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Holderby KG, Kozak JA. Use of tetraethylammonium (TEA) and Tris loading for blocking TRPM7 channels in intact cells. Front Pharmacol 2024; 15:1341799. [PMID: 38659572 PMCID: PMC11039802 DOI: 10.3389/fphar.2024.1341799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Tetraethylammonium (TEA), a quaternary ammonium compound, is a well-known blocker of potassium channels belonging to various subfamilies, such as KV1-3, KCa1, 2 and prokaryotic KcsA. In many cases, TEA acts from the extracellular side by open pore blockade. TEA can also block transient receptor potential (TRP) cation channels, such as TRPM7, in a voltage-dependent manner. In human T lymphocytes, intracellular (cytosolic) TEA and its analog TMA (tetramethylammonium) inhibit TRPM7 channel currents in the outward but not inward direction. By contrast, intracellular Mg2+, protons and polyamines inhibit both outward and inward current components equally. Likewise, the majority of available pharmacological tools inhibit TRPM7 channels in a voltage-independent manner. Since TRPM7 is a steeply outwardly rectifying conductance, voltage-dependent blockers can be useful for studying the cellular functions of this channel. TRPM7 protein is endogenously expressed in diverse cell lines, including HEK, HeLa, CHO, RBL and Jurkat. Using patch-clamp electrophysiology, we found that incubating HEK293 and Jurkat T cells overnight in the presence of 20 mM TEA-Cl, resulted in the nearly complete blockade of whole-cell TRPM7 outward current, measured at break-in. By contrast, the inward current was unchanged in TEA-loaded cells. The blockade was fully reversible after washout of intracellular solution in whole-cell but not in perforated-patch recording configurations. Overnight incubation with 20 mM TMA-Cl resulted in a more modest blockade of the outward TRPM7 current. Internal 129 mM TMA and TEA eliminated most of the outward current. TEA uptake in transfected HEK293 cells led to blockade of recombinant murine TRPM7 and the Mg2+ and pH insensitive Ser1107Arg variant. Unexpectedly, Tris-HCl, a widely used pH buffer, could similarly be loaded into Jurkat and HEK cells, and preferentially blocked outward TRPM7 currents. 20 mM and 129 mM Tris in the internal solution blocked TRPM7 current in outward but not inward direction. Voltage-dependent channel blockade by TEA, TMA and Tris loading will be useful for studying the properties and functions of TRPM7-mediated ion transport in intact cells.
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Affiliation(s)
- Katherine G. Holderby
- Undergraduate Program in Physiology and Neuroscience, Dayton, OH, United States
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, United States
| | - J. Ashot Kozak
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, United States
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Xie Z, Abumaria N. Effect of truncation on TRPM7 channel activity. Channels (Austin) 2023; 17:2200874. [PMID: 37040321 PMCID: PMC10761173 DOI: 10.1080/19336950.2023.2200874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 04/04/2023] [Indexed: 04/12/2023] Open
Abstract
Transient receptor potential melastatin-like 7 (TRPM7) is a key player in various physiological and pathological processes. TRPM7 channel activity is regulated by different factors. The effects of cleavage of different domains on channel activity remain unknown. Here, we constructed several TRPM7 clones and explored the effects of truncating the mouse TRPM7 at different locations on the ion channel activity in two cell lines. We compared the clones' activity with the full-length TRPM7 and the native TRPM7 in transfected and untransfected cells. We also expressed fluorescently tagged truncated clones to examine their protein stability and membrane targeting. We found that truncating the kinase domain induced reduction in TRPM7 channel activity. Further truncations beyond the kinase (serine/threonine rich domain and/or coiled-coil domain) did not result in further reductions in channel activity. Two truncated clones lacking the TRP domain or the melastatin homology domain had a completely nonfunctional channel apparently due to disruption of protein stability. We identified the shortest structure of TRPM7 with measurable channel activity. We found that the truncated TRPM7 containing only S5 and S6 domains retained some channel activity. Adding the TRP domain to the S5-S6 resulted in a significant increase in channel activity. Finally, our analysis showed that TRPM7 outward currents are more sensitive to truncations than inward currents. Our data provide insights on the effects of truncating TRPM7 at different locations on the channel functions, highlighting the importance of different domains in impacting channel activity, protein stability, and/or membrane targeting.
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Affiliation(s)
- Zhuqing Xie
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Nashat Abumaria
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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Okada Y, Numata T, Sabirov RZ, Kashio M, Merzlyak PG, Sato-Numata K. Cell death induction and protection by activation of ubiquitously expressed anion/cation channels. Part 3: the roles and properties of TRPM2 and TRPM7. Front Cell Dev Biol 2023; 11:1246955. [PMID: 37842082 PMCID: PMC10576435 DOI: 10.3389/fcell.2023.1246955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023] Open
Abstract
Cell volume regulation (CVR) is a prerequisite for animal cells to survive and fulfill their functions. CVR dysfunction is essentially involved in the induction of cell death. In fact, sustained normotonic cell swelling and shrinkage are associated with necrosis and apoptosis, and thus called the necrotic volume increase (NVI) and the apoptotic volume decrease (AVD), respectively. Since a number of ubiquitously expressed ion channels are involved in the CVR processes, these volume-regulatory ion channels are also implicated in the NVI and AVD events. In Part 1 and Part 2 of this series of review articles, we described the roles of swelling-activated anion channels called VSOR or VRAC and acid-activated anion channels called ASOR or PAC in CVR and cell death processes. Here, Part 3 focuses on therein roles of Ca2+-permeable non-selective TRPM2 and TRPM7 cation channels activated by stress. First, we summarize their phenotypic properties and molecular structure. Second, we describe their roles in CVR. Since cell death induction is tightly coupled to dysfunction of CVR, third, we focus on their participation in the induction of or protection against cell death under oxidative, acidotoxic, excitotoxic, and ischemic conditions. In this regard, we pay attention to the sensitivity of TRPM2 and TRPM7 to a variety of stress as well as to their capability to physicall and functionally interact with other volume-related channels and membrane enzymes. Also, we summarize a large number of reports hitherto published in which TRPM2 and TRPM7 channels are shown to be involved in cell death associated with a variety of diseases or disorders, in some cases as double-edged swords. Lastly, we attempt to describe how TRPM2 and TRPM7 are organized in the ionic mechanisms leading to cell death induction and protection.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences (NIPS), Okazaki, Japan
- Department of Integrative Physiology, Graduate School of Medicine, AkitaUniversity, Akita, Japan
- Department of Physiology, School of Medicine, Aichi Medical Uniersity, Nagakute, Japan
- Department of Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Cardiovascular Research Institute, Yokohama City University, Yokohama, Japan
| | - Tomohiro Numata
- Department of Integrative Physiology, Graduate School of Medicine, AkitaUniversity, Akita, Japan
| | - Ravshan Z. Sabirov
- Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Makiko Kashio
- National Institute for Physiological Sciences (NIPS), Okazaki, Japan
- Department of Physiology, School of Medicine, Aichi Medical Uniersity, Nagakute, Japan
| | - Peter G. Merzlyak
- Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Kaori Sato-Numata
- Department of Integrative Physiology, Graduate School of Medicine, AkitaUniversity, Akita, Japan
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Cheng XY, Li SF, Chen Y, Zhao YJ, Hu W, Lu C, Zhou RP. Transient receptor potential melastatin 7 and their modulators. Eur J Pharmacol 2022; 931:175180. [DOI: 10.1016/j.ejphar.2022.175180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/20/2022] [Accepted: 08/01/2022] [Indexed: 11/03/2022]
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Franken GAC, Huynen MA, Martínez-Cruz LA, Bindels RJM, de Baaij JHF. Structural and functional comparison of magnesium transporters throughout evolution. Cell Mol Life Sci 2022; 79:418. [PMID: 35819535 PMCID: PMC9276622 DOI: 10.1007/s00018-022-04442-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/22/2022] [Accepted: 06/21/2022] [Indexed: 12/16/2022]
Abstract
Magnesium (Mg2+) is the most prevalent divalent intracellular cation. As co-factor in many enzymatic reactions, Mg2+ is essential for protein synthesis, energy production, and DNA stability. Disturbances in intracellular Mg2+ concentrations, therefore, unequivocally result in delayed cell growth and metabolic defects. To maintain physiological Mg2+ levels, all organisms rely on balanced Mg2+ influx and efflux via Mg2+ channels and transporters. This review compares the structure and the function of prokaryotic Mg2+ transporters and their eukaryotic counterparts. In prokaryotes, cellular Mg2+ homeostasis is orchestrated via the CorA, MgtA/B, MgtE, and CorB/C Mg2+ transporters. For CorA, MgtE, and CorB/C, the motifs that form the selectivity pore are conserved during evolution. These findings suggest that CNNM proteins, the vertebrate orthologues of CorB/C, also have Mg2+ transport capacity. Whereas CorA and CorB/C proteins share the gross quaternary structure and functional properties with their respective orthologues, the MgtE channel only shares the selectivity pore with SLC41 Na+/Mg2+ transporters. In eukaryotes, TRPM6 and TRPM7 Mg2+ channels provide an additional Mg2+ transport mechanism, consisting of a fusion of channel with a kinase. The unique features these TRP channels allow the integration of hormonal, cellular, and transcriptional regulatory pathways that determine their Mg2+ transport capacity. Our review demonstrates that understanding the structure and function of prokaryotic magnesiotropic proteins aids in our basic understanding of Mg2+ transport.
