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Du T, Zhou X, Zhang RDY, Du XF. Roles of Ca2+ activity in injury-induced migration of microglia in zebrafish in vivo. Biochem Biophys Rep 2022; 32:101340. [PMID: 36120493 PMCID: PMC9471311 DOI: 10.1016/j.bbrep.2022.101340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/21/2022] [Accepted: 08/30/2022] [Indexed: 10/28/2022] Open
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Yoon JY, Ho WK. Involvement of Ca2+ in Signaling Mechanisms Mediating Muscarinic Inhibition of M Currents in Sympathetic Neurons. Cell Mol Neurobiol 2022:10.1007/s10571-022-01303-7. [DOI: 10.1007/s10571-022-01303-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022]
Abstract
AbstractAcetylcholine can excite neurons by suppressing M-type (KCNQ) potassium channels. This effect is mediated by M1 muscarinic receptors coupled to the Gq protein. Although PIP2 depletion and PKC activation have been strongly suggested to contribute to muscarinic inhibition of M currents (IM), direct evidence is lacking. We investigated the mechanism involved in muscarinic inhibition of IM with Ca2+ measurement and electrophysiological studies in both neuronal (rat sympathetic neurons) and heterologous (HEK cells expressing KCNQ2/KCNQ3) preparations. We found that muscarinic inhibition of IM was not blocked either by PIP2 or by calphostin C, a PKC inhibitor. We then examined whether muscarinic inhibition of IM uses multiple signaling pathways by blocking both PIP2 depletion and PKC activation. This maneuver, however, did not block muscarinic inhibition of IM. Additionally, muscarinic inhibition of IM was not prevented either by sequestering of G-protein βγ subunits from Gα-transducin or anti-Gβγ antibody or by preventing intracellular trafficking of channel proteins with blebbistatin, a class-II myosin inhibitor. Finally, we re-examined the role of Ca2+ signals in muscarinic inhibition of IM. Ca2+ measurements showed that muscarinic stimulation increased intracellular Ca2+ and was comparable to the Ca2+ mobilizing effect of bradykinin. Accordingly, 20-mM of BAPTA significantly suppressed muscarinic inhibition of IM. In contrast, muscarinic inhibition of IM was completely insensitive to 20-mM EGTA. Taken together, these data suggest a role of Ca2+ signaling in muscarinic modulation of IM. The differential effects of EGTA and BAPTA imply that Ca2+ microdomains or spatially local Ca2+ signals contribute to inhibition of IM.
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Mosshammer A, Zou L, Boehm S, Schicker K. Mechanisms of sympathoexcitation via P2Y 6 receptors. Front Pharmacol 2022; 13:1014284. [PMID: 36408258 PMCID: PMC9669757 DOI: 10.3389/fphar.2022.1014284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022] Open
Abstract
Many drugs used in cardiovascular therapy, such as angiotensin receptor antagonists and beta-blockers, may exert at least some of their actions through effects on the sympathetic nervous system, and this also holds true for e.g., P2Y12 antagonists. A new target at the horizon of cardiovascular drugs is the P2Y6 receptor which contributes to the development of arteriosclerosis and hypertension. To learn whether P2Y6 receptors in the sympathetic nervous system might contribute to actions of respective receptor ligands, responses of sympathetic neurons to P2Y6 receptor activation were analyzed in primary cell culture. UDP in a concentration dependent manner caused membrane depolarization and enhanced numbers of action potentials fired in response to current injections. The excitatory action was antagonized by the P2Y6 receptor antagonist MRS2578, but not by the P2Y2 antagonist AR-C118925XX. UDP raised intracellular Ca2+ in the same range of concentrations as it enhanced excitability and elicited inward currents under conditions that favor Cl- conductances, and these were reduced by a blocker of Ca2+-activated Cl- channels, CaCCInh-A01. In addition, UDP inhibited currents through KV7 channels. The increase in numbers of action potentials caused by UDP was not altered by the KV7 channel blocker linopirdine, but was enhanced in low extracellular Cl- and was reduced by CaCCInh-A01 and by an inhibitor of phospholipase C. Moreover, UDP enhanced release of previously incorporated [3H] noradrenaline, and this was augmented in low extracellular Cl- and by linopirdine, but attenuated by CaCCInh-A01. Together, these results reveal sympathoexcitatory actions of P2Y6 receptor activation involving Ca2+-activated Cl- channels.
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Affiliation(s)
- Anna Mosshammer
- Division of Neurophysiology and Neuropharmacology, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Lifang Zou
- Division of Neurophysiology and Neuropharmacology, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Center of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, China
- Clinical Research Center for Hematologic Disease of Jiangxi Province, Nanchang, China
| | - Stefan Boehm
- Division of Neurophysiology and Neuropharmacology, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Klaus Schicker
- Division of Neurophysiology and Neuropharmacology, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Pérez-Liébana I, Juaristi I, González-Sánchez P, González-Moreno L, Rial E, Podunavac M, Zakarian A, Molgó J, Vallejo-Illarramendi A, Mosqueira-Martín L, Lopez de Munain A, Pardo B, Satrústegui J, Del Arco A. A Ca 2+-Dependent Mechanism Boosting Glycolysis and OXPHOS by Activating Aralar-Malate-Aspartate Shuttle, upon Neuronal Stimulation. J Neurosci 2022; 42:3879-3895. [PMID: 35387872 PMCID: PMC9097769 DOI: 10.1523/jneurosci.1463-21.2022] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 12/20/2021] [Accepted: 01/27/2022] [Indexed: 01/18/2023] Open
Abstract
Calcium is an important second messenger regulating a bioenergetic response to the workloads triggered by neuronal activation. In embryonic mouse cortical neurons using glucose as only fuel, activation by NMDA elicits a strong workload (ATP demand)-dependent on Na+ and Ca2+ entry, and stimulates glucose uptake, glycolysis, pyruvate and lactate production, and oxidative phosphorylation (OXPHOS) in a Ca2+-dependent way. We find that Ca2+ upregulation of glycolysis, pyruvate levels, and respiration, but not glucose uptake, all depend on Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier, component of the malate-aspartate shuttle (MAS). MAS activation increases glycolysis, pyruvate production, and respiration, a process inhibited in the presence of BAPTA-AM, suggesting that the Ca2+ binding motifs in Aralar may be involved in the activation. Mitochondrial calcium uniporter (MCU) silencing had no effect, indicating that none of these processes required MCU-dependent mitochondrial Ca2+ uptake. The neuronal respiratory response to carbachol was also dependent on Aralar, but not on MCU. We find that mouse cortical neurons are endowed with a constitutive ER-to-mitochondria Ca2+ flow maintaining basal cell bioenergetics in which ryanodine receptors, RyR2, rather than InsP3R, are responsible for Ca2+ release, and in which MCU does not participate. The results reveal that, in neurons using glucose, MCU does not participate in OXPHOS regulation under basal or stimulated conditions, while Aralar-MAS appears as the major Ca2+-dependent pathway tuning simultaneously glycolysis and OXPHOS to neuronal activation.SIGNIFICANCE STATEMENT Neuronal activation increases cell workload to restore ion gradients altered by activation. Ca2+ is involved in matching increased workload with ATP production, but the mechanisms are still unknown. We find that glycolysis, pyruvate production, and neuronal respiration are stimulated on neuronal activation in a Ca2+-dependent way, independently of effects of Ca2+ as workload inducer. Mitochondrial calcium uniporter (MCU) does not play a relevant role in Ca2+ stimulated pyruvate production and oxygen consumption as both are unchanged in MCU silenced neurons. However, Ca2+ stimulation is blunt in the absence of Aralar, a Ca2+-binding mitochondrial carrier component of Malate-Aspartate Shuttle (MAS). The results suggest that Ca2+-regulated Aralar-MAS activation upregulates glycolysis and pyruvate production, which fuels mitochondrial respiration, through regulation of cytosolic NAD+/NADH ratio.
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Affiliation(s)
- Irene Pérez-Liébana
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Inés Juaristi
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Paloma González-Sánchez
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Luis González-Moreno
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Eduardo Rial
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Madrid, 28040, Spain
| | - Maša Podunavac
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
| | - Armen Zakarian
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
| | - Jordi Molgó
- Université Paris-Saclay, CEA, Institut des Sciences du Vivant Frédéric Joliot, ERL Centre National de la Recherche Scientifique no. 9004, Département Médicaments et Technologies pour la Santé, Service d'Ingénierie Moléculaire pour la Santé, Gif sur Yvette, F-91191, France
| | - Ainara Vallejo-Illarramendi
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Laura Mosqueira-Martín
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Adolfo Lopez de Munain
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Araceli Del Arco
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla la Mancha, Toledo, 45071 Spain; and Centro Regional de Investigaciones Biomédicas, Unidad Asociada de Biomedicina, Toledo, 45071, Spain
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Montes de Oca Balderas P, Matus Núñez M, Picones A, Hernández-Cruz A. NMDAR in cultured astrocytes: Flux-independent pH sensor and flux-dependent regulator of mitochondria and plasma membrane-mitochondria bridging. FASEB J 2020; 34:16622-16644. [PMID: 33131132 DOI: 10.1096/fj.202001300r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/28/2020] [Accepted: 10/13/2020] [Indexed: 01/21/2023]
Abstract
Glutamate N-methyl-D-aspartate (NMDA) receptor (NMDAR) is critical for neurotransmission as a Ca2+ channel. Nonetheless, flux-independent signaling has also been demonstrated. Astrocytes express NMDAR distinct from its neuronal counterpart, but cultured astrocytes have no electrophysiological response to NMDA. We recently demonstrated that in cultured astrocytes, NMDA at pH6 (NMDA/pH6) acting through the NMDAR elicits flux-independent Ca2+ release from the Endoplasmic Reticulum (ER) and depletes mitochondrial membrane potential (mΔΨ). Here we show that Ca2+ release is due to pH6 sensing by NMDAR, whereas mΔΨ depletion requires both: pH6 and flux-dependent NMDAR signaling. Plasma membrane (PM) NMDAR guard a non-random distribution relative to the ER and mitochondria. Also, NMDA/pH6 induces ER stress, endocytosis, PM electrical capacitance reduction, mitochondria-ER, and -nuclear contacts. Strikingly, it also produces the formation of PM invaginations near mitochondria along with structures referred to here as PM-mitochondrial bridges (PM-m-br). These and earlier data strongly suggest PM-mitochondria communication. As proof of the concept of mass transfer, we found that NMDA/pH6 provoked mitochondria labeling by the PM dye FM-4-64FX. NMDA/pH6 caused PM depolarization, cell acidification, and Ca2+ release from most mitochondria. Finally, the MCU and microtubules were not involved in mΔΨ depletion, while actin cytoskeleton was partially involved. These findings demonstrate that NMDAR has concomitant flux-independent and flux-dependent actions in cultured astrocytes.
