Ca(2+)](i) signals by Ca(2+) uptake and release during cytosolic calcium mobilization, specially in mitochondria situated close to Ca(2+) release channels. Mitochondrial inhibitors modify calcium signals in numerous cell types, including oscillations evoked by physiological stimulus. Although these inhibitors reduce mitochondrial Ca(2+) uptake, they also impair ROS production in several systems. In keeping with this effect, recent reports show that antioxidants or oxidant scavengers also inhibit physiological calcium signals. Furthermore, there is evidence that mitochondria generate ROS in response to cell stimulation, an effect suppressed by mitochondrial inhibitors that simultaneously block [Ca(2+)](i) signals. Together, the data reviewed here indicate that Ca(2+)-mobilizing stimulus generates mitochondrial ROS, which, in turn, facilitate [Ca(2+)](i) signals, a new aspect in the biology of mitochondria. Finally, the potential implications for biological modeling are discussed.
Collapse
|
9
|
Camello-Almaraz MC, Pozo MJ, Murphy MP, Camello PJ. Mitochondrial production of oxidants is necessary for physiological calcium oscillations. J Cell Physiol 2005; 206:487-94. [PMID: 16206242 DOI: 10.1002/jcp.20498] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mitochondrial involvement in Ca2+ signaling is thought to be due to the effect of mitochondrial Ca2+ removal from and Ca2+ release to cytosolic domains close to ryanodine and IP3 Ca2+ channels. However, mitochondria are a source of low levels of endogenous reactive oxygen species, and Ca2+ release channels are known to be redox-sensitive. In the present work, we studied the role of mitochondrial production of oxygen species in Ca2+ oscillations during physiological stimulation. Mitochondria-targeted antioxidants and mitochondrial inhibitors quickly inhibited calcium oscillations in pancreatic acinar cells stimulated by postprandial levels of the gut hormone cholecystokinin. Confocal microscopy using different redox-sensitive dyes showed that cholecystokinin-induced oscillations are associated with mitochondrial production of reactive oxygen species. This production is inhibited by application of mitochondria-targeted antioxidants and mitochondrial inhibitors. In addition, we found no correlation between inhibition of oscillations and mitochondrial depolarization. We conclude that low level production of reactive oxygen species by mitochondria is a necessary element in the development of Ca2+ oscillations during physiological stimulation. This study unveils a new and unexplored aspect of the participation of mitochondria in calcium signals.
Collapse
|
10
|
Harks EGA, Scheenen WJJM, Peters PHJ, van Zoelen EJJ, Theuvenet APR. Prostaglandin F2 alpha induces unsynchronized intracellular calcium oscillations in monolayers of gap junctionally coupled NRK fibroblasts. Pflugers Arch 2003; 447:78-86. [PMID: 12851822 DOI: 10.1007/s00424-003-1126-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Accepted: 05/28/2003] [Indexed: 11/26/2022]
Abstract
We investigated the intracellular calcium oscillations induced by prostaglandin F2alpha (PGF2alpha) in individual cells of confluent, gap junction-coupled monolayers of normal rat kidney (NRK) fibroblasts. PGF2alpha (1000 nM) induced oscillations in more than 90% of the cells in the monolayer, but the frequency of these oscillations was highly variable between individual cells (0.2-1.4 min(-1)). The initial calcium peak resulted from calcium release from IP3-sensitive stores, while subsequent calcium transients were mediated by interplay between both IP3-sensitive calcium stores and calcium influx. The oscillation frequency was increased by sensitizing the IP3 receptor with thimerosal (10 microM) and depended on the extracellular calcium concentration. Thapsigargin (5 nM), which inhibits reuptake of calcium into the stores, only seemed to reduce the amplitude of the oscillation. Patch-clamp experiments revealed that PGF2alpha did not inhibit electrical coupling of the NRK cells in the monolayer. Gap junctional permeability of NRK cells thus appears to be sufficient to allow electrical coupling, resulting in a uniform membrane potential throughout the entire monolayer, but insufficient to synchronize the intracellular calcium oscillations upon PGF2alpha stimulation.
