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The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity. Genetics 2017; 203:35-63. [PMID: 27183565 DOI: 10.1534/genetics.116.189357] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/07/2016] [Indexed: 12/12/2022] Open
Abstract
The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal's life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes.
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102
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Mass Spectrometric Analysis of TRPM6 and TRPM7 Phosphorylation Reveals Regulatory Mechanisms of the Channel-Kinases. Sci Rep 2017; 7:42739. [PMID: 28220887 PMCID: PMC5318989 DOI: 10.1038/srep42739] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/12/2017] [Indexed: 01/23/2023] Open
Abstract
TRPM7 and TRPM6 were the first identified bifunctional channels to contain their own kinase domains, but how these channel-kinases are regulated is poorly understood. Previous studies identified numerous phosphorylation sites on TRPM7, but very little is known about TRPM6 phosphorylation or sites on TRPM7 transphosphorylated by TRPM6. Our mass spectrometric analysis of homomeric and heteromeric TRPM7 and TRPM6 channels identified phosphorylation sites on both proteins, as well as several prominent sites on TRPM7 that are commonly modified through autophosphorylation and transphosphorylation by TRPM6. We conducted a series of amino acid substitution analyses and identified S1777, in TRPM7’s catalytic domain, and S1565, in TRPM7’s exchange domain that mediates kinase dimerization, as potential regulatory sites. The phosphomimetic S1777D substitution disrupted catalytic activity, most likely by causing an electrostatic perturbation at the active site. The S1565D phosphomimetic substitution also inactivated the kinase but did so without interfering with kinase dimerization. Molecular modeling indicates that phosphorylation of S1565 is predicted to structurally affect TRPM7’s functionally conserved N/D loop, which is thought to influence the access of substrate to the active site pocket. We propose that phosphorylation of S1565 within the exchange domain functions as a regulatory switch to control TRPM7 catalytic activity.
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Bernhardt ML, Padilla-Banks E, Stein P, Zhang Y, Williams CJ. Store-operated Ca 2+ entry is not required for fertilization-induced Ca 2+ signaling in mouse eggs. Cell Calcium 2017; 65:63-72. [PMID: 28222911 DOI: 10.1016/j.ceca.2017.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 01/01/2023]
Abstract
Repetitive oscillations in cytoplasmic Ca2+ due to periodic Ca2+ release from the endoplasmic reticulum (ER) drive mammalian embryo development following fertilization. Influx of extracellular Ca2+ to support the refilling of ER stores is required for sustained Ca2+ oscillations, but the mechanisms underlying this Ca2+ influx are controversial. Although store-operated Ca2+ entry (SOCE) is an appealing candidate mechanism, several groups have arrived at contradictory conclusions regarding the importance of SOCE in oocytes and eggs. To definitively address this question, Ca2+ influx was assessed in oocytes and eggs lacking the major components of SOCE, the ER Ca2+ sensor STIM proteins, and the plasma membrane Ca2+ channel ORAI1. We generated oocyte-specific conditional knockout (cKO) mice for Stim1 and Stim2, and also generated Stim1/2 double cKO mice. Females lacking one or both STIM proteins were fertile and their ovulated eggs displayed normal patterns of Ca2+ oscillations following fertilization. In addition, no impairment was observed in ER Ca2+ stores or Ca2+ influx following store depletion. Similar studies were performed on eggs from mice globally lacking ORAI1; no abnormalities were observed. Furthermore, spontaneous Ca2+ influx was normal in oocytes from Stim1/2 cKO and ORAI1-null mice. Finally, we tested if TRPM7-like channels could support spontaneous Ca2+ influx, and found that it was largely prevented by NS8593, a TRPM7-specific inhibitor. Fertilization-induced Ca2+ oscillations were also impaired by NS8593. Combined, these data robustly show that SOCE is not required to support appropriate Ca2+ signaling in mouse oocytes and eggs, and that TRPM7-like channels may contribute to Ca2+ influx that was previously attributed to SOCE.
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Affiliation(s)
- Miranda L Bernhardt
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Elizabeth Padilla-Banks
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Paula Stein
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yingpei Zhang
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Carmen J Williams
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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104
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Bittremieux M, Gerasimenko JV, Schuermans M, Luyten T, Stapleton E, Alzayady KJ, De Smedt H, Yule DI, Mikoshiba K, Vangheluwe P, Gerasimenko OV, Parys JB, Bultynck G. DPB162-AE, an inhibitor of store-operated Ca 2+ entry, can deplete the endoplasmic reticulum Ca 2+ store. Cell Calcium 2017; 62:60-70. [PMID: 28196740 DOI: 10.1016/j.ceca.2017.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/27/2017] [Accepted: 01/27/2017] [Indexed: 02/05/2023]
Abstract
Store-operated Ca2+ entry (SOCE), an important Ca2+ signaling pathway in non-excitable cells, regulates a variety of cellular functions. To study its physiological role, pharmacological tools, like 2-aminoethyl diphenylborinate (2-APB), are used to impact SOCE. 2-APB is one of the best characterized SOCE inhibitors. However, 2-APB also activates SOCE at lower concentrations, while it inhibits inositol 1,4,5-trisphosphate receptors (IP3Rs), sarco/endoplasmic reticulum Ca2+-ATPases (SERCAs) and other ion channels, like TRP channels. Because of this, 2-APB analogues that inhibit SOCE more potently and more selectively compared to 2-APB have been developed. The recently developed DPB162-AE is such a structural diphenylborinate isomer of 2-APB that selectively inhibits SOCE currents by blocking the functional coupling between STIM1 and Orai1. However, we observed an adverse effect of DPB162-AE on the ER Ca2+-store content at concentrations required for complete SOCE inhibition. DPB162-AE increased the cytosolic Ca2+ levels by reducing the ER Ca2+ store in cell lines as well as in primary cells. DPB162-AE did not affect SERCA activity, but provoked a Ca2+ leak from the ER, even after application of the SERCA inhibitor thapsigargin. IP3Rs partly contributed to the DPB162-AE-induced Ca2+ leak, since pharmacologically and genetically inhibiting IP3R function reduced, but not completely blocked, the effects of DPB162-AE on the ER store content. Our results indicate that, in some conditions, the SOCE inhibitor DPB162-AE can reduce the ER Ca2+-store content by inducing a Ca2+-leak pathway at concentrations needed for adequate SOCE inhibition.
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Affiliation(s)
- Mart Bittremieux
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, 3000 Leuven, Belgium
| | - Julia V Gerasimenko
- Cardiff University, MCR Secretory Control Research Group, Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, Wales, UK
| | - Marleen Schuermans
- KU Leuven, Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, 3000 Leuven, Belgium
| | - Tomas Luyten
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, 3000 Leuven, Belgium
| | - Eloise Stapleton
- Cardiff University, MCR Secretory Control Research Group, Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, Wales, UK
| | - Kamil J Alzayady
- University of Rochester, Department of Pharmacology and Physiology, Rochester, NY 14642, USA
| | - Humbert De Smedt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, 3000 Leuven, Belgium
| | - David I Yule
- University of Rochester, Department of Pharmacology and Physiology, Rochester, NY 14642, USA
| | - Katsuhiko Mikoshiba
- The Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Peter Vangheluwe
- KU Leuven, Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, 3000 Leuven, Belgium
| | - Oleg V Gerasimenko
- Cardiff University, MCR Secretory Control Research Group, Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, Wales, UK
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, 3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, 3000 Leuven, Belgium.
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105
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Song C, Bae Y, Jun J, Lee H, Kim ND, Lee KB, Hur W, Park JY, Sim T. Identification of TG100-115 as a new and potent TRPM7 kinase inhibitor, which suppresses breast cancer cell migration and invasion. Biochim Biophys Acta Gen Subj 2017; 1861:947-957. [PMID: 28161478 DOI: 10.1016/j.bbagen.2017.01.034] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Transient receptor potential melastatin 7 (TRPM7) regulates breast cancer cell proliferation, migration, invasion and metastasis in its ion channel- and kinase domain-dependent manner. The pharmacological effects of TRPM7 ion channel inhibitors on breast cancer cells have been studied, but little is known about the effects of TRPM7 kinase domain inhibitors due to lack of potent TRPM7 kinase inhibitors. METHODS Screening was performed by using TRPM7 kinase assay. Effects of TG100-115 on breast cancer cell proliferation, migration, invasion, myosin IIA phosphorylation, and TRPM7 ion channel activity were assessed by using MTT, wound healing, transwell assay, Western blotting, and patch clamping, respectively. RESULTS We found that CREB peptide is a potent substrate for the TR-FRET based TRPM7 kinase assay. Using this method, we discovered a new and potent TRPM7 kinase inhibitor, TG100-115. TG100-115 inhibited TRPM7 kinase activity in an ATP competitive fashion with over 70-fold stronger activity than that of rottlerin, known as a TRPM7 kinase inhibitor. TG100-115 has little effect on proliferation of MDA-MB-231 cells, but significantly decreases cell migration and invasion. Moreover, TG100-115 inhibits TRPM7 kinase regulated phosphorylation of the myosin IIA heavy chain and phosphorylation of focal adhesion kinase. TG100-115 also suppressed TRPM7 ion channel activity. CONCLUSIONS TG100-115 can be used as a potent TRPM7 kinase inhibitor and a potent inhibitor of breast cancer cell migration. GENERAL SIGNIFICANCE TG100-115 could be a useful tool for studying the pharmacological effects of TRPM7 kinase activity aimed at providing insight into new therapeutic approaches to the treatment of breast cancer.