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Affiliation(s)
- Pavel Montes de Oca Balderas
- Unidad de Neurobiología Dinámica, Department of Neurochemistry, Instituto Nacional de Neurología y Neurocirugía, México City, México.,Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Department of Cognitive Neuroscience, Universidad Nacional Autónoma de México, México City, México
| | - Mauricio Matus Núñez
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Department of Cognitive Neuroscience, Universidad Nacional Autónoma de México, México City, México
| | - Arturo Picones
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Department of Cognitive Neuroscience, Universidad Nacional Autónoma de México, México City, México
| | - Arturo Hernández-Cruz
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Department of Cognitive Neuroscience, Universidad Nacional Autónoma de México, México City, México
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Zhang H, Zhao S, Yu J, Yang W, Liu Z, Zhang L. Medicinal chemistry perspective of TRPM2 channel inhibitors: where we are and where we might be heading? Drug Discov Today 2020; 25:2326-2334. [PMID: 33065292 DOI: 10.1016/j.drudis.2020.09.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/26/2020] [Accepted: 09/30/2020] [Indexed: 01/06/2023]
Abstract
Transient receptor potential melastatin 2 (TRPM2) is a Ca2+- permeable nonselective cation channel that is involved in diverse biological functions as a cellular sensor for oxidative stress and temperature. It has been considered a promising therapeutic target for the treatment of ischemia/reperfusion (IR) injury, inflammation, cancer, and neurodegenerative diseases. Development of highly potent and selective TRPM2 inhibitors and validation of their use in relevant disease models will advance drug discovery. In this review, we describe the molecular structures and gating mechanism of the TRPM2 channel, and offer a comprehensive review of advances in the discovery of TRPM2 inhibitors. Furthermore, we analyze the properties of reported TRPM2 inhibitors with an emphasis on how specific inhibitors targeting this channel could be better developed.
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Affiliation(s)
- Han Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Siqi Zhao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Jie Yu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Wei Yang
- Department of Biophysics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhenming Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China.
| | - Liangren Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China.
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Zhang LY, Zhang YQ, Zeng YZ, Zhu JL, Chen H, Wei XL, Liu LJ. TRPC1 inhibits the proliferation and migration of estrogen receptor-positive Breast cancer and gives a better prognosis by inhibiting the PI3K/AKT pathway. Breast Cancer Res Treat 2020; 182:21-33. [PMID: 32415497 DOI: 10.1007/s10549-020-05673-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/06/2020] [Indexed: 02/05/2023]
Abstract
PURPOSE Previous studies have indicated that transient receptor potential (TRP) channels can influence cancer development. The TRPC subfamily consists of seven subtypes, TRPC1 - TRPC7. Interestingly, the expression levels of TRPC1 have been shown to be totally different in different breast cancer cell lines. Nevertheless, the underlying mechanism remains unknown. In this study, we explore the significance of TRPC1 expression in breast cancer. METHODS Immunohistochemical TRPC1 staining was performed in 278 samples. TRPC1 expression in different breast tissues were examined. Then, the influence of TRPC1 on migration, invasion and proliferation was explored. We analyzed the protein of TRPC1 by Western blot to prove which pathway may be involved in. Finally, we use online database to predict the prognosis of TRPC1 in breast cancer. RESULTS Through immunohistochemistry and in vitro experiments, we found that the expression level of TRPC1 was higher in breast cancer cells as compared with that in normal breast epithelial cells. Moreover, the expression level of TRPC1 was different between estrogen receptor-positive (ER +) and -negative (ER -) breast cancer. It was shown that TRPC1 inhibited MCF7 cell proliferation, migration, and invasion in vitro. Western blotting revealed that TRPC1 inhibited the PI3K/AKT pathway and epithelium-mesenchymal transformation, leading to subsequent inhibition of cell proliferation and metastasis. In luminal A and luminal B patients, those with high TRPC1 expression had a better prognosis. On the contrary, in basal-like and triple-negative breast cancer (TNBC) subtypes, patients with high-TRPC1 expression had a worse prognosis. CONCLUSIONS We confirmed that TRPC1 was high expression in breast cancer. Overexpression of TRPC1 inhibits proliferation and migration of ER + breast cancer and gives a better prognosis by inhibiting PI3K/AKT pathway activation. TRPC1 may be an independent prognostic predictor in breast cancer patients.
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Affiliation(s)
- Li-Ying Zhang
- Department of Pathology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China
| | - Yong-Qu Zhang
- Department of Breast Center, Cancer Hospital of Shantou University Medical College, No.7 Raoping Road, shantou, 515031, People's Republic of China
- Department of Breast-Thyroid-Surgery, Xiang'an Hospital of Xiamen University, 2000 Xiang'an East Road, Xiamen, 361101, People's Republic of China
| | - Yun-Zhu Zeng
- Department of Pathology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China
| | - Jian-Ling Zhu
- Department of Pathology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China
| | - Huan Chen
- Department of Pathology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China
| | - Xiao-Long Wei
- Department of Pathology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China.
| | - Li-Juan Liu
- Outpatient Department of Breast Center, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515031, People's Republic of China.
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Shah S, Carver CM, Mullen P, Milne S, Lukacs V, Shapiro MS, Gamper N. Local Ca 2+ signals couple activation of TRPV1 and ANO1 sensory ion channels. Sci Signal 2020; 13:13/629/eaaw7963. [PMID: 32345727 DOI: 10.1126/scisignal.aaw7963] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ANO1 (TMEM16A) is a Ca2+-activated Cl- channel (CaCC) expressed in peripheral somatosensory neurons that are activated by painful (noxious) stimuli. These neurons also express the Ca2+-permeable channel and noxious heat sensor TRPV1, which can activate ANO1. Here, we revealed an intricate mechanism of TRPV1-ANO1 channel coupling in rat dorsal root ganglion (DRG) neurons. Simultaneous optical monitoring of CaCC activity and Ca2+ dynamics revealed that the TRPV1 ligand capsaicin activated CaCCs. However, depletion of endoplasmic reticulum (ER) Ca2+ stores reduced capsaicin-induced Ca2+ increases and CaCC activation, suggesting that ER Ca2+ release contributed to TRPV1-induced CaCC activation. ER store depletion by plasma membrane-localized TRPV1 channels was demonstrated with an ER-localized Ca2+ sensor in neurons exposed to a cell-impermeable TRPV1 ligand. Proximity ligation assays established that ANO1, TRPV1, and the IP3 receptor IP3R1 were often found in close proximity to each other. Stochastic optical reconstruction microscopy (STORM) confirmed the close association between all three channels in DRG neurons. Together, our data reveal the existence of ANO1-containing multichannel nanodomains in DRG neurons and suggest that coupling between TRPV1 and ANO1 requires ER Ca2+ release, which may be necessary to enhance ANO1 activation.
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Affiliation(s)
- Shihab Shah
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Chase M Carver
- Department of Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Pierce Mullen
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Stephen Milne
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Viktor Lukacs
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Mark S Shapiro
- Department of Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Nikita Gamper
- School of Biomedical Science, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK. .,Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, People's Republic of China
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Ong HL, Ambudkar IS. The Endoplasmic Reticulum-Plasma Membrane Junction: A Hub for Agonist Regulation of Ca 2+ Entry. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035253. [PMID: 31501196 DOI: 10.1101/cshperspect.a035253] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Stimulation of cell-surface receptors induces cytosolic Ca2+ ([Ca2+]i) increases that are detected and transduced by effector proteins for regulation of cell function. Intracellular Ca2+ release, via endoplasmic reticulum (ER) proteins inositol 1,4,5-trisphosphate receptors (IP3R) and ryanodine receptors (RyR), and Ca2+ influx, via store-operated Ca2+ entry (SOCE), contribute to the increase in [Ca2+]i The amplitude, frequency, and spatial characteristics of the [Ca2+]i increases are controlled by the compartmentalization of proteins into signaling complexes such as receptor-signaling complexes and SOCE complexes. Both complexes include protein and lipid components, located in the plasma membrane (PM) and ER. Receptor signaling initiates in the PM via phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), and culminates with the activation of IP3R in the ER. Conversely, SOCE is initiated in the ER by Ca2+-sensing stromal interaction molecule (STIM) proteins, which then interact with PM channels Orai1 and TRPC1 to activate Ca2+ entry. This review will address how ER-PM junctions serve a central role in agonist regulation of SOCE.
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Affiliation(s)
- Hwei Ling Ong
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda Maryland 20892
| | - Indu Suresh Ambudkar
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda Maryland 20892
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Rivas-Ramírez P, Reboreda A, Rueda-Ruzafa L, Herrera-Pérez S, Lamas JA. PIP 2 Mediated Inhibition of TREK Potassium Currents by Bradykinin in Mouse Sympathetic Neurons. Int J Mol Sci 2020; 21:ijms21020389. [PMID: 31936257 PMCID: PMC7014146 DOI: 10.3390/ijms21020389] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/30/2019] [Accepted: 01/02/2020] [Indexed: 12/17/2022] Open
Abstract
Bradykinin (BK), a hormone inducing pain and inflammation, is known to inhibit potassium M-currents (IM) and to increase the excitability of the superior cervical ganglion (SCG) neurons by activating the Ca2+-calmodulin pathway. M-current is also reduced by muscarinic agonists through the depletion of membrane phosphatidylinositol 4,5-biphosphate (PIP2). Similarly, the activation of muscarinic receptors inhibits the current through two-pore domain potassium channels (K2P) of the “Tandem of pore-domains in a Weakly Inward rectifying K+ channel (TWIK)-related channels” (TREK) subfamily by reducing PIP2 in mouse SCG neurons (mSCG). The aim of this work was to test and characterize the modulation of TREK channels by bradykinin. We used the perforated-patch technique to investigate riluzole (RIL) activated currents in voltage- and current-clamp experiments. RIL is a drug used in the palliative treatment of amyotrophic lateral sclerosis and, in addition to blocking voltage-dependent sodium channels, it also selectively activates the K2P channels of the TREK subfamily. A cell-attached patch-clamp was also used to investigate TREK-2 single channel currents. We report here that BK reduces spike frequency adaptation (SFA), inhibits the riluzole-activated current (IRIL), which flows mainly through TREK-2 channels, by about 45%, and reduces the open probability of identified single TREK-2 channels in cultured mSCG cells. The effect of BK on IRIL was precluded by the bradykinin receptor (B2R) antagonist HOE-140 (d-Arg-[Hyp3, Thi5, d-Tic7, Oic8]BK) but also by diC8PIP2 which prevents PIP2 depletion when phospholipase C (PLC) is activated. On the contrary, antagonizing inositol triphosphate receptors (IP3R) using 2-aminoethoxydiphenylborane (2-APB) or inhibiting protein kinase C (PKC) with bisindolylmaleimide did not affect the inhibition of IRIL by BK. In conclusion, bradykinin inhibits TREK-2 channels through the activation of B2Rs resulting in PIP2 depletion, much like we have demonstrated for muscarinic agonists. This mechanism implies that TREK channels must be relevant for the capture of information about pain and visceral inflammation.