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Affiliation(s)
- G A C Franken
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - M A Huynen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - L A Martínez-Cruz
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park, Derio, 48160, Bizkaia, Spain
| | - R J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - J H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Audero MM, Prevarskaya N, Fiorio Pla A. Ca2+ Signalling and Hypoxia/Acidic Tumour Microenvironment Interplay in Tumour Progression. Int J Mol Sci 2022; 23:ijms23137377. [PMID: 35806388 PMCID: PMC9266881 DOI: 10.3390/ijms23137377] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 01/18/2023] Open
Abstract
Solid tumours are characterised by an altered microenvironment (TME) from the physicochemical point of view, displaying a highly hypoxic and acidic interstitial fluid. Hypoxia results from uncontrolled proliferation, aberrant vascularization and altered cancer cell metabolism. Tumour cellular apparatus adapts to hypoxia by altering its metabolism and behaviour, increasing its migratory and metastatic abilities by the acquisition of a mesenchymal phenotype and selection of aggressive tumour cell clones. Extracellular acidosis is considered a cancer hallmark, acting as a driver of cancer aggressiveness by promoting tumour metastasis and chemoresistance via the selection of more aggressive cell phenotypes, although the underlying mechanism is still not clear. In this context, Ca2+ channels represent good target candidates due to their ability to integrate signals from the TME. Ca2+ channels are pH and hypoxia sensors and alterations in Ca2+ homeostasis in cancer progression and vascularization have been extensively reported. In the present review, we present an up-to-date and critical view on Ca2+ permeable ion channels, with a major focus on TRPs, SOCs and PIEZO channels, which are modulated by tumour hypoxia and acidosis, as well as the consequent role of the altered Ca2+ signals on cancer progression hallmarks. We believe that a deeper comprehension of the Ca2+ signalling and acidic pH/hypoxia interplay will break new ground for the discovery of alternative and attractive therapeutic targets.
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Affiliation(s)
- Madelaine Magalì Audero
- U1003—PHYCEL—Laboratoire de Physiologie Cellulaire, Inserm, University of Lille, Villeneuve d’Ascq, 59000 Lille, France; (M.M.A.); (N.P.)
- Laboratory of Cellular and Molecular Angiogenesis, Department of Life Sciences and Systems Biology, University of Turin, 10123 Turin, Italy
| | - Natalia Prevarskaya
- U1003—PHYCEL—Laboratoire de Physiologie Cellulaire, Inserm, University of Lille, Villeneuve d’Ascq, 59000 Lille, France; (M.M.A.); (N.P.)
| | - Alessandra Fiorio Pla
- U1003—PHYCEL—Laboratoire de Physiologie Cellulaire, Inserm, University of Lille, Villeneuve d’Ascq, 59000 Lille, France; (M.M.A.); (N.P.)
- Laboratory of Cellular and Molecular Angiogenesis, Department of Life Sciences and Systems Biology, University of Turin, 10123 Turin, Italy
- Correspondence: ; Tel.: +39-0116704660
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Xing Y, Wei X, Wang MM, Liu Y, Sui Z, Wang X, Zhang Y, Fei YH, Jiang Y, Lu C, Zhang P, Chen R, Liu N, Wu M, Ding L, Wang Y, Guo F, Cao JL, Qi J, Wang W. Stimulating TRPM7 suppresses cancer cell proliferation and metastasis by inhibiting autophagy. Cancer Lett 2022; 525:179-197. [PMID: 34752845 DOI: 10.1016/j.canlet.2021.10.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/26/2021] [Accepted: 10/30/2021] [Indexed: 12/15/2022]
Abstract
The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitous cation channel possessing kinase activity. TRPM7 mediates a variety of physiological responses by conducting flow of cations such as Ca2+, Mg2+, and Zn2+. Here, we show that the activation of TRPM7 channel stimulated by chemical agonists of TRPM7, Clozapine or Naltriben, inhibited autophagy via mediating Zn2+ release to the cytosol, presumably from the intracellular Zn2+-accumulating vesicles where TRPM7 localizes. Zn2+ release following the activation of TRPM7 disrupted the fusion between autophagosomes and lysosomes by disturbing the interaction between Sxt17 and VAMP8 which determines fusion status of autophagosomes and lysosomes. Ultimately, the disrupted fusion resulting from stimulation of TRPM7 channels arrested autophagy. Functionally, we demonstrate that the autophagy inhibition mediated by TRPM7 triggered cell death and suppressed metastasis of cancer cells in vitro, more importantly, restricted tumor growth and metastasis in vivo, by evoking apoptosis, cell cycle arrest, and reactive oxygen species (ROS) elevation. These findings represent a strategy for stimulating TRPM7 to combat cancer.
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Affiliation(s)
- Yanhong Xing
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Xiangqing Wei
- Department of Anesthesiology, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu 226006, China
| | - Meng-Meng Wang
- Department of Otolaryngology and Neck Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110122, China
| | - Yucheng Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Zhongheng Sui
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Xinyan Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Yang Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Yuan-Hui Fei
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Yi Jiang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Chen Lu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Peng Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Rong Chen
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Nan Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Mengmei Wu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Lin Ding
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China
| | - Yuqing Wang
- Department of Medicine and Biosystemic Science, Faculty of Medicine, Kyushu University, Fukuoka, Kyusyu 8128582, Japan
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Jun-Li Cao
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China.
| | - Jiansong Qi
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China; Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - Wuyang Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, 209 Tongshan Rd, Xuzhou, Jiangsu 221004, China.
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TRPM7 Ion Channel: Oncogenic Roles and Therapeutic Potential in Breast Cancer. Cancers (Basel) 2021; 13:cancers13246322. [PMID: 34944940 PMCID: PMC8699295 DOI: 10.3390/cancers13246322] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary Breast cancer is the most frequently diagnosed malignant tumor and the second leading cause of cancer death in women worldwide. The risk of developing breast cancer is 12.8%, i.e., 1 in 8 people, and a woman’s risk of dying is approximately 1 in 39. Calcium signals play an important role in various cancers and transport calcium ions may have altered expression in breast cancer, such as the TRPM7 calcium permeant ion channel, where overexpression may be associated with a poor prognosis. This review focuses on the TRPM7 channel, and the oncogenic roles studied so far in breast cancer. The TRPM7 ion channel is suggested as a potential and prospective target in the diagnosis and treatment of breast cancer. Abstract The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a divalent cations permeant channel but also has intrinsic serine/threonine kinase activity. It is ubiquitously expressed in normal tissues and studies have indicated that it participates in important physiological and pharmacological processes through its channel-kinase activity, such as calcium/magnesium homeostasis, phosphorylation of proteins involved in embryogenesis or the cellular process. Accumulating evidence has shown that TRPM7 is overexpressed in human pathologies including breast cancer. Breast cancer is the second leading cause of cancer death in women with an incidence rate increase of around 0.5% per year since 2004. The overexpression of TRPM7 may be associated with a poor prognosis in breast cancer patients, so more efforts are needed to research a new therapeutic target. TRPM7 regulates the levels of Ca2+, which can alter the signaling pathways involved in survival, cell cycle progression, proliferation, growth, migration, invasion, epithelial-mesenchymal transition and thus determines cell behavior, promoting tumor development. This work provides a complete overview of the TRPM7 ion channel and its main involvements in breast cancer. Special consideration is given to the modulation of the channel as a potential target in breast cancer treatment by inhibition of proliferation, migration and invasion. Taken together, these data suggest the potential exploitation of TRPM7 channel-kinase as a therapeutic target and a diagnostic biomarker.
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Characterization of IL-2 Stimulation and TRPM7 Pharmacomodulation in NK Cell Cytotoxicity and Channel Co-Localization with PIP 2 in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182211879. [PMID: 34831634 PMCID: PMC8618557 DOI: 10.3390/ijerph182211879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/30/2021] [Accepted: 11/08/2021] [Indexed: 12/01/2022]
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex multisystemic disorder responsible for significant disability. Although a unifying etiology for ME/CFS is uncertain, impaired natural killer (NK) cell cytotoxicity represents a consistent and measurable feature of this disorder. Research utilizing patient-derived NK cells has implicated dysregulated calcium (Ca2+) signaling, dysfunction of the phosphatidylinositol-4,5-bisphosphate (PIP2)-dependent cation channel, transient receptor potential melastatin (TRPM) 3, as well as altered surface expression patterns of TRPM3 and TRPM2 in the pathophysiology of ME/CFS. TRPM7 is a related channel that is modulated by PIP2 and participates in Ca2+ signaling. Though TRPM7 is expressed on NK cells, the role of TRPM7 with IL-2 and intracellular signaling mechanisms in the NK cells of ME/CFS patients is unknown. This study examined the effect of IL-2 stimulation and TRPM7 pharmacomodulation on NK cell cytotoxicity using flow cytometric assays as well as co-localization of TRPM7 with PIP2 and cortical actin using confocal microscopy in 17 ME/CFS patients and 17 age- and sex-matched healthy controls. The outcomes of this investigation are preliminary and indicate that crosstalk between IL-2 and TRMP7 exists. A larger sample size to confirm these findings and characterization of TRPM7 in ME/CFS using other experimental modalities are warranted.
