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Bader A, Bintig W, Begandt D, Klett A, Siller IG, Gregor C, Schaarschmidt F, Weksler B, Romero I, Couraud PO, Hell SW, Ngezahayo A. Adenosine receptors regulate gap junction coupling of the human cerebral microvascular endothelial cells hCMEC/D3 by Ca 2+ influx through cyclic nucleotide-gated channels. J Physiol 2017; 595:2497-2517. [PMID: 28075020 DOI: 10.1113/jp273150] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 12/16/2016] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Gap junction channels are essential for the formation and regulation of physiological units in tissues by allowing the lateral cell-to-cell diffusion of ions, metabolites and second messengers. Stimulation of the adenosine receptor subtype A2B increases the gap junction coupling in the human blood-brain barrier endothelial cell line hCMEC/D3. Although the increased gap junction coupling is cAMP-dependent, neither the protein kinase A nor the exchange protein directly activated by cAMP were involved in this increase. We found that cAMP activates cyclic nucleotide-gated (CNG) channels and thereby induces a Ca2+ influx, which leads to the increase in gap junction coupling. The report identifies CNG channels as a possible physiological link between adenosine receptors and the regulation of gap junction channels in endothelial cells of the blood-brain barrier. ABSTRACT The human cerebral microvascular endothelial cell line hCMEC/D3 was used to characterize the physiological link between adenosine receptors and the gap junction coupling in endothelial cells of the blood-brain barrier. Expressed adenosine receptor subtypes and connexin (Cx) isoforms were identified by RT-PCR. Scrape loading/dye transfer was used to evaluate the impact of the A2A and A2B adenosine receptor subtype agonist 2-phenylaminoadenosine (2-PAA) on the gap junction coupling. We found that 2-PAA stimulated cAMP synthesis and enhanced gap junction coupling in a concentration-dependent manner. This enhancement was accompanied by an increase in gap junction plaques formed by Cx43. Inhibition of protein kinase A did not affect the 2-PAA-related enhancement of gap junction coupling. In contrast, the cyclic nucleotide-gated (CNG) channel inhibitor l-cis-diltiazem, as well as the chelation of intracellular Ca2+ with BAPTA, or the absence of external Ca2+ , suppressed the 2-PAA-related enhancement of gap junction coupling. Moreover, we observed a 2-PAA-dependent activation of CNG channels by a combination of electrophysiology and pharmacology. In conclusion, the stimulation of adenosine receptors in hCMEC/D3 cells induces a Ca2+ influx by opening CNG channels in a cAMP-dependent manner. Ca2+ in turn induces the formation of new gap junction plaques and a consecutive sustained enhancement of gap junction coupling. The report identifies CNG channels as a physiological link that integrates gap junction coupling into the adenosine receptor-dependent signalling of endothelial cells of the blood-brain barrier.
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Affiliation(s)
- Almke Bader
- Institute of Biophysics, Leibniz University Hannover, Hannover, Germany
| | - Willem Bintig
- Institute of Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Daniela Begandt
- Walter Brendel Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Anne Klett
- Institute of Biophysics, Leibniz University Hannover, Hannover, Germany
| | - Ina G Siller
- Institute of Biophysics, Leibniz University Hannover, Hannover, Germany
| | - Carola Gregor
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - Babette Weksler
- Weill Medical College of Cornell University, New York, NY, USA
| | - Ignacio Romero
- Department of Biological Sciences, The Open University, Walton Hall, Milton Keynes, UK
| | - Pierre-Olivier Couraud
- INSERM, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Paris, France
| | - Stefan W Hell
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Anaclet Ngezahayo
- Institute of Biophysics, Leibniz University Hannover, Hannover, Germany.,Center for Systems Neuroscience Hannover, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
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Chen M, Li J, Jiang F, Fu J, Xia X, Du J, Hu M, Huang J, Shen B. Orai1 forms a signal complex with BKCa channel in mesenteric artery smooth muscle cells. Physiol Rep 2016; 4:4/1/e12682. [PMID: 26755740 PMCID: PMC4760400 DOI: 10.14814/phy2.12682] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Orai1, a specific nonvoltage‐gated Ca2+ channel, has been found to be one of key molecules involved in store‐operated Ca2+ entry (SOCE). Orai1 may associate with other proteins to form a signaling complex, which is essential for regulating a variety of physiological functions. In this study, we studied the possible interaction between Orai1 and large conductance Ca2+‐activated potassium channel (BKCa). Using RNA interference technique, we demonstrated that the SOCE and its associated membrane hyperpolarization were markedly suppressed after knockdown of Orai1 with a specific Orai1 siRNA in rat mesenteric artery smooth muscle. Moreover, isometric tension measurements showed that agonist‐induced vasocontraction was increased after Orai1 was knocked down or the tissue was incubated with BKCa blocker iberiotoxin. Coimmunoprecipitation data revealed that BKCa and Orai1 could reciprocally pull down each other. In situ proximity ligation assay further demonstrated that Orai1 and BKCa are in close proximity. Taken together, these results indicate that Orai1 physically associates with BKCa to form a signaling complex in the rat mesenteric artery smooth muscle. Ca2+ influx via Orai1 stimulates BKCa, leading to membrane hyperpolarization. This hyperpolarizing effect of Orai1‐BKCa coupling could contribute to reduce agonist‐induced membrane depolarization, therefore preventing excessive contraction of the rat mesenteric artery smooth muscle in response to contractile agonists.
