51
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Reinach PS, Mergler S, Okada Y, Saika S. Ocular transient receptor potential channel function in health and disease. BMC Ophthalmol 2015; 15 Suppl 1:153. [PMID: 26818117 PMCID: PMC4895786 DOI: 10.1186/s12886-015-0135-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transient receptor potential (TRP) channels sense and transduce environmental stimuli into Ca(2+) transients that in turn induce responses essential for cell function and adaptation. These non-selective channels with variable Ca(2+) selectivity are grouped into seven different subfamilies containing 28 subtypes based on differences in amino acid sequence homology. Many of these subtypes are expressed in the eye on both neuronal and non-neuronal cells where they affect a host of stress-induced regulatory responses essential for normal vision maintenance. This article reviews our current knowledge about the expression, function and regulation of TRPs in different eye tissues. We also describe how under certain conditions TRP activation can induce responses that are maladaptive to ocular function. Furthermore, the possibility of an association between TRP mutations and disease is considered. These findings contribute to evidence suggesting that drug targeting TRP channels may be of therapeutic benefit in a clinical setting. We point out issues that must be more extensively addressed before it will be possible to decide with certainty that this is a realistic endeavor. Another possible upshot of future studies is that disease process progression can be better evaluated by profiling changes in tissue specific functional TRP subtype activity as well as their gene and protein expression.
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Affiliation(s)
- Peter S Reinach
- Department of Ophthalmology and Optometry, Wenzhou Medical University, 270 Xuejuan Road, Wenzhou, Zhejiang, 325027, P. R. China.
| | - Stefan Mergler
- Department of Ophthalmology, Charité-University Medicine Berlin, Campus Virchow-Clinic, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Yuka Okada
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
| | - Shizuya Saika
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
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Schäfer S, Ferioli S, Hofmann T, Zierler S, Gudermann T, Chubanov V. Mibefradil represents a new class of benzimidazole TRPM7 channel agonists. Pflugers Arch 2015; 468:623-34. [PMID: 26669310 DOI: 10.1007/s00424-015-1772-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 01/16/2023]
Abstract
Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) is a bi-functional protein comprising an ion channel moiety covalently linked to a protein kinase domain. Currently, the prevailing view is that a decrease in the cytosolic Mg(2+) concentration leads to activation of divalent cation-selective TRPM7 currents. TRPM7 plays a role in immune responses, hypotension, tissue fibrosis, and tumor progression and, therefore, represents a new promising therapeutic target. Because of the dearth of pharmacological tools, our mechanistic understanding of the role of TRPM7 in physiology and pathophysiology still lags behind. Therefore, we have recently carried out a high throughput screen for small-molecule activators of TRPM7. We have characterized the phenanthrene naltriben as a first stimulatory agonist of the TRPM7 channel. Surprisingly, the effect of naltriben on TRPM7 was found to be unaffected by the physiological levels of cytosolic Mg(2+). Here, we demonstrate that mibefradil and NNC 50-0396, two benzimidazole relatives of the TRPM7 inhibitor NS8593, are positive modulators of TRPM7. Using Ca(2+) imaging and the patch-clamp technique, we show that mibefradil activates TRPM7-mediated Ca(2+) entry and whole-cell currents. The response to mibefradil was fast, reversible, and reproducible. In contrast to naltriben, mibefradil efficiently activates TRPM7 currents only at physiological intracellular Mg(2+) concentrations, and its stimulatory effect was fully abrogated by high internal Mg(2+) levels. Consequently, a TRPM7 variant harboring a gain-of-function mutation was insensitive to further mibefradil activation. Finally, we observed that the effect of mibefradil was selective for TRPM7 when various TRP channels were tested. Taken together, mibefradil acts as a Mg(2+)-regulated agonist of the TRPM7 channel and, hence, uncovers a new class of TRPM7 agonists.
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Affiliation(s)
- Sebastian Schäfer
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Silvia Ferioli
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Thomas Hofmann
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Susanna Zierler
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, Munich, Germany
| | - Vladimir Chubanov
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany.
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Shindo Y, Yamanaka R, Suzuki K, Hotta K, Oka K. Intracellular magnesium level determines cell viability in the MPP(+) model of Parkinson's disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3182-91. [PMID: 26319097 DOI: 10.1016/j.bbamcr.2015.08.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/24/2015] [Accepted: 08/22/2015] [Indexed: 12/14/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder resulting from mitochondrial dysfunction in dopaminergic neurons. Mitochondria are believed to be responsible for cellular Mg²⁺ homeostasis. Mg²⁺ is indispensable for maintaining ordinal cellular functions, hence perturbation of the cellular Mg²⁺ homeostasis may be responsible for the disorders of physiological functions and diseases including PD. However, the changes in intracellular Mg²⁺ concentration ([Mg²⁺]i) and the role of Mg²⁺ in PD have still been obscure. In this study, we investigated [Mg²⁺]i and its effect on neurodegeneration in the 1-methyl-4-phenylpyridinium (MPP⁺) model of PD in differentiated PC12 cells. Application of MPP⁺ induced an increase in [Mg²⁺]i immediately via two different pathways: Mg²⁺ release from mitochondria and Mg²⁺ influx across cell membrane, and the increased [Mg²⁺]i sustained for more than 16 h after MPP⁺ application. Suppression of Mg²⁺ influx decreased the viability of the cells exposed to MPP⁺. The cell viability correlated highly with [Mg²⁺]i. In the PC12 cells with suppressed Mg²⁺ influx, ATP concentration decreased and the amount of reactive oxygen species (ROS) increased after an 8h exposure to MPP⁺. Our results indicate that the increase in [Mg²⁺]i inhibited cellular ROS generation and maintained ATP production, which resulted in the protection from MPP⁺ toxicity.
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Affiliation(s)
- Yutaka Shindo
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Ryu Yamanaka
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Koji Suzuki
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Kohji Hotta
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Kotaro Oka
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
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Abstract
Calcium (Ca2+) and magnesium (Mg2+) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca2+ and Mg2+ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca2+ and Mg2+; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.
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Affiliation(s)
- Yuyang Sun
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Pramod Sukumaran
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Anne Schaar
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Brij B Singh
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
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Mori Y, Takahashi N, Polat OK, Kurokawa T, Takeda N, Inoue M. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation. Pflugers Arch 2015; 468:85-97. [PMID: 26149285 PMCID: PMC4700073 DOI: 10.1007/s00424-015-1716-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of “O2 remodeling.” The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2.
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Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
- Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Onur Kerem Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Tatsuki Kurokawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masahiro Inoue
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
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Oh HG, Chun YS, Park CS, Kim TW, Park MK, Chung S. Regulation of basal autophagy by transient receptor potential melastatin 7 (TRPM7) channel. Biochem Biophys Res Commun 2015; 463:7-12. [DOI: 10.1016/j.bbrc.2015.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
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Lee HJ, Kim MC, Lim B, Kim BJ. Buxus Microphylla var. Koreana Nakai Extract for the Treatment of Gastric Cancer. J Pharmacopuncture 2015; 16:39-45. [PMID: 25780674 PMCID: PMC4331968 DOI: 10.3831/kpi.2013.16.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 06/12/2013] [Indexed: 11/24/2022] Open
Abstract
Objectives: Buxus Microphylla var. Koreana Nakai Extract (BMKNE) is used as a folk remedy for malaria and veneral disease. In the present study, we investigated the effects of BMKNE in the growth and the survival of AGS cells, the most common human gastric adenocarcinoma cell lines. Methods: The AGS cells were treated with varying concentrations of BMKNE. Analyses of the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Also, to identify the role of transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels. Results: Experimental results showed that the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were increased. Therefore, BMKNE was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 mitogen-activated protein kinase (MAPK) inhibitor), and by a c-jun NH2-terminal kinase (JNK) II inhibitor. Furthermore, BMKNE inhibited TRPM7 currents and TRPM7 channel over-expressions in HEK 293 cells, exacerbating BMKNE-induced cell death. Conclusions: These findings indicate that BMKNE inhibits the growth and the survival of gastric cancer cells due to a blockade of the TRPM7 channel’s activity and MAPK signaling. Therefore, BMKNE is a potential drug for treatment of gastric cancer, and both the TRPM7 channel and MAPK signaling may play an important role in survival in gastric cancer cells.
