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Kim MH, Seo JB, Burnett LA, Hille B, Koh DS. Characterization of store-operated Ca2+ channels in pancreatic duct epithelia. Cell Calcium 2013; 54:266-75. [PMID: 23968882 PMCID: PMC3809127 DOI: 10.1016/j.ceca.2013.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 07/18/2013] [Accepted: 07/20/2013] [Indexed: 11/30/2022]
Abstract
Store-operated Ca2+ channels (SOCs) are activated by depletion of intracellular Ca2+ stores following agonist-mediated Ca2+ release. Previously we demonstrated that Ca2+ influx through SOCs elicits exocytosis efficiently in pancreatic duct epithelial cells (PDEC). Here we describe the biophysical, pharmacological, and molecular properties of the duct epithelial SOCs using Ca2+ imaging, whole-cell patch-clamp, and molecular biology. In PDEC, agonists of purinergic, muscarinic, and adrenergic receptors coupled to phospholipase C activated SOC-mediated Ca2+ influx as Ca2+ was released from intracellular stores. Direct measurement of [Ca2+] in the ER showed that SOCs greatly slowed depletion of the ER. Using IP3 or thapsigargin in the patch pipette elicited inwardly rectifying SOC currents. The currents increased ∼8-fold after removal of extracellular divalent cations, suggesting competitive permeation between mono- and divalent cations. The current was completely blocked by high doses of La3+ and 2-aminoethoxydiphenyl borate (2-APB) but only partially depressed by SKF-96365. In polarized PDEC, SOCs were localized specifically to the basolateral membrane. RT-PCR screening revealed the expression of both STIM and Orai proteins for the formation of SOCs in PDEC. By expression of fluorescent STIM1 and Orai1 proteins in PDEC, we confirmed that colocalization of the two proteins increases after store depletion. In conclusion, basolateral Ca2+ entry through SOCs fills internal Ca2+ stores depleted by external stimuli and will facilitate cellular processes dependent on cytoplasmic Ca2+ such as salt and mucin secretion from the exocrine pancreatic ducts.
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Affiliation(s)
- Mean-Hwan Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jong Bae Seo
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, USA
| | - Lindsey A. Burnett
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, USA
| | - Bertil Hille
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, USA
| | - Duk-Su Koh
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, USA
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2
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Buyck JM, Verriere V, Benmahdi R, Higgins G, Guery B, Matran R, Harvey BJ, Faure K, Urbach V. P. aeruginosa LPS stimulates calcium signaling and chloride secretion via CFTR in human bronchial epithelial cells. J Cyst Fibros 2012; 12:60-7. [PMID: 22809761 DOI: 10.1016/j.jcf.2012.06.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 06/06/2012] [Accepted: 06/14/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa airway infection is associated with a high mortality rate in cystic fibrosis. Lipopolysaccharide (LPS), a main constituent of the outer membrane of P. aeruginosa, is responsible for activation of innate immune response but its role on airway epithelium ion transport, is not well known. The aim of this study was to determine the role for P. aeruginosa LPS in modulating chloride secretion and intracellular calcium in the human bronchial epithelial cell line, 16HBE14o-. METHODS We used intracellular calcium imaging and short-circuit current measurement upon exposure of cells to P. aeruginosa LPS. RESULTS Apical LPS stimulated intracellular calcium release and calcium entry and enhanced chloride secretion. This latter effect was significantly inhibited by CFTR(inh)-172 and BAPTA-AM (intracellular Ca(2+) chelator). CONCLUSIONS Our data provides evidence for a new role of P. aeruginosa LPS in stimulating calcium entry and release and a subsequent chloride secretion via CFTR in human bronchial epithelium.
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Affiliation(s)
- J M Buyck
- Laboratoire de Physiologie, EA2689, IMPRT IFR 114, Université de Lille, Lille cedex, France.