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Affiliation(s)
- Meihua Chen
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Jie Li
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Feifei Jiang
- Department of Pediatrics, The people's hospital of Bozhou, Bozhou, Anhui, China
| | - Jie Fu
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Xianming Xia
- Department of Gastroenterology and Hepatology, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Juan Du
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China
| | - Min Hu
- Department of Sports and Health, Guangdong Provincial Key Laboratory of Sports and Health Promotion, Guangzhou Sport University, Guangzhou, Guangdong, China
| | - Junhao Huang
- Department of Sports and Health, Guangdong Provincial Key Laboratory of Sports and Health Promotion, Guangzhou Sport University, Guangzhou, Guangdong, China
| | - Bing Shen
- Department of Physiology, Anhui Medical University, Hefei, Anhui, China Central Laboratory of Molecular and Cellular Biology of School of Basic Medicine, Anhui Medical University, Hefei, Anhui, China
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Chen Y, Yang W, Li X, Li X, Yang H, Xu Z, Yu S. α-Synuclein-induced internalization of NMDA receptors in hippocampal neurons is associated with reduced inward current and Ca(2+) influx upon NMDA stimulation. Neuroscience 2015; 300:297-306. [PMID: 26003734 DOI: 10.1016/j.neuroscience.2015.05.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/26/2015] [Accepted: 05/14/2015] [Indexed: 01/21/2023]
Abstract
Abnormal α-synuclein (α-syn) expression and aggregation have been implicated in the pathogenesis of Parkinson's disease (PD), dementia with Lewy bodies (DLB), and Alzheimer's disease (AD). These neurodegenerative disorders, collectively known as synucleinopathies, are usually associated with cognitive impairment that could be caused by impaired hippocampal function. Although abnormal expressions of α-syn and N-methyl-d-aspartate (NMDA) receptor are frequently observed in the hippocampus of patients with synucleinopathies, how these proteins interact with each other in hippocampal neurons remains poorly understood. In the present study, primary cultures of hippocampal neurons and α-syn transgenic mice were used to investigate the effect of α-syn on NMDA receptors. Neurons were treated either by direct addition of recombinant human α-syn (hα-syn) to the medium, or by infection with the hα-syn gene, to increase intracellular levels of α-syn. In both cases, NMDA receptor NR1 subunits on the cell surface were reduced while the total amount of NR1 was unchanged, indicating an internalization of NR1 subunits. Neurons with elevated α-syn also showed a profound increase in Rab5B, an isoform of the small GTPases essential for NMDA receptor endocytosis. Knockdown of Rab5B expression by siRNA inhibited the α-syn-induced reduction in surface NR1. The in vitro findings were confirmed in α-syn transgenic mice, showing that increased α-syn expression was accompanied by reduced levels of surface NR1 and increased expression of Rab5B. Due to the essential role of NR1 subunits for assembling a complete NMDA receptor, its reduction on the cell surface indicated impaired receptor function. This was demonstrated by observations that neurons with elevated α-syn showed profound reductions in NMDA-elicited Ca(2+) influx and inward current, which were also inhibited by knockdown of Rab5B expression. Our data suggest that increased α-syn expression may impair NMDA receptor function in the hippocampus by reducing the density of NR1 subunits on the cell surface.