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Chokshi R, Bennett O, Zhelay T, Kozak JA. NSAIDs Naproxen, Ibuprofen, Salicylate, and Aspirin Inhibit TRPM7 Channels by Cytosolic Acidification. Front Physiol 2021; 12:727549. [PMID: 34733174 PMCID: PMC8558630 DOI: 10.3389/fphys.2021.727549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/10/2021] [Indexed: 01/23/2023] Open
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are used for relieving pain and inflammation accompanying numerous disease states. The primary therapeutic mechanism of these widely used drugs is the inhibition of cyclooxygenase 1 and 2 (COX1, 2) enzymes that catalyze the conversion of arachidonic acid into prostaglandins. At higher doses, NSAIDs are used for prevention of certain types of cancer and as experimental treatments for Alzheimer’s disease. In the immune system, various NSAIDs have been reported to influence neutrophil function and lymphocyte proliferation, and affect ion channels and cellular calcium homeostasis. Transient receptor potential melastatin 7 (TRPM7) cation channels are highly expressed in T lymphocytes and are inhibited by Mg2+, acidic pH, and polyamines. Here, we report a novel effect of naproxen, ibuprofen, salicylate, and acetylsalicylate on TRPM7. At concentrations of 3–30mM, they reversibly inhibited TRPM7 channel currents. By measuring intracellular pH with the ratiometric indicator BCECF, we found that at 300μM to 30mM, these NSAIDs reversibly acidified the cytoplasm in a concentration-dependent manner, and propose that TRPM7 channel inhibition is a consequence of cytosolic acidification, rather than direct. NSAID inhibition of TRPM7 channels was slow, voltage-independent, and displayed use-dependence, increasing in potency upon repeated drug applications. The extent of channel inhibition by salicylate strongly depended on cellular PI(4,5)P2 levels, as revealed when this phospholipid was depleted with voltage-sensitive lipid phosphatase (VSP). Salicylate inhibited heterologously expressed wildtype TRPM7 channels but not the S1107R variant, which is insensitive to cytosolic pH, Mg2+, and PI(4,5)P2 depletion. NSAID-induced acidification was also observed in Schneider 2 cells from Drosophila, an organism that lacks orthologous COX genes, suggesting that this effect is unrelated to COX enzyme activity. A 24-h exposure to 300μM–10mM naproxen resulted in a concentration-dependent reduction in cell viability. In addition to TRPM7, the described NSAID effect would be expected to apply to other ion channels and transporters sensitive to intracellular pH.
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Affiliation(s)
- Rikki Chokshi
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, College of Science and Mathematics, Wright State University, Dayton, OH, United States
| | - Orville Bennett
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, College of Science and Mathematics, Wright State University, Dayton, OH, United States
| | - Tetyana Zhelay
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, College of Science and Mathematics, Wright State University, Dayton, OH, United States
| | - J Ashot Kozak
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, College of Science and Mathematics, Wright State University, Dayton, OH, United States
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Liang HY, Chen Y, Wei X, Ma GG, Ding J, Lu C, Zhou RP, Hu W. Immunomodulatory functions of TRPM7 and its implications in autoimmune diseases. Immunology 2021; 165:3-21. [PMID: 34558663 DOI: 10.1111/imm.13420] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 08/17/2021] [Accepted: 09/14/2021] [Indexed: 12/18/2022] Open
Abstract
An autoimmune disease is an inappropriate response to one's tissues due to a break in immune tolerance and exposure to self-antigens. It often leads to structural and functional damage to organs and systemic disorders. To date, there are no effective interventions to prevent the progression of autoimmune diseases. Hence, there is an urgent need for new treatment targets. TRPM7 is an enzyme-coupled, transient receptor ion channel of the subfamily M that plays a vital role in pathologic and physiologic conditions. While TRPM7 is constitutively activated under certain conditions, it can regulate cell migration, polarization, proliferation and cytokine secretion. However, a growing body of evidence highlights the critical role of TRPM7 in autoimmune diseases, including rheumatoid arthritis, multiple sclerosis and diabetes. Herein, we present (a) a review of the channel kinase properties of TRPM7 and its pharmacological properties, (b) discuss the role of TRPM7 in immune cells (neutrophils, macrophages, lymphocytes and mast cells) and its upstream immunoreactive substances, and (c) highlight TRPM7 as a potential therapeutic target for autoimmune diseases.
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Affiliation(s)
- Hong-Yu Liang
- The Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yong Chen
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
| | - Xin Wei
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
| | - Gang-Gang Ma
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
| | - Jie Ding
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
| | - Chao Lu
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
| | - Ren-Peng Zhou
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China.,The Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China
| | - Wei Hu
- Department of Clinical Pharmacology, The Second Hospital of Anhui Medical University, Hefei, China
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12
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Inoue H, Murayama T, Kobayashi T, Konishi M, Yokoyama U. The zinc-binding motif of TRPM7 acts as an oxidative stress sensor to regulate its channel activity. J Gen Physiol 2021; 153:212116. [PMID: 33999118 PMCID: PMC8129778 DOI: 10.1085/jgp.202012708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 02/02/2021] [Accepted: 04/27/2021] [Indexed: 01/03/2023] Open
Abstract
The activity of the TRPM7 channel is negatively regulated by intracellular Mg2+. We previously reported that oxidative stress enhances the inhibition of TRPM7 by intracellular Mg2+. Here, we aimed to clarify the mechanism underlying TRPM7 inhibition by hydrogen peroxide (H2O2). Site-directed mutagenesis of full-length TRPM7 revealed that none of the cysteines other than C1809 and C1813 within the zinc-binding motif of the TRPM7 kinase domain were involved in the H2O2-induced TRPM7 inhibition. Mutation of C1809 or C1813 prevented expression of full-length TRPM7 on the plasma membrane. We therefore developed an assay to functionally reconstitute full-length TRPM7 by coexpressing the TRPM7 channel domain (M7cd) and the TRPM7 kinase domain (M7kd) as separate proteins in HEK293 cells. When M7cd was expressed alone, the current was inhibited by intracellular Mg2+ more strongly than that of full-length TRPM7 and was insensitive to oxidative stress. Coexpression of M7cd and M7kd attenuated the inhibition by intracellular Mg2+ and restored sensitivity to oxidative stress, indicating successful reconstitution of a full-length TRPM7-like current. We observed a similar effect when M7cd was coexpressed with the kinase-inactive mutant M7kd-K1645R, suggesting that the kinase activity is not essential for the reconstitution. However, coexpression of M7cd and M7kd carrying a mutation at either C1809 or C1813 failed to restore the full-length TRPM7-like current. No reconstitution was observed when using M7kd carrying a mutation at H1750 and H1807, which are involved in the zinc-binding motif formation with C1809 and C1813. These data suggest that the zinc-binding motif is essential for the intracellular Mg2+-dependent regulation of the TRPM7 channel activity by its kinase domain and that the cysteines in the zinc-binding motif play a role in the oxidative stress response of TRPM7.
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Affiliation(s)
- Hana Inoue
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takuya Kobayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masato Konishi
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Utako Yokoyama
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
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13
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TRPM7-Mediated Calcium Transport in HAT-7 Ameloblasts. Int J Mol Sci 2021; 22:ijms22083992. [PMID: 33924361 PMCID: PMC8069123 DOI: 10.3390/ijms22083992] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023] Open
Abstract
TRPM7 plays an important role in cellular Ca2+, Zn2+ and Mg2+ homeostasis. TRPM7 channels are abundantly expressed in ameloblasts and, in the absence of TRPM7, dental enamel is hypomineralized. The potential role of TRPM7 channels in Ca2+ transport during amelogenesis was investigated in the HAT-7 rat ameloblast cell line. The cells showed strong TRPM7 mRNA and protein expression. Characteristic TRPM7 transmembrane currents were observed, which increased in the absence of intracellular Mg2+ ([Mg2+]i), were reduced by elevated [Mg2+]i, and were inhibited by the TRPM7 inhibitors NS8593 and FTY720. Mibefradil evoked similar currents, which were suppressed by elevated [Mg2+]i, reducing extracellular pH stimulated transmembrane currents, which were inhibited by FTY720. Naltriben and mibefradil both evoked Ca2+ influx, which was further enhanced by the acidic intracellular conditions. The SOCE inhibitor BTP2 blocked Ca2+ entry induced by naltriben but not by mibefradil. Thus, in HAT-7 cells, TRPM7 may serves both as a potential modulator of Orai-dependent Ca2+ uptake and as an independent Ca2+ entry pathway sensitive to pH. Therefore, TRPM7 may contribute directly to transepithelial Ca2+ transport in amelogenesis.
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14
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Beesetty P, Rockwood J, Kaitsuka T, Zhelay T, Hourani S, Matsushita M, Kozak JA. Phagocytic activity of splenic macrophages is enhanced and accompanied by cytosolic alkalinization in TRPM7 kinase-dead mice. FEBS J 2021; 288:3585-3601. [PMID: 33354894 DOI: 10.1111/febs.15683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/29/2020] [Accepted: 12/21/2020] [Indexed: 12/31/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a unique protein functioning as a cation channel as well as a serine/threonine kinase and is highly expressed in immune cells such as lymphocytes and macrophages. TRPM7 kinase-dead (KD) mouse model has been used to investigate the role of this protein in immune cells; these animals display moderate splenomegaly and ectopic hemopoiesis. The basal TRPM7 current magnitudes in peritoneal macrophages isolated from KD mice were higher; however, the maximum currents, achieved after cytoplasmic Mg2+ washout, were not different. In the present study, we investigated the consequences of TRPM7 kinase inactivation in splenic and peritoneal macrophages. We measured the basal phagocytic activity of splenic macrophages using fluorescent latex beads, pHrodo zymosan bioparticles, and opsonized red blood cells. KD macrophages phagocytized more efficiently and had slightly higher baseline calcium levels compared to WT cells. We found no obvious differences in store-operated Ca2+ entry between WT and KD macrophages. By contrast, the resting cytosolic pH in KD macrophages was significantly more alkaline than in WT. Pharmacological blockade of sodium hydrogen exchanger 1 (NHE1) reversed the cytosolic alkalinization and reduced phagocytosis in KD macrophages. Basal TRPM7 channel activity in KD macrophages was also reduced after NHE1 blockade. Cytosolic Mg2+ sensitivity of TRPM7 channels measured in peritoneal macrophages was similar in WT and KD mice. The higher basal TRPM7 channel activity in KD macrophages is likely due to alkalinization. Our results identify a novel role for TRPM7 kinase as a suppressor of basal phagocytosis and a regulator of cellular pH.
