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Lim XR, Drumm BT, Sergeant GP, Hollywood MA, Thornbury KD. Ca 2+ -activated Cl - channels (TMEM16A) underlie spontaneous electrical activity in isolated mouse corpus cavernosum smooth muscle cells. Physiol Rep 2022; 10:e15504. [PMID: 36394209 PMCID: PMC9669617 DOI: 10.14814/phy2.15504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 11/18/2022] Open
Abstract
Penile detumescence is maintained by tonic contraction of corpus cavernosum smooth muscle cells (CCSMC), but the underlying mechanisms have not been fully elucidated. The purpose of this study was to characterize the mechanisms underlying activation of TMEM16A Ca2+ -activated Cl- channels in freshly isolated murine CCSMC. Male C57BL/6 mice aged 10-18 weeks were euthanized via intraperitoneal injection of sodium pentobarbital (100 mg.kg-1 ). Whole-cell patch clamp, pharmacological, and immunocytochemical experiments were performed on isolated CCSM. Tension measurements were performed in whole tissue. TMEM16A expression in murine corpus cavernosum was confirmed using immunocytochemistry. Isolated CCSMC developed spontaneous transient inward currents (STICs) under voltage clamp and spontaneous transient depolarizations (STDs) in current clamp mode of the whole cell, perforated patch clamp technique. STICs reversed close to the predicted Cl- equilibrium potential and both STICs and STDs were blocked by the TMEM16A channel blockers, Ani9 and CaCC(inh)-A01. These events were also blocked by GSK7975A (ORAI inhibitor), cyclopiazonic acid (CPA, sarcoplasmic reticulum [SR] Ca2+- ATPase blocker), tetracaine (RyR blocker), and 2APB (IP3 R blocker), suggesting that they were dependent on Ca2+ release from intracellular Ca2+ stores. Nifedipine (L-type Ca2+ channel blocker) did not affect STICs, but reduced the duration of STDs. Phenylephrine induced transient depolarizations and transient inward currents which were blocked by Ani9. Similarly, phenylephrine induced phasic contractions of intact corpus cavernosum muscle strips and these events were also inhibited by Ani9. This study suggests that contraction of CCSM is regulated by activation of TMEM16A channels and therefore inhibition of these channels could lead to penile erection.
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Affiliation(s)
- Xin Rui Lim
- Smooth Muscle Research CentreDundalk Institute of TechnologyDublinIreland
| | - Bernard T. Drumm
- Smooth Muscle Research CentreDundalk Institute of TechnologyDublinIreland
| | - Gerard P. Sergeant
- Smooth Muscle Research CentreDundalk Institute of TechnologyDublinIreland
| | - Mark A. Hollywood
- Smooth Muscle Research CentreDundalk Institute of TechnologyDublinIreland
| | - Keith D. Thornbury
- Smooth Muscle Research CentreDundalk Institute of TechnologyDublinIreland
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2
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Hashimoto D, Hirashima T, Yamamura H, Kataoka T, Fujimoto K, Hyuga T, Yoshiki A, Kimura K, Kuroki S, Tachibana M, Suzuki K, Yamamoto N, Morioka S, Sasaki T, Yamada G. Dynamic erectile responses of a novel penile organ model utilizing TPEM†. Biol Reprod 2021; 104:875-886. [PMID: 33511393 DOI: 10.1093/biolre/ioab011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two-photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (Cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction-related genes, Hypoxia-inducible factor 1-alpha (Hif1a), glutathione peroxidase 1 (Gpx1), Ras homolog family member A (RhoA), and Rho-associated protein kinase (Rock), was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.