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Affiliation(s)
- Y Chen
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - W Yang
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - X Li
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - X Li
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - H Yang
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China; Beijing Institute for Brain Disorders Parkinson's Disease Center, Beijing, China
| | - Z Xu
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China; Beijing Institute for Brain Disorders Parkinson's Disease Center, Beijing, China
| | - S Yu
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing, China; Beijing Institute for Brain Disorders Parkinson's Disease Center, Beijing, China.
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Maimon N, Titus PA, Sarelius IH. Pre-exposure to adenosine, acting via A(2A) receptors on endothelial cells, alters the protein kinase A dependence of adenosine-induced dilation in skeletal muscle resistance arterioles. J Physiol 2014; 592:2575-90. [PMID: 24687580 DOI: 10.1113/jphysiol.2013.265835] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Adenosine (ADO) is an endogenous vasodilatory purine widely recognized to be a significant contributor to functional hyperaemia. Despite this, many aspects of the mechanisms by which ADO induces dilation in small resistance arterioles are not established, or appear contradictory. These include: identification of the primary receptor subtype; its location on endothelial (EC) or vascular smooth muscle cells; whether ADO acts on KATP channels in these resistance vessels; and the contribution of cAMP/protein kinase A (PKA) signalling to the response. In intravital microscopy studies of intact or EC-denuded skeletal muscle arterioles, we show that ADO acts via A2A receptors located on ECs to produce vasodilation via activation of KATP channels located on vascular smooth muscle cells. Importantly, we found that the signalling pathway involves cAMP as expected, but that a requirement for PKA activation is demonstrable only if the vessel is not pre-exposed to ADO. That is, PKA-dependent signalling varies with pre-exposure to ADO. Further, we show that PKA activation alone is not sufficient to dilate these arterioles; an additional EC calcium-dependent signalling mechanism is required for vasodilation to ADO. The ability of arterioles in situ to respond to occupancy of a specific receptor by utilizing different cell signalling pathways under different conditions to produce the same response allows the arteriole to respond to key homeostatic requirements using more than a single signalling mechanism. Clearly, this is likely to be physiologically advantageous, but the role for this signalling flexibility in the integrated arteriolar response that underlies functional hyperaemia will require further exploration.
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Affiliation(s)
- Nir Maimon
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Patricia A Titus
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Ingrid H Sarelius
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
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Burnstock G, Ralevic V. Purinergic signaling and blood vessels in health and disease. Pharmacol Rev 2013; 66:102-92. [PMID: 24335194 DOI: 10.1124/pr.113.008029] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; and Department of Pharmacology, The University of Melbourne, Australia.
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Roberts OL, Kamishima T, Barrett-Jolley R, Quayle JM, Dart C. Exchange protein activated by cAMP (Epac) induces vascular relaxation by activating Ca2+-sensitive K+ channels in rat mesenteric artery. J Physiol 2013; 591:5107-23. [PMID: 23959673 DOI: 10.1113/jphysiol.2013.262006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Vasodilator-induced elevation of intracellular cyclic AMP (cAMP) is a central mechanism governing arterial relaxation but is incompletely understood due to the diversity of cAMP effectors. Here we investigate the role of the novel cAMP effector exchange protein directly activated by cAMP (Epac) in mediating vasorelaxation in rat mesenteric arteries. In myography experiments, the Epac-selective cAMP analogue 8-pCPT-2-O-Me-cAMP-AM (5 μM, subsequently referred to as 8-pCPT-AM) elicited a 77.6 ± 7.1% relaxation of phenylephrine-contracted arteries over a 5 min period (mean ± SEM; n = 6). 