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Affiliation(s)
- Chiman Song
- Chemical Kinomics Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Yeonju Bae
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - JinJoo Jun
- Chemical Kinomics Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Hyomin Lee
- Chemical Kinomics Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biological Chemistry, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Nam Doo Kim
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Kyung-Bok Lee
- Division of Life Science, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Wooyoung Hur
- Chemical Kinomics Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biological Chemistry, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - Taebo Sim
- Chemical Kinomics Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea.
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106
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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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107
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CHEUNG JOSEPHY, MILLER BARBARAA. Transient Receptor Potential-Melastatin Channel Family Member 2: Friend or Foe. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2017; 128:308-329. [PMID: 28790515 PMCID: PMC5525431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transient receptor potential melastatin 2 (Trpm2) channels are nonvoltage-activated channels permeable to monovalent and divalent cations, and are expressed in heart, brain, kidney, vasculature, and hematopoietic cells. Trpm2 is overexpressed in bladder, lung, breast, liver, head, and neck cancers. Classically, Trpm2 activation induces cell injury and death by Ca2+ overload or enhanced inflammatory response. Recent studies show that Trpm2 protects lungs from endotoxin-induced injury by reducing reactive oxygen species production in phagocytes; and improves cardiac function after ischemia-reperfusion injury by preserving mitochondrial respiration and cellular adenosine triphosphate levels while decreasing reactive oxygen species levels. In neuroblastoma xenografts, Trpm2 overexpression promotes tumor growth through modulation of hypoxia-inducible transcription factor expression and cellular bioenergetics; whereas Trpm2 inhibition results in enhanced sensitivity to doxorubicin. The robust expression in cancer cells and its pro-survival and proliferative properties make Trpm2 a rational target for cancer therapy. Indiscriminate Trpm2 inhibition, however, may engender serious untoward side effects in other vital organs.
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Affiliation(s)
- JOSEPH Y. CHEUNG
- Correspondence and reprint requests: Joseph Y. Cheung, MD, PhD,
Department of Medicine, Lewis Katz School of Medicine of Temple University, 3401 N. Broad Street, Suite 807, Philadelphia, Pennsylvania 19140
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108
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Suzuki Y, Watanabe M, Saito CT, Tominaga M. Expression of the TRPM6 in mouse placental trophoblasts; potential role in maternal-fetal calcium transport. J Physiol Sci 2017; 67:151-162. [PMID: 27043350 PMCID: PMC10717052 DOI: 10.1007/s12576-016-0449-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/20/2016] [Indexed: 12/14/2022]
Abstract
The placenta is required to transport calcium (Ca2+) from mother to fetus during fetal bone mineralization. In an attempt to clarify the molecular basis of Ca2+ entry for this transport, we identified TRPM6 as a candidate for apical Ca2+ entry pathway. TRPM6 mRNA increased during the last 4 days of pregnancy, coinciding with fetal bone mineralization in mice. TRPM6 mRNA and protein was localized in the trophoblasts in labyrinth where the maternal-fetal Ca2+ transport occurs. In patch-clamp recordings, we observed TRPM6/TRPM7-like currents in mouse trophoblasts after starting fetal bone mineralization but not before mineralization. Plasma membrane Ca2+ permeability was significantly increased in TRPM6/TRPM7 expressed HEK293 cells under physiological Mg2+ and ATP concentration but not in TRPM6 or TRPM7 homomer-expressing cells. These results suggest that TRPM6 is functionally expressed in mouse placental trophoblasts, implicating in maternal-fetal Ca2+ transport likely with TRPM7, which might enable to sustain fetal bone mineralization.
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Affiliation(s)
- Yoshiro Suzuki
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, 444-8787, Japan.
| | - Masaki Watanabe
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan
- Department of Renal and Urologic Surgery, Asahikawa Medical University, Asahikawa, 078-8510, Japan
| | - Claire T Saito
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, 444-8787, Japan.
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109
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Komiya Y, Runnels LW. TRPM channels and magnesium in early embryonic development. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2016; 59:281-8. [PMID: 26679946 DOI: 10.1387/ijdb.150196lr] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Magnesium (Mg(2+)) is the second most abundant cellular cation and is essential for all stages of life, from the early embryo to adult. Mg(2+) deficiency causes or contributes to many human diseases, including migraine headaches, Parkinson's disease, Alzheimer's disease, hypotension, type 2 diabetes mellitus and cardiac arrhythmias. Although the concentration of Mg(2+) in the extracellular environment can vary significantly, the total intracellular Mg(2+) concentration is actively maintained within a relatively narrow range (14 - 20 mM) via tight, yet poorly understood, regulation of intracellular Mg(2+)by Mg(2+) transporters and Mg(2+)-permeant ion channels. Recent studies have continued to add to the growing number of Mg(2+) transporters and ion channels involved in Mg(2+) homeostasis, including TRPM6 and TRPM7, members of the transient receptor potential (TRP) ion channel family. Mutations in TRPM6, including amino acid substitutions that prevent its heterooligomerization with TRPM7, occur in the rare autosomal-recessive disease hypomagnesemia with secondary hypocalcemia (HSH). Genetic ablation of either gene in mice results in early embryonic lethality, raising the question of whether these channels' capacity to mediate Mg(2+) influx plays an important role in embryonic development. Here we review what is known of the function of Mg(2+) in early development and summarize recent findings regarding the function of the TRPM6 and TRPM7 ion channels during embryogenesis.
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Affiliation(s)
- Yuko Komiya
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ, USA
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110
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Bao L, Chen SJ, Conrad K, Keefer K, Abraham T, Lee JP, Wang J, Zhang XQ, Hirschler-Laszkiewicz I, Wang HG, Dovat S, Gans B, Madesh M, Cheung JY, Miller BA. Depletion of the Human Ion Channel TRPM2 in Neuroblastoma Demonstrates Its Key Role in Cell Survival through Modulation of Mitochondrial Reactive Oxygen Species and Bioenergetics. J Biol Chem 2016; 291:24449-24464. [PMID: 27694440 DOI: 10.1074/jbc.m116.747147] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/29/2016] [Indexed: 12/13/2022] Open
Abstract
Transient receptor potential melastatin 2 (TRPM2) ion channel has an essential function in modulating cell survival following oxidant injury and is highly expressed in many cancers including neuroblastoma. Here, in xenografts generated from neuroblastoma cells in which TRPM2 was depleted with CRISPR/Cas9 technology and in in vitro experiments, tumor growth was significantly inhibited and doxorubicin sensitivity increased. The hypoxia-inducible transcription factor 1/2α (HIF-1/2α) signaling cascade including proteins involved in oxidant stress, glycolysis, and mitochondrial function was suppressed by TRPM2 depletion. TRPM2-depleted SH-SY5Y neuroblastoma cells demonstrated reduced oxygen consumption and ATP production after doxorubicin, confirming impaired cellular bioenergetics. In cells in which TRPM2 was depleted, mitochondrial superoxide production was significantly increased, particularly following doxorubicin. Ectopic expression of superoxide dismutase 2 (SOD2) reduced ROS and preserved viability of TRPM2-depleted cells, however, failed to restore ATP levels. Mitochondrial reactive oxygen species (ROS) were also significantly increased in cells in which TRPM2 function was inhibited by TRPM2-S, and pretreatment of these cells with the antioxidant MitoTEMPO significantly reduced ROS levels in response to doxorubicin and protected cell viability. Expression of the TRPM2 pore mutant E960D, in which calcium entry through TRPM2 is abolished, also resulted in significantly increased mitochondrial ROS following doxorubicin treatment, showing the critical role of TRPM2-mediated calcium entry. These findings demonstrate the important function of TRPM2 in modulation of cell survival through mitochondrial ROS, and the potential of targeted inhibition of TRPM2 as a therapeutic approach to reduce cellular bioenergetics, tumor growth, and enhance susceptibility to chemotherapeutic agents.
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Affiliation(s)
- Lei Bao
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Shu-Jen Chen
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Kathleen Conrad
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Kerry Keefer
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Thomas Abraham
- Neural and Behavioral Sciences and Microscopy Imaging Facility
| | - John P Lee
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - JuFang Wang
- the Departments of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140; The Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Xue-Qian Zhang
- the Departments of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140; The Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Iwona Hirschler-Laszkiewicz
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Hong-Gang Wang
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; Departments of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Sinisa Dovat
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Brian Gans
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Muniswamy Madesh
- The Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140; Molecular Genetics and Medical Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Joseph Y Cheung
- the Departments of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140; The Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Barbara A Miller
- Departments of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and.
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111
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Carvacho I, Ardestani G, Lee HC, McGarvey K, Fissore RA, Lykke-Hartmann K. TRPM7-like channels are functionally expressed in oocytes and modulate post-fertilization embryo development in mouse. Sci Rep 2016; 6:34236. [PMID: 27681336 PMCID: PMC5041074 DOI: 10.1038/srep34236] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/05/2016] [Indexed: 01/16/2023] Open
Abstract
The Transient Receptor Potential (TRP) channels are a family of cationic ion channels widely distributed in mammalian tissues. In general, the global genetic disruption of individual TRP channels result in phenotypes associated with impairment of a particular tissue and/or organ function. An exception is the genetic ablation of the TRP channel TRPM7, which results in early embryonic lethality. Nevertheless, the function of TRPM7 in oocytes, eggs and pre-implantation embryos remains unknown. Here, we described an outward rectifying non-selective current mediated by a TRP ion channel in immature oocytes (germinal vesicle stage), matured oocytes (metaphase II eggs) and 2-cell stage embryos. The current is activated by specific agonists and inhibited by distinct blockers consistent with the functional expression of TRPM7 channels. We demonstrated that the TRPM7-like channels are homo-tetramers and their activation mediates calcium influx in oocytes and eggs, which is fundamental to support fertilization and egg activation. Lastly, we showed that pharmacological inhibition of the channel function delays pre-implantation embryo development and reduces progression to the blastocyst stage. Our data demonstrate functional expression of TRPM7-like channels in mouse oocytes, eggs and embryos that may play an essential role in the initiation of embryo development.
