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Pharmacological Modulation and (Patho)Physiological Roles of TRPM4 Channel-Part 2: TRPM4 in Health and Disease. Pharmaceuticals (Basel) 2021; 15:ph15010040. [PMID: 35056097 PMCID: PMC8779181 DOI: 10.3390/ph15010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 02/06/2023] Open
Abstract
Transient receptor potential melastatin 4 (TRPM4) is a unique member of the TRPM protein family and, similarly to TRPM5, is Ca2+ sensitive and permeable for monovalent but not divalent cations. It is widely expressed in many organs and is involved in several functions; it regulates membrane potential and Ca2+ homeostasis in both excitable and non-excitable cells. This part of the review discusses the currently available knowledge about the physiological and pathophysiological roles of TRPM4 in various tissues. These include the physiological functions of TRPM4 in the cells of the Langerhans islets of the pancreas, in various immune functions, in the regulation of vascular tone, in respiratory and other neuronal activities, in chemosensation, and in renal and cardiac physiology. TRPM4 contributes to pathological conditions such as overactive bladder, endothelial dysfunction, various types of malignant diseases and central nervous system conditions including stroke and injuries as well as in cardiac conditions such as arrhythmias, hypertrophy, and ischemia-reperfusion injuries. TRPM4 claims more and more attention and is likely to be the topic of research in the future.
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Histamine-induced Ca²⁺ signalling is mediated by TRPM4 channels in human adipose-derived stem cells. Biochem J 2014; 463:123-34. [PMID: 25001294 DOI: 10.1042/bj20140065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Intracellular Ca2+ oscillations are frequently observed during stem cell differentiation, and there is evidence that it may control adipogenesis. The transient receptor potential melastatin 4 channel (TRPM4) is a key regulator of Ca2+ signals in excitable and non-excitable cells. However, its role in human adipose-derived stem cells (hASCs), in particular during adipogenesis, is unknown. We have investigated TRPM4 in hASCs and examined its impact on histamine-induced Ca2+ signalling and adipogenesis. Using reverse transcription (RT)-PCR, we have identified TRPM4 gene expression in hASCs and human adipose tissue. Electrophysiological recordings revealed currents with the characteristics of those reported for the channel. Furthermore, molecular suppression of TRPM4 with shRNA diminished the Ca2+ signals generated by histamine stimulation, mainly via histamine receptor 1 (H1) receptors. The increases in intracellular Ca2+ were due to influx via voltage-dependent Ca2+ channels (VDCCs) of the L-type (Ca(v)1.2) and release from the endoplasmic reticulum. Inhibition of TRPM4 by shRNA inhibited adipogenesis as indicated by the reduction in lipid droplet accumulation and adipocyte gene expression. These results suggest that TRPM4 is an important regulator of Ca2+ signals generated by histamine in hASCs and is required for adipogenesis.
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Abstract
TRPM4 is a Ca(2+)-activated nonselective cation channel. The channel is activated by an increase of intracellular Ca(2+) and is regulated by several factors including temperature and Pi(4,5)P2. TRPM4 allows Na(+) entry into the cell upon activation, but is completely impermeable to Ca(2+). Unlike TRPM5, its closest relative in the transient receptor potential family, TRPM4 proteins are widely expressed in the body. Currents with properties that are reminiscent of TRPM4 have been described in a variety of tissues since the advent of the patch clamp technology, but their physiological role is only beginning to be clarified with the increasing characterization of knockout mouse models for TRPM4. Furthermore, mutations in the TRPM4 gene have been associated with cardiac conduction disorders in human patients. This review aims to overview the currently available data on the functional properties of TRPM4 and the current understanding of its physiological role in healthy and diseased tissue.