8-pCPT-AM induced only a 16.7 ± 2.4% relaxation in arteries pre-contracted with high extracellular K(+) over the same time period (n = 10), suggesting that some of Epac's relaxant effect relies upon vascular cell hyperpolarization. This involves Ca(2+)-sensitive, large-conductance K(+) (BK(Ca)) channel opening as iberiotoxin (100 nM) significantly reduced the ability of 8-pCPT-AM to reverse phenylephrine-induced contraction (arteries relaxed by only 35.0 ± 8.5% over a 5 min exposure to 8-pCPT-AM, n = 5; P < 0.05). 8-pCPT-AM increased Ca(2+) spark frequency in Fluo-4-AM-loaded mesenteric myocytes from 0.045 ± 0.008 to 0.103 ± 0.022 sparks s(-1) μm(-1) (P < 0.05) and reversibly increased both the frequency (0.94 ± 0.25 to 2.30 ± 0.72 s(-1)) and amplitude (23.9 ± 3.3 to 35.8 ± 7.7 pA) of spontaneous transient outward currents (STOCs) recorded in isolated mesenteric myocytes (n = 7; P < 0.05). 8-pCPT-AM-activated STOCs were sensitive to iberiotoxin (100 nM) and to ryanodine (30 μM). Current clamp recordings of isolated myocytes showed a 7.9 ± 1.0 mV (n = 10) hyperpolarization in response to 8-pCPT-AM that was sensitive to iberiotoxin (n = 5). Endothelial disruption suppressed 8-pCPT-AM-mediated relaxation in phenylephrine-contracted arteries (24.8 ± 4.9% relaxation after 5 min of exposure, n = 5; P < 0.05), as did apamin and TRAM-34, blockers of Ca(2+)-sensitive, small- and intermediate-conductance K(+) (SK(Ca) and IK(Ca)) channels, respectively, and N(G)-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase (NOS). In Fluo-4-AM-loaded mesenteric endothelial cells, 8-pCPT-AM induced a sustained increase in global Ca(2+). Our data suggest that Epac hyperpolarizes smooth muscle by (1) increasing localized Ca(2+) release from ryanodine receptors (Ca(2+) sparks) to activate BK(Ca) channels, and (2) endothelial-dependent mechanisms involving the activation of SK(Ca)/IK(Ca) channels and NOS. Epac-mediated smooth muscle hyperpolarization will limit Ca(2+) entry via voltage-sensitive Ca(2+) channels and represents a novel mechanism of arterial relaxation.
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Affiliation(s)
- Owain Llŷr Roberts
- C. Dart: Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
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Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
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Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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Millstein J, Winrow CJ, Kasarskis A, Owens JR, Zhou L, Summa KC, Fitzpatrick K, Zhang B, Vitaterna MH, Schadt EE, Renger JJ, Turek FW. Identification of causal genes, networks, and transcriptional regulators of REM sleep and wake. Sleep 2011; 34:1469-77. [PMID: 22043117 DOI: 10.5665/sleep.1378] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVE Sleep-wake traits are well-known to be under substantial genetic control, but the specific genes and gene networks underlying primary sleep-wake traits have largely eluded identification using conventional approaches, especially in mammals. Thus, the aim of this study was to use systems genetics and statistical approaches to uncover the genetic networks underlying 2 primary sleep traits in the mouse: 24-h duration of REM sleep and wake. DESIGN Genome-wide RNA expression data from 3 tissues (anterior cortex, hypothalamus, thalamus/midbrain) were used in conjunction with high-density genotyping to identify candidate causal genes and networks mediating the effects of 2 QTL regulating the 24-h duration of REM sleep and one regulating the 24-h duration of wake. SETTING Basic sleep research laboratory. PATIENTS OR PARTICIPANTS Male [C57BL/6J × (BALB/cByJ × C57BL/6J*) F1] N(2) mice (n = 283). INTERVENTIONS None. MEASUREMENTS AND RESULTS The genetic variation of a mouse N2 mapping cross was leveraged against sleep-state phenotypic variation as well as quantitative gene expression measurement in key brain regions using integrative genomics approaches to uncover multiple causal sleep-state regulatory genes, including several surprising novel candidates, which interact as components of networks that modulate REM sleep and wake. In particular, it was discovered that a core network module, consisting of 20 genes, involved in the regulation of REM sleep duration is conserved across the cortex, hypothalamus, and thalamus. A novel application of a formal causal inference test was also used to identify those genes directly regulating sleep via control of expression. CONCLUSION Systems genetics approaches reveal novel candidate genes, complex networks and specific transcriptional regulators of REM sleep and wake duration in mammals.