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Affiliation(s)
- Pavani Beesetty
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, USA
| | - Jananie Rockwood
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, USA
| | - Taku Kaitsuka
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Japan
| | - Tetyana Zhelay
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, USA
| | - Siham Hourani
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, USA
| | - Masayuki Matsushita
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - J Ashot Kozak
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, USA
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15
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Jimenez I, Prado Y, Marchant F, Otero C, Eltit F, Cabello-Verrugio C, Cerda O, Simon F. TRPM Channels in Human Diseases. Cells 2020; 9:E2604. [PMID: 33291725 PMCID: PMC7761947 DOI: 10.3390/cells9122604] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
The transient receptor potential melastatin (TRPM) subfamily belongs to the TRP cation channels family. Since the first cloning of TRPM1 in 1989, tremendous progress has been made in identifying novel members of the TRPM subfamily and their functions. The TRPM subfamily is composed of eight members consisting of four six-transmembrane domain subunits, resulting in homomeric or heteromeric channels. From a structural point of view, based on the homology sequence of the coiled-coil in the C-terminus, the eight TRPM members are clustered into four groups: TRPM1/M3, M2/M8, M4/M5 and M6/M7. TRPM subfamily members have been involved in several physiological functions. However, they are also linked to diverse pathophysiological human processes. Alterations in the expression and function of TRPM subfamily ion channels might generate several human diseases including cardiovascular and neurodegenerative alterations, organ dysfunction, cancer and many other channelopathies. These effects position them as remarkable putative targets for novel diagnostic strategies, drug design and therapeutic approaches. Here, we review the current knowledge about the main characteristics of all members of the TRPM family, focusing on their actions in human diseases.
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Affiliation(s)
- Ivanka Jimenez
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Yolanda Prado
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Felipe Marchant
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Carolina Otero
- Faculty of Medicine, School of Chemistry and Pharmacy, Universidad Andrés Bello, Santiago 8370186, Chile;
| | - Felipe Eltit
- Vancouver Prostate Centre, Vancouver, BC V6Z 1Y6, Canada;
- Department of Urological Sciences, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada
| | - Claudio Cabello-Verrugio
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago 7560484, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8370146, Chile
| | - Oscar Cerda
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
| | - Felipe Simon
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
- Millennium Institute on Immunology and Immunotherapy, Santiago 8370146, Chile
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16
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Liu M, Dudley SC. Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease. Antioxidants (Basel) 2020; 9:E907. [PMID: 32977544 PMCID: PMC7598282 DOI: 10.3390/antiox9100907] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022] Open
Abstract
Hypomagnesemia is commonly observed in heart failure, diabetes mellitus, hypertension, and cardiovascular diseases. Low serum magnesium (Mg) is a predictor for cardiovascular and all-cause mortality and treating Mg deficiency may help prevent cardiovascular disease. In this review, we discuss the possible mechanisms by which Mg deficiency plays detrimental roles in cardiovascular diseases and review the results of clinical trials of Mg supplementation for heart failure, arrhythmias and other cardiovascular diseases.
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Affiliation(s)
- Man Liu
- Division of Cardiology, Department of Medicine, the Lillehei Heart Institute, University of Minnesota at Twin Cities, Minneapolis, MN 55455, USA
| | - Samuel C. Dudley
- Division of Cardiology, Department of Medicine, the Lillehei Heart Institute, University of Minnesota at Twin Cities, Minneapolis, MN 55455, USA
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17
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Mellott A, Rockwood J, Zhelay T, Luu CT, Kaitsuka T, Kozak JA. TRPM7 channel activity in Jurkat T lymphocytes during magnesium depletion and loading: implications for divalent metal entry and cytotoxicity. Pflugers Arch 2020; 472:1589-1606. [PMID: 32964285 DOI: 10.1007/s00424-020-02457-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/14/2022]
Abstract
TRPM7 is a cation channel-protein kinase highly expressed in T lymphocytes and other immune cells. It has been proposed to constitute a cellular entry pathway for Mg2+ and divalent metal cations such as Ca2+, Zn2+, Cd2+, Mn2+, and Ni2+. TRPM7 channels are inhibited by cytosolic Mg2+, rendering them largely inactive in intact cells. The dependence of channel activity on extracellular Mg2+ is less well studied. Here, we measured native TRPM7 channel activity in Jurkat T cells maintained in external Mg2+ concentrations varying between 400 nM and 1.4 mM for 1-3 days, obtaining an IC50 value of 54 μM. Maintaining the cells in 400 nM or 8 μM [Mg2+]o resulted in almost complete activation of TRPM7 in intact cells, due to cytosolic Mg2+ depletion. A total of 1.4 mM [Mg2+]o was sufficient to fully eliminate the basal current. Submillimolar concentrations of amiloride prevented cellular Mg2+ depletion but not loading. We investigated whether the cytotoxicity of TRPM7 permeant metal ions Ni2+, Zn2+, Cd2+, Co2+, Mn2+, Sr2+, and Ba2+ requires TRPM7 channel activity. Mg2+ loading modestly reduced cytotoxicity of Zn2+, Co2+, Ni2+, and Mn2+ but not of Cd2+. Channel blocker NS8593 reduced Co2+ and Mn2+ but not Cd2+ or Zn2+ cytotoxicity and interfered with Mg2+ loading as evaluated by TRPM7 channel basal activity. Ba2+ and Sr2+ were neither detectably toxic nor permeant through the plasma membrane. These results indicate that in Jurkat T cells, entry of toxic divalent metal cations primarily occurs through pathways distinct from TRPM7. By contrast, we found evidence that Mg2+ entry requires TRPM7 channels.
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Affiliation(s)
- Alayna Mellott
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Jananie Rockwood
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Tetyana Zhelay
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Charles Tuan Luu
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Taku Kaitsuka
- School of Pharmacy in Fukuoka, International University of Health and Welfare, Enokizu 137-1, Okawa, Fukuoka, Japan
| | - J Ashot Kozak
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA.
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18
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Pethő Z, Najder K, Carvalho T, McMorrow R, Todesca LM, Rugi M, Bulk E, Chan A, Löwik CWGM, Reshkin SJ, Schwab A. pH-Channeling in Cancer: How pH-Dependence of Cation Channels Shapes Cancer Pathophysiology. Cancers (Basel) 2020; 12:E2484. [PMID: 32887220 PMCID: PMC7565548 DOI: 10.3390/cancers12092484] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022] Open
Abstract
Tissue acidosis plays a pivotal role in tumor progression: in particular, interstitial acidosis promotes tumor cell invasion, and is a major contributor to the dysregulation of tumor immunity and tumor stromal cells. The cell membrane and integral membrane proteins commonly act as important sensors and transducers of altered pH. Cell adhesion molecules and cation channels are prominent membrane proteins, the majority of which is regulated by protons. The pathophysiological consequences of proton-sensitive ion channel function in cancer, however, are scarcely considered in the literature. Thus, the main focus of this review is to highlight possible events in tumor progression and tumor immunity where the pH sensitivity of cation channels could be of great importance.
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Affiliation(s)
- Zoltán Pethő
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Karolina Najder
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Tiago Carvalho
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Roisin McMorrow
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
| | - Luca Matteo Todesca
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Micol Rugi
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Etmar Bulk
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
| | - Alan Chan
- Percuros B.V., 2333 CL Leiden, The Netherlands;
| | - Clemens W. G. M. Löwik
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, 3035 GD Rotterdam, The Netherlands; (R.M.); (C.W.G.M.L.)
- Department of Oncology CHUV, UNIL and Ludwig Cancer Center, 1011 Lausanne, Switzerland
| | - Stephan J. Reshkin
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 90126 Bari, Italy; (T.C.); (S.J.R.)
| | - Albrecht Schwab
- Institute of Physiology II, University Münster, 48147 Münster, Germany; (K.N.); (L.M.T.); (M.R.); (E.B.); (A.S.)
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19
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Inoue H, Inazu M, Konishi M, Yokoyama U. Functional expression of TRPM7 as a Ca 2+ influx pathway in adipocytes. Physiol Rep 2020; 7:e14272. [PMID: 31650715 PMCID: PMC6813326 DOI: 10.14814/phy2.14272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 09/20/2019] [Accepted: 10/04/2019] [Indexed: 02/01/2023] Open
Abstract
In adipocytes, intracellular Ca2+ and Mg2+ modulates physiological functions, such as insulin action and the secretion of adipokines. TRPM7 is a Ca2+/Mg2+‐permeable non‐selective cation channel. TRPM7 mRNA is highly expressed in adipose tissue, however, its functional expression in adipocytes remains to be elucidated. In this study, we demonstrated for the first time that TRPM7 was functionally expressed in both freshly isolated white adipocytes and in 3T3‐L1 adipocytes differentiated from a 3T3‐L1 pre‐adipocyte cell line by whole‐cell patch‐clamp recordings. Consistent with known properties of TRPM7 current, the current in adipocytes was activated by the elimination of extracellular divalent cations and the reduction of intracellular free Mg2+ concentrations, and was inhibited by the TRPM7 inhibitors, 2‐aminoethyl diphenylborinate (2‐APB), hydrogen peroxide (H2O2), N‐methyl maleimide (NMM), NS8593, and 2‐amino‐2‐[2‐(4‐octylphenyl)ethyl]‐1,3‐propanediol (FTY720). Treatment with small‐interfering (si) RNA targeting TRPM7 resulted in a reduction in the current to 23 ± 7% of nontargeting siRNA‐treated adipocytes. Moreover a TRPM7 activator, naltriben, increased the TRPM7‐like current and [Ca2+]i in 3T3‐L1 adipocytes but not in TRPM7‐knockdown adipocytes. These findings indicate that TRPM7 is functionally expressed, and plays a role as a Ca2+ influx pathway in adipocytes.
