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Son GY, Zou A, Wahl A, Huang KT, Vinu M, Zorgit S, Zhou F, Wagner L, Idaghdour Y, Yule DI, Feske S, Lacruz RS. Loss of STIM1 and STIM2 in salivary glands disrupts ANO1 function but does not induce Sjogren's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574702. [PMID: 38260625 PMCID: PMC10802497 DOI: 10.1101/2024.01.08.574702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Sjogren's disease (SjD) is an autoimmune disease characterized by xerostomia (dry mouth), lymphocytic infiltration into salivary glands and the presence of SSA and SSB autoantibodies. Xerostomia is caused by hypofunction of the salivary glands and has been involved in the development of SjD. Saliva production is regulated by parasympathetic input into the glands initiating intracellular Ca 2+ signals that activate the store operated Ca 2+ entry (SOCE) pathway eliciting sustained Ca 2+ influx. SOCE is mediated by the STIM1 and STIM2 proteins and the ORAI1 Ca 2+ channel. However, there are no studies on the effects of lack of STIM1/2 function in salivary acini in animal models and its impact on SjD. Here we report that male and female mice lacking Stim1 and Stim2 ( Stim1/2 K14Cre ) in salivary glands showed reduced intracellular Ca 2+ levels via SOCE in parotid acini and hyposalivate upon pilocarpine stimulation. Bulk RNASeq of the parotid glands of Stim1/2 K14Cre mice showed a decrease in the expression of Stim1/2 but no other Ca 2+ associated genes mediating saliva fluid secretion. SOCE was however functionally required for the activation of the Ca 2+ activated chloride channel ANO1. Despite hyposalivation, ageing Stim1/2 K14Cre mice showed no evidence of lymphocytic infiltration in the glands or elevated levels of SSA or SSB autoantibodies in the serum, which may be linked to the downregulation of the toll-like receptor 8 ( Tlr8 ). By contrast, salivary gland biopsies of SjD patients showed increased STIM1 and TLR8 expression, and induction of SOCE in a salivary gland cell line increased the expression of TLR8 . Our data demonstrate that SOCE is an important activator of ANO1 function and saliva fluid secretion in salivary glands. They also provide a novel link between SOCE and TLR8 signaling which may explain why loss of SOCE does not result in SjD.
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Choi KJ, Hwang JW, Kim SH, Park HS. Ca 2+ entry through reverse Na+/Ca 2+ exchanger in NCI-H716, glucagon-like peptide-1 secreting cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY 2022; 26:219-225. [PMID: 35477549 PMCID: PMC9046890 DOI: 10.4196/kjpp.2022.26.3.219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/18/2022] [Accepted: 04/06/2022] [Indexed: 11/27/2022]
Abstract
Glucagon like peptide-1 (GLP-1) released from enteroendocine L-cells in the intestine has incretin effects due to its ability to amplify glucose-dependent insulin secretion. Promotion of an endogenous release of GLP-1 is one of therapeutic targets for type 2 diabetes mellitus. Although the secretion of GLP-1 in response to nutrient or neural stimuli can be triggered by cytosolic Ca2+ elevation, the stimulus-secretion pathway is not completely understood yet. Therefore, the aim of this study was to investigate the role of reverse Na+/Ca2+ exchanger (rNCX) in Ca2+ entry induced by muscarinic stimulation in NCI-H716 cells, a human enteroendocrine GLP-1 secreting cell line. Intracellular Ca2+ was repetitively oscillated by the perfusion of carbamylcholine (CCh), a muscarinic agonist. The oscillation of cytosolic Ca2+ was ceased by substituting extracellular Na+ with Li+ or NMG+. KB-R7943, a specific rNCX blocker, completely diminished CCh-induced cytosolic Ca2+ oscillation. Type 1 Na+/Ca2+ exchanger (NCX1) proteins were expressed in NCI-H716 cells. These results suggest that rNCX might play a crucial role in Ca2+ entry induced by cholinergic stimulation in NCI-H716 cells, a GLP-1 secreting cell line.