Collapse
Affiliation(s)
- Erik G A Harks
- Department of Cell Biology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | | | | | | | | |
Collapse
|
11
|
Schroeder KM, Wu J, Zhao L, Lukas RJ. Regulation by cycloheximide and lowered temperature of cell-surface alpha7-nicotinic acetylcholine receptor expression on transfected SH-EP1 cells. J Neurochem 2003; 85:581-91. [PMID: 12694384 DOI: 10.1046/j.1471-4159.2003.01658.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Heterologous expression of functional, nicotinic acetylcholine receptors (nAChR) in mammalian cells has been difficult to achieve or optimize, even for nAChR containing only one kind of subunit. In this study, we determined effects of lowered temperature or of exposure to the protein synthesis inhibitor cycloheximide (CHX) on cell surface expression of homomeric alpha7-nAChR in transfected SH-EP1 human epithelial cells. We found that incubation of cells for 2 days at 25 degrees C or in the presence of 0.5-2 microg/mL of CHX caused approximately four- or approximately eight-fold increases, respectively, in surface binding sites for 125I-labeled alpha-bungarotoxin (I-Bgt). These increases were accompanied by increases in peak whole-cell current responses to nicotinic agonists. Either treatment lowered protein synthesis and cell proliferation, but experiments using puromycin indicated that a reduction in protein synthesis or cell proliferation per se was not sufficient to increase surface binding. I-Bgt binding to whole-cell membrane pools increased in response to either treatment, suggesting that the increase in surface binding was due, at least in part, to an increase in intracellular receptor levels. The cyclophilin inhibitor cyclosporin A reduced surface expression in untreated as well as CHX- or 25 degrees C-treated cells. The results suggest practical means for increasing cell surface and functional expression of alpha7-nAChR. Although these effects are not simply due to protein synthesis inhibition or reduced cell proliferation, they do involve an increase in intracellular receptor pool size.
Collapse
Affiliation(s)
- Katherine M Schroeder
- Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013, USA
| | | | | | | |
Collapse
|
12
|
van Gorp RMA, Feijge MAH, Vuist WMJ, Rook MB, Heemskerk JWM. Irregular spiking in free calcium concentration in single, human platelets. Regulation by modulation of the inositol trisphosphate receptors. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1543-52. [PMID: 11874470 DOI: 10.1046/j.1432-1033.2002.02806.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fluorescence ratio imaging indicates that immobilized, aspirin-treated platelets, loaded with Fura-2, respond to inositol 1,4,5-trisphosphate- (InsP3)-generating agonists such as thrombin by high-frequency, irregular rises in cytosolic [Ca2+]i with spikes that vary in peak level and peak-to-peak interval. This differs from the regular [Ca2+]i oscillations observed in other, larger cells. We found that the thiol-reactive compounds thimerosal (10 microm) and U73122 (10 microm) evoked similar irregular Ca2+ responses in platelets, but in this case in the absence of InsP3 generation. Thrombin-induced spiking was acutely abolished by inhibiting phospholipase C or elevating intracellular cAMP levels, while spiking with sulfhydryl reagents was only partially blocked by cAMP elevation. Confocal laser scanning microscopy using fluo-3-loaded platelets indicated that, with all agonists or conditions, the irregular spikes were almost instantaneously raised in various regions within a single platelet. When using saponin-permeabilized platelets, we found that InsP3-induced Ca2+ release from stores was stimulated by modest Ca2+ concentrations, pointing to a mechanism of InsP3-dependent Ca2+-induced Ca2+ release (CICR). This process was completely inhibitable by heparin. The Ca2+ release by InsP3, but not the CICR sensor, was negatively regulated by cAMP elevation. Thimerosal treatment did not release Ca2+ from intracellular stores, but markedly potentiated the stimulatory effect of InsP3. In contrast, U73122 caused a heparin/cAMP-insensitive Ca2+ leak from stores that differed from those used by InsP3. Taken together, these results demonstrate that InsP3 receptor channels play a crucial role in the irregular, spiking Ca2+ signal of intact platelets, even when induced by agents such as thimerosal or U73122 which do not stimulate InsP3 formation. The irregular Ca2+ release events appear to be subjected to extensive regulation by: (a) InsP3 level, (b) the potentiating effect of elevated Ca2+ on InsP3 action via CICR, (c) InsP3 channel sensitization by sulfhydryl (thimerosal) modification, (d) InsP3 channel-independent Ca2+ leak with U73122, and (e) down-regulation via cAMP elevation. The observation that individual Ca2+ peaks were generated in various parts of a platelet at similar intervals and amplitudes points to effective cooperation of the various stores in the Ca2+-release process.