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Affiliation(s)
- Ingrid Carvacho
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Department of Biology and Chemistry, Faculty of Basic Sciences, Universidad Católica del Maule, 3480112 Talca, Chile
| | - Goli Ardestani
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Hoi Chang Lee
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Kaitlyn McGarvey
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus Institute of Advanced Studies (AIAS), Aarhus University, DK-8000 Aarhus C, Denmark
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Valinsky WC, Jolly A, Miquel P, Touyz RM, Shrier A. Aldosterone Upregulates Transient Receptor Potential Melastatin 7 (TRPM7). J Biol Chem 2016; 291:20163-72. [PMID: 27466368 PMCID: PMC5025699 DOI: 10.1074/jbc.m116.735175] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/26/2016] [Indexed: 12/18/2022] Open
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a ubiquitously expressed Mg(2+)-permeable ion channel fused to a C-terminal α-kinase domain. Recently, aldosterone was shown to increase intracellular Mg(2+) levels and alter inflammatory signaling in TRPM7-expressing HEK293 cells. This study was undertaken to assess whether these effects were related to an aldosterone-mediated increase of TRPM7 current and/or plasma membrane localization. Using HEK293 cells stably expressing WT-TRPM7, we found that 18-h application of aldosterone significantly increased TRPM7 current and TRPM7 plasma membrane protein expression by 48% and 34%, respectively. The aldosterone-mediated increase of TRPM7 current was inhibited by eplerenone, a mineralocorticoid receptor (MR) blocker, and GSK-650394, an inhibitor of the serum- and glucocorticoid-regulated kinase 1 (SGK1). SGK1 blockade also prevented the aldosterone-induced increase of TRPM7 plasma membrane protein. It was further determined that K1648R-TRPM7, the phosphotransferase-inactive TRPM7 mutant, was unresponsive to aldosterone. Therefore, chronic aldosterone treatment increases the plasma membrane expression of TRPM7, which is associated with an increase of TRPM7 current. This process occurs via an MR-dependent, genomic signaling cascade involving SGK1 and a functioning TRPM7 α-kinase domain. We suggest that this mechanism may be of general relevance when interpreting the effects of aldosterone because the MR receptor is found in multiple tissues, and TRPM7 and SGK1 are ubiquitously expressed.
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Affiliation(s)
- William C Valinsky
- From the Department of Physiology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Anna Jolly
- From the Department of Physiology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Perrine Miquel
- From the Department of Physiology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Rhian M Touyz
- the Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF GCRC, 126 University Place, Glasgow G12 8TA, United Kingdom
| | - Alvin Shrier
- From the Department of Physiology, McGill University, Montreal, Quebec H3G 0B1, Canada and
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113
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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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114
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Robak P, Ożgo M, Michałek K, Kolasa-Wołosiuk A, Taciak M, Barszcz M, Marynowska M. Identification of TRPM6 and TRPM7 expression changes in response to a diet supplemented with inulin in porcine kidney. Arch Anim Breed 2016. [DOI: 10.5194/aab-59-267-2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract. Magnesium is the fourth most abundant mineral element in vertebrates and the second most common intracellular cation. Recently identified Mg2+-specific channels – TRPM6 and TRPM7 – have been shown to be essential for whole-body and cellular Mg2+ homeostasis. The aim of the study was to determine the effect of inulin on the expression of TRPM6 and TRPM7 in the renal cortex and medulla of growing pigs. The study was carried out on 16 Danbred × Duroc castrated male piglets fed a cereal-based diet without inulin or with 2 % addition of inulin from chicory root from the 10th day of life. In pigs fed a diet with inulin, TRPM6 expression was greater in both the renal cortex and medulla compared to the control group. The expression of TRPM7 in both the renal cortex and medulla in the control group and in piglets fed a diet enriched with inulin was relatively stable. To our knowledge, this is the first study aimed at the identification of TRPM6 and TRPM7 in the kidneys of pig. It is proposed that inulin addition to fodder resulted not only in a magnesium absorption increase, but also, due to prolonged low plasma Mg concentration of examined piglets, renal magnesium retention. Therefore, higher magnesium reabsorption via increased TRPM6 expression in the kidney was probably observed in order to supplement deficiencies of this element. Diet-unresponsive expression of TRPM7 supports the concept that this channel is not involved in the extracellular magnesium homeostasis.
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115
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Echeverry S, Rodriguez MJ, Torres YP. Transient Receptor Potential Channels in Microglia: Roles in Physiology and Disease. Neurotox Res 2016; 30:467-78. [PMID: 27260222 DOI: 10.1007/s12640-016-9632-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 05/12/2016] [Accepted: 05/18/2016] [Indexed: 12/21/2022]
Abstract
Microglia modulate the nervous system cellular environment and induce neuroprotective and neurotoxic effects. Various molecules are involved in these processes, including families of ion channels expressed in microglial cells, such as transient receptor potential (TRP) channels. TRP channels comprise a family of non-selective cation channels that can be activated by mechanical, thermal, and chemical stimuli, and which contribute to the regulation of intracellular calcium concentrations. TRP channels have been shown to be involved in cellular processes such as osmotic regulation, cytokine production, proliferation, activation, cell death, and oxidative stress responses. Given the significance of these processes in microglial activity, studies of TRP channels in microglia have focused on determining their roles in both neuroprotective and neurotoxic processes. TRP channel activity has been proposed to play an important function in neurodegenerative diseases, ischemia, inflammatory responses, and neuropathic pain. Modulation of TRP channel activity may thus be considered as a potential therapeutic strategy for the treatment of various diseases associated with alterations of the central nervous system (CNS). In this review, we describe the expression of different subfamilies of TRP channels in microglia, focusing on their physiological and pathophysiological roles, and consider their potential use as therapeutic targets in CNS diseases.
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Affiliation(s)
- Santiago Echeverry
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 # 40-62, Bogotá, Colombia
| | - María Juliana Rodriguez
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 # 40-62, Bogotá, Colombia
| | - Yolima P Torres
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 # 40-62, Bogotá, Colombia.
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116
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Wu X, Indzhykulian AA, Niksch PD, Webber RM, Garcia-Gonzalez M, Watnick T, Zhou J, Vollrath MA, Corey DP. Hair-Cell Mechanotransduction Persists in TRP Channel Knockout Mice. PLoS One 2016; 11:e0155577. [PMID: 27196058 PMCID: PMC4873267 DOI: 10.1371/journal.pone.0155577] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/01/2016] [Indexed: 12/17/2022] Open
Abstract
Members of the TRP superfamily of ion channels mediate mechanosensation in some organisms, and have been suggested as candidates for the mechanotransduction channel in vertebrate hair cells. Some TRP channels can be ruled out based on lack of an inner ear phenotype in knockout animals or pore properties not similar to the hair-cell channel. Such studies have excluded Trpv4, Trpa1, Trpml3, Trpm1, Trpm3, Trpc1, Trpc3, Trpc5, and Trpc6. However, others remain reasonable candidates. We used data from an RNA-seq analysis of gene expression in hair cells as well as data on TRP channel conductance to narrow the candidate group. We then characterized mice lacking functional Trpm2, Pkd2, Pkd2l1, Pkd2l2 and Pkd1l3, using scanning electron microscopy, auditory brainstem response, permeant dye accumulation, and single-cell electrophysiology. In all of these TRP-deficient mice, and in double and triple knockouts, mechanotransduction persisted. Together with published studies, these results argue against the participation of any of the 33 mouse TRP channels in hair cell transduction.