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Affiliation(s)
- Hee Jung Lee
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Min Chul Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Bora Lim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
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58
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Lim B, Lee HJ, Kim MC, Kim BJ. Effects of Ulmi Pumilae Cortex on AGS Gastric Cancer Cells. J Pharmacopuncture 2015; 16:55-61. [PMID: 25780669 PMCID: PMC4331962 DOI: 10.3831/kpi.2013.16.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/19/2013] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE Ulmi Pumilae Cortex(UPC) is a deciduous tree with uneven pinnate leaves and is classified as a subfamily of Ulmuceae and contains many pharmacologically active constituents. The aim of this study was to investigate the effects of UPC on the growth and survival of AGS cells, the most common human gastric adenocarcinoma cell lines. METHODS The AGS cells were treated with varying concentrations of UPC. Analyses of the sub G1, caspase-3 activity, and mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Furthermore, to identify the role of the transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels. RESULTS The addition of UPC to a culture medium inhibited AGS cell growth and survival. Experimental results showed that the sub G1, caspase-3 activity, and mitochondrial depolarization were increased. Furthermore, TRPM7 channel overexpression in HEK 293 cells exacerbated UPC-induced cell death. CONCLUSION These findings indicate that UPC inhibits the growth and survival of gastric cancer cells due to a blockade of the TRPM7 channel activity. Therefore, UPC is a potential drug for treatment of gastric cancer, and TRPM7 channels may play an important role in survival in cases of gastric cancer.
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Affiliation(s)
- Bora Lim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Hee Jung Lee
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Min Chul Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
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Reinach PS, Chen W, Mergler S. Polymodal roles of transient receptor potential channels in the control of ocular function. EYE AND VISION 2015; 2:5. [PMID: 26605361 PMCID: PMC4655450 DOI: 10.1186/s40662-015-0016-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/15/2015] [Indexed: 12/05/2022]
Abstract
Maintenance of intracellular Ca2+ levels at orders of magnitude below those in the extracellular environment is a requisite for preserving cell viability. Membrane channels contribute to such control through modulating their time-dependent opening and closing behaviour. Such regulation requires Ca2+ to serve as a second messenger mediating receptor control of numerous life-sustaining responses. Transient receptor potential (TRP) channels signal transduce a wide variety of different sensory stimuli to induce responses modulating cellular function. These channels are non-selective cation channels with variable Ca2+ selectivity having extensive sequence homology. They constitute a superfamily made up of 28 different members that are subdivided into 7 different subfamilies based on differences in sequence homology. Some of these TRP channel isotypes are expressed in the eye and localized to both neuronal and non-neuronal cell membranes. Their activation generates intracellular Ca2+ transients and other downstream-linked signalling events that affect numerous responses required for visual function. As there is an association between changes in functional TRP expression in various ocular diseases, there are efforts underway to determine if these channels can be used as drug targets to reverse declines in ocular function. We review here our current knowledge about the expression, function and regulation of TRPs in different eye tissues in health and disease. Furthermore, some of the remaining hurdles are described to developing safe and efficacious TRP channel modulators for use in a clinical setting.
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Affiliation(s)
- Peter S Reinach
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325027 P.R. China
| | - Weiwei Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325027 P.R. China
| | - Stefan Mergler
- Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, Klinik für Augenheilkunde, Augustenburger Platz 1, D-13353 Berlin, Germany
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60
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Turlova E, Bae CYJ, Deurloo M, Chen W, Barszczyk A, Horgen FD, Fleig A, Feng ZP, Sun HS. TRPM7 Regulates Axonal Outgrowth and Maturation of Primary Hippocampal Neurons. Mol Neurobiol 2014; 53:595-610. [PMID: 25502295 DOI: 10.1007/s12035-014-9032-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/30/2014] [Indexed: 11/25/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a calcium-permeable divalent cation channel and mediates neuronal cell death under ischemic stresses. In this study, we investigated the contribution of TRPM7 to neuronal development in mouse primary hippocampal neurons. We demonstrated that TRPM7 channels are highly expressed in the tips of the growth cone. Either knockdown of TRPM7 with target-specific shRNA or blocking channel conductance by a specific blocker waixenicin A enhanced axonal outgrowth in culture. Blocking TRPM7 activity by waixenicin A reduced calcium influx and accelerated the polarization of the hippocampal neurons as characterized by the development of distinct axons and dendrites. Furthermore, TRPM7 coprecipitated and colocalized with F-actin and α-actinin-1 at the growth cone. We conclude that calcium influx through TRPM7 inhibits axonal outgrowth and maturation by regulating the F-actin and α-actinin-1 protein complex. Inhibition of TRPM7 channel promotes axonal outgrowth, suggesting its therapeutic potential in neurodegenerative disorders.
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Affiliation(s)
- Ekaterina Turlova
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Christine Y J Bae
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Marielle Deurloo
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Wenliang Chen
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Andrew Barszczyk
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - F David Horgen
- College of Natural and Computational Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen's Medical Center, Honolulu, HI, 96720, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, Honolulu, HI, 96720, USA
| | - Zhong-Ping Feng
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Hong-Shuo Sun
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Pharmacology & Toxicology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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Leng TD, Li MH, Shen JF, Liu ML, Li XB, Sun HW, Branigan D, Zeng Z, Si HF, Li J, Chen J, Xiong ZG. Suppression of TRPM7 inhibits proliferation, migration, and invasion of malignant human glioma cells. CNS Neurosci Ther 2014; 21:252-61. [PMID: 25438992 DOI: 10.1111/cns.12354] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/15/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor with a dismal prognosis. Despite intensive study on tumor biology, the underlying mechanisms of the unlimited proliferation and progressive local invasion are still poorly understood, and no effective treatment has been developed for GBM patients. AIMS We determine the role of TRPM7 channels in the growth, migration, and infiltration of malignant glioma cells. METHODS Using a combination of RT-PCR, Western blot, and patch-clamp techniques, we demonstrated the expression of functional TRPM7 channels of A172 cells, a human glioma cell line, as well as in human glioma tissues. Furthermore, we evaluated the role of TRPM7 in growth, migration, and infiltration of A172 cells with MTT and transwell migration and invasion assays. RESULTS We showed the expression of functional TRPM7 channels in both A172 cells and human glioma tissues. Suppression of TRPM7 expression with TRPM7-siRNA dramatically reduced the proliferation, migration, and invasion of A172 cells. Pharmacological inhibition of TRPM7 channel with 2-aminoethoxydiphenyl borate (2-APB) showed a similar effect as TRPM7-siRNA. CONCLUSION We demonstrate that human glioma cells express functional TRPM7 channel and that activation of this channel plays an important role in the proliferation, migration, and invasion of malignant glioma cells. TRPM7 channel may represent a novel and promising target for therapeutic intervention of malignant glioma.
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Affiliation(s)
- Tian-Dong Leng
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, USA
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Natural and Synthetic Modulators of the TRPM7 Channel. Cells 2014; 3:1089-101. [PMID: 25437439 PMCID: PMC4276914 DOI: 10.3390/cells3041089] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 11/16/2022] Open
Abstract
Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bi-functional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in magnesium metabolism, cell motility, proliferation and differentiation. TRPM7 is associated with anoxic neuronal death, cardiac fibrosis and tumor progression highlighting TRPM7 as a new drug target. Recently, several laboratories have independently identified pharmacological compounds inhibiting or activating the TRPM7 channel. The recently found TRPM7 modulators were used as new experimental tools to unravel cellular functions of the TRPM7 channel. Here, we provide a concise overview of this emerging field.
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Visser D, Middelbeek J, van Leeuwen FN, Jalink K. Function and regulation of the channel-kinase TRPM7 in health and disease. Eur J Cell Biol 2014; 93:455-65. [DOI: 10.1016/j.ejcb.2014.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/24/2014] [Accepted: 07/01/2014] [Indexed: 11/30/2022] Open
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64
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Hwang MW, Kim BJ. Apoptotic Effects and Involvement of TRPM7 Channels of the Traditional Herbal Medicine, Dangkwisoo-San in Gastric Cancer Cells. INT J PHARMACOL 2014. [DOI: 10.3923/ijp.2014.398.405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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TRPM7 channels regulate glioma stem cell through STAT3 and Notch signaling pathways. Cell Signal 2014; 26:2773-81. [PMID: 25192910 DOI: 10.1016/j.cellsig.2014.08.020] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 08/17/2014] [Indexed: 12/11/2022]
Abstract
Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults with median survival time of 14.6 months. A small fraction of cancer stem cells (CSC) initiate and maintain tumors thus driving glioma tumorigenesis and being responsible for resistance to classical chemo- and radio-therapies. It is desirable to identify signaling pathways related to CSC to develop novel therapies to selectively target them. Transient receptor potential cation channel, subfamily M, member 7, also known as TRPM7 is a ubiquitous, Ca(2+) and Mg(2+) permeable ion channels that are special in being both an ion channel and a serine/threonine kinase. In studies of glioma cells silenced for TRPM7, we demonstrated that Notch (Notch1, JAG1, Hey2, and Survivin) and STAT3 pathways are down regulated in glioma cells grown in monolayer. Furthermore, phospho-STAT3, Notch target genes and CSC markers (ALDH1 and CD133) were significantly higher in spheroid glioma CSCs when compared with monolayer cultures. The results further show that tyrosine-phosphorylated STAT3 binds and activates the ALDH1 promoters in glioma cells. We found that TRMP7-induced upregulation of ALDH1 expression is associated with increases in ALDH1 activity and is detectable in stem-like cells when expanded as spheroid CSCs. Finally, TRPM7 promotes proliferation, migration and invasion of glioma cells. These demonstrate that TRPM7 activates JAK2/STAT3 and/or Notch signaling pathways and leads to increased cell proliferation and migration. These findings for the first time demonstrates that TRPM7 (1) activates a previously unrecognized STAT3→ALDH1 pathway, and (2) promotes the induction of ALDH1 activity in glioma cells.