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Affiliation(s)
- Daiki Hashimoto
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Tsuyoshi Hirashima
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Tomoya Kataoka
- Department of Clinical Pharmaceutics, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Kota Fujimoto
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Taiju Hyuga
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Atsushi Yoshiki
- Experimental Animal Division, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
| | - Kazunori Kimura
- Department of Clinical Pharmaceutics, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.,Department of Hospital Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Shunsuke Kuroki
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Makoto Tachibana
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Kentaro Suzuki
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Nobuhiko Yamamoto
- Cellular and Molecular Neurobiology Group, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Shin Morioka
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takehiko Sasaki
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Gen Yamada
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
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3
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Feng M, Wang Z, Liu Z, Liu D, Zheng K, Lu P, Liu C, Zhang M, Li J. The RyR–Cl
Ca
–VDCC axis contributes to spontaneous tone in urethral smooth muscle. J Cell Physiol 2019; 234:23256-23267. [PMID: 31161632 DOI: 10.1002/jcp.28892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Mei Feng
- Central Laboratory Shandong Provincial Hospital Affiliated to Shandong University Jinan China
- Department of Microbiology and Physiological Systems University of Massachusetts Medical School Worcester Massachusetts
- Central Laboratory Shandong Provincial Hospital Affiliated to Shandong First Medical University Jinan China
| | - Zhaoyang Wang
- Operating Room Jinan Central Hospital Affiliated to Shandong University Jinan China
| | - Zheng Liu
- Department of Urology Shandong Provincial Hospital Affiliated to Shandong University Jinan China
| | - Donghai Liu
- Department of Microbiology and Physiological Systems University of Massachusetts Medical School Worcester Massachusetts
| | - Kaizhi Zheng
- Department of Microbiology and Physiological Systems University of Massachusetts Medical School Worcester Massachusetts
| | - Ping Lu
- Department of Microbiology and Physiological Systems University of Massachusetts Medical School Worcester Massachusetts
| | - Chuanyong Liu
- Department of Physiology, School of Basic Medicine, Cheeloo College of Medicine Shandong University Jinan China
| | - Min Zhang
- Arts and Science Department University of Toronto Toronto Canada
| | - Jingxin Li
- Department of Physiology, School of Basic Medicine, Cheeloo College of Medicine Shandong University Jinan China
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4
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Thornbury KD, Hollywood MA, Sergeant GP. Ion Channels and Intracellular Calcium Signalling in Corpus Cavernosum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:171-194. [PMID: 31183827 DOI: 10.1007/978-981-13-5895-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The corpus cavernosum smooth muscle is important for both erection of the penis and for maintaining penile flaccidity. Most of the time, the smooth muscle cells are in a contracted state, which limits filling of the corpus sinuses with blood. Occasionally, however, they relax in a co-ordinated manner, allowing filling to occur. This results in an erection. When contractions of the corpus cavernosum are measured, it can be deduced that the muscle cells work together in a syncytium, for not only do they spontaneously contract in a co-ordinated manner, but they also synchronously relax. It is challenging to understand how they achieve this.In this review we will attempt to explain the activity of the corpus cavernosum, firstly by summarising current knowledge regarding the role of ion channels and how they influence tone, and secondly by presenting data on the intracellular Ca2+ signals that interact with the ion channels. We propose that spontaneous Ca2+ waves act as a primary event, driving transient depolarisation by activating Ca2+-activated Cl- channels. Depolarisation then facilitates Ca2+ influx via L-type voltage-dependent Ca2+ channels. We propose that the spontaneous Ca2+ oscillations depend on Ca2+ release from both ryanodine- and inositol trisphosphate (IP3)-sensitive stores and that modulation by signalling molecules is achieved mainly by interactions with the IP3-sensitive mechanism. This pacemaker mechanism is inhibited by nitric oxide (acting through cyclic GMP) and enhanced by noradrenaline. By understanding these mechanisms better, it might be possible to design new treatments for erectile dysfunction.
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Affiliation(s)
- Keith D Thornbury
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland.