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MESH Headings
- Animals
- Calcium Channels/genetics
- Cochlea/physiology
- Ear, Inner/physiology
- Evoked Potentials, Auditory, Brain Stem/genetics
- Gene Expression Profiling
- Gene Expression Regulation
- Hair Cells, Auditory/physiology
- Hearing
- Mechanotransduction, Cellular
- Membrane Glycoproteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Electron, Scanning
- Patch-Clamp Techniques
- Receptors, Cell Surface/genetics
- TRPM Cation Channels/genetics
- TRPP Cation Channels/genetics
- Transient Receptor Potential Channels/genetics
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Affiliation(s)
- Xudong Wu
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Artur A. Indzhykulian
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Paul D. Niksch
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Roxanna M. Webber
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Miguel Garcia-Gonzalez
- Department of Medicine, Division of Nephrology, University of Maryland, Baltimore, Maryland, United States of America
| | - Terry Watnick
- Department of Medicine, Division of Nephrology, University of Maryland, Baltimore, Maryland, United States of America
| | - Jing Zhou
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Melissa A. Vollrath
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- Department of Physiology, McGill University Montréal, Québec, Canada
| | - David P. Corey
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- * E-mail:
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117
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Nörenberg W, Plötz T, Sobottka H, Chubanov V, Mittermeier L, Kalwa H, Aigner A, Schaefer M. TRPM7 is a molecular substrate of ATP-evoked P2X7-like currents in tumor cells. J Gen Physiol 2016; 147:467-83. [PMID: 27185858 PMCID: PMC4886280 DOI: 10.1085/jgp.201611595] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/20/2016] [Indexed: 12/12/2022] Open
Abstract
Extracellular ATP activates receptors such as P2X ligand-gated ion channels, but it also chelates divalent cations. Nörenberg et al. find that experimental conditions designed to measure P2X7 activity also activate TRPM7 channels, by relieving inhibition by extracellular divalent cations, in HEK293 and rat C6 glioma cells. Within the ion channel–coupled purine receptor (P2X) family, P2X7 has gained particular interest because of its role in immune responses and in the growth control of several malignancies. Typical hallmarks of P2X7 are nonselective and noninactivating cation currents that are elicited by high concentrations (0.1–10 mM) of extracellular ATP. Here, we observe spurious ATP-induced currents in HEK293 cells that neither express P2X7 nor display ATP-induced Ca2+ influx or Yo-Pro-1 uptake. Although the biophysical properties of these ionic currents resemble those of P2X7 in terms of their reversal potential close to 0 mV, nonrectifying current-voltage relationship, current run-up during repeated ATP application, and augmentation in bath solutions containing low divalent cation (DIC) concentrations, they are poorly inhibited by established P2X7 antagonists. Because high ATP concentrations reduce the availability of DICs, these findings prompted us to ask whether other channel entities may become activated by our experimental regimen. Indeed, a bath solution with no added DICs yields similar currents and also a rapidly inactivating Na+-selective conductance. We provide evidence that TRPM7 and ASIC1a (acid-sensing ion channel type Ia)-like channels account for these noninactivating and phasic current components, respectively. Furthermore, we find ATP-induced currents in rat C6 glioma cells, which lack functional P2X receptors but express TRPM7. Thus, the observation of an atypical P2X7-like conductance may be caused by the activation of TRPM7 by ATP, which scavenges free DICs and thereby releases TRPM7 from permeation block. Because TRPM7 has a critical role in controlling the intracellular Mg2+ homeostasis and regulating tumor growth, these data imply that the proposed role of P2X7 in C6 glioma cell proliferation deserves reevaluation.
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Affiliation(s)
- Wolfgang Nörenberg
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
| | - Tanja Plötz
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
| | - Helga Sobottka
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
| | - Vladimir Chubanov
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilian University of Munich, 80336 Munich, Germany
| | - Lorenz Mittermeier
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilian University of Munich, 80336 Munich, Germany
| | - Hermann Kalwa
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
| | - Achim Aigner
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
| | - Michael Schaefer
- Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, Leipzig University, 04107 Leipzig, Germany
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118
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Extracellular Calcium Has Multiple Targets to Control Cell Proliferation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:133-56. [DOI: 10.1007/978-3-319-26974-0_7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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119
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Kim BJ, Hong C. Role of transient receptor potential melastatin type 7 channel in gastric cancer. Integr Med Res 2016; 5:124-130. [PMID: 28462107 PMCID: PMC5381434 DOI: 10.1016/j.imr.2016.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 01/11/2023] Open
Abstract
Transient receptor potential (TRP) proteins are a family of ion channels, which are responsible for a wide array of cellular functions. In particular, TRP melastatin type (TRPM) 7 is expressed everywhere and permeable to divalent cations such as Mg2+ and Ca2+. It contains a channel and a kinase domain. Recent studies indicate that activation of TRPM7 plays an important role in the growth and survival of gastric cancer cells. In this review, we describe and discuss the findings of recent studies that have provided novel insights of the relation between TRPM7 and gastric cancer.
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Affiliation(s)
- Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.,Healthy Aging Korean Medical Research Center, School of Korean Medicine, Pusan National University, Yangsan, Korea
| | - Chansik Hong
- Department of Physiology, Seoul National University, College of Medicine, Seoul, Korea
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120
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MLKL forms cation channels. Cell Res 2016; 26:517-28. [PMID: 27033670 PMCID: PMC4856759 DOI: 10.1038/cr.2016.26] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 12/17/2022] Open
Abstract
The mixed lineage kinase domain-like (MLKL) protein is a key factor in tumor necrosis factor-induced necroptosis. Recent studies on necroptosis execution revealed a commitment role of MLKL in membrane disruption. However, our knowledge of how MLKL functions on membrane remains very limited. Here we demonstrate that MLKL forms cation channels that are permeable preferentially to Mg2+ rather than Ca2+ in the presence of Na+ and K+. Moreover, the N-terminal domain containing six helices (H1-H6) is sufficient to form channels. Using the substituted cysteine accessibility method, we further determine that helix H1, H2, H3, H5 and H6 are transmembrane segments, while H4 is located in the cytoplasm. Finally, MLKL-induced membrane depolarization and cell death exhibit a positive correlation to its channel activity. The Mg2+-preferred permeability and five transmembrane segment topology distinguish MLKL from previously identified Mg2+-permeable channels and thus establish MLKL as a novel class of cation channels.
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121
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Lee HC, Yoon SY, Lykke-Hartmann K, Fissore RA, Carvacho I. TRPV3 channels mediate Ca2+ influx induced by 2-APB in mouse eggs. Cell Calcium 2016; 59:21-31. [DOI: 10.1016/j.ceca.2015.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 12/09/2015] [Accepted: 12/11/2015] [Indexed: 11/29/2022]
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122
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Geng Y, Feng B. Mesendogen, a novel inhibitor of TRPM6, promotes mesoderm and definitive endoderm differentiation of human embryonic stem cells through alteration of magnesium homeostasis. Heliyon 2015; 1:e00046. [PMID: 26705539 PMCID: PMC4685751 DOI: 10.1016/j.heliyon.2015.e00046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The homo- and hetero-tetrameric channel complexes formed by transient receptor potential cation channel, subfamily M, member 6 (TRPM6) and 7 (TRPM7) (collectively referred to as TRPM6/TRPM7 channels in this study) are the major regulators of cellular magnesium uptake, yet the exact roles of TRPM6/TRPM7 channels and cellular magnesium homeostasis during development are poorly understood. Here, we report a novel small molecule Mesendogen (MEG) which robustly induces nearly homogeneous (≥85%) mesoderm and definitive endoderm (DE) differentiations of human embryonic stem cells (hESCs) in combination with growth factors. A kinome screen followed by loss-of-function experiments identified TRPM6 as the biological target of MEG. We demonstrated that MEG functions by inhibiting TRPM6/TRPM7 magnesium channel activity, as MEG reduced intracellular magnesium level, while TRPM6/TRPM7 channel modulation and magnesium-withdrawal phenocopied MEG at enhancing mesoderm and DE differentiations. This study discovers a robust chemical enhancer of hESC directed differentiation, and uncovers a novel regulatory role of cellular magnesium homeostasis during early embryonic cell fate specification.
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Affiliation(s)
- Yijie Geng
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Bradley Feng
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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123
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Tsujikawa H, Yu AS, Xie J, Yue Z, Yang W, He Y, Yue L. Identification of key amino acid residues responsible for internal and external pH sensitivity of Orai1/STIM1 channels. Sci Rep 2015; 5:16747. [PMID: 26576490 PMCID: PMC4649748 DOI: 10.1038/srep16747] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 10/20/2015] [Indexed: 12/27/2022] Open
Abstract
Changes of intracellular and extracellular pH are involved in a variety of physiological and pathological processes, in which regulation of the Ca2+ release activated Ca2+ channel (ICRAC) by pH has been implicated. Ca2+ entry mediated by ICRAC has been shown to be regulated by acidic or alkaline pH. Whereas several amino acid residues have been shown to contribute to extracellular pH (pHo) sensitivity, the molecular mechanism for intracellular pH (pHi) sensitivity of Orai1/STIM1 is not fully understood. By investigating a series of mutations, we find that the previously identified residue E106 is responsible for pHo sensitivity when Ca2+ is the charge carrier. Unexpectedly, we identify that the residue E190 is responsible for pHo sensitivity when Na+ is the charge carrier. Furthermore, the intracellular mutant H155F markedly diminishes the response to acidic and alkaline pHi, suggesting that H155 is responsible for pHi sensitivity of Orai1/STIM1. Our results indicate that, whereas H155 is the intracellular pH sensor of Orai1/STIM1, the molecular mechanism of external pH sensitivity varies depending on the permeant cations. As changes of pH are involved in various physiological/pathological functions, Orai/STIM channels may be an important mediator for various physiological and pathological processes associated with acidosis and alkalinization.
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Affiliation(s)
- Hiroto Tsujikawa
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Albert S Yu
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Jia Xie
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Zhichao Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Wenzhong Yang
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Yanlin He
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Lixia Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
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124
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Castiglioni S, Cazzaniga A, Trapani V, Cappadone C, Farruggia G, Merolle L, Wolf FI, Iotti S, Maier JAM. Magnesium homeostasis in colon carcinoma LoVo cells sensitive or resistant to doxorubicin. Sci Rep 2015; 5:16538. [PMID: 26563869 PMCID: PMC4643312 DOI: 10.1038/srep16538] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 10/15/2015] [Indexed: 11/12/2022] Open
Abstract
Neoplastic cells accumulate magnesium, an event which provides selective advantages and is frequently associated with TRPM7 overexpression. Little is known about magnesium homeostasis in drug-resistant cancer cells. Therefore, we used the colon cancer LoVo cell model and compared doxorubicin-resistant to sensitive cells. In resistant cells the concentration of total magnesium is higher while its influx capacity is lower than in sensitive cells. Accordingly, resistant cells express lower amounts of the TRPM6 and 7, both involved in magnesium transport. While decreased TRPM6 levels are due to transcriptional regulation, post-transcriptional events are involved in reducing the amounts of TRPM7. Indeed, the calpain inhibitor calpeptin markedly increases the levels of TRPM7 in resistant cells. In doxorubicin-sensitive cells, silencing TRPM7 shifts the phenotype to one more similar to resistant cells, since in these cells silencing TRPM7 significantly decreases the influx of magnesium, increases its intracellular concentration and increases resistance to doxorubicin. On the other hand, calpain inhibition upregulates TRPM7, decreases intracellular magnesium and enhances the sensitivity to doxorubicin of resistant LoVo cells. We conclude that in LoVo cells drug resistance is associated with alteration of magnesium homeostasis through modulation of TRPM7. Our data suggest that TRPM7 expression may be an additional undisclosed player in chemoresistance.