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Cheng F, Li X, Li Y, Wang C, Wang T, Liu G, Baskys A, Uéda K, Chan P, Yu S. α-Synuclein promotes clathrin-mediated NMDA receptor endocytosis and attenuates NMDA-induced dopaminergic cell death. J Neurochem 2011; 119:815-25. [DOI: 10.1111/j.1471-4159.2011.07460.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thakur S, Du J, Hourani S, Ledent C, Li JM. Inactivation of adenosine A2A receptor attenuates basal and angiotensin II-induced ROS production by Nox2 in endothelial cells. J Biol Chem 2010; 285:40104-13. [PMID: 20940302 PMCID: PMC3000993 DOI: 10.1074/jbc.m110.184606] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelial cells (ECs) express a Nox2 enzyme, which, by generating reactive oxygen species (ROS), contributes to EC redox signaling and angiotensin II (AngII)-induced endothelial dysfunction. ECs also express abundantly an adenosine A(2A) receptor (A(2A)R), but its role in EC ROS production remains unknown. In this study, we investigated the role of A(2A)R in the regulation of Nox2 activity and signaling in ECs with or without acute AngII stimulation. In cultured ECs (SVEC4-10), AngII (100 nm, 30 min) significantly increased Nox2 membrane translocation and association with A(2A)R. These were accompanied by p47(phox), ERK1/2, p38 MAPK, and Akt phosphorylation and an increased ROS production (169 ± 0.04%). These AngII effects were inhibited back to the control levels by a specific A(2A)R antagonist (SCH58261), or adenosine deaminase, or by knockdown of A(2A)R or Nox2 using specific siRNAs. Knockdown of A(2A)R, as determined by Western blotting, decreased Nox2 and p47(phox) expression. In wild-type mouse aorta, SCH58261 significantly reduced acute AngII-induced ROS production and preserved endothelium-dependent vessel relaxation to acetylcholine. These results were further confirmed by using aortas from A(2A)R knock-out mice. In conclusion, A(2A)R is involved in the regulation of EC ROS production by Nox2. Inhibition or blockade of A(2A)R protects ECs from acute AngII-induced oxidative stress, MAPK activation, and endothelium dysfunction.
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Affiliation(s)
- Sapna Thakur
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
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Wong CO, Sukumar P, Beech DJ, Yao X. Nitric oxide lacks direct effect on TRPC5 channels but suppresses endogenous TRPC5-containing channels in endothelial cells. Pflugers Arch 2010; 460:121-30. [PMID: 20390293 PMCID: PMC3622007 DOI: 10.1007/s00424-010-0823-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/07/2010] [Accepted: 03/09/2010] [Indexed: 01/02/2023]
Abstract
TRPC5 is a member of the canonical transient receptor potential (TRPC) family of proteins that forms cationic channels either through homomultimeric assembly or heteromultimeric coordination with other TRPC proteins. It is expressed in a variety of cells including central neurones and endothelial cells and has susceptibility to stimulation by multiple factors. Here we investigated if TRPC5 is sensitive to nitric oxide. Mouse TRPC5 or human TRPC5 was over-expressed in HEK293 cells, and TRPC5 activity was determined by measuring the cytosolic Ca2+ concentration with an indicator dye or by recording membrane current under voltage clamp. TRPC5 activity could be evoked by carbachol acting at muscarinic receptors, lanthanum, or a reducing agent. However, S-nitroso-N-acetylpenicillamine (SNAP) and diethylamine NONOate (DEA-NONOate) failed to stimulate or inhibit TRPC5 at concentrations that generated nitric oxide, caused vasorelaxation, or suppressed activity of TRPC6 via protein kinase G. At high concentrations, SNAP (but not DEA-NONOate) occasionally stimulated TRPC5 but the effect was confounded by background TRPC5-independent Ca2+ signals. Endogenous Ca2+-entry in bovine aortic endothelial cells (BAECs) was suppressed by SNAP; TRPC5 blocking antibody or dominant-negative mutant TRPC5 suppressed this Ca2+ entry and occluded the effect of SNAP. The data suggest that nitric oxide is not a direct modulator of homomeric TRPC5 channels but may inhibit endogenous BAEC channels that contain TRPC5.