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Affiliation(s)
- Kyung Jin Choi
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Jin Wook Hwang
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Se Hoon Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Hyung Seo Park
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
- Myunggok Medical Research Institute, Konyang University, Daejeon 35365, Korea
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Costiniti V, Bomfim GH, Mitaishvili E, Son GY, Li Y, Lacruz RS. Calcium Transport in Specialized Dental Epithelia and Its Modulation by Fluoride. Front Endocrinol (Lausanne) 2021; 12:730913. [PMID: 34456880 PMCID: PMC8385142 DOI: 10.3389/fendo.2021.730913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Most cells use calcium (Ca2+) as a second messenger to convey signals that affect a multitude of biological processes. The ability of Ca2+ to bind to proteins to alter their charge and conformation is essential to achieve its signaling role. Cytosolic Ca2+ (cCa2+) concentration is maintained low at ~100 nM so that the impact of elevations in cCa2+ is readily sensed and transduced by cells. However, such elevations in cCa2+ must be transient to prevent detrimental effects. Cells have developed a variety of systems to rapidly clear the excess of cCa2+ including Ca2+ pumps, exchangers and sequestering Ca2+ within intracellular organelles. This Ca2+ signaling toolkit is evolutionarily adapted so that each cell, tissue, and organ can fulfill its biological function optimally. One of the most specialized cells in mammals are the enamel forming cells, the ameloblasts, which also handle large quantities of Ca2+. The end goal of ameloblasts is to synthesize, secrete and mineralize a unique proteinaceous matrix without the benefit of remodeling or repair mechanisms. Ca2+ uptake into ameloblasts is mainly regulated by the store operated Ca2+ entry (SOCE) before it is transported across the polarized ameloblasts to reach the insulated enamel space. Here we review the ameloblasts Ca2+ signaling toolkit and address how the common electronegative non-metal fluoride can alter its function, potentially addressing the biology of dental fluorosis.
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Affiliation(s)
| | | | | | | | | | - Rodrigo S. Lacruz
- Department Molecular Pathobiology, College of Dentistry, New York University, New York, NY, United States
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Takano T, Wahl AM, Huang KT, Narita T, Rugis J, Sneyd J, Yule DI. Highly localized intracellular Ca 2+ signals promote optimal salivary gland fluid secretion. eLife 2021; 10:66170. [PMID: 34240705 PMCID: PMC8352588 DOI: 10.7554/elife.66170] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 07/08/2021] [Indexed: 11/23/2022] Open
Abstract
Salivary fluid secretion involves an intricate choreography of membrane transporters to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are largely based on experimental observations in enzymatically isolated cells where the Ca2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels, present on the apical and basolateral plasma membrane, respectively. We monitored Ca2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca2+ transients that failed to fully propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. A new mathematical model, incorporating these data was constructed to probe how salivary secretion can be optimally stimulated by apical Ca2+ signals.
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Affiliation(s)
- Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Amanda M Wahl
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Kai-Ting Huang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
| | - Takanori Narita
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - John Rugis
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - James Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
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Kim MJ, Choi KJ, Yoon MN, Oh SH, Kim DK, Kim SH, Park HS. Hydrogen peroxide inhibits Ca 2+ efflux through plasma membrane Ca 2+-ATPase in mouse parotid acinar cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018. [PMID: 29520174 PMCID: PMC5840080 DOI: 10.4196/kjpp.2018.22.2.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intracellular Ca2+ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide (H2O2) on cytosolic Ca2+ accumulation in mouse parotid acinar cells. Intracellular Ca2+ levels were slowly elevated when 1 mM H2O2 was perfused in the presence of normal extracellular Ca2+. In a Ca2+-free medium, 1 mM H2O2 still enhanced the intracellular Ca2+ level. Ca2+ entry tested using manganese quenching technique was not affected by perfusion of 1 mM H2O2. On the other hand, 10 mM H2O2 induced more rapid Ca2+ accumulation and facilitated Ca2+ entry from extracellular fluid. Ca2+ refill into intracellular Ca2+ store and inositol 1,4,5-trisphosphate (1 µM)-induced Ca2+ release from Ca2+ store was not affected by 1 mM H2O2 in permeabilized cells. Ca2+ efflux through plasma membrane Ca2+-ATPase (PMCA) was markedly blocked by 1 mM H2O2 in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected H2O2-induced Ca2+ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of H2O2 under pathological conditions may lead to cytosolic Ca2+ accumulation and that the primary mechanism of H2O2-induced Ca2+ accumulation is likely to inhibit Ca2+ efflux through PMCA rather than mobilize Ca2+ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.