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
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5
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Yip KP, Balasubramanian L, Kan C, Wang L, Liu R, Ribeiro-Silva L, Sham JSK. Intraluminal pressure triggers myogenic response via activation of calcium spark and calcium-activated chloride channel in rat renal afferent arteriole. Am J Physiol Renal Physiol 2018; 315:F1592-F1600. [PMID: 30089032 DOI: 10.1152/ajprenal.00239.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Myogenic contraction of renal arterioles is an important regulatory mechanism for renal blood flow autoregulation. We have previously demonstrated that integrin-mediated mechanical force increases the occurrence of Ca2+ sparks in freshly isolated renal vascular smooth muscle cells (VSMCs). To further test whether the generation of Ca2+ sparks is a downstream signal of mechanotransduction in pressure-induced myogenic constriction, the relationship between Ca2+ sparks and transmural perfusion pressure was investigated in intact VSMCs of pressurized rat afferent arterioles. Spontaneous Ca2+ sparks were found in VSMCs when afferent arterioles were perfused at 80 mmHg. The spark frequency was significantly increased when perfusion pressure was increased to 120 mmHg. A similar increase of spark frequency was also observed in arterioles stimulated with β1-integrin-activating antibody. Moreover, spark frequency was significantly higher in arterioles of spontaneous hypertensive rats at 80 and 120 mmHg. Spontaneous membrane current recorded using whole cell perforated patch in renal VSMCs showed predominant activity of spontaneous transient inward currents instead of spontaneous transient outward currents when holding potential was set close to physiological resting membrane potential. Real-time PCR and immunohistochemistry confirmed the expression of Ca2+-activated Cl- channel (ClCa) TMEM16A in renal VSMCs. Inhibition of TMEM16A with T16Ainh-A01 impaired the pressure-induced myogenic contraction in perfused afferent arterioles. Our study, for the first time to our knowledge, detected Ca2+ sparks in VSMCs of intact afferent arterioles, and their frequencies were positively modulated by the perfusion pressure. Our results suggest that Ca2+ sparks may couple to ClCa channels and trigger pressure-induced myogenic constriction via membrane depolarization.
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Affiliation(s)
- Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Lavanya Balasubramanian
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Chen Kan
- Department of Industrial, Manufacturing, and System Engineering, University of Texas at Arlington , Arlington, Texas
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Luisa Ribeiro-Silva
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - James S K Sham
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland
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6
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Rizaner N, Onkal R, Fraser SP, Pristerá A, Okuse K, Djamgoz MBA. Intracellular calcium oscillations in strongly metastatic human breast and prostate cancer cells: control by voltage-gated sodium channel activity. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:735-748. [PMID: 27665102 DOI: 10.1007/s00249-016-1170-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/27/2016] [Accepted: 08/30/2016] [Indexed: 12/21/2022]
Abstract
The possible association of intracellular Ca2+ with metastasis in human cancer cells is poorly understood. We have studied Ca2+ signaling in human prostate and breast cancer cell lines of strongly versus weakly metastatic potential in a comparative approach. Intracellular free Ca2+ was measured using a membrane-permeant fluorescent Ca2+-indicator dye (Fluo-4 AM) and confocal microscopy. Spontaneous Ca2+ oscillations were observed in a proportion of strongly metastatic human prostate and breast cancer cells (PC-3M and MDA-MB-231, respectively). In contrast, no such oscillations were observed in weakly/non metastatic LNCaP and MCF-7 cells, although a rise in the resting Ca2+ level could be induced by applying a high-K+ solution. Various parameters of the oscillations depended on extracellular Ca2+ and voltage-gated Na+ channel activity. Treatment with either tetrodotoxin (a general blocker of voltage-gated Na+ channels) or ranolazine (a blocker of the persistent component of the channel current) suppressed the Ca2+ oscillations. It is concluded that the functional voltage-gated Na+ channel expression in strongly metastatic cancer cells makes a significant contribution to generation of oscillatory intracellular Ca2+ activity. Possible mechanisms and consequences of the Ca2+ oscillations are discussed.