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3
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Dong X, Smoll EJ, Ko KH, Lee J, Chow JY, Kim HD, Insel PA, Dong H. P2Y receptors mediate Ca2+ signaling in duodenocytes and contribute to duodenal mucosal bicarbonate secretion. Am J Physiol Gastrointest Liver Physiol 2009; 296:G424-32. [PMID: 19074643 PMCID: PMC2643905 DOI: 10.1152/ajpgi.90314.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Since little is known about the role of P2Y receptors (purinoceptors) in duodenal mucosal bicarbonate secretion (DMBS), we sought to investigate the expression and function of these receptors in duodenal epithelium. Expression of P2Y(2) receptors was detected by RT-PCR in mouse duodenal epithelium and SCBN cells, a duodenal epithelial cell line. UTP, a P2Y(2)-receptor agonist, but not ADP (10 microM), significantly induced murine duodenal short-circuit current and DMBS in vitro; these responses were abolished by suramin (300 microM), a P2Y-receptor antagonist, or 2-aminoethoxydiphenyl borate (2-APB; 100 microM), a store-operated channel blocker. Mucosal or serosal addition of UTP induced a comparable DMBS in wild-type mice, but markedly impaired response occurred in P2Y(2) knockout mice. Acid-stimulated DMBS in vivo was significantly inhibited by suramin (1 mM) or PPADS (30 microM). Both ATP and UTP, but not ADP (1 microM), raised cytoplasmic-free Ca(2+) concentrations ([Ca(2+)](cyt)) with similar potencies in SCBN cells. ATP-induced [Ca(2+)](cyt) was attenuated by U-73122 (10 microM), La(3+) (30 microM), or 2-APB (10 microM), but was not significantly affected by nifedipine (10 microM). UTP (1 microM) induced a [Ca(2+)](cyt) transient in Ca(2+)-free solutions, and restoration of external Ca(2+) (2 mM) raised [Ca(2+)](cyt) due to capacitative Ca(2+) entry. La(3+) (30 microM), SK&F96365 (30 microM), and 2-APB (10 microM) inhibited UTP-induced Ca(2+) entry by 92, 87, and 94%, respectively. Taken together, our results imply that activation of P2Y(2) receptors enhances DMBS via elevation of [Ca(2+)](cyt) that likely results from an initial increase in intracellular Ca(2+) release followed by extracellular Ca(2+) entry via store-operated channel.
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Affiliation(s)
- Xiao Dong
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Eric James Smoll
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Kwang Hyun Ko
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Jonathan Lee
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Jimmy Yip Chow
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Ho Dong Kim
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Paul A. Insel
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
| | - Hui Dong
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California
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4
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Ando S, Otani H, Yagi Y, Kawai K, Araki H, Nakamura T, Fukuhara S, Inagaki C. Protease-activated receptor 4-mediated Ca2+ signaling in mouse lung alveolar epithelial cells. Life Sci 2007; 81:794-802. [PMID: 17707436 DOI: 10.1016/j.lfs.2007.06.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 06/08/2007] [Accepted: 06/19/2007] [Indexed: 11/30/2022]
Abstract
Protease-activated receptor (PAR)-4 is a recently identified low-affinity thrombin receptor that plays a pathophysiological role in many types of tissues including the lung. Here, we showed for the first time that PAR4 mRNA and protein are expressed on primary cultured mouse lung alveolar epithelial cells by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemical analyses. In a fura 2-AM-loaded single epithelial cell, stimulation with thrombin (1 U/ml) and a PAR4 agonist peptide (AYPGKF-NH(2), 1-100 microM) increased intracellular Ca(2+) concentration ([Ca(2+)](i)), which consisted of an initial peak phase followed by a slowly decaying delayed phase, while a PAR1 agonist peptide, TFLLR-NH(2) (1-100 microM), induced a transient increase in [Ca(2+)](i). AYPGKF-NH(2) (10 microM)-induced [Ca(2+)](i) response was attenuated by a PAR4 antagonist peptide (tcY-NH(2)), a phospholipase C inhibitor, U-73122 (1-10 microM) or a Ca(2+)-ATPase inhibitor, thapsigargin (1 microM). Removal of extracellular Ca(2+) or an inhibitor of store-operated Ca(2+) entry, trans-resveratrol (1 microM) shortened the time to shut off the Ca(2+) response without any significant effects on the magnitude of the peak [Ca(2+)](i). Thus, stimulation of PAR4 appeared to mobilize Ca(2+) from intracellular stores in the initial peak response and to enhance Ca(2+) entry through the store depletion-operated pathway in the delayed phase. The latter mechanism probably contributed to the longer responsiveness of PAR4 stimulation.