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Affiliation(s)
- Hana Inoue
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Masato Inazu
- Institute of Medical Science, Tokyo Medical University, Tokyo, Japan
| | - Masato Konishi
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Utako Yokoyama
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
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20
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Wan J, Li J, Bandyopadhyay S, Kelly SL, Xiang Y, Zhang J, Merrill AH, Duan J. Analysis of 1-Deoxysphingoid Bases and Their N-Acyl Metabolites and Exploration of Their Occurrence in Some Food Materials. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:12953-12961. [PMID: 31638789 DOI: 10.1021/acs.jafc.9b05708] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Most common sphingolipids are comprised of "typical" sphingoid bases (sphinganine, sphingosine, and structurally related compounds) and are produced via the condensation of l-serine with a fatty acyl-CoA by serine palmitoyltransferase. Some organisms, including mammals, also produce "atypical" sphingoid bases that lack a 1-hydroxyl group as a result of the utilization of l-alanine or glycine instead of l-serine, resulting in the formation of 1-deoxy- or 1-desoxymethylsphingoid bases, respectively. Elevated production of "atypical" sphingolipids has been associated with human disease, but 1-deoxysphingoid bases have also been found to have potential as anticancer compounds, hence, the importance of knowing more about the occurrence of these compounds in food. Most of the "typical" and "atypical" sphingoid bases are found as the N-acyl metabolites (e.g., ceramides and 1-deoxyceramides) in mammals, but this has not been uniformly assessed in previous studies nor determined in consumed food. Therefore, we developed a method for the quantitative analysis of "typical" and "atypical" sphingoid bases and their N-acyl derivatives by reverse-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. On the basis of these analyses, there was considerable variability in the amounts and molecular subspecies of atypical sphingoid bases and their N-acyl metabolites found in different edible sources. These findings demonstrate that a broader assessment of the types of sphingolipids in foods is needed because some diets might contain sufficient amounts of atypical as well as typical sphingolipids that could have beneficial or possibly deleterious effects on human health.
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Affiliation(s)
| | - Jian Li
- College of Pharmaceutical Sciences , Ganan Medical University , Ganzhou , Jiangxi 341000 , People's Republic of China
| | - Sibali Bandyopadhyay
- Schools of Biological Sciences and the Parker H. Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Samuel L Kelly
- Schools of Biological Sciences and the Parker H. Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | | | | | - Alfred H Merrill
- Schools of Biological Sciences and the Parker H. Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Jingjing Duan
- Schools of Biological Sciences and the Parker H. Petit Institute for Bioengineering and Bioscience , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
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21
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Zhelay T, Wieczerzak KB, Beesetty P, Alter GM, Matsushita M, Kozak JA. Depletion of plasma membrane-associated phosphoinositides mimics inhibition of TRPM7 channels by cytosolic Mg 2+, spermine, and pH. J Biol Chem 2018; 293:18151-18167. [PMID: 30305398 PMCID: PMC6254349 DOI: 10.1074/jbc.ra118.004066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/04/2018] [Indexed: 12/20/2022] Open
Abstract
Transient receptor potential cation channel subfamily M member 7 (TRPM7) is an ion channel/protein kinase belonging to the TRP melastatin and eEF2 kinase families. Under physiological conditions, most native TRPM7 channels are inhibited by cytoplasmic Mg2+, protons, and polyamines. Currents through these channels (ITRPM7) are robustly potentiated when the cell interior is exchanged with low Mg2+-containing buffers. ITRPM7 is also potentiated by phosphatidyl inositol bisphosphate (PI(4,5)P2) and suppressed by its hydrolysis. Here we characterized internal Mg2+- and pH-mediated inhibition of TRPM7 channels in HEK293 cells overexpressing WT voltage-sensing phospholipid phosphatase (VSP) or its catalytically inactive variant VSP-C363S. VSP-mediated depletion of membrane phosphoinositides significantly increased channel sensitivity to Mg2+ and pH. Proton concentrations that were too low to inhibit ITRPM7 when the VSP-C363S variant was expressed (pH 8.2) became inhibitory in WT VSP-expressing cells. At pH 6.5, protons inhibited ITRPM7 both in WT and VSP C363S-expressing cells but with a faster time course in the WT VSP-expressing cells. Inhibition by 150 μm Mg2+ was also significantly faster in the WT VSP-expressing cells. Cellular PI(4,5)P2 depletion increased the sensitivity of TRPM7 channels to the inhibitor 2-aminoethyl diphenyl borinate, which acidifies the cytosol. Single substitutions at Ser-1107 of TRPM7, reducing its sensitivity to Mg2+, also decreased its inhibition by spermine and acidic pH. Furthermore, these channel variants were markedly less sensitive to VSP-mediated PI(4,5)P2 depletion than the WT. We conclude that the internal Mg2+-, polyamine-, and pH-mediated inhibition of TRPM7 channels is not direct but, rather, reflects electrostatic screening and resultant disruption of PI(4,5)P2-channel interactions.
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Affiliation(s)
- Tetyana Zhelay
- From the Departments of Neuroscience, Cell Biology, and Physiology and
| | | | - Pavani Beesetty
- From the Departments of Neuroscience, Cell Biology, and Physiology and
| | - Gerald M Alter
- Biochemistry and Molecular Biology, Wright State University, Dayton, Ohio 45435 and
| | - Masayuki Matsushita
- the Department of Molecular and Cellular Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - J Ashot Kozak
- From the Departments of Neuroscience, Cell Biology, and Physiology and.
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22
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Structure of the mammalian TRPM7, a magnesium channel required during embryonic development. Proc Natl Acad Sci U S A 2018; 115:E8201-E8210. [PMID: 30108148 PMCID: PMC6126765 DOI: 10.1073/pnas.1810719115] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The transient receptor potential ion channel subfamily M, member 7 (TRPM7), is a ubiquitously expressed protein that is required for mouse embryonic development. TRPM7 contains both an ion channel and an α-kinase. The channel domain comprises a nonselective cation channel with notable permeability to Mg2+ and Zn2+ Here, we report the closed state structures of the mouse TRPM7 channel domain in three different ionic conditions to overall resolutions of 3.3, 3.7, and 4.1 Å. The structures reveal key residues for an ion binding site in the selectivity filter, with proposed partially hydrated Mg2+ ions occupying the center of the conduction pore. In high [Mg2+], a prominent external disulfide bond is found in the pore helix, which is essential for ion channel function. Our results provide a structural framework for understanding the TRPM1/3/6/7 subfamily and extend the knowledge base upon which to study the diversity and evolution of TRP channels.
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23
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Fels B, Bulk E, Pethő Z, Schwab A. The Role of TRP Channels in the Metastatic Cascade. Pharmaceuticals (Basel) 2018; 11:E48. [PMID: 29772843 PMCID: PMC6027473 DOI: 10.3390/ph11020048] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/16/2022] Open
Abstract
A dysregulated cellular Ca2+ homeostasis is involved in multiple pathologies including cancer. Changes in Ca2+ signaling caused by altered fluxes through ion channels and transporters (the transportome) are involved in all steps of the metastatic cascade. Cancer cells thereby "re-program" and "misuse" the cellular transportome to regulate proliferation, apoptosis, metabolism, growth factor signaling, migration and invasion. Cancer cells use their transportome to cope with diverse environmental challenges during the metastatic cascade, like hypoxic, acidic and mechanical cues. Hence, ion channels and transporters are key modulators of cancer progression. This review focuses on the role of transient receptor potential (TRP) channels in the metastatic cascade. After briefly introducing the role of the transportome in cancer, we discuss TRP channel functions in cancer cell migration. We highlight the role of TRP channels in sensing and transmitting cues from the tumor microenvironment and discuss their role in cancer cell invasion. We identify open questions concerning the role of TRP channels in circulating tumor cells and in the processes of intra- and extravasation of tumor cells. We emphasize the importance of TRP channels in different steps of cancer metastasis and propose cancer-specific TRP channel blockade as a therapeutic option in cancer treatment.
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Affiliation(s)
- Benedikt Fels
- Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany.
| | - Etmar Bulk
- Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany.
| | - Zoltán Pethő
- Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany.
| | - Albrecht Schwab
- Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany.