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Abstract
Here, I recount some adventures that I and my colleagues have had over some 60 years since 1957 studying the effects of drugs and neurotransmitters on neuronal excitability and ion channel function, largely, but not exclusively, using sympathetic neurons as test objects. Studies include effects of centrally active drugs on sympathetic transmission; neuronal action and neuroglial uptake of GABA in the ganglia and brain; the action of muscarinic agonists on sympathetic neurons; the action of bradykinin on neuroblastoma-derived cells; and the identification of M-current as a target for muscarinic action, including experiments to determine its distribution, molecular composition, neurotransmitter sensitivity, and intracellular regulation by phospholipids and their hydrolysis products. Techniques used include electrophysiological recording (extracellular, intracellular microelectrode, whole-cell, and single-channel patch-clamp), autoradiography, messenger RNA and complementary DNA expression, antibody injection, antisense knockdown, and membrane-targeted lipidated peptides. I finish with some recollections about my scientific career, funding, and changes in laboratory life and pharmacology research over the past 60 years.
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Affiliation(s)
- David A. Brown
- Departments of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
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12
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N Rosalez M, Estevez-Fregoso E, Alatorre A, Abad-García A, A Soriano-Ursúa M. 2-Aminoethyldiphenyl Borinate: A Multitarget Compound with Potential as a Drug Precursor. Curr Mol Pharmacol 2020; 13:57-75. [PMID: 31654521 DOI: 10.2174/1874467212666191025145429] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Boron is considered a trace element that induces various effects in systems of the human body. However, each boron-containing compound exerts different effects. OBJECTIVE To review the effects of 2-Aminoethyldiphenyl borinate (2-APB), an organoboron compound, on the human body, but also, its effects in animal models of human disease. METHODS In this review, the information to showcase the expansion of these reported effects through interactions with several ion channels and other receptors has been reported. These effects are relevant in the biomedical and chemical fields due to the application of the reported data in developing therapeutic tools to modulate the functions of the immune, cardiovascular, gastrointestinal and nervous systems. RESULTS Accordingly, 2-APB acts as a modulator of adaptive and innate immunity, including the production of cytokines and the migration of leukocytes. Additionally, reports show that 2-APB exerts effects on neurons, smooth muscle cells and cardiomyocytes, and it provides a cytoprotective effect by the modulation and attenuation of reactive oxygen species. CONCLUSION The molecular pharmacology of 2-APB supports both its potential to act as a drug and the desirable inclusion of its moieties in new drug development. Research evaluating its efficacy in treating pain and specific maladies, such as immune, cardiovascular, gastrointestinal and neurodegenerative disorders, is scarce but interesting.
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Affiliation(s)
- Melvin N Rosalez
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis and Diaz Miron S/N, Mexico City, 11340, Mexico
| | - Elizabeth Estevez-Fregoso
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis and Diaz Miron S/N, Mexico City, 11340, Mexico
| | - Alberto Alatorre
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis and Diaz Miron S/N, Mexico City, 11340, Mexico
| | - Antonio Abad-García
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis and Diaz Miron S/N, Mexico City, 11340, Mexico
| | - Marvin A Soriano-Ursúa
- Department of Physiology, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis and Diaz Miron S/N, Mexico City, 11340, Mexico
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13
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Hagger-Vaughan N, Storm JF. Synergy of Glutamatergic and Cholinergic Modulation Induces Plateau Potentials in Hippocampal OLM Interneurons. Front Cell Neurosci 2019; 13:508. [PMID: 31780902 PMCID: PMC6861217 DOI: 10.3389/fncel.2019.00508] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/28/2019] [Indexed: 01/18/2023] Open
Abstract
Oriens-lacunosum moleculare (OLM) cells are hippocampal inhibitory interneurons that are implicated in the regulation of information flow in the CA1 circuit, inhibiting cortical inputs to distal pyramidal cell dendrites, whilst disinhibiting CA3 inputs to pyramidal cells. OLM cells express metabotropic cholinergic (mAChR) and glutamatergic (mGluR) receptors, so modulation of these cells via these receptors may contribute to switching between functional modes of the hippocampus. Using a transgenic mouse line to identify OLM cells, we found that both mAChR and mGluR activation caused the cells to exhibit long-lasting depolarizing plateau potentials following evoked spike trains. Both mAChR- and mGluR-induced plateau potentials were eliminated by blocking transient receptor potential (TRP) channels, and were dependent on intracellular calcium concentration and calcium entry. Pharmacological tests indicated that Group I mGluRs are responsible for the glutamatergic induction of plateaus. There was also a pronounced synergy between the cholinergic and glutamatergic modulation, plateau potentials being generated by agonists applied together at concentrations too low to elicit any change when applied individually. This synergy could enable OLM cells to function as coincidence detectors of different neuromodulatory systems, leading to their enhanced and prolonged activation and a functional change in information flow within the hippocampus.
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Affiliation(s)
| | - Johan F. Storm
- Brain Signaling Laboratory, Section for Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Konar A, Gupta R, Shukla RK, Maloney B, Khanna VK, Wadhwa R, Lahiri DK, Thakur MK. M1 muscarinic receptor is a key target of neuroprotection, neuroregeneration and memory recovery by i-Extract from Withania somnifera. Sci Rep 2019; 9:13990. [PMID: 31570736 PMCID: PMC6769020 DOI: 10.1038/s41598-019-48238-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 05/10/2019] [Indexed: 12/16/2022] Open
Abstract
Memory loss is one of the most tragic symptoms of Alzheimer's disease. Our laboratory has recently demonstrated that 'i-Extract' of Ashwagandha (Withania somnifera) restores memory loss in scopolamine (SC)-induced mice. The prime target of i-Extract is obscure. We hypothesize that i-Extract may primarily target muscarinic subtype acetylcholine receptors that regulate memory processes. The present study elucidates key target(s) of i-Extract via cellular, biochemical, and molecular techniques in a relevant amnesia mouse model and primary hippocampal neuronal cultures. Wild type Swiss albino mice were fed i-Extract, and hippocampal cells from naïve mice were treated with i-Extract, followed by muscarinic antagonist (dicyclomine) and agonist (pilocarpine) treatments. We measured dendritic formation and growth by immunocytochemistry, kallikrein 8 (KLK8) mRNA by reverse transcription polymerase chain reaction (RT-PCR), and levels of KLK8 and microtubule-associated protein 2, c isoform (MAP2c) proteins by western blotting. We performed muscarinic receptor radioligand binding. i-Extract stimulated an increase in dendrite growth markers, KLK8 and MAP2. Scopolamine-mediated reduction was significantly reversed by i-Extract in mouse cerebral cortex and hippocampus. Our study identified muscarinic receptor as a key target of i-Extract, providing mechanistic evidence for its clinical application in neurodegenerative cognitive disorders.
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Affiliation(s)
- Arpita Konar
- Biochemistry and Molecular Biology Laboratory, Brain Research Centre, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India
- CSIR-Institute of Genomics & Integrative Biology, New Delhi, 110025, India
| | - Richa Gupta
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, 226001, Uttar Pradesh, India
- Devision of ECD, Indian Council of Medical Research, New Delhi, 110029, India
| | - Rajendra K Shukla
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, 226001, Uttar Pradesh, India
- Department of Biochemistry, Autonomous State Medical College, Bahraich, Utter Pradesh, 271801, India
| | - Bryan Maloney
- Departments of Psychiatry, Stark Neuroscience Research Institute, Indiana University School of Medicine, 320 West 15th Street, Indianapolis, IN-46202, USA
| | - Vinay K Khanna
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, 226001, Uttar Pradesh, India
| | - Renu Wadhwa
- DBT-AIST International Laboratory for Advanced Biomedicine (DAILAB), Biomedical Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki, 305 8562, Japan.
| | - Debomoy K Lahiri
- Departments of Psychiatry, Stark Neuroscience Research Institute, Indiana University School of Medicine, 320 West 15th Street, Indianapolis, IN-46202, USA.
- Departments of Medical and Molecular Genetics, Indiana Alzheimer Disesae Center, Indiana University School of Medicine, Indianapolis, IN-46202, USA.
| | - Mahendra K Thakur
- Biochemistry and Molecular Biology Laboratory, Brain Research Centre, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India.
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15
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Makarenko VV, Peng YJ, Khan SA, Nanduri J, Fox AP, Prabhakar NR. Long-term facilitation of catecholamine secretion from adrenal chromaffin cells of neonatal rats by chronic intermittent hypoxia. J Neurophysiol 2019; 122:1874-1883. [PMID: 31483699 DOI: 10.1152/jn.00435.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In neonates, catecholamine (CA) secretion from adrenal medullary chromaffin cells (AMC) is an important mechanism for maintaining homeostasis during hypoxia. Nearly 90% of premature infants experience chronic intermittent hypoxia (IH) because of high incidence of apnea of prematurity, which is characterized by periodic stoppage of breathing. The present study examined the effects of repetitive hypoxia, designed to mimic apnea of prematurity, on CA release from AMC of neonatal rats. Neonatal rats were exposed to either control conditions or chronic intermittent hypoxia (IH) from ages postnatal days 0-5 (P0-P5), and CA release from adrenal medullary slices was measured after challenge with repetitive hypoxia (5 episodes of 30-s hypoxia, Po2 ~35 mmHg). In response to repetitive hypoxia, chronic IH-treated AMC exhibited sustained CA release, and this phenotype was not seen in control AMC. The sustained CA release was associated with long-lasting elevation of intracellular Ca2+ concentration ([Ca2+]i), which was due to store-operated Ca2+ entry (SOCE). 2-Aminoethoxydiphenyl borate, an inhibitor of SOCE, prevented the long-lasting [Ca2+]i elevation and CA release. Repetitive hypoxia increased H2O2 abundance, and polyethylene glycol (PEG)-catalase, a scavenger of H2O2 blocked this effect. PEG-catalase also prevented repetitive hypoxia-induced SOCE activation, sustained [Ca2+]i elevation, and CA release. These results demonstrate that repetitive hypoxia induces long-term facilitation of CA release in chronic IH-treated neonatal rat AMC through sustained Ca2+ influx mediated by SOCE.NEW & NOTEWORTHY Apnea of prematurity and the resulting chronic intermittent hypoxia are major clinical problems in neonates born preterm. Catecholamine release from adrenal medullary chromaffin cells maintains homeostasis during hypoxia in neonates. Our results demonstrate that chronic intermittent hypoxia induces a hitherto uncharacterized long-term facilitation of catecholamine secretion from neonatal rat chromaffin cells in response to repetitive hypoxia, simulating hypoxic episodes encountered during apnea of prematurity. The sustained catecholamine secretion might contribute to cardiovascular morbidities in infants with apnea of prematurity.
