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Knudsen-Clark AM, Mwangi D, Cazarin J, Morris K, Baker C, Hablitz LM, McCall MN, Kim M, Altman BJ. Circadian rhythms of macrophages are altered by the acidic pH of the tumor microenvironment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580339. [PMID: 38405770 PMCID: PMC10888792 DOI: 10.1101/2024.02.14.580339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Macrophages are prime therapeutic targets due to their pro-tumorigenic and immunosuppressive functions in tumors, but the varying efficacy of therapeutic approaches targeting macrophages highlights our incomplete understanding of how the tumor microenvironment (TME) can influence regulation of macrophages. The circadian clock is a key internal regulator of macrophage function, but how circadian rhythms of macrophages may be influenced by the tumor microenvironment remains unknown. We found that conditions associated with the TME such as polarizing stimuli, acidic pH, and elevated lactate concentrations can each alter circadian rhythms in macrophages. Circadian rhythms were enhanced in pro-resolution macrophages but suppressed in pro-inflammatory macrophages, and acidic pH had divergent effects on circadian rhythms depending on macrophage phenotype. While cyclic AMP (cAMP) has been reported to play a role in macrophage response to acidic pH, our results indicate that pH-driven changes in circadian rhythms are not mediated solely by the cAMP signaling pathway. Remarkably, clock correlation distance analysis of tumor-associated macrophages (TAMs) revealed evidence of circadian disorder in TAMs. This is the first report providing evidence that circadian rhythms of macrophages are altered within the TME. Our data further suggest that heterogeneity in circadian rhythms at the population level may underlie this circadian disorder. Finally, we sought to determine how circadian regulation of macrophages impacts tumorigenesis, and found that tumor growth was suppressed when macrophages had a functional circadian clock. Our work demonstrates a novel mechanism by which the tumor microenvironment can influence macrophage biology through altering circadian rhythms, and the contribution of circadian rhythms in macrophages to suppressing tumor growth.
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Bhuvaneshwari S, Sankaranarayanan K. Structural and Mechanistic Insights of CRAC Channel as a Drug Target in Autoimmune Disorder. Curr Drug Targets 2019; 21:55-75. [PMID: 31556856 DOI: 10.2174/1389450120666190926150258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/20/2019] [Accepted: 08/20/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND Calcium (Ca2+) ion is a major intracellular signaling messenger, controlling a diverse array of cellular functions like gene expression, secretion, cell growth, proliferation, and apoptosis. The major mechanism controlling this Ca2+ homeostasis is store-operated Ca2+ release-activated Ca2+ (CRAC) channels. CRAC channels are integral membrane protein majorly constituted via two proteins, the stromal interaction molecule (STIM) and ORAI. Following Ca2+ depletion in the Endoplasmic reticulum (ER) store, STIM1 interacts with ORAI1 and leads to the opening of the CRAC channel gate and consequently allows the influx of Ca2+ ions. A plethora of studies report that aberrant CRAC channel activity due to Loss- or gain-of-function mutations in ORAI1 and STIM1 disturbs this Ca2+ homeostasis and causes several autoimmune disorders. Hence, it clearly indicates that the therapeutic target of CRAC channels provides the space for a new approach to treat autoimmune disorders. OBJECTIVE This review aims to provide the key structural and mechanical insights of STIM1, ORAI1 and other molecular modulators involved in CRAC channel regulation. RESULTS AND CONCLUSION Understanding the structure and function of the protein is the foremost step towards improving the effective target specificity by limiting their potential side effects. Herein, the review mainly focusses on the structural underpinnings of the CRAC channel gating mechanism along with its biophysical properties that would provide the solid foundation to aid the development of novel targeted drugs for an autoimmune disorder. Finally, the immune deficiencies caused due to mutations in CRAC channel and currently used pharmacological blockers with their limitation are briefly summarized.
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Affiliation(s)
- Sampath Bhuvaneshwari
- Ion Channel Biology Laboratory, AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai -600 044, India
| | - Kavitha Sankaranarayanan
- Ion Channel Biology Laboratory, AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai -600 044, India
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3
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Nunes ADC, Alves PH, Mendes EP, Ianzer D, Castro CH. BJ-PRO-7A and BJ-PRO-10C induce vasodilatation and inotropic effects in normotensive and hypertensive rats: Role of nitric oxide and muscarinic receptors. Peptides 2018; 110:1-9. [PMID: 30355532 DOI: 10.1016/j.peptides.2018.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 09/12/2018] [Accepted: 10/17/2018] [Indexed: 02/05/2023]
Abstract
Bj-PRO-7a and Bj-PRO-10c belong to a family of proline-rich oligopeptides (PROs) identified in Bothrops jararaca (Bj) crude venom. Previous studies have shown an antihypertensive effect evoked by theses peptides. However, the mechanisms underlying the direct effects on vessels and heart remain to be unraveled. Thus, we investigated the effect of the Bj-PRO-7a and Bj-PRO-10c in the aorta and coronary arteries and in cardiac contractility in normotensive (Wistar) and hypertensive (SHR) rats. Pre-constricted aortic rings were exposed to increasing concentrations of Bj-PROs in presence or absence of muscarinic type 1 receptor antagonist (Pirenzepine), nonselective muscarinic receptor antagonist (Atropine), nitric oxide synthase inhibitor (L-NAME), guanylyl cyclase inhibitor (ODQ), adenylyl cyclase inhibitor (MDL), or argininosuccinate synthetase inhibitor (MDLA). The effects of Bj-PROs in the cardiac contractility and coronary vasomotricity were evaluated using Langendorff perfused heart preparation. The rat hearts were perfused with Bj-PRO-7a or Bj-PRO-10c in absence or presence of L-NAME, ODQ or MDL. Both Bj-PROs induced endothelium-dependent vasorelaxation in aortic rings from Wistars and SHRs. These effects were inhibited by L-NAME, ODQ or MDL. Atropine and Pirenzepine blocked the vasorelaxant effect of Bj-PRO-7a in aorta from both strains. MDLA inhibited the Bj-PRO-10c-induced vasorelaxation in aortic rings from SHR, but not Wistar. The Bj-PRO-7a induced coronary vasodilation only in SHR. L-NAME, ODQ and MDL inhibited this effect. Bj-PRO-10c induced coronary vasodilatation in both strains, which was blocked by L-NAME, ODQ and MDL. Bj-PRO-7a decreased the dP/dt max in Wistar hearts and the dP/dt min in Wistar and SHR hearts. These effects were abolished by L-NAME. Bj-PRO-10c decreased dP/dt max and dP/dt min in hearts from normotensive and hypertensive animals, which were abolished in the presence of L-NAME, MDL and ODQ. In summary, the Bj-PROs induced endothelium-dependent vasorelaxation in rat thoracic aorta, coronary vasodilation and negative inotropic effects through mechanisms mediated by activation of nitric oxide pathway.
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Affiliation(s)
- A D C Nunes
- Department of Physiological Sciences, Federal University of Goiás, Goiânia, GO, 74690-900, Brazil
| | - P H Alves
- Department of Physiological Sciences, Federal University of Goiás, Goiânia, GO, 74690-900, Brazil
| | - E P Mendes
- Department of Physiological Sciences, Federal University of Goiás, Goiânia, GO, 74690-900, Brazil
| | - D Ianzer
- Laboratory of Neural and Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Federal University of Goiás, Goiânia, 74690-900, Brazil
| | - C H Castro
- Department of Physiological Sciences, Federal University of Goiás, Goiânia, GO, 74690-900, Brazil.
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Guan C, Huang L, Ren C, Zou G. Development of a Telescoped Process for Preparation of N,O-Chelated Diarylborinates. Org Process Res Dev 2018. [DOI: 10.1021/acs.oprd.8b00109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Changwei Guan
- Department of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, China
| | - Lingyun Huang
- Department of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, China
| | - Chao Ren
- Department of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, China
| | - Gang Zou
- Department of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, China
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5
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Simo-Cheyou ER, Tan JJ, Grygorczyk R, Srivastava AK. STIM-1 and ORAI-1 channel mediate angiotensin-II-induced expression of Egr-1 in vascular smooth muscle cells. J Cell Physiol 2017; 232:3496-3509. [PMID: 28105751 DOI: 10.1002/jcp.25810] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/18/2017] [Accepted: 01/18/2017] [Indexed: 12/21/2022]
Abstract
An upregulation of Egr-1 expression has been reported in models of atherosclerosis and intimal hyperplasia and, various vasoactive peptides and growth promoting stimuli have been shown to induce the expression of Egr-1 in vascular smooth muscle cells (VSMC). Angiotensin-II (Ang-II) is a key vasoactive peptide that has been implicated in the pathogenesis of vascular diseases. Ang-II elevates intracellular Ca2+ through activation of the store-operated calcium entry (SOCE) involving an inositol-3-phosphate receptor (IP3R)-coupled depletion of endoplasmic reticular Ca2+ and a subsequent activation of the stromal interaction molecule 1 (STIM-1)/Orai-1 complex. However, the involvement of IP3R/STIM-1/Orai-1-Ca2+ -dependent signaling in Egr-1 expression in VSMC remains unexplored. Therefore, in the present studies, we have examined the role of Ca2+ signaling in Ang-II-induced Egr-1 expression in VSMC and investigated the contribution of STIM-1 or Orai-1 in mediating this response. 2-aminoethoxydiphenyl borate (2-APB), a dual non-competitive antagonist of IP3R and inhibitor of SOCE, decreased Ang-II-induced Ca2+ release and attenuated Ang-II-induced enhanced expression of Egr-1 protein and mRNA levels. Egr-1 upregulation was also suppressed following blockade of calmodulin and CaMKII. Furthermore, RNA interference-mediated depletion of STIM-1 or Orai-1 attenuated Ang-II-induced Egr-1 expression as well as Ang-II-induced phosphorylation of ERK1/2 and CREB. In addition, siRNA-induced silencing of CREB resulted in a reduction in the expression of Egr-1 stimulated by Ang-II. In summary, our data demonstrate that Ang-II-induced Egr-1 expression is mediated by STIM-1/Orai-1/Ca2+ -dependent signaling pathways in A-10 VSMC.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Calcium Channel Blockers/pharmacology
- Calcium Signaling/drug effects
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/antagonists & inhibitors
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Calmodulin/antagonists & inhibitors
- Calmodulin/metabolism
- Cell Line
- Cyclic AMP Response Element-Binding Protein/metabolism
- Dose-Response Relationship, Drug
- Early Growth Response Protein 1/genetics
- Early Growth Response Protein 1/metabolism
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/antagonists & inhibitors
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- ORAI1 Protein/genetics
- ORAI1 Protein/metabolism
- Phosphorylation
- Protein Kinase Inhibitors/pharmacology
- RNA Interference
- Rats
- Stromal Interaction Molecule 1/genetics
- Stromal Interaction Molecule 1/metabolism
- Time Factors
- Transfection
- Up-Regulation
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Affiliation(s)
- Estelle R Simo-Cheyou
- Laboratory of Cellular Signaling, Montreal Diabetes Research Center, Quebec, Canada
- CHUM-Research Center (CRCHUM), Quebec, Canada
- Faculty of Medicine, Department of Nutrition, University of Montreal, Quebec, Canada
| | - Ju Jing Tan
- CHUM-Research Center (CRCHUM), Quebec, Canada
| | - Ryszard Grygorczyk
- CHUM-Research Center (CRCHUM), Quebec, Canada
- Faculty of Medicine, Department of Medicine, University of Montreal, Quebec, Canada
| | - Ashok K Srivastava
- Laboratory of Cellular Signaling, Montreal Diabetes Research Center, Quebec, Canada
- CHUM-Research Center (CRCHUM), Quebec, Canada
- Faculty of Medicine, Department of Nutrition, University of Montreal, Quebec, Canada
- Faculty of Medicine, Department of Medicine, University of Montreal, Quebec, Canada
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6
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Keckeis S, Wernecke L, Salchow DJ, Reichhart N, Strauß O. Activation of a Ca 2+-dependent cation conductance with properties of TRPM2 by reactive oxygen species in lens epithelial cells. Exp Eye Res 2017; 161:61-70. [PMID: 28603015 DOI: 10.1016/j.exer.2017.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 05/23/2017] [Accepted: 06/01/2017] [Indexed: 02/03/2023]
Abstract
Ion channels are crucial for maintenance of ion homeostasis and transparency of the lens. The lens epithelium is the metabolically and electrophysiologically active cell type providing nutrients, ions and water to the lens fiber cells. Ca2+-dependent non-selective ion channels seem to play an important role for ion homeostasis. The aim of the study was to identify and characterize Ca2+- and reactive oxygen species (ROS)-dependent non-selective cation channels in human lens epithelial cells. RT-PCR revealed gene expression of the Ca2+-activated non-selective cation channels TRPC3, TRPM2, TRPM4 and Ano6 in both primary lens epithelial cells and the cell line HLE-B3, whereas TRPM5 mRNA was only found in HLE-B3 cells. Using whole-cell patch-clamp technique, ionomycin evoked non-selective cation currents with linear current-voltage relationship in both cell types. The current was decreased by flufenamic acid (FFA), 2-APB, 9-phenanthrol and miconazole, but insensitive to DIDS, ruthenium red, and intracellularly applied spermine. H2O2 evoked a comparable current, abolished by FFA. TRPM2 protein expression in HLE-B3 cells was confirmed by means of immunocytochemistry and western blot. In summary, we conclude that lens epithelial cells functionally express Ca2+- and H2O2-activated non-selective cation channels with properties of TRPM2.
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Affiliation(s)
- Susanne Keckeis
- Experimental Ophthalmology, Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Laura Wernecke
- Experimental Ophthalmology, Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Daniel J Salchow
- Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany
| | - Nadine Reichhart
- Experimental Ophthalmology, Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany.
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité University Medicine Berlin, Berlin, Germany.
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7
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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8
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Young RC, Schumann R, Zhang P. Nifedipine Block of Capacitative Calcium Entry in Cultured Human Uterine Smooth-Muscle Cells. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155760100800405] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Roger C. Young
- Department of Obstretrics and Gynecology, Medical University of South Carolina, Charleston, South Carolina; Department of Obstetrics and Gynecology, 96 Jonathan Lucas Street, Suite 634, Charleston, SC 29425
| | | | - Peisheng Zhang
- Department of Obstretrics and Gynecology, Medical University of South Carolina, Charleston, South Carolina
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9
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Abstract
Aberrant Ca(2+) release-activated Ca(2+) (CRAC) channel activity has been implicated in a number of human disorders, including immunodeficiency, autoimmunity, occlusive vascular diseases and cancer, thus placing CRAC channels among the important targets for the treatment of these disorders. We briefly summarize herein the molecular basis and activation mechanism of CRAC channel and focus on discussing several pharmacological inhibitors of CRAC channels with respect to their biological activity, mechanisms of action and selectivity over other types of Ca(2+) channel in different types of cells.
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10
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Dong H, Li W, Sun J, Li S, Klein ML. Understanding the Boron–Nitrogen Interaction and Its Possible Implications in Drug Design. J Phys Chem B 2015; 119:14393-401. [DOI: 10.1021/acs.jpcb.5b07783] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hao Dong
- Kuang
Yaming Honors School, Nanjing University, Nanjing, P.R. China
- Institute
for Computational Molecular Science, Temple University, 1900 North
12th Street, Philadelphia, Pennsylvania 19122-6078, United States
| | - Wei Li
- School
of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic
Chemistry of Ministry of Education, Institute of Theoretical and Computational
Chemistry, Nanjing University, Nanjing, P.R. China
| | - Jianwei Sun
- Department
of Physics, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122-6078, United States
| | - Shuhua Li
- School
of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic
Chemistry of Ministry of Education, Institute of Theoretical and Computational
Chemistry, Nanjing University, Nanjing, P.R. China
| | - Michael L. Klein
- Institute
for Computational Molecular Science, Temple University, 1900 North
12th Street, Philadelphia, Pennsylvania 19122-6078, United States
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11
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Hendron E, Wang X, Zhou Y, Cai X, Goto JI, Mikoshiba K, Baba Y, Kurosaki T, Wang Y, Gill DL. Potent functional uncoupling between STIM1 and Orai1 by dimeric 2-aminodiphenyl borinate analogs. Cell Calcium 2014; 56:482-92. [PMID: 25459299 DOI: 10.1016/j.ceca.2014.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 12/21/2022]
Abstract
The coupling of ER Ca(2+)-sensing STIM proteins and PM Orai Ca(2+) entry channels generates "store-operated" Ca(2+) signals crucial in controlling responses in many cell types. The dimeric derivative of 2-aminoethoxydiphenyl borinate (2-APB), DPB162-AE, blocks functional coupling between STIM1 and Orai1 with an IC50 (200 nM) 100-fold lower than 2-APB. Unlike 2-APB, DPB162-AE does not affect L-type or TRPC channels or Ca(2+) pumps at maximal STIM1-Orai1 blocking levels. DPB162-AE blocks STIM1-induced Orai1 or Orai2, but does not block Orai3 or STIM2-mediated effects. We narrowed the DPB162-AE site of action to the STIM-Orai activating region (SOAR) of STIM1. DPB162-AE does not prevent the SOAR-Orai1 interaction but potently blocks SOAR-mediated Orai1 channel activation, yet its action is not as an Orai1 channel pore blocker. Using the SOAR-F394H mutant which prevents both physical and functional coupling to Orai1, we reveal DPB162-AE rapidly restores SOAR-Orai binding but only slowly restores Orai1 channel-mediated Ca(2+) entry. With the same SOAR mutant, 2-APB induces rapid physical and functional coupling to Orai1, but channel activation is transient. We infer that the actions of both 2-APB and DPB162-AE are directed toward the STIM1-Orai1 coupling interface. Compared to 2-APB, DPB162-AE is a much more potent and specific STIM1/Orai1 functional uncoupler. DPB162-AE provides an important pharmacological tool and a useful mechanistic probe for the function and coupling between STIM1 and Orai1 channels.
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Affiliation(s)
- Eunan Hendron
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Xizhuo Wang
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States; Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Xiangyu Cai
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Jun-ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
| | - Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development College of Life Sciences, Beijing Normal University, Beijing 100875, PR China.
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States.
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12
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Effect of 2-aminoethoxydiphenyl borate on ischemia-reperfusion injury in a rat ovary model. Eur J Obstet Gynecol Reprod Biol 2014; 178:74-9. [DOI: 10.1016/j.ejogrb.2014.03.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 03/18/2014] [Accepted: 03/22/2014] [Indexed: 01/25/2023]
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13
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Jairaman A, Prakriya M. Molecular pharmacology of store-operated CRAC channels. Channels (Austin) 2013; 7:402-14. [PMID: 23807116 DOI: 10.4161/chan.25292] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Calcium influx through store-operated Ca(2+) release-activated Ca(2+) channels (CRAC channels) is a well-defined mechanism of generating cellular Ca(2+) elevations that regulates many functions including gene expression, exocytosis and cell proliferation. The identifications of the ER Ca(2+) sensing proteins, STIM1-2 and the CRAC channel proteins, Orai1-3, have led to improved understanding of the physiological roles and the activation mechanism of CRAC channels. Defects in CRAC channel function are associated with serious human diseases such as immunodeficiency and auto-immunity. In this review, we discuss several pharmacological modulators of CRAC channels, focusing specifically on the molecular mechanism of drug action and their utility in illuminating the mechanism of CRAC channel operation and their physiological roles in different cells.
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Affiliation(s)
- Amit Jairaman
- Department of Molecular Pharmacology and Biological Chemistry; Northwestern University, Feinberg School of Medicine; Chicago, IL USA
| | - Murali Prakriya
- Department of Molecular Pharmacology and Biological Chemistry; Northwestern University, Feinberg School of Medicine; Chicago, IL USA
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14
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Todd GK, Boosalis CA, Burzycki AA, Steinman MQ, Hester LD, Shuster PW, Patterson RL. Towards neuronal organoids: a method for long-term culturing of high-density hippocampal neurons. PLoS One 2013; 8:e58996. [PMID: 23634200 PMCID: PMC3636240 DOI: 10.1371/journal.pone.0058996] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 02/08/2013] [Indexed: 11/19/2022] Open
Abstract
One of the goals in neuroscience is to obtain tractable laboratory cultures that closely recapitulate in vivo systems while still providing ease of use in the lab. Because neurons can exist in the body over a lifetime, long-term culture systems are necessary so as to closely mimic the physiological conditions under laboratory culture conditions. Ideally, such a neuronal organoid culture would contain multiple cell types, be highly differentiated, and have a high density of interconnected cells. However, before these types of cultures can be created, certain problems associated with long-term neuronal culturing must be addressed. We sought to develop a new protocol which may further prolong the duration and integrity of E18 rat hippocampal cultures. We have developed a protocol that allows for culturing of E18 hippocampal neurons at high densities for more than 120 days. These cultured hippocampal neurons are (i) well differentiated with high numbers of synapses, (ii) anchored securely to their substrate, (iii) have high levels of functional connectivity, and (iv) form dense multi-layered cellular networks. We propose that our culture methodology is likely to be effective for multiple neuronal subtypes-particularly those that can be grown in Neurobasal/B27 media. This methodology presents new avenues for long-term functional studies in neurons.
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Affiliation(s)
- George K. Todd
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Casey A. Boosalis
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Aaron A. Burzycki
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
| | - Michael Q. Steinman
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
- Department of Psychology, University of California Davis, Davis, California, United States of America
| | - Lynda D. Hester
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | - Randen L. Patterson
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- * E-mail:
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15
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Emery AC, Eiden MV, Eiden LE. A new site and mechanism of action for the widely used adenylate cyclase inhibitor SQ22,536. Mol Pharmacol 2012; 83:95-105. [PMID: 23053667 DOI: 10.1124/mol.112.081760] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We evaluated the efficacy, potency, and selectivity of the three most commonly used adenylate cyclase (AC) inhibitors in a battery of cell lines constructed to study signaling via three discrete cAMP sensors identified in neuroendocrine cells. SQ22,536 [9-(tetrahydrofuryl)-adenine] and 2',5'-dideoxyadenosine (ddAd) are effective and potent AC inhibitors in HEK293 cells expressing a cAMP response element (CRE) reporter gene, and MDL-12,330A [cis-N-(2-phenylcyclopentyl)azacyclotridec-1-en-2-amine hydrochloride] is not. Neuroscreen-1 (NS-1) cells were used to assess the specificity of the most potent AC inhibitor, SQ22,536, to block downstream cAMP signaling to phosphorylate CREB (via PKA); to activate Rap1 (via Epac); and to activate ERK signaling leading to neuritogenesis (via the newly described neuritogenic cAMP sensor NCS). SQ22,536 failed to inhibit the effects of cAMP analogs 8-Br-cAMP and 8-CPT-2'-O-Me-cAMP on PKA-mediated CREB activation/phosphorylation and Epac-mediated Rap1 activation, indicating that it does not inhibit these cAMP pathways beyond the level of AC. On the other hand, SQ22,536, but not ddAd, inhibited the effects of cAMP analogs 8-Br-cAMP and 8-CPT-cAMP on ERK phosphorylation and neuritogenesis, indicating that it acts not only as an AC blocker, but also as an inhibitor of the NCS. The observed off-target actions of SQ22,536 are specific to cAMP signaling: SQ22,536 does not block the actions of compounds not related to cAMP signaling, including ERK induction by PMA, and ERK activation and neuritogenesis induced by NGF. These data led us to indicate a second target for SQ22,536 that should be considered when interpreting its effects in whole cell and in vivo experiments.
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Affiliation(s)
- Andrew C Emery
- National Institute of Mental Health, 49 Convent Drive, Building 49, Room 5A-38, Bethesda, MD 20892-4090, USA
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16
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Takahashi N, Kozai D, Mori Y. TRP channels: sensors and transducers of gasotransmitter signals. Front Physiol 2012; 3:324. [PMID: 22934072 PMCID: PMC3429092 DOI: 10.3389/fphys.2012.00324] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Accepted: 07/24/2012] [Indexed: 12/12/2022] Open
Abstract
The transient receptor potential (trp) gene superfamily encodes cation channels that act as multimodal sensors for a wide variety of stimuli from outside and inside the cell. Upon sensing, they transduce electrical and Ca2+ signals via their cation channel activities. These functional features of TRP channels allow the body to react and adapt to different forms of environmental changes. Indeed, members of one class of TRP channels have emerged as sensors of gaseous messenger molecules that control various cellular processes. Nitric oxide (NO), a vasoactive gaseous molecule, regulates TRP channels directly via cysteine (Cys) S-nitrosylation or indirectly via cyclic GMP (cGMP)/protein kinase G (PKG)-dependent phosphorylation. Recent studies have revealed that changes in the availability of molecular oxygen (O2) also control the activation of TRP channels. Anoxia induced by O2-glucose deprivation and severe hypoxia (1% O2) activates TRPM7 and TRPC6, respectively, whereas TRPA1 has recently been identified as a novel sensor of hyperoxia and mild hypoxia (15% O2) in vagal and sensory neurons. TRPA1 also detects other gaseous molecules such as hydrogen sulfide (H2S) and carbon dioxide (CO2). In this review, we focus on how signaling by gaseous molecules is sensed and integrated by TRP channels.
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Affiliation(s)
- Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University Kyoto, Japan
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17
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The CatSper channel: a polymodal chemosensor in human sperm. EMBO J 2012; 31:1654-65. [PMID: 22354039 DOI: 10.1038/emboj.2012.30] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/18/2012] [Indexed: 01/10/2023] Open
Abstract
The sperm-specific CatSper channel controls the intracellular Ca(2+) concentration ([Ca(2+)](i)) and, thereby, the swimming behaviour of sperm. In humans, CatSper is directly activated by progesterone and prostaglandins-female factors that stimulate Ca(2+) influx. Other factors including neurotransmitters, chemokines, and odorants also affect sperm function by changing [Ca(2+)](i). Several ligands, notably odorants, have been proposed to control Ca(2+) entry and motility via G protein-coupled receptors (GPCRs) and cAMP-signalling pathways. Here, we show that odorants directly activate CatSper without involving GPCRs and cAMP. Moreover, membrane-permeable analogues of cyclic nucleotides that have been frequently used to study cAMP-mediated Ca(2+) signalling also activate CatSper directly via an extracellular site. Thus, CatSper or associated protein(s) harbour promiscuous binding sites that can host various ligands. These results contest current concepts of Ca(2+) signalling by GPCR and cAMP in mammalian sperm: ligands thought to activate metabotropic pathways, in fact, act via a common ionotropic mechanism. We propose that the CatSper channel complex serves as a polymodal sensor for multiple chemical cues that assist sperm during their voyage across the female genital tract.
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18
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Zhang XB, Spergel DJ. Kisspeptin inhibits high-voltage activated Ca2+ channels in GnRH neurons via multiple Ca2+ influx and release pathways. Neuroendocrinology 2012; 96:68-80. [PMID: 22343183 DOI: 10.1159/000335985] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 12/20/2011] [Indexed: 12/26/2022]
Abstract
Kisspeptin plays an important role in puberty and subsequent fertility by activating its receptor, G-protein-coupled receptor 54 (GPR54), and increasing cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) and gonadotropin-releasing hormone (GnRH) secretion in GnRH neurons. Yet the mechanism by which kisspeptin increases [Ca(2+)](i) in GnRH neurons remains to be fully elucidated. In other neurons, voltage-gated Ca(2+) channel (VGCC) activity has been shown to be inversely related to [Ca(2+)](i). We used whole-cell patch-clamp recording to examine the effects of kisspeptin-10 (KP-10) on VGCC activity evoked by step depolarizations in GnRH neurons in brain slices from pubertal male GnRH-green fluorescent protein transgenic mice. Prolonged (>30 s) KP-10 application inhibited Ca(2+) currents. The GPR54 antagonist peptide 234, chelation of intracellular Ca(2+) by 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid, substitution of Ba(2+) for Ca(2+), the calmodulin antagonists calmidazolium and trifluoperazine, the phospholipase C inhibitor edelfosine, the canonical transient receptor potential (TRPC) channel and inositol 1,4,5-trisphosphate receptor (IP(3)R) antagonist 2-APB, the TRPC channel antagonist BTP2 and the endoplasmic reticulum Ca(2+)-ATPase blocker cyclopiazonic acid each prevented inhibition. The IP(3)R antagonists caffeine (10 µM), heparin and intracellular 2-APB prevented inhibition to a lesser extent. The ryanodine receptor (RyR) antagonists ryanodine and dantrolene prevented inhibition, and the RyR agonist caffeine (30 mM) mimicked the effects of KP-10 on Ca(2+) currents. Our results suggest that kisspeptin induces Ca(2+) influx through TRPC channels and Ca(2+) release via IP(3)Rs and RyRs, and that this is followed by Ca(2+)/CaM-dependent inhibition of VGCCs.
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Affiliation(s)
- Xiao-Bing Zhang
- Section of Endocrinology, Department of Medicine, University of Chicago, Chicago, Ill., USA
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Pan L, Wu X, Zhao D, Hessari NM, Lee I, Zhang X, Xu J. Sulfhydryl modification induces calcium entry through IP₃-sensitive store-operated pathway in activation-dependent human neutrophils. PLoS One 2011; 6:e25262. [PMID: 21984909 PMCID: PMC3184953 DOI: 10.1371/journal.pone.0025262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 08/30/2011] [Indexed: 11/23/2022] Open
Abstract
As the first line of host defense, neutrophils are stimulated by pro-inflammatory cytokines from resting state, facilitating the execution of immunomodulatory functions in activation state. Sulfhydryl modification has a regulatory role in a wide variety of physiological functions through mediation of signaling transductions in various cell types. Recent research suggested that two kinds of sulfhydryl modification, S-nitrosylation by exogenous nitric oxide (NO) and alkylation by N-ethylmaleimide (NEM), could induce calcium entry through a non-store-operated pathway in resting rat neutrophils and DDT1MF-2 cells, while in active human neutrophils a different process has been observed by us. In the present work, data showed that NEM induced a sharp rising of cytosolic calcium concentration ([Ca2+]c) without external calcium, followed by a second [Ca2+]c increase with readdition of external calcium in phorbol 12-myristate 13-acetate (PMA)-activated human neutrophils. Meanwhile, addition of external calcium did not cause [Ca2+]c change of Ca2+-free PMA-activated neutrophils before application of NEM. These data indicated that NEM could induce believable store-operated calcium entry (SOCE) in PMA-activated neutrophils. Besides, we found that sodium nitroprusside (SNP), a donor of exogenous NO, resulted in believable SOCE in PMA-activated human neutrophils via S-nitrosylation modification. In contrast, NEM and SNP have no effect on [Ca2+]c of resting neutrophils which were performed in suspension. Furthermore, 2-Aminoethoxydiphenyl borate, a reliable blocker of SOCE and an inhibitor of inositol 1,4,5-trisphosphate (IP3) receptor, evidently abolished SNP and NEM-induced calcium entry at 75 µM, while preventing calcium release in a concentration-dependent manner. Considered together, these results demonstrated that NEM and SNP induced calcium entry through an IP3-sensitive store-operated pathway of human neutrophils via sulfhydryl modification in a PMA-induced activation-dependent manner.
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Affiliation(s)
- Leiting Pan
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin, People's Republic of China.
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20
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Abstract
The endothelium is a highly dynamic structure lining the inside of blood vessels that exhibits physical and chemical properties that are critical determinants of overall vascular function. Physically, the endothelium constitutes a semipermeable barrier. Chemically, the endothelium synthesizes numerous factors such as reactive oxygen species (ROS) that can act as autocrine and paracrine signaling molecules. Oxidative stress results when ROS levels increase to levels that cause cellular injury, and, in the endothelium oxidative stress leads to barrier disruption. Endothelial barrier disruption also results from increased cytosolic calcium through store-operated calcium (SOC) entry channels. Although it is known that ROS can interact with and regulate some ion channels, relatively little is known about the interaction of these species with components of endothelial SOC entry channels, the canonical transient receptor potential (TRPC) proteins. Here we review our current understanding of ROS-mediated TRPC channel function and how it affects SOC entry and endothelial barrier disruption.
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Affiliation(s)
- Donna L Cioffi
- Department of Biochemistry and Molecular Biology, Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36688, USA.
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21
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Extracellular acidification induces connective tissue growth factor production through proton-sensing receptor OGR1 in human airway smooth muscle cells. Biochem Biophys Res Commun 2011; 413:499-503. [PMID: 21907704 DOI: 10.1016/j.bbrc.2011.08.087] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 08/17/2011] [Indexed: 11/20/2022]
Abstract
Asthma is characterized by airway inflammation, hyper-responsiveness and remodeling. Extracellular acidification is known to be associated with severe asthma; however, the role of extracellular acidification in airway remodeling remains elusive. In the present study, the effects of acidification on the expression of connective tissue growth factor (CTGF), a critical factor involved in the formation of extracellular matrix proteins and hence airway remodeling, were examined in human airway smooth muscle cells (ASMCs). Acidic pH alone induced a substantial production of CTGF, and enhanced transforming growth factor (TGF)-β-induced CTGF mRNA and protein expression. The extracellular acidic pH-induced effects were inhibited by knockdown of a proton-sensing ovarian cancer G-protein-coupled receptor (OGR1) with its specific small interfering RNA and by addition of the G(q/11) protein-specific inhibitor, YM-254890, or the inositol-1,4,5-trisphosphate (IP(3)) receptor antagonist, 2-APB. In conclusion, extracellular acidification induces CTGF production through the OGR1/G(q/11) protein and inositol-1,4,5-trisphosphate-induced Ca(2+) mobilization in human ASMCs.
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22
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Harteneck C, Gollasch M. Pharmacological modulation of diacylglycerol-sensitive TRPC3/6/7 channels. Curr Pharm Biotechnol 2011; 12:35-41. [PMID: 20932261 PMCID: PMC3267170 DOI: 10.2174/138920111793937943] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 05/13/2010] [Indexed: 01/03/2023]
Abstract
Members of the classic type of transient receptor potential channels (TRPC) represent important molecules involved in hormonal signal transduction. TRPC3/6/7 channels are of particular interest as they are components of phospholipase C driven signalling pathways. Upon receptor-activation, G-protein-mediated stimulation of phospholipase C results in breakdown of phosphatidylinositides leading to increased intracellular diacylglycerol and inositol-trisphosphate levels. Diacylglycerol activates protein kinase C, but more interestingly diacylglycerol directly activates TRPC2/3/6/7 channels. Molecular cloning, expression and characterization of TRP channels enabled reassignment of traditional inhibitors of receptor-dependent calcium entry such as SKF-96365 and 2-APB as blockers of TRPC3/6/7 and several members of non-classic TRP channels. Furthermore, several enzyme inhibitors have also been identified as TRP channel blockers, such as ACA, a phospholipase A2 inhibitor, and W-7, a calmodulin antagonist. Finally, the naturally occurring secondary plant compound hyperforin has been identified as TRPC6-selective drug, providing an exciting proof of concept that it is possible to generate TRPC-selective channel modulators. The description of Pyr3 as the first TRPC3-selective inhibitor shows that not only nature but also man is able to generate TRP-selective modulators. The review sheds lights on the current knowledge and historical development of pharmacological modulators of TRPC3/6/7. Our analysis indicates that Pyr3 and hyperforin provide promising core structures for the development of new, selective and more potent modulators of TRPC3/6/7 activity.
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Affiliation(s)
- Christian Harteneck
- Institut für Pharmakologie & Toxikologie, Eberhard-Karls-Universitát, Wilhelmstraße 56, 72074 Tübingen, Germany.
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23
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Harteneck C, Klose C, Krautwurst D. Synthetic modulators of TRP channel activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:87-106. [PMID: 21290290 DOI: 10.1007/978-94-007-0265-3_4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In humans, 27 TRP channels from 6 related families contribute to a broad spectrum of cellular functions, such as thermo-, pressure-, volume-, pain- and chemosensation. Pain and inflammation-inducing compounds represent potent plant and animal defense mechanisms explaining the great variety of the naturally occurring, TRPV1-, TRPM8-, and TRPA1-activating ligands. The discovery of the first vanilloid receptor (TRPV1) and its involvement in nociception triggered the euphoria and the hope in novel therapeutic strategies treating pain, and this clear-cut indication inspired the development of TRPV1-selective ligands. On the other hand the nescience in the physiological role and putative clinical indication hampered the development of a selective drug in the case of the other TRP channels. Therefore, currently only a handful of mostly un-selective blocker is available to target TRP channels. Nevertheless, there is an ongoing quest for new, natural or synthetic ligands and modulators. In this chapter, we will give an overview on available broad-range blocker, as well as first TRP channel-selective compounds.
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Affiliation(s)
- Christian Harteneck
- Institute for Pharmacology and Toxicology, Interfaculty Center of Pharmacogenomics and Pharmaceutical Research (ICEPHA), Eberhard-Karls-University, Tübingen, Germany.
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24
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Castella LF, Buscemi L, Godbout C, Meister JJ, Hinz B. A new lock-step mechanism of matrix remodelling based on subcellular contractile events. J Cell Sci 2010; 123:1751-60. [PMID: 20427321 DOI: 10.1242/jcs.066795] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Myofibroblasts promote tissue contractures during fibrotic diseases. To understand how spontaneous changes in the intracellular calcium concentration, [Ca(2+)](i), contribute to myofibroblast contraction, we analysed both [Ca(2+)](i) and subcellular contractions. Contractile events were assessed by tracking stress-fibre-linked microbeads and measured by atomic force microscopy. Myofibroblasts exhibit periodic (approximately 100 seconds) [Ca(2+)](i) oscillations that control small (approximately 400 nm) and weak (approximately 100 pN) contractions. Whereas depletion of [Ca(2+)](i) reduces these microcontractions, cell isometric tension is unaffected, as shown by growing cells on deformable substrates. Inhibition of Rho- and ROCK-mediated Ca(2+)-independent contraction has no effect on microcontractions, but abolishes cell tension. On the basis of this two-level regulation of myofibroblast contraction, we propose a single-cell lock-step model. Rho- and ROCK-dependent isometric tension generates slack in extracellular matrix fibrils, which are then accessible for the low-amplitude and high-frequency contractions mediated by [Ca(2+)](i). The joint action of both contraction modes can result in macroscopic tissue contractures of approximately 1 cm per month.
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25
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Abstract
The Ca2+release-activated Ca2+ (CRAC) channel is a highly Ca2+-selective store-operated channel expressed in T cells, mast cells, and various other tissues. CRAC channels regulate critical cellular processes such as gene expression, motility, and the secretion of inflammatory mediators. The identification of Orai1, a key subunit of the CRAC channel pore, and STIM1, the endoplasmic reticulum (ER) Ca2+ sensor, have provided the tools to illuminate the mechanisms of regulation and the pore properties of CRAC channels. Recent evidence indicates that the activation of CRAC channels by store depletion involves a coordinated series of steps, which include the redistributions of STIM1 and Orai1, direct physical interactions between these proteins, and conformational changes in Orai1, culminating in channel activation. Additional studies have revealed that the high Ca2+ selectivity of CRAC channels arises from the presence of an intrapore Ca2+ binding site, the properties of which are finely honed to occlude the permeation of the much more prevalent Na+. Structure-function studies have led to the identification of the potential pore-binding sites for Ca2+, providing a firm framework for understanding the mechanisms of selectivity and gating of the CRAC channel. This review summarizes recent progress in understanding the mechanisms of CRAC channel activation, pore properties, and modulation.
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Affiliation(s)
- Murali Prakriya
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University School of Medicine, Chicago, IL 60611, USA.
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26
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Schilling T, Eder C. Non-selective cation channel activity is required for lysophosphatidylcholine-induced monocyte migration. J Cell Physiol 2009; 221:325-34. [DOI: 10.1002/jcp.21857] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Activation of metabotropic glutamate receptors induces periodic burst firing and concomitant cytosolic Ca2+ oscillations in cerebellar interneurons. J Neurosci 2009; 29:9281-91. [PMID: 19625518 DOI: 10.1523/jneurosci.1865-09.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Little is known about the generation of slow rhythms in brain neuronal circuits. Nevertheless, a few studies, both from reconstituted systems and from hippocampal slices, indicate that activation of metabotropic glutamate receptors (mGluRs) could generate such rhythms. Here we show in rat cerebellar slices that after either release of glutamate by repetitive stimulation, or direct stimulation of type 1 mGluRs, molecular layer interneurons exhibit repetitive slow Ca(2+) transients. By combining cell-attached patch-clamp recording with Ca(2+) imaging, we show that the regular Ca(2+) transients (mean frequency, 35 mHz induced by 2 microm quisqualate in the presence of ionotropic glutamate receptor blockers) are locked with bursts of action potentials. Nevertheless, the Ca(2+) transients are not blocked by tetrodotoxin, indicating that firing is not necessary to entrain oscillations. The first Ca(2+) transient within a train is different in several ways from subsequent transients. It is broader than the subsequent transients, displays a different phase relationship to associated spike bursts, and exhibits a distinct sensitivity to ionic and pharmacological manipulations. Whereas the first transient appears to involve entry of Ca(2+) ions through transient receptor potential channel-like channels and secondarily activated L-type Ca(2+) channels, subsequent transients rely mostly on an exchange of Ca(2+) ions between the cytosol and D-myo-inositol-1,4,5-triphosphate-sensitive intracellular Ca(2+) stores. The slow, highly regular oscillations observed in the present work are likely to drive pauses in postsynaptic Purkinje cells, and could play a role in coordinating slow oscillations involving the cerebello-olivar circuit loop.
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28
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Martínez MC, Andriantsitohaina R. Reactive nitrogen species: molecular mechanisms and potential significance in health and disease. Antioxid Redox Signal 2009; 11:669-702. [PMID: 19014277 DOI: 10.1089/ars.2007.1993] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reactive nitrogen species (RNS) are various nitric oxide-derived compounds, including nitroxyl anion, nitrosonium cation, higher oxides of nitrogen, S-nitrosothiols, and dinitrosyl iron complexes. RNS have been recognized as playing a crucial role in the physiologic regulation of many, if not all, living cells, such as smooth muscle cells, cardiomyocytes, platelets, and nervous and juxtaglomerular cells. They possess pleiotropic properties on cellular targets after both posttranslational modifications and interactions with reactive oxygen species. Elevated levels of RNS have been implicated in cell injury and death by inducing nitrosative stress. The aim of this comprehensive review is to address the mechanisms of formation and removal of RNS, highlighting their potential cellular targets: lipids, DNA, and proteins. The specific importance of RNS and their paradoxic effects, depending on their local concentration under physiologic conditions, is underscored. An increasing number of compounds that modulate RNS processing or targets are being identified. Such compounds are now undergoing preclinical and clinical evaluations in the treatment of pathologies associated with RNS-induced cellular damage. Future research should help to elucidate the involvement of RNS in the therapeutic effect of drugs used to treat neurodegenerative, cardiovascular, metabolic, and inflammatory diseases and cancer.
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Affiliation(s)
- M Carmen Martínez
- INSERM, U771, CNRS UMR, 6214, and Université d' Angers, Angers, France
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29
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Pan L, Zhang X, Song K, Wu X, Xu J. Exogenous nitric oxide-induced release of calcium from intracellular IP3 receptor-sensitive stores via S-nitrosylation in respiratory burst-dependent neutrophils. Biochem Biophys Res Commun 2008; 377:1320-5. [PMID: 19000903 DOI: 10.1016/j.bbrc.2008.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 11/03/2008] [Indexed: 12/19/2022]
Abstract
PMA-induced respiratory burst neutrophils were exposed to exogenous nitric oxide (NO) donor sodium nitroprusside (SNP) to study the effect of NO on calcium signaling. A sharp rise of cytosolic calcium concentration ([Ca(2+)](c)) was triggered by 1mM SNP with and without external calcium. We found that GF 109203X, a specific inhibitor of protein kinase C, DPI, a putative inhibitor of the respiratory burst-generating NADPH oxidase, and 2-DG, a non-metabolizable analog of glucose, completely inhibited the SNP-induced rise of [Ca(2+)](c) in PMA-activated respiratory burst neutrophils. Meanwhile, 2-APB and TMB-8, two potent IP(3) receptor inhibitors, prevented calcium increase respectively. Furthermore, N-ethylmaleimide (NEM), a specific cysteine alkylating agent, evidently abolished the [Ca(2+)](c) elevation. In contrast, the sGC inhibitor NS2028 had little effect on the rise of [Ca(2+)](c). Taken together, these results indicated that exogenous NO induced the release of calcium from intracellular IP(3) receptor-sensitive stores of neutrophils via S-nitrosylation in a respiratory burst-dependent manner.
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Affiliation(s)
- Leiting Pan
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, Institute of Physics and TEDA Applied Physics School, Nankai University, Tianjin 300457, China
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Poley RN, Dosier CR, Speich JE, Miner AS, Ratz PH. Stimulated calcium entry and constitutive RhoA kinase activity cause stretch-induced detrusor contraction. Eur J Pharmacol 2008; 599:137-45. [PMID: 18929558 DOI: 10.1016/j.ejphar.2008.09.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 09/25/2008] [Accepted: 09/29/2008] [Indexed: 11/26/2022]
Abstract
Urinary bladder wall muscle (i.e., detrusor smooth muscle; DSM) contracts in response to a quick-stretch, but this response is neither fully characterized, nor completely understood at the subcellular level. Strips of rabbit DSM were quick-stretched (5 ms) and held isometric for 10 s to measure the resulting peak quick-stretch contractile response (PQSR). The ability of selective Ca(2+) channel blockers and kinase inhibitors to alter the PQSR was measured, and the phosphorylation levels of myosin light chain (MLC) and myosin phosphatase targeting regulatory subunit (MYPT1) were recorded. DSM responded to a quick-stretch with a biphasic response consisting of an initial contraction peaking at 0.24+/-0.02-fold the maximum KCl-induced contraction (F(o)) by 1.48+/-0.17 s (PQSR) before falling to a weaker tonic (10 s) level (0.12+/-0.03-fold F(o)). The PQSR was dependent on the rate and degree of muscle stretch, displayed a refractory period, and was converted to a sustained response in the presence of muscarinic receptor stimulation. The PQSR was inhibited by nifedipine, 2-aminoethoxydiphenyl borate (2-APB), 100 microM gadolinium and Y-27632, but not by atropine, 10 microM gadolinium, LOE-908, cyclopiazonic acid, or GF-109203X. Y-27632 and nifedipine abolished the increase in MLC phosphorylation induced by a quick-stretch. Y-27632, but not nifedipine, inhibited basal MYPT1 phosphorylation, and a quick-stretch failed to increase phosphorylation of this rhoA kinase (ROCK) substrate above the basal level. These data support the hypothesis that constitutive ROCK activity is required for a quick-stretch to activate Ca(2+) entry and cause a myogenic contraction of DSM.
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Affiliation(s)
- Rainer N Poley
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, School of Medicine, PO Box 980614, Richmond, VA 23298-0614, United States
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Li N, Zheng L, Lin P, Danielpour D, Pan Z, Ma J. Overexpression of Bax induces down-regulation of store-operated calcium entry in prostate cancer cells. J Cell Physiol 2008; 216:172-9. [PMID: 18247359 DOI: 10.1002/jcp.21385] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Store-operated Ca2+ channels control homeostasis between extracellular Ca2+ reservoir and intracellular Ca2+ storage and play important roles in apoptosis in a wide variety of cells, including prostate epithelia. Recent studies have shown that the acquired apoptosis-resistant nature of androgen-independent prostate cancer is associated with reduced function of store-operated Ca2+ entry (SOCE). This study investigates the functional interaction between Bax and SOCE in the apoptosis signaling cascade in prostate cancer. Our previous findings show that NRP-154, an androgen-independent prostate cancer cell line, could sustain overexpression of exogenous Bax without undergoing apoptosis. Here we show that sustained overexpression of Bax in NRP-154 cells leads to down-regulation of SOCE and reduced Ca2+ storage inside the endoplasmic reticulum. While reduced SOCE may represent an adaptive mechanism for cell survival, increased levels of Bax in the latent state enhances the sensitivity of NRP-154 cells to TGF-beta and thapsigargin-induced apoptosis. This enhanced apoptosis can be reduced by 2-aminoethoxydiphenyl borate (2-APB), an inhibitor of SOCE, or reversed under conditions where SOCE is only partially activated. Our results demonstrate a functional interaction between Bax and SOCE in apoptosis of prostate cancer, and support the concept that improving this interaction has therapeutic implications for prostate cancer.
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Affiliation(s)
- Na Li
- Department of Physiology and Biophysics, University of Medicine & Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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Zhang C, Roepke TA, Kelly MJ, Rønnekleiv OK. Kisspeptin depolarizes gonadotropin-releasing hormone neurons through activation of TRPC-like cationic channels. J Neurosci 2008; 28:4423-34. [PMID: 18434521 PMCID: PMC6670958 DOI: 10.1523/jneurosci.5352-07.2008] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 03/17/2008] [Accepted: 03/19/2008] [Indexed: 11/21/2022] Open
Abstract
Kisspeptin and its cognate receptor, GPR54, are critical for reproductive development and for the regulation of gonadotropin-releasing hormone (GnRH) secretion. Although kisspeptin has been found to depolarize GnRH neurons, the underlying ionic mechanism has not been elucidated. Presently, we found that kisspeptin depolarized GnRH neurons in a concentration-dependent manner with a maximum depolarization of 22.6 +/- 0.6 mV and EC(50) of 2.8 +/- 0.2 nM. Under voltage-clamp conditions, kisspeptin induced an inward current of 18.2 +/- 1.6 pA (V(hold) = -60 mV) that reversed near -115 mV in GnRH neurons. The more negative reversal potential than E(K)(+) (-90 mV) was caused by the concurrent inhibition of barium-sensitive, inwardly rectifying (Kir) potassium channels and activation of sodium-dependent, nonselective cationic channels (NSCCs). Indeed, reducing extracellular Na(+) (to 5 mM) essentially eliminated the kisspeptin-induced inward current. The current-voltage relationships of the kisspeptin-activated NSCC currents exhibited double rectification with negative slope conductance below -40 mV in the majority of the cells. Pharmacological examination showed that the kisspeptin-induced inward currents were blocked by TRPC (canonical transient receptor potential) channel blockers 2-APB (2-aminoethyl diphenylborinate), flufenamic acid, SKF96365 (1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride), and Cd(2+), but not by lanthanum (100 microM). Furthermore, single-cell reverse transcription-PCR analysis revealed that TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7 subunits were expressed in GnRH neurons. Therefore, it appears that kisspeptin depolarizes GnRH neurons through activating TRPC-like channels and, to a lesser extent, inhibition of Kir channels. These actions of kisspeptin contribute to the pronounced excitation of GnRH neurons that is critical for mammalian reproduction.
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Affiliation(s)
| | | | | | - Oline K. Rønnekleiv
- Departments of Physiology and Pharmacology and
- Anesthesiology and Perioperative Medicine, and
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Portland, Oregon 97239-3089
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Essin K, Welling A, Hofmann F, Luft FC, Gollasch M, Moosmang S. Indirect coupling between Cav1.2 channels and ryanodine receptors to generate Ca2+ sparks in murine arterial smooth muscle cells. J Physiol 2007; 584:205-19. [PMID: 17673505 PMCID: PMC2277062 DOI: 10.1113/jphysiol.2007.138982] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In arterial vascular smooth muscle cells (VSMCs), Ca(2+) sparks stimulate nearby Ca(2+)-activated K(+) (BK) channels that hyperpolarize the membrane and close L-type Ca(2+) channels. We tested the contribution of L-type Ca(v)1.2 channels to Ca(2+) spark regulation in tibial and cerebral artery VSMCs using VSMC-specific Ca(v)1.2 channel gene disruption in (SMAKO) mice and an approach based on Poisson statistical analysis of activation frequency and first latency of elementary events. Ca(v)1.2 channel gene inactivation reduced Ca(2+) spark frequency and amplitude by approximately 50% and approximately 80%, respectively. These effects were associated with lower global cytosolic Ca(2+) levels and reduced sarcoplasmic reticulum (SR) Ca(2+) load. Elevating cytosolic Ca(2+) levels reversed the effects completely. The activation frequency and first latency of elementary events in both wild-type and SMAKO VSMCs weakly reflected the voltage dependency of L-type channels. This study provides evidence that local and tight coupling between the Ca(v)1.2 channels and ryanodine receptors (RyRs) is not required to initiate Ca(2+) sparks. Instead, Ca(v)1.2 channels contribute to global cytosolic [Ca(2+)], which in turn influences luminal SR calcium and thus Ca(2+) sparks.
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Affiliation(s)
- Kirill Essin
- Department of Nephrology and Medical Intensive Care, Charité Campus Virchow-Klinikum, Berlin, Germany
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34
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Hung AY, Magoski NS. Activity-Dependent Initiation of a Prolonged Depolarization in Aplysia Bag Cell Neurons: Role for a Cation Channel. J Neurophysiol 2007; 97:2465-79. [PMID: 17353554 DOI: 10.1152/jn.00941.2006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The translation of prior activity into changes in excitability is essential for memory and the initiation of behavior. After brief synaptic input, the bag cell neurons of Aplysia californica undergo a nearly 30-min afterdischarge to release egg-laying hormone. The present study examines a prolonged depolarization in cultured bag cell neurons. A 5-Hz, 10-s action potential train elicited a depolarization of about 10 mV, which lasted ≤30 min and was reduced by calmodulin kinase inhibition. Very broad action potentials (resulting from TEA application) decreased prolonged depolarization amplitude, indicating that strong Ca2+ influx did not necessarily promote the response. The prolonged depolarization current ( IPD) was recorded after 5-Hz, 10-s trains of square voltage pulses of varying duration (10–150 ms). Despite Ca2+ influx increasing steadily with pulse duration, IPD was most reliably initiated at 100 ms, suggesting a Ca2+ window or limit exists for triggering IPD. Consistent with this, modestly broader action potentials, evoked by lengthening the train current-pulse duration, resulted in smaller prolonged depolarizations. With respect to the properties of IPD, it displayed a linear current–voltage relationship with a reversal potential of about −45 mV that was shifted to approximately −25 mV by lowering internal K+ or about −56 mV by lowering external Na+ and Ca2+. IPD was blocked by Gd3+, but was not antagonized by MDL-123302A, SKF-96365, 2-APB, tetrodotoxin, or flufenamic acid. Optimal Ca2+ influx may activate calmodulin kinase and a voltage-independent, nonselective cation channel to initiate the prolonged depolarization, thereby contributing to the afterdischarge and reproduction.
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Affiliation(s)
- Anne Y Hung
- Department of Physiology, Queen's University, 4th Floor, Botterell Hall, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada
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35
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Colton CK, Zhu MX. 2-Aminoethoxydiphenyl borate as a common activator of TRPV1, TRPV2, and TRPV3 channels. Handb Exp Pharmacol 2007:173-87. [PMID: 17217057 PMCID: PMC4458144 DOI: 10.1007/978-3-540-34891-7_10] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
2-Aminoethoxydiphenyl borate (2APB) had been depicted as a universal blocker of transient receptor potential (TRP) channels. While evidence has accumulated showing that some TRP channels are indeed inhibited by 2APB, especially in heterologous expression systems, there are other TRP channels that are unaffected or affected very little by this compound. More interestingly, the thermosensitive TRPV1, TRPV2, and TRPV3 channels are activated by 2APB. This has been demonstrated both in heterologous systems and in native tissues that express these channels. A number of 2APB analogs have been examined for their effects on native store-operated channels and heterologously expressed TRPV3. These studies revealed a complex mechanism of action for 2APB and its analogs on ion channels. In this review, we have summarized the current results on 2APB-induced activation of TRPV1-3 and discussed the potential mechanisms by which 2APB may regulate TRP channels.
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Affiliation(s)
- C K Colton
- Department of Neuroscience, Center for Molecular Neurobiology, The Ohio State University, Columbus, OH 43210, USA
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Schwarz EC, Wolfs MJ, Tonner S, Wenning AS, Quintana A, Griesemer D, Hoth M. TRP channels in lymphocytes. Handb Exp Pharmacol 2007:445-56. [PMID: 17217072 DOI: 10.1007/978-3-540-34891-7_26] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
TRP proteins form ion channels that are activated following receptor stimulation. Several members of the TRP family are likely to be expressed in lymphocytes. However, in many studies, messenger RNA (mRNA) but not protein expression was analyzed and cell lines but not primary human or murine lymphocytes were used. Among the expressed TRP mRNAs are TRPC1, TRPC3, TRPM2, TRPM4, TRPM7, TRPV1, and TRPV2. Regulation of Ca2+ entry is a key process for lymphocyte activation, and TRP channels may both increase Ca2+ influx (such as TRPC3) or decrease Ca2+ influx through membrane depolarization (such as TRPM4). In the future, linking endogenous Ca2+/cation channels in lymphocytes with TRP proteins should lead to a better molecular understanding of lymphocyte activation.
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Affiliation(s)
- E C Schwarz
- Institut für Physiologie, Universität des Saarlandes, Gebäude 58, 66421 Homburg/Saar, Germany
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37
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Zhang S, Patel HH, Murray F, Remillard CV, Schach C, Thistlethwaite PA, Insel PA, Yuan JXJ. Pulmonary artery smooth muscle cells from normal subjects and IPAH patients show divergent cAMP-mediated effects on TRPC expression and capacitative Ca2+ entry. Am J Physiol Lung Cell Mol Physiol 2006; 292:L1202-10. [PMID: 17189322 DOI: 10.1152/ajplung.00214.2006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pulmonary vascular remodeling due to overgrowth of pulmonary artery smooth muscle cells (PASMC) is a major cause for the elevated vascular resistance in patients with idiopathic pulmonary arterial hypertension (IPAH). Increased cytosolic Ca(2+) concentration, resulting from enhanced capacitative Ca(2+) entry (CCE) and upregulated transient receptor potential (TRP) channel expression, is involved in stimulating PASMC proliferation. The current study was designed to determine the impact of cAMP, a second messenger that we hypothesized would blunt aspects of PASMC activity, as a possible contributor to IPAH pathophysiology. Short-term (30 min) pretreatment with forskolin (FSK; 10 muM), a direct activator of adenylyl cyclase, in combination with the cyclic nucleotide phosphodiesterase inhibitor isobutylmethylxanthine (IBMX; 200 muM), attenuated CCE in PASMC from normal subjects, patients without pulmonary hypertension (NPH), and patients with IPAH. The FSK-mediated CCE inhibition was independent of protein kinase A (PKA), because the PKA inhibitor H89 negligibly affected the decrease in CCE produced by cAMP. By contrast, longer (4 h) treatment with FSK (with IBMX) attenuated CCE in normal and NPH PASMC but enhanced CCE in IPAH PASMC. This enhancement of CCE was abolished by PKA inhibition and associated with an upregulation of TRPC3. In addition, cAMP increased TRPC1 mRNA expression in IPAH (but not in normal or NPH) PASMC, an effect blunted by H89. Furthermore, iloprost, a prostacyclin analog that increases cAMP, downregulated TRPC3 expression in IPAH PASMC and FSK-mediated cAMP increase inhibited IPAH PASMC proliferation. Although a rapid rise in cellular cAMP decreases CCE by a PKA-independent mechanism, sustained cAMP increase inhibits CCE in normal and NPH PASMC but increases CCE via a PKA-dependent pathway in IPAH PASMC. The divergent effect of cAMP on CCE parallels effects on TRPC expression. The results suggest that the combined use of a PKA inhibitor and cAMP-elevating drugs may provide a novel approach for treatment of IPAH.
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Affiliation(s)
- Shen Zhang
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093-0725, USA
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38
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Rojas H, Colina C, Ramos M, Benaim G, Jaffe EH, Caputo C, DiPolo R. Na+ entry via glutamate transporter activates the reverse Na+/Ca2+ exchange and triggers -induced Ca2+ release in rat cerebellar Type-1 astrocytes. J Neurochem 2006; 100:1188-202. [PMID: 17316398 DOI: 10.1111/j.1471-4159.2006.04303.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have previously demonstrated that rat cerebellar Type-1 astrocytes express a very active genistein sensitive Na(+)/Ca(2+) exchanger, which accounts for most of the total plasma membrane Ca(2+) fluxes and for the clearance of loads induced by physiological agonists. In this work, we have explored the mechanism by which the reverse Na(+)/Ca(2+) exchange is involved in agonist-induced Ca(2+) signaling in rat cerebellar astrocytes. Microspectrofluorometric measurements of Cai(2+) with Fluo-3 demonstrate that the Cai(2+) signals associated long (> 20 s) periods of reverse operation of the Na(+)/Ca(2+) exchange are amplified by a mechanism compatible with calcium-calcium release, while those associated with short (< 20 s) pulses are not amplified. This was confirmed by pharmacological experiments using ryanodine receptors agonist (4-chloro-m-cresol) and the endoplasmic reticulum ATPase inhibitor (thapsigargin). Confocal microscopy demonstrates a high co-localization of immunofluorescent labeled Na(+)/Ca(2+) exchanger and RyRs. Low (< 50 micromol/L) or high (> 500 micromol/L) concentrations of L-glutamate (L-Glu) or L-aspartate causes a rise in which is completely blocked by the Na(+)/Ca(2+) exchange inhibitors KB-R7943 and SEA0400. The most important novel finding presented in this work is that L-Glu activates the reverse mode of the Na(+)/Ca(2+) exchange by inducing Na(+) entry through the electrogenic Na(+)-Glu-co-transporter and not through the ionophoric L-Glu receptors, as confirmed by pharmacological experiments with specific blockers of the ionophoric L-Glu receptors and the electrogenic Glu transporter.
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Affiliation(s)
- Héctor Rojas
- Laboratorio de Fisiología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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Shimura M, Yasuda K, Nakzawa T, Kashiwagi K. The effect of unoprostone isopropyl on Ca2+ release-activated Ca2+ currents in cultured monkey trabecular meshwork cells and ciliary muscle cells. J Ocul Pharmacol Ther 2006; 22:219-26. [PMID: 16910861 DOI: 10.1089/jop.2006.22.219] [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: 11/12/2022] Open
Abstract
PURPOSE The aim of this study was to investigate the effect of unoprostone isopropyl (UF- 021) on Ca2+ release-activated Ca2+ (CRAC) currents in cultured monkey trabecular meshwork (TM) cells and to compare the inhibitory effects on CRAC in cultured monkey ciliary muscle (CM) cells. METHODS Both TM and CM cells were isolated from monkey eyes, and each was grown in monolayer cell cultures. To measure changes in intracellular Ca2+ concentrations ([Ca2+]i), both types of cells were labeled with fluo-3 acetoxymethylester (AM) as a calcium indicator for 30 min at 25 degrees C and imaged with a confocal laser scanning microscope. After depletion of the intracellular Ca2+ stores with 1 microM thapsigargin and 1 mM EGTA containing Ca2+-free external solution, exposure to 2 mM Ca2+-containing external solution induced a sudden increase in [Ca2+]i, which was defined as the CRAC current. RESULTS In both TM and CM cells, CRAC currents were observed and were well suppressed by unoprostone-free acid (M1 metabolite). In the TM cells, 3 microM M1 metabolite suppressed the CRAC current. In contrast, in the CM cells, the CRAC current was suppressed by 100 microM M1 metabolite, but not by 10 microM or less. The half maximal inhibition concentration of M1 metabolite was 24.8+/-9.8 microM in TM cells and 183+/-30.6 microM in CM cells. CONCLUSIONS These findings indicate that there are CRAC channels in both TM and CM cells, and the influx of [Ca2+]i through the CRAC channels is suppressed by M1 metabolite. The inhibitory effect of M1 metabolite on CRAC currents was more prominent in TM cells than in CM cells. Suppression of the Ca2+ influx through CRAC channels by M1 metabolite is thought to regulate muscle tone in TM and CM cells. Therefore, CRAC inhibition by M1 metabolite may contribute to reduction of intraocular pressure.
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Affiliation(s)
- Masahiko Shimura
- Department of Ophthalmology, NTT East Japan Tohoku Hospital, and Department of Ophthalmology and Medical Sciences, Tohoku University Graduate School of Medicine, Miyagi, Japan.
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40
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Yoshida T, Inoue R, Morii T, Takahashi N, Yamamoto S, Hara Y, Tominaga M, Shimizu S, Sato Y, Mori Y. Nitric oxide activates TRP channels by cysteine S-nitrosylation. Nat Chem Biol 2006; 2:596-607. [PMID: 16998480 DOI: 10.1038/nchembio821] [Citation(s) in RCA: 419] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Accepted: 08/04/2006] [Indexed: 02/06/2023]
Abstract
Transient receptor potential (TRP) proteins form plasma-membrane cation channels that act as sensors for diverse cellular stimuli. Here, we report a novel activation mechanism mediated by cysteine S-nitrosylation in TRP channels. Recombinant TRPC1, TRPC4, TRPC5, TRPV1, TRPV3 and TRPV4 of the TRPC and TRPV families, which are commonly classified as receptor-activated channels and thermosensor channels, induce entry of Ca(2+) into cells in response to nitric oxide (NO). Labeling and functional assays using cysteine mutants, together with membrane sidedness in activating reactive disulfides, show that cytoplasmically accessible Cys553 and nearby Cys558 are nitrosylation sites mediating NO sensitivity in TRPC5. The responsive TRP proteins have conserved cysteines on the same N-terminal side of the pore region. Notably, nitrosylation of native TRPC5 upon G protein-coupled ATP receptor stimulation elicits entry of Ca(2+) into endothelial cells. These findings reveal the structural motif for the NO-sensitive activation gate in TRP channels and indicate that NO sensors are a new functional category of cellular receptors extending over different TRP families.
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Affiliation(s)
- Takashi Yoshida
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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41
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Lanner JT, Katz A, Tavi P, Sandström ME, Zhang SJ, Wretman C, James S, Fauconnier J, Lännergren J, Bruton JD, Westerblad H. The role of Ca2+ influx for insulin-mediated glucose uptake in skeletal muscle. Diabetes 2006; 55:2077-83. [PMID: 16804078 DOI: 10.2337/db05-1613] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The involvement of Ca(2+) in insulin-mediated glucose uptake is uncertain. We measured Ca(2+) influx (as Mn(2+) quenching or Ba(2+) influx) and 2-deoxyglucose (2-DG) uptake in single muscle fibers isolated from limbs of adult mice; 2-DG uptake was also measured in isolated whole muscles. Exposure to insulin increased the Ca(2+) influx in single muscle cells. Ca(2+) influx in the presence of insulin was decreased by 2-aminoethoxydiphenyl borate (2-APB) and increased by the membrane-permeable diacylglycerol analog 1-oleyl-2-acetyl-sn-glycerol (OAG), agents frequently used to block and activate, respectively, nonselective cation channels. Maneuvers that decreased Ca(2+) influx in the presence of insulin also decreased 2-DG uptake, whereas increased Ca(2+) influx was associated with increased insulin-mediated glucose uptake in isolated single cells and whole muscles from both normal and insulin-resistant obese ob/ob mice. 2-APB and OAG affected neither basal nor hypoxia- or contraction-mediated 2-DG uptake. 2-APB did not inhibit the insulin-mediated activation of protein kinase B or extracellular signal-related kinase 1/2 in whole muscles. In conclusion, alterations in Ca(2+) influx specifically modulate insulin-mediated glucose uptake in both normal and insulin-resistant skeletal muscle. Moreover, the present results indicate that Ca(2+) acts late in the insulin signaling pathway, for instance, in the GLUT4 translocation to the plasma membrane.
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Affiliation(s)
- Johanna T Lanner
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
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Ratz PH, Berg KM. 2-Aminoethoxydiphenyl borate inhibits KCl-induced vascular smooth muscle contraction. Eur J Pharmacol 2006; 541:177-83. [PMID: 16765942 DOI: 10.1016/j.ejphar.2006.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 05/03/2006] [Accepted: 05/10/2006] [Indexed: 11/23/2022]
Abstract
K(+)-depolarization (KCl)-activated Ca(2+) entry permitting sustained force-maintenance in tonic vascular smooth muscle has long been attributed solely to activation of L-type voltage-operated Ca(2+) channels (VOCs). We used the transient receptor potential channel (TRP) blocker, 2-aminoethoxydiphenyl borate (2-APB), to test the hypothesis that KCl activates additional Ca(2+) entry pathways. 2-APB alone caused a transient weak increase in force, a sustained weak increase in basal [Ca(2+)](i) and myosin light chain phosphorylation, and inhibition of KCl-induced force, [Ca(2+)](i) and myosin light chain phosphorylation. 2-APB did not appear to block VOCs, because 2-APB did not inhibit 30 nM Bay k 8644-induced increases in [Ca(2+)](i). Moreover, although 1 microM nifedipine abolished the increase in [Ca(2+)](i) produced by alpha-adrenergic receptor activation, 2-APB produced an additional reduction in [Ca(2+)](i) below the basal level. These data support the conclusion that membrane depolarization activates 2-APB-sensitive TRPs in addition to VOCs to permit strong force-maintenance in tonic vascular smooth muscle.
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Affiliation(s)
- Paul H Ratz
- Department of Biochemistry, Virginia Commonwealth University, School of Medicine, Richmond, 23298-0614, USA.
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Chvanov M, Gerasimenko OV, Petersen OH, Tepikin AV. Calcium-dependent release of NO from intracellular S-nitrosothiols. EMBO J 2006; 25:3024-32. [PMID: 16810320 PMCID: PMC1500983 DOI: 10.1038/sj.emboj.7601207] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 05/30/2006] [Indexed: 11/08/2022] Open
Abstract
The paper describes a novel cellular mechanism for rapid calcium-dependent nitric oxide (NO) release. This release occurs due to NO liberation from S-nitrosothiols. We have analysed the changes of NO concentration in acutely isolated pancreatic acinar cells. Supramaximal acetylcholine (ACh) stimulation induced a Ca(2+)-dependent increase in the fluorescence in the majority of cells loaded with the NO probe DAF-FM via a patch pipette. The ACh-induced NO signals were insensitive to inhibitors of calmodulin and protein kinase C but were inhibited by calpain antagonists. The initial part of the NO signals induced by 10 muM ACh showed little sensitivity to inhibition of NO synthase (NOS); however, cell pretreatment with NO donors (increasing cellular S-nitrosothiol contents) substantially enhanced the initial component of NO responses. Pancreatic acinar cells were able to generate fast calcium-dependent NO responses when stimulated with physiological or supramaximal doses of secretagogues. Importantly, the source of this NO is the already available S-nitrosothiol store rather than de novo synthesis by NOS. A similar mechanism of NO release was found in dorsal root ganglia neurons.
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Affiliation(s)
- Michael Chvanov
- The Physiological Laboratory, The University of Liverpool, Liverpool, UK
- Department of Physiology, The University of Liverpool, Crown Street, PO Box 147, Liverpool L69 3BX, UK. Tel.: +44 151 794 5351; Fax: +44 151 794 5327; E-mail:
| | - Oleg V Gerasimenko
- The Physiological Laboratory, The University of Liverpool, Liverpool, UK
| | - Ole H Petersen
- The Physiological Laboratory, The University of Liverpool, Liverpool, UK
| | - Alexei V Tepikin
- The Physiological Laboratory, The University of Liverpool, Liverpool, UK
- Department of Physiology, The University of Liverpool, Crown Street, PO Box 147, Liverpool L69 3BX, UK. Tel.: +44 151 794 5351; Fax: +44 151 794 5327; E-mail:
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Chvanov M, Petersen OH, Tepikin A. Free radicals and the pancreatic acinar cells: role in physiology and pathology. Philos Trans R Soc Lond B Biol Sci 2006; 360:2273-84. [PMID: 16321797 PMCID: PMC1569596 DOI: 10.1098/rstb.2005.1757] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Reactive oxygen and nitrogen species (ROS and RNS) play an important role in signal transduction and cell injury processes. Nitric oxide synthase (NOS)-the key enzyme producing nitric oxide (NO)-is found in neuronal structures, vascular endothelium and, possibly, in acinar and ductal epithelial cells in the pancreas. NO is known to regulate cell homeostasis, and its effects on the acinar cells are reviewed here. ROS are implicated in the early events within the acinar cells, leading to the development of acute pancreatitis. The available data on ROS/RNS involvement in the apoptotic and necrotic death of pancreatic acinar cells will be discussed.
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Affiliation(s)
- M Chvanov
- The University of Liverpool The Physiological Laboratory Crown Street, Liverpool L69 3BX, UK.
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45
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Oestreich J, Dembrow NC, George AA, Zakon HH. A "sample-and-hold" pulse-counting integrator as a mechanism for graded memory underlying sensorimotor adaptation. Neuron 2006; 49:577-88. [PMID: 16476666 DOI: 10.1016/j.neuron.2006.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 12/05/2005] [Accepted: 01/29/2006] [Indexed: 11/19/2022]
Abstract
The mechanisms behind the induction of cellular correlates of memory by sensory input and their contribution to meaningful behavioral changes are largely unknown. We previously reported a graded memory in the form of sensorimotor adaptation in the electromotor output of electric fish. Here we show that the mechanism for this adaptation is a synaptically induced long-lasting shift in intrinsic neuronal excitability. This mechanism rapidly integrates hundreds of spikes in a second, or gradually integrates the same number of spikes delivered over tens of minutes. Thus, this mechanism appears immune to frequency-dependent fluctuations in input and operates as a simple pulse counter over a wide range of time scales, enabling it to transduce graded sensory information into a graded memory and a corresponding change in the behavioral output. This adaptation is based on an NMDA receptor-mediated change in intrinsic excitability of the postsynaptic neurons involving the Ca2+-dependent activation of TRP channels.
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Affiliation(s)
- Jörg Oestreich
- Section of Neurobiology, The University of Texas at Austin, 1 University Station C0920, Austin, Texas 78712, USA
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Amano T, Aoki S, Setsuie R, Sakurai M, Wada K, Noda M. Identification of a novel regulatory mechanism for norepinephrine transporter activity by the IP3 receptor. Eur J Pharmacol 2006; 536:62-8. [PMID: 16554048 DOI: 10.1016/j.ejphar.2006.02.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 01/27/2006] [Accepted: 02/21/2006] [Indexed: 10/25/2022]
Abstract
The norepinephrine transporter (NET) plays a crucial role in noradrenergic neurotransmission and is a target of many antidepressants and psychostimulants. Intracellular Ca2+ is reportedly involved in regulating NET activity, but the detailed mechanism is not clear. We employed a norepinephrine uptake assay using SH-SY5Y cells and found that the IP3 receptor inhibitors, 2-aminoethoxydiphenyl borate and xestospongin C, reduced the NET Vmax. These reductions were accompanied by the decreased cell surface expression of NET. Our findings suggest that intracellular Ca2+ mobilized by IP3 receptor is required for the maintenance of NET activity. This adds another pathway involving Ca2+ for the regulation of NET to other known mechanisms providing intracellular Ca2+.
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Affiliation(s)
- Taiju Amano
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Cima RR, Dubach JM, Wieland AM, Walsh BM, Soybel DI. Intracellular Ca(2+) and Zn(2+) signals during monochloramine-induced oxidative stress in isolated rat colon crypts. Am J Physiol Gastrointest Liver Physiol 2006; 290:G250-61. [PMID: 16002562 DOI: 10.1152/ajpgi.00501.2004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
During acute exacerbations of inflammatory bowel diseases, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the colon mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH(2)Cl), to serve as agonists of Ca(2+) and Zn(2+) accumulation within the colonocyte. Individual colon crypts prepared from Sprague-Dawley rats were mounted in perfusion chambers after loading with fluorescent reporters fura 2-AM and fluozin 3-AM. These reporters were characterized, in situ, for responsiveness to Ca(2+) and Zn(2+) in the cytoplasm. Responses to different concentrations of NH(2)Cl (50, 100, and 200 microM) were monitored. Subsequent studies were designed to identify the sources and mechanisms of NH(2)Cl-induced increases in Ca(2+) and Zn(2+) in the cytoplasm. Exposure to NH(2)Cl led to dose-dependent increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) in the range of 200-400 nM above baseline levels. Further studies indicated that NH(2)Cl-induced accumulation of Ca(2+) in the cytoplasm is the result of release from intracellular stores and basolateral entry of extracellular Ca(2+) through store-operated channels. In addition, exposure to NH(2)Cl resulted in dose-dependent and sustained increases in intracellular Zn(2+) concentration ([Zn(2+)](i)) in the nanomolar range. These alterations were neutralized by dithiothreitol, which shields intracellular thiol groups from oxidation. We conclude that Ca(2+)- and Zn(2+)-handling proteins are susceptible to oxidation by chloramines, leading to sustained, but not necessarily toxic, increases in [Ca(2+)](i) and [Zn(2+)](i). Under certain conditions, NH(2)Cl may act not as a toxin but as an agent that activates intracellular signaling pathways.
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Affiliation(s)
- Robert R Cima
- Department of Surgery, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA
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Dobrydneva Y, Abelt CJ, Dovel B, Thadigiri CM, Williams RL, Blackmore PF. 2-Aminoethoxydiphenyl Borate as a Prototype Drug for a Group of Structurally Related Calcium Channel Blockers in Human Platelets. Mol Pharmacol 2005; 69:247-56. [PMID: 16214957 DOI: 10.1124/mol.105.015701] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have synthesized a series of 2-aminoethoxydiphenyl borate (2-APB, 2,2-diphenyl-1,3,2-oxazaborolidine) analogs and tested their ability to inhibit thrombin-induced Ca(2+) influx in human platelets. The analogs were either synthesized by adding various substituents to the oxazaborolidine ring (methyl, dimethyl, tert-butyl, phenyl, methyl phenyl, and pyridyl) or increasing the size of the oxazaborolidine ring to seven- and nine-membered rings. NMR analysis of the boron-containing analogs suggests that each of them exist as a ring structure through the formation of an N-->B coordinate bond (except for the hexyl analog). The possibility that these boron-containing compounds formed dimers was also considered. All compounds dose-dependently inhibited thrombin-induced Ca(2+) influx in human platelets, with the 2,2-diphenyl-1,3,2-oxazaborolidine-5-one derivative having the weakest activity at 100 microM, whereas the (S)-4-benzyl and (R)-4-benzyl derivatives of 2-APB were approximately 10 times more potent than the parent 2-APB. Two nonboron analogs (3-methyl and 3-tert-butyl 2,2-diphenyl-1,3-oxazolidine) were synthesized; they had approximately the same activity as 2-APB, and this implies that the presence of boron was not necessary for inhibitory activity. All of the compounds tested were also able to inhibit thrombin-induced calcium release. We concluded that extensive modifications of the oxazaborolidine ring in 2-APB can be made, and Ca(2+)-blocking activity was maintained.
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Affiliation(s)
- Yuliya Dobrydneva
- Department of Physiological Sciences, Eastern Virginia Medical School, P.O. Box 1980, Norfolk, VA 23501, USA
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Yang H, Mergler S, Sun X, Wang Z, Lu L, Bonanno JA, Pleyer U, Reinach PS. TRPC4 knockdown suppresses epidermal growth factor-induced store-operated channel activation and growth in human corneal epithelial cells. J Biol Chem 2005; 280:32230-7. [PMID: 16033767 PMCID: PMC4096720 DOI: 10.1074/jbc.m504553200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Epidermal growth factor (EGF) in corneal epithelial cells stimulates proliferation by inducing capacitative calcium entry (CCE). However, neither the identity nor the mechanism of activation of the plasma membrane influx pathway that mediates CCE is known. Accordingly, we determined, in human corneal epithelial cells, whether or not (i) CCE is dependent upon stimulation of storeoperated channel (SOC) activity, (ii) the canonical transient receptor potential (TRP) protein isoform TRPC4 is a component of such channels, and (iii) suppression of TRPC4 protein expression decreases EGF-induced stimulation of SOC activity and proliferation. The whole cell patch-clamp technique was used to monitor TRPC4-mediated stimulation of SOC activity following intracellular calcium store depletion and induction of CCE. TRPC4 small interfering RNA transfection suppressed TRPC4 protein expression. Reverse transcription-PCR and Western blot analysis were used to assess knockdown efficiency of mRNA and protein expression. [(3)H]Thymidine incorporation was used to evaluate EGF-in-duced mitogenesis. Ca(2+) transients were measured by single-cell fluorescence imaging. TRPC4 knockdown decreased mRNA and protein expression by 89 and 87%, respectively. In these cells, EGF-induced SOC activation elicited by intracellular calcium store depletion was obviated; 2) EGF-induced CCE fell by 76%; 3) EGF-induced stimulation of SOC activity was eliminated; and 4) EGF-induced increases in proliferation fell by 54%. Thus, TRPC4 is a component of SOC in human corneal epithelial cells whose activation by EGF is requisite for an optimum mitogenic response to this growth factor.
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Affiliation(s)
- Hua Yang
- College of Optometry, State University of New York, New York, New York 10036
| | - Stefan Mergler
- Eye Clinic, Charité University Medicine, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Xingcai Sun
- School of Optometry, Indiana University, Bloomington, Indiana 47405
| | - Zheng Wang
- College of Optometry, State University of New York, New York, New York 10036
| | - Luo Lu
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, California 90502
| | | | - Uwe Pleyer
- Eye Clinic, Charité University Medicine, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Peter S. Reinach
- College of Optometry, State University of New York, New York, New York 10036
- To whom correspondence should be addressed: College of Optometry, State University of New York, 33 West 42nd St., New York, NY 10036. Tel.: 212-780-5165; Fax: 212-780-5174;
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Wang JP, Tsai JJ, Chen YS, Hsu MF. Stimulation of intracellular Ca2+ elevation in neutrophils by thiol-oxidizing phenylarsine oxide. Biochem Pharmacol 2005; 69:1225-34. [PMID: 15794943 DOI: 10.1016/j.bcp.2005.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 01/26/2005] [Indexed: 11/24/2022]
Abstract
Phenylarsine oxide (PAO), a trivalent arsenical compound, stimulated [Ca2+]i elevation in rat neutrophils in a Ca2+-containing medium but caused no appreciable response in a Ca2+-free medium. PAO also induced external Mn2+ entry, which was inhibited by N-acetyl-L-cysteine (NAC), but failed to elicit any appreciable Ba2+ and Sr2+ entry. Pretreatment of neutrophils with thiol-reducing agents including dithiothreitol (DTT), NAC, 2,3-dimercapto-1-propanol (DMP), 2,3-dimercaptopropane-1-sulfonic acid (DMPS) and tris-(2-carboxyethyl)phosphine (TCEP), all greatly inhibited PAO-induced [Ca2+]i elevation. Addition of Ni2+ or La3+ followed by PAO stimulation also attenuated the Ca2+ signals in a concentration-dependent manner. PAO had no significant effect on the production of reactive oxygen intermediates (ROI) and nitric oxide (NO) nor did it decrease cellular low molecular weight thiols levels. PAO-induced [Ca2+]i elevation was significantly inhibited by 1-[6-[17beta-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), the inhibitor of phospholipase C-coupled processes, genistein, a general tyrosine kinase inhibitor, phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, calyculin A, a cortical actin stabilizer, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY 294002), a phosphoinositide 3-kinase inhibitor, 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365), and cis-N-(2-phenylcyclopentyl)azacyclotridec-1-en-2-amine (MDL-12,330A), the blockers of receptor-gated and store-operated Ca2+ channels, whereas there was no appreciable effect exerted by aristolochic acid, a phospholipase A2 inhibitor, 7-nitroindazole and N-(3-aminomethyl)benzylacetamidine (1400W), the blockers of NO synthase, and by suspension in a Na+-deprived medium. In contrast, 2-aminoethoxydiphenyl borane (2-APB), the blocker of IP3 receptor and Ca2+ influx, enhanced the PAO-induced response. PAO had no effect on the plasma membrane Ca2+-ATPase (PMCA) activity in the pharmacological isolated neutrophil preparation and the neutrophil membrane fractions. These results indicate that PAO stimulates [Ca2+]i rise in rat neutrophils mainly through the oxidation of vicinal thiol groups on the cell surface membrane to activation of a non-store operated Ca2+ entry (non-SOCE) without affecting the activity of PMCA and the plasmalemmal Na+/Ca2+ exchanger.
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Affiliation(s)
- Jih-Pyang Wang
- Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan, ROC.
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