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24
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Rimkute L, Kraujalis T, Snipas M, Palacios-Prado N, Jotautis V, Skeberdis VA, Bukauskas FF. Modulation of Connexin-36 Gap Junction Channels by Intracellular pH and Magnesium Ions. Front Physiol 2018; 9:362. [PMID: 29706896 PMCID: PMC5906587 DOI: 10.3389/fphys.2018.00362] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/23/2018] [Indexed: 11/13/2022] Open
Abstract
Connexin-36 (Cx36) protein forms gap junction (GJ) channels in pancreatic beta cells and is also the main Cx isoform forming electrical synapses in the adult mammalian brain. Cx36 GJs can be regulated by intracellular pH (pHi) and cytosolic magnesium ion concentration ([Mg2+]i), which can vary significantly under various physiological and pathological conditions. However, the combined effect and relationship of these two factors over Cx36-dependent coupling have not been previously studied in detail. Our experimental results in HeLa cells expressing Cx36 show that changes in both pHi and [Mg2+]i affect junctional conductance (gj) in an interdependent manner; in other words, intracellular acidification cause increase or decay in gj depending on whether [Mg2+]i is high or low, respectively, and intracellular alkalization cause reduction in gj independently of [Mg2+]i. Our experimental and modelling data support the hypothesis that Cx36 GJ channels contain two separate gating mechanisms, and both are differentially sensitive to changes in pHi and [Mg2+]i. Using recombinant Cx36 we found that two glutamate residues in the N-terminus could be partly responsible for the observed interrelated effect of pHi and [Mg2+]i. Mutation of glutamate at position 8 attenuated the stimulatory effect of intracellular acidification at high [Mg2+]i, while mutation at position 12 and double mutation at both positions reversed stimulatory effect to inhibition. Moreover, Cx36*E8Q lost the initial increase of gj at low [Mg2+]i and double mutation lost the sensitivity to high [Mg2+]i. These results suggest that E8 and E12 are involved in regulation of Cx36 GJ channels by Mg2+ and H+ ions.
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Affiliation(s)
- Lina Rimkute
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Tadas Kraujalis
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
- Department of Applied Informatics, Kaunas University of Technology, Kaunas, Lithuania
| | - Mindaugas Snipas
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
- Department of Mathematical Modelling, Kaunas University of Technology, Kaunas, Lithuania
| | - Nicolas Palacios-Prado
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Vaidas Jotautis
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Vytenis A. Skeberdis
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
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25
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Inactivation of TRPM7 kinase in mice results in enlarged spleens, reduced T-cell proliferation and diminished store-operated calcium entry. Sci Rep 2018; 8:3023. [PMID: 29445164 PMCID: PMC5813043 DOI: 10.1038/s41598-018-21004-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/29/2018] [Indexed: 12/20/2022] Open
Abstract
T lymphocytes enlarge (blast) and proliferate in response to antigens in a multistep program that involves obligatory cytosolic calcium elevations. Store-operated calcium entry (SOCE) pathway is the primary source of Ca2+ in these cells. Here, we describe a novel modulator of blastogenesis, proliferation and SOCE: the TRPM7 channel kinase. TRPM7 kinase-dead (KD) K1646R knock-in mice exhibited splenomegaly and impaired blastogenic responses elicited by PMA/ionomycin or anti-CD3/CD28 antibodies. Splenic T-cell proliferation in vitro was weaker in the mutant compared to wildtype littermates. TRPM7 current magnitudes in WT and KD mouse T cells were, however, similar. We tested the dependence of T-cell proliferation on external Ca2+ and Mg2+ concentrations. At a fixed [Mg2+o] of ~0.4 mM, Ca2+o stimulated proliferation with a steep concentration dependence and vice versa, at a fixed [Ca2+o] of ~0.4 mM, Mg2+o positively regulated proliferation but with a shallower dependence. Proliferation was significantly lower in KD mouse than in wildtype at all Ca2+ and Mg2+ concentrations. Ca2+ elevations elicited by anti-CD3 antibody were diminished in KD mutant T cells and SOCE measured in activated KD splenocytes was reduced. These results demonstrate that a functional TRPM7 kinase supports robust SOCE, blastogenesis and proliferation, whereas its inactivation suppresses these cellular events.
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26
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Sisquella X, Nebl T, Thompson JK, Whitehead L, Malpede BM, Salinas ND, Rogers K, Tolia NH, Fleig A, O'Neill J, Tham WH, David Horgen F, Cowman AF. Plasmodium falciparum ligand binding to erythrocytes induce alterations in deformability essential for invasion. eLife 2017; 6. [PMID: 28226242 PMCID: PMC5333951 DOI: 10.7554/elife.21083] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/09/2017] [Indexed: 12/31/2022] Open
Abstract
The most lethal form of malaria in humans is caused by Plasmodium falciparum. These parasites invade erythrocytes, a complex process involving multiple ligand-receptor interactions. The parasite makes initial contact with the erythrocyte followed by dramatic deformations linked to the function of the Erythrocyte binding antigen family and P. falciparum reticulocyte binding-like families. We show EBA-175 mediates substantial changes in the deformability of erythrocytes by binding to glycophorin A and activating a phosphorylation cascade that includes erythrocyte cytoskeletal proteins resulting in changes in the viscoelastic properties of the host cell. TRPM7 kinase inhibitors FTY720 and waixenicin A block the changes in the deformability of erythrocytes and inhibit merozoite invasion by directly inhibiting the phosphorylation cascade. Therefore, binding of P. falciparum parasites to the erythrocyte directly activate a signaling pathway through a phosphorylation cascade and this alters the viscoelastic properties of the host membrane conditioning it for successful invasion.
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Affiliation(s)
- Xavier Sisquella
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Thomas Nebl
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Jennifer K Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Lachlan Whitehead
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Brian M Malpede
- Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, St. Louis, United States.,Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Nichole D Salinas
- Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, St. Louis, United States.,Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Kelly Rogers
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Niraj H Tolia
- Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, St. Louis, United States.,Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Andrea Fleig
- The Queen's Medical Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, United States
| | - Joseph O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - F David Horgen
- Department of Natural Sciences, Hawaii Pacific University, Kaneohe, United States
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
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27
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Modulation of Human Cardiac TRPM7 Current by Extracellular Acidic pH Depends upon Extracellular Concentrations of Divalent Cations. PLoS One 2017; 12:e0170923. [PMID: 28129376 PMCID: PMC5271359 DOI: 10.1371/journal.pone.0170923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/12/2017] [Indexed: 11/19/2022] Open
Abstract
TRPM7 channels participate in a variety of physiological/pathological processes. TRPM7 currents are modulated by protons but opposing effects of external pH (pHo) (potentiation vs inhibition) have been reported. TRPM7 has been less studied in human cardiomyocytes than in heart-derived non-cardiomyocyte cells. We used the whole-cell patch-clamp technique on isolated human atrial cardiomyocytes to investigate the impact of an acidic pHo on the TRPM7 current. With voltage-dependent and other ion channels inhibited, cardiomyocytes were challenged with external acidification in either the presence or the absence of extracellular divalent cations. TRPM7 outward and inward currents were increased by acidic pHo in extracellular medium containing Ca2+ and Mg2+, but suppressed by acidic pHo in the absence of extracellular Ca2+ and Mg2+. The potentiating effect in the presence of extracellular divalents occurred at pHo below 6 and was voltage-dependent. The inhibitory effect in the absence of extracellular divalents was already marked at pHo of 6 and was practically voltage-independent. TRPM7 current density was higher in cardiomyocytes from patients with history of coronary vascular disease and the difference compared to cardiomyocytes from patients without history of myocardial ischemia increased with acidic pHo. We demonstrate that proton-induced modification of TRPM7 currents depends on the presence of extracellular Ca2+ and Mg2+. Variability of the TRPM7 current density in human cardiomyocytes is related to the clinical history, being higher in atrial fibrillation and in ischemic cardiomyopathy.
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28
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Jansen C, Sahni J, Suzuki S, Horgen FD, Penner R, Fleig A. The coiled-coil domain of zebrafish TRPM7 regulates Mg·nucleotide sensitivity. Sci Rep 2016; 6:33459. [PMID: 27628598 PMCID: PMC5024298 DOI: 10.1038/srep33459] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/19/2016] [Indexed: 01/15/2023] Open
Abstract
TRPM7 is a member of the Transient-Receptor-Potential Melastatin ion channel family. TRPM7 is a unique fusion protein of an ion channel and an α-kinase. Although mammalian TRPM7 is well characterized biophysically and its pivotal role in cancer, ischemia and cardiovascular disease is becoming increasingly evident, the study of TRPM7 in mouse models has been hampered by embryonic lethality of transgenic ablations. In zebrafish, functional loss of TRPM7 (drTRPM7) manifests itself in an array of non-lethal physiological malfunctions. Here, we investigate the regulation of wild type drTRPM7 and multiple C-terminal truncation mutants. We find that the biophysical properties of drTRPM7 are very similar to mammalian TRPM7. However, pharmacological profiling reveals that drTRPM7 is facilitated rather than inhibited by 2-APB, and that the TRPM7 inhibitor waixenicin A has no effect. This is reminiscent of the pharmacological profile of human TRPM6, the sister channel kinase of TRPM7. Furthermore, using truncation mutations, we show that the coiled-coil domain of drTRPM7 is involved in the channel's regulation by magnesium (Mg) and Mg·adenosine triphosphate (Mg·ATP). We propose that drTRPM7 has two protein domains that regulate inhibition by intracellular magnesium and nucleotides, and one domain that is concerned with sensing magnesium only.