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Affiliation(s)
- Nahit Rizaner
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. .,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey.
| | - Rustem Onkal
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey
| | - Scott P Fraser
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Alessandro Pristerá
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Kenji Okuse
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Mustafa B A Djamgoz
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey
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7
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Leblanc N, Forrest AS, Ayon RJ, Wiwchar M, Angermann JE, Pritchard HAT, Singer CA, Valencik ML, Britton F, Greenwood IA. Molecular and functional significance of Ca(2+)-activated Cl(-) channels in pulmonary arterial smooth muscle. Pulm Circ 2015; 5:244-68. [PMID: 26064450 DOI: 10.1086/680189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/22/2014] [Indexed: 12/31/2022] Open
Abstract
Increased peripheral resistance of small distal pulmonary arteries is a hallmark signature of pulmonary hypertension (PH) and is believed to be the consequence of enhanced vasoconstriction to agonists, thickening of the arterial wall due to remodeling, and increased thrombosis. The elevation in arterial tone in PH is attributable, at least in part, to smooth muscle cells of PH patients being more depolarized and displaying higher intracellular Ca(2+) levels than cells from normal subjects. It is now clear that downregulation of voltage-dependent K(+) channels (e.g., Kv1.5) and increased expression and activity of voltage-dependent (Cav1.2) and voltage-independent (e.g., canonical and vanilloid transient receptor potential [TRPC and TRPV]) Ca(2+) channels play an important role in the functional remodeling of pulmonary arteries in PH. This review focuses on an anion-permeable channel that is now considered a novel excitatory mechanism in the systemic and pulmonary circulations. It is permeable to Cl(-) and is activated by a rise in intracellular Ca(2+) concentration (Ca(2+)-activated Cl(-) channel, or CaCC). The first section outlines the biophysical and pharmacological properties of the channel and ends with a description of the molecular candidate genes postulated to encode for CaCCs, with particular emphasis on the bestrophin and the newly discovered TMEM16 and anoctamin families of genes. The second section provides a review of the various sources of Ca(2+) activating CaCCs, which include stimulation by mobilization from intracellular Ca(2+) stores and Ca(2+) entry through voltage-dependent and voltage-independent Ca(2+) channels. The third and final section summarizes recent findings that suggest a potentially important role for CaCCs and the gene TMEM16A in PH.
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Affiliation(s)
- Normand Leblanc
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Abigail S Forrest
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Ramon J Ayon
- Department of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Michael Wiwchar
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Jeff E Angermann
- School of Community Health Sciences, University of Nevada, Reno, Nevada, USA
| | - Harry A T Pritchard
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
| | - Cherie A Singer
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Maria L Valencik
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Fiona Britton
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
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8
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Fry CH, Jabr RI. T-type Ca2+ channels and the urinary and male genital tracts. Pflugers Arch 2014; 466:781-9. [PMID: 24463704 DOI: 10.1007/s00424-014-1446-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 11/26/2022]
Abstract
T-type Ca(2+) channels are widely expressed throughout the urinary and male genital tracts, generally alongside L-type Ca(2+) channels. The use of pharmacological blockers of these channels has suggested functional roles in all regions, with the possible exception of the ureter. Their functional expression is apparent not just in smooth muscle cells but also in interstitial cells that lie in close proximity to muscle, nerve and epithelial components of these tissues. Thus, T-type Ca(2+) channels can contribute directly to modulation of muscle function and indirectly to changes of epithelial and nerve function. T-type Ca(2+) channel activity modulates phasic contractile activity, especially in conjunction with Ca(2+)-activated K(+) channels, and also to agonist-dependent responses in different tissues. Upregulation of channel density occurs in pathological conditions associated with enhanced contractile responses, e.g. overactive bladder, but it is unclear if this is causal or a response to the pathological state. Moreover, T-type Ca(2+) channels may have a role in the development of prostate tumours regulating the secretion of mitogens from neuroendocrine cells. Although a number of selective channel blockers exist, their relative selectivity over L-type Ca(2+) channels is often low and makes evaluation of T-type Ca(2+) channel function in the whole organism difficult.