Collapse
|
13
|
Camello-Almaraz C, Salido GM, Pariente JA, Camello PJ. Role of mitochondria in Ca(2+) oscillations and shape of Ca(2+) signals in pancreatic acinar cells. Biochem Pharmacol 2002; 63:283-92. [PMID: 11841804 DOI: 10.1016/s0006-2952(01)00830-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We studied the role of mitochondria in Ca(2+) signals in fura-2 loaded exocrine pancreatic acinar cells. Mitochondrial depolarization in response to carbonylcyanide-p-tryfluoromethoxyphenyl hydrazone or rotenone (assessed by confocal microscopy using rhodamine-123) induced a partial but statistically significant reduction in the decay of Ca(2+) signals under different experimental conditions. Spreading of Ca(2+) waves evoked by the pancreatic secretagogue cholecystokinin cholecystokinin octapeptide was accelerated by mitochondrial inhibitors, whereas the cytosolic Ca(2+) concentration ([Ca(2+)](i)) oscillations in response to physiological levels of this hormone were suppressed by rotenone and carbonylcyanide-p-tryfluoromethoxyphenyl hydrazone. Oligomycin, an inhibitor of mitochondrial ATP synthase, did no affect either propagation of calcium waves nor [Ca(2+)](i) oscillations. Individual mitochondria of rhod-2 loaded acinar cells showed heterogeneous matrix Ca(2+) concentration increases in response to oscillatory and maximal levels of cholecystokinin octapeptide. On the other hand, using Ba(2+) for unequivocal study of capacitative calcium entry we found that mitochondrial inhibitors did not affect this process. Our results show that although the role of mitochondria as a Ca(2+) clearing system in exocrine cells is quantitatively secondary, they play an essential role in the spatial propagation of Ca(2+) waves and in the development of [Ca(2+)](i) oscillations.
Collapse
Affiliation(s)
- C Camello-Almaraz
- Department of Physiology, Faculty of Veterinary Sciences, University of Extremadura, 10071, Caceres, Spain
| | | | | | | |
Collapse
|
14
|
Wu J, Kamimura N, Takeo T, Suga S, Wakui M, Maruyama T, Mikoshiba K. 2-Aminoethoxydiphenyl borate modulates kinetics of intracellular Ca(2+) signals mediated by inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores in single pancreatic acinar cells of mouse. Mol Pharmacol 2000; 58:1368-74. [PMID: 11093775 DOI: 10.1124/mol.58.6.1368] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of the kinetics of intracellular Ca(2+) signals with a novel, membrane-penetrable, inositol 1,4,5-trisphosphate (InsP(3)) receptor/Ca(2+) channel modulator, 2-amino-ethoxydiphenyl borate (2APB), has been investigated using patch-clamp, whole-cell recording to monitor Ca(2+)-activated Cl(-) currents in single isolated pancreatic acinar cells. 2APB itself fails to evoke a detectable current response but it dramatically changes the kinetics of agonist-induced Ca(2+) release from pulsatile spikes to long-lasting, huge Ca(2+) waves, suggesting that 2APB coordinates local Ca(2+) release to generate global Ca(2+) signals. The regulation by 2APB can be elicited by internal perfusion of InsP(3) in a concentration-dependent manner, indicating that this regulation is not mediated through membrane receptors or G protein signal transduction. The InsP(3) receptor blocker heparin, but not the ryanodine-sensitive receptor blockers ruthenium red or ryanodine, abolishes 2APB-mediated regulation of Ca(2+) release. This results also suggest that 2APB effects are mediated through InsP(3) receptors. 2APB substantially modifies single inward Cl(-) current pulse evoked by the photolytic release of caged InsP(3) but not by caged Ca(2+). These data indicate that 2APB-induced regulation is mediated neither by Ca(2+)-induced Ca(2+) release nor by affecting Cl(-) channel activity directly. We conclude that 2APB regulates the kinetics of intracellular Ca(2+) signals, represented as the change in the Ca(2+) oscillation patterns from brief pulsatile spikes to huge, long-lasting Ca(2+) waves. Moreover, this regulation seems to be mediated through InsP(3)-sensitive Ca(2+) pools. 2APB may act as a novel, useful pharmacological tool to study the genesis of intracellular Ca(2+) signals.
Collapse
Affiliation(s)
- J Wu
- Department of Physiology, Hirosaki University School of Medicine, Hirosaki, Japan.
| | | | | | | | | | | | | |
Collapse
|
15
|
Camello C, Camello PJ, Pariente JA, Salido GM. Effects of antioxidants on calcium signal induced by cholecystokinin in mouse pancreatic acinar cells. J Physiol Biochem 2000; 56:173-80. [PMID: 11198153 DOI: 10.1007/bf03179784] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Digital imaging fluorescence microscopy was used to study the effect of two antioxidants, N-acetyl-cysteine (NAC) and glutathione, on the cytosolic free calcium concentration ([Ca2+]i) induced by cholecystokinin-octapeptide (CCK-8) of mouse pancreatic acinar cells. When acinar cells were preincubated with either NAC or glutathione, subsequent stimulation with CCK-8 in the presence of each antioxidant had no significant effect on the typical pattern of [Ca2+]i transient evoked by the gastrointestinal hormone. However, application of NAC to acinar cells pretreated for 60 min with the same antioxidant, strongly blocked the oscillatory pattern initiated by CCK-8, inhibiting both amplitude and frequency of calcium oscillations. By contrast, glutathione had no effect on the oscillatory pattern evoked by CCK-8. The present results allow us to speculate that during [Ca2+]i oscillation there is a production of oxidants that facilitate oscillations by enhancing release of calcium from internal stores.