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Affiliation(s)
- Ching-On Wong
- />Li Ka Shing Insitute of Health Sciences and School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong People’s Republic of China
| | - Piruthivi Sukumar
- />Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - David J. Beech
- />Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - Xiaoqiang Yao
- />Li Ka Shing Insitute of Health Sciences and School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong People’s Republic of China
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Leung YK, Du J, Huang Y, Yao X. Cyclic nucleotide-gated channels contribute to thromboxane A2-induced contraction of rat small mesenteric arteries. PLoS One 2010; 5:e11098. [PMID: 20559420 PMCID: PMC2885410 DOI: 10.1371/journal.pone.0011098] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Accepted: 05/18/2010] [Indexed: 11/18/2022] Open
Abstract
Background Thromboxane A2 (TxA2)-induced smooth muscle contraction has been implicated in cardiovascular, renal and respiratory diseases. This contraction can be partly attributed to TxA2-induced Ca2+ influx, which resulted in vascular contraction via Ca2+-calmodulin-MLCK pathway. This study aims to identify the channels that mediate TxA2-induced Ca2+ influx in vascular smooth muscle cells. Methodology/Principal Findings Application of U-46619, a thromboxane A2 mimic, resulted in a constriction in endothelium-denuded small mesenteric artery segments. The constriction relies on the presence of extracellular Ca2+, because removal of extracellular Ca2+ abolished the constriction. This constriction was partially inhibited by an L-type Ca2+ channel inhibitor nifedipine (0.5–1 µM). The remaining component was inhibited by L-cis-diltiazem, a selective inhibitor for CNG channels, in a dose-dependent manner. Another CNG channel blocker LY83583 [6-(phenylamino)-5,8-quinolinedione] had similar effect. In the primary cultured smooth muscle cells derived from rat aorta, application of U46619 (100 nM) induced a rise in cytosolic Ca2+ ([Ca2+]i), which was inhibited by L-cis-diltiazem. Immunoblot experiments confirmed the presence of CNGA2 protein in vascular smooth muscle cells. Conclusions/Significance These data suggest a functional role of CNG channels in U-46619-induced Ca2+ influx and contraction of smooth muscle cells.
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Affiliation(s)
- Yuk Ki Leung
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Juan Du
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Physiology, Anhui Medical University, He Fei, China
| | - Yu Huang
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
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13
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Wong CO, Yao X. Cyclic nucleotide-gated channels: a familiar channel family with a new function? Future Cardiol 2010; 4:505-15. [PMID: 19804344 DOI: 10.2217/14796678.4.5.505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The cyclic nucleotide-gated (CNG) channel is a family of nonselective cation channels that open in response to an elevated cyclic nucleotide level. Cyclic nucleotides, particularly cAMP and cGMP, govern a great diversity of cellular functions. While the pivotal roles of CNG channels in the visual and olfactory systems have been well established in the past decade, relatively few studies were performed regarding the functional roles of CNG channels in non-neuronal systems. Cyclic nucleotides and Ca2+ are key signaling molecules in cardiovascular systems. Given that CNG channels are expressed in vascular tissues, several recent studies have explored the possible functional role of CNG channels in cardiovascular systems. This article intends to summarize some recent developments regarding the expression and functional role of CNG channels in the cardiovascular system.
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Affiliation(s)
- Ching-On Wong
- The Chinese University of Hong Kong, Department of Physiology & Li Ka Shing Insitute of Health Sciences, Faculty of Medicine, Hong Kong, China.