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Affiliation(s)
- C H Fry
- Department of Biochemistry and Physiology, University of Surrey, Guildford, GU2 7XH, UK,
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9
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Subedi KP, Paudel O, Sham JSK. Detection of differentially regulated subsarcolemmal calcium signals activated by vasoactive agonists in rat pulmonary artery smooth muscle cells. Am J Physiol Cell Physiol 2013; 306:C659-69. [PMID: 24352334 DOI: 10.1152/ajpcell.00341.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intracellular calcium (Ca(2+)) plays pivotal roles in distinct cellular functions through global and local signaling in various subcellular compartments, and subcellular Ca(2+) signal is the key factor for independent regulation of different cellular functions. In vascular smooth muscle cells, subsarcolemmal Ca(2+) is an important regulator of excitation-contraction coupling, and nucleoplasmic Ca(2+) is crucial for excitation-transcription coupling. However, information on Ca(2+) signals in these subcellular compartments is limited. To study the regulation of the subcellular Ca(2+) signals, genetically encoded Ca(2+) indicators (cameleon), D3cpv, targeting the plasma membrane (PM), cytoplasm, and nucleoplasm were transfected into rat pulmonary arterial smooth muscle cells (PASMCs) and Ca(2+) signals were monitored using laser scanning confocal microscopy. In situ calibration showed that the Kd for Ca(2+) of D3cpv was comparable in the cytoplasm and nucleoplasm, but it was slightly higher in the PM. Stimulation of digitonin-permeabilized cells with 1,4,5-trisphosphate (IP3) elicited a transient elevation of Ca(2+) concentration with similar amplitude and kinetics in the nucleoplasm and cytoplasm. Activation of G protein-coupled receptors by endothelin-1 and angiotensin II preferentially elevated the subsarcolemmal Ca(2+) signal with higher amplitude in the PM region than the nucleoplasm and cytoplasm. In contrast, the receptor tyrosine kinase activator, platelet-derived growth factor, elicited Ca(2+) signals with similar amplitudes in all three regions, except that the rise-time and decay-time were slightly slower in the PM region. These data clearly revealed compartmentalization of Ca(2+) signals in the subsarcolemmal regions and provide the basis for further investigations of differential regulation of subcellular Ca(2+) signals in PASMCs.
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Affiliation(s)
- Krishna P Subedi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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10
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Doyle C, Sergeant GP, Hollywood MA, McHale NG, Thornbury KD. Effects of Phenylephrine on Spontaneous Activity and L‐Type Ca2+ Current in Isolated Corpus Cavernosum Myocytes. J Sex Med 2012; 9:2795-805. [DOI: 10.1111/j.1743-6109.2012.02847.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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The promise of inhibition of smooth muscle tone as a treatment for erectile dysfunction: where are we now? Int J Impot Res 2011; 24:49-60. [PMID: 21975566 DOI: 10.1038/ijir.2011.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ten years ago, the inhibition of Rho kinase by intracavernosal injection of Y-27632 was found to induce an erectile response. This effect did not require activation of nitric oxide-mediated signaling, introducing a novel target pathway for the treatment of erectile dysfunction (ED), with potential added benefit in cases where nitric oxide bioavailability is attenuated (and thus phosphodiesterase type 5 (PDE5) inhibitors are less efficacious). Rho-kinase antagonists are currently being developed and tested for a wide range of potential uses. The inhibition of this calcium-sensitizing pathway results in blood vessel relaxation. It is also possible that blockade of additional smooth muscle contractile signaling mechanisms may have the same effect. In this review, we conducted an extensive search of pertinent literature using PUBMED. We have outlined the various pathways involved in the maintenance of penile smooth muscle tone and discussed the current potential benefit for the pharmacological inhibition of these targets for the treatment of ED.