Collapse
Affiliation(s)
- C Camello
- Department of Physiology, Faculty of Veterinary Sc, University of Extremadura, Cáceres, Spain
| | | | | | | |
Collapse
|
16
|
Mihai R, Lai T, Schofield G, Farndon JR. Thimerosal increases the responsiveness of the calcium receptor in human parathyroid and rMTC6-23 cells. Cell Calcium 1999; 26:95-101. [PMID: 10598273 DOI: 10.1054/ceca.1999.0055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Parathyroid cells express a plasma membrane calcium receptor (CaR), which is stimulated by a rise in extracellular calcium concentration ([Ca2+]ext). A decreased sensitivity to [Ca2+]ext occurs in adenomatous parathyroid cells in patients with primary hyperparathyroidism, but the underlying functional mechanism is not yet fully understood. This study explored whether CaR responsiveness is influenced by increasing the affinity of IP3 receptors--a major signalling component of other G-protein-coupled receptors. The sulphydryl reagent thimerosal was used to increase the responsiveness of IP3-receptors. Quantitative fluorescence microscopy in Fura-2-loaded cells was used to investigate the effects of thimerosal on the cytoplasmic calcium concentrations ([Ca2+]i) in human parathyroid cells and to compare its effects in a rat medullary thyroid carcinoma cell line (rMTC6-23) also expressing CaR. During incubation in Ca(2+)-free medium, thimerosal 5 microM induced a rapid sustained rise in [Ca2+]i in human parathyroid cells and no further [Ca2+]i increase appeared in response to the CaR agonist Gd3+ (100 microM). Thimerosal 1 microM induced only slow and minimal changes of basal [Ca2+]i and allowed a rapid response to Gd3+ 20 nM (a concentration without effect in control cells). The slope of the thimerosal-induced [Ca2+]i responses was steeper following exposure to CaR agonists. In the presence of 1 mM [Ca2+]ext, thimerosal (0.5 microM) induced a sharp increase in [Ca2+]i to a peak (within 60 s), followed either by return to basal [Ca2+]i or by a plateau of slightly higher amplitude. Similar results were obtained using rMTC6-23 cells. Thimerosal increases the responsiveness to CaR agonists through modulation of the sensitivity of the IP3 receptor in both parathyroid and rMTC6-23 cells.
Collapse
Affiliation(s)
- R Mihai
- Department of Surgery, Bristol Royal Infirmary, UK.
| | | | | | | |
Collapse
|
17
|
Wu J, Zeng YX, Hirokawa K. Signal pathway of mitogen-induced Ca2+-activated K+ currents in young and aged T-cell clones of C57BL/6 mice. Cell Signal 1999; 11:391-8. [PMID: 10400312 DOI: 10.1016/s0898-6568(99)00011-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Signal transduction pathways of mitogenic plant lectin, concanavalin A (Con A)- and ionomycin (INM)-induced (Ca2+-dependent K+ currents (I(Con A) and I(INM)) have been compared in young and aged T-cell clones by using the nystatin perforated patch-clamp whole-cell recording technique. In young T-cell clones, Con A evoked a long-lasting outward current which is mediated by the activation of the Ca2+-dependent K+ channels. The Ca2+ ionophore, INM, evoked a short-lasting Ca2+-dependent outward K+ current (I(INM)). The protein tyrosine kinase (PTK) inhibitor, herbimycin A (3 x 10(-6) M), but not the G protein blocker, pertussis toxin (PTX, 500 ng ml(-1)), completely prevented the I(Con A), but did not affect the I(INM). In aged T-cell clones, Con A fails to evoke any current response, while INM evokes an outward current which is comparable to that in a young T-cell clone. It is concluded that PTK, but not PTX-sensitive G proteins, plays a critical role in mediation of the signal transduction from Con A stimulation to activation of the Ca2+-dependent K+ channels, and that an impairment of the early signal pathway, perhaps the PTK, might be involved in the mechanism of the age-related decline of the proliferative response of T-lymphocytes to mitogenic stimulation.
Collapse
Affiliation(s)
- J Wu
- Department of Neurophysiology, Tohoku University School of Medicine, Sendai, Japan.
| | | | | |
Collapse
|