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14
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Wong CO, Huang Y, Yao X. Genistein potentiates activity of the cation channel TRPC5 independently of tyrosine kinases. Br J Pharmacol 2010; 159:1486-96. [PMID: 20233211 DOI: 10.1111/j.1476-5381.2010.00636.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE TRPC5 is a Ca(2+)-permeable channel with multiple modes of activation. We have explored the effects of genistein, a plant-derived isoflavone, on TRPC5 activity, and the mechanism(s) involved. EXPERIMENTAL APPROACH Effects of genistein on TRPC5 channels were investigated in TRPC5-over-expressing human embryonic kidney 293 (HEK) cells and bovine aortic endothelial cells (BAECs) using fluorescent Ca(2+) imaging and electrophysiological techniques. KEY RESULTS In TRPC5-over-expressing HEK cells, genistein stimulated TRPC5-mediated Ca(2+) influx, concentration dependently (EC(50)= 93 microM). Genistein and lanthanum activated TRPC5 channels synergistically. Effects of genistein on TRPC5 channels were mimicked by daidzein (100 microM), a genistein analogue inactive as a tyrosine kinase inhibitor, but not by known tyrosine kinase inhibitors herbimycin (2 microM), PP2 (20 microM) and lavendustin A (10 microM). Action of genistein on TRPC5 channels was not affected by an oestrogen receptor inhibitor ICI-182780 (50 microM) or a phospholipase C inhibitor U73122 (10 microM), suggesting genistein did not act through oestrogen receptors or phospholipase C. In BAECs, genistein (100 microM) stimulated TRPC5-mediated Ca(2+) influx. In patch clamp studies, both genistein (50 microM) and daidzein (50 microM) augmented TRPC5-mediated whole-cell cation current in TRPC5 over-expressing HEK cells. Genistein stimulated TRPC5 channel activity in excised inside-out membrane patch, suggesting that its action was relatively direct and did not require cytosolic factors. CONCLUSIONS AND IMPLICATIONS The present study is the first to demonstrate stimulation of a TRP channel by isoflavones. Genistein is a lipophilic compound able to stimulate TRPC5 activity in TRPC5-over-expressing HEK cells and in native vascular endothelial cells.
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Affiliation(s)
- Ching-On Wong
- Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
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15
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Store-operated calcium entry channels in pulmonary endothelium: the emerging story of TRPCS and Orai1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 661:137-54. [PMID: 20204728 DOI: 10.1007/978-1-60761-500-2_9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cells of diverse origin utilize shifts in cytosolic calcium concentrations as intracellular signals to elicit physiological responses. In endothelium, inflammatory first messengers increase cytosolic calcium as a signal to disrupt cell-cell borders and produce inter-cellular gaps. Calcium influx across the plasma membrane is required to initiate barrier disruption, although the calcium entry mechanism responsible for this effect remains poorly understood. This chapter highlights recent efforts to define the molecular anatomy of the ion channel responsible for triggering endothelial cell gap formation. Resolving the identity and function of this calcium channel will pave the way for new anti-inflammatory therapeutic targets.
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16
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Kwan HY, Huang Y, Yao XQ, Leung FP. Role of cyclic nucleotides in the control of cytosolic Ca2+ levels in vascular endothelial cells. Clin Exp Pharmacol Physiol 2009; 36:857-66. [PMID: 19413591 DOI: 10.1111/j.1440-1681.2009.05199.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
1. Endothelial cells have a key role in the cardiovascular system. Most endothelial cell functions depend on changes in cytosolic Ca(2+) concentrations ([Ca(2+)](i)) to some extent and Ca2+ signalling acts to link external stimuli with the synthesis and release of regulatory factors in endothelial cells. The [Ca(2+)](i) is maintained by a well-balanced Ca(2+) flux across the endoplasmic reticulum and plasma membrane. 2. Cyclic nucleotides, such as cAMP and cGMP, are very important second messengers. The cyclic nucleotides can affect [Ca(2+)](i) directly or indirectly (via the actions of protein kinase (PK) A or PKG-mediated phosphorylation) by regulating Ca(2+) mobilization and Ca(2+) influx. Fine-tuning of [Ca(2+)](i) is also fundamental to protect endothelial cells against damaged caused by the excessive accumulation of Ca(2+). 3. Therapeutic agents that control cAMP and cGMP levels have been used to treat various cardiovascular diseases. 4. The aim of the present review is to discuss: (i) the functions of endothelial cells; (ii) the importance of [Ca(2+)](i) in endothelial cells; (iii) the impact of excessive [Ca(2+)](i) in endothelial cells; and (iv) the balanced control of [Ca(2+)](i) in endothelial cells via involvement of cyclic nucleotides (cAMP and cGMP) and their general effectors.