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Abstract
SIGNIFICANCE Environmental and endogenous reactive species such as reactive oxygen species (ROS), reactive nitrogen species (RNS), and other electrophiles are not only known to exert toxic effects on organisms, but are also emerging as molecules that mediate cell signaling responses. However, the mechanisms underlying this cellular redox signaling by reactive species remains largely uncharacterized. RECENT ADVANCES Ca2+-permeable cation channels encoded by the transient receptor potential (trp) gene superfamily are characterized by a wide variety of activation triggers that act from outside and inside the cell. Recent studies have revealed that multiple TRP channels sense reactive species and induce diverse physiological and pathological responses, such as cell death, chemokine production, and pain transduction. TRP channels sense reactive species either indirectly through second messengers or directly via oxidative modification of cysteine residues. In this review, we describe the activation mechanisms and biological roles of redox-sensitive TRP channels, including TRPM2, TRPM7, TRPC5, TRPV1, and TRPA1. CRITICAL ISSUES The sensitivity of TRP channels to reactive species in vitro has been well characterized using molecular and pharmacological approaches. However, the precise activation mechanism(s) and in vivo function(s) of ROS/RNS-sensitive TRP channels remain elusive. FUTURE DIRECTIONS Redox sensitivity of TRP channels has been shown to mediate previously unexplained biological phenomena and is involved in various pathologies. Understanding the physiological significance and activation mechanisms of TRP channel regulation by reactive species may lead to TRP channels becoming viable pharmacological targets, and modulators of these channels may offer therapeutic options for previously untreatable diseases.
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Affiliation(s)
- Daisuke Kozai
- 1 Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University , Kyoto, Japan
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Liu D, Xiong S, Zhu Z. Imbalance and dysfunction of transient receptor potential channels contribute to the pathogenesis of hypertension. SCIENCE CHINA-LIFE SCIENCES 2014; 57:818-25. [DOI: 10.1007/s11427-014-4713-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/11/2014] [Indexed: 10/24/2022]
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Yee NS, Kazi AA, Yee RK. Cellular and Developmental Biology of TRPM7 Channel-Kinase: Implicated Roles in Cancer. Cells 2014; 3:751-77. [PMID: 25079291 PMCID: PMC4197629 DOI: 10.3390/cells3030751] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 12/29/2022] Open
Abstract
The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed cation-permeable ion channel with intrinsic kinase activity that plays important roles in various physiological functions. Biochemical and electrophysiological studies, in combination with molecular analyses of TRPM7, have generated insights into its functions as a cellular sensor and transducer of physicochemical stimuli. Accumulating evidence indicates that TRPM7 channel-kinase is essential for cellular processes, such as proliferation, survival, differentiation, growth, and migration. Experimental studies in model organisms, such as zebrafish, mouse, and frog, have begun to elucidate the pleiotropic roles of TRPM7 during embryonic development from gastrulation to organogenesis. Aberrant expression and/or activity of the TRPM7 channel-kinase have been implicated in human diseases including a variety of cancer. Studying the functional roles of TRPM7 and the underlying mechanisms in normal cells and developmental processes is expected to help understand how TRPM7 channel-kinase contributes to pathogenesis, such as malignant neoplasia. On the other hand, studies of TRPM7 in diseases, particularly cancer, will help shed new light in the normal functions of TRPM7 under physiological conditions. In this article, we will provide an updated review of the structural features and biological functions of TRPM7, present a summary of current knowledge of its roles in development and cancer, and discuss the potential of TRPM7 as a clinical biomarker and therapeutic target in malignant diseases.
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Affiliation(s)
- Nelson S Yee
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Abid A Kazi
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Rosemary K Yee
- Schreyer Honors College, Pennsylvania State University, University Park, PA 16802, USA; Penn State Harrisburg School of Humanities, Pennsylvania State University, Middletown, PA 17057, USA.
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Zhou W, Guo S, Xiong Z, Liu M. Oncogenic role and therapeutic target of transient receptor potential melastatin 7 channel in malignancy. Expert Opin Ther Targets 2014; 18:1177-96. [DOI: 10.1517/14728222.2014.940894] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Krapivinsky G, Krapivinsky L, Manasian Y, Clapham DE. The TRPM7 chanzyme is cleaved to release a chromatin-modifying kinase. Cell 2014; 157:1061-72. [PMID: 24855944 DOI: 10.1016/j.cell.2014.03.046] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 01/13/2014] [Accepted: 03/12/2014] [Indexed: 02/05/2023]
Abstract
TRPM7 is a ubiquitous ion channel and kinase, a unique "chanzyme," required for proper early embryonic development. It conducts Zn(2+), Mg(2+), and Ca(2+) as well as monovalent cations and contains a functional serine/threonine kinase at its carboxyl terminus. Here, we show that in normal tissues and cell lines, the kinase is proteolytically cleaved from the channel domain in a cell-type-specific manner. These TRPM7 cleaved kinase fragments (M7CKs) translocate to the nucleus and bind multiple components of chromatin-remodeling complexes, including Polycomb group proteins. In the nucleus, the kinase phosphorylates specific serines/threonines of histones. M7CK-dependent phosphorylation of H3Ser10 at promoters of TRPM7-dependent genes correlates with their activity. We also demonstrate that cytosolic free [Zn(2+)] is TRPM7 dependent and regulates M7CK binding to transcription factors containing zinc-finger domains. These findings suggest that TRPM7-mediated modulation of intracellular Zn(2+) concentration couples ion-channel signaling to epigenetic chromatin covalent modifications that affect gene expression patterns. PAPERCLIP:
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Affiliation(s)
- Grigory Krapivinsky
- Howard Hughes Medical Institute, Department of Cardiology, Boston Children's Hospital, Enders Building 1309, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Luba Krapivinsky
- Howard Hughes Medical Institute, Department of Cardiology, Boston Children's Hospital, Enders Building 1309, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Yunona Manasian
- Howard Hughes Medical Institute, Department of Cardiology, Boston Children's Hospital, Enders Building 1309, 320 Longwood Avenue, Boston, MA 02115, USA
| | - David E Clapham
- Howard Hughes Medical Institute, Department of Cardiology, Boston Children's Hospital, Enders Building 1309, 320 Longwood Avenue, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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71
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Shen B, Sun L, Zheng H, Yang D, Zhang J, Zhang Q. The association between single-nucleotide polymorphisms of TRPM7 gene and breast cancer in Han Population of Northeast China. Med Oncol 2014; 31:51. [PMID: 24952306 PMCID: PMC4079941 DOI: 10.1007/s12032-014-0051-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/24/2014] [Indexed: 01/24/2023]
Abstract
Breast cancer is one of the most common cancer and remains the leading cause of cancer-related deaths in women. There is increasing evidence suggesting that TRPM7 plays a pivotal role in breast cancer progression and metastasis. In this study, a case-control study was carried out to investigate the effects of SNPs in TRPM7 genes in the development of breast cancer in Han Population of Northeast China. A total of six SNPs (rs8042919, rs4775899, rs11635825, rs7173321, rs616256, and rs11070795) were chosen and genotyped. Genotypes were analyzed using a single-base primer extension assay. Chi-square (χ (2)) test was used to analyze statistical difference between control and patient groups in genotype and allele frequencies. The genotype-specific risks and allele frequencies of haplotypes in breast cancer patients and controls were estimated by OR and 95 % confidence intervals. The G allele of rs8042919 was associated with a reduced disease risk. The G allele of rs7173321 and particularly its homozygous GG genotype are associated with an increased breast cancer risk. Two of the TRPM7 SNPs (rs8042919 and rs7173321) are associated with breast cancer patients in Han Population of Northeast China.