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12
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Andersson KE. Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction. Pharmacol Rev 2011; 63:811-59. [PMID: 21880989 DOI: 10.1124/pr.111.004515] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.
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Affiliation(s)
- K-E Andersson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
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13
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Simpkins AN, Rudic RD, Roy S, Tsai HJ, Hammock BD, Imig JD. Soluble epoxide hydrolase inhibition modulates vascular remodeling. Am J Physiol Heart Circ Physiol 2010; 298:H795-806. [PMID: 20035028 PMCID: PMC2838550 DOI: 10.1152/ajpheart.00543.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 12/19/2010] [Indexed: 11/22/2022]
Abstract
The soluble epoxide hydrolase enzyme (SEH) and vascular remodeling are associated with cardiovascular disease. Although inhibition of SEH prevents smooth muscle cell proliferation in vitro, the effects of SEH inhibition on vascular remodeling in vivo and mechanisms of these effects remain unclear. Herein we determined the effects of SEH antagonism in an endothelium intact model of vascular remodeling induced by flow reduction and an endothelium denuded model of vascular injury. We demonstrated that chronic treatment of spontaneously hypertensive stroke-prone rats with 12-(3-adamantan-1-yl-ureido) dodecanoic acid, an inhibitor of SEH, improved the increment of inward remodeling induced by common carotid ligation to a level that was comparable with normotensive Wistar Kyoto rats. Similarly, mice with deletion of the gene responsible for the production of the SEH enzyme (Ephx2(-/-)) demonstrated enhanced inward vascular remodeling induced by carotid ligation. However, the hyperplastic response induced by vascular injury that denudes the endothelium was unabated by SEH inhibition or Ephx2 gene deletion. These results suggest that SEH inhibition or Ephx2 gene deletion antagonizes neointimal formation in vivo by mechanisms that are endothelium dependent. Thus SEH inhibition may have therapeutic potential for flow-induced remodeling and neointimal formation.
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Affiliation(s)
| | | | - S. Roy
- Department of Vascular Biology Center and
| | - H. J. Tsai
- Department of Entomology and University of California Davis Cancer Research Center, University of California, Davis, California
| | - B. D. Hammock
- Department of Entomology and University of California Davis Cancer Research Center, University of California, Davis, California
| | - J. D. Imig
- Department of Vascular Biology Center and
- Physiology, Medical College of Georgia, Augusta, Georgia
- Pharmacology and Toxicology and Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin; and
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14
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McCloskey C, Cagney V, Large R, Hollywood M, Sergeant G, McHale N, Thornbury K. Voltage‐dependent Ca2+ Currents Contribute to Spontaneous Ca2+ Waves in Rabbit Corpus Cavernosum Myocytes. J Sex Med 2009; 6:3019-31. [DOI: 10.1111/j.1743-6109.2009.01451.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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15
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Liu HG, Zhu GY, Wang YH. Expression and function of ryanodine receptors in rabbit penile corpus cavernosum smooth muscle cells. Andrologia 2009; 41:137-40. [DOI: 10.1111/j.1439-0272.2008.00904.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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16
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Xu L, Ting-Lou, Lv N, Zhu X, Chen Y, Yang J. Emodin augments calcium activated chloride channel in colonic smooth muscle cells by Gi/Go protein. Eur J Pharmacol 2009; 615:171-6. [PMID: 19409890 DOI: 10.1016/j.ejphar.2009.04.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 04/12/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022]
Abstract
Emodin is a natural anthraquinone in rhubarb. It has been identified as a prokinetic drug for gastrointestinal motility in Chinese traditional medicine. Emodin contracts smooth muscle by increasing the concentration of intracellular Ca(2+). In many smooth muscles, increasing intracellular Ca(2+) activates Ca(2+)-activated Cl(-) channels (ClCA). The study was aimed to investigate the effects of emodin on ClCA channels in colonic smooth muscle. 4 channel physiology signal acquire system was used to measure isometric contraction of smooth muscle strips. ClCA currents were recorded by EPC10 with perforated whole cell model. Emodin contracted strips and cells in colonic smooth muscle and augmented ClCA currents. Niflumic acid (NFA) and 4', 4'-diisothiostilbene-2, 2-disulfonic acid (DIDS) blocked the effects. Gi/Go protein inhibits protein kinase A (PKA) and protein kinase C (PKC), and PKA and PKC reduced ClCA currents. Pertussis toxin (PTX, a special inhibitor of Gi/Go protein), 8-bromoadenosine 38, 58-cyclic monophosphate (8-BrcAMP, a membrane-permeant protein kinase A activator) and Phorbol-12-myristate-13-acetate (PMA, a membrane-permeant protein kinase C activator) inhibited the effects on ClCA currents significantly. Our findings suggest that emodin augments ClCA channels to contract smooth muscle in colon, and the effect is induced mostly by enhancement of membrane Gi/Go protein signal transducer pathway.