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Affiliation(s)
- Sara Castiglioni
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
| | - Alessandra Cazzaniga
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
| | - Valentina Trapani
- Istituto di Patologia Generale, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Largo F. Vito 1, Roma I-00168
| | - Concettina Cappadone
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
| | - Giovanna Farruggia
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
- Istituto Nazionale Biostrutture e Biosistemi, Viale delle Medaglie d’oro 305, Roma I-00136
| | - Lucia Merolle
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
| | - Federica I. Wolf
- Istituto di Patologia Generale, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Largo F. Vito 1, Roma I-00168
| | - Stefano Iotti
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
- Istituto Nazionale Biostrutture e Biosistemi, Viale delle Medaglie d’oro 305, Roma I-00136
| | - Jeanette A M Maier
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
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125
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Abstract
Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca(2+) from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca(2+) sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca(2+) from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca(2+) depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease.
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Affiliation(s)
- Murali Prakriya
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
| | - Richard S Lewis
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
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126
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Tomilin V, Mamenko M, Zaika O, Pochynyuk O. Role of renal TRP channels in physiology and pathology. Semin Immunopathol 2015; 38:371-83. [PMID: 26385481 DOI: 10.1007/s00281-015-0527-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/04/2015] [Indexed: 01/05/2023]
Abstract
Kidneys critically contribute to the maintenance of whole-body homeostasis by governing water and electrolyte balance, controlling extracellular fluid volume, plasma osmolality, and blood pressure. Renal function is regulated by numerous systemic endocrine and local mechanical stimuli. Kidneys possess a complex network of membrane receptors, transporters, and ion channels which allows responding to this wide array of signaling inputs in an integrative manner. Transient receptor potential (TRP) channel family members with diverse modes of activation, varied permeation properties, and capability to integrate multiple downstream signals are pivotal molecular determinants of renal function all along the nephron. This review summarizes experimental data on the role of TRP channels in a healthy mammalian kidney and discusses their involvement in renal pathologies.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.,Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Mykola Mamenko
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.
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127
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Zhang Z, Faouzi M, Huang J, Geerts D, Yu H, Fleig A, Penner R. N-Myc-induced up-regulation of TRPM6/TRPM7 channels promotes neuroblastoma cell proliferation. Oncotarget 2015; 5:7625-34. [PMID: 25277194 PMCID: PMC4202149 DOI: 10.18632/oncotarget.2283] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Intracellular levels of the divalent cations Ca2+ and Mg2+ are important regulators of cell cycle and proliferation. However, the precise mechanisms by which they are regulated in cancer remain incompletely understood. The channel kinases TRPM6 and TRPM7 are gatekeepers of human Ca2+/Mg2+ metabolism. Here, we investigated the human neuroblastoma cell line SHEP-21N in which the MYCN oncogene (encoding N-Myc) can be reversibly expressed under control of an inducible repressor. We report that N-Myc expression increases cell growth and up-regulates both TRPM6 and TRPM7 expression. Membrane current analyses reveal that endogenous TRPM6/TRPM7 currents exhibit reduced Mg·ATP suppression, increased Mg2+ sensitivity, and diminished sensitivity to 2-APB inhibition. These properties are consistent with N-Myc-induced increase of heteromeric TRPM7/TRPM6 channels promoting Ca2+ and Mg2+ uptake. Genetic suppression of TRPM6/TRPM7 through siRNA inhibits cell proliferation, suggesting that N-Myc can promote neuroblastoma cell proliferation through up-regulation of divalent cation-transporting channels.
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Affiliation(s)
- Zheng Zhang
- Center for Biomedical Research, The Queen's Medical Center, University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A. Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China. Contributed equally to this work
| | - Malika Faouzi
- Center for Biomedical Research, The Queen's Medical Center, University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A.. Contributed equally to this work
| | - Junhao Huang
- Center for Biomedical Research, The Queen's Medical Center, University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Dr. Molewaterplein 50, GE Rotterdam, the Netherlands
| | - Haijie Yu
- Center for Biomedical Research, The Queen's Medical Center, University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A
| | - Andrea Fleig
- Center for Biomedical Research, The Queen's Medical Center,University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A
| | - Reinhold Penner
- Center for Biomedical Research, The Queen's Medical Center, University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, U.S.A
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128
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Abstract
Calcium (Ca2+) and magnesium (Mg2+) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca2+ and Mg2+ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca2+ and Mg2+; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.
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Affiliation(s)
- Yuyang Sun
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Pramod Sukumaran
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Anne Schaar
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Brij B Singh
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
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129
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Blanchard MG, Kittikulsuth W, Nair AV, de Baaij JHF, Latta F, Genzen JR, Kohan DE, Bindels RJM, Hoenderop JGJ. Regulation of Mg2+ Reabsorption and Transient Receptor Potential Melastatin Type 6 Activity by cAMP Signaling. J Am Soc Nephrol 2015; 27:804-13. [PMID: 26150606 DOI: 10.1681/asn.2014121228] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 05/21/2015] [Indexed: 01/14/2023] Open
Abstract
The transient receptor potential melastatin type 6 (TRPM6) epithelial Mg(2+) channels participate in transcellular Mg(2+) transport in the kidney and intestine. Previous reports suggested a hormonal cAMP-dependent regulation of Mg(2+) reabsorption in the kidney. The molecular details of this process are, however, unknown. Adenylate cyclase 3 (Adcy3) has been shown to colocalize with the Na(+)/Cl(-) cotransporter, a marker of the distal convoluted segment of the kidney, the principal site of TRPM6 expression. Given the critical role of TRPM6 in Mg(2+) reabsorption, an inducible kidney-specific Adcy3 deletion mouse model was characterized for blood and urinary electrolyte disturbances under a normal--and low--Mg(2+) diet. Increased urinary Mg(2+) wasting and Trpm6 mRNA levels were observed in the urine and kidney of Adcy3-deleted animals compared with wild-type controls. Serum Mg(2+) concentration was significantly lower in Adcy3-deleted animals at day 7 on the low Mg(2+) diet. Using patch clamp electrophysiology, cell surface biotinylation, and total internal reflection fluorescence live cell imaging of transfected HEK293 cells, we demonstrated that cAMP signaling rapidly potentiates TRPM6 activity by promoting TRPM6 accumulation at the plasma membrane and increasing its single-channel conductance. Comparison of electrophysiological data from cells expressing the phosphorylation-deficient S1252A or phosphomimetic S1252D TRPM6 mutants suggests that phosphorylation at this intracellular residue participates in the observed stimulation of channel activity. Altogether, these data support a physiologically relevant magnesiotropic role of cAMP signaling in the kidney by a direct stimulatory action of protein kinase A on the plasma membrane trafficking and function of TRPM6 ion channels.
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Affiliation(s)
- Maxime G Blanchard
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Anil V Nair
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Femke Latta
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jonathan R Genzen
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah; and
| | | | - René J M Bindels
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
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130
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Inhibition of TRPM7 Attenuates Rat Aortic Smooth Muscle Cell Proliferation Induced by Angiotensin II. J Cardiovasc Pharmacol 2015; 66:16-24. [DOI: 10.1097/fjc.0000000000000238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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131
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Vaeth M, Zee I, Concepcion AR, Maus M, Shaw P, Portal-Celhay C, Zahra A, Kozhaya L, Weidinger C, Philips J, Unutmaz D, Feske S. Ca2+ Signaling but Not Store-Operated Ca2+ Entry Is Required for the Function of Macrophages and Dendritic Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:1202-17. [PMID: 26109647 DOI: 10.4049/jimmunol.1403013] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 05/26/2015] [Indexed: 01/12/2023]
Abstract
Store-operated Ca(2+) entry (SOCE) through Ca(2+) release-activated Ca(2+) (CRAC) channels is essential for immunity to infection. CRAC channels are formed by ORAI1 proteins in the plasma membrane and activated by stromal interaction molecule (STIM)1 and STIM2 in the endoplasmic reticulum. Mutations in ORAI1 and STIM1 genes that abolish SOCE cause severe immunodeficiency with recurrent infections due to impaired T cell function. SOCE has also been observed in cells of the innate immune system such as macrophages and dendritic cells (DCs) and may provide Ca(2+) signals required for their function. The specific role of SOCE in macrophage and DC function, as well as its contribution to innate immunity, however, is not well defined. We found that nonselective inhibition of Ca(2+) signaling strongly impairs many effector functions of bone marrow-derived macrophages and bone marrow-derived DCs, including phagocytosis, inflammasome activation, and priming of T cells. Surprisingly, however, macrophages and DCs from mice with conditional deletion of Stim1 and Stim2 genes, and therefore complete inhibition of SOCE, showed no major functional defects. Their differentiation, FcR-dependent and -independent phagocytosis, phagolysosome fusion, cytokine production, NLRP3 inflammasome activation, and their ability to present Ags to activate T cells were preserved. Our findings demonstrate that STIM1, STIM2, and SOCE are dispensable for many critical effector functions of macrophages and DCs, which has important implications for CRAC channel inhibition as a therapeutic strategy to suppress pathogenic T cells while not interfering with myeloid cell functions required for innate immunity.