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Affiliation(s)
- Bin Shen
- Breast Surgery of the Second Affiliated Hospital of Harbin Medical University, No. 246 Xuefu Road Nangang Strict, Harbin, 150086, Heilongjiang Province, China
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Li X, Wang X, Wang Y, Li X, Huang C, Li J. Inhibition of transient receptor potential melastatin 7 (TRPM7) channel induces RA FLSs apoptosis through endoplasmic reticulum (ER) stress. Clin Rheumatol 2014; 33:1565-74. [DOI: 10.1007/s10067-014-2599-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/12/2014] [Accepted: 03/29/2014] [Indexed: 01/07/2023]
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Kim MC, Lee HJ, Lim B, Ha KT, Kim SY, So I, Kim BJ. Quercetin induces apoptosis by inhibiting MAPKs and TRPM7 channels in AGS cells. Int J Mol Med 2014; 33:1657-63. [PMID: 24647664 DOI: 10.3892/ijmm.2014.1704] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 03/13/2014] [Indexed: 11/05/2022] Open
Abstract
The worldwide incidence and mortality rate of gastric cancer remain high, and thus, novel treatment concepts are required. Quercetin, a bioflavonoid, has been proposed to have anti-cancer properties. The aim of this study was to determine the nature of the apoptotic mechanisms responsible for the effects of quercetin on AGS cells (a commonly used human gastric adenocarcinoma cell line). AGS cell viability was assessed by MTT assay and flow cytometric analysis, mitochondrial membrane depolarization was assessed, and caspase-3 was used to determine the involvement of apoptosis. Whole-cell configuration patch-clamp experiments were used to regulate the transient receptor potential melastatin (TRPM)7 channels. To investigate the signaling pathway of quercetin-induced apoptosis in the AGS cells, western blot analysis and MTT assay were performed. Quercetin was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 kinase inhibitor), SP600125 (a JNK inhibitor) and PD98059 (an ERK inhibitor). In addition, quercetin inhibited TRPM7 currents in the AGS cells and in human embryo kidney (HEK)293 cells which overexpress TRPM7 channels. Furthermore, treatment with quercetin increased the apoptosis of HEK293 cells, which overexpress TRPM7, indicating that the upregulation of TRPM7 channels underlies quercetin-induced cell death. These results suggest that quercetin plays an important pathophysiological role in AGS cells through mitogen‑activated protein kinase (MAPK) signaling pathways and TRPM7 channels, and that quercetin has potential as a pharmacological agent for the treatment of gastric cancer.
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Affiliation(s)
- Min Chul Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
| | - Hee Jung Lee
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
| | - Bora Lim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
| | - Ki-Tae Ha
- Division of Applied Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
| | - Sung Young Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
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74
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Hofmann T, Schäfer S, Linseisen M, Sytik L, Gudermann T, Chubanov V. Activation of TRPM7 channels by small molecules under physiological conditions. Pflugers Arch 2014; 466:2177-89. [PMID: 24633576 DOI: 10.1007/s00424-014-1488-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 02/17/2014] [Accepted: 02/18/2014] [Indexed: 01/07/2023]
Abstract
Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) is a cation channel covalently linked to a protein kinase domain. TRPM7 is ubiquitously expressed and regulates key cellular processes such as Mg(2+) homeostasis, motility, and proliferation. TRPM7 is involved in anoxic neuronal death, cardiac fibrosis, and tumor growth. The goal of this work was to identify small molecule activators of the TRPM7 channel and investigate their mechanism of action. We used an aequorin bioluminescence-based assay to screen for activators of the TRPM7 channel. Valid candidates were further characterized using patch clamp electrophysiology. We identified 20 drug-like compounds with various structural backbones that can activate the TRPM7 channel. Among them, the δ opioid antagonist naltriben was studied in greater detail. Naltriben's action was selective among the TRP channels tested. Naltriben activates TRPM7 currents without prior depletion of intracellular Mg(2+) even under conditions of low PIP2. Moreover, naltriben interfered with the effect of the TRPM7 inhibitor NS8593. Finally, our experiments with TRPM7 variants carrying mutations in the pore, TRP, and kinase domains indicate that the site of TRPM7 activation by this small-molecule ligand is most likely located in or near the TRP domain. In conclusion, we identified the first organic small-molecule activators of TRPM7 channels, thus providing new experimental tools to study TRPM7 function in native cellular environments.
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Affiliation(s)
- T Hofmann
- Philipps-Universität Marburg, Klinik für Innere Medizin/Nephrologie, Baldingerstraße 1, 35043, Marburg, Germany,
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Park HS, Hong C, Kim BJ, So I. The Pathophysiologic Roles of TRPM7 Channel. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 18:15-23. [PMID: 24634592 PMCID: PMC3951819 DOI: 10.4196/kjpp.2014.18.1.15] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/08/2013] [Accepted: 11/18/2013] [Indexed: 02/07/2023]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a member of the melastatin-related subfamily and contains a channel and a kinase domain. TRPM7 is known to be associated with cell proliferation, survival, and development. It is ubiquitously expressed, highly permeable to Mg2+ and Ca2+, and its channel activity is negatively regulated by free Mg2+ and Mg-complexed nucleotides. Recent studies have investigated the relationships between TRPM7 and a number of diseases. TRPM7 regulates cell proliferation in several cancers, and is associated with ischemic cell death and vascular smooth muscle cell (VSMC) function. This review discusses the physiologic and pathophysiologic functions and significance of TRPM7 in several diseases.
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Affiliation(s)
- Hyun Soo Park
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Korea
| | - Chansik Hong
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
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76
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Proton-sensitive cation channels and ion exchangers in ischemic brain injury: new therapeutic targets for stroke? Prog Neurobiol 2014; 115:189-209. [PMID: 24467911 DOI: 10.1016/j.pneurobio.2013.12.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/28/2013] [Accepted: 12/24/2013] [Indexed: 12/13/2022]
Abstract
Ischemic brain injury results from complicated cellular mechanisms. The present therapy for acute ischemic stroke is limited to thrombolysis with the recombinant tissue plasminogen activator (rtPA) and mechanical recanalization. Therefore, a better understanding of ischemic brain injury is needed for the development of more effective therapies. Disruption of ionic homeostasis plays an important role in cell death following cerebral ischemia. Glutamate receptor-mediated ionic imbalance and neurotoxicity have been well established in cerebral ischemia after stroke. However, non-NMDA receptor-dependent mechanisms, involving acid-sensing ion channel 1a (ASIC1a), transient receptor potential melastatin 7 (TRPM7), and Na(+)/H(+) exchanger isoform 1 (NHE1), have recently emerged as important players in the dysregulation of ionic homeostasis in the CNS under ischemic conditions. These H(+)-sensitive channels and/or exchangers are expressed in the majority of cell types of the neurovascular unit. Sustained activation of these proteins causes excessive influx of cations, such as Ca(2+), Na(+), and Zn(2+), and leads to ischemic reperfusion brain injury. In this review, we summarize recent pre-clinical experimental research findings on how these channels/exchangers are regulated in both in vitro and in vivo models of cerebral ischemia. The blockade or transgenic knockdown of these proteins was shown to be neuroprotective in these ischemia models. Taken together, these non-NMDA receptor-dependent mechanisms may serve as novel therapeutic targets for stroke intervention.
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77
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Zhu Y, Men R, Wen M, Hu X, Liu X, Yang L. Blockage of TRPM7 channel induces hepatic stellate cell death through endoplasmic reticulum stress-mediated apoptosis. Life Sci 2014; 94:37-44. [DOI: 10.1016/j.lfs.2013.10.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 09/20/2013] [Accepted: 10/24/2013] [Indexed: 12/20/2022]
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78
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Borowiec AS, Bidaux G, Pigat N, Goffin V, Bernichtein S, Capiod T. Calcium channels, external calcium concentration and cell proliferation. Eur J Pharmacol 2013; 739:19-25. [PMID: 24291106 DOI: 10.1016/j.ejphar.2013.10.072] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/28/2013] [Accepted: 10/17/2013] [Indexed: 11/16/2022]
Abstract
Evidence for a role for calcium channel proteins in cell proliferation is numerous suggesting that calcium influx is essential in this physiological process. Several studies in the past thirty years have demonstrated that calcium channel expression levels are determinant in cell proliferation. Voltage-gated, store-operated, second messengers and receptor-operated calcium channels have been associated to cell proliferation. However, the relationship between calcium influx and cell proliferation can be uncoupled in transformed and cancer cells, resulting in an external calcium-independent proliferation. Thus, protein expression could be more important than channel function to trigger cell proliferation suggesting that additional channel functions may be responsible to reconcile calcium channel expression and cell proliferation. When needed, external calcium concentration is obviously important for calcium channel function but it also regulates calcium sensing receptor (CaSR) activity. CaSR can up- or down-regulate cell proliferation depending on physiological conditions. CaSR sensitivity to external calcium is within the 0.5 to 5 mM range and therefore, the role of these receptors in cell proliferation must be taken into account. We therefore suggest here that cell proliferation rates could depend on the relative balance between calcium influx and CaSR activation.
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Affiliation(s)
| | - Gabriel Bidaux
- INSERM U1003, LabEx ICST, Université Lille 1, Villeneuve d'Ascq F-59655, France
| | - Natascha Pigat
- INSERM U845, Research Center Growth and Signalling Research Center, Paris Descartes University, Sorbonne Paris Cité, Faculty of Medicine, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France
| | - Vincent Goffin
- INSERM U845, Research Center Growth and Signalling Research Center, Paris Descartes University, Sorbonne Paris Cité, Faculty of Medicine, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France
| | - Sophie Bernichtein
- INSERM U845, Research Center Growth and Signalling Research Center, Paris Descartes University, Sorbonne Paris Cité, Faculty of Medicine, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France
| | - Thierry Capiod
- INSERM U845, Research Center Growth and Signalling Research Center, Paris Descartes University, Sorbonne Paris Cité, Faculty of Medicine, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France.
