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Transient Receptor Potential (TRP) Channels in Tumor Vascularization. Int J Mol Sci 2022; 23:ijms232214253. [PMID: 36430727 PMCID: PMC9692925 DOI: 10.3390/ijms232214253] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
Tumor diseases are unfortunately quick spreading, even though numerous studies are under way to improve early diagnosis and targeted treatments that take into account both the different characteristics associated with the various tumor types and the conditions of individual patients. In recent years, studies have focused on the role of ion channels in tumor development, as these proteins are involved in several cellular processes relevant to neoplastic transformation. Among all ion channels, many studies have focused on the superfamily of Transient Receptor Potential (TRP) channels, which are non-selective cation channels mediating extracellular Ca2+ influx. In this review, we examined the role of different endothelial TRP channel isoforms in tumor vessel formation, a process that is essential in tumor growth and metastasis.
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Khattar V, Wang L, Peng JB. Calcium selective channel TRPV6: Structure, function, and implications in health and disease. Gene 2022; 817:146192. [PMID: 35031425 PMCID: PMC8950124 DOI: 10.1016/j.gene.2022.146192] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 12/14/2022]
Abstract
Calcium-selective channel TRPV6 (Transient Receptor Potential channel family, Vanilloid subfamily member 6) belongs to the TRP family of cation channels and plays critical roles in transcellular calcium (Ca2+) transport, reuptake of Ca2+ into cells, and maintaining a local low Ca2+ environment for certain biological processes. Recent crystal and cryo-electron microscopy-based structures of TRPV6 have revealed mechanistic insights on how the protein achieves Ca2+ selectivity, permeation, and inactivation by calmodulin. The TRPV6 protein is expressed in a range of epithelial tissues such as the intestine, kidney, placenta, epididymis, and exocrine glands such as the pancreas, prostate and salivary, sweat, and mammary glands. The TRPV6 gene is a direct transcriptional target of the active form of vitamin D and is efficiently regulated to meet the body's need for Ca2+ demand. In addition, TRPV6 is also regulated by the level of dietary Ca2+ and under physiological conditions such as pregnancy and lactation. Genetic models of loss of function in TRPV6 display hypercalciuria, decreased bone marrow density, deficient weight gain, reduced fertility, and in some cases alopecia. The models also reveal that the channel plays an indispensable role in maintaining maternal-fetal Ca2+ transport and low Ca2+ environment in the epididymal lumen that is critical for male fertility. Most recently, loss of function mutations in TRPV6 gene is linked to transient neonatal hyperparathyroidism and early onset chronic pancreatitis. TRPV6 is overexpressed in a wide range of human malignancies and its upregulation is strongly correlated to tumor aggressiveness, metastasis, and poor survival in selected cancers. This review summarizes the current state of knowledge on the expression, structure, biophysical properties, function, polymorphisms, and regulation of TRPV6. The aberrant expression, polymorphisms, and dysfunction of this protein linked to human diseases are also discussed.
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Affiliation(s)
- Vinayak Khattar
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Hu F, Cao X, Niu C, Wang K. Co-assembly of warm-temperature sensitive TRPV3 and TRPV4 channel complexes with distinct functional properties. Mol Pharmacol 2022; 101:390-399. [PMID: 35361697 DOI: 10.1124/molpharm.121.000370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 03/17/2022] [Indexed: 11/22/2022] Open
Abstract
Heteromeric assembly of temperature-sensitive TRP ion channels has been suggested to underlie the molecular basis of fine-tuning of temperature detection and chemical sensation. However, whether warmth-temperature sensitive TRPV3 and TRPV4 channels robustly expressed in the skin can form heteromeric assembly remains largely unknown. In this study, we show that TRPV3 and TRPV4 channels can co-assemble into functional heterotetrameric channels with distinct properties. Confocal imaging reveals a co-localization and association of TRPV3 and TRPV4 proteins in cell membrane. Co-immunoprecipitation analysis demonstrates a strong protein-protein interaction between TRPV3 and TRPV4 subunits from heterogeneously expressed cells or mouse skin tissues through their C-termini, but not in TRPV3 knockout tissues. Co-expression of TRPV3 and TRPV4 channels yields a heterotetrameric channel complexes characterized by an intermediate single-channel conductance, distinct activation threshold and pharmacology. Taken together, our findings demonstrate a heterotetrameric assembly of TRPV3 and TRPV4 channels, which may help explain the role of temperature-sensitive TRPV channels in fine-tuning of environmental detection and sensation in the skin. Significance Statement The co-assembly of TRPV3 and TRPV4 channel complexes increases the functional diversity within the channel subfamily, which may serve as a molecular basis for fine-tuning of environmental detection and temperature sensation in mammals.