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Affiliation(s)
- H Y Kwan
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
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17
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Kwan HY, Shen B, Ma X, Kwok YC, Huang Y, Man YB, Yu S, Yao X. TRPC1 Associates With BK
Ca
Channel to Form a Signal Complex in Vascular Smooth Muscle Cells. Circ Res 2009; 104:670-8. [DOI: 10.1161/circresaha.108.188748] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
TRPC1 (transient receptor potential canonical 1) is a Ca
2+
-permeable cation channel involved in diverse physiological function. TRPC1 may associate with other proteins to form a signaling complex, which is crucial for channel function. In the present study, we investigated the interaction between TRPC1 and large conductance Ca
2+
-sensitive K
+
channel (BK
Ca
). With the use of potentiometric fluorescence dye DiBAC
4
(3), we found that store-operated Ca
2+
influx resulted in membrane hyperpolarization of vascular smooth muscle cells (VSMCs). The hyperpolarization was inhibited by an anti-TRPC1 blocking antibody T1E3 and 2 BK
Ca
channel blockers, charybdotoxin and iberiotoxin. These data were confirmed by sharp microelectrode measurement of membrane potential in VSMCs of intact arteries. Furthermore, T1E3 treatment markedly enhanced the membrane depolarization and contraction of VSMCs in response to several contractile agonists including phenylephrine, endothelin-1, and U-46619. In coimmunoprecipitation experiments, an antibody against BK
Ca
α-subunit [BK
Ca
(α)] could pull down TRPC1, and moreover an anti-TRPC1 antibody could reciprocally pull down BK
Ca
(α). Double-labeling immunocytochemistry showed that TRPC1 and BK
Ca
were colocalized in the same subcellular regions, mainly on the plasma membrane, in VSMCs. These data suggest that, TRPC1 physically associates with BK
Ca
in VSMCs and that Ca
2+
influx through TRPC1 activates BK
Ca
to induce membrane hyperpolarization. The hyperpolarizing effect of TRPC1-BK
Ca
coupling could serve to reduce agonist-induced membrane depolarization, thereby preventing excessive contraction of VSMCs to contractile agonists.
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Affiliation(s)
- Hiu-Yee Kwan
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Bing Shen
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Xin Ma
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yuk-Chi Kwok
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yu Huang
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yu-Bun Man
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Shan Yu
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Xiaoqiang Yao
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
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18
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Shen B, Cheng KT, Leung YK, Kwok YC, Kwan HY, Wong CO, Chen ZY, Huang Y, Yao X. Epinephrine-induced Ca2+ influx in vascular endothelial cells is mediated by CNGA2 channels. J Mol Cell Cardiol 2008; 45:437-45. [PMID: 18621055 DOI: 10.1016/j.yjmcc.2008.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 05/27/2008] [Accepted: 06/13/2008] [Indexed: 10/21/2022]
Abstract
Epinephrine, through its action on beta-adrenoceptors, may induce endothelium-dependent vascular dilation, and this action is partly mediated by a cytosolic Ca(2+) ([Ca(2+)](i)) change in endothelial cells. In the present study, we explored the molecular identity of the channels that mediate epinephrine-induced endothelial Ca(2+) influx and subsequent vascular relaxation. Patch clamp recorded an epinephrine- and cAMP-activated cation current in the primary cultured bovine aortic endothelial cells (BAECs) and H5V endothelial cells. L-cis-diltiazem and LY-83583, two selective inhibitors for cyclic nucleotide-gated channels, diminished this cation current. Furthermore, this cation current was greatly reduced by a CNGA2-specific siRNA in H5V cells. With the use of fluorescent Ca(2+) dye, it was found that epinephrine and isoprenaline, a beta-adrenoceptor agonist, induced endothelial Ca(2+) influx in the presence of bradykinin. This Ca(2+) influx was inhibited by L-cis-diltiazem and LY-83583, and by a beta(2)-adrenoceptor antagonist ICI-118551. CNGA2-specific siRNA also diminished this Ca(2+) influx in H5V cells. Furthermore, L-cis-diltiazem and LY-83583 inhibited the endothelial Ca(2+) influx in isolated mouse aortic strips. L-cis-diltiazem also markedly reduced the endothelium-dependent vascular dilation to isoprenaline in isolated mouse aortic segments. In summary, CNG channels, CNGA2 in particular, mediate beta-adrenoceptor agonist-induced endothelial Ca(2+) influx and subsequent vascular dilation.
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Affiliation(s)
- Bing Shen
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
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