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Affiliation(s)
- Martin Vaeth
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Isabelle Zee
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Mate Maus
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Patrick Shaw
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | | | - Aleena Zahra
- Department of Medicine, New York University School of Medicine, New York, NY 10016
| | - Lina Kozhaya
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and Department of Medicine, New York University School of Medicine, New York, NY 10016
| | - Carl Weidinger
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Jennifer Philips
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
| | - Derya Unutmaz
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and Department of Medicine, New York University School of Medicine, New York, NY 10016
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and
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132
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Regulation of magnesium balance: lessons learned from human genetic disease. Clin Kidney J 2015; 5:i15-i24. [PMID: 26069817 PMCID: PMC4455826 DOI: 10.1093/ndtplus/sfr164] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Magnesium (Mg(2+)) is the fourth most abundant cation in the body. Thus, magnesium homeostasis needs to be tightly regulated, and this is facilitated by intestinal absorption and renal excretion. Magnesium absorption is dependent on two concomitant pathways found in both in the intestine and the kidneys: passive paracellular transport via claudins facilitates bulk magnesium absorption, whereas active transcellular pathways mediate the fine-tuning of magnesium absorption. The identification of genes responsible for diseases associated with hypomagnesaemia resulted in the discovery of several magnesiotropic proteins. Claudins 16 and 19 form the tight junction pore necessary for mass magnesium transport. However, most of the causes of genetic hypomagnesaemia can be tracked down to transcellular magnesium transport in the distal convoluted tubule. Within the distal convoluted tubule, magnesium reabsorption is a tightly regulated process that determines the final urine magnesium concentration. Therefore, insufficient magnesium transport in the distal convoluted tubule owing to mutated magnesiotropic proteins inevitably leads to magnesium loss, which cannot be compensated for in downstream tubule segments. Better understanding of the molecular mechanism regulating magnesium reabsorption will give new opportunities for better therapies, perhaps including therapies for patients with chronic renal failure.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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133
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Earley S, Brayden JE. Transient receptor potential channels in the vasculature. Physiol Rev 2015; 95:645-90. [PMID: 25834234 DOI: 10.1152/physrev.00026.2014] [Citation(s) in RCA: 302] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca(2+) levels or subcellular Ca(2+) signaling events. In addition to directly mediating Ca(2+) entry, TRP channels influence intracellular Ca(2+) dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions.
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Affiliation(s)
- Scott Earley
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| | - Joseph E Brayden
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
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134
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Isman E, Aras MH, Cengiz B, Bayraktar R, Yolcu U, Topcuoglu T, Usumez A, Demir T. Effects of laser irradiation at different wavelengths (660, 810, 980, and 1064 nm) on transient receptor potential melastatin channels in an animal model of wound healing. Lasers Med Sci 2015; 30:1489-95. [PMID: 25863514 DOI: 10.1007/s10103-015-1750-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/30/2015] [Indexed: 11/26/2022]
Abstract
The aim of the present study was to compare the effectiveness of four different laser wavelengths used for low-level laser therapy(LLLT) on healing of mucositis in an animal model of wound healing, by investigating expression of transient receptor potential melastatin(TRPM) ion channels. Forty-five rats were intraperitoneally injected with 100 mg/kg 5-fluorouracil on day 1 and 65 mg/kg on day 3. Superficial scratching on left cheek pouch mucosa was performed on days 3 and 5. After ulcerative mucositis was clinically detected, LLLT was started (660 nm, HELBO; 810 nm, Fotona-XD; 980 nm, ARC-Fox; and 1064 nm, Fidelis-Plus3) at 8 J/cm(2)/day from days 1 to 4. Oval excisional biopsy was performed at the wound site, and expression of TRPM2 to TRPM8 was evaluated. Student's t test was used for evaluation of significance of TRPM gene expression according to "0" value (α = 0.05). In 980-nm group, TRPM4, TRPM6, and TRPM7 were significantly higher than in the control group (p < 0.005). In 660, 810, and 1064 nm groups, only TRPM6 was significantly higher than in control group (p < 0.005). There were no significant differences between control and sham groups (p > 0.05). These findings suggest that expression of TRPM6 gene was significantly affected by irradiation with lasers at different wavelengths, whereas the TRPM4 and TRPM7 genes were only expressed in the 980-nm diode laser group. TRPM6 gene was highly expressed during LLLT, which may lead to accelerated wound healing and tissue repair. In contrast, there was some evidence that the 980-nm diode laser caused increased expression of TRPM4, TRPM6, and TRPM7 which are responsible for stimulation of Ca(2+) and Mg(2+) metabolism, as well as apoptotic pathways of controlled cell death.
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Affiliation(s)
- Eren Isman
- Department of Orthodontics, Faculty of Dentistry, Gaziantep University, Gaziantep, 27310, Turkey,
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135
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Effects of angiotensin II on transient receptor potential melastatin 7 channel function in cardiac fibroblasts. Exp Ther Med 2015; 9:2008-2012. [PMID: 26136930 DOI: 10.3892/etm.2015.2362] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 02/19/2015] [Indexed: 01/15/2023] Open
Abstract
The aim of the present study was to investigate the electrophysiological properties of transient receptor potential melastatin 7 (TRPM7) channels in the cell membranes of cardiac fibroblasts (CFs). CFs obtained from Sprague-Dawley rats were treated with six different concentrations of angiotensin (Ang) II for 12 h. The optimum concentration of Ang II for inducing fibrosis was selected by measuring collagen protein expression levels at each concentration. The optimum concentration of Ang II was then used to treat the CFs at five different time-points, and the TRPM7 current across the CF membranes was recorded along with the collagen protein levels in each group. The optimum Ang II concentration for inducing fibrosis was found to be 1 nmol/l; when it was administered to CFs at 0, 6, 12, 24 and 48 h, the protein expression levels of TRPM7 and collagen III initially increased, reaching maximum levels at 12 h, and then decreased. This result positively correlated with the TRPM7 current levels on either side of the CF membranes: The TRPM7 current under the effect of the optimal Ang II concentration for inducing fibrosis was initially increased and then later decreased. This is one of the key mechanisms by which Ang II mediates the proliferation and apoptosis of CFs. This knowledge may be used to identify treatments for the prevention of cardiac fibrosis.
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136
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Li C, Meng L, Li X, Li D, Jiang LH. Non-NMDAR neuronal Ca2+–permeable channels in delayed neuronal death and as potential therapeutic targets for ischemic brain damage. Expert Opin Ther Targets 2015; 19:879-92. [DOI: 10.1517/14728222.2015.1021781] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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137
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev 2015; 95:1-46. [PMID: 25540137 DOI: 10.1152/physrev.00012.2014] [Citation(s) in RCA: 886] [Impact Index Per Article: 98.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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138
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Abstract
PURPOSE OF REVIEW The tight control of blood magnesium (Mg) levels is of central importance for numerous physiological processes. A persistent low Mg status (hypomagnesemia) is associated with severe health risks and is involved in the pathogenesis of type 2 diabetes mellitus, osteoporosis, asthma, and heart and vascular diseases. The current view has expanded significantly as a result of the identification of novel genes and regulatory pathways involved in hypomagnesemic disorders. This review aims to give an up-to-date overview of transient receptor potential melastatin 6 (TRPM6) regulation and its role in the maintenance of Mg homeostasis. RECENT FINDINGS The epithelial Mg channel TRPM6 is considered to be the Mg entry pathway in the distal convoluted tubule of the kidney, where it functions as gatekeeper for controlling the body's Mg balance. Various factors and hormones contribute not only to the function, but also to the dysregulation of TRPM6, which has a substantial impact on renal Mg handling. Recent genetic and molecular studies have further elucidated the signaling processes of epithelial Mg transport, including their effect on the expression and function of TRPM6. SUMMARY Knowledge of TRPM6 functioning is of vital importance to decipher its role in Mg handling and will, in particular, provide a molecular basis for achieving a better understanding of Mg mal(re)absorption and hence systemic Mg balance.
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139
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Differential mRNA expression and glucocorticoid-mediated regulation of TRPM6 and TRPM7 in the heart and kidney throughout murine pregnancy and development. PLoS One 2015; 10:e0117978. [PMID: 25692682 PMCID: PMC4333289 DOI: 10.1371/journal.pone.0117978] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022] Open
Abstract
The transient receptor potential (TRP) channels TRPM6 and TRPM7 are critically involved in maintaining whole body and cellular Mg2+ homeostasis and ensuring the normal function of organs such as the heart and kidney. However, we do not know how the expression of TRPM6 and TPRM7 in these organs changes throughout fetal development and adult life, and whether this expression can be hormonally regulated. This study determined the ontogeny of TRPM6 and TRPM7 mRNA expression from mid-gestation through to adulthood in the mouse. In a second series of experiments, we examined how maternal administration of the glucocorticoids corticosterone and dexamethasone between embryonic days 12.5–15 affected TRPM6 and TRPM7 channel mRNA expression in the mother and fetus. Whilst renal TRPM7 expression was relatively constant throughout development, renal TRPM6 expression was markedly upregulated after birth. In contrast, cardiac TRPM7 expression was 2–4 fold higher in the fetus than in the adult. Surprisingly, TRPM6 expression was detected in the fetal heart (qPCR and in situ hybridization). Glucocorticoid administration during gestation increased fetal cardiac expression of both channels without affecting renal expression. In contrast, in the dam renal TRPM6 and TRPM7 expression was increased by glucocorticoids with no change in the cardiac channel expression. These data suggest that TRPM6 and TRPM7 channels are important in organogenesis, and that elevated maternal glucocorticoid levels can alter the expression of these channels. This suggests that perturbations in hormonal regulatory systems during pregnancy may adversely impact upon normal fetal development, at least in part by altering expression of TRPM channels.