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79
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Decker AR, McNeill MS, Lambert AM, Overton JD, Chen YC, Lorca RA, Johnson NA, Brockerhoff SE, Mohapatra DP, MacArthur H, Panula P, Masino MA, Runnels LW, Cornell RA. Abnormal differentiation of dopaminergic neurons in zebrafish trpm7 mutant larvae impairs development of the motor pattern. Dev Biol 2013; 386:428-39. [PMID: 24291744 DOI: 10.1016/j.ydbio.2013.11.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/01/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
Abstract
Transient receptor potential, melastatin-like 7 (Trpm7) is a combined ion channel and kinase implicated in the differentiation or function of many cell types. Early lethality in mice and frogs depleted of the corresponding gene impedes investigation of the functions of this protein particularly during later stages of development. By contrast, zebrafish trpm7 mutant larvae undergo early morphogenesis normally and thus do not have this limitation. The mutant larvae are characterized by multiple defects including melanocyte cell death, transient paralysis, and an ion imbalance that leads to the development of kidney stones. Here we report a requirement for Trpm7 in differentiation or function of dopaminergic neurons in vivo. First, trpm7 mutant larvae are hypomotile and fail to make a dopamine-dependent developmental transition in swim-bout length. Both of these deficits are partially rescued by the application of levodopa or dopamine. Second, histological analysis reveals that in trpm7 mutants a significant fraction of dopaminergic neurons lack expression of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Third, trpm7 mutants are unusually sensitive to the neurotoxin 1-methyl-4-phenylpyridinium, an oxidative stressor, and their motility is partially rescued by application of the iron chelator deferoxamine, an anti-oxidant. Finally, in SH-SY5Y cells, which model aspects of human dopaminergic neurons, forced expression of a channel-dead variant of TRPM7 causes cell death. In summary, a forward genetic screen in zebrafish has revealed that both melanocytes and dopaminergic neurons depend on the ion channel Trpm7. The mechanistic underpinning of this dependence requires further investigation.
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Affiliation(s)
- Amanda R Decker
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, United States
| | - Matthew S McNeill
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States
| | - Aaron M Lambert
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, United States
| | - Jeffrey D Overton
- UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States
| | - Yu-Chia Chen
- Neuroscience Center and Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland
| | - Ramón A Lorca
- Department of Pharmacology, University of Iowa, Iowa City, IA 52245, United States
| | - Nicolas A Johnson
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Susan E Brockerhoff
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Durga P Mohapatra
- Department of Pharmacology, University of Iowa, Iowa City, IA 52245, United States
| | - Heather MacArthur
- Department of Pharmacological and Physiological Science, St. Louis University, St. Louis, MO 63104, United States
| | - Pertti Panula
- Neuroscience Center and Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland
| | - Mark A Masino
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, United States
| | - Loren W Runnels
- UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States
| | - Robert A Cornell
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, United States; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States.
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Guilbert A, Gautier M, Dhennin-Duthille I, Rybarczyk P, Sahni J, Sevestre H, Scharenberg A, Ouadid-Ahidouch H. Transient receptor potential melastatin 7 is involved in oestrogen receptor-negative metastatic breast cancer cells migration through its kinase domain. Eur J Cancer 2013; 49:3694-707. [DOI: 10.1016/j.ejca.2013.07.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 06/24/2013] [Accepted: 07/10/2013] [Indexed: 11/25/2022]
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81
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Visser D, Langeslag M, Kedziora KM, Klarenbeek J, Kamermans A, Horgen FD, Fleig A, van Leeuwen FN, Jalink K. TRPM7 triggers Ca2+ sparks and invadosome formation in neuroblastoma cells. Cell Calcium 2013; 54:404-15. [PMID: 24176224 DOI: 10.1016/j.ceca.2013.09.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/27/2013] [Accepted: 09/28/2013] [Indexed: 11/28/2022]
Abstract
Cell migration depends on the dynamic formation and turnover of cell adhesions and is tightly controlled by actomyosin contractility and local Ca2+ signals. The divalent cation channel TRPM7 (Transient Receptor Potential cation channel, subfamily Melastatin, member 7) has recently received much attention as a regulator of cell adhesion, migration and (localized) Ca2+ signaling. Overexpression and knockdown of TRPM7 affects actomyosin contractility and the formation of cell adhesions such as invadosomes and focal adhesions, but the role of TRPM7-mediated Ca2+ signals herein is currently not understood. Using Total Internal Reflection Fluorescence (TIRF) Ca2+ fluorometry and a novel automated analysis routine we have addressed the role of Ca2+ in the control of invadosome dynamics in N1E-115 mouse neuroblastoma cells. We find that TRPM7 promotes the formation of highly repetitive and localized Ca2+ microdomains or "Ca2+ sparking hotspots" at the ventral plasma membrane. Ca2+ sparking appears strictly dependent on extracellular Ca2+ and is abolished by TRPM7 channel inhibitors such as waixenicin-A. TRPM7 inhibition also induces invadosome dissolution. However, invadosome formation is (functionally and spatially) dissociated from TRPM7-mediated Ca2+ sparks. Rather, our data indicate that TRPM7 affects actomyosin contractility and invadosome formation independent of Ca2+ influx.
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Affiliation(s)
- Daan Visser
- Division of Cell Biology I, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
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82
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Nam JH, Kim WK, Kim BJ. Sphingosine and FTY720 modulate pacemaking activity in interstitial cells of Cajal from mouse small intestine. Mol Cells 2013; 36:235-44. [PMID: 23912597 PMCID: PMC3887975 DOI: 10.1007/s10059-013-0091-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 12/15/2022] Open
Abstract
Interstitial cells of Cajal (ICCs) are the pacemakers of the gastrointestinal tract, and transient receptor potential melastatin type 7 (TRPM7) and Ca(2+) activated Cl(-) channels (ANO1) are candidate the generators of pacemaker potentials in ICCs. The effects of D-erythro-sphingosine (SPH) and structural analogues of SPH, that is, N,N-dimethyl-Derythro-sphingosine (N,N-DMS), FTY720, and FTY720-P on the pacemaking activities of ICCs were examined using the whole cell patch clamp technique. SPH, N,N-DMS, and FTY720 decreased the amplitudes of pacemaker potentials in ICC clusters, but resting membrane potentials displayed little change. Also, perfusing SPH, N,N-DMS, or FTY720 in the bath reduced both inward and outward TRPM7-like currents in single ICCs, and inhibited ANO1 currents. The another structural analogue of SPH, FTY720-P was ineffective at the pacemaker potentials in ICC clusters and the TRPM7-like currents in single ICCs. Furthermore, FTY720-P had no effect on ANO1. These results suggest that SPH, N,N-DMS, and FTY720 modulate the pacemaker activities of ICCs, and that TRPM7 and ANO1 channels affect intestinal motility.
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Affiliation(s)
| | | | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Korea
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83
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Inhibition of TRPM7 channels prevents proliferation and differentiation of human lung fibroblasts. Inflamm Res 2013; 62:961-70. [DOI: 10.1007/s00011-013-0653-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 05/16/2013] [Accepted: 07/31/2013] [Indexed: 12/24/2022] Open
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84
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Jiang HN, Zeng B, Zhang Y, Daskoulidou N, Fan H, Qu JM, Xu SZ. Involvement of TRPC channels in lung cancer cell differentiation and the correlation analysis in human non-small cell lung cancer. PLoS One 2013; 8:e67637. [PMID: 23840757 PMCID: PMC3695899 DOI: 10.1371/journal.pone.0067637] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/20/2013] [Indexed: 12/26/2022] Open
Abstract
The canonical transient receptor potential (TRPC) channels are Ca(2+)-permeable cationic channels controlling the Ca(2+) influx evoked by G protein-coupled receptor activation and/or by Ca(2+) store depletion. Here we investigate the involvement of TRPCs in the cell differentiation of lung cancer. The expression of TRPCs and the correlation to cancer differentiation grade in non-small cell lung cancer (NSCLC) were analyzed by real-time PCR and immunostaining using tissue microarrays from 28 patient lung cancer samples. The association of TRPCs with cell differentiation was also investigated in the lung cancer cell line A549 by PCR and Western blotting. The channel activity was monitored by Ca(2+) imaging and patch recording after treatment with all-trans-retinoic acid (ATRA). The expression of TRPC1, 3, 4 and 6 was correlated to the differentiation grade of NSCLC in patients, but there was no correlation to age, sex, smoking history and lung cancer cell type. ATRA upregulated TRPC3, TRPC4 and TRPC6 expression and enhanced Ca(2+) influx in A549 cells, however, ATRA showed no direct effect on TRPC channels. Inhibition of TRPC channels by pore-blocking antibodies decreased the cell mitosis, which was counteracted by chronic treatment with ATRA. Blockade of TRPC channels inhibited A549 cell proliferation, while overexpression of TRPCs increased the proliferation. We conclude that TRPC expression correlates to lung cancer differentiation. TRPCs mediate the pharmacological effect of ATRA and play important roles in regulating lung cancer cell differentiation and proliferation, which gives a new understanding of lung cancer biology and potential anti-cancer therapy.