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Affiliation(s)
- Long Xu
- Department of gastroenterology, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
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17
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Kuo YC, Chung SD, Liu SP, Chang HC, Yu HJ, Hsieh JT. The Role of Chloride Channels in Rat Corpus Cavernosum: In Vivo Study. J Sex Med 2009; 6:708-16. [DOI: 10.1111/j.1743-6109.2008.01062.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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18
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Sergeant GP, Craven M, Hollywood MA, McHale NG, Thornbury KD. Spontaneous Ca2+ waves in rabbit corpus cavernosum: modulation by nitric oxide and cGMP. J Sex Med 2008; 6:958-966. [PMID: 19138373 DOI: 10.1111/j.1743-6109.2008.01090.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Detumescent tone and subsequent relaxation by nitric oxide (NO) are essential processes that determine the erectile state of the penis. Despite this, the mechanisms involved are incompletely understood. It is often assumed that the tone is associated with a sustained high cytosolic Ca(2+) level in the corpus cavernosum smooth muscle cells, however, an alternative possibility is that oscillatory Ca(2+) signals regulate tone, and erection occurs as a result of inhibition of Ca(2+) oscillations by NO. AIMS The aim of this study is to determine if smooth muscle cells displayed spontaneous Ca(2+) oscillations and, if so, whether these were regulated by NO. METHODS Male New Zealand white rabbits were euthanized and smooth muscle cells were isolated by enzymatic dispersal for confocal imaging of intracellular Ca(2+) (using fluo-4AM) and patch clamp recording of spontaneous membrane currents. Thin tissue slices were also loaded with fluo-4AM for live imaging of Ca(2+). MAIN OUTCOME MEASURE Cytosolic Ca(2+) was measured in isolated smooth muscle cells and tissue slices. Results. Isolated rabbit corpus cavernosum smooth muscle cells developed spontaneous Ca(2+) waves that spread at a mean velocity of 65 microm/s. Dual voltage clamp/confocal recordings revealed that each of the Ca(2+) waves was associated with an inward current typical of the Ca(2+)-activated Cl(-) currents developed by these cells. The waves depended on an intact sarcoplasmic reticulum Ca(2+) store, as they were blocked by cyclopiazonic acid (Calbiochem, San Diego, CA, USA) and agents that interfere with ryanodine receptors and IP(3)-mediated Ca(2+) release. The waves were also inhibited by an NO donor (diethylamine NO; Tocris Bioscience, Bristol, Avon, UK), 3-(5-hydroxymethyl-2-furyl)-1-benzyl indazole (YC-1) (Alexis Biochemicals, Bingham, Notts, UK), 8-bromo-cyclic guanosine mono-phosphate (Tocris), and sildenafil (Viagra, Pfizer, Sandwich, Kent, UK). Regular Ca(2+) oscillations were also observed in whole tissue slices where they were clearly seen to precede contraction. This activity was also markedly inhibited by sildenafil, suggesting that it was under NO regulation. CONCLUSIONS These results provide a new basis for understanding detumescent tone in the corpus cavernosum and its inhibition by NO.