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MESH Headings
- Animals
- Calcium/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Cells, Cultured
- Dose-Response Relationship, Drug
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Epithelial Cells/pathology
- Estrenes/pharmacology
- Gene Expression/drug effects
- Mice
- Mice, Inbred C57BL
- Oligopeptides/pharmacology
- Pulmonary Alveoli/drug effects
- Pulmonary Alveoli/metabolism
- Pulmonary Alveoli/pathology
- Pyrrolidinones/pharmacology
- RNA, Messenger/metabolism
- Receptor, PAR-1/agonists
- Receptor, PAR-1/genetics
- Receptor, PAR-1/metabolism
- Receptors, Thrombin/agonists
- Receptors, Thrombin/genetics
- Receptors, Thrombin/metabolism
- Resveratrol
- Stilbenes/pharmacology
- Thapsigargin/pharmacology
- Thrombin/pharmacology
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Affiliation(s)
- Seijitsu Ando
- Department of Pharmacology, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
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5
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Roberts VHJ, Waters LH, Powell T. Purinergic receptor expression and activation in first trimester and term human placenta. Placenta 2006; 28:339-47. [PMID: 16764923 DOI: 10.1016/j.placenta.2006.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 04/20/2006] [Accepted: 04/24/2006] [Indexed: 11/25/2022]
Abstract
Intracellular calcium concentration ([Ca(2+)](i)) is an important signalling molecule in the human placenta and regulation of [Ca(2+)](i) must be tightly controlled to ensure normal cell function and in order to meet the changing demand for calcium with increased fetal growth over gestation. Little is known about the receptors and mechanisms involved in intracellular calcium signalling in the human placenta but in isolated cytotrophoblast cells members of the P2 purinergic receptor family have been shown to mediate an ATP-stimulated rise in [Ca(2+)](i). In this study we examined activation and expression of several of the purinergic receptor subtypes in human placental villous fragments at two stages of gestation, first trimester and term. We demonstrate mRNA and protein expression of the P2X(4), P2X(7) and P2Y(2) subtypes but found no evidence of P2Y(4) protein in the placenta. Using fluorescent calcium imaging we demonstrate that 300 microM ATP, 450 microM UTP and 300 microM BzATP significantly elevate [Ca(2+)](i) in villous fragments with a significant increase in agonist-induced response seen in the term compared to the first trimester fragments (ATP, P<0.0001; UTP, P=0.018; BzATP, P=0.015). The roles of the purinergic receptors within the human placenta are not known but it seems likely for this study that calcium handling through these receptors is altered with advancing gestation. This may be due to the need to meet increased fetal Ca(2+) requirements due to growth or as a secondary function to alterations in placental [Ca(2+)](i) signalling.
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Affiliation(s)
- V H J Roberts
- Division of Human Development, St Mary's Hospital, University of Manchester, Manchester M13 0JH, UK.