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Affiliation(s)
- Vladislav V Makarenko
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
| | - Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
| | - Shakil A Khan
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
| | - Jayasri Nanduri
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
| | - Aaron P Fox
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
| | - Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, University of Chicago, Chicago, Illinois
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16
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Kim J, Ko J, Myeong J, Kwak M, Hong C, So I. TRPC1 as a negative regulator for TRPC4 and TRPC5 channels. Pflugers Arch 2019; 471:1045-1053. [PMID: 31222490 DOI: 10.1007/s00424-019-02289-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/17/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022]
Abstract
Transient receptor potential canonical (TRPC) channels are calcium permeable, non-selective cation channels with wide tissue-specific distribution. Among 7 TRPC channels, TRPC 1/4/5 and TRPC3/6/7 are subdivided based on amino acid sequence homology. TRPC4 and TRPC5 channels exhibit cationic current with homotetrameric form, but they also form heterotetrameric channel such as TRPC1/4 or TRPC1/5 once TRPC1 is incorporated. The expression of TRPC1 is ubiquitous whereas the expressions of TRPC4 and TRPC5 are rather focused in nervous system. With the help of conditional knock-out of TPRC1, 4 and/or 5 genes, TRPC channels made of these constituents are reported to be involved in various pathophysiological functions such as seizure, anxiety-like behaviour, fear, Huntington's disease, Parkinson's disease and many others. In heterologous expression system, many issues such as activation mechanism, stoichiometry and relative cation permeabilites of homomeric or heteromeric channels have been addressed. In this review, we discussed the role of TRPC1 channel per se in plasma membrane, role of TRPC1 in heterotetrameric conformation (TRPC1/4 or TRPC1/5) and relationship between TRPC1/4/5 channels, calcium influx and voltage-gated calcium channels.
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Affiliation(s)
- Jinsung Kim
- Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea
| | - Juyeon Ko
- Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea
| | - Jongyun Myeong
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Misun Kwak
- Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea
| | - Chansik Hong
- Department of Physiology, College of Medicine, Chosun University, Kwangju, South Korea
| | - Insuk So
- Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea.
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17
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Liu YS, Hsu JW, Lin HY, Lai SW, Huang BR, Tsai CF, Lu DY. Bradykinin B1 receptor contributes to interleukin-8 production and glioblastoma migration through interaction of STAT3 and SP-1. Neuropharmacology 2019; 144:143-154. [PMID: 30366000 DOI: 10.1016/j.neuropharm.2018.10.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/20/2018] [Accepted: 10/22/2018] [Indexed: 01/05/2023]
Abstract
Glioblastoma (GBM), the most aggressive brain tumor, has a poor prognosis due to the ease of migration to surrounding healthy brain tissue. Recent studies have shown that bradykinin receptors are involved in the progression of various cancers. However, the molecular mechanism and pathological role of bradykinin receptors remains unclear. We observed the expressions of two major bradykinin receptors, B1R and B2R, in two different human GBM cell lines, U87 and GBM8901. Cytokine array analysis showed that bradykinin increases the production of interleukin (IL)-8 in GBM via B1R. Higher B1R levels correlate with IL-8 expression in U87 and GBM8901. We observed increased levels of phosphorylated STAT3 and SP-1 in the nucleus as well. Using chromatin immunoprecipitation assay, we found that STAT3 and SP-1 mediate IL-8 expression, which gets abrogated by the inhibition of FAK and STAT3. We further demonstrated that IL-8 expression and cell migration are also regulated by the SP-1. In addition, expression levels of STAT3 and SP-1 positively correlate with clinicopathological grades of gliomas. Interestingly, our results found that inhibition of HDAC increases IL-8 expression. Moreover, stimulation with bradykinin caused increases in acetylated SP-1 and p300 complex formation, which are abrogated by inhibition of FAK and STAT3. Meanwhile, knockdown of SP-1 and p300 decreased the augmentation of bradykinin-induced IL-8 expression. These results indicate that bradykinin-induced IL-8 expression is dependent on B1R which causes phosphorylated STAT3 and acetylated SP-1 to translocate to the nucleus, hence resulting in GBM migration.
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Affiliation(s)
- Yu-Shu Liu
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan
| | - Jhih-Wen Hsu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Hsiao-Yun Lin
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Sheng-Wei Lai
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
| | - Bor-Ren Huang
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan; Department of Neurosurgery, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Cheng-Fang Tsai
- Department of Biotechnology, Asia University, Taichung, Taiwan
| | - Dah-Yuu Lu
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan; Department of Photonics and Communication Engineering, Asia University, Taichung, Taiwan.
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18
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Zhang JY, Bai QK, Zhang YD. Pretreatment with simvastatin upregulates expression of BK-2R and CD11b in the ischemic penumbra of rats. J Biomed Res 2018; 32:354-360. [PMID: 29784898 PMCID: PMC6163114 DOI: 10.7555/jbr.32.20160152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductases, collectively known as statins, have been shown to minimize cerebral ischemic events in patients. We assessed the mechanisms of simvastatin pretreatment in preventing cerebral ischemia/reperfusion injury in rats using a model of middle cerebral artery occlusion (MCAO). Rats were pretreated with simvastatin 14 days prior to MCAO induction. At 3, 24, and 48 hours after reperfusion, bradykinin levels in the ischemic penumbra were assayed by ELISA, mRNA levels of bradykinin B2 receptors (BK-2Rs) and CD11b were measured by fluorescent quantitative real-time PCR (RT-PCR), and co-expression of microglia and BK-2Rs was determined by immunofluorescence. Simvastatin had no effect on bradykinin expression in the ischemic penumbra at any time point. However, the levels of BK-2R and CD11b mRNA in the ischemic penumbra, which were significantly decreased 3 hours after ischemia-reperfusion, were increased in simvastatin-pretreated rats. Moreover, the co-expression of BK-2Rs and microglia was confirmed by immunofluorescence analysis. These results suggest that the beneficial effects of simvastatin pretreatment before cerebral ischemia/reperfusion injury in rats may be partially due to increased expression of BK-2R and CD11b in the ischemic penumbra.
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Affiliation(s)
- Jian-Ying Zhang
- Department of Neurology, Pudong People's Hospital, Shanghai 201299, China
| | - Qing-Ke Bai
- Department of Neurology, Pudong People's Hospital, Shanghai 201299, China
| | - Ying-Dong Zhang
- Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, China
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19
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Hackelberg S, Oliver D. Metabotropic Acetylcholine and Glutamate Receptors Mediate PI(4,5)P 2 Depletion and Oscillations in Hippocampal CA1 Pyramidal Neurons in situ. Sci Rep 2018; 8:12987. [PMID: 30154490 PMCID: PMC6113233 DOI: 10.1038/s41598-018-31322-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/17/2018] [Indexed: 01/24/2023] Open
Abstract
The sensitivity of many ion channels to phosphatidylinositol-4,5-bisphosphate (PIP2) levels in the cell membrane suggests that PIP2 fluctuations are important and general signals modulating neuronal excitability. Yet the PIP2 dynamics of central neurons in their native environment remained largely unexplored. Here, we examined the behavior of PIP2 concentrations in response to activation of Gq-coupled neurotransmitter receptors in rat CA1 hippocampal neurons in situ in acute brain slices. Confocal microscopy of the PIP2-selective molecular sensors tubbyCT-GFP and PLCδ1-PH-GFP showed that pharmacological activation of muscarinic acetylcholine (mAChR) or group I metabotropic glutamate (mGluRI) receptors induces transient depletion of PIP2 in the soma as well as in the dendritic tree. The observed PIP2 dynamics were receptor-specific, with mAChR activation inducing stronger PIP2 depletion than mGluRI, whereas agonists of other Gαq-coupled receptors expressed in CA1 neurons did not induce measureable PIP2 depletion. Furthermore, the data show for the first time neuronal receptor-induced oscillations of membrane PIP2 concentrations. Oscillatory behavior indicated that neurons can rapidly restore PIP2 levels during persistent activation of Gq and PLC. Electrophysiological responses to receptor activation resembled PIP2 dynamics in terms of time course and receptor specificity. Our findings support a physiological function of PIP2 in regulating electrical activity.
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Affiliation(s)
- Sandra Hackelberg
- Institute of Physiology and Pathophysiology, Philipps University, 35037, Marburg, Germany
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Dominik Oliver
- Institute of Physiology and Pathophysiology, Philipps University, 35037, Marburg, Germany.
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps University, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), Marburg and Giessen, Germany.
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20
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Cyclic AMP Recruits a Discrete Intracellular Ca 2+ Store by Unmasking Hypersensitive IP 3 Receptors. Cell Rep 2017; 18:711-722. [PMID: 28099849 PMCID: PMC5276804 DOI: 10.1016/j.celrep.2016.12.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/17/2016] [Accepted: 12/19/2016] [Indexed: 12/12/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) stimulates Ca2+ release from the endoplasmic reticulum (ER), and the response is potentiated by 3′,5′-cyclic AMP (cAMP). We investigated this interaction in HEK293 cells using carbachol and parathyroid hormone (PTH) to stimulate formation of IP3 and cAMP, respectively. PTH alone had no effect on the cytosolic Ca2+ concentration, but it potentiated the Ca2+ signals evoked by carbachol. Surprisingly, however, the intracellular Ca2+ stores that respond to carbachol alone could be both emptied and refilled without affecting the subsequent response to PTH. We provide evidence that PTH unmasks high-affinity IP3 receptors within a discrete Ca2+ store. We conclude that Ca2+ stores within the ER that dynamically exchange Ca2+ with the cytosol maintain a functional independence that allows one store to be released by carbachol and another to be released by carbachol with PTH. Compartmentalization of ER Ca2+ stores adds versatility to IP3-evoked Ca2+ signals. Cyclic AMP directly potentiates IP3-evoked Ca2+ release The Ca2+ stores released by IP3 alone or IP3 with cAMP are functionally independent Cyclic AMP unmasks high-affinity IP3 receptors in a discrete ER Ca2+ store Independent regulation of discrete Ca2+ stores increases signaling versatility
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21
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Brown DA. Regulation of neural ion channels by muscarinic receptors. Neuropharmacology 2017; 136:383-400. [PMID: 29154951 DOI: 10.1016/j.neuropharm.2017.11.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 10/26/2017] [Accepted: 11/13/2017] [Indexed: 12/20/2022]
Abstract
The excitable behaviour of neurons is determined by the activity of their endogenous membrane ion channels. Since muscarinic receptors are not themselves ion channels, the acute effects of muscarinic receptor stimulation on neuronal function are governed by the effects of the receptors on these endogenous neuronal ion channels. This review considers some principles and factors determining the interaction between subtypes and classes of muscarinic receptors with neuronal ion channels, and summarizes the effects of muscarinic receptor stimulation on a number of different channels, the mechanisms of receptor - channel transduction and their direct consequences for neuronal activity. Ion channels considered include potassium channels (voltage-gated, inward rectifier and calcium activated), voltage-gated calcium channels, cation channels and chloride channels. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- David A Brown
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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22
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Keebler MV, Taylor CW. Endogenous signalling pathways and caged IP 3 evoke Ca 2+ puffs at the same abundant immobile intracellular sites. J Cell Sci 2017; 130:3728-3739. [PMID: 28893841 PMCID: PMC5702060 DOI: 10.1242/jcs.208520] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/04/2017] [Indexed: 12/18/2022] Open
Abstract
The building blocks of intracellular Ca2+ signals evoked by inositol 1,4,5-trisphosphate receptors (IP3Rs) are Ca2+ puffs, transient focal increases in Ca2+ concentration that reflect the opening of small clusters of IP3Rs. We use total internal reflection fluorescence microscopy and automated analyses to detect Ca2+ puffs evoked by photolysis of caged IP3 or activation of endogenous muscarinic receptors with carbachol in human embryonic kidney 293 cells. Ca2+ puffs evoked by carbachol initiated at an estimated 65±7 sites/cell, and the sites remained immobile for many minutes. Photolysis of caged IP3 evoked Ca2+ puffs at a similar number of sites (100±35). Increasing the carbachol concentration increased the frequency of Ca2+ puffs without unmasking additional Ca2+ release sites. By measuring responses to sequential stimulation with carbachol or photolysed caged IP3, we established that the two stimuli evoked Ca2+ puffs at the same sites. We conclude that IP3-evoked Ca2+ puffs initiate at numerous immobile sites and the sites become more likely to fire as the IP3 concentration increases; there is no evidence that endogenous signalling pathways selectively deliver IP3 to specific sites. Summary: Ca2+ puffs are the building blocks for IP3-evoked Ca2+ signals. Ca2+ puffs evoked by caged IP3 or via endogenous signalling pathways initiate at the same fixed intracellular sites.