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Affiliation(s)
- Ilka Mathar
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Herestraat 49, bus 802, 3000, Leuven, Belgium
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The Ca2+-Activated Monovalent Cation-Selective Channels TRPM4 and TRPM5. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2012. [DOI: 10.1007/978-1-62703-077-9_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Abstract
In the current review we will summarise data from the recent literature describing molecular and functional properties of TRPM4. Together with TRPM5, these channels are up till now the only molecular candidates for a class of non-selective, Ca(2+)-impermeable cation channels which are activated by elevated Ca2+ levels in the cytosol. Apart from intracellular Ca2+, TRPM4 activation is also dependent on membrane potential. Additionally, channel activity is modulated by ATP, phosphatidylinositol bisphosphate (PiP2), protein kinase C (PKC) phosphorylation and heat. The molecular determinants for channel activation, permeation and modulation are increasingly being clarified, and will be discussed here in detail. The physiological role of Ca(2+)-activated non-selective cation channels is unclear, especially in the absence of gene-specific knock-out mice, but evidence indicates a role as a regulator of membrane potential, and thus the driving force for Ca2+ entry from the extracellular medium.
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Affiliation(s)
- R Vennekens
- Laboratory of Physiology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, Herestraat 49-Bus 802, 3000 Leuven, Belgium.
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Ullrich ND, Voets T, Prenen J, Vennekens R, Talavera K, Droogmans G, Nilius B. Comparison of functional properties of the Ca2+-activated cation channels TRPM4 and TRPM5 from mice. Cell Calcium 2005; 37:267-78. [PMID: 15670874 DOI: 10.1016/j.ceca.2004.11.001] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 10/29/2004] [Accepted: 11/03/2004] [Indexed: 11/26/2022]
Abstract
Non-selective cation (NSC) channels activated by intracellular Ca2+ ([Ca2+]i) play an important role in Ca2+ signaling and membrane excitability in many cell types. TRPM4 and TRPM5, two Ca2+-activated cation channels of the TRP superfamily, are potential molecular correlates of NSC channels. We compared the functional properties of mouse TRPM4 and TRPM5 heterologously expressed in HEK 293 cells. Dialyzing cells with different Ca2+ concentrations revealed a difference in Ca2+ sensitivity between TRPM4 and TRPM5, with EC50 values of 20.2+/-4.0 microM and 0.70+/-0.1 microM, respectively. Similarly, TRPM5 activated at lower Ca2+ concentration than TRPM4 when [Ca2+]i was raised by UV uncaging of the Ca2+-cage DMNP-EDTA. Current amplitudes of TRPM4 and TRPM5 were not correlated to the rate of changes in [Ca2+]i. The Ca2+ sensitivity of both channels was strongly reduced in inside-out patches, resulting in approximately 10-30 times higher EC50 values than under whole-cell conditions. Currents through TRPM4 and TRPM5 deactivated at negative and activated at positive potentials with similar kinetics. Both channels were equally sensitive to block by intracellular spermine. TRPM4 displayed a 10-fold higher affinity for block by flufenamic acid. Importantly, ATP4- blocked TRPM4 with high affinity (IC50 of 0.8+/-0.1 microM), whereas TRPM5 is insensitive to ATP4- at concentrations up to 1 mM.
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Affiliation(s)
- Nina D Ullrich
- Laboratorium voor Fysiologie, Department of Physiology, Campus Gasthuisberg, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Csanády L, Adam-Vizi V. Antagonistic regulation of native Ca2+- and ATP-sensitive cation channels in brain capillaries by nucleotides and decavanadate. ACTA ACUST UNITED AC 2005; 123:743-57. [PMID: 15173222 PMCID: PMC2234573 DOI: 10.1085/jgp.200309008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Regulation by cytosolic nucleotides of Ca2+- and ATP-sensitive nonselective cation channels (CA-NSCs) in rat brain capillary endothelial cells was studied in excised inside-out patches. Open probability (Po) was suppressed by cytosolic nucleotides with apparent KI values of 17, 9, and 2 μM for ATP, ADP, and AMP, as a consequence of high-affinity inhibition of channel opening rate and low-affinity stimulation of closing rate. Cytosolic [Ca2+] and voltage affected inhibition of Po, but not of opening rate, by ATP, suggesting that the conformation of the nucleotide binding site is influenced only by the state of the channel gate, not by that of the Ca2+ and voltage sensors. ATP inhibition was unaltered by channel rundown. Nucleotide structure affected inhibitory potency that was little sensitive to base substitutions, but was greatly diminished by 3′-5′ cyclization, removal of all phosphates, or complete omission of the base. In contrast, decavanadate potently (K1/2 = 90 nM) and robustly stimulated Po, and functionally competed with inhibitory nucleotides. From kinetic analyses we conclude that (a) ATP, ADP, and AMP bind to a common site; (b) inhibition by nucleotides occurs through simple reversible binding, as a consequence of tighter binding to the closed-channel relative to the open-channel conformation; (c) the conformation of the nucleotide binding site is not directly modulated by Ca2+ and voltage; (d) the differences in inhibitory potency of ATP, ADP, and AMP reflect their different affinities for the closed channel; and (e) though decavanadate is the only example found to date of a compound that stimulates Po with high affinity even in the presence of millimolar nucleotides, apparently by competing for the nucleotide binding site, a comparable mechanism might allow CA-NSC channels to open in living cells despite physiological levels of nucleotides. Decavanadate now provides a valuable tool for studying native CA-NSC channels and for screening cloned channels.