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Distribution and Assembly of TRP Ion Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1349:111-138. [PMID: 35138613 DOI: 10.1007/978-981-16-4254-8_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the last several decades, a large family of ion channels have been identified and studied intensively as cellular sensors for diverse physical and/or chemical stimuli. Named transient receptor potential (TRP) channels, they play critical roles in various aspects of cellular physiology. A large number of human hereditary diseases are found to be linked to TRP channel mutations, and their dysregulations lead to acute or chronical health problems. As TRP channels are named and categorized mostly based on sequence homology rather than functional similarities, they exhibit substantial functional diversity. Rapid advances in TRP channel study have been made in recent years and reported in a vast body of literature; a summary of the latest advancements becomes necessary. This chapter offers an overview of current understandings of TRP channel distribution and subunit assembly.
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Zergane M, Kuebler WM, Michalick L. Heteromeric TRP Channels in Lung Inflammation. Cells 2021; 10:cells10071654. [PMID: 34359824 PMCID: PMC8307017 DOI: 10.3390/cells10071654] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/09/2021] [Accepted: 06/25/2021] [Indexed: 12/15/2022] Open
Abstract
Activation of Transient Receptor Potential (TRP) channels can disrupt endothelial barrier function, as their mediated Ca2+ influx activates the CaM (calmodulin)/MLCK (myosin light chain kinase)-signaling pathway, and thereby rearranges the cytoskeleton, increases endothelial permeability and thus can facilitate activation of inflammatory cells and formation of pulmonary edema. Interestingly, TRP channel subunits can build heterotetramers, whereas heteromeric TRPC1/4, TRPC3/6 and TRPV1/4 are expressed in the lung endothelium and could be targeted as a protective strategy to reduce endothelial permeability in pulmonary inflammation. An update on TRP heteromers and their role in lung inflammation will be provided with this review.
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Affiliation(s)
- Meryam Zergane
- Institute of Physiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (M.Z.); (L.M.)
| | - Wolfgang M. Kuebler
- Institute of Physiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (M.Z.); (L.M.)
- German Centre for Cardiovascular Research (DZHK), 10785 Berlin, Germany
- German Center for Lung Research (DZL), 35392 Gießen, Germany
- The Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada
- Department of Surgery and Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence:
| | - Laura Michalick
- Institute of Physiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (M.Z.); (L.M.)
- German Centre for Cardiovascular Research (DZHK), 10785 Berlin, Germany
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Negri S, Faris P, Rosti V, Antognazza MR, Lodola F, Moccia F. Endothelial TRPV1 as an Emerging Molecular Target to Promote Therapeutic Angiogenesis. Cells 2020; 9:cells9061341. [PMID: 32471282 PMCID: PMC7349285 DOI: 10.3390/cells9061341] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023] Open
Abstract
Therapeutic angiogenesis represents an emerging strategy to treat ischemic diseases by stimulating blood vessel growth to rescue local blood perfusion. Therefore, injured microvasculature may be repaired by stimulating resident endothelial cells or circulating endothelial colony forming cells (ECFCs) or by autologous cell-based therapy. Endothelial Ca2+ signals represent a crucial player in angiogenesis and vasculogenesis; indeed, several angiogenic stimuli induce neovessel formation through an increase in intracellular Ca2+ concentration. Several members of the Transient Receptor Potential (TRP) channel superfamily are expressed and mediate Ca2+-dependent functions in vascular endothelial cells and in ECFCs, the only known truly endothelial precursor. TRP Vanilloid 1 (TRPV1), a polymodal cation channel, is emerging as an important player in endothelial cell migration, proliferation, and tubulogenesis, through the integration of several chemical stimuli. Herein, we first summarize TRPV1 structure and gating mechanisms. Next, we illustrate the physiological roles of TRPV1 in vascular endothelium, focusing our attention on how endothelial TRPV1 promotes angiogenesis. In particular, we describe a recent strategy to stimulate TRPV1-mediated pro-angiogenic activity in ECFCs, in the presence of a photosensitive conjugated polymer. Taken together, these observations suggest that TRPV1 represents a useful target in the treatment of ischemic diseases.