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Affiliation(s)
- Hong-Ni Jiang
- Department of Pulmonary Medicine, Zhongshan Hospital, School of Medicine, Fudan University, Shanghai, China
- Centre for Cardiovascular and Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Bo Zeng
- Centre for Cardiovascular and Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Yi Zhang
- Department of Thoracic Surgery, Zhongshan Hospital, School of Medicine, Fudan University, Shanghai, China
| | - Nikoleta Daskoulidou
- Centre for Cardiovascular and Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Hong Fan
- Department of Thoracic Surgery, Zhongshan Hospital, School of Medicine, Fudan University, Shanghai, China
| | - Jie-Ming Qu
- Department of Pulmonary Medicine, Huadong Hospital, School of Medicine, Fudan University, Shanghai, China
- * E-mail: (JMQ); (SZX)
| | - Shang-Zhong Xu
- Centre for Cardiovascular and Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
- * E-mail: (JMQ); (SZX)
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85
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Kim BJ. Involvement of melastatin type transient receptor potential 7 channels in ginsenoside Rd-induced apoptosis in gastric and breast cancer cells. J Ginseng Res 2013; 37:201-9. [PMID: 23717173 PMCID: PMC3659640 DOI: 10.5142/jgr.2013.37.201] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 12/05/2012] [Accepted: 12/05/2012] [Indexed: 01/16/2023] Open
Abstract
Ginsenoside, one of the active ingredients of Panax ginseng, has a variety of physiologic and pharmacologic effects. The purpose of this study was to explore the effects of ginsenoside Rd (G-Rd) on melastatin type transient receptor potential 7 (TRPM7) channels with respect to the proliferation and survival of AGS and MCF-7 cells (a gastric and a breast cancer cell line, respectively). AGS and MCF-7 cells were treated with different concentrations of G-Rd, and caspase-3 activities, mitochondrial depolarizations, and sub-G1 fractions were analyzed to determine if cell death occurred by apoptosis. In addition, human embryonic kidney (HEK) 293 cells overexpressing TRPM7 channels were used to confirm the role of TRPM7 channels. G-Rd inhibited the proliferation and survival of AGS and MCF-7 cells and enhanced caspase-3 activity, mitochondrial depolarization, and sub-G1 populations. In addition, G-Rd inhibited TRPM7-like currents in AGS and MCF-7 cells and in TRPM7 channel overexpressing HEK 293 cells, as determined by whole cell voltage-clamp recordings. Furthermore, TRPM7 overexpression in HEK 293 cells promoted G-Rd induced cell death. These findings suggest that G-Rd inhibits the proliferation and survival of gastric and breast cancer cells by inhibiting TRPM7 channel activity.
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Affiliation(s)
- Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Korea
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86
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Abstract
Ischemic stroke is one of the leading causes of disability and death in the world. Elucidation of the underlying mechanisms associated with neuronal death during this detrimental process has been of significant interest in the field of research. One principle component vital to the maintenance of cellular integrity is the cytoskeleton. Studies suggest that abnormalities at the level of this fundamental structure are directly linked to adverse effects on cellular well-being, including cell death. In recent years, evidence has also emerged regarding an imperative role for the transient receptor potential (TRP) family member TRPM7 in the mediation of excitotoxic-independent neuronal demise. In this review, we will elaborate on the current knowledge and unique properties associated with the functioning of this structure. In addition, we will deliberate the involvement of distinct mechanistic pathways during TRPM7-dependent cell death, including modifications at the level of the cytoskeleton.
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Affiliation(s)
- Suhail Asrar
- Department of Biological Sciences, University of Toronto, Scarborough, ON, Canada
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87
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Chubanov V, Mederos y Schnitzler M, Meißner M, Schäfer S, Abstiens K, Hofmann T, Gudermann T. Natural and synthetic modulators of SK (K(ca)2) potassium channels inhibit magnesium-dependent activity of the kinase-coupled cation channel TRPM7. Br J Pharmacol 2012; 166:1357-76. [PMID: 22242975 DOI: 10.1111/j.1476-5381.2012.01855.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bifunctional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. TRPM7 is essential for proliferation and cell growth. Up-regulation of TRPM7 function is involved in anoxic neuronal death, cardiac fibrosis and tumour cell proliferation. The goal of this work was to identify non-toxic inhibitors of the TRPM7 channel and to assess the effect of blocking endogenous TRPM7 currents on the phenotype of living cells. EXPERIMENTAL APPROACH We developed an aequorin bioluminescence-based assay of TRPM7 channel activity and performed a hypothesis-driven screen for inhibitors of the channel. The candidates identified were further assessed electrophysiologically and in cell biological experiments. KEY RESULTS TRPM7 currents were inhibited by modulators of small conductance Ca²⁺ -activated K⁺ channels (K(Ca)2.1-2.3; SK) channels, including the antimalarial plant alkaloid quinine, CyPPA, dequalinium, NS8593, SKA31 and UCL 1684. The most potent compound NS8593 (IC₅₀ 1.6 µM) specifically targeted TRPM7 as compared with other TRP channels, interfered with Mg²⁺ -dependent regulation of TRPM7 channel and inhibited the motility of cultured cells. NS8593 exhibited full and reversible block of native TRPM7-like currents in HEK 293 cells, freshly isolated smooth muscle cells, primary podocytes and ventricular myocytes. CONCLUSIONS AND IMPLICATIONS This study reveals a tight overlap in the pharmacological profiles of TRPM7 and K(Ca)2.1-2.3 channels. NS8593 acts as a negative gating modulator of TRPM7 and is well-suited to study functional features and cellular roles of endogenous TRPM7.
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Affiliation(s)
- V Chubanov
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Munich, Germany.
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88
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Oh HG, Chun YS, Kim Y, Youn SH, Shin S, Park MK, Kim TW, Chung S. Modulation of transient receptor potential melastatin related 7 channel by presenilins. Dev Neurobiol 2012; 72:865-77. [PMID: 22102510 DOI: 10.1002/dneu.22001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Presenilins (PS1 and PS2) are multifunctional proteins involved in a diverse array of molecular and cellular functions, including proteolysis, development, neurogenesis, synaptic plasticity, ion channel regulation and phospholipid metabolism. Mutations in presenilin genes are responsible for the majority of Familial Alzheimer disease (FAD). Consequently, FAD-associated mutations in genes encoding PS1 or PS2 lead to several key cellular phenotypes, including alterations in proteolysis of β-amyloid precursor protein (APP) and Ca(2+) entry. The mechanism underlying presenilin (PS)-mediated modulation of Ca(2+) entry remains to be determined. Our previous studies showed that the PS-dependent down-regulation of phosphatidylinositol-4,5-bisphosphate (PIP2) is attributable to the observed Ca(2+) deficits. In this study, we attempted to identify the ion channel that is subject to the PIP2 and PS-dependent modulation. We found that Ca(2+) or Zn(2+) entry via the transient receptor potential melastatin 7 (TRPM7) channel was attenuated by the presence of FAD-associated PS1 mutants, such as ΔE9 and L286V. TRPM7 has been implicated in Mg(2+) homeostasis and embryonic development. The intracellular delivery of PIP2 restored TRPM7-mediated Ca(2+) influx, indicating that the observed deficits in Ca(2+) entry are due to downregulation of PIP2. Conversely, PS1 and PS2 deficiency, previously shown to upregulate PIP2 levels, potentiated TRPM7-mediated Ca(2+) influx. PS-dependent changes in Ca(2+) influx could be neutralized by a TRPM7 channel blocker. Collectively, these results indicate that TRPM7 may underlie the Ca(2+) entry deficits observed in FAD-associated PS mutants and suggest that the normal function of PS involves regulation of TRPM7 through a PIP2-dependent mechanism.
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Affiliation(s)
- Hyun Geun Oh
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea
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89
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Kim BJ. Involvement of Transient Receptor Potential Melastatin 7 Channels in Sophorae Radix-induced Apoptosis in Cancer Cells: Sophorae Radix and TRPM7. J Pharmacopuncture 2012; 15:31-8. [PMID: 25780645 PMCID: PMC4331944 DOI: 10.3831/kpi.2012.15.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/10/2012] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Sophorae Radix (SR) plays a role in a number of physiologic and pharmacologic functions in many organs. OBJECTIVE The aim of this study was to clarify the potential role for transient receptor potential melastatin 7 (TRPM7) channels in SR-inhibited growth and survival of AGS and MCF-7 cells, the most common human gastric and breast adenocarcinoma cell lines. METHODS The AGS and the MCF-7 cells were treated with varying concentrations of SR. Analyses of the caspase-3 and - 9 activity, the mitochondrial depolarization and the poly (ADPribose) polymerase (PARP) cleavage were conducted to determine if AGS and MCF-7 cell death occured by apoptosis. TRPM7 channel blockers (Gd(3+) or 2-APB) and small interfering RNA (siRNA) were used in this study to confirm the role of TRPM7 channels. Furthermore, TRPM7 channels were overexpressed in human embryonic kidney (HEK) 293 cells to identify the role of TRPM7 channels in AGS and MCF-7 cell growth and survival. RESULTS The addition of SR to a culture medium inhibited AGS and MCF-7 cell growth and survival. Experimental results showed that the caspase-3 and -9 activity, the mitochondrial depolarization, and the degree of PARP cleavage was increased. TRPM7 channel blockade, either by Gd(3+) or 2-APB or by suppressing TRPM7 expression with small interfering RNA, blocked the SR-induced inhibition of cell growth and survival. Furthermore, TRPM7 channel overexpression in HEK 293 cells exacerbated SR-induced cell death. CONCLUSIONS These findings indicate that SR inhibits the growth and survival of gastric and breast cancer cells due to a blockade of the TRPM7 channel activity. Therefore, TRPM7 channels may play an important role in the survival of patients with gastric and breast cancer.