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Yue Z, Xie J, Yu AS, Stock J, Du J, Yue L. Role of TRP channels in the cardiovascular system. Am J Physiol Heart Circ Physiol 2015; 308:H157-82. [PMID: 25416190 PMCID: PMC4312948 DOI: 10.1152/ajpheart.00457.2014] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/14/2014] [Indexed: 12/12/2022]
Abstract
The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases.
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Affiliation(s)
- Zhichao Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jia Xie
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Albert S Yu
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jonathan Stock
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jianyang Du
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Lixia Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
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141
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Nucleotide binding triggers a conformational change of the CBS module of the magnesium transporter CNNM2 from a twisted towards a flat structure. Biochem J 2015; 464:23-34. [PMID: 25184538 DOI: 10.1042/bj20140409] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Recent studies suggest CNNM2 (cyclin M2) to be part of the long-sought basolateral Mg2+ extruder at the renal distal convoluted tubule, or its regulator. In the present study, we explore structural features and ligand-binding capacities of the Bateman module of CNNM2 (residues 429-584), an intracellular domain structurally equivalent to the region involved in Mg2+ handling by the bacterial Mg2+ transporter MgtE, and AMP binding by the Mg2+ efflux protein CorC. Additionally, we studied the structural impact of the pathogenic mutation T568I located in this region. Our crystal structures reveal that nucleotides such as AMP, ADP or ATP bind at only one of the two cavities present in CNNM2429-584. Mg2+ favours ATP binding by alleviating the otherwise negative charge repulsion existing between acidic residues and the polyphosphate group of ATP. In crystals CNNM2429-584 forms parallel dimers, commonly referred to as CBS (cystathionine β-synthase) modules. Interestingly, nucleotide binding triggers a conformational change in the CBS module from a twisted towards a flat disc-like structure that mostly affects the structural elements connecting the Bateman module with the transmembrane region. We furthermore show that the T568I mutation, which causes dominant hypomagnesaemia, mimics the structural effect induced by nucleotide binding. The results of the present study suggest that the T568I mutation exerts its pathogenic effect in humans by constraining the conformational equilibrium of the CBS module of CNNM2, which becomes 'locked' in its flat form.
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142
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Hoffman NE, Miller BA, Wang J, Elrod JW, Rajan S, Gao E, Song J, Zhang XQ, Hirschler-Laszkiewicz I, Shanmughapriya S, Koch WJ, Feldman AM, Madesh M, Cheung JY. Ca²⁺ entry via Trpm2 is essential for cardiac myocyte bioenergetics maintenance. Am J Physiol Heart Circ Physiol 2015; 308:H637-50. [PMID: 25576627 DOI: 10.1152/ajpheart.00720.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ubiquitously expressed Trpm2 channel limits oxidative stress and preserves mitochondrial function. We first demonstrated that intracellular Ca(2+) concentration increase after Trpm2 activation was due to direct Ca(2+) influx and not indirectly via reverse Na(+)/Ca(2+) exchange. To elucidate whether Ca(2+) entry via Trpm2 is required to maintain cellular bioenergetics, we injected adenovirus expressing green fluorescent protein (GFP), wild-type (WT) Trpm2, and loss-of-function (E960D) Trpm2 mutant into left ventricles of global Trpm2 knockout (gKO) or WT hearts. Five days post-injection, gKO-GFP heart slices had higher reactive oxygen species (ROS) levels but lower oxygen consumption rate (OCR) than WT-GFP heart slices. Trpm2 but not E960D decreased ROS and restored OCR in gKO hearts back to normal levels. In gKO myocytes expressing Trpm2 or its mutants, Trpm2 but not E960D reduced the elevated mitochondrial superoxide (O2(.-)) levels in gKO myocytes. After hypoxia-reoxygenation (H/R), Trpm2 but not E906D or P1018L (inactivates Trpm2 current) lowered O2(.-) levels in gKO myocytes and only in the presence of extracellular Ca(2+), indicating sustained Ca(2+) entry is necessary for Trpm2-mediated preservation of mitochondrial function. After ischemic-reperfusion (I/R), cardiac-specific Trpm2 KO hearts exhibited lower maximal first time derivative of LV pressure rise (+dP/dt) than WT hearts in vivo. After doxorubicin treatment, Trpm2 KO mice had worse survival and lower +dP/dt. We conclude 1) cardiac Trpm2-mediated Ca(2+) influx is necessary to maintain mitochondrial function and protect against H/R injury; 2) Ca(2+) influx via cardiac Trpm2 confers protection against H/R and I/R injury by reducing mitochondrial oxidants; and 3) Trpm2 confers protection in doxorubicin cardiomyopathy.
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Affiliation(s)
- Nicholas E Hoffman
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania; Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - Barbara A Miller
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - JuFang Wang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - John W Elrod
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Sudasan Rajan
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania; Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - Erhe Gao
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jianliang Song
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Xue-Qian Zhang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | | | - Santhanam Shanmughapriya
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania; Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - Walter J Koch
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Arthur M Feldman
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Muniswamy Madesh
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania; Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - Joseph Y Cheung
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania; Division of Nephrology, Temple University School of Medicine, Philadelphia, Pennsylvania;
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143
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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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144
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Hill M, Dušková M, Stárka L. Dehydroepiandrosterone, its metabolites and ion channels. J Steroid Biochem Mol Biol 2015; 145:293-314. [PMID: 24846830 DOI: 10.1016/j.jsbmb.2014.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/06/2014] [Accepted: 05/11/2014] [Indexed: 11/20/2022]
Abstract
This review is focused on the physiological and pathophysiological relevance of steroids influencing the activities of the central and peripheral nervous systems with regard to their concentrations in body fluids and tissues in various stages of human life like the fetal development or pregnancy. The data summarized in this review shows that DHEA and its unconjugated and sulfated metabolites are physiologically and pathophysiologically relevant in modulating numerous ion channels and participate in vital functions of the human organism. DHEA and its unconjugated and sulfated metabolites including 5α/β-reduced androstane steroids participate in various physiological and pathophysiological processes like the management of GnRH cyclic release, regulation of glandular and neurotransmitter secretions, maintenance of glucose homeostasis on one hand and insulin insensitivity on the other hand, control of skeletal muscle and smooth muscle activities including vasoregulation, promotion of tolerance to ischemia and other neuroprotective effects. In respect of prevalence of steroid sulfates over unconjugated steroids in the periphery and the opposite situation in the CNS, the sulfated androgens and androgen metabolites reach relevance in peripheral organs. The unconjugated androgens and estrogens are relevant in periphery and so much the more in the CNS due to higher concentrations of most unconjugated steroids in the CNS tissues than in circulation and peripheral organs. This article is part of a Special Issue entitled "Essential role of DHEA".
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Affiliation(s)
- M Hill
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - M Dušková
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - L Stárka
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
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145
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Inoue K, O'Bryant Z, Xiong ZG. Zinc-permeable ion channels: effects on intracellular zinc dynamics and potential physiological/pathophysiological significance. Curr Med Chem 2015; 22:1248-57. [PMID: 25666796 PMCID: PMC4363167 DOI: 10.2174/0929867322666150209153750] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/14/2014] [Accepted: 02/02/2015] [Indexed: 02/08/2023]
Abstract
Zinc (Zn(2+)) is one of the most important trace metals in the body. It is necessary for the normal function of a large number of protein s including enzymes and transcription factors. While extracellular fluid may contain up to micromolar Zn(2+), intracellular Zn(2+) concentration is generally maintained at a subnanomolar level; this steep gradient across the cell membrane is primarily attributable to Zn(2+) extrusion by Zn(2+) transporting systems. Interestingly, systematic investigation has revealed that activities, previously believed to be dependent on calcium (Ca(2+)), may be partially mediated by Zn(2+). This is also supported by new findings that some Ca(2+)-permeable channels such as voltage-dependent calcium channels (VDCCs), N-methyl-D-aspartate receptors (NMDA), and amino-3- hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPA-Rs) are also permeable to Zn(2+). Thus, the importance of Zn(2+) in physiological and pathophysiological processes is now more widely appreciated. In this review, we describe Zn(2+)- permeable membrane molecules, especially Zn(2+)-permeable ion channels, in intracellular Zn(2+)dynamics and Zn(2+) mediated physiology/pathophysiology.
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Affiliation(s)
- Koichi Inoue
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, USA.