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Affiliation(s)
- Sharon Negri
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (S.N.); (P.F.)
| | - Pawan Faris
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (S.N.); (P.F.)
| | - Vittorio Rosti
- Center for the Study of Myelofibrosis, Laboratory of Biochemistry, Biotechnology and Advanced Diagnosis, IRCCS Policlinico San Matteo Foundation, 27100 Pavia, Italy;
| | - Maria Rosa Antognazza
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, via Pascoli 70/3, 20133 Milano, Italy; (M.R.A.); (F.L.)
| | - Francesco Lodola
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, via Pascoli 70/3, 20133 Milano, Italy; (M.R.A.); (F.L.)
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (S.N.); (P.F.)
- Correspondence:
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Santoni G, Santoni M, Maggi F, Marinelli O, Morelli MB. Emerging Role of Mucolipins TRPML Channels in Cancer. Front Oncol 2020; 10:659. [PMID: 32411610 PMCID: PMC7198773 DOI: 10.3389/fonc.2020.00659] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/08/2020] [Indexed: 12/26/2022] Open
Affiliation(s)
- Giorgio Santoni
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Matteo Santoni
- Medical Oncology Unit, Hospital of Macerata, Macerata, Italy
| | - Federica Maggi
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, University of Rome Sapienza, Rome, Italy
| | - Oliviero Marinelli
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy.,School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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Nanoparticle-Mediated Therapeutic Application for Modulation of Lysosomal Ion Channels and Functions. Pharmaceutics 2020; 12:pharmaceutics12030217. [PMID: 32131531 PMCID: PMC7150957 DOI: 10.3390/pharmaceutics12030217] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 02/07/2023] Open
Abstract
Applications of nanoparticles in various fields have been addressed. Nanomaterials serve as carriers for transporting conventional drugs or proteins through lysosomes to various cellular targets. The basic function of lysosomes is to trigger degradation of proteins and lipids. Understanding of lysosomal functions is essential for enhancing the efficacy of nanoparticles-mediated therapy and reducing the malfunctions of cellular metabolism. The lysosomal function is modulated by the movement of ions through various ion channels. Thus, in this review, we have focused on the recruited ion channels for lysosomal function, to understand the lysosomal modulation through the nanoparticles and its applications. In the future, lysosomal channels-based targets will expand the therapeutic application of nanoparticles-associated drugs.