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6
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Caroppo R, Gerbino A, Fistetto G, Colella M, Debellis L, Hofer AM, Curci S. Extracellular calcium acts as a "third messenger" to regulate enzyme and alkaline secretion. ACTA ACUST UNITED AC 2004; 166:111-9. [PMID: 15240573 PMCID: PMC2172151 DOI: 10.1083/jcb.200310145] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It is generally assumed that the functional consequences of stimulation with Ca2+-mobilizing agonists are derived exclusively from the second messenger action of intracellular Ca2+, acting on targets inside the cells. However, during Ca2+ signaling events, Ca2+ moves in and out of the cell, causing changes not only in intracellular Ca2+, but also in local extracellular Ca2+. The fact that numerous cell types possess an extracellular Ca2+ “sensor” raises the question of whether these dynamic changes in external [Ca2+] may serve some sort of messenger function. We found that in intact gastric mucosa, the changes in extracellular [Ca2+] secondary to carbachol-induced increases in intracellular [Ca2+] were sufficient and necessary to elicit alkaline secretion and pepsinogen secretion, independent of intracellular [Ca2+] changes. These findings suggest that extracellular Ca2+ can act as a “third messenger” via Ca2+ sensor(s) to regulate specific subsets of tissue function previously assumed to be under the direct control of intracellular Ca2+.
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Affiliation(s)
- Rosa Caroppo
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Italy
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7
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Bahra P, Mesher J, Li S, Poll CT, Danahay H. P2Y2-receptor-mediated activation of a contralateral, lanthanide-sensitive calcium entry pathway in the human airway epithelium. Br J Pharmacol 2004; 143:91-8. [PMID: 15289296 PMCID: PMC1575274 DOI: 10.1038/sj.bjp.0705913] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Receptor-mediated calcium entry (RMCE) was examined in well-differentiated cultures of normal human bronchial epithelial cells (HBECs). Changes in intracellular free Ca(2+) ([Ca(2+)](i)) were quantified using fluorescence ratio imaging of Fura-2-loaded cells during perfusion with Ca(2+) mobilizing agonists. 2. Initial studies revealed an agonist potency of ATP=uridine triphosphate (UTP) >ADP=uridine diphosphate, consistent with purinergic activation of an apical P2Y(2)-receptor mediating the increase in [Ca(2+)](i) in HBECs. 3. Apical UTP (30 microm) induced a sustained period of elevated [Ca(2+)](i) between 300 and 600 s following agonist stimulation that extracellular Ca(2+) free studies indicated was dominated by Ca(2+) influx. 4. RMCE was inhibited by 100 nm La(3+) (83+/-3%) or Gd(3+) (95+/-7%) (P<0.005, n=4-11) and was partially attenuated by Ni(2+) (1 mm) (58.7+/-5.0%, P<0.005, n=9). 5. RMCE was also partially sensitive (< 25% inhibition, P<0.01) to the cation channel blockers SKF96365 (30 microm) and econazole (30 microm), but was insensitive to both verapamil (1 microm) and ruthenium red (10 microm). 6. Using either a sided Ca(2+) readdition protocol or unilateral La(3+), established that the RMCE pathway was located exclusively on the basolateral membrane. 7. The pharmacological sensitivity of the P2Y(2)-receptor activated Ca(2+) entry pathway in the human airway epithelium is inconsistent with the established profile of TRP channel families and is therefore likely to be of an as-yet uncharacterized molecular identity.