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Affiliation(s)
- Min Jae Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Kyung Jin Choi
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Mi Na Yoon
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Sang Hwan Oh
- Department of Dental Hygiene, College of Medical Science, Konyang University, Daejeon 35365, Korea
| | - Dong Kwan Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Se Hoon Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Hyung Seo Park
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea.,Myunggok Medical Research Institute, Konyang University, Daejeon 35365, Korea
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Yoon MN, Kim MJ, Koong HS, Kim DK, Kim SH, Park HS. Ethanol suppresses carbamylcholine-induced intracellular calcium oscillation in mouse pancreatic acinar cells. Alcohol 2017; 63:53-59. [PMID: 28847382 DOI: 10.1016/j.alcohol.2017.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/23/2017] [Accepted: 03/23/2017] [Indexed: 12/31/2022]
Abstract
Oscillation of intracellular calcium levels is closely linked to initiating secretion of digestive enzymes from pancreatic acinar cells. Excessive alcohol consumption is known to relate to a variety of disorders in the digestive system, including the exocrine pancreas. In this study, we have investigated the role and mechanism of ethanol on carbamylcholine (CCh)-induced intracellular calcium oscillation in murine pancreatic acinar cells. Ethanol at concentrations of 30 and 100 mM reversibly suppressed CCh-induced Ca2+ oscillation in a dose-dependent manner. Pretreatment of ethanol has no effect on the store-operated calcium entry induced by 10 μM of CCh. Ethanol significantly reduced the initial calcium peak induced by low concentrations of CCh and therefore, the CCh-induced dose-response curve of the initial calcium peak was shifted to the right by ethanol pretreatment. Furthermore, ethanol significantly dose-dependently reduced inositol 1,4,5-trisphosphate-induced calcium release from the internal stores in permeabilized acinar cells. These results provide evidence that excessive alcohol intake could impair cytosolic calcium oscillation through inhibiting calcium release from intracellular stores in mouse pancreatic acinar cells.
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Affiliation(s)
- Mi Na Yoon
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea
| | - Min Jae Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea
| | - Hwa Soo Koong
- Department of Dental Hygiene, College of Medical Science, Konyang University, Daejeon 35365, Republic of Korea
| | - Dong Kwan Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea
| | - Se Hoon Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea
| | - Hyung Seo Park
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; Myunggok Medical Research Institute, Konyang University, Daejeon 35365, Republic of Korea.
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Wang L, Wagner LE, Alzayady KJ, Yule DI. Region-specific proteolysis differentially regulates type 1 inositol 1,4,5-trisphosphate receptor activity. J Biol Chem 2017; 292:11714-11726. [PMID: 28526746 DOI: 10.1074/jbc.m117.789917] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/11/2017] [Indexed: 12/31/2022] Open
Abstract
The inositol 1,4,5 trisphosphate receptor (IP3R) is an intracellular Ca2+ release channel expressed predominately on the membranes of the endoplasmic reticulum. IP3R1 can be cleaved by caspase or calpain into at least two receptor fragments. However, the functional consequences of receptor fragmentation are poorly understood. Our previous work has demonstrated that IP3R1 channels, formed following either enzymatic fragmentation or expression of the corresponding complementary polypeptide chains, retain tetrameric architecture and are still activated by IP3 binding despite the loss of peptide continuity. In this study, we demonstrate that region-specific receptor fragmentation modifies channel regulation. Specifically, the agonist-evoked temporal Ca2+ release profile and protein kinase A modulation of Ca2+ release are markedly altered. Moreover, we also demonstrate that activation of fragmented IP3R1 can result in a distinct functional outcome. Our work suggests that proteolysis of IP3R1 may represent a novel form of modulation of IP3R1 channel function and increases the repertoire of Ca2+ signals achievable through this channel.