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Affiliation(s)
- Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Michael Craven
- Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Noel G McHale
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland;.
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19
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Bao R, Lifshitz LM, Tuft RA, Bellvé K, Fogarty KE, ZhuGe R. A close association of RyRs with highly dense clusters of Ca2+-activated Cl- channels underlies the activation of STICs by Ca2+ sparks in mouse airway smooth muscle. ACTA ACUST UNITED AC 2008; 132:145-60. [PMID: 18591421 PMCID: PMC2442178 DOI: 10.1085/jgp.200709933] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ca2+ sparks are highly localized, transient releases of Ca2+ from sarcoplasmic reticulum through ryanodine receptors (RyRs). In smooth muscle, Ca2+ sparks trigger spontaneous transient outward currents (STOCs) by opening nearby clusters of large-conductance Ca2+-activated K+ channels, and also gate Ca2+-activated Cl− (Cl(Ca)) channels to induce spontaneous transient inward currents (STICs). While the molecular mechanisms underlying the activation of STOCs by Ca2+ sparks is well understood, little information is available on how Ca2+ sparks activate STICs. In the present study, we investigated the spatial organization of RyRs and Cl(Ca) channels in spark sites in airway myocytes from mouse. Ca2+ sparks and STICs were simultaneously recorded, respectively, with high-speed, widefield digital microscopy and whole-cell patch-clamp. An image-based approach was applied to measure the Ca2+ current underlying a Ca2+ spark (ICa(spark)), with an appropriate correction for endogenous fixed Ca2+ buffer, which was characterized by flash photolysis of NPEGTA. We found that ICa(spark) rises to a peak in 9 ms and decays with a single exponential with a time constant of 12 ms, suggesting that Ca2+ sparks result from the nonsimultaneous opening and closure of multiple RyRs. The onset of the STIC lags the onset of the ICa(spark) by less than 3 ms, and its rising phase matches the duration of the ICa(spark). We further determined that Cl(Ca) channels on average are exposed to a [Ca2+] of 2.4 μM or greater during Ca2+ sparks. The area of the plasma membrane reaching this level is <600 nm in radius, as revealed by the spatiotemporal profile of [Ca2+] produced by a reaction-diffusion simulation with measured ICa(spark). Finally we estimated that the number of Cl(Ca) channels localized in Ca2+ spark sites could account for all the Cl(Ca) channels in the entire cell. Taken together these results lead us to propose a model in which RyRs and Cl(Ca) channels in Ca2+ spark sites localize near to each other, and, moreover, Cl(Ca) channels concentrate in an area with a radius of ∼600 nm, where their density reaches as high as 300 channels/μm2. This model reveals that Cl(Ca) channels are tightly controlled by Ca2+ sparks via local Ca2+ signaling.
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Affiliation(s)
- Rongfeng Bao
- Biomedical Imaging Group and Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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20
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Huang K, Ueda E, Chen Y, Walker AM. Paradigm-shifters: phosphorylated prolactin and short prolactin receptors. J Mammary Gland Biol Neoplasia 2008; 13:69-79. [PMID: 18219563 DOI: 10.1007/s10911-008-9072-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 01/04/2008] [Indexed: 11/28/2022] Open
Abstract
Since the discovery of physiologically-regulated prolactin (PRL) phosphorylation, one focus of the laboratory has been an examination of the different functions of the unmodified and phosphorylated hormone. In the mammary gland, unmodified PRL promotes growth activities, whereas phosphorylated or pseudophosphorylated PRL antagonizes this while also being a superior agonist for changes that favor differentiation. Phosphorylated PRL also increases expression of the short forms of the PRL receptor. These short forms of the receptor have functions beyond the accepted dominant negative and in mammary epithelial cells are capable of generating an intracellular signal leading to increased tight junction formation and beta-casein expression.
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Affiliation(s)
- KuangTzu Huang
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
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