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Affiliation(s)
- László Csanády
- Department of Medical Biochemistry, Semmelweis University, and Neurochemical Group of the Hungarian Academy of Sciences, Budapest, Hungary.
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Nilius B, Prenen J, Janssens A, Voets T, Droogmans G. Decavanadate modulates gating of TRPM4 cation channels. J Physiol 2004; 560:753-65. [PMID: 15331675 PMCID: PMC1665285 DOI: 10.1113/jphysiol.2004.070839] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have tested the effects of decavanadate (DV), a compound known to interfere with ATP binding in ATP-dependent transport proteins, on TRPM4, a Ca(2+)-activated, voltage-dependent monovalent cation channel, whose activity is potently blocked by intracellular ATP(4-). Application of micromolar Ca(2+) concentrations to the cytoplasmic side of inside-out patches led to immediate current activation followed by rapid current decay, which can be explained by an at least 30-fold decreased apparent affinity for Ca(2+). Subsequent application of DV (10 microm) strongly affected the voltage-dependent gating of the channel, resulting in large sustained currents over the voltage range between -180 and +140 mV. The effect of DV was half-maximal at a concentration of 1.9 microm. The Ca(2+)- and voltage-dependent gating of the channel was well described by a sequential kinetic scheme in which Ca(2+) binding precedes voltage-dependent gating. The effects of DV could be explained by an action on the voltage-dependent closing step. Surprisingly, DV did not antagonize the effect of ATP(4-) on TRPM4, but caused a nearly 10-fold increase in the sensitivity of the ATP(4-) block. TRPM5, which is the most homologous channel to TRPM4, was not modulated by DV. The effect of DV was lost in a TRPM4 chimera in which the C-terminus was substituted with that of TRPM5. Deletion of a cluster in the C-terminus of TRPM4 containing positively charged amino acid residues with a high homology to part of the decavanadate binding site in SERCA pumps, completely abolished the DV effect but also accelerated desensitization. Deletion of a similar site in the N-terminus had no effects on DV responses. These results indicate that the C-terminus of TRPM4 is critically involved in mediating the DV effects. In conclusion, decavanadate modulates TRPM4, but not TRPM5, by inhibiting voltage-dependent closure of the channel.
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Affiliation(s)
- Bernd Nilius
- Department of Physiology, Campus Gasthuisberg, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium.
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Mair N, Frick M, Bertocchi C, Haller T, Amberger A, Weiss H, Margreiter R, Streif W, Dietl P. Inhibition by cytoplasmic nucleotides of a new cation channel in freshly isolated human and rat type II pneumocytes. Am J Physiol Lung Cell Mol Physiol 2004; 287:L1284-92. [PMID: 15321785 DOI: 10.1152/ajplung.00177.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Here we report a 26- to 29-pS cation channel abundantly expressed in freshly isolated and primary cultured type II cells from rat or healthy human lungs. The channel was never spontaneously active in cell-attached patches but could be activated by cell permeabilization with beta-escin. Excised patch-clamp experiments revealed activation by Ca(2+) concentrations at the cytoplasmic side in the micromolar range. High concentrations of amiloride (>10 microM) at the extracellular side did not inhibit. The channel was equally permeable for K(+) and Na(+) but was essentially impermeable for Cl(-), Ca(2+), and Mg(2+). It was blocked by adenosine nucleotides (cytoplasmic side) with the following order of potency: AMP approximately ADP (EC(50) </= 10 microM) > ATP >> adenosine >> cyclic AMP. The blocking effect of ATP was reproduced by its nonhydrolyzable analogs AMPPNP or ATP-gamma-S. GTP did not inhibit. Cd(2+) blocked the channel with an EC(50) approximately 55.5 nM. We conclude that type II cells express a Ca(2+)-dependent, nucleotide-inhibited, nonselective, and Ca(2+)-impermeable cation channel (NSC(Ca/AMP)) with tonically suppressed activity. RT-PCR confirmed expression of TRPM4b, a channel with functional characteristics almost identical with NSC(Ca/AMP). Potential physiological roles are discussed.
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Affiliation(s)
- Norbert Mair
- Department of Physiology, Medical University of Innsbruck, Fritz-Pregl-Str. 3, A-6020 Innsbruck, Austria
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Nilius B, Prenen J, Voets T, Droogmans G. Intracellular nucleotides and polyamines inhibit the Ca2+-activated cation channel TRPM4b. Pflugers Arch 2004; 448:70-5. [PMID: 14758478 DOI: 10.1007/s00424-003-1221-x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Accepted: 11/28/2003] [Indexed: 02/05/2023]
Abstract
TRPM4b (in contrast to the short splice variant TRPM4a) is a Ca(2+)-activated but Ca(2+)-impermeable cation channel. We have studied TRPM4 currents in inside-out patches. Supramicromolar Ca(2+) concentrations applied at the inner side, [Ca(2+)](i), activated TRPM4 with an EC(50) value of 0.37 mM, a value that is much higher than that of whole-cell currents. Current amplitudes decreased above 1 mM [Ca(2+)](i), (IC(50) 9.3 mM). Sr(2+) but not Ba(2+)could partially substitute for Ca(2+). ATP, ADP, AMP and AMP-PNP all quickly and reversibly inhibited TRPM4 with IC(50) values between 2 and 19 microM (at +100 mV). Adenosine also blocked TRPM4 at 630 microM. The block at high ATP concentrations was incomplete and was not affected by the presence of free Mg(2+). ADP induced the most sensitive block with an IC(50) of 2.2 microM. For inhibition of TRPM4 by free ATP(4-), an IC(50) value of 1.7+/-0.3 microM was calculated. GTP, UTP and CTP at concentrations up to 1 mM did not induce a similar block. Spermine blocked TRPM4 currents with an IC(50) of 61 microM. In conclusion, TRPM4 is a channel that can be effectively modulated by intracellular nucleotides and polyamines.
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Affiliation(s)
- Bernd Nilius
- Laboratorium voor Fysiologie Campus Gasthuisberg, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
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Liang J, Wang FS, Liu YF, Liu LM, Liu SR, Cui H, Tai CQ, He SG. Intercellular adhesion molecule-1 expression in pancreas graft and its signal transducer. Shijie Huaren Xiaohua Zazhi 2003; 11:1396-1398. [DOI: 10.11569/wcjd.v11.i9.1396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the effect of neutrophil elastase inhibitor (ONO-5046) on expression of intercellular adhesion molecule-1 and transduction signal after pancreasduodenal transplantation in rats.
METHODS ONO-5 046 was injected intravenously into experimental animal models. ICAM-1 mRNA transduction signals were detected in rat endothelial cells with regard to the effect of many reagents on expression of ICAM.
RESULTS ICAM-1 mRNA level decreased in pancreatic grafts of experimental animals. ICAM-1 mRNA expression was increased in rat endothelial cells in vitro stimulated by NE, while that it could be inhibited by ONO-5046. Calcium ionophore enhenced ICAM-1 mRNA expression. In contrast, a phospholipase C inhibitor, calcium chelator and nuclear factor-kappa B inhibitor regulated down NE induction of ICAM-1 mRNA.
CONCLUSION ICAM-1 expression stimulated by NE in pancreatic grafts may be associated with intracellular Ca2+ influx and a phospholipase C signal transduction.
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Affiliation(s)
- Jian Liang
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Feng-Shan Wang
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Yong-Feng Liu
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Li-Min Liu
- Institute of Forensic Medicine, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Shu-Rong Liu
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Hong Cui
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - Chun-Quan Tai
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
| | - San-Guang He
- First Department of Surgery, First Affiliated Hospital, China Medical University, 110001 Shenyang, Liaoning Province, China
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