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Affiliation(s)
- Chad Jansen
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
| | - Jaya Sahni
- Center for Immunity and Immunotherapies, Seattle Children’s Research Institute, 1900 9th Ave, Seattle, WA 98101, USA
| | - Sayuri Suzuki
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
| | - F. David Horgen
- Laboratory of Marine Biological Chemistry, Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI 96744, USA
| | - Reinhold Penner
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
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29
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Huguet F, Calvez ML, Benz N, Le Hir S, Mignen O, Buscaglia P, Horgen FD, Férec C, Kerbiriou M, Trouvé P. Function and regulation of TRPM7, as well as intracellular magnesium content, are altered in cells expressing ΔF508-CFTR and G551D-CFTR. Cell Mol Life Sci 2016; 73:3351-73. [PMID: 26874684 PMCID: PMC11108291 DOI: 10.1007/s00018-016-2149-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 01/14/2016] [Accepted: 01/25/2016] [Indexed: 02/03/2023]
Abstract
Cystic fibrosis (CF), one of the most common fatal hereditary disorders, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR gene product is a multidomain adenosine triphosphate-binding cassette (ABC) protein that functions as a chloride (Cl(-)) channel that is regulated by intracellular magnesium [Mg(2+)]i. The most common mutations in CFTR are a deletion of a phenylalanine residue at position 508 (ΔF508-CFTR, 70-80 % of CF phenotypes) and a Gly551Asp substitution (G551D-CFTR, 4-5 % of alleles), which lead to decreased or almost abolished Cl(-) channel function, respectively. Magnesium ions have to be finely regulated within cells for optimal expression and function of CFTR. Therefore, the melastatin-like transient receptor potential cation channel, subfamily M, member 7 (TRPM7), which is responsible for Mg(2+) entry, was studies and [Mg(2+)]i measured in cells stably expressing wildtype CFTR, and two mutant proteins (ΔF508-CFTR and G551D-CFTR). This study shows for the first time that [Mg(2+)]i is decreased in cells expressing ΔF508-CFTR and G551D-CFTR mutated proteins. It was also observed that the expression of the TRPM7 protein is increased; however, membrane localization was altered for both ΔF508del-CFTR and G551D-CFTR. Furthermore, both the function and regulation of the TRPM7 channel regarding Mg(2+) is decreased in the cells expressing the mutated CFTR. Ca(2+) influx via TRPM7 were also modified in cells expressing a mutated CFTR. Therefore, there appears to be a direct involvement of TRPM7 in CF physiopathology. Finally, we propose that the TRPM7 activator Naltriben is a new potentiator for G551D-CFTR as the function of this mutant increases upon activation of TRPM7 by Naltriben.
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Affiliation(s)
- F Huguet
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - M L Calvez
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
- Association G. Saleun, Brest, 29218, France
| | - N Benz
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Association G. Saleun, Brest, 29218, France
| | - S Le Hir
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Laboratoire de Génétique Moléculaire, Hôpital Morvan, C.H.U. Brest, Brest, 29200, France
| | - O Mignen
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - P Buscaglia
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - F D Horgen
- Laboratory of Marine Biological Chemistry, Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - C Férec
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France.
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France.
- Laboratoire de Génétique Moléculaire, Hôpital Morvan, C.H.U. Brest, Brest, 29200, France.
- Etablissement Français du Sang - Bretagne, Brest, 29200, France.
| | - M Kerbiriou
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - P Trouvé
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France.
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30
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Ehling P, Meuth P, Eichinger P, Herrmann AM, Bittner S, Pawlowski M, Pankratz S, Herty M, Budde T, Meuth SG. Human T cells in silico: Modelling their electrophysiological behaviour in health and disease. J Theor Biol 2016; 404:236-250. [PMID: 27288542 DOI: 10.1016/j.jtbi.2016.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/27/2016] [Accepted: 06/01/2016] [Indexed: 01/27/2023]
Abstract
Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simulating the electrophysiological behaviour of resting and activated human CD4(+) T cells under basal conditions and during extracellular acidification. The latter allows for the very first time to assess the electrophysiological consequences of tissue acidosis accompanying most forms of inflammation.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany.
| | - Patrick Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Paul Eichinger
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Alexander M Herrmann
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Matthias Pawlowski
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Wellcome Trust and MRC Cambridge Stem Cell Institute, and Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge, West Forvie Building, Forvie Site, Robinson Way, Cambridge, UK
| | - Susann Pankratz
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Michael Herty
- RWTH Aachen University, Mathematics (Continuous optimization), Templergraben 55, 52056 Aachen, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
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31
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Regulation of TRPM7 Function by IL-6 through the JAK2-STAT3 Signaling Pathway. PLoS One 2016; 11:e0152120. [PMID: 27010689 PMCID: PMC4806911 DOI: 10.1371/journal.pone.0152120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 03/09/2016] [Indexed: 12/25/2022] Open
Abstract
Aims Previous studies have demonstrated that expression of the TRPM7 channel, which may induce delayed cell death by mediating calcium influx, is precisely regulated. However, functional regulation of TRPM7 channels by endogenous molecules has not been elucidated. The proinflammatory cytokine IL-6 contributes to regulation of Ca2+ influx in cerebral ischemia, but the role of IL-6 in regulating TRPM7 functioning is unknown. Thus, we here investigated the interaction between IL-6 and TRPM7 channels and the relevant mechanisms. Materials and Methods Using whole-cell patch-clamping, we first investigated the effect of IL-6 on TRPM7-like currents in primary cultured cortical neurons. Next, TRPM7-overexpressing HEK293 cells were used to confirm the effect of IL-6/sIL-6R on TRPM7. Finally, we used specific signaling pathway inhibitors to investigate the signaling pathways involved. Results IL-6 or IL-6/sIL-6R dose-dependently inhibited inward TRPM7 currents, in both primary cultured neurons and HEK293 cells overexpressing TRPM7. In intracellular Mg2+-free conditions, extracellular Ca2+ or the α-kinase domain of TRPM7 did not participate in this regulation. The inhibitory effect of IL-6 on TRPM7 could be blocked by specific inhibitors of the JAK2−STAT3 pathway, but not of the PI3K, ERK1/2, or PLC pathways. Conclusions IL-6 inhibits the inward TRPM7 current via the JAK2−STAT3 signaling pathway.
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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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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: 39] [Impact Index Per Article: 3.9] [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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Inactivation of TRPM7 kinase activity does not impair its channel function in mice. Sci Rep 2014; 4:5718. [PMID: 25030553 PMCID: PMC4101474 DOI: 10.1038/srep05718] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/23/2014] [Indexed: 11/30/2022] Open
Abstract
Transient receptor potential (TRP) family channels are involved in sensory pathways and respond to various environmental stimuli. Among the members of this family, TRPM7 is a unique fusion of an ion channel and a C-terminus kinase domain that is highly expressed in immune cells. TRPM7 serves as a key molecule governing cellular Mg2+ homeostasis in mammals since its channel pore is permeable to Mg2+ ions and can act as a Mg2+ influx pathway. However, mechanistic links between its kinase activity and channel function have remained uncertain. In this study, we generated kinase inactive knock-in mutant mice by mutagenesis of a key lysine residue involved in Mg2+-ATP binding. These mutant mice were normal in development and general locomotor activity. In peritoneal macrophages isolated from adult animals the basal activity of TRPM7 channels prior to cytoplasmic Mg2+ depletion was significantly potentiated, while maximal current densities measured after Mg2+ depletion were unchanged in the absence of detectable kinase function. Serum total Ca2+ and Mg2+ levels were not significantly altered in kinase-inactive mutant mice. Our findings suggest that abolishing TRPM7 kinase activity does not impair its channel activity and kinase activity is not essential for regulation of mammalian Mg2+ homeostasis.
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Inoue H, Murayama T, Tashiro M, Sakurai T, Konishi M. Mg(2+)- and ATP-dependent inhibition of transient receptor potential melastatin 7 by oxidative stress. Free Radic Biol Med 2014; 72:257-66. [PMID: 24747489 DOI: 10.1016/j.freeradbiomed.2014.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 11/25/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a Ca(2+)- and Mg(2+)-permeable nonselective cation channel that contains a unique carboxyl-terminal serine/threonine protein kinase domain. It has been reported that reactive oxygen species associated with hypoxia or ischemia activate TRPM7 current and then induce Ca(2+) overload resulting in neuronal cell death in the brain. In this study, we aimed to investigate the molecular mechanisms of TRPM7 regulation by hydrogen peroxide (H2O2) using murine TRPM7 expressed in HEK293 cells. Using the whole-cell patch-clamp technique, it was revealed that the TRPM7 current was inhibited, not activated, by the application of H2O2 to the extracellular solution. This inhibition was not reversed after washout or treatment with dithiothreitol, suggesting irreversible oxidation of TRPM7 or its regulatory factors by H2O2 under whole-cell recording. Application of an electrophile, N-methylmaleimide (NMM), which covalently modifies cysteine residues in proteins, also inhibited TRPM7 current irreversibly. The effects of H2O2 and NMM were dependent on free [Mg(2+)]i; the inhibition was stronger when cells were perfused with higher free [Mg(2+)]i solutions via pipette. In addition, TRPM7 current was not inhibited by H2O2 when millimolar ATP was included in the intracellular solution, even in the presence of substantial free [Mg(2+)]i, which is sufficient for TRPM7 inhibition by H2O2 in the absence of ATP. Moreover, a kinase-deficient mutant of TRPM7 (K1645R) was similarly inhibited by H2O2 just like the wild-type TRPM7 in a [Mg(2+)]i- and [ATP]i-dependent manner, indicating no involvement of the kinase activity of TRPM7. Thus, these data suggest that oxidative stress inhibits TRPM7 current under pathological conditions that accompany intracellular ATP depletion and free [Mg(2+)]i elevation.