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146
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Elucidating the role of the TRPM7 alpha-kinase: TRPM7 kinase inactivation leads to magnesium deprivation resistance phenotype in mice. Sci Rep 2014; 4:7599. [PMID: 25534891 PMCID: PMC4274504 DOI: 10.1038/srep07599] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022] Open
Abstract
TRPM7 is an unusual bi-functional protein containing an ion channel covalently linked to a protein kinase domain. TRPM7 is implicated in regulating cellular and systemic magnesium homeostasis. While the biophysical properties of TRPM7 ion channel and its function are relatively well characterized, the function of the TRPM7 enzymatically active kinase domain is not understood yet. To investigate the physiological role of TRPM7 kinase activity, we constructed mice carrying an inactive TRPM7 kinase. We found that these mice were resistant to dietary magnesium deprivation, surviving three times longer than wild type mice; also they displayed decreased chemically induced allergic reaction. Interestingly, mutant mice have lower magnesium bone content compared to wild type mice when fed regular diet; unlike wild type mice, mutant mice placed on magnesium-depleted diet did not alter their bone magnesium content. Furthermore, mouse embryonic fibroblasts isolated from TRPM7 kinase-dead animals exhibited increased resistance to magnesium deprivation and oxidative stress. Finally, electrophysiological data revealed that the activity of the kinase-dead TRPM7 channel was not significantly altered. Together, our results suggest that TRPM7 kinase is a sensor of magnesium status and provides coordination of cellular and systemic responses to magnesium deprivation.
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147
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Turlova E, Bae CYJ, Deurloo M, Chen W, Barszczyk A, Horgen FD, Fleig A, Feng ZP, Sun HS. TRPM7 Regulates Axonal Outgrowth and Maturation of Primary Hippocampal Neurons. Mol Neurobiol 2014; 53:595-610. [PMID: 25502295 DOI: 10.1007/s12035-014-9032-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/30/2014] [Indexed: 11/25/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a calcium-permeable divalent cation channel and mediates neuronal cell death under ischemic stresses. In this study, we investigated the contribution of TRPM7 to neuronal development in mouse primary hippocampal neurons. We demonstrated that TRPM7 channels are highly expressed in the tips of the growth cone. Either knockdown of TRPM7 with target-specific shRNA or blocking channel conductance by a specific blocker waixenicin A enhanced axonal outgrowth in culture. Blocking TRPM7 activity by waixenicin A reduced calcium influx and accelerated the polarization of the hippocampal neurons as characterized by the development of distinct axons and dendrites. Furthermore, TRPM7 coprecipitated and colocalized with F-actin and α-actinin-1 at the growth cone. We conclude that calcium influx through TRPM7 inhibits axonal outgrowth and maturation by regulating the F-actin and α-actinin-1 protein complex. Inhibition of TRPM7 channel promotes axonal outgrowth, suggesting its therapeutic potential in neurodegenerative disorders.
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Affiliation(s)
- Ekaterina Turlova
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Christine Y J Bae
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Marielle Deurloo
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Wenliang Chen
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Andrew Barszczyk
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - F David Horgen
- College of Natural and Computational Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen's Medical Center, Honolulu, HI, 96720, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, Honolulu, HI, 96720, USA
| | - Zhong-Ping Feng
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Hong-Shuo Sun
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Pharmacology & Toxicology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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148
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Natural and Synthetic Modulators of the TRPM7 Channel. Cells 2014; 3:1089-101. [PMID: 25437439 PMCID: PMC4276914 DOI: 10.3390/cells3041089] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 11/16/2022] Open
Abstract
Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bi-functional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in magnesium metabolism, cell motility, proliferation and differentiation. TRPM7 is associated with anoxic neuronal death, cardiac fibrosis and tumor progression highlighting TRPM7 as a new drug target. Recently, several laboratories have independently identified pharmacological compounds inhibiting or activating the TRPM7 channel. The recently found TRPM7 modulators were used as new experimental tools to unravel cellular functions of the TRPM7 channel. Here, we provide a concise overview of this emerging field.
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149
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Chen SJ, Hoffman NE, Shanmughapriya S, Bao L, Keefer K, Conrad K, Merali S, Takahashi Y, Abraham T, Hirschler-Laszkiewicz I, Wang J, Zhang XQ, Song J, Barrero C, Shi Y, Kawasawa YI, Bayerl M, Sun T, Barbour M, Wang HG, Madesh M, Cheung JY, Miller BA. A splice variant of the human ion channel TRPM2 modulates neuroblastoma tumor growth through hypoxia-inducible factor (HIF)-1/2α. J Biol Chem 2014; 289:36284-302. [PMID: 25391657 DOI: 10.1074/jbc.m114.620922] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The calcium-permeable ion channel TRPM2 is highly expressed in a number of cancers. In neuroblastoma, full-length TRPM2 (TRPM2-L) protected cells from moderate oxidative stress through increased levels of forkhead box transcription factor 3a (FOXO3a) and superoxide dismutase 2. Cells expressing the dominant negative short isoform (TRPM2-S) had reduced FOXO3a and superoxide dismutase 2 levels, reduced calcium influx in response to oxidative stress, and enhanced reactive oxygen species, leading to decreased cell viability. Here, in xenografts generated with SH-SY5Y neuroblastoma cells stably expressing TRPM2 isoforms, growth of tumors expressing TRPM2-S was significantly reduced compared with tumors expressing TRPM2-L. Expression of hypoxia-inducible factor (HIF)-1/2α was significantly reduced in TRPM2-S-expressing tumor cells as was expression of target proteins regulated by HIF-1/2α including those involved in glycolysis (lactate dehydrogenase A and enolase 2), oxidant stress (FOXO3a), angiogenesis (VEGF), mitophagy and mitochondrial function (BNIP3 and NDUFA4L2), and mitochondrial electron transport chain activity (cytochrome oxidase 4.1/4.2 in complex IV). The reduction in HIF-1/2α was mediated through both significantly reduced HIF-1/2α mRNA levels and increased levels of von Hippel-Lindau E3 ligase in TRPM2-S-expressing cells. Inhibition of TRPM2-L by pretreatment with clotrimazole or expression of TRPM2-S significantly increased sensitivity of cells to doxorubicin. Reduced survival of TRPM2-S-expressing cells after doxorubicin treatment was rescued by gain of HIF-1 or -2α function. These data suggest that TRPM2 activity is important for tumor growth and for cell viability and survival following doxorubicin treatment and that interference with TRPM2-L function may be a novel approach to reduce tumor growth through modulation of HIF-1/2α, mitochondrial function, and mitophagy.
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Affiliation(s)
| | - Nicholas E Hoffman
- the Center for Translational Medicine and Departments of Biochemistry and
| | | | - Lei Bao
- From the Departments of Pediatrics
| | | | | | | | | | - Thomas Abraham
- Research Resources, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | | | | | | | | | | | | | - Yuka Imamura Kawasawa
- Pharmacology, Biochemistry and Molecular Biology, Institute for Personalized Medicine, and
| | | | | | | | | | - Muniswamy Madesh
- the Center for Translational Medicine and Departments of Biochemistry and
| | - Joseph Y Cheung
- the Center for Translational Medicine and Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Barbara A Miller
- From the Departments of Pediatrics, Biochemistry and Molecular Biology,
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150
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Tashiro M, Inoue H, Konishi M. Physiological pathway of magnesium influx in rat ventricular myocytes. Biophys J 2014; 107:2049-58. [PMID: 25418090 PMCID: PMC4223180 DOI: 10.1016/j.bpj.2014.09.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/03/2014] [Accepted: 09/16/2014] [Indexed: 11/16/2022] Open
Abstract
Cytoplasmic free Mg(2+) concentration ([Mg(2+)]i) was measured in rat ventricular myocytes with a fluorescent indicator furaptra (mag-fura-2) introduced by AM-loading. By incubation of the cells in a high-K(+) (Ca(2+)- and Mg(2+)-free) solution, [Mg(2+)]i decreased from ? 0.9 mM to 0.2 to 0.5 mM. The lowered [Mg(2+)]i was recovered by perfusion with Ca(2+)-free Tyrode's solution containing 1 mM Mg(2+). The time course of the [Mg(2+)]i recovery was fitted by a single exponential function, and the first derivative at time 0 was analyzed as being proportional to the initial Mg(2+) influx rate. The Mg(2+) influx rate was inversely related to [Mg(2+)]i, being higher at low [Mg(2+)]i. The Mg(2+) influx rate was augmented by the high extracellular Mg(2+) concentration (5 mM), whereas it was greatly reduced by cell membrane depolarization caused by high K(+). Known inhibitors of TRPM7 channels, 2-aminoethoxydiphenyl borate (2-APB), NS8593, and spermine reduced the Mg(2+) influx rate with half inhibitory concentrations (IC50) of, respectively, 17 ?M, 2.0 ?M, and 22 ?M. We also studied Ni(2+) influx by fluorescence quenching of intracellular furaptra by Ni(2+). The Ni(2+) influx was activated by lowering intra- and extracellular Mg(2+) concentrations, and it was inhibited by 2-APB and NS8593 with IC50 values comparable with those for the Mg(2+) influx. Intracellular alkalization (caused by pulse application of NH4Cl) enhanced, whereas intracellular acidification (induced after the removal of NH4Cl) slowed the Mg(2+) influx. Under the whole-cell patch-clamp configuration, the removal of intracellular and extracellular divalent cations induced large inward and outward currents, MIC (Mg-inhibited cation) currents or IMIC, carried by monovalent cations likely via TRPM7 channels. IMIC measured at -120 mV was diminished to ? 50% by 100 ?M 2-APB or 10 ?M NS8593. These results suggest that TRPM7/MIC channels serve as a major physiological pathway of Mg(2+) influx in rat ventricular myocytes.
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Affiliation(s)
- Michiko Tashiro
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan.
| | - Hana Inoue
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
| | - Masato Konishi
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
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