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Affiliation(s)
- Michael V Keebler
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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23
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Lock JT, Smith IF, Parker I. Comparison of Ca 2+ puffs evoked by extracellular agonists and photoreleased IP 3. Cell Calcium 2017; 63:43-47. [PMID: 28108028 PMCID: PMC5459673 DOI: 10.1016/j.ceca.2016.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 11/19/2022]
Abstract
The inositol trisphosphate (IP3) signaling pathway evokes local Ca2+ signals (Ca2+ puffs) that arise from the concerted openings of clustered IP3 receptor/channels in the ER membrane. Physiological activation is triggered by binding of agonists to G-protein-coupled receptors (GPCRs) on the cell surface, leading to cleavage of phosphatidyl inositol bisphosphate and release of IP3 into the cytosol. Photorelease of IP3 from a caged precursor provides a convenient and widely employed means to study the final stage of IP3-mediated Ca2+ liberation, bypassing upstream signaling events to enable more precise control of the timing and relative concentration of cytosolic IP3. Here, we address whether Ca2+ puffs evoked by photoreleased IP3 fully replicate those arising from physiological agonist stimulation. We imaged puffs in individual SH-SY5Y neuroblastoma cells that were sequentially stimulated by picospritzing extracellular agonist (carbachol, CCH or bradykinin, BK) followed by photorelease of a poorly-metabolized IP3 analog, i-IP3. The centroid localizations of fluorescence signals during puffs evoked in the same cells by agonists and photorelease substantially overlapped (within ∼1μm), suggesting that IP3 from both sources accesses the same, or closely co-localized clusters of IP3Rs. Moreover, the time course and spatial spread of puffs evoked by agonists and photorelease matched closely. Because photolysis generates IP3 uniformly throughout the cytoplasm, our results imply that IP3 generated in SH-SY5Y cells by activation of receptors to CCH and BK also exerts broadly distributed actions, rather than specifically activating a subpopulation of IP3Rs that are scaffolded in close proximity to cell surface receptors to form a signaling nanodomain.
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Affiliation(s)
- Jeffrey T Lock
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, United States.
| | - Ian F Smith
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, United States.
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, United States; Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, United States.
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GRK2 Constitutively Governs Peripheral Delta Opioid Receptor Activity. Cell Rep 2016; 16:2686-2698. [PMID: 27568556 DOI: 10.1016/j.celrep.2016.07.084] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/24/2016] [Accepted: 07/27/2016] [Indexed: 01/07/2023] Open
Abstract
Opioids remain the standard for analgesic care; however, adverse effects of systemic treatments contraindicate long-term administration. While most clinical opioids target mu opioid receptors (MOR), those that target the delta class (DOR) also demonstrate analgesic efficacy. Furthermore, peripherally restrictive opioids represent an attractive direction for analgesia. However, opioid receptors including DOR are analgesically incompetent in the absence of inflammation. Here, we report that G protein-coupled receptor kinase 2 (GRK2) naively associates with plasma membrane DOR in peripheral sensory neurons to inhibit analgesic agonist efficacy. This interaction prevents optimal Gβ subunit association with the receptor, thereby reducing DOR activity. Importantly, bradykinin stimulates GRK2 movement away from DOR and onto Raf kinase inhibitory protein (RKIP). protein kinase C (PKC)-dependent RKIP phosphorylation induces GRK2 sequestration, restoring DOR functionality in sensory neurons. Together, these results expand the known function of GRK2, identifying a non-internalizing role to maintain peripheral DOR in an analgesically incompetent state.
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Abstract
UNLABELLED In neurons, loss of plasma membrane phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] leads to a decrease in exocytosis and changes in electrical excitability. Restoration of PI(4,5)P2 levels after phospholipase C activation is therefore essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We measured dynamic changes of PI(4,5)P2, phosphatidylinositol 4-phosphate, diacylglycerol, inositol 1,4,5-trisphosphate, and Ca(2+) upon muscarinic stimulation in sympathetic neurons from adult male Sprague-Dawley rats with electrophysiological and optical approaches. We used this kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show and explain faster synthesis of PI(4,5)P2 in sympathetic neurons than in electrically nonexcitable tsA201 cells. They can be used to understand dynamic effects of receptor-mediated phospholipase C activation on excitability and other PI(4,5)P2-dependent processes in neurons. SIGNIFICANCE STATEMENT Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a minor phospholipid in the cytoplasmic leaflet of the plasma membrane. Depletion of PI(4,5)P2 via phospholipase C-mediated hydrolysis leads to a decrease in exocytosis and alters electrical excitability in neurons. Restoration of PI(4,5)P2 is essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We studied the dynamics of phosphoinositide metabolism in sympathetic neurons upon muscarinic stimulation and used the kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show a several-fold faster synthesis of PI(4,5)P2 in sympathetic neurons than in an electrically nonexcitable cell line, and provide a framework for future studies of PI(4,5)P2-dependent processes in neurons.
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Extracellular Calcium Has Multiple Targets to Control Cell Proliferation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:133-56. [DOI: 10.1007/978-3-319-26974-0_7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Galandrin S, Onfroy L, Poirot MC, Sénard JM, Galés C. Delineating biased ligand efficacy at 7TM receptors from an experimental perspective. Int J Biochem Cell Biol 2016; 77:251-63. [PMID: 27107932 DOI: 10.1016/j.biocel.2016.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/15/2016] [Accepted: 04/16/2016] [Indexed: 12/17/2022]
Abstract
During the last 10 years, the concept of "biased agonism" also called "functional selectivity" swamped the pharmacology of 7 transmembrane receptors and paved the way for developing signaling pathway-selective drugs with increased efficacy and less adverse effects. Initially thought to select the activation of only a subset of the signaling pathways by the reference agonist, bias ligands revealed higher complexity as they have been shown to stabilize variable receptor conformations that associate with distinct signaling events from the reference. Today, one major challenge relies on the in vitro determination of the bias and classification of these ligands, as a prerequisite for future in vivo and clinical translation. In this review, current experimental considerations for the bias evaluation related to choice of the cellular model, of the signaling pathway as well as of the assays are presented and discussed.
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Affiliation(s)
- Ségolène Galandrin
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Lauriane Onfroy
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Mathias Charles Poirot
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France
| | - Jean-Michel Sénard
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France; Service de Pharmacologie Clinique, Faculté de médecine, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, F-31000 Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM, UMR 1048, Université Toulouse, F-31432 Toulouse, France.
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Prole DL, Taylor CW. Inositol 1,4,5-trisphosphate receptors and their protein partners as signalling hubs. J Physiol 2016; 594:2849-66. [PMID: 26830355 PMCID: PMC4887697 DOI: 10.1113/jp271139] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/06/2015] [Indexed: 01/26/2023] Open
Abstract
Inositol 1,4,5‐trisphosphate receptors (IP3Rs) are expressed in nearly all animal cells, where they mediate the release of Ca2+ from intracellular stores. The complex spatial and temporal organization of the ensuing intracellular Ca2+ signals allows selective regulation of diverse physiological responses. Interactions of IP3Rs with other proteins contribute to the specificity and speed of Ca2+ signalling pathways, and to their capacity to integrate information from other signalling pathways. In this review, we provide a comprehensive survey of the proteins proposed to interact with IP3Rs and the functional effects that these interactions produce. Interacting proteins can determine the activity of IP3Rs, facilitate their regulation by multiple signalling pathways and direct the Ca2+ that they release to specific targets. We suggest that IP3Rs function as signalling hubs through which diverse inputs are processed and then emerge as cytosolic Ca2+ signals.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
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KCNQ potassium channels in sensory system and neural circuits. Acta Pharmacol Sin 2016; 37:25-33. [PMID: 26687932 DOI: 10.1038/aps.2015.131] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/10/2015] [Indexed: 12/15/2022] Open
Abstract
M channels, an important regulator of neural excitability, are composed of four subunits of the Kv7 (KCNQ) K(+) channel family. M channels were named as such because their activity was suppressed by stimulation of muscarinic acetylcholine receptors. These channels are of particular interest because they are activated at the subthreshold membrane potentials. Furthermore, neural KCNQ channels are drug targets for the treatments of epilepsy and a variety of neurological disorders, including chronic and neuropathic pain, deafness, and mental illness. This review will update readers on the roles of KCNQ channels in the sensory system and neural circuits as well as discuss their respective mechanisms and the implications for physiology and medicine. We will also consider future perspectives and the development of additional pharmacological models, such as seizure, stroke, pain and mental illness, which work in combination with drug-design targeting of KCNQ channels. These models will hopefully deepen our understanding of KCNQ channels and provide general therapeutic prospects of related channelopathies.
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Revah O, Libman L, Fleidervish IA, Gutnick MJ. The Outwardly Rectifying Current of Layer 5 Neocortical Neurons that was Originally Identified as "Non-Specific Cationic" Is Essentially a Potassium Current. PLoS One 2015. [PMID: 26197082 PMCID: PMC4510442 DOI: 10.1371/journal.pone.0132108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
In whole-cell patch clamp recordings from layer 5 neocortical neurons, blockade of voltage gated sodium and calcium channels leaves a cesium current that is outward rectifying. This current was originally identified as a “non-specific cationic current”, and subsequently it was hypothesized that it is mediated by TRP channels. In order to test this hypothesis, we used fluorescence imaging of intracellular sodium and calcium indicators, and found no evidence to suggest that it is associated with influx of either of these ions to the cell body or dendrites. Moreover, the current is still prominent in neurons from TRPC1-/- and TRPC5-/- mice. The effects on the current of various blocking agents, and especially its sensitivity to intracellular tetraethylammonium, suggest that it is not a non-specific cationic current, but rather that it is generated by cesium-permeable delayed rectifier potassium channels.