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Affiliation(s)
- Hana Inoue
- Department of Physiology, Tokyo Medical University, 160-8402 Tokyo, Japan.
| | - Takashi Murayama
- Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Michiko Tashiro
- Department of Physiology, Tokyo Medical University, 160-8402 Tokyo, Japan
| | - Takashi Sakurai
- Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masato Konishi
- Department of Physiology, Tokyo Medical University, 160-8402 Tokyo, Japan
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Abstract
The channel kinases TRPM6 and TRPM7 are fusion proteins with an ion transport domain and an enzymatically active kinase domain. TRPM7 has been found in every mammalian tissue investigated to date. The two-in-one protein structure, the ubiquitous expression profile, and the protein's unique biophysical characteristics that enable divalent ion transport involve TRPM7 in a plethora of (patho)physiological processes. With its prominent role in cellular and systemic magnesium homeostasis, TRPM7 emerges as a key player in embryonic development, global ischemia, cardiovascular disease, and cancer.
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Affiliation(s)
- Andrea Fleig
- Center for Biomedical Research at The Queen's Medical Center, Honolulu, HI, USA,
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Lockwood TD. Lysosomal metal, redox and proton cycles influencing the CysHis cathepsin reaction. Metallomics 2013; 5:110-24. [PMID: 23302864 DOI: 10.1039/c2mt20156a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the 1930's pioneers discovered that maximal autolysis in tissue homogenates requires metal chelator, sulfhydryl reducing agent and acid pH. However, metals, reducing equivalents and protons (MR&P) have been overlooked as combined catalytic controls. Three categories of lysosomal machinery drive three distinguishable cycles importing and exporting MR&P. Zn(2+) preemptively inhibits CysHis catalysis under otherwise optimal protonation and reduction. Protein-bound cell Zn(2+) concentration is 200-2000 times the non-sequestered inhibitory concentration. Following autophagy, lysosomal proteolysis liberates much inhibitory Zn(2+). The vacuolar proton pump is the driving force for Zn(2+) export, as well as protonation of the peptidolytic mechanism. Other machinery of lysosomal cycles includes proton-driven Zn(2+) exporters (e.g. SLC11A1), Zn(2+) channels (e.g. TRPML-1), lysosomal thiol reductase, etc. The CysHis dyad is a sensor of the vacuolar environment of MR&P, an integrator of these simultaneous variables, and a catalytic responder. Rate-determination can shift between autophagic substrate acquisition (swallowing) and substrate degradation (digesting). Zn(2+) recycling from degraded proteins to new proteins is a fourth cycle that might pace lysosomal function under some conditions. Heritable insufficient or excess functions of CysHis cathepsins are associated with dysfunctional inflammation and immunity/auto-immunity, including diabetic pathogenesis.
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Affiliation(s)
- Thomas D Lockwood
- Dept. of Pharmacology, School of Medicine, Wright State University, Dayton, Ohio 45435, USA.
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Abstract
The physiological and clinical relevance of Mg(2+) has evolved over the last decades. The molecular identification of multiple Mg(2+) transporters (Acdp2, MagT1, Mrs2, Paracellin-1, SLC41A1, SLC41A2, TRPM6 and TRPM7) and their biophysical characterization in recent years has improved our understanding of Mg(2+) homeostasis regulation and has provided a basis for investigating the role of Mg(2+) in the immune system. Deletions and mutations of Mg(2+) transporters produce severe phenotypes with more systemic symptoms than those seen with Ca(2+) channel deletions, which tend to be more specific and less profound. Deficiency of the Mg(2+) permeable ion channels TRPM6 or TRPM7 in mice is lethal at embryonic day 12.5 or at day 6.5, respectively, and, even more surprisingly, chicken DT40 B cells lacking TRPM7 die after 24-48 h. Recent progress made in Mg(2+) research has helped to define underlying mechanisms of two hereditary diseases, human Hypomagnesemia (TRPM6 deletion) and X-chromosomal immunodeficiency (MagT1 deletion), and has revealed a potential new role for Mg(2+) as a second messenger. Future elucidation of human Mg(2+) transporters (Mrs2, SLC41A1, SLC41A2, TRPM7) expressed in immunocytes, beyond MagT1 and TRPM6, will widen our knowledge about the potential role of Mg(2+) in the activation of the immune response.
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Yu H, Zhang Z, Lis A, Penner R, Fleig A. TRPM7 is regulated by halides through its kinase domain. Cell Mol Life Sci 2013; 70:2757-71. [PMID: 23471296 DOI: 10.1007/s00018-013-1284-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/10/2013] [Accepted: 01/28/2013] [Indexed: 01/30/2023]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a divalent-selective cation channel fused to an atypical α-kinase. TRPM7 is a key regulator of cell growth and proliferation, processes accompanied by mandatory cell volume changes. Osmolarity-induced cell volume alterations regulate TRPM7 through molecular crowding of solutes that affect channel activity, including magnesium (Mg(2+)), Mg-nucleotides and a further unidentified factor. Here, we assess whether chloride and related halides can act as negative feedback regulators of TRPM7. We find that chloride and bromide inhibit heterologously expressed TRPM7 in synergy with intracellular Mg(2+) ([Mg(2+)]i) and this is facilitated through the ATP-binding site of the channel's kinase domain. The synergistic block of TRPM7 by chloride and Mg(2+) is not reversed during divalent-free or acidic conditions, indicating a change in protein conformation that leads to channel inactivation. Iodide has the strongest inhibitory effect on TRPM7 at physiological [Mg(2+)]i. Iodide also inhibits endogenous TRPM7-like currents as assessed in MCF-7 breast cancer cells, where upregulation of SLC5A5 sodium-iodide symporter enhances iodide uptake and inhibits cell proliferation. These results indicate that chloride could be an important factor in modulating TRPM7 during osmotic stress and implicate TRPM7 as a possible molecular mechanism contributing to the anti-proliferative characteristics of intracellular iodide accumulation in cancer cells.
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Affiliation(s)
- Haijie Yu
- Center for Biomedical Research, The Queen's Medical Center, 1301 Punchbowl St., Honolulu, HI 96813, USA
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Chokshi R, Fruasaha P, Kozak JA. 2-aminoethyl diphenyl borinate (2-APB) inhibits TRPM7 channels through an intracellular acidification mechanism. Channels (Austin) 2012; 6:362-9. [PMID: 22922232 DOI: 10.4161/chan.21628] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
2-APB is a widely used compound in ion channel research. It affects numerous channels including inositol 1,4,5-trisphosphate receptors, store-operated calcium channels and TRP channels, TRPV3 and TRPM7 among them. A characteristic property of TRPM7 channels is their sensitivity to intracellular Mg ( 2+) and pH. Using patch clamp electrophysiology we find that in Jurkat T lymphocytes, 100-300 µM extracellular 2-APB reversibly inhibits TRPM7 channels when internal HEPES concentration is low (1 mM). Increasing the concentration to 140 mM abolishes the 2-APB effect. Using single-cell fluorescence pH video imaging, we show that at concentrations of 100 µM and higher, 2-APB potently acidifies the cytoplasm. We conclude that TRPM7 sensitivity to 2-APB is not direct but rather, can be explained by cytoplasmic acidification and a resulting channel inhibition.
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Affiliation(s)
- Rikki Chokshi
- Department of Neuroscience, Wright State University, Dayton, OH, USA
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Chokshi R, Matsushita M, Kozak JA. Sensitivity of TRPM7 channels to Mg2+ characterized in cell-free patches of Jurkat T lymphocytes. Am J Physiol Cell Physiol 2012; 302:C1642-51. [PMID: 22460708 DOI: 10.1152/ajpcell.00037.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) channels were originally identified electrophysiologically when depletion of cytosolic Mg(2+) resulted in the gradual development of an outwardly rectifying cation current. Conversely, inclusion of millimolar Mg(2+) in internal solutions prevented activation of these channels in whole cell patch clamp. We recently demonstrated that the Jurkat T-cell whole cell TRPM7 channels are inhibited by internal Mg(2+) in a biphasic manner, displaying high [IC(50(1)) ≈ 10 μM] and low [IC(50(2)) ≈ 165 μM] affinity inhibitor sites. In that study, we had characterized the dependence of the maximum cell current density on intracellular Mg(2+) concentration. To characterize Mg(2+) inhibition in Jurkat T cells in more detail and compare it to whole cell results, we recorded single TRPM7 channels in cell-free membrane patches and investigated the dependence of their activity on Mg(2+) added on the cytoplasmic side. We systematically varied free Mg(2+) from 265 nM to 407 μM and evaluated the extent of channel inhibition in inside-out patch for 58 patches. We found that the TRPM7 channel shows two conductance levels of 39.0 pS (γ(1)) and 18.6 pS (γ(2)) and that both are reversibly inhibited by internal Mg(2+). The 39.0-pS conductance is the dominant state of the channel, observed most frequently in this recording configuration. The dose-response relation in inside-out patches shows a steeper Mg(2+) dependence than in whole cell, yielding IC(50(1)) of 25.1 μM and IC(50(2)) of 91.2 μM.. Single-channel analysis shows that the primary effect of Mg(2+) in multichannel patches is a reversible reduction of the number of conducting channels (N(o)). Additionally, at high Mg(2+) concentrations, we observed a saturating 20% reduction in unitary conductance (γ(1)). Thus Mg(2+) inhibition in whole cell can be explained by a drop in individual participating channels and a modest reduction in conductance. We also found that TRPM7 channels in some patches were not sensitive to this ion at submaximal Mg(2+) concentrations. Interestingly, Mg(2+) inhibition showed the property of use dependence: with repeated applications, Mg(2+) effect became gradually more potent, which suggests that Mg(2+) sensitivity of the channel is a dynamic characteristic that depends on other membrane factors.
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Affiliation(s)
- Rikki Chokshi
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, Ohio, USA
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