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Affiliation(s)
- Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Larry E Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Kamil J Alzayady
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642.
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Yoon MN, Kim DK, Kim SH, Park HS. Hydrogen peroxide attenuates refilling of intracellular calcium store in mouse pancreatic acinar cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:233-239. [PMID: 28280417 PMCID: PMC5343057 DOI: 10.4196/kjpp.2017.21.2.233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 01/05/2023]
Abstract
Intracellular calcium (Ca2+) oscillation is an initial event in digestive enzyme secretion of pancreatic acinar cells. Reactive oxygen species are known to be associated with a variety of oxidative stress-induced cellular disorders including pancreatitis. In this study, we investigated the effect of hydrogen peroxide (H2O2) on intracellular Ca2+ accumulation in mouse pancreatic acinar cells. Perfusion of H2O2 at 300 µM resulted in additional elevation of intracellular Ca2+ levels and termination of oscillatory Ca2+ signals induced by carbamylcholine (CCh) in the presence of normal extracellular Ca2+. Antioxidants, catalase or DTT, completely prevented H2O2-induced additional Ca2+ increase and termination of Ca2+ oscillation. In Ca2+-free medium, H2O2 still enhanced CCh-induced intracellular Ca2+ levels and thapsigargin (TG) mimicked H2O2-induced cytosolic Ca2+ increase. Furthermore, H2O2-induced elevation of intracellular Ca2+ levels was abolished under sarco/endoplasmic reticulum Ca2+ ATPase-inactivated condition by TG pretreatment with CCh. H2O2 at 300 µM failed to affect store-operated Ca2+ entry or Ca2+ extrusion through plasma membrane. Additionally, ruthenium red, a mitochondrial Ca2+ uniporter blocker, failed to attenuate H2O2-induced intracellular Ca2+ elevation. These results provide evidence that excessive generation of H2O2 in pathological conditions could accumulate intracellular Ca2+ by attenuating refilling of internal Ca2+ stores rather than by inhibiting Ca2+ extrusion to extracellular fluid or enhancing Ca2+ mobilization from extracellular medium in mouse pancreatic acinar cells.
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Affiliation(s)
- Mi Na Yoon
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Dong Kwan Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Se Hoon Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea
| | - Hyung Seo Park
- Department of Physiology, College of Medicine, Konyang University, Daejeon 35365, Korea.; Myunggok Medical Research Institute, Konyang University, Daejeon 35365, Korea
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Fujii N, Halili L, Singh MS, Meade RD, Kenny GP. Intradermal administration of ATP augments methacholine-induced cutaneous vasodilation but not sweating in young males and females. Am J Physiol Regul Integr Comp Physiol 2015; 309:R912-9. [PMID: 26290105 DOI: 10.1152/ajpregu.00261.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/10/2015] [Indexed: 12/14/2022]
Abstract
Acetylcholine released from cholinergic nerves is a key neurotransmitter contributing to heat stress-induced cutaneous vasodilation and sweating. Given that sympathetic cholinergic nerves also release ATP, ATP may play an important role in modulating cholinergic cutaneous vasodilation and sweating. However, the pattern of response may differ between males and females given reports of sex-related differences in the peripheral mechanisms governing these heat loss responses. Cutaneous vascular conductance (CVC, laser-Doppler perfusion units/mean arterial pressure) and sweat rate (ventilated capsule) were evaluated in 17 young adults (8 males, 9 females) at four intradermal microdialysis skin sites continuously perfused with: 1) lactated Ringer (Control), 2) 0.3 mM ATP, 3) 3 mM ATP, or 4) 30 mM ATP. At all skin sites, methacholine was coadministered in a concentration-dependent manner (0.0125, 0.25, 5, 100, 2,000 mM, each for 25 min). In both males and females, CVC was elevated with the lone infusion of 30 mM ATP (both P < 0.05), but not with 0.3 and 3 mM ATP compared with control (all P >0.27). However, 0.3 mM ATP induced a greater increase in CVC compared with control in response to 100 mM methacholine infusion in males (P < 0.05). In females, 0.3 mM ATP infusion resulted in a lower concentration of methacholine required to elicit a half-maximal response (EC50) (P < 0.05). In both males and females, methacholine-induced sweating was unaffected by any concentration of ATP (all P > 0.44). We demonstrate that ATP enhances cholinergic cutaneous vasodilation albeit the pattern of response differs between males and females. Furthermore, we show that ATP does not modulate cholinergic sweating.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Lyra Halili
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Maya Sarah Singh
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Vervloessem T, Yule DI, Bultynck G, Parys JB. The type 2 inositol 1,4,5-trisphosphate receptor, emerging functions for an intriguing Ca²⁺-release channel. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1992-2005. [PMID: 25499268 DOI: 10.1016/j.bbamcr.2014.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/19/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) type 2 (IP3R2) is an intracellular Ca²⁺-release channel located on the endoplasmic reticulum (ER). IP3R2 is characterized by a high sensitivity to both IP3 and ATP and is biphasically regulated by Ca²⁺. Furthermore, IP3R2 is modulated by various protein kinases. In addition to its regulation by protein kinase A, IP3R2 forms a complex with adenylate cyclase 6 and is directly regulated by cAMP. Finally, in the ER, IP3R2 is less mobile than the other IP3R isoforms, while its functional properties appear dominant in heterotetramers. These properties make the IP3R2 a Ca²⁺ channel with exquisite properties for setting up intracellular Ca²⁺ signals with unique characteristics. IP3R2 plays a crucial role in the function of secretory cell types (e.g. pancreatic acinar cells, hepatocytes, salivary gland, eccrine sweat gland). In cardiac myocytes, the role of IP3R2 appears more complex, because, together with IP3R1, it is needed for normal cardiogenesis, while its aberrant activity is implicated in cardiac hypertrophy and arrhythmias. Most importantly, its high sensitivity to IP3 makes IP3R2 a target for anti-apoptotic proteins (e.g. Bcl-2) in B-cell cancers. Disrupting IP3R/Bcl-2 interaction therefore leads in those cells to increased Ca²⁺ release and apoptosis. Intriguingly, IP3R2 is not only implicated in apoptosis but also in the induction of senescence, another tumour-suppressive mechanism. These results were the first to unravel the physiological and pathophysiological role of IP3R2 and we anticipate that further progress will soon be made in understanding the function of IP3R2 in various tissues and organs.
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Affiliation(s)
- Tamara Vervloessem
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - David I Yule
- University of Rochester, Department of Pharmacology and Physiology, Rochester, NY, USA
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium.
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Burnstock G. Purinergic signalling in the gastrointestinal tract and related organs in health and disease. Purinergic Signal 2014; 10:3-50. [PMID: 24307520 PMCID: PMC3944042 DOI: 10.1007/s11302-013-9397-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/04/2023] Open
Abstract
Purinergic signalling plays major roles in the physiology and pathophysiology of digestive organs. Adenosine 5'-triphosphate (ATP), together with nitric oxide and vasoactive intestinal peptide, is a cotransmitter in non-adrenergic, non-cholinergic inhibitory neuromuscular transmission. P2X and P2Y receptors are widely expressed in myenteric and submucous enteric plexuses and participate in sympathetic transmission and neuromodulation involved in enteric reflex activities, as well as influencing gastric and intestinal epithelial secretion and vascular activities. Involvement of purinergic signalling has been identified in a variety of diseases, including inflammatory bowel disease, ischaemia, diabetes and cancer. Purinergic mechanosensory transduction forms the basis of enteric nociception, where ATP released from mucosal epithelial cells by distension activates nociceptive subepithelial primary afferent sensory fibres expressing P2X3 receptors to send messages to the pain centres in the central nervous system via interneurons in the spinal cord. Purinergic signalling is also involved in salivary gland and bile duct secretion.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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