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Affiliation(s)
- Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan, Korea
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90
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Magnesium and its transporters in cancer: a novel paradigm in tumour development. Clin Sci (Lond) 2012; 123:417-27. [PMID: 22671428 DOI: 10.1042/cs20120086] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The relationship between magnesium and cancer is not as simple as could be assumed from the well-established requirement of magnesium for cell proliferation. Basic and pre-clinical studies indicate that magnesium deficiency can have both anti- and pro-tumour effects. In the present review, we briefly outline the new findings on the role of magnesium in angiogenesis and metastatization, and focus on the relationship between tumour cell proliferation and metabolic reprogramming, discussing how magnesium and its transporters are involved in these processes. The role of magnesium in cancer is also critically examined with regard to mitochondrial function, apoptosis and resistance to treatment. Finally, we bring together the latest experimental evidence indicating that alteration in the expression and/or activity of magnesium channels is a frequent finding in cancer cells and human tumour tissues examined to date, and we discuss the potential implications for developing novel diagnostic and therapeutic strategies.
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91
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Yee NS, Chan AS, Yee JD, Yee RK. TRPM7 and TRPM8 Ion Channels in Pancreatic Adenocarcinoma: Potential Roles as Cancer Biomarkers and Targets. SCIENTIFICA 2012; 2012:415158. [PMID: 24278689 PMCID: PMC3820452 DOI: 10.6064/2012/415158] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 07/08/2012] [Indexed: 06/01/2023]
Abstract
Transient receptor potential (TRP) ion channels are essential for normal functions and health by acting as molecular sensors and transducing various stimuli into cellular and physiological responses. Growing evidence has revealed that TRP ion channels play important roles in a wide range of human diseases, including malignancies. In light of recent discoveries, it has been found that TRP melastatin-subfamily members, TRPM7 and TRPM8, are required for normal and cancerous development of exocrine pancreas. We are currently investigating the mechanisms which mediate the functional roles of TRPM7 and TRPM8 and attempting to develop these ion channels as clinical biomarkers and therapeutic targets for achieving the goal of personalized therapy in pancreatic cancer.
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Affiliation(s)
- Nelson S. Yee
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Penn State Hershey Cancer Institute, Penn State Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033-0850, USA
| | - Ada S. Chan
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Penn State Hershey Cancer Institute, Penn State Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033-0850, USA
| | - Julian D. Yee
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Penn State Hershey Cancer Institute, Penn State Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033-0850, USA
| | - Rosemary K. Yee
- Penn State Harrisburg School of Humanities, Pennsylvania State University, Middletown, PA 17057, USA
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92
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Lam DH, Grant CE, Hill CE. Differential expression of TRPM7 in rat hepatoma and embryonic and adult hepatocytes. Can J Physiol Pharmacol 2012; 90:435-44. [DOI: 10.1139/y11-136] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
TRPM7 channels are implicated in cellular survival, proliferation, and differentiation. However, a profile of TRPM7 activity in a specific cell type has not been determined from embryonic to terminally differentiated state. Here, we characterized TRPM7 expression in a spectrum of rat liver cells at different developmental stages. Using the whole-cell patch clamp technique, TRPM7-like Na+ currents were identified in RLC-18 cells, a differentiated, proliferating hepatocellular line derived from day 17 embryonic rat liver. Currents were outwardly rectifying, enhanced in divalent-free solutions, and inhibited by intracellular Mg2+. Reverse transcription – polymerase chain reaction (RT–PCR) revealed that RLC-18 cells express both TRPM6 and TRPM7. However, mean currents were reduced almost 80% by 1 mmol/L 2-aminoethoxyphenylborate (2-APB) and were abolished in RLC-18 cells heterologously expressing a dominant negative TRPM7 construct, suggesting that TRPM7 is the major current carrier in these cells. Functional comparison showed that relative to terminally differentiated adult rat hepatocytes, currents were 1.8 and 3.9 times higher in, respectively, RLC-18 and WIF-B cells, a rat hepatoma – human fibroblast cross. Our results demonstrate that plasma membrane TRPM7 channels are more highly expressed in proliferating cells as compared with terminally differentiated and nondividing rat hepatocytes and suggest that downregulation of this channel is associated with hepatocellular differentiation.
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Affiliation(s)
- D. Hung Lam
- Departments of Biology and Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Caroline E. Grant
- Departments of Biology and Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Ceredwyn E. Hill
- Departments of Biology and Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada
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93
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Liu H, Li J, Huang Y, Huang C. Inhibition of transient receptor potential melastain 7 channel increases HSCs apoptosis induced by TRAIL. Life Sci 2012; 90:612-8. [PMID: 22406504 DOI: 10.1016/j.lfs.2012.02.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/03/2012] [Accepted: 02/17/2012] [Indexed: 11/16/2022]
Abstract
AIMS Transient receptor potential melastain 7 (TRPM7) channels are known to have a fundamental role in many cellular processes and pathology of various diseases. The objective of this study was to investigate the potential relationship between TRPM7 and the apoptosis of hepatic stellate cells (HSCs) induced by TNF-related apoptosis inducing-ligand (TRAIL). MAIN METHODS In this study, using a combination of Western blotting, RT-PCR and flow cytometric analysis, we investigated the influence and potential function of TRPM7 channels on the apoptosis induced by TRAIL in HSCs which is the key cell of formation of extracellular matrix (ECM) and is also the core link of occurrence of hepatic fibrosis (HF). KEY FINDINGS We observed significant expression of TRPM7 mRNA and protein in HSCs. Suppression of TRPM7 channels by 2-aminoethoxydiphenyl borate (2-APB) or Gd3+ not only markedly eliminated TRPM7 expression, but also increased the apoptosis of HSCs induced by TRAIL, a major apoptosis stimulator of HSCs. SIGNIFICANCE Our findings strongly suggest that TRPM7 channels are involved in the apoptosis of HSCs induced by TRAIL, probably by regulating the sensitivity of HSCs to TRAIL.
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Affiliation(s)
- Hong Liu
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, China
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94
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Mergler S, Cheng Y, Skosyrski S, Garreis F, Pietrzak P, Kociok N, Dwarakanath A, Reinach PS, Kakkassery V. Altered calcium regulation by thermosensitive transient receptor potential channels in etoposide-resistant WERI-Rb1 retinoblastoma cells. Exp Eye Res 2012; 94:157-73. [DOI: 10.1016/j.exer.2011.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 11/04/2011] [Accepted: 12/03/2011] [Indexed: 10/14/2022]
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95
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Mason MJ, Schaffner C, Floto RA, Teo QA. Constitutive expression of a Mg2+-inhibited K+ current and a TRPM7-like current in human erythroleukemia cells. Am J Physiol Cell Physiol 2011; 302:C853-67. [PMID: 22135214 DOI: 10.1152/ajpcell.00071.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Whole cell patch-clamp experiments were undertaken to define the basal K(+) conductance(s) in human erythroleukemia cells and its contribution to the setting of resting membrane potential. Experiments revealed a non-voltage-activated, noninactivating K(+) current. The magnitude of the current recorded under whole cell conditions was inhibited by an increase in free intracellular Mg(2+) concentration. Activation or inactivation of the Mg(2+)-inhibited K(+) current (MIP) was paralleled by activation or inactivation of a Mg(2+)-inhibited TRPM7-like current displaying characteristics indistinguishable from those reported for molecularly identified TRPM7 current. The MIP and TRPM7 currents were inhibited by 5-lipoxygenase inhibitors. However, inhibition of the MIP current was temporally distinct from inhibition of TRPM7 current, allowing for isolation of the MIP current. Isolation of the MIP conductance revealed a current reversing near the K(+) equilibrium potential, indicative of a highly K(+)-selective conductance. Consistent with this finding, coactivation of the nonselective cation current TRPM7 and the MIP current following dialysis with nominally Mg(2+)-free pipette solution resulted in hyperpolarized whole cell reversal potentials, consistent with an important role for the MIP current in the setting of a negative resting membrane potential. The MIP and TRPM7-like conductances were constitutively expressed under in vivo conditions of intracellular Mg(2+), as judged by their initial detection and subsequent inactivation following dialysis with a pipette solution containing 5 mM free Mg(2+). The MIP current was blocked in a voltage-dependent fashion by extracellular Cs(+) and, to a lesser degree, by Ba(2+) and was blocked by extracellular La(3+) and 2-aminoethoxydiphenyl borate. MIP currents were unaffected by blockers of ATP-sensitive K(+) channels, human ether-à-go-go-related gene current, and intermediate-conductance Ca(2+)-activated K(+) channels. In addition, the MIP current displayed characteristics distinct from conventional inwardly rectifying K(+) channels. A similar current was detected in the leukemic cell line CHRF-288-11, consistent with this current being more generally expressed in cells of leukemic origin.