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Negri S, Faris P, Berra-Romani R, Guerra G, Moccia F. Endothelial Transient Receptor Potential Channels and Vascular Remodeling: Extracellular Ca 2 + Entry for Angiogenesis, Arteriogenesis and Vasculogenesis. Front Physiol 2020; 10:1618. [PMID: 32038296 PMCID: PMC6985578 DOI: 10.3389/fphys.2019.01618] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022] Open
Abstract
Vasculogenesis, angiogenesis and arteriogenesis represent three crucial mechanisms involved in the formation and maintenance of the vascular network in embryonal and post-natal life. It has long been known that endothelial Ca2+ signals are key players in vascular remodeling; indeed, multiple pro-angiogenic factors, including vascular endothelial growth factor, regulate endothelial cell fate through an increase in intracellular Ca2+ concentration. Transient Receptor Potential (TRP) channel consist in a superfamily of non-selective cation channels that are widely expressed within vascular endothelial cells. In addition, TRP channels are present in the two main endothelial progenitor cell (EPC) populations, i.e., myeloid angiogenic cells (MACs) and endothelial colony forming cells (ECFCs). TRP channels are polymodal channels that can assemble in homo- and heteromeric complexes and may be sensitive to both pro-angiogenic cues and subtle changes in local microenvironment. These features render TRP channels the most versatile Ca2+ entry pathway in vascular endothelial cells and in EPCs. Herein, we describe how endothelial TRP channels stimulate vascular remodeling by promoting angiogenesis, arteriogenesis and vasculogenesis through the integration of multiple environmental, e.g., extracellular growth factors and chemokines, and intracellular, e.g., reactive oxygen species, a decrease in Mg2+ levels, or hypercholesterolemia, stimuli. In addition, we illustrate how endothelial TRP channels induce neovascularization in response to synthetic agonists and small molecule drugs. We focus the attention on TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, TRPV1, TRPV4, TRPM2, TRPM4, TRPM7, TRPA1, that were shown to be involved in angiogenesis, arteriogenesis and vasculogenesis. Finally, we discuss the role of endothelial TRP channels in aberrant tumor vascularization by focusing on TRPC1, TRPC3, TRPV2, TRPV4, TRPM8, and TRPA1. These observations suggest that endothelial TRP channels represent potential therapeutic targets in multiple disorders featured by abnormal vascularization, including cancer, ischemic disorders, retinal degeneration and neurodegeneration.
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Affiliation(s)
- Sharon Negri
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Pawan Faris
- Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Iraq
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Germano Guerra
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
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10
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Stretch-activated TRPV2 channels: Role in mediating cardiopathies. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:273-280. [PMID: 28546113 DOI: 10.1016/j.pbiomolbio.2017.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023]
Abstract
Transient receptor potential vanilloid type 2, TRPV2, is a calcium-permeable cation channel belonging to the TRPV channel family. Although this channel has been first characterized as a noxious heat sensor, its mechanosensor property recently gained importance in various physiological functions. TRPV2 has been described as a stretch-mediated channel and a regulator of calcium homeostasis in several cell types and has been shown to be involved in the stretch-dependent responses in cardiomyocytes. Hence, several studies in the last years support the idea that TRPV2 play a key role in the function and structure of the heart, being involved in the cardiac compensatory mechanisms in response to pathologic or exercise-induced stress. We present here an overview of the current literature and concepts of TRPV2 channels involvement (i) in the mechanical coupling mechanisms in heart and (ii) in the mechanisms that lead to cardiomyopathies. All these studies lead us to think that TRPV2 may also be an important cardiac drug target based on its major physiological roles in heart.
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11
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Sukumaran P, Schaar A, Sun Y, Singh BB. Functional role of TRP channels in modulating ER stress and Autophagy. Cell Calcium 2016; 60:123-32. [PMID: 26995055 DOI: 10.1016/j.ceca.2016.02.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 02/21/2016] [Accepted: 02/22/2016] [Indexed: 02/07/2023]
Abstract
Intracellular calcium (Ca(2+)) levels play a vital role in regulating cellular fate. The coordination and interrelation among the cellular organelles, mainly the intracellular Ca(2+) stores in endoplasmic reticulum (ER), are crucial in maintaining cytosolic Ca(2+) levels and in general cellular homeostasis. Moreover, maintaining Ca(2+) homeostasis is essential for regulating diverse and sometimes opposing processes such as cell survival and cell death in disease conditions such as, neurodegeneration, cancer and aging. Ca(2+) is able to regulate opposing functions by either regulating the cellular "self-eating" phenomenon of autophagy to promote cell survival or by regulating the programmed cell death process of apoptosis. Autophagy is also important for cell survival especially after induction of ER stress and association between ER stress and autophagy may have relevance to numerous diseases. Moreover, a multitude of evidence is emerging that the functional regulation of TRP channels, their unique localization, and their interaction with other Ca(2+)-sensing elements define these diverse regulatory pathways. It is this unique function which allows individual TRP channels to contribute differently in the regulation of cell fate and, in turn, determines the precise effect of modulating Ca(2+) signaling via the particular channel. Thus, in this review we have focused on the aspects of TRP channel localization and function (Ca(2+) signaling) that affects the ER stress and autophagic process.