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Affiliation(s)
- Parmjit Bahra
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex
| | - Jonathan Mesher
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex
| | - Su Li
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex
| | - Christopher T Poll
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex
| | - Henry Danahay
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex
- Author for correspondence:
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8
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Szkotak AJ, Man SFP, Duszyk M. The role of the basolateral outwardly rectifying chloride channel in human airway epithelial anion secretion. Am J Respir Cell Mol Biol 2003; 29:710-20. [PMID: 12777250 DOI: 10.1165/rcmb.2003-0109oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The purpose of this study was to characterize basolateral anion channels in Calu-3 and normal human bronchial epithelial cells, and their role in anion secretion. Patch clamp studies identified an outwardly rectifying Cl- channel (ORCC), which could be activated by the adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine (NECA). Short-circuit current measurements revealed that NECA activates a basolateral, but not an apical, anion conductance sensitive to 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid, and to 9-anthracenecarboxylic acid, but not to 4,4'-dinitrostilbene-2,2'-disulfonic acid. Apical membrane permeabilization studies confirmed the presence of basolateral anion channels, established their halide permeability sequence (Cl- >/= Br- >> I-), and demonstrated their outwardly rectifying nature. Experiments using H-89, forskolin, and Ht31 demonstrated that adenosine receptor dependent activation of basolateral ORCC was cAMP- and potentially A-kinase anchoring protein-dependent. Neither BAPTA-AM treatment nor basolateral Ca2+ removal had any effect on the activation of these channels. Anion replacement and 36Cl- flux studies show that Calu-3 cells primarily secrete HCO3- when stimulated with NECA, and that Cl- secretion can be stimulated by blocking basolateral ORCC, whereas normal human bronchial epithelial cells exclusively secrete Cl- under all conditions studied. We propose a novel model of anion secretion in which ORCC recycles Cl- across the basolateral membrane, allowing preferential HCO3- secretion.
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Affiliation(s)
- Artur J Szkotak
- Department of Physiology, University of Alberta, 7-46 Medical Sciences Bldg., Edmonton, Alberta, T6G 2H7 Canada
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9
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Li S, Westwick J, Poll C. Transient receptor potential (TRP) channels as potential drug targets in respiratory disease. Cell Calcium 2003; 33:551-8. [PMID: 12765700 DOI: 10.1016/s0143-4160(03)00060-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Calcium-permeable channels have traditionally been thought of as therapeutic targets in excitable cells. For instance, voltage-operated Ca2+ channels in neurones and smooth muscle cells for neurological and cardiovascular diseases although calcium-permeable channels are also functionally important in electrically non-excitable cells. In the lung, calcium channels play a pivotal role in the activation of all the cell types present, whether resident cells such as airway smooth muscle cells and macrophages or migratory cells such as neutrophils or lymphocytes.Previously, research in this area has been hindered by the lack of obvious molecular identity. More recently, the emergence of the transient receptor potential (TRP) cation family has yielded promising candidates which may underpin the different receptor-operated calcium influx pathways. The challenge now, is to ascribe function to the TRP channels expressed in each cell type as a first step in identifying which TRP channels may be potential drug targets for asthma and chronic obstructive pulmonary disease (COPD) (Fig. 1).
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Affiliation(s)
- Su Li
- Novartis Respiratory Research Centre, Wimblehurst Road, Horsham, West Sussex RH12 5AB, UK.
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10
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Song JC, Rangachari PK, Matthews JB. Opposing effects of PKCalpha and PKCepsilon on basolateral membrane dynamics in intestinal epithelia. Am J Physiol Cell Physiol 2002; 283:C1548-56. [PMID: 12372816 DOI: 10.1152/ajpcell.00105.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PKC is a critical effector of plasma membrane dynamics, yet the mechanism and isoform-specific role of PKC are poorly understood. We recently showed that the phorbol ester PMA (100 nM) induces prompt activation of the novel isoform PKCepsilon followed by late activation of the conventional isoform PKCalpha in T84 intestinal epithelia. PMA also elicited biphasic effects on endocytosis, characterized by an initial stimulatory phase followed by an inhibitory phase. Activation of PKCepsilon was shown to be responsible for stimulation of basolateral endocytosis, but the role of PKCalpha was not defined. Here, we used detailed time-course analysis as well as selective activators and inhibitors of PKC isoforms to infer the action of PKCalpha on basolateral endocytosis. Inhibition of PKC by the selective conventional PKC inhibitor Gö-6976 (5 microM) completely blocked the late inhibitory phase and markedly prolonged the stimulatory phase of endocytosis measured by FITC-dextran uptake. The PKCepsilon-selective agonist carbachol (100 microM) induced prolonged stimulation of endocytosis devoid of an inhibitory phase. Actin disassembly caused by PMA was completely blocked by Gö-6850 but not by Gö-6976, implicating PKCepsilon as the key isoform responsible for actin disruption. The Ca2+ agonist thapsigargin (5 microM) induced early activation of PKC when added simultaneously with PMA. This early activation of PKCalpha blocked the ability of PMA to remodel basolateral F-actin and abolished the stimulatory phase of basolateral endocytosis. Activation of PKCalpha stabilizes F-actin and thereby opposes the effect of PKCepsilon on membrane remodeling in T84 cells.
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Affiliation(s)
- Jaekyung Cecilia Song
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA
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11
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Wong CHY, Ko WH. Stimulation of Cl- secretion via membrane-restricted Ca2+ signaling mediated by P2Y receptors in polarized epithelia. J Biol Chem 2002; 277:9016-21. [PMID: 11779875 DOI: 10.1074/jbc.m111917200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Extracellular nucleotides such as ATP have been shown to regulate ion transport processes in a variety of epithelia. This effect is mediated by the activation of plasma membrane P2Y receptors, which leads to Ca(2+) signaling cascade. Ion transport processes (e.g. activation of apical calcium-dependent Cl(-) channels) are then stimulated via an increase in [Ca(2+)](i). Many polarized epithelia express apical and/or basolateral P2Y receptors. To test whether apical and basolateral stimulation of P2Y receptors elicit polarized Ca(2+) signaling and anion secretion, we simultaneously measured the two parameters in polarized epithelia. Although activation of P2Y receptors located at both apical and basolateral membranes evoked an increase in [Ca(2+)](i), only apical P2Y receptors-coupled Ca(2+) release stimulated an increase in anion secretion. Moreover, the calcium influx evoked by apical and basolateral P2Y receptor stimulation is predominately via the basolateral membrane domain. It appears that the apical P2Y receptor-regulated Ca(2+) release and activation of apical Cl(-) channels is compartmentalized in polarized epithelia with basolateral P2Y-stimulated Ca(2+) release failing to activate anion secretion. These data suggest that there may be two distinct ATP-releasable Ca(2+) pools, each coupled to apical and basolateral membrane receptor but linked to the same calcium influx pathway located at the basolateral membrane.
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Affiliation(s)
- Connie Hau-Yan Wong
- Department of Physiology, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong, China
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12
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Caroppo R, Gerbino A, Debellis L, Kifor O, Soybel DI, Brown EM, Hofer AM, Curci S. Asymmetrical, agonist-induced fluctuations in local extracellular [Ca(2+)] in intact polarized epithelia. EMBO J 2001; 20:6316-26. [PMID: 11707403 PMCID: PMC125728 DOI: 10.1093/emboj/20.22.6316] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We recently proposed that extracellular Ca(2+) ions participate in a novel form of intercellular communication involving the extracellular Ca(2+)-sensing receptor (CaR). Here, using Ca(2+)-selective microelectrodes, we directly measured the profile of agonist-induced [Ca(2+)]ext changes in restricted domains near the basolateral or luminal membranes of polarized gastric acid-secreting cells. The Ca(2+)-mobilizing agonist carbachol elicited a transient, La(3+)-sensitive decrease in basolateral [Ca(2+)] (average approximately 250 microM, but as large as 530 microM). Conversely, carbachol evoked an HgCl2-sensitive increase in [Ca(2+)] (average approximately 400 microM, but as large as 520 microM) in the lumen of single gastric glands. Both responses were significantly reduced by pre-treatment with sarco-endoplasmic reticulum Ca(2+) ATPase (SERCA) pump inhibitors or with the intracellular Ca(2+) chelator BAPTA-AM. Immunofluorescence experiments demonstrated an asymmetric localization of plasma membrane Ca(2+) ATPase (PMCA), which appeared to be partially co-localized with CaR and the gastric H(+)/K(+)-ATPase in the apical membrane of the acid-secreting cells. Our data indicate that agonist stimulation results in local fluctuations in [Ca(2+)]ext that would be sufficient to modulate the activity of the CaR on neighboring cells.
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Affiliation(s)
| | | | | | - Olga Kifor
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Via Amendola 165/A, 70126 Bari, Italy,
Endocrine Hypertension Division, Membrane Biology Program, Department of Medicine and Department of Surgery, Brigham and Women’s Hospital and Boston VA Healthcare System, Harvard Medical School, Boston and West Roxbury, 1400 VFW Parkway, West Roxbury, MA 02132, USA Corresponding author e-mail:
| | - David I. Soybel
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Via Amendola 165/A, 70126 Bari, Italy,
Endocrine Hypertension Division, Membrane Biology Program, Department of Medicine and Department of Surgery, Brigham and Women’s Hospital and Boston VA Healthcare System, Harvard Medical School, Boston and West Roxbury, 1400 VFW Parkway, West Roxbury, MA 02132, USA Corresponding author e-mail:
| | - Edward M. Brown
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Via Amendola 165/A, 70126 Bari, Italy,
Endocrine Hypertension Division, Membrane Biology Program, Department of Medicine and Department of Surgery, Brigham and Women’s Hospital and Boston VA Healthcare System, Harvard Medical School, Boston and West Roxbury, 1400 VFW Parkway, West Roxbury, MA 02132, USA Corresponding author e-mail:
| | - Aldebaran M. Hofer
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Via Amendola 165/A, 70126 Bari, Italy,
Endocrine Hypertension Division, Membrane Biology Program, Department of Medicine and Department of Surgery, Brigham and Women’s Hospital and Boston VA Healthcare System, Harvard Medical School, Boston and West Roxbury, 1400 VFW Parkway, West Roxbury, MA 02132, USA Corresponding author e-mail:
| | - Silvana Curci
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari, Via Amendola 165/A, 70126 Bari, Italy,
Endocrine Hypertension Division, Membrane Biology Program, Department of Medicine and Department of Surgery, Brigham and Women’s Hospital and Boston VA Healthcare System, Harvard Medical School, Boston and West Roxbury, 1400 VFW Parkway, West Roxbury, MA 02132, USA Corresponding author e-mail:
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Ito Y, Son M, Kume H, Yamaki K. Novel effects of minocycline on Ca(2+)-dependent Cl(-) secretion in human airway epithelial Calu-3 cells. Toxicol Appl Pharmacol 2001; 176:101-9. [PMID: 11601886 DOI: 10.1006/taap.2001.9261] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study concerns previously unreported effects of the antibiotic minocycline on the transepithelial Cl(-) transport in Calu-3 cells, which display electrophysiological properties consistent with human airway serous cells. Basolateral 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS, 200 microM) augmented Cl(-) secretion, which was detected as a 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB, 100 microM, a Cl(-) channel blocker)-sensitive short-circuit current (I(sc)). The DIDS-induced I(sc) was composed of Ca(2+)-activated K(+) (K(Ca)) channel-dependent and -independent components. The former was selectively inhibited by 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA/AM, 10 microM), charybdotoxin (ChTx, 100 nM), clotrimazole (10 microM), basolateral Ca(2+) removal, and basolateral minocycline (IC(50) = 20 microM). The latter was attenuated by basolateral BaCl (5 mM). In contrast, forskolin (10 microM)-induced I(sc), which is insensitive to BAPTA/AM and ChTx, was unaffected by minocycline (100 microM). ATP-induced I(sc) was partially inhibited by basolateral but not by apical minocycline. I(sc) due to basolateral application of ionomycin (1 microM) was markedly suppressed by NPPB and basolateral Ca(2+) removal. These inhibitory effects were mimicked by minocycline applied only from the basolateral side of the monolayer. In the basolateral absence of Ca(2+), 1-ethyl-2-benzimdazolinone (500 microM), a K(Ca) channel opener, generated a sustained I(sc) sensitive to ChTx. Minocycline had no significant effect on the ChTx-sensitive component of the I(sc). It is concluded that minocycline inhibits K(Ca) channel-dependent Cl(-) secretion via a blockade of Ca(2+) influx across the basolateral membrane from the extracellular side.
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Affiliation(s)
- Y Ito
- Second Division, Second Department of Internal Medicine, School of Medicine, Nagoya University, Tsurumai-cho, Nagoya, 466-8550, Japan.
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Gekle M, Freudinger R, Mildenberger S, Sauvant C. Determination of basolateral Na(+)/H(+) exchange activity in MDCK cells using a multiwell-multilabel reader. Anal Biochem 2001; 296:174-8. [PMID: 11554712 DOI: 10.1006/abio.2001.5294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na(+)/H(+) exchangers (NHE) are important membrane transport proteins involved in transepithelial transport and cellular pH homeostasis. NHE-1, important for cellular pH and volume homeostasis, is expressed in the basolateral membrane of epithelial cells. We evaluated the use of a multiwell-multilabel reader to investigate basolateral NHE-1 in confluent MDCK cells and compared the results with data obtained using an imaging system equipped with a filter perfusion system. Using the multiwell-multilabel reader we obtained virtually the same values for steady-state pH and NHE-1 activity under control conditions compared to the imaging system. With both setups Na(+)-dependent pH recovery after an acid load occurred virtually only after basolateral addition of Na(+). Furthermore, Na(+)-dependent pH recovery was reduced by >80% in the presence of the NHE-1 inhibitor HOE642. In addition, we detected an almost identical increase of NHE-1 activity with the two methods after stimulation of protein kinase C using phorbol myristate acetate. In summary, our data indicate that multiwell-multilabel readers are suitable to investigate physiology and regulation of basolateral NHE. Thus, multiwell-multilabel readers offer a valid and convenient alternative to investigate basolateral transporters.
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Affiliation(s)
- M Gekle
- Physiologisches Institut, University of Würzburg, Würzburg, 97070, Germany
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Smitham JE, Barrett KE. Differential effects of apical and basolateral uridine triphosphate on intestinal epithelial chloride secretion. Am J Physiol Cell Physiol 2001; 280:C1431-9. [PMID: 11350738 DOI: 10.1152/ajpcell.2001.280.6.c1431] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our goal was to examine the sidedness of effects of the purinergic agonist, uridine 5'-triphosphate (UTP), on Cl(-) secretion in intestinal epithelial cells. We hypothesized that UTP might exert both stimulatory and inhibitory effects. All studies were conducted with T84 intestinal epithelial cells. UTP induced Cl(-) secretion in a concentration-dependent fashion. Responses to serosally added UTP were smaller and more transient than those evoked by mucosal addition, but there was no evidence that mucosal responses involved cAMP-dependent mechanisms. Pretreatment with serosal UTP inhibited subsequent Ca(2+)-dependent Cl(-) secretion induced by carbachol or thapsigargin, or secretion induced by mucosal UTP, in a manner that was reversed by a tyrosine kinase inhibitor. The inhibitory effect of serosal UTP on Cl(-) secretion was not additive with that of carbachol, known to exert its inhibitory effects through the tyrosine kinase-dependent generation of inositol 3,4,5,6-tetrakisphosphate [Ins(3,4,5,6)P(4)]. Moreover, responses to both serosal and mucosal UTP were reduced by prior treatment of T84 cells with carbachol. Finally, serosal, but not mucosal, UTP evoked an increase in Ins(3,4,5,6)P(4). We conclude that different signaling mechanisms lie downstream of apical and basolateral UTP receptors in epithelial cells, at least in the intestine. These differences may be relevant to the use of UTP as a therapy in cystic fibrosis.
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Affiliation(s)
- J E Smitham
- Department of Medicine, University of California-San Diego School of Medicine, 200 W. Arbor Dr., San Diego, CA 92103, USA
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