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Affiliation(s)
- Michael J Mason
- Department of Physiology, Development, and Neuroscience, University of Cambridge, UK.
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96
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Gao H, Chen X, Du X, Guan B, Liu Y, Zhang H. EGF enhances the migration of cancer cells by up-regulation of TRPM7. Cell Calcium 2011; 50:559-68. [PMID: 21978419 DOI: 10.1016/j.ceca.2011.09.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 01/02/2023]
Abstract
Ion channels involved in the migration of tumor cells that is required for their invasion and metastasis. In this paper, we describe the interaction of TRPM7 channel and epidermal growth factor (EGF), an important player in cancer development in the migration of lung cancer cells. The TRPM7 currents in A549 cells were first characterized by means of electrophysiology, pharmacology and RNA interference. Removing Ca(2+) from the extracellular solution not only potentiated a large inward current, but also abolished the outward rectification. 200μM 2-APB inhibited the outward and the inward TRPM7 currents and at the same time restored the property of outward rectification. EGF greatly enhanced the migration of A549 cells, and also markedly up-regulated the membrane protein expression of TRPM7 and the amplitude of TRPM7 currents. Depressing the function of TRPM7 with RNA interference or pharmacological agents not only reversed the EGF-enhanced migration of A549 cells but also inhibited the basal migration of A549 cells in the absence of EGF. Thus it seems that TRPM7 plays a pivotal role in the migration of A549 cells induced by EGF and thus could be a potential therapeutic target in lung cancers.
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Affiliation(s)
- Haixia Gao
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, PR China
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97
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Harteneck C, Gollasch M. Pharmacological modulation of diacylglycerol-sensitive TRPC3/6/7 channels. Curr Pharm Biotechnol 2011; 12:35-41. [PMID: 20932261 PMCID: PMC3267170 DOI: 10.2174/138920111793937943] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 05/13/2010] [Indexed: 01/03/2023]
Abstract
Members of the classic type of transient receptor potential channels (TRPC) represent important molecules involved in hormonal signal transduction. TRPC3/6/7 channels are of particular interest as they are components of phospholipase C driven signalling pathways. Upon receptor-activation, G-protein-mediated stimulation of phospholipase C results in breakdown of phosphatidylinositides leading to increased intracellular diacylglycerol and inositol-trisphosphate levels. Diacylglycerol activates protein kinase C, but more interestingly diacylglycerol directly activates TRPC2/3/6/7 channels. Molecular cloning, expression and characterization of TRP channels enabled reassignment of traditional inhibitors of receptor-dependent calcium entry such as SKF-96365 and 2-APB as blockers of TRPC3/6/7 and several members of non-classic TRP channels. Furthermore, several enzyme inhibitors have also been identified as TRP channel blockers, such as ACA, a phospholipase A2 inhibitor, and W-7, a calmodulin antagonist. Finally, the naturally occurring secondary plant compound hyperforin has been identified as TRPC6-selective drug, providing an exciting proof of concept that it is possible to generate TRPC-selective channel modulators. The description of Pyr3 as the first TRPC3-selective inhibitor shows that not only nature but also man is able to generate TRP-selective modulators. The review sheds lights on the current knowledge and historical development of pharmacological modulators of TRPC3/6/7. Our analysis indicates that Pyr3 and hyperforin provide promising core structures for the development of new, selective and more potent modulators of TRPC3/6/7 activity.
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Affiliation(s)
- Christian Harteneck
- Institut für Pharmakologie & Toxikologie, Eberhard-Karls-Universitát, Wilhelmstraße 56, 72074 Tübingen, Germany.
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98
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Runnels LW. TRPM6 and TRPM7: A Mul-TRP-PLIK-cation of channel functions. Curr Pharm Biotechnol 2011; 12:42-53. [PMID: 20932259 DOI: 10.2174/138920111793937880] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/07/2010] [Indexed: 12/31/2022]
Abstract
Unique among ion channels, TRPM6 and TRPM7 garnered much interest upon their discovery as the first ion channels to possess their own kinase domain. Soon after their identification, the two proteins were quickly linked to the regulation of magnesium homeostasis. However, study of their physiological functions in mouse and zebrafish have revealed expanding roles for these channel-kinases that include skeletogenesis and melanopore formation, thymopoiesis, cell adhesion, and neural fold closure during early development. In addition, mutations in the TRPM6 gene constitute the underlying genetic defect in hypomagnesemia with secondary hypocalcemia, a rare autosomal-recessive disease characterized by low serum magnesium accompanied by hypocalcemia. Depletion of TRPM7 expression in brain, on the other hand, proved successful in mitigating much of the cellular devastation that accompanies oxygen-glucose deprivation during ischemia. The aim of this review is to summarize the data emerging from molecular genetic, biochemical, electrophysiological, and pharmacological studies of these unique channel-kinases.
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Affiliation(s)
- Loren W Runnels
- Department of Pharmacology, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
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99
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Hamaguchi Y, Tatematsu Y, Furukawa K, Matsubara T, Nakayama S. Imipramine inhibition of TRPM-like plasmalemmal Mg2+ transport in vascular smooth muscle cells. J Cell Mol Med 2011; 15:593-601. [PMID: 20132412 PMCID: PMC3922381 DOI: 10.1111/j.1582-4934.2010.01024.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Depression is associated with vascular disease, such as myocardial infarction and stroke. Pharmacological treatments may contribute to this association. On the other hand, Mg2+ deficiency is also known to be a risk factor for the same category of diseases. In the present study, we examined the effect of imipramine on Mg2+ homeostasis in vascular smooth muscle, especially via melastatin-type transient receptor potential (TRPM)-like Mg2+-permeable channels. The intracellular free Mg2+ concentration ([Mg2+]i) was measured using 31P-nuclear magnetic resonance (NMR) in porcine carotid arteries that express both TRPM6 and TRPM7, the latter being predominant. pHi and intracellular phosphorus compounds were simultaneously monitored. To rule out Na+-dependent Mg2+ transport, and to facilitate the activity of Mg2+-permeable channels, experiments were carried out in the absence of Na+ and Ca2+. Changing the extracellular Mg2+ concentration to 0 and 6 mM significantly decreased and increased [Mg2+]i, respectively, in a time-dependent manner. Imipramine statistically significantly attenuated both of the bi-directional [Mg2+]i changes under the Na+- and Ca2+-free conditions. This inhibitory effect was comparable in influx, and much more potent in efflux to that of 2-aminoethoxydiphenyl borate, a well-known blocker of TRPM7, a channel that plays a major role in cellular Mg2+ homeostasis. Neither [ATP]i nor pHi correlated with changes in [Mg2+]i. The results indicate that imipramine suppresses Mg2+-permeable channels presumably through a direct effect on the channel domain. This inhibitory effect appears to contribute, at least partially, to the link between antidepressants and the risk of vascular diseases.
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Affiliation(s)
- Yukihisa Hamaguchi
- Department of Cell Physiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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100
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Bae CYJ, Sun HS. TRPM7 in cerebral ischemia and potential target for drug development in stroke. Acta Pharmacol Sin 2011; 32:725-33. [PMID: 21552293 DOI: 10.1038/aps.2011.60] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Searching for effective pharmacological agents for stroke treatment has largely been unsuccessful. Despite initial excitement, antagonists for glutamate receptors, the most studied receptor channels in ischemic stroke, have shown insufficient neuroprotective effects in clinical trials. Outside the traditional glutamate-mediated excitotoxicity, recent evidence suggests few non-glutamate mechanisms, which may also cause ionic imbalance and cell death in cerebral ischemia. Transient receptor potential melastatin 7 (TRPM7) is a Ca(2+) permeable, non-selective cation channel that has recently gained attention as a potential cation influx pathway involved in ischemic events. Compelling new evidence from an in vivo study demonstrated that suppression of TRPM7 channels in adult rat brain in vivo using virally mediated gene silencing approach reduced delayed neuronal cell death and preserved neuronal functions in global cerebral ischemia. In this review, we will discuss the current understanding of the role of TRPM7 channels in physiology and pathophysiology as well as its therapeutic potential in stroke.
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