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Affiliation(s)
- Pramod Sukumaran
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58201, United States
| | - Anne Schaar
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58201, United States
| | - Yuyang Sun
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58201, United States
| | - Brij B Singh
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58201, United States.
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12
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Permeation, regulation and control of expression of TRP channels by trace metal ions. Pflugers Arch 2014; 467:1143-64. [PMID: 25106481 PMCID: PMC4435931 DOI: 10.1007/s00424-014-1590-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/10/2014] [Accepted: 07/13/2014] [Indexed: 01/26/2023]
Abstract
Transient receptor potential (TRP) channels form a diverse family of cation channels comprising 28 members in mammals. Although some TRP proteins can only be found on intracellular membranes, most of the TRP protein isoforms reach the plasma membrane where they form ion channels and control a wide number of biological processes. There, their involvement in the transport of cations such as calcium and sodium has been well documented. However, a growing number of studies have started to expand our understanding of these proteins by showing that they also transport other biologically relevant metal ions like zinc, magnesium, manganese and cobalt. In addition to this newly recognized property, the activity and expression of TRP channels can be regulated by metal ions like magnesium, gadolinium, lanthanum or cisplatin. The aim of this review is to highlight the complex relationship between metal ions and TRP channels.
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Abstract
TRPV5 is one of the two channels in the TRPV family that exhibit high selectivity to Ca(2+) ions. TRPV5 mediates Ca(2+) influx into cells as the first step to transport Ca(2+) across epithelia. The specialized distribution in the distal tubule of the kidney positions TRPV5 as a key player in Ca(2+) reabsorption. The responsiveness in expression and/or activity of TRPV5 to hormones such as 1,25-dihydroxyvitamin D3, parathyroid hormone, estrogen, and testosterone makes TRPV5 suitable for its role in the fine-tuning of Ca(2+) reabsorption. This role is further optimized by the modulation of TRPV5 trafficking and activity via its binding partners; co-expressed proteins; tubular factors such as calbindin-D28k, calmodulin, klotho, uromodulin, and plasmin; extracellular and intracellular factors such as proton, Mg(2+), Ca(2+), and phosphatidylinositol-4,5-bisphosphate; and fluid flow. These regulations allow TRPV5 to adjust its overall activity in response to the body's demand for Ca(2+) and to prevent kidney stone formation. A point mutation in mouse Trpv5 gene leads to hypercalciuria similar to Trpv5 knockout mice, suggesting a possible role of TRPV5 in hypercalciuric disorders in humans. In addition, the single nucleotide polymorphisms in Trpv5 gene prevalently present in African descents may contribute to the efficient renal Ca(2+) reabsorption among African descendants. TRPV5 represents a potential therapeutic target for disorders with altered Ca(2+) homeostasis.
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Affiliation(s)
- Tao Na
- Cell Collection and Research Center, Institute for Biological Product Control, National Institutes for Food and Drug Control, Beijing, China
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Abstract
Hearing is a particularly sensitive form of mechanosensation that relies on dedicated ion channels transducing sound-induced vibrations that hardly exceed Brownian motion. Attempts to molecularly identify these auditory transduction channels have put the focus on TRPs in ears. In Drosophila, hearing has been shown to involve TRPA, TRPC, TRPN, and TRPV subfamily members, with candidate auditory transduction channels including NOMPC (=TRPN1) and the TRPVs Nan and Iav. In vertebrates, TRPs are unlikely to form auditory transduction channels, yet most TRPs are expressed in inner ear tissues, and mutations in TRPN1, TRPVA1, TRPML3, TