1
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Baron J, Groschner K, Tiapko O. Calcium transport and sensing in TRPC channels - New insights into a complex feedback regulation. Cell Calcium 2023; 116:102816. [PMID: 37897981 DOI: 10.1016/j.ceca.2023.102816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/30/2023]
Abstract
Canonical TRP (TRPC) channels are a still enigmatic family of signaling molecules with multimodal sensing features. These channels enable Ca2+ influx through the plasma membrane to control a diverse range of cellular functions. Based on both regulatory- and recently uncovered structural features, TRPC channels are considered to coordinate Ca2+ and other divalent cations not only within the permeation path but also at additional sensory sites. Analysis of TRPC structures by cryo-EM identified multiple regulatory ion binding pockets. With this review, we aim at an overview and a critical discussion of the current concepts of divalent sensing by TRPC channels.
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Affiliation(s)
- Jasmin Baron
- Gottfried-Schatz-Research-Center Medical Physics and Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/H03, 8010 Graz, Austria
| | - Klaus Groschner
- Gottfried-Schatz-Research-Center Medical Physics and Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/H03, 8010 Graz, Austria
| | - Oleksandra Tiapko
- Gottfried-Schatz-Research-Center Medical Physics and Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/H03, 8010 Graz, Austria.
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2
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Zong P, Li CX, Feng J, Cicchetti M, Yue L. TRP Channels in Stroke. Neurosci Bull 2023:10.1007/s12264-023-01151-5. [PMID: 37995056 DOI: 10.1007/s12264-023-01151-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/11/2023] [Indexed: 11/24/2023] Open
Abstract
Ischemic stroke is a devastating disease that affects millions of patients worldwide. Unfortunately, there are no effective medications for mitigating brain injury after ischemic stroke. TRP channels are evolutionally ancient biosensors that detect external stimuli as well as tissue or cellular injury. To date, many members of the TRP superfamily have been reported to contribute to ischemic brain injury, including the TRPC subfamily (1, 3, 4, 5, 6, 7), TRPV subfamily (1, 2, 3, 4) and TRPM subfamily (2, 4, 7). These TRP channels share structural similarities but have distinct channel functions and properties. Their activation during ischemic stroke can be beneficial, detrimental, or even both. In this review, we focus on discussing the interesting features of stroke-related TRP channels and summarizing the underlying cellular and molecular mechanisms responsible for their involvement in ischemic brain injury.
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Affiliation(s)
- Pengyu Zong
- Department of Cell Biology, Calhoun Cardiology Center, School of Medicine (UConn Health), University of Connecticut, Farmington, CT, 06030, USA.
- Institute for the Brain and Cognitive Sciences, University of Connecticut, 337 Mansfield Road, Unit 1272, Storrs, CT, 06269, USA.
| | - Cindy X Li
- Department of Cell Biology, Calhoun Cardiology Center, School of Medicine (UConn Health), University of Connecticut, Farmington, CT, 06030, USA
| | - Jianlin Feng
- Department of Cell Biology, Calhoun Cardiology Center, School of Medicine (UConn Health), University of Connecticut, Farmington, CT, 06030, USA
| | - Mara Cicchetti
- Department of Cell Biology, Calhoun Cardiology Center, School of Medicine (UConn Health), University of Connecticut, Farmington, CT, 06030, USA
- Department of Neuroscience, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA, 15260, USA
| | - Lixia Yue
- Department of Cell Biology, Calhoun Cardiology Center, School of Medicine (UConn Health), University of Connecticut, Farmington, CT, 06030, USA.
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3
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Wijerathne T, Lin WY, Cooray A, Muallem S, Lee KP. Hydrophobic interactions within the C terminus pole helices tunnel regulate calcium-dependent inactivation of TRPC3 in a calmodulin-dependent manner. Cell Calcium 2023; 109:102684. [PMID: 36495796 PMCID: PMC9875215 DOI: 10.1016/j.ceca.2022.102684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022]
Abstract
Recent structural studies have shown that the carboxyl-terminus of many TRP channels, including TRPC3, are folded into a horizontal rib helix that is connected to the vertical pole helix, which play roles in inter-structural interactions and multimerization. In a previous work we identified I807 located in the pole helix with a role in regulation of TRPC3 by STIM1 (Lee et al., 2014, Liu et al., 2022). To further determine the role of the pole helix in TRPC3 function, here we identified key hydrophobic residues in the pole helix that form tight tunnel-like structure and used mutations to probe their role in TRPC3 regulation by Ca2+ and Calmodulin. Our findings suggest that the hydrophobic starch formed by the I807-L818 residues has several roles, it modulates gating of TRPC3 by Ca2+, affects channel selectivity and the channel Ca2+ permeability. Mutations of I807, I811, L814 and L818 all attenuated the Ca2+-dependent inactivation (CDI) of TRPC3, with I807 having the most prominent effect. The extent of modulation of the CDI depended on the degree of hydrophobicity of I807. Moreover, the TRPC3(I807S) mutant showed altered channel monovalent ion selectivity and increased Ca2+ permeability, without affecting the channel permeability to Mg2+ and Ba2+ and without changing the pore diameter. The CDI of TRPC3 was reduced by an inactive calmodulin mutant and by a pharmacological inhibitor of calmodulin, which was eliminated by the I807S mutation. Notably, deletion of STIM1 caused similar alteration of TRPC3 properties. Taken together, these findings reveal a role of the pole helix in CDI, in addition to its potential role in channel multimerization that required gating of TRPC3 by STIM1. Since all TRPC and most TRP channels have pole helix structures, our findings raise the possibility that the pole helix may have similar roles in all the TRP family.
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Affiliation(s)
- Tharaka Wijerathne
- Laboratory of Physiology, College of Veterinary Medicine, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea
| | - Wei-Yin Lin
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Akila Cooray
- Laboratory of Physiology, College of Veterinary Medicine, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
| | - Kyu Pil Lee
- Laboratory of Physiology, College of Veterinary Medicine, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea.
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4
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Kollewe A, Schwarz Y, Oleinikov K, Raza A, Haupt A, Wartenberg P, Wyatt A, Boehm U, Ectors F, Bildl W, Zolles G, Schulte U, Bruns D, Flockerzi V, Fakler B. Subunit composition, molecular environment, and activation of native TRPC channels encoded by their interactomes. Neuron 2022; 110:4162-4175.e7. [PMID: 36257322 DOI: 10.1016/j.neuron.2022.09.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/15/2022] [Accepted: 09/23/2022] [Indexed: 12/24/2022]
Abstract
In the mammalian brain TRPC channels, a family of Ca2+-permeable cation channels, are involved in a variety of processes from neuronal growth and synapse formation to transmitter release, synaptic transmission and plasticity. The molecular appearance and operation of native TRPC channels, however, remained poorly understood. Here, we used high-resolution proteomics to show that TRPC channels in the rodent brain are macro-molecular complexes of more than 1 MDa in size that result from the co-assembly of the tetrameric channel core with an ensemble of interacting proteins (interactome). The core(s) of TRPC1-, C4-, and C5-containing channels are mostly heteromers with defined stoichiometries for each subtype, whereas TRPC3, C6, and C7 preferentially form homomers. In addition, TRPC1/C4/C5 channels may co-assemble with the metabotropic glutamate receptor mGluR1, thus guaranteeing both specificity and reliability of channel activation via the phospholipase-Ca2+ pathway. Our results unveil the subunit composition of native TRPC channels and resolve the molecular details underlying their activation.
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Affiliation(s)
- Astrid Kollewe
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Yvonne Schwarz
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Katharina Oleinikov
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Ahsan Raza
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Alexander Haupt
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Philipp Wartenberg
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Amanda Wyatt
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Ulrich Boehm
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Fabien Ectors
- Transgenic facility, FARAH Research Center, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
| | - Wolfgang Bildl
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Gerd Zolles
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, Schänzlestr. 18, 79104 Freiburg, Germany
| | - Dieter Bruns
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany.
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, Schänzlestr. 18, 79104 Freiburg, Germany; Center for Basics in NeuroModulation, Breisacherstr. 4, 79106 Freiburg, Germany.
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5
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Feng Y, Borosha S, Ratri A, Lee EB, Wang H, Fields TA, Kinsey WH, Vivian JL, Rumi MAK, Fields PE. DOT1L Methyltransferase Regulates Calcium Influx in Erythroid Progenitor Cells in Response to Erythropoietin. Int J Mol Sci 2022; 23:5137. [PMID: 35563527 PMCID: PMC9099724 DOI: 10.3390/ijms23095137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/02/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023] Open
Abstract
Erythropoietin (EPO) signaling plays a vital role in erythropoiesis by regulating proliferation and lineage-specific differentiation of murine hematopoietic progenitor cells (HPCs). An important downstream response of EPO signaling is calcium (Ca2+) influx, which is regulated by transient receptor potential channel (TRPC) proteins, particularly TRPC2 and TRPC6. While EPO induces Ca2+ influx through TRPC2, TRPC6 inhibits the function of TRPC2. Thus, interactions between TRPC2 and TRPC6 regulate the rate of Ca2+ influx in EPO-induced erythropoiesis. In this study, we observed that the expression of TRPC6 in KIT-positive erythroid progenitor cells was regulated by DOT1L. DOT1L is a methyltransferase that plays an important role in many biological processes during embryonic development including early erythropoiesis. We previously reported that Dot1l knockout (Dot1lKO) HPCs in the yolk sac failed to develop properly, which resulted in lethal anemia. In this study, we detected a marked downregulation of Trpc6 gene expression in Dot1lKO progenitor cells in the yolk sac compared to the wild type (WT). The promoter and the proximal regions of the Trpc6 gene locus exhibited an enrichment of H3K79 methylation, which is mediated solely by DOT1L. However, the expression of Trpc2, the positive regulator of Ca2+ influx, remained unchanged, resulting in an increased TRPC2/TRPC6 ratio. As the loss of DOT1L decreased TRPC6, which inhibited Ca2+ influx by TRPC2, Dot1lKO HPCs in the yolk sac exhibited accelerated and sustained elevated levels of Ca2+ influx. Such heightened Ca2+ levels might have detrimental effects on the growth and proliferation of HPCs in response to EPO.
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Affiliation(s)
- Yi Feng
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - Shaon Borosha
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - Anamika Ratri
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - Eun Bee Lee
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - Huizhen Wang
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (H.W.); (W.H.K.)
| | - Timothy A. Fields
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - William H. Kinsey
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (H.W.); (W.H.K.)
| | - Jay L. Vivian
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - M. A. Karim Rumi
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
| | - Patrick E. Fields
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA; (Y.F.); (S.B.); (A.R.); (E.B.L.); (T.A.F.); (J.L.V.); (M.A.K.R.)
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6
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Hu F, Cao X, Niu C, Wang K. Co-assembly of warm-temperature sensitive TRPV3 and TRPV4 channel complexes with distinct functional properties. Mol Pharmacol 2022; 101:390-399. [PMID: 35361697 DOI: 10.1124/molpharm.121.000370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 03/17/2022] [Indexed: 11/22/2022] Open
Abstract
Heteromeric assembly of temperature-sensitive TRP ion channels has been suggested to underlie the molecular basis of fine-tuning of temperature detection and chemical sensation. However, whether warmth-temperature sensitive TRPV3 and TRPV4 channels robustly expressed in the skin can form heteromeric assembly remains largely unknown. In this study, we show that TRPV3 and TRPV4 channels can co-assemble into functional heterotetrameric channels with distinct properties. Confocal imaging reveals a co-localization and association of TRPV3 and TRPV4 proteins in cell membrane. Co-immunoprecipitation analysis demonstrates a strong protein-protein interaction between TRPV3 and TRPV4 subunits from heterogeneously expressed cells or mouse skin tissues through their C-termini, but not in TRPV3 knockout tissues. Co-expression of TRPV3 and TRPV4 channels yields a heterotetrameric channel complexes characterized by an intermediate single-channel conductance, distinct activation threshold and pharmacology. Taken together, our findings demonstrate a heterotetrameric assembly of TRPV3 and TRPV4 channels, which may help explain the role of temperature-sensitive TRPV channels in fine-tuning of environmental detection and sensation in the skin. Significance Statement The co-assembly of TRPV3 and TRPV4 channel complexes increases the functional diversity within the channel subfamily, which may serve as a molecular basis for fine-tuning of environmental detection and temperature sensation in mammals.
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7
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Structural mechanism of human TRPC3 and TRPC6 channel regulation by their intracellular calcium-binding sites. Neuron 2022; 110:1023-1035.e5. [PMID: 35051376 DOI: 10.1016/j.neuron.2021.12.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/09/2021] [Accepted: 12/15/2021] [Indexed: 12/14/2022]
Abstract
TRPC3 and TRPC6 channels are calcium-permeable non-selective cation channels that are involved in many physiological processes. The gain-of-function (GOF) mutations of TRPC6 lead to familial focal segmental glomerulosclerosis (FSGS) in humans, but their pathogenic mechanism remains elusive. Here, we report the cryo-EM structures of human TRPC3 in both high-calcium and low-calcium conditions. Based on these structures and accompanying electrophysiological studies, we identified both inhibitory and activating calcium-binding sites in TRPC3 that couple intracellular calcium concentrations to the basal channel activity. These calcium sensors are also structurally and functionally conserved in TRPC6. We uncovered that the GOF mutations of TRPC6 activate the channel by allosterically abolishing the inhibitory effects of intracellular calcium. Furthermore, structures of human TRPC6 in complex with two chemically distinct inhibitors bound at different ligand-binding pockets reveal different conformations of the transmembrane domain, providing templates for further structure-based drug design targeting TRPC6-related diseases such as FSGS.
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8
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Saldías MP, Maureira D, Orellana-Serradell O, Silva I, Lavanderos B, Cruz P, Torres C, Cáceres M, Cerda O. TRP Channels Interactome as a Novel Therapeutic Target in Breast Cancer. Front Oncol 2021; 11:621614. [PMID: 34178620 PMCID: PMC8222984 DOI: 10.3389/fonc.2021.621614] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/31/2021] [Indexed: 12/14/2022] Open
Abstract
Breast cancer is one of the most frequent cancer types worldwide and the first cause of cancer-related deaths in women. Although significant therapeutic advances have been achieved with drugs such as tamoxifen and trastuzumab, breast cancer still caused 627,000 deaths in 2018. Since cancer is a multifactorial disease, it has become necessary to develop new molecular therapies that can target several relevant cellular processes at once. Ion channels are versatile regulators of several physiological- and pathophysiological-related mechanisms, including cancer-relevant processes such as tumor progression, apoptosis inhibition, proliferation, migration, invasion, and chemoresistance. Ion channels are the main regulators of cellular functions, conducting ions selectively through a pore-forming structure located in the plasma membrane, protein–protein interactions one of their main regulatory mechanisms. Among the different ion channel families, the Transient Receptor Potential (TRP) family stands out in the context of breast cancer since several members have been proposed as prognostic markers in this pathology. However, only a few approaches exist to block their specific activity during tumoral progress. In this article, we describe several TRP channels that have been involved in breast cancer progress with a particular focus on their binding partners that have also been described as drivers of breast cancer progression. Here, we propose disrupting these interactions as attractive and potential new therapeutic targets for treating this neoplastic disease.
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Affiliation(s)
- María Paz Saldías
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Diego Maureira
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Octavio Orellana-Serradell
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Ian Silva
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Boris Lavanderos
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Pablo Cruz
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Camila Torres
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile
| | - Mónica Cáceres
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile.,The Wound Repair, Treatment, and Health (WoRTH) Initiative, Santiago, Chile
| | - Oscar Cerda
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile.,The Wound Repair, Treatment, and Health (WoRTH) Initiative, Santiago, Chile
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9
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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10
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Coronas V, Terrié E, Déliot N, Arnault P, Constantin B. Calcium Channels in Adult Brain Neural Stem Cells and in Glioblastoma Stem Cells. Front Cell Neurosci 2020; 14:600018. [PMID: 33281564 PMCID: PMC7691577 DOI: 10.3389/fncel.2020.600018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
The brain of adult mammals, including humans, contains neural stem cells (NSCs) located within specific niches of which the ventricular-subventricular zone (V-SVZ) is the largest one. Under physiological conditions, NSCs proliferate, self-renew and produce new neurons and glial cells. Several recent studies established that oncogenic mutations in adult NSCs of the V-SVZ are responsible for the emergence of malignant primary brain tumors called glioblastoma. These aggressive tumors contain a small subpopulation of cells, the glioblastoma stem cells (GSCs), that are endowed with proliferative and self-renewal abilities like NSCs from which they may arise. GSCs are thus considered as the cells that initiate and sustain tumor growth and, because of their resistance to current treatments, provoke tumor relapse. A growing body of studies supports that Ca2+ signaling controls a variety of processes in NSCs and GSCs. Ca2+ is a ubiquitous second messenger whose fluctuations of its intracellular concentrations are handled by channels, pumps, exchangers, and Ca2+ binding proteins. The concerted action of the Ca2+ toolkit components encodes specific Ca2+ signals with defined spatio-temporal characteristics that determine the cellular responses. In this review, after a general overview of the adult brain NSCs and GSCs, we focus on the multiple roles of the Ca2+ toolkit in NSCs and discuss how GSCs hijack these mechanisms to promote tumor growth. Extensive knowledge of the role of the Ca2+ toolkit in the management of essential functions in healthy and pathological stem cells of the adult brain should help to identify promising targets for clinical applications.
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Affiliation(s)
- Valérie Coronas
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Elodie Terrié
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Nadine Déliot
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Patricia Arnault
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Bruno Constantin
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
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Bacsa B, Tiapko O, Stockner T, Groschner K. Mechanisms and significance of Ca 2+ entry through TRPC channels. CURRENT OPINION IN PHYSIOLOGY 2020; 17:25-33. [PMID: 33210055 PMCID: PMC7116371 DOI: 10.1016/j.cophys.2020.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The transient receptor potential (TRP) superfamily of plasma membrane cation channels has been recognized as a signaling hub in highly diverse settings of human physiopathology. In the past three decades of TRP research, attention was focused mainly on the channels Ca2+ signaling function, albeit additional cellular functions, aside of providing a Ca2+ entry pathway, have been identified. Our understanding of Ca2+ signaling by TRP proteins has recently been advanced by a gain in high-resolution structure information on these pore complexes, and by the development of novel tools to investigate their role in spatiotemporal Ca2+ handling. This review summarizes recent discoveries as well as remaining, unresolved aspects of the canonical subfamily of transient receptor potential channels (TRPC) research. We aim at a concise overview on current mechanistic concepts of Ca2+ entry through- and Ca2+ signaling by TRPC channels.
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Affiliation(s)
- Bernadett Bacsa
- Gottfried-Schatz-Research-Center - Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria
| | - Oleksandra Tiapko
- Gottfried-Schatz-Research-Center - Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr. 13A, 1090 Vienna, Austria
| | - Klaus Groschner
- Gottfried-Schatz-Research-Center - Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria
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12
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Sato A, Arichi S, Kojima F, Hayashi T, Ohba T, Cheung DL, Eto K, Narushima M, Murakoshi H, Maruo Y, Kadoya Y, Nabekura J, Ishibashi H. Histamine depolarizes rat intracardiac ganglion neurons through the activation of TRPC non-selective cation channels. Eur J Pharmacol 2020; 886:173536. [PMID: 32896550 DOI: 10.1016/j.ejphar.2020.173536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 08/27/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022]
Abstract
The cardiac plexus, which contains parasympathetic ganglia, plays an important role in regulating cardiac function. Histamine is known to excite intracardiac ganglion neurons, but the underlying mechanism is obscure. In the present study, therefore, the effect of histamine on rat intracardiac ganglion neurons was investigated using perforated patch-clamp recordings. Histamine depolarized acutely isolated neurons with a half-maximal effective concentration of 4.5 μM. This depolarization was markedly inhibited by the H1 receptor antagonist triprolidine and mimicked by the H1 receptor agonist 2-pyridylethylamine, thus implicating histamine H1 receptors. Consistently, reverse transcription-PCR (RT-PCR) and Western blot analyses confirmed H1 receptor expression in the intracardiac ganglia. Under voltage-clamp conditions, histamine evoked an inward current that was potentiated by extracellular Ca2+ removal and attenuated by extracellular Na+ replacement with N-methyl-D-glucamine. This implicated the involvement of non-selective cation channels, which given the link between H1 receptors and Gq/11-protein-phospholipase C signalling, were suspected to be transient receptor potential canonical (TRPC) channels. This was confirmed by the marked inhibition of the inward current through the pharmacological disruption of either Gq/11 signalling or intracellular Ca2+ release and by the application of the TRPC blockers Pyr3, Gd3+ and ML204. Consistently, RT-PCR analysis revealed the expression of several TRPC subtypes in the intracardiac ganglia. Whilst histamine was also separately found to inhibit the M-current, the histamine-induced depolarization was only significantly inhibited by the TRPC blockers Gd3+ and ML204, and not by the M-current blocker XE991. These results suggest that TRPC channels serve as the predominant mediator of neuronal excitation by histamine.
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Affiliation(s)
- Aya Sato
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan; Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan; Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Shiho Arichi
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Fumiaki Kojima
- Department of Pharmacology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Toru Hayashi
- Department of Anatomical Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tatsuko Ohba
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Dennis Lawrence Cheung
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Kei Eto
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Madoka Narushima
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Yuichi Kadoya
- Department of Anatomical Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Hitoshi Ishibashi
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan.
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13
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Wang H, Cheng X, Tian J, Xiao Y, Tian T, Xu F, Hong X, Zhu MX. TRPC channels: Structure, function, regulation and recent advances in small molecular probes. Pharmacol Ther 2020; 209:107497. [PMID: 32004513 DOI: 10.1016/j.pharmthera.2020.107497] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/14/2020] [Indexed: 02/08/2023]
Abstract
Transient receptor potential canonical (TRPC) channels constitute a group of receptor-operated calcium-permeable nonselective cation channels of the TRP superfamily. The seven mammalian TRPC members, which can be further divided into four subgroups (TRPC1, TRPC2, TRPC4/5, and TRPC3/6/7) based on their amino acid sequences and functional similarities, contribute to a broad spectrum of cellular functions and physiological roles. Studies have revealed complexity of their regulation involving several components of the phospholipase C pathway, Gi and Go proteins, and internal Ca2+ stores. Recent advances in cryogenic electron microscopy have provided several high-resolution structures of TRPC channels. Growing evidence demonstrates the involvement of TRPC channels in diseases, particularly the link between genetic mutations of TRPC6 and familial focal segmental glomerulosclerosis. Because TRPCs were discovered by the molecular identity first, their pharmacology had lagged behind. This is rapidly changing in recent years owning to great efforts from both academia and industry. A number of potent tool compounds from both synthetic and natural products that selective target different subtypes of TRPC channels have been discovered, including some preclinical drug candidates. This review will cover recent advancements in the understanding of TRPC channel regulation, structure, and discovery of novel TRPC small molecular probes over the past few years, with the goal of facilitating drug discovery for the study of TRPCs and therapeutic development.
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Affiliation(s)
- Hongbo Wang
- Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education; Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China.
| | - Xiaoding Cheng
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
| | - Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yuling Xiao
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
| | - Tian Tian
- Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China
| | - Fuchun Xu
- Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China
| | - Xuechuan Hong
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China.
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Post-Translational Modification and Natural Mutation of TRPC Channels. Cells 2020; 9:cells9010135. [PMID: 31936014 PMCID: PMC7016788 DOI: 10.3390/cells9010135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/03/2020] [Accepted: 01/03/2020] [Indexed: 02/06/2023] Open
Abstract
Transient Receptor Potential Canonical (TRPC) channels are homologues of Drosophila TRP channel first cloned in mammalian cells. TRPC family consists of seven members which are nonselective cation channels with a high Ca2+ permeability and are activated by a wide spectrum of stimuli. These channels are ubiquitously expressed in different tissues and organs in mammals and exert a variety of physiological functions. Post-translational modifications (PTMs) including phosphorylation, N-glycosylation, disulfide bond formation, ubiquitination, S-nitrosylation, S-glutathionylation, and acetylation play important roles in the modulation of channel gating, subcellular trafficking, protein-protein interaction, recycling, and protein architecture. PTMs also contribute to the polymodal activation of TRPCs and their subtle regulation in diverse physiological contexts and in pathological situations. Owing to their roles in the motor coordination and regulation of kidney podocyte structure, mutations of TRPCs have been implicated in diseases like cerebellar ataxia (moonwalker mice) and focal and segmental glomerulosclerosis (FSGS). The aim of this review is to comprehensively integrate all reported PTMs of TRPCs, to discuss their physiological/pathophysiological roles if available, and to summarize diseases linked to the natural mutations of TRPCs.
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15
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Polat OK, Uno M, Maruyama T, Tran HN, Imamura K, Wong CF, Sakaguchi R, Ariyoshi M, Itsuki K, Ichikawa J, Morii T, Shirakawa M, Inoue R, Asanuma K, Reiser J, Tochio H, Mori Y, Mori MX. Contribution of Coiled-Coil Assembly to Ca 2+/Calmodulin-Dependent Inactivation of TRPC6 Channel and its Impacts on FSGS-Associated Phenotypes. J Am Soc Nephrol 2019; 30:1587-1603. [PMID: 31266820 DOI: 10.1681/asn.2018070756] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 04/23/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND TRPC6 is a nonselective cation channel, and mutations of this gene are associated with FSGS. These mutations are associated with TRPC6 current amplitude amplification and/or delay of the channel inactivation (gain-of-function phenotype). However, the mechanism of the gain-of-function in TRPC6 activity has not yet been clearly solved. METHODS We performed electrophysiologic, biochemical, and biophysical experiments to elucidate the molecular mechanism underlying calmodulin (CaM)-mediated Ca2+-dependent inactivation (CDI) of TRPC6. To address the pathophysiologic contribution of CDI, we assessed the actin filament organization in cultured mouse podocytes. RESULTS Both lobes of CaM helped induce CDI. Moreover, CaM binding to the TRPC6 CaM-binding domain (CBD) was Ca2+-dependent and exhibited a 1:2 (CaM/CBD) stoichiometry. The TRPC6 coiled-coil assembly, which brought two CBDs into adequate proximity, was essential for CDI. Deletion of the coiled-coil slowed CDI of TRPC6, indicating that the coiled-coil assembly configures both lobes of CaM binding on two CBDs to induce normal CDI. The FSGS-associated TRPC6 mutations within the coiled-coil severely delayed CDI and often increased TRPC6 current amplitudes. In cultured mouse podocytes, FSGS-associated channels and CaM mutations led to sustained Ca2+ elevations and a disorganized cytoskeleton. CONCLUSIONS The gain-of-function mechanism found in FSGS-causing mutations in TRPC6 can be explained by impairments of the CDI, caused by disruptions of TRPC's coiled-coil assembly which is essential for CaM binding. The resulting excess Ca2+ may contribute to structural damage in the podocytes.
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Affiliation(s)
- Onur K Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Masatoshi Uno
- Department of Biophysics, Graduate School of Science.,Department of Molecular Engineering, Graduate School of Engineering
| | - Terukazu Maruyama
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Ha Nam Tran
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Department of Technology and Ecology, Laboratory of Environmental Systems Biology, Graduate School of Global Environmental Studies
| | - Kayo Imamura
- Department of Biophysics, Graduate School of Science
| | - Chee Fah Wong
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Department of Biology, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Perak, Malaysia
| | - Reiko Sakaguchi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan
| | - Mariko Ariyoshi
- Department of Molecular Engineering, Graduate School of Engineering
| | - Kyohei Itsuki
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Jun Ichikawa
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Takashi Morii
- Institute of Advanced Energy, Kyoto University, Kyoto, Japan
| | | | - Ryuji Inoue
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Katsuhiko Asanuma
- Department of Nephrology, School of Medicine, Chiba University, Chiba, Japan
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | | | - Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Masayuki X Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering,
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16
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TRPC3 Regulates the Proliferation and Apoptosis Resistance of Triple Negative Breast Cancer Cells through the TRPC3/RASA4/MAPK Pathway. Cancers (Basel) 2019; 11:cancers11040558. [PMID: 31003514 PMCID: PMC6520729 DOI: 10.3390/cancers11040558] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/13/2019] [Accepted: 04/16/2019] [Indexed: 12/30/2022] Open
Abstract
Currently, there is no effective molecular-based therapy for triple-negative breast cancer (TNBC). Canonical transient receptor potential isoform 3 (TRPC3) was previously shown to be upregulated in breast cancer biopsy tissues when compared to normal breast tissues. However, the biological role of TRPC3 in breast cancer still remains to be elucidated. In this study, subcellular fractionation followed by Western blot and immunocytochemistry showed that TRPC3 was over-expressed on the plasma membrane of TNBC line MDA-MB-231 when compared to an estrogen receptor-positive cell line MCF-7. TRPC3 blocker Pyr3 and dominant negative of TRPC3 attenuated proliferation, induced apoptosis and sensitized cell death to chemotherapeutic agents in MDA-MB-231 as measured by proliferation assays. Interestingly, Ras GTPase-activating protein 4 (RASA4), a Ca2+-promoted Ras-MAPK pathway suppressor, was found to be located on the plasma membrane of MDA-MB-231. Blocking TRPC3 decreased the amount of RASA4 located on the plasma membrane, with concomitant activation of MAPK pathways. Our results suggest that, in TNBC MDA-MB-231 cells, Ca2+ influx through TRPC3 channel sustains the presence of RASA4 on the plasma membrane where it inhibits the Ras-MAPK pathway, leading to proliferation and apoptosis resistance. Our study reveals the novel TRPC3-RASA4-MAPK signaling cascade in TNBC cells and suggests that TRPC3 may be exploited as a potential therapeutic target for TNBC.
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17
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Rubaiy HN. Treasure troves of pharmacological tools to study transient receptor potential canonical 1/4/5 channels. Br J Pharmacol 2019; 176:832-846. [PMID: 30656647 DOI: 10.1111/bph.14578] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/25/2018] [Accepted: 12/18/2018] [Indexed: 12/13/2022] Open
Abstract
Canonical or classical transient receptor potential 4 and 5 proteins (TRPC4 and TRPC5) assemble as homomers or heteromerize with TRPC1 protein to form functional nonselective cationic channels with high calcium permeability. These channel complexes, TRPC1/4/5, are widely expressed in nervous and cardiovascular systems, also in other human tissues and cell types. It is debatable that TRPC1 protein is able to form a functional ion channel on its own. A recent explosion of molecular information about TRPC1/4/5 has emerged including knowledge of their distribution, function, and regulation suggesting these three members of the TRPC subfamily of TRP channels play crucial roles in human physiology and pathology. Therefore, these ion channels represent potential drug targets for cancer, epilepsy, anxiety, pain, and cardiac remodelling. In recent years, a number of highly selective small-molecule modulators of TRPC1/4/5 channels have been identified as being potent with improved pharmacological properties. This review will focus on recent remarkable small-molecule agonists: (-)-englerin A and tonantzitlolone and antagonists: Pico145 and HC7090, of TPRC1/4/5 channels. In addition, this work highlights other recently identified modulators of these channels such as the benzothiadiazine derivative, riluzole, ML204, clemizole, and AC1903. Together, these treasure troves of agonists and antagonists of TRPC1/4/5 channels provide valuable hints to comprehend the functional importance of these ion channels in native cells and in vivo animal models. Importantly, human diseases and disorders mediated by these proteins can be studied using these compounds to perhaps initiate drug discovery efforts to develop novel therapeutic agents.
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Affiliation(s)
- Hussein N Rubaiy
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, UK
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18
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Tolstykh GP, Cantu JC, Tarango M, Ibey BL. Receptor- and store-operated mechanisms of calcium entry during the nanosecond electric pulse-induced cellular response. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:685-696. [PMID: 30552899 DOI: 10.1016/j.bbamem.2018.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 11/16/2022]
Abstract
Nanosecond electric pulses have been shown to open nanopores in the cell plasma membrane by fluorescent imaging of calcium uptake and fluorescent dyes, including propidium (Pr) iodide and YO-PRO-1 (YP1). Recently, we demonstrated that nsEPs also induce the phosphoinositide intracellular signaling cascade by phosphatidylinositol-4,5-bisphosphate (PIP2) depletion resulting in physiological responses similar to those observed following stimulation of Gq11-coupled receptors. In this paper, we explore the role of receptor- and store-operated calcium entry (ROCE/SOCE) mechanisms in the observed response of cells to nsEP. We show that addition of the ROCE/SOCE and transient receptor potential channel (TRPC) blocker gadolinium (Gd3+, 300 μM) slows PIP2 depletion following 1 and 20 nsEP exposures. Lipid rafts, regions of the plasma membrane rich in PIP2 and TRPC, are also disrupted by nsEP exposure suggesting that ROCE/SOCE mechanisms are likely impacted. Reducing the expression of stromal interaction molecule 1 (STIM1) protein, a key protein in ROCE and SOCE, in cells exposure to nsEP resulted in a reduction in induced intracellular calcium rise. Additionally, after exposure to 1 and 20 nsEPs (16.2 kV/cm, 5 Hz), intracellular calcium rises were significantly reduced by the addition of GD3+ and SKF-96365 (1-[2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl) propoxy] ethyl-1H-imidazole hydrochloride, 100 μM), a blocker of STIM1 interaction. However, using similar nsEP exposure parameters, SKF-96365 was less effective at reducing YP1 uptake compared to Gd3+. Thus, it is possible that SKF-96365 could block STIM1 interactions within the cell, while Gd3+ could acts on TRPC/nanopores from outside of the cell. Our results present evidence of nsEP induces ROCE and SOCE mechanisms and demonstrate that YP1 and Ca2+ cannot be used solely as markers of nsEP-induced nanoporation.
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Affiliation(s)
- Gleb P Tolstykh
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.
| | - Jody C Cantu
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Melissa Tarango
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
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Tiapko O, Groschner K. TRPC3 as a Target of Novel Therapeutic Interventions. Cells 2018; 7:cells7070083. [PMID: 30037143 PMCID: PMC6071100 DOI: 10.3390/cells7070083] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 01/25/2023] Open
Abstract
TRPC3 is one of the classical members of the mammalian transient receptor potential (TRP) superfamily of ion channels. TRPC3 is a molecule with intriguing sensory features including the direct recognition of and activation by diacylglycerols (DAG). Although TRPC3 channels are ubiquitously expressed, they appear to control functions of the cardiovascular system and the brain in a highly specific manner. Moreover, a role of TRPC3 in immunity, cancer, and tissue remodeling has been proposed, generating much interest in TRPC3 as a target for pharmacological intervention. Advances in the understanding of molecular architecture and structure-function relations of TRPC3 have been the foundations for novel therapeutic approaches, such as photopharmacology and optochemical genetics of TRPC3. This review provides an account of advances in therapeutic targeting of TRPC3 channels.
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Affiliation(s)
- Oleksandra Tiapko
- Gottfried-Schatz-Research-Center-Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria.
| | - Klaus Groschner
- Gottfried-Schatz-Research-Center-Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria.
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20
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Canonical Transient Receptor Potential Channel 3 Contributes to Febrile Seizure Inducing Neuronal Cell Death and Neuroinflammation. Cell Mol Neurobiol 2018; 38:1215-1226. [PMID: 29748835 DOI: 10.1007/s10571-018-0586-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 04/20/2018] [Indexed: 12/17/2022]
Abstract
Febrile seizure (FS) counts as the most common seizures symptom in children undergoing recurrent seizures, posing a high risk to developing subsequent temporal lobe epilepsy. Canonical transient receptor potential channel (TRPC) members are identified as the FS-related genes in hyperthermia prone rats. However, the role of TRPC3 in hyperthermia-induced FS rats remains unclear. In the present study, we investigated whether TRPC3 functionally contributes to the development of FSs. Elevated TRPC3 mRNA and protein levels was detected in hyperthermia-induced FS rats and rat hippocampal neuron cells. The specific inhibitor of TRPC3, Pyr3, remarkably attenuated the susceptibility and severity of seizures, neuronal cell death, and neuroinflammation in FS rats. Conversely, NCX3 activation was apparently suppressed in rats subjected to recurrent FS and rat hippocampal neuron cells. The expression of NCX3 was up-regulated after TRPC3 inhibition in vivo and in vitro. Furthermore, an interaction between TRPC3 and NCX3 was detected by co-immunoprecipitation. Inhibition of TRPC3 suppressed intracellular Ca2+ levels in hyperthermia-treated hippocampal neuronal cells. In conclusion, our findings supported that TRPC3 functions as a critical regulator of seizure susceptibility and targeting TRPC3 may be a new therapeutic strategy for FS.
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21
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Dutta Banik D, Martin LE, Freichel M, Torregrossa AM, Medler KF. TRPM4 and TRPM5 are both required for normal signaling in taste receptor cells. Proc Natl Acad Sci U S A 2018; 115:E772-E781. [PMID: 29311301 PMCID: PMC5789955 DOI: 10.1073/pnas.1718802115] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Peripheral taste receptor cells use multiple signaling pathways to transduce taste stimuli into output signals that are sent to the brain. Transient receptor potential melastatin 5 (TRPM5), a sodium-selective TRP channel, functions as a common downstream component in sweet, bitter, and umami signaling pathways. In the absence of TRPM5, mice have a reduced, but not abolished, ability to detect stimuli, suggesting that a TRPM5-independent pathway also contributes to these signals. Here, we identify a critical role for the sodium-selective TRP channel TRPM4 in taste transduction. Using live cell imaging and behavioral studies in KO mice, we show that TRPM4 and TRPM5 are both involved in taste-evoked signaling. Loss of either channel significantly impairs taste, and loss of both channels completely abolishes the ability to detect bitter, sweet, or umami stimuli. Thus, both TRPM4 and TRPM5 are required for transduction of taste stimuli.
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Affiliation(s)
| | - Laura E Martin
- Department of Psychology, University at Buffalo, Buffalo, NY 14260
| | - Marc Freichel
- Pharmakologisches Institut, Universität Heidelberg, D-69120 Heidelberg, Germany
| | | | - Kathryn F Medler
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260;
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22
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Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis. Sci Rep 2017; 7:16332. [PMID: 29180820 PMCID: PMC5703708 DOI: 10.1038/s41598-017-16689-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 11/15/2017] [Indexed: 12/19/2022] Open
Abstract
Subcutaneous white adipose tissue (scWAT) is the major fat depot in humans and is a central player in regulating whole body metabolism. Skin exposure to UV wavelengths from sunlight is required for Vitamin D synthesis and pigmentation, although it is plausible that longer visible wavelengths that penetrate the skin may regulate scWAT function. In this regard, we discovered a novel blue light-sensitive current in human scWAT that is mediated by melanopsin coupled to transient receptor potential canonical cation channels. This pathway is activated at physiological intensities of light that penetrate the skin on a sunny day. Daily exposure of differentiated adipocytes to blue light resulted in decreased lipid droplet size, increased basal lipolytic rate and alterations in adiponectin and leptin secretion. Our results suggest that scWAT function may be directly under the influence of ambient sunlight exposure and may have important implications for our current understanding of adipocyte biology. (150 words)
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Belkacemi T, Niermann A, Hofmann L, Wissenbach U, Birnbaumer L, Leidinger P, Backes C, Meese E, Keller A, Bai X, Scheller A, Kirchhoff F, Philipp SE, Weissgerber P, Flockerzi V, Beck A. TRPC1- and TRPC3-dependent Ca 2+ signaling in mouse cortical astrocytes affects injury-evoked astrogliosis in vivo. Glia 2017. [PMID: 28636132 DOI: 10.1002/glia.23180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Following brain injury astrocytes change into a reactive state, proliferate and grow into the site of lesion, a process called astrogliosis, initiated and regulated by changes in cytoplasmic Ca2+ . Transient receptor potential canonical (TRPC) channels may contribute to Ca2+ influx but their presence and possible function in astrocytes is not known. By RT-PCR and RNA sequencing we identified transcripts of Trpc1, Trpc2, Trpc3, and Trpc4 in FACS-sorted glutamate aspartate transporter (GLAST)-positive cultured mouse cortical astrocytes and subcloned full-length Trpc1 and Trpc3 cDNAs from these cells. Ca2+ entry in cortical astrocytes depended on TRPC3 and was increased in the absence of Trpc1. After co-expression of Trpc1 and Trpc3 in HEK-293 cells both proteins co-immunoprecipitate and form functional heteromeric channels, with TRPC1 reducing TRPC3 activity. In vitro, lack of Trpc3 reduced astrocyte proliferation and migration whereas the TRPC3 gain-of-function moonwalker mutation and Trpc1 deficiency increased astrocyte migration. In vivo, astrogliosis and cortex edema following stab wound injury were reduced in Trpc3-/- but increased in Trpc1-/- mice. In summary, our results show a decisive contribution of TRPC3 to astrocyte Ca2+ signaling, which is even augmented in the absence of Trpc1, in particular following brain injury. Targeted therapies to reduce TRPC3 channel activity in astrocytes might therefore be beneficial in traumatic brain injury.
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Affiliation(s)
- Thabet Belkacemi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Alexander Niermann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Laura Hofmann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Ulrich Wissenbach
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA.,Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, C1107AFF, Argentina
| | | | - Christina Backes
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Eckart Meese
- Institut für Humangenetik, Homburg, 66421, Germany
| | - Andreas Keller
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Xianshu Bai
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Anja Scheller
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Frank Kirchhoff
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Stephan E Philipp
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Petra Weissgerber
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany.,Zentrum für Human- und Molekularbiologie, Homburg, 66421, Germany
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Transient receptor potential canonical type 3 channels: Interactions, role and relevance - A vascular focus. Pharmacol Ther 2017; 174:79-96. [DOI: 10.1016/j.pharmthera.2017.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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25
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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: 212] [Impact Index Per Article: 30.3] [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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27
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Abstract
TRPC channels are the first identified members in the TRP family. They function as either homo- or heterotetramers regulating intracellular Ca2+ concentration in response to numerous physiological or pathological stimuli. TRPC channels are nonselective cation channels permeable to Ca2+. The properties and the functional domains of TRPC channels have been identified by electrophysiological and biochemical methods. However, due to the large size, instability, and flexibility of their complexes, the structures of the members in TRPC family remain unrevealed. More efforts should be made on structure analysis and generating good tools, including specific antibodies, agonist, and antagonist.
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Affiliation(s)
- Shengjie Feng
- Department of Physiology, University of California, San Francisco, CA, USA.
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28
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Ku CY, Babich L, Word RA, Zhong M, Ulloa A, Monga M, Sanborn BM. Expression of Transient Receptor Channel Proteins in Human Fundal Myometrium in Pregnancy. ACTA ACUST UNITED AC 2016; 13:217-25. [PMID: 16527499 DOI: 10.1016/j.jsgi.2005.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Cation channels comprised of transient receptor potential (TrpC) proteins may play a role in signal-regulated calcium entry and calcium homeostasis in myometrium. The objective of this study was to determine the relative abundance of specific TrpC mRNAs expressed in human myometrium and determine if TrpC mRNA and protein concentrations differ in fundal myometrium before and after the onset of labor. METHODS A quantitative real-time polymerase chain reaction (Q-RT-PCR) procedure was developed for determining the concentration of TrpC mRNA expression in immortalized and primary human myometrial cells and myometrial fundus tissues from patients before and after the onset of labor. The corresponding TrpC proteins were detected by Western blot analysis and immunohistochemistry. RESULTS hTrpC1, 3, 4, 5, 6, and 7 mRNAs were expressed in two lines of immortalized human myometrial cells and in primary human myocytes. In all of these cells, hTrpC1 and hTrpC4 mRNAs were the most abundant, followed by hTrpC6. A similar distribution was observed in fundal myometrium samples from patients before and after the onset of labor. hTrpC4 mRNA was significantly lower after the onset of labor; there were no significant changes in the concentrations of other TrpC mRNAs. Immunohistochemistry identified hTrpC1, 3, 4, and 6 proteins in myometrial smooth muscle cells. Western blot analysis of myometrial membranes demonstrated no statistically significant changes in hTrpC1, 3, 4, and 6 proteins between samples collected before and after the onset of labor. CONCLUSIONS We have demonstrated that hTrpC1 and hTrpC4 are the most abundant TrpC mRNAs in human myometrium, with TrpC6 being the next most abundant. There was no increase in TrpC mRNA or protein in fundal myometrium with the onset of labor. Nonetheless, these isoforms may play significant roles in signal regulated calcium entry in human myometrium.
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Affiliation(s)
- Chun-Ying Ku
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
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29
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Store-Operated Calcium Entry in Müller Glia Is Controlled by Synergistic Activation of TRPC and Orai Channels. J Neurosci 2016; 36:3184-98. [PMID: 26985029 DOI: 10.1523/jneurosci.4069-15.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED The endoplasmic reticulum (ER) is at the epicenter of astrocyte Ca(2+) signaling. We sought to identify the molecular mechanism underlying store-operated calcium entry that replenishes ER stores in mouse Müller cells. Store depletion, induced through blockade of sequestration transporters in Ca(2+)-free saline, induced synergistic activation of canonical transient receptor potential 1 (TRPC1) and Orai channels. Store-operated TRPC1 channels were identified by their electrophysiological properties, pharmacological blockers, and ablation of the Trpc1 gene. Ca(2+) release-activated currents (ICRAC) were identified by ion permeability, voltage dependence, and sensitivity to selective Orai antagonists Synta66 and GSK7975A. Depletion-evoked calcium influx was initiated at the Müller end-foot and apical process, triggering centrifugal propagation of Ca(2+) waves into the cell body. EM analysis of the end-foot compartment showed high-density ER cisternae that shadow retinal ganglion cell (RGC) somata and axons, protoplasmic astrocytes, vascular endothelial cells, and ER-mitochondrial contacts at the vitreal surface of the end-foot. The mouse retina expresses transcripts encoding both Stim and all known Orai genes; Müller glia predominantly express stromal interacting molecule 1 (STIM1), whereas STIM2 is mainly confined to the outer plexiform and RGC layers. Elimination of TRPC1 facilitated Müller gliosis induced by the elevation of intraocular pressure, suggesting that TRPC channels might play a neuroprotective role during mechanical stress. By characterizing the properties of store-operated signaling pathways in Müller cells, these studies expand the current knowledge about the functional roles these cells play in retinal physiology and pathology while also providing further evidence for the complexity of calcium signaling mechanisms in CNS astroglia. SIGNIFICANCE STATEMENT Store-operated Ca(2+) signaling represents a major signaling pathway and source of cytosolic Ca(2+) in astrocytes. Here, we show that the store-operated response in Müller cells, radial glia that perform key structural, signaling, osmoregulatory, and mechanosensory functions within the retina, is mediated through synergistic activation of transient receptor potential and Orai channels. The end-foot disproportionately expresses the depletion sensor stromal interacting molecule 1, which contains an extraordinarily high density of endoplasmic reticulum cisternae that shadow neuronal, astrocytic, vascular, and axonal structures; interface with mitochondria; but also originate store-operated Ca(2+) entry-induced transcellular Ca(2+) waves that propagate glial excitation into the proximal retina. These results identify a molecular mechanism that underlies complex interactions between the plasma membrane and calcium stores, and contributes to astroglial function, regulation, and response to mechanical stress.
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Sousa-Valente J, Andreou AP, Urban L, Nagy I. Transient receptor potential ion channels in primary sensory neurons as targets for novel analgesics. Br J Pharmacol 2014; 171:2508-27. [PMID: 24283624 DOI: 10.1111/bph.12532] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/11/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022] Open
Abstract
The last decade has witnessed an explosion in novel findings relating to the molecules involved in mediating the sensation of pain in humans. Transient receptor potential (TRP) ion channels emerged as the greatest group of molecules involved in the transduction of various physical stimuli into neuronal signals in primary sensory neurons, as well as, in the development of pain. Here, we review the role of TRP ion channels in primary sensory neurons in the development of pain associated with peripheral pathologies and possible strategies to translate preclinical data into the development of effective new analgesics. Based on available evidence, we argue that nociception-related TRP channels on primary sensory neurons provide highly valuable targets for the development of novel analgesics and that, in order to reduce possible undesirable side effects, novel analgesics should prevent the translocation from the cytoplasm to the cell membrane and the sensitization of the channels rather than blocking the channel pore or binding sites for exogenous or endogenous activators.
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Affiliation(s)
- J Sousa-Valente
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK
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31
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Zhang E, Liao P. Brain transient receptor potential channels and stroke. J Neurosci Res 2014; 93:1165-83. [PMID: 25502473 DOI: 10.1002/jnr.23529] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/10/2014] [Accepted: 11/04/2014] [Indexed: 02/06/2023]
Abstract
Transient receptor potential (TRP) channels have been increasingly implicated in the pathological mechanisms of CNS disorders. TRP expression has been detected in neurons, astrocytes, oligodendrocytes, microglia, and ependymal cells as well as in the cerebral vascular endothelium and smooth muscle. In stroke, TRPC3/4/6, TRPM2/4/7, and TRPV1/3/4 channels have been found to participate in ischemia-induced cell death, whereas other TRP channels, in particular those expressed in nonneuronal cells, have been less well studied. This review summarizes the current knowledge on the expression and functions of the TRP channels in various cell types in the brain and our current understanding of TRP channels in stroke pathophysiology. In an aging society, the occurrence of stroke is expected to increase steadily, and there is an urgent requirement to improve the current stroke management strategy. Therefore, elucidating the roles of TRP channels in stroke could shed light on the development of novel therapeutic strategies and ultimately improve stroke outcome.
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Affiliation(s)
- Eric Zhang
- Calcium Signalling Laboratory, National Neuroscience Institute, Singapore
| | - Ping Liao
- Calcium Signalling Laboratory, National Neuroscience Institute, Singapore.,Duke-NUS Graduate Medical School Singapore, Singapore
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32
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Classical Transient Receptor Potential 1 (TRPC1): Channel or Channel Regulator? Cells 2014; 3:939-62. [PMID: 25268281 PMCID: PMC4276908 DOI: 10.3390/cells3040939] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/07/2014] [Accepted: 09/18/2014] [Indexed: 11/16/2022] Open
Abstract
In contrast to other Classical Transient Receptor Potential TRPC channels the function of TRPC1 as an ion channel is a matter of debate, because it is often difficult to obtain substantial functional signals over background in response to over-expression of TRPC1 alone. Along these lines, heterologously expressed TRPC1 is poorly translocated to the plasma membrane as a homotetramer and may not function on its own physiologically, but may rather be an important linker and regulator protein in heteromeric TRPC channel tetramers. However, due to the lack of specific TRPC1 antibodies able to detect native TRPC1 channels in primary cells, identification of functional TRPC1 containing heteromeric TRPC channel complexes in the plasma membrane is still challenging. Moreover, an extended TRPC1 cDNA, which was recently discovered, may seriously question results obtained in heterologous expression systems transfected with shortened cDNA versions. Therefore, this review will focus on the current status of research on TRPC1 function obtained in primary cells and a TRPC1-deficient mouse model.
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33
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Albarran L, Berna-Erro A, Dionisio N, Redondo PC, Lopez E, Lopez JJ, Salido GM, Brull Sabate JM, Rosado JA. TRPC6 participates in the regulation of cytosolic basal calcium concentration in murine resting platelets. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:789-96. [DOI: 10.1016/j.bbamcr.2014.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
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Woo JS, Lee KJ, Huang M, Cho CH, Lee EH. Heteromeric TRPC3 with TRPC1 formed via its ankyrin repeats regulates the resting cytosolic Ca2+ levels in skeletal muscle. Biochem Biophys Res Commun 2014; 446:454-9. [PMID: 24613381 DOI: 10.1016/j.bbrc.2014.02.127] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 02/26/2014] [Indexed: 01/05/2023]
Abstract
The main tasks of skeletal muscle are muscle contraction and relaxation, which are mediated by changes in cytosolic Ca(2+) levels. Canonical-type transient receptor potential 3 (TRPC3) contains an ankyrin repeat (AR) region at the N-terminus (38-188 amino acids) and forms extracellular Ca(2+)-entry channels by homo or heteromerization with other TRP subtypes in various cells including skeletal myotubes. However, previous research has not determined which region(s) of TRPC3 is responsible for the heteromerization, whether the AR region participates in the heteromerizations, or what is the role of heteromeric TRPC3s in skeletal muscle. In the present study, the heteromerization of TRPC3 with TRPC1 was first examined by GST pull-down assays of TRPC3 portions with TRPC1. The portion containing the AR region of TRPC3 was bound to the TRPC1, but the binding was inhibited by the very end sub-region of the TRPC3 (1-37 amino acids). In-silico studies have suggested that the very end sub-region possibly induces a structural change in the AR region. Second, the very end sub-region of TRPC3 was expressed in mouse primary skeletal myotubes, resulting in a dominant-negative inhibition of heteromeric TRPC3/1 formation. In addition, the skeletal myotubes expressing the very end sub-region showed a decrease in resting cytosolic Ca(2+) levels. These results suggest that the AR region of TRPC3 could mediate the heteromeric TRPC3/1 formation, and the heteromeric TRPC3/1 could participate in regulating the resting cytosolic Ca(2+) levels in skeletal muscle.
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Affiliation(s)
- Jin Seok Woo
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Keon Jin Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Mei Huang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Chung-Hyun Cho
- Department of Pharmacology and Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul 110-799, Republic of Korea
| | - Eun Hui Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
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35
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Zhang Z, Yu H, Huang J, Faouzi M, Schmitz C, Penner R, Fleig A. The TRPM6 kinase domain determines the Mg·ATP sensitivity of TRPM7/M6 heteromeric ion channels. J Biol Chem 2014; 289:5217-27. [PMID: 24385424 DOI: 10.1074/jbc.m113.512285] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The transient receptor potential melastatin member 7 (TRPM7) and member 6 (TRPM6) are divalent cation channel kinases essential for magnesium (Mg(2+)) homeostasis in vertebrates. It remains unclear how TRPM6 affects divalent cation transport and whether this involves functional homomeric TRPM6 plasma membrane channels or heteromeric channel assemblies with TRPM7. We show that homomeric TRPM6 is highly sensitive to intracellular free Mg(2+) and therefore unlikely to be active at physiological levels of [Mg(2+)]i. Co-expression of TRPM7 and TRPM6 produces heteromeric TRPM7/M6 channels with altered pharmacology and sensitivity to intracellular Mg·ATP compared with homomeric TRPM7. Strikingly, the activity of heteromeric TRPM7/M6 channels is independent of intracellular Mg·ATP concentrations, essentially uncoupling channel activity from cellular energy status. Disruption of TRPM6 kinase phosphorylation activity re-introduces Mg·ATP sensitivity to the heteromeric channel similar to that of TRPM7. Thus, TRPM6 modulates the functionality of TRPM7, and the TRPM6 kinase plays a critical role in tuning the phenotype of the TRPM7·M6 channel complex.
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Affiliation(s)
- Zheng Zhang
- From the Laboratory of Cell and Molecular Signaling, Center for Biomedical Research, The Queen's Medical Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813 and
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Abstract
The TRPC1 ion channel was the first mammalian TRP channel to be cloned. In humans, it is encoded by the TRPC1 gene located in chromosome 3. The protein is predicted to consist of six transmembrane segments with the N- and C-termini located in the cytoplasm. The extracellular loop connecting transmembrane segments 5 and 6 participates in the formation of the ionic pore region. Inside the cell, TRPC1 is present in the endoplasmic reticulum, plasma membrane, intracellular vesicles, and primary cilium, an antenna-like sensory organelle functioning as a signaling platform. In human and rodent tissues, it shows an almost ubiquitous expression. TRPC1 interacts with a diverse group of proteins including ion channel subunits, receptors, and cytosolic proteins to mediate its effect on Ca(2+) signaling. It primarily functions as a cation nonselective channel within pathways controlling Ca(2+) entry in response to cell surface receptor activation. Through these pathways, it affects basic cell functions, such as proliferation and survival, differentiation, secretion, and cell migration, as well as cell type-specific functions such as chemotropic turning of neuronal growth cones and myoblast fusion. The biological role of TRPC1 has been studied in genetically engineered mice where the Trpc1 gene has been experimentally ablated. Although these mice live to adulthood, they show defects in several organs and tissues, such as the cardiovascular, central nervous, skeletal and muscular, and immune systems. Genetic and functional studies have implicated TRPC1 in diabetic nephropathy, Parkinson's disease, Huntington's disease, Duchenne muscular dystrophy, cancer, seizures, and Darier-White skin disease.
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Affiliation(s)
- Vasyl Nesin
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma City, OK, 73104, USA
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Abstract
TRPC3 represents one of the first identified mammalian relative of the Drosophila trp gene product. Despite extensive biochemical and biophysical characterization as well as ambitious attempts to uncover its physiological role in native cell systems, the channel protein still represents a rather enigmatic member of the TRP superfamily. TRPC3 is significantly expressed in the brain and heart and appears of (patho)physiological importance in both non-excitable and excitable cells, being potentially involved in a wide spectrum of Ca(2+) signaling mechanisms. TRPC3 cation channels display unique gating and regulatory properties that allow for recognition and integration of multiple input stimuli including lipid mediators, cellular Ca(2+) gradients, as well as redox signals. Physiological/pathophysiological functions of this highly versatile cation channel protein are as yet incompletely understood. Its ability to associate in a dynamic manner with a variety of partner proteins enables TRPC3 to serve coordination of multiple downstream signaling pathways and control of divergent cellular functions. Here, we summarize current knowledge on ion channel features as well as possible signaling functions of TRPC3 and discuss the potential biological relevance of this signaling molecule.
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Affiliation(s)
- Michaela Lichtenegger
- Institute of Pharmaceutical Sciences - Pharmacology and Toxicology, University of Graz, A-8010, Graz, Austria
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38
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Nedungadi TP, Cunningham JT. Differential regulation of TRPC4 in the vasopressin magnocellular system by water deprivation and hepatic cirrhosis in the rat. Am J Physiol Regul Integr Comp Physiol 2013; 306:R304-14. [PMID: 24352411 DOI: 10.1152/ajpregu.00388.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transient receptor potential canonical subtype 4 (TRPC4) is expressed in the magnocellular paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus. In this study, the regulation of TRPC4 expression was investigated in water deprivation and hepatic cirrhosis. We used laser capture microdissection technique for precise dissection of pure AVP cell population in the PVN and SON followed by quantitative real-time RT-PCR, and immunodetection techniques by Western blot analysis and immunofluorescence. Bile duct ligation elevated TRPC4 transcripts in the SON but not PVN with correlated changes in the protein expression in these regions, as well as increased colocalization with AVP in the SON, with no changes in the PVN. Water deprivation resulted in increased TRPC4 mRNA expression in the PVN, while it decreased channel expression levels in the SON. In both of these regions, protein expression measured from tissue punches were unaltered following water deprivation, with no changes in the number of TRPC4-positive cells. Thus, TRPC4 expression is differentially regulated in physiological and pathophysiological models of vasopressin release.
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Affiliation(s)
- T Prashant Nedungadi
- Department of Integrative Physiology, and Cardiovascular Research Institute, University of North Texas Health Science Centre at Fort Worth, Fort Worth, Texas
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39
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Abstract
TRP channels constitute a large superfamily of cation channel forming proteins, all related to the gene product of the transient receptor potential (trp) locus in Drosophila. In mammals, 28 different TRP channel genes have been identified, which exhibit a large variety of functional properties and play diverse cellular and physiological roles. In this article, we provide a brief and systematic summary of expression, function, and (patho)physiological role of the mammalian TRP channels.
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Affiliation(s)
- Maarten Gees
- Laboratory Ion Channel Research and TRP Research Platform Leuven (TRPLe), KU Leuven, Campus Gasthuisberg, Leuven, Belgium
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40
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A network perspective on unraveling the role of TRP channels in biology and disease. Pflugers Arch 2013; 466:173-82. [PMID: 23677537 DOI: 10.1007/s00424-013-1292-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/22/2013] [Accepted: 05/03/2013] [Indexed: 02/08/2023]
Abstract
Transient receptor potential (TRP) channels are a large family of non-selective cation channels that mediate numerous physiological and pathophysiological processes; however, still largely unknown are the underlying molecular mechanisms. With data generated on an unprecedented scale, network-based approaches have been revolutionizing the way in which we understand biology and disease, discover disease genes, and develop therapeutic strategies. These circumstances have created opportunities to encounter TRP channel research to data-intensive science. In this review, we provide an introduction of network-based approaches in biomedical science, describe the current state of TRP channel network biology, and discuss the future direction of TRP channel research. Network perspective will facilitate the discovery of latent roles and underlying mechanisms of TRP channels in biology and disease.
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Furutani N, Hondo M, Kageyama H, Tsujino N, Mieda M, Yanagisawa M, Shioda S, Sakurai T. Neurotensin co-expressed in orexin-producing neurons in the lateral hypothalamus plays an important role in regulation of sleep/wakefulness states. PLoS One 2013; 8:e62391. [PMID: 23620827 PMCID: PMC3631195 DOI: 10.1371/journal.pone.0062391] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 03/24/2013] [Indexed: 02/03/2023] Open
Abstract
Both orexin and neurotensin are expressed in the lateral hypothalamic area (LHA) and have been implicated in the regulation of feeding, motor activity and the reward system. A double label immunofluorescence and in situ hybridization studies showed that neurotensin colocalizes with orexin in neurons of the LHA. Pharmacological studies suggested that neurotensin excites orexin-producing neurons (orexin neurons) through activation of neurotensin receptor-2 (NTSR-2) and non-selective cation channels. In situ hybridization study showed that most orexin neurons express neurotensin receptor-2 mRNA but not neurotensin receptor-1 (Ntsr-1) mRNA. Immunohistochemical studies showed that neurotensin-immunoreactive fibers make appositions to orexin neurons. A neurotensin receptor antagonist decreased Fos expression in orexin neurons and wakefulness time in wild type mice when administered intraperitoneally. However, the antagonist did not evoke any effect on these parameters in orexin neuron-ablated mice. These observations suggest the importance of neurotensin in maintaining activity of orexin neurons. The evidence presented here expands our understanding of the regulatory mechanism of orexin neurons.
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Affiliation(s)
- Naoki Furutani
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Mari Hondo
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
- Center for Behavioral Molecular Genetics, University of Tsukuba, Tsukuba, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - Haruaki Kageyama
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Natsuko Tsujino
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Michihiro Mieda
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Masashi Yanagisawa
- Center for Behavioral Molecular Genetics, University of Tsukuba, Tsukuba, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Seiji Shioda
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
- * E-mail:
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42
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Sugawara Y, Echigo R, Kashima K, Minami H, Watanabe M, Nishikawa Y, Muranishi M, Yoneda M, Ohno-Shosaku T. Intracellular calcium level is an important factor influencing ion channel modulations by PLC-coupled metabotropic receptors in hippocampal neurons. Brain Res 2013; 1512:9-21. [PMID: 23548601 DOI: 10.1016/j.brainres.2013.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
Abstract
Signaling pathways involving phospholipase C (PLC) are involved in various neural functions. Understanding how these pathways are regulated will lead to a better understanding of their roles in neural functions. Previous studies demonstrated that receptor-driven PLCβ activation depends on intracellular Ca(2+) concentration ([Ca(2+)]i), suggesting the possibility that PLCβ-dependent cellular responses are basically Ca(2+) dependent. To test this possibility, we examined whether modulations of ion channels driven by PLC-coupled metabotropic receptors are sensitive to [Ca(2+)]i using cultured hippocampal neurons. Muscarinic activation triggered an inward current at -100 mV (the equilibrium potential for K(+)) in a subpopulation of neurons. This current response was suppressed by pirenzepine (an M1-preferring antagonist), PLC inhibitor, non-selective cation channel blocker, and lowering [Ca(2+)]i. Using the neurons showing no response at -100 mV, effects of muscarinic activation on K(+) channels were examined at -40 mV. Muscarinic activation induced a transient decrease of the holding outward current. This current response was mimicked and occluded by XE991, an M-current K(+) channel blocker, suppressed by pirenzepine, PLC inhibitor and lowering [Ca(2+)]i, and enhanced by elevating [Ca(2+)]i. Similar results were obtained when group I metabotropic glutamate receptors were activated instead of muscarinic receptors. These results clearly show that ion channel modulations driven by PLC-coupled metabotropic receptors are dependent on [Ca(2+)]i, supporting the hypothesis that cellular responses induced by receptor-driven PLCβ activation are basically Ca(2+) dependent.
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Affiliation(s)
- Yuto Sugawara
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
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43
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Streifel K, Miller J, Mouneimne R, Tjalkens RB. Manganese inhibits ATP-induced calcium entry through the transient receptor potential channel TRPC3 in astrocytes. Neurotoxicology 2013; 34:160-6. [PMID: 23131343 PMCID: PMC3557543 DOI: 10.1016/j.neuro.2012.10.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/05/2012] [Accepted: 10/25/2012] [Indexed: 11/26/2022]
Abstract
Chronic exposure to elevated levels of manganese (Mn(2+)) causes neuronal injury and inflammatory activation of glia. Astrocytes selectively accumulate Mn(2+), which inhibits mitochondrial respiration and increases production of reactive oxygen species. We previously reported that sub-acute exposure to low micromolar levels of Mn(2+) in primary astrocytes inhibited ATP-induced calcium (Ca(2+)) signaling, associated with decreased levels of endoplasmic reticulum Ca(2+) and increased mitochondrial Ca(2+) loads. In the present studies, we postulated that the mechanism underlying the capacity of Mn(2+) to inhibit these purinergic signals in astrocytes could be due to competition with Ca(2+) for entry through a plasma membrane channel. These data demonstrate that acutely applied Mn(2+) rapidly inhibited ATP-induced Ca(2+) waves and transients in primary striatal astrocytes. Mn(2+) also decreased influx of extracellular Ca(2+) induced by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a direct activator of the transient receptor potential channel, TRPC3. The TRPC3 inhibitor, pyrazole-3, prevented ATP- and OAG-dependent transport of Mn(2+) from extracellular stores, demonstrated by a dramatic reduction in the rate of fluorescence quenching of Fura-2. These data indicate that Mn(2+) can acutely inhibit ATP-dependent Ca(2+) signaling in astrocytes by blocking Ca(2+) entry through the receptor-operated cation channel, TRPC3. Loss of normal astrocytic responses to purinergic signals due to accumulation of Mn(2+) could therefore comprise critical homeostatic functions necessary for metabolic and trophic support of neurons.
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Affiliation(s)
- Karin Streifel
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
| | - James Miller
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
| | - Rola Mouneimne
- Department of Veterinary Integrative Biosciences, Texas A&M University
| | - Ronald B. Tjalkens
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
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Ho TC, Horn NA, Huynh T, Kelava L, Lansman JB. Evidence TRPV4 contributes to mechanosensitive ion channels in mouse skeletal muscle fibers. Channels (Austin) 2012; 6:246-54. [PMID: 22785252 DOI: 10.4161/chan.20719] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We recorded the activity of single mechanosensitive (MS) ion channels from membrane patches on single muscle fibers isolated from mice. We investigated the actions of various TRP (transient receptor potential) channel blockers on MS channel activity. 2-aminoethoxydiphenyl borate (2-APB) neither inhibited nor facilitated single channel activity at submillimolar concentrations. The absence of an effect of 2-APB indicates MS channels are not composed purely of TRPC or TRPV1, 2 or 3 proteins. Exposing patches to 1-oleolyl-2-acetyl-sn-glycerol (OAG), a potent activator of TRPC channels, also had no effect on MS channel activity. In addition, flufenamic acid and spermidine had no effect on the activity of single MS channels. By contrast, SKF-96365 and ruthenium red blocked single-channel currents at micromolar concentrations. SKF-96365 produced a rapid block of the open channel current. The blocking rate depended linearly on blocker concentration, while the unblocking rate was independent of concentration, consistent with a simple model of open channel block. A fit to the concentration-dependence of block gave k(on) = 13 x 10 ( 6) M (-1) s (-1) and k(off) = 1609 sec (-1) with K(D) = ~124 µM. Block by ruthenium red was complex, involving both reduction of the amplitude of the single-channel current and increased occupancy of subconductance levels. The reduction in current amplitude with increasing concentration of ruthenium red gave a K(D) = ~49 µM. The high sensitivity of MS channels to block by ruthenium red suggests MS channels in skeletal muscle contain TRPV subunits. Recordings from skeletal muscle isolated from TRPV4 knockout mice failed to show MS channel activity, consistent with a contribution of TRPV4. In addition, exposure to hypo-osmotic solutions increases opening of MS channels in muscle. Our results provide evidence TRPV4 contributes to MS channels in skeletal muscle.
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Affiliation(s)
- Tiffany C Ho
- Department of Cellular and Molecular Pharmacology, School of Medicine, University of California, San Francisco, San Francisco, CA, USA
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45
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Freichel M, Almering J, Tsvilovskyy V. The Role of TRP Proteins in Mast Cells. Front Immunol 2012; 3:150. [PMID: 22701456 PMCID: PMC3372879 DOI: 10.3389/fimmu.2012.00150] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/22/2012] [Indexed: 01/16/2023] Open
Abstract
Transient receptor potential (TRP) proteins form cation channels that are regulated through strikingly diverse mechanisms including multiple cell surface receptors, changes in temperature, in pH and osmolarity, in cytosolic free Ca(2+) concentration ([Ca(2+)](i)), and by phosphoinositides which makes them polymodal sensors for fine tuning of many cellular and systemic processes in the body. The 28 TRP proteins identified in mammals are classified into six subfamilies: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. When activated, they contribute to cell depolarization and Ca(2+) entry. In mast cells, the increase of [Ca(2+)](i) is fundamental for their biological activity, and several entry pathways for Ca(2+) and other cations were described including Ca(2+) release activated Ca(2+) (CRAC) channels. Like in other non-excitable cells, TRP channels could directly contribute to Ca(2+) influx via the plasma membrane as constituents of Ca(2+) conducting channel complexes or indirectly by shifting the membrane potential and regulation of the driving force for Ca(2+) entry through independent Ca(2+) entry channels. Here, we summarize the current knowledge about the expression of individual Trp genes with the majority of the 28 members being yet identified in different mast cell models, and we highlight mechanisms how they can regulate mast cell functions. Since specific agonists or blockers are still lacking for most members of the TRP family, studies to unravel their function and activation mode still rely on experiments using genetic approaches and transgenic animals. RNAi approaches suggest a functional role for TRPC1, TRPC5, and TRPM7 in mast cell derived cell lines or primary mast cells, and studies using Trp gene knock-out mice reveal a critical role for TRPM4 in mast cell activation and for mast cell mediated cutaneous anaphylaxis, whereas a direct role of cold- and menthol-activated TRPM8 channels seems to be unlikely for the development of cold urticaria at least in mice.
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Affiliation(s)
- Marc Freichel
- Pharmakologisches Institut, Universität HeidelbergHeidelberg, Germany
| | - Julia Almering
- Pharmakologisches Institut, Universität HeidelbergHeidelberg, Germany
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Molnar T, Barabas P, Birnbaumer L, Punzo C, Kefalov V, Križaj D. Store-operated channels regulate intracellular calcium in mammalian rods. J Physiol 2012; 590:3465-81. [PMID: 22674725 DOI: 10.1113/jphysiol.2012.234641] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Exposure to daylight closes cyclic nucleotide-gated (CNG) and voltage-operated Ca(2+) -permeable channels in mammalian rods. The consequent lowering of the cytosolic calcium concentration ([Ca(2+)](i)), if protracted, can contribute to light-induced damage and apoptosis in these cells. We here report that mouse rods are protected against prolonged lowering of [Ca(2+)](i) by store-operated Ca(2+) entry (SOCE). Ca(2+) stores were depleted in Ca(2+)-free saline supplemented with the endoplasmic reticulum (ER) sequestration blocker cyclopiazonic acid. Store depletion elicited [Ca(2+)](i) signals that exceeded baseline [Ca(2+)](i) by 5.9 ± 0.7-fold and were antagonized by an inhibitory cocktail containing 2-APB, SKF 96365 and Gd(3+). Cation influx through SOCE channels was sufficient to elicit a secondary activation of L-type voltage-operated Ca2+ entry. We also found that TRPC1, the type 1 canonical mammalian homologue of the Drosophila photoreceptor TRP channel, is predominantly expressed within the outer nuclear layer of the retina. Rod loss in Pde6b(rdl) (rd1), Chx10/Kip1(-/-rdl) and Elovl4(TG2) dystrophic models was associated with ∼70% reduction in Trpc1 mRNA content whereas Trpc1 mRNA levels in rodless cone-full Nrl(-/-) retinas were decreased by ∼50%. Genetic ablation of TRPC1 channels, however, had no effect on SOCE, the sensitivity of the rod phototransduction cascade or synaptic transmission at rod and cone synapses. Thus, we localized two new mechanisms, SOCE and TRPC1, to mammalian rods and characterized the contribution of SOCE to Ca(2+) homeostasis. By preventing the cytosolic [Ca(2+)](i) from dropping too low under sustained saturating light conditions, these signalling pathways may protect Ca(2+)-dependent mechanisms within the ER and the cytosol without affecting normal rod function.
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Affiliation(s)
- Tünde Molnar
- Department of Ophthalmology & Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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Abstract
Transient receptor potential canonical (TRPC) channels are the canonical (C) subset of the TRP proteins, which are widely expressed in mammalian cells. They are thought to be primarily involved in determining calcium and sodium entry and have wide-ranging functions that include regulation of cell proliferation, motility and contraction. The channels are modulated by a multiplicity of factors, putatively existing as integrators in the plasma membrane. This review considers the sensitivities of TRPC channels to lipids that include diacylglycerols, phosphatidylinositol bisphosphate, lysophospholipids, oxidized phospholipids, arachidonic acid and its metabolites, sphingosine-1-phosphate, cholesterol and some steroidal derivatives and other lipid factors such as gangliosides. Promiscuous and selective lipid sensing have been detected. There appear to be close working relationships with lipids of the phospholipase C and A2 enzyme systems, which may enable integration with receptor signalling and membrane stretch. There are differences in the properties of each TRPC channel that are further complicated by TRPC heteromultimerization. The lipids modulate activity of the channels or insertion in the plasma membrane. Lipid microenvironments and intermediate sensing proteins have been described that include caveolae, G protein signalling, SEC14-like and spectrin-type domains 1 (SESTD1) and podocin. The data suggest that lipid sensing is an important aspect of TRPC channel biology enabling integration with other signalling systems.
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Affiliation(s)
- D. J. Beech
- Faculty of Biological Sciences, Institute of Membrane and Systems Biology, University of Leeds, Leeds, UK
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48
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Storch U, Forst AL, Philipp M, Gudermann T, Mederos y Schnitzler M. Transient receptor potential channel 1 (TRPC1) reduces calcium permeability in heteromeric channel complexes. J Biol Chem 2011; 287:3530-40. [PMID: 22157757 DOI: 10.1074/jbc.m111.283218] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Specific biological roles of the classical transient receptor potential channel 1 (TRPC1) are still largely elusive. To investigate the function of TRPC1 proteins in cell physiology, we studied heterologously expressed TRPC1 channels and found that recombinant TRPC1 subunits do not form functional homomeric channels. Instead, by electrophysiological analysis TRPC1 was shown to form functional heteromeric, receptor-operated channel complexes with TRPC3, -4, -5, -6, and -7 indicating that TRPC1 proteins can co-assemble with all members of the TRPC subfamily. In all TRPC1-containing heteromers, TRPC1 subunits significantly decreased calcium permeation. The exchange of select amino acids in the putative pore-forming region of TRPC1 further reduced calcium permeability, suggesting that TRPC1 subunits contribute to the channel pore. In immortalized immature gonadotropin-releasing hormone neurons endogenously expressing TRPC1, -2, -5, and -6, down-regulation of TRPC1 resulted in increased calcium permeability and elevated basal cytosolic calcium concentrations. We did not observe any involvement of TRPC1 in store-operated cation influx. Notably, TRPC1 suppressed the migration of gonadotropin-releasing hormone neurons without affecting cell proliferation. Conversely, in TRPC1 knockdown neurons, specific migratory properties like distance covered, locomotion speed, and directionality were increased. These findings suggest a novel regulatory mechanism relying on the expression of TRPC1 and the subsequent formation of heteromeric TRPC channel complexes with reduced calcium permeability, thereby fine-tuning neuronal migration.
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Affiliation(s)
- Ursula Storch
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians University, 80336 Munich, Germany
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49
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Moreno C, Vaca L. SOC and now also SIC: store-operated and store-inhibited channels. IUBMB Life 2011; 63:856-63. [PMID: 21901816 DOI: 10.1002/iub.547] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 07/02/2011] [Indexed: 12/19/2022]
Abstract
There is a specialized form of calcium influx that involves a close communication between endoplasmic reticulum and the channels at the plasma membrane. In one side store depletion activates channels known as store-operated channels (SOC), which are responsible of the well-studied store-operated calcium entry (SOCE). SOC comprises two different types of channels. Orai, which is exclusively activated by store depletion being the channel responsible of the calcium release-activated calcium current, and transient receptor potential canonical channel, which in contrast, is activated by store depletion only under specific conditions and carries nonselective cationic currents. On the other hand, it has been recently shown that store depletion also inhibits calcium channels. The first member identified, of what we named as store-inhibited channels (SIC), is the L-type voltage-gated calcium channel. Stores control both SOC and SIC by means of the multifunctional protein STIM1. The identification of SOC and SIC opens a new scenario for the role of store depletion in the modulation of different calcium entry pathways, which may satisfy different cellular processes.
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Affiliation(s)
- Claudia Moreno
- Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Del. Coyoacán, 04510 México DF, México
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50
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Miller M, Shi J, Zhu Y, Kustov M, Tian JB, Stevens A, Wu M, Xu J, Long S, Yang P, Zholos AV, Salovich JM, Weaver CD, Hopkins CR, Lindsley CW, McManus O, Li M, Zhu MX. Identification of ML204, a novel potent antagonist that selectively modulates native TRPC4/C5 ion channels. J Biol Chem 2011; 286:33436-46. [PMID: 21795696 DOI: 10.1074/jbc.m111.274167] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Transient receptor potential canonical (TRPC) channels are Ca(2+)-permeable nonselective cation channels implicated in diverse physiological functions, including smooth muscle contractility and synaptic transmission. However, lack of potent selective pharmacological inhibitors for TRPC channels has limited delineation of the roles of these channels in physiological systems. Here we report the identification and characterization of ML204 as a novel, potent, and selective TRPC4 channel inhibitor. A high throughput fluorescent screen of 305,000 compounds of the Molecular Libraries Small Molecule Repository was performed for inhibitors that blocked intracellular Ca(2+) rise in response to stimulation of mouse TRPC4β by μ-opioid receptors. ML204 inhibited TRPC4β-mediated intracellular Ca(2+) rise with an IC(50) value of 0.96 μm and exhibited 19-fold selectivity against muscarinic receptor-coupled TRPC6 channel activation. In whole-cell patch clamp recordings, ML204 blocked TRPC4β currents activated through either μ-opioid receptor stimulation or intracellular dialysis of guanosine 5'-3-O-(thio)triphosphate (GTPγS), suggesting a direct interaction of ML204 with TRPC4 channels rather than any interference with the signal transduction pathways. Selectivity studies showed no appreciable block by 10-20 μm ML204 of TRPV1, TRPV3, TRPA1, and TRPM8, as well as KCNQ2 and native voltage-gated sodium, potassium, and calcium channels in mouse dorsal root ganglion neurons. In isolated guinea pig ileal myocytes, ML204 blocked muscarinic cation currents activated by bath application of carbachol or intracellular infusion of GTPγS, demonstrating its effectiveness on native TRPC4 currents. Therefore, ML204 represents an excellent novel tool for investigation of TRPC4 channel function and may facilitate the development of therapeutics targeted to TRPC4.
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Affiliation(s)
- Melissa Miller
- Department of Neuroscience, High Throughput Biology Center, and Johns Hopkins Ion Channel Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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