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Affiliation(s)
- Omer Revah
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Lior Libman
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ilya A Fleidervish
- Department of Physiology and Cell Biology, Faculty of Health Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michael J Gutnick
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Costimulation of AMPA and metabotropic glutamate receptors underlies phospholipase C activation by glutamate in hippocampus. J Neurosci 2015; 35:6401-12. [PMID: 25904792 DOI: 10.1523/jneurosci.4208-14.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Glutamate, a major neurotransmitter in the brain, activates ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs, respectively). The two types of glutamate receptors interact with each other, as exemplified by the modulation of iGluRs by mGluRs. However, the other way of interaction (i.e., modulation of mGluRs by iGluRs) has not received much attention. In this study, we found that group I mGluR-specific agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) alone is not sufficient to activate phospholipase C (PLC) in rat hippocampus, while glutamate robustly activates PLC. These results suggested that additional mechanisms provided by iGluRs are involved in group I mGluR-mediated PLC activation. A series of experiments demonstrated that glutamate-induced PLC activation is mediated by mGluR5 and is facilitated by local Ca(2+) signals that are induced by AMPA-mediated depolarization and L-type Ca(2+) channel activation. Finally, we found that PLC and L-type Ca(2+) channels are involved in hippocampal mGluR-dependent long-term depression (mGluR-LTD) induced by paired-pulse low-frequency stimulation, but not in DHPG-induced chemical LTD. Together, we propose that AMPA receptors initiate Ca(2+) influx via the L-type Ca(2+) channels that facilitate mGluR5-PLC signaling cascades, which underlie mGluR-LTD in rat hippocampus.
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Phosphoinositide dynamics in the postsynaptic membrane compartment: Mechanisms and experimental approach. Eur J Cell Biol 2015; 94:401-14. [DOI: 10.1016/j.ejcb.2015.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Bouhadfane M, Kaszás A, Rózsa B, Harris-Warrick RM, Vinay L, Brocard F. Sensitization of neonatal rat lumbar motoneuron by the inflammatory pain mediator bradykinin. eLife 2015; 4:e06195. [PMID: 25781633 PMCID: PMC4410746 DOI: 10.7554/elife.06195] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 03/16/2015] [Indexed: 11/27/2022] Open
Abstract
Bradykinin (Bk) is a potent inflammatory mediator that causes hyperalgesia. The action of Bk on the sensory system is well documented but its effects on motoneurons, the final pathway of the motor system, are unknown. By a combination of patch-clamp recordings and two-photon calcium imaging, we found that Bk strongly sensitizes spinal motoneurons. Sensitization was characterized by an increased ability to generate self-sustained spiking in response to excitatory inputs. Our pharmacological study described a dual ionic mechanism to sensitize motoneurons, including inhibition of a barium-sensitive resting K+ conductance and activation of a nonselective cationic conductance primarily mediated by Na+. Examination of the upstream signaling pathways provided evidence for postsynaptic activation of B2 receptors, G protein activation of phospholipase C, InsP3 synthesis, and calmodulin activation. This study questions the influence of motoneurons in the assessment of hyperalgesia since the withdrawal motor reflex is commonly used as a surrogate pain model. DOI:http://dx.doi.org/10.7554/eLife.06195.001 When we accidentally place our hand on a hot stove, we normally experience a painful sensation that starts with the sensory nerves under our skin. These nerves respond by transmitting electrical impulses to our brain, where the painful sensation is then processed. At the same time, these impulses are also transmitted to the motor nerves that control the muscles in our hand to trigger an immediate reflex to withdraw the hand from the hot stove. Pain therefore has a useful role as it can reduce how bad an injury is. People with a condition called hyperalgesia have an increased sensitivity to pain. This condition can result from a chemical called bradykinin ‘sensitizing’ the sensory nerves, causing them to transmit more electrical impulses in response to pain than normal. This makes the injury feel much more painful, and can make the pain last for longer than is beneficial. It was less clear whether bradykinin also affects motor nerves and so triggers a withdrawal reflex. By recording the electrical activity of motor nerve cells taken from the spinal cords of newborn rats, Bouhadfane et al. now show that these motor nerves become more active when exposed to bradykinin. Nerve cells generate electrical signals when ions—such as potassium, sodium, and calcium ions—move through channels in the membranes of the cell. Therefore, to investigate how bradykinin influences the electrical activity of motor nerves, Bouhadfane et al. exposed the cells to drugs that inhibit particular ion channels. This revealed that bradykinin sensitizes the motor nerves by blocking a type of potassium ion channel and activating another ion channel that mainly transports sodium ions. Furthermore, Bouhadfane et al. were able to identify the signaling pathways that allow bradykinin to affect the motor nerve cells. The study implies that the neuronal circuitry for pain does not rely exclusively on sensory nerve cells but should also integrate motor nerve cells. A future challenge remains in developing a protocol to resolve the contribution of motor nerve cells to hyperalgesia assessed by reflex withdrawal. DOI:http://dx.doi.org/10.7554/eLife.06195.002
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Affiliation(s)
- Mouloud Bouhadfane
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Attila Kaszás
- Institut de Neuroscience des Systèmes (UMR1106), Aix Marseille Université and INSERM, Marseille, France
| | - Balázs Rózsa
- Two-Photon Imaging Center, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Laurent Vinay
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Frédéric Brocard
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
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Jin X, Shah S, Du X, Zhang H, Gamper N. Activation of Ca(2+) -activated Cl(-) channel ANO1 by localized Ca(2+) signals. J Physiol 2014; 594:19-30. [PMID: 25398532 PMCID: PMC4704509 DOI: 10.1113/jphysiol.2014.275107] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/08/2014] [Indexed: 12/13/2022] Open
Abstract
Ca2+‐activated chloride channels (CaCCs) regulate numerous physiological processes including epithelial transport, smooth muscle contraction and sensory processing. Anoctamin‐1 (ANO1, TMEM16A) is a principal CaCC subunit in many cell types, yet our understanding of the mechanisms of ANO1 activation and regulation are only beginning to emerge. Ca2+ sensitivity of ANO1 is rather low and at negative membrane potentials the channel requires several micromoles of intracellular Ca2+ for activation. However, global Ca2+ levels in cells rarely reach such levels and, therefore, there must be mechanisms that focus intracellular Ca2+ transients towards the ANO1 channels. Recent findings indeed indicate that ANO1 channels often co‐localize with sources of intracellular Ca2+ signals. Interestingly, it appears that in many cell types ANO1 is particularly tightly coupled to the Ca2+ release sites of the intracellular Ca2+ stores. Such preferential coupling may represent a general mechanism of ANO1 activation in native tissues.
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Affiliation(s)
- Xin Jin
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Sihab Shah
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Xiaona Du
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
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Abstract
In the 30 years since IP3 (inositol 1,4,5-trisphosphate) was first shown to release Ca2+ from intracellular stores, the importance of spatially organized interactions within IP3-regulated signalling pathways has been universally recognized. Recent evidence that addresses three different levels of the structural determinants of IP3-evoked Ca2+ signalling is described in the present review. High-resolution structures of the N-terminal region of the IP3R (IP3 receptor) have established that the two essential phosphate groups of IP3 bind to opposite sides of the IP3-binding site, pulling its two domains together. This conformational change is proposed to disrupt an interaction between adjacent subunits within the tetrameric IP3R that normally holds the channel in a closed state. Similar structural changes are thought to allow gating of ryanodine receptors. cAMP increases the sensitivity of IP3Rs and thereby potentiates the Ca2+ signals evoked by receptors that stimulate IP3 formation. We speculate that both IP3 and cAMP are delivered to IP3Rs within signalling junctions, wherein the associated IP3Rs are exposed to a saturating concentration of either messenger. The concentration-dependent effects of extracellular stimuli come from recruitment of junctions rather than from a graded increase in the activity of individual junctions. IP3Rs within 'IP3 junctions' respond directly to receptors that stimulate phospholipase C, whereas extra-junctional IP3Rs are exposed to suboptimal concentrations of IP3 and open only when they are sensitized by cAMP. These results highlight the importance of selective delivery of diffusible messengers to IP3Rs. The spatial organization of IP3Rs also allows them to direct Ca2+ to specific intracellular targets that include other IP3Rs, mitochondria and Ca2+-regulated channels and enzymes. IP3Rs also interact functionally with lysosomes because Ca2+ released by IP3Rs, but not that entering cells via store-operated Ca2+ entry pathways, is selectively accumulated by lysosomes. This Ca2+ uptake shapes the Ca2+ signals evoked by IP3 and it may regulate lysosomal behaviour.
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Characterization of novel store-operated calcium entry effectors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2341-7. [PMID: 24657813 DOI: 10.1016/j.bbamcr.2014.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/14/2014] [Accepted: 03/12/2014] [Indexed: 01/29/2023]
Abstract
2-Aminoethyl diphenylborinate (2-APB) is a well-known effector of the store-operated Ca(2+) entry of several cell types such as immune cells, platelets and smooth muscle cells. 2-APB has a dual effect: potentiation at 1-5μM and inhibition at >30μM. Unfortunately, it is also able to modify the activity of other Ca(2+) transporters and, thus, cannot be used as a therapeutic tool to control the leukocyte activity in diseases like inflammation. Previously, we have shown that SOCE potentiation by 2-APB depends on the presence of the central boron-oxygen core (BOC) and that the phenyl groups determine the sensitivity of the molecule to inhibit and/or potentiate the SOCE. We hypothesized that by modifying the two phenyl groups of 2-APB, we could identify more efficient and specific analogues. In fact, the addition of methoxyl groups to one phenyl group greatly decreased the potentiation ability without any significant effect on the inhibition. Surprisingly, when the free rotation of the two phenyl groups was blocked by a new hydrocarbon bridge, the BOC was no longer able to potentiate. Furthermore, larger aryl groups than phenyl also impaired the activity of the BOC. Thus, the potentiation site in the Ca(2+) channel is not accessible by the BOC when the lateral groups are too large or unable to freely rotate. However, these molecules are potent inhibitors of store-operated calcium entry with affinities below 1μM, and they can block the activation of the Jurkat T cells. Thus, it is possible to characterize 2-APB analogues with different properties that could be the first step in the discovery of new immunomodulators. This article is part of a special issue entitled "Calcium Signaling in Health and Disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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McCarron JG, Olson ML, Wilson C, Sandison ME, Chalmers S. Examining the role of mitochondria in Ca²⁺ signaling in native vascular smooth muscle. Microcirculation 2013; 20:317-29. [PMID: 23305516 PMCID: PMC3708117 DOI: 10.1111/micc.12039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 01/07/2013] [Indexed: 01/18/2023]
Abstract
Mitochondrial Ca2+ uptake contributes important feedback controls to limit the time course of Ca2+signals. Mitochondria regulate cytosolic [Ca2+] over an exceptional breath of concentrations (∼200 nM to >10 μM) to provide a wide dynamic range in the control of Ca2+ signals. Ca2+ uptake is achieved by passing the ion down the electrochemical gradient, across the inner mitochondria membrane, which itself arises from the export of protons. The proton export process is efficient and on average there are less than three protons free within the mitochondrial matrix. To study mitochondrial function, the most common approaches are to alter the proton gradient and to measure the electrochemical gradient. However, drugs which alter the mitochondrial proton gradient may have substantial off target effects that necessitate careful consideration when interpreting their effect on Ca2+ signals. Measurement of the mitochondrial electrochemical gradient is most often performed using membrane potential sensitive fluorophores. However, the signals arising from these fluorophores have a complex relationship with the electrochemical gradient and are altered by changes in plasma membrane potential. Care is again needed in interpreting results. This review provides a brief description of some of the methods commonly used to alter and measure mitochondrial contribution to Ca2+ signaling in native smooth muscle.
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Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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Russino D, McDonald E, Hejazi L, Hanson GR, Jones CE. The tachykinin peptide neurokinin B binds copper forming an unusual [CuII(NKB)2] complex and inhibits copper uptake into 1321N1 astrocytoma cells. ACS Chem Neurosci 2013; 4:1371-81. [PMID: 23875773 DOI: 10.1021/cn4000988] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Neurokinin B (NKB) is a member of the tachykinin family of neuropeptides that have neuroinflammatory, neuroimmunological, and neuroprotective functions. In a neuroprotective role, tachykinins can help protect cells against the neurotoxic processes observed in Alzheimer's disease. A change in copper homeostasis is a clear feature of Alzheimer's disease, and the dysregulation may be a contributory factor in toxicity. Copper has recently been shown to interact with neurokinin A and neuropeptide γ and can lead to generation of reactive oxygen species and peptide degradation, which suggests that copper may have a place in tachykinin function and potentially misfunction. To explore this, we have utilized a range of spectroscopic techniques to show that NKB, but not substance P, can bind Cu(II) in an unusual [Cu(II)(NKB)2] neutral complex that utilizes two N-terminal amine and two imidazole nitrogen ligands (from each molecule of NKB) and the binding substantially alters the structure of the peptide. Using 1321N1 astrocytoma cells, we show that copper can enter the cells and subsequently open plasma membrane calcium channels but when bound to neurokinin B copper ion uptake is inhibited. This data suggests a novel role for neurokinin B in protecting cells against copper-induced calcium changes and implicates the peptide in synaptic copper homeostasis.
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Affiliation(s)
- Debora Russino
- The School of Science
and Health, The University of Western Sydney, Locked bag 1797, Penrith, New South Wales 2759, Australia
| | - Elle McDonald
- The School of Science
and Health, The University of Western Sydney, Locked bag 1797, Penrith, New South Wales 2759, Australia
| | - Leila Hejazi
- Mass Spectroscopy Laboratory, The University of Western Sydney, Locked bag 1797,
Penrith, New South Wales 2759, Australia
| | - Graeme R. Hanson
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christopher E. Jones
- The School of Science
and Health, The University of Western Sydney, Locked bag 1797, Penrith, New South Wales 2759, Australia
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The actions of Pasteurella multocida toxin on neuronal cells. Neuropharmacology 2013; 77:9-18. [PMID: 24055502 PMCID: PMC3878393 DOI: 10.1016/j.neuropharm.2013.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 02/06/2023]
Abstract
Pasteurella multocida toxin (PMT) activates the G-proteins Gαi(1-3), Gαq, Gα11, Gα12 and Gα13 by deamidation of specific glutamine residues. A number of these alpha subunits have signalling roles in neurones. Hence we studied the action of this toxin on rat superior cervical ganglion (SCG) neurones and NG108-15 neuronal cells. Both Gαq and Gα11 could be identified in SCGs with immunocytochemistry. PMT had no direct action on Kv7 or Cav2 channels in SCGs. However PMT treatment enhanced muscarinic receptor mediated inhibition of M-current (Kv7.2 + 7. 3) as measured by a 19-fold leftward shift in the oxotremorine-M concentration–inhibition curve. Agonists of other receptors, such as bradykinin or angiotensin, that inhibit M-current did not produce this effect. However the amount of PIP2 hydrolysis could be enhanced by PMT for all three agonists. In a transduction system in SCGs that is unlikely to be affected by PMT, Go mediated inhibition of calcium current, PMT was ineffective whereas the response was blocked by pertussis toxin as expected. M1 muscarinic receptor evoked calcium mobilisation in transformed NG108-15 cells was enhanced by PMT. The calcium rises evoked by uridine triphosphate acting on endogenous P2Y2 receptors in NG108-15 cells were enhanced by PMT. The time and concentration dependence of the PMT effect was different for the resting calcium compared to the calcium rise produced by activation of P2Y2 receptors. PMT's action on these neuronal cells would suggest that if it got into the brain, symptoms of a hyperexcitable nature would be seen, such as seizures. Pasteurella multocida toxin (PMT) activates a range of G-protein alpha subunits. PMT increased muscarinic receptor mediated suppression of Kv7 potassium current in sympathetic neurones. PMT enhances both muscarinic and purinergic receptor mediated calcium mobilisation in NG108-15 cells. Both these events are mediated by the G-proteins Gq or G11. We would predict that the symptoms of central nervous system PMT toxicity would be hyperexcitable events such as seizures.
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Zhang H, Liu Y, Xu J, Zhang F, Liang H, Du X, Zhang H. Membrane microdomain determines the specificity of receptor-mediated modulation of Kv7/M potassium currents. Neuroscience 2013; 254:70-9. [PMID: 24036375 DOI: 10.1016/j.neuroscience.2013.08.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 01/18/2023]
Abstract
The Kv7/M current is one of the major mechanisms controlling neuronal excitability, which can be modulated by activation of the G protein-coupled receptor (GPCR) via distinct signaling pathways. Membrane microdomains known as lipid rafts have been implicated in the specificity of various cell signaling pathways. The aim of this study was to understand the role of lipid rafts in the specificity of Kv7/M current modulation by activation of GPCR. Methyl-β-cyclodextrin (MβCD), often used to disrupt the integrity of lipid rafts, significantly reduced the bradykinin receptor (B2R)-induced but not muscarinic receptor (M1R)-induced inhibition of the Kv7/M current. B2R and related signaling molecules but not M1R were found in caveolin-containing raft fractions of the rat superior cervical ganglia. Furthermore, activation of B2R resulted in translocation of additional B2R into the lipid rafts, which was not observed for the activation of M1R. The increase of B2R-induced intracellular Ca(2+) was also greatly reduced after MβCD treatment. Finally, B2R but not M1R was found to interact with the IP3 receptor. In conclusion, the present study implicates an important role for lipid rafts in mediating specificity for GPCR-mediated inhibition of the Kv7/M current.
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Affiliation(s)
- H Zhang
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, Hebei Province, China; The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, Hebei Province, China; Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei Province, China
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Jin X, Shah S, Liu Y, Zhang H, Lees M, Fu Z, Lippiat JD, Beech DJ, Sivaprasadarao A, Baldwin SA, Zhang H, Gamper N. Activation of the Cl- channel ANO1 by localized calcium signals in nociceptive sensory neurons requires coupling with the IP3 receptor. Sci Signal 2013; 6:ra73. [PMID: 23982204 DOI: 10.1126/scisignal.2004184] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report that anoctamin 1 (ANO1; also known as TMEM16A) Ca(2+)-activated Cl(-) channels in small neurons from dorsal root ganglia are preferentially activated by particular pools of intracellular Ca(2+). These ANO1 channels can be selectively activated by the G protein-coupled receptor (GPCR)-induced release of Ca(2+) from intracellular stores but not by Ca(2+) influx through voltage-gated Ca(2+) channels. This ability to discriminate between Ca(2+) pools was achieved by the tethering of ANO1-containing plasma membrane domains, which also contained GPCRs such as bradykinin receptor 2 and protease-activated receptor 2, to juxtamembrane regions of the endoplasmic reticulum. Interaction of the carboxyl terminus and the first intracellular loop of ANO1 with IP3R1 (inositol 1,4,5-trisphosphate receptor 1) contributed to the tethering. Disruption of membrane microdomains blocked the ANO1 and IP3R1 interaction and resulted in the loss of coupling between GPCR signaling and ANO1. The junctional signaling complex enabled ANO1-mediated excitation in response to specific Ca(2+)signals rather than to global changes in intracellular Ca(2+).
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Affiliation(s)
- Xin Jin
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
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Isoform- and receptor-specific channel property of canonical transient receptor potential (TRPC)1/4 channels. Pflugers Arch 2013; 466:491-504. [DOI: 10.1007/s00424-013-1332-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/29/2013] [Accepted: 07/29/2013] [Indexed: 10/26/2022]
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Bradykinin B₂ receptors increase hippocampal excitability and susceptibility to seizures in mice. Neuroscience 2013; 248:392-402. [PMID: 23811399 DOI: 10.1016/j.neuroscience.2013.06.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 12/23/2022]
Abstract
Bradykinin (BK) and its receptors (B1 and B2) may exert a role in the pathophysiology of certain CNS diseases, including epilepsy. In healthy tissues, B2 receptors are constitutively and widely expressed and B1 receptors are absent or expressed at very low levels, but both receptors, particularly B1, are up-regulated under many pathological conditions. Available data support the notion that up-regulation of B1 receptors in brain areas like the amygdala, hippocampus and entorhinal cortex favors the development and maintenance of an epileptic condition. The role of B2 receptors, instead, is still unclear. In this study, we used two different models to investigate the susceptibility to seizures of B1 knockout (KO) and B2 KO mice. We found that B1 KO are more susceptible to seizures compared with wild-type (WT) mice, and that this may depend on B2 receptors, in that (i) B2 receptors are overexpressed in limbic areas of B1 KO mice, including the hippocampus and the piriform cortex; (ii) hippocampal slices prepared from B1 KO mice are more excitable than those prepared from WT controls, and this phenomenon is B2 receptor-dependent, being abolished by B2 antagonists; (iii) kainate seizure severity is attenuated by pretreatment with a non-peptide B2 antagonist in WT and (more effectively) in B1 KO mice. These data highlight the possibility that B2 receptors may have a role in the responsiveness to epileptogenic insults and/or in the early period of epileptogenesis, that is, in the onset of the molecular and cellular events that lead to the transformation of a normal brain into an epileptic one.
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Effects of protease-activated receptors (PARs) on intracellular calcium dynamics of acinar cells in rat lacrimal glands. Histochem Cell Biol 2013; 140:463-76. [PMID: 23463389 DOI: 10.1007/s00418-013-1082-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2013] [Indexed: 10/27/2022]
Abstract
Protease-activated receptors (PARs) represent a novel class of seven transmembrane domain G-protein coupled receptors, which are activated by proteolytic cleavage. PARs are present in a variety of cells and have been prominently implicated in the regulation of a number of vital functions. Here, lacrimal gland acinar cell responses to PAR activation were examined, with special reference to intracellular Ca(2+) concentration ([Ca(2+)]i) dynamics. In the present study, detection of acinar cell mRNA specific to known PAR subtypes was determined by reverse transcriptase polymerase chain reaction. Only PAR2 mRNA was detected in acinar cells of lacrimal glands. Both trypsin and a PAR2-activating peptide (PAR2-AP), SLIGRL-NH2, induced an increase in [Ca(2+)]i in acinar cells. The removal of extracellular Ca(2+) and the use of Ca(2+) channel blockers did not inhibit PAR2-AP-induced [Ca(2+)]i increases. Furthermore, U73122 and xestospongin C failed to inhibit PAR2-induced increases in [Ca(2+)]i. The origin of the calcium influx observed after activated PAR2-induced Ca(2+) release from intracellular Ca(2+) stores was also evaluated. The NO donor, GEA 3162, mimicked the effects of PAR2 in activating non-capacitative calcium entry (NCCE). However, both calyculin A (100 nM) and a low concentration of Gd(3+) (5 μM) did not completely block the PAR2-AP-induced increase in [Ca(2+)]i. These findings indicated that PAR2 activation resulted primarily in Ca(2+) mobilization from intracellular Ca(2+) stores and that PAR2-mediated [Ca(2+)]i changes were mainly independent of IP3. RT-PCR indicated that TRPC 1, 3 and 6, which play a role in CCE and NCCE, are expressed in acinar cells. We suggest that PAR2-AP differentially regulates both NCCE and CCE, predominantly NCCE. Finally, our results suggested that PAR2 may function as a key receptor in calcium-related cell homeostasis under pathophysiological conditions such as tissue injury or inflammation.
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The Other (Muscarinic) Acetylcholine Receptors in Sympathetic Ganglia: Actions and Mechanisms. NEUROPHYSIOLOGY+ 2013. [DOI: 10.1007/s11062-013-9337-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Phospholipase C (PLC) converts phosphatidylinositol 4,5-bisphosphate (PIP(2)) to inositol 1,4,5-trisphosphate (IP(3)) and diacylglycerol (DAG). DAG and IP(3) each control diverse cellular processes and are also substrates for synthesis of other important signaling molecules. PLC is thus central to many important interlocking regulatory networks. Mammals express six families of PLCs, each with both unique and overlapping controls over expression and subcellular distribution. Each PLC also responds acutely to its own spectrum of activators that includes heterotrimeric G protein subunits, protein tyrosine kinases, small G proteins, Ca(2+), and phospholipids. Mammalian PLCs are autoinhibited by a region in the catalytic TIM barrel domain that is the target of much of their acute regulation. In combination, the PLCs act as a signaling nexus that integrates numerous signaling inputs, critically governs PIP(2) levels, and regulates production of important second messengers to determine cell behavior over the millisecond to hour timescale.
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Affiliation(s)
- Ganesh Kadamur
- Department of Pharmacology, Molecular Biophysics Graduate Program and Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Zamponi GW, Currie KPM. Regulation of Ca(V)2 calcium channels by G protein coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1629-43. [PMID: 23063655 DOI: 10.1016/j.bbamem.2012.10.004] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/02/2012] [Accepted: 10/04/2012] [Indexed: 12/29/2022]
Abstract
Voltage gated calcium channels (Ca²⁺ channels) are key mediators of depolarization induced calcium influx into excitable cells, and thereby play pivotal roles in a wide array of physiological responses. This review focuses on the inhibition of Ca(V)2 (N- and P/Q-type) Ca²⁺-channels by G protein coupled receptors (GPCRs), which exerts important autocrine/paracrine control over synaptic transmission and neuroendocrine secretion. Voltage-dependent inhibition is the most widespread mechanism, and involves direct binding of the G protein βγ dimer (Gβγ) to the α1 subunit of Ca(V)2 channels. GPCRs can also recruit several other distinct mechanisms including phosphorylation, lipid signaling pathways, and channel trafficking that result in voltage-independent inhibition. Current knowledge of Gβγ-mediated inhibition is reviewed, including the molecular interactions involved, determinants of voltage-dependence, and crosstalk with other cell signaling pathways. A summary of recent developments in understanding the voltage-independent mechanisms prominent in sympathetic and sensory neurons is also included. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- Gerald W Zamponi
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, University of Calgary, Canada
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Olson ML, Sandison ME, Chalmers S, McCarron JG. Microdomains of muscarinic acetylcholine and Ins(1,4,5)P₃ receptors create 'Ins(1,4,5)P₃ junctions' and sites of Ca²+ wave initiation in smooth muscle. J Cell Sci 2012; 125:5315-28. [PMID: 22946060 PMCID: PMC3561854 DOI: 10.1242/jcs.105163] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Increases in cytosolic Ca2+ concentration ([Ca2+]c) mediated by inositol (1,4,5)-trisphosphate [Ins(1,4,5)P3, hereafter InsP3] regulate activities that include division, contraction and cell death. InsP3-evoked Ca2+ release often begins at a single site, then regeneratively propagates through the cell as a Ca2+ wave. The Ca2+ wave consistently begins at the same site on successive activations. Here, we address the mechanisms that determine the Ca2+ wave initiation site in intestinal smooth muscle cells. Neither an increased sensitivity of InsP3 receptors (InsP3R) to InsP3 nor regional clustering of muscarinic receptors (mAChR3) or InsP3R1 explained the selection of an initiation site. However, examination of the overlap of mAChR3 and InsP3R1 localisation, by centre of mass analysis, revealed that there was a small percentage (∼10%) of sites that showed colocalisation. Indeed, the extent of colocalisation was greatest at the Ca2+ wave initiation site. The initiation site might arise from a selective delivery of InsP3 from mAChR3 activity to particular InsP3Rs to generate faster local [Ca2+]c increases at sites of colocalisation. In support of this hypothesis, a localised subthreshold ‘priming’ InsP3 concentration applied rapidly, but at regions distant from the initiation site, shifted the wave to the site of the priming. Conversely, when the Ca2+ rise at the initiation site was rapidly and selectively attenuated, the Ca2+ wave again shifted and initiated at a new site. These results indicate that Ca2+ waves initiate where there is a structural and functional coupling of mAChR3 and InsP3R1, which generates junctions in which InsP3 acts as a highly localised signal by being rapidly and selectively delivered to InsP3R1.
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Affiliation(s)
- Marnie L Olson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, The Arbuthnott Building, 161 Cathedral Street, Glasgow G4 0RE, UK
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MacMillan D, Kennedy C, McCarron JG. ATP inhibits Ins(1,4,5)P3-evoked Ca2+ release in smooth muscle via P2Y1 receptors. J Cell Sci 2012; 125:5151-8. [PMID: 22899721 PMCID: PMC5704898 DOI: 10.1242/jcs.108498] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Adenosine 5′-triphosphate (ATP) mediates a variety of biological functions following nerve-evoked release, via activation of either G-protein-coupled P2Y- or ligand-gated P2X receptors. In smooth muscle, ATP, acting via P2Y receptors (P2YR), may act as an inhibitory neurotransmitter. The underlying mechanism(s) remain unclear, but have been proposed to involve the production of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] by phospholipase C (PLC), to evoke Ca2+ release from the internal store and stimulation of Ca2+-activated potassium (KCa) channels to cause membrane hyperpolarization. This mechanism requires Ca2+ release from the store. However, in the present study, ATP evoked transient Ca2+ increases in only ~10% of voltage-clamped single smooth muscle cells. These results do not support activation of KCa as the major mechanism underlying inhibition of smooth muscle activity. Interestingly, ATP inhibited Ins(1,4,5)P3-evoked Ca2+ release in cells that did not show a Ca2+ rise in response to purinergic activation. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was not mimicked by adenosine and therefore, cannot be explained by hydrolysis of ATP to adenosine. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was, however, also observed with its primary metabolite, ADP, and blocked by the P2Y1R antagonist, MRS2179, and the G protein inhibitor, GDPβS, but not by PLC inhibition. The present study demonstrates a novel inhibitory effect of P2Y1R activation on Ins(1,4,5)P3-evoked Ca2+ release, such that purinergic stimulation acts to prevent Ins(1,4,5)P3-mediated increases in excitability in smooth muscle and promote relaxation.
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Affiliation(s)
- D MacMillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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Choveau FS, Abderemane-Ali F, Coyan FC, Es-Salah-Lamoureux Z, Baró I, Loussouarn G. Opposite Effects of the S4-S5 Linker and PIP(2) on Voltage-Gated Channel Function: KCNQ1/KCNE1 and Other Channels. Front Pharmacol 2012; 3:125. [PMID: 22787448 PMCID: PMC3389672 DOI: 10.3389/fphar.2012.00125] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/14/2012] [Indexed: 01/16/2023] Open
Abstract
Voltage-gated potassium (Kv) channels are tetramers, each subunit presenting six transmembrane segments (S1-S6), with each S1-S4 segments forming a voltage-sensing domain (VSD) and the four S5-S6 forming both the conduction pathway and its gate. S4 segments control the opening of the intracellular activation gate in response to changes in membrane potential. Crystal structures of several voltage-gated ion channels in combination with biophysical and mutagenesis studies highlighted the critical role of the S4-S5 linker (S4S5(L)) and of the S6 C-terminal part (S6(T)) in the coupling between the VSD and the activation gate. Several mechanisms have been proposed to describe the coupling at a molecular scale. This review summarizes the mechanisms suggested for various voltage-gated ion channels, including a mechanism that we described for KCNQ1, in which S4S5(L) is acting like a ligand binding to S6(T) to stabilize the channel in a closed state. As discussed in this review, this mechanism may explain the reverse response to depolarization in HCN-like channels. As opposed to S4S5(L), the phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP(2)), stabilizes KCNQ1 channel in an open state. Many other ion channels (not only voltage-gated) require PIP(2) to function properly, confirming its crucial importance as an ion channel cofactor. This is highlighted in cases in which an altered regulation of ion channels by PIP(2) leads to channelopathies, as observed for KCNQ1. This review summarizes the state of the art on the two regulatory mechanisms that are critical for KCNQ1 and other voltage-gated channels function (PIP(2) and S4S5(L)), and assesses their potential physiological and pathophysiological roles.
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Affiliation(s)
- Frank S Choveau
- UMR 1087, Institut National de la Santé et de la Recherche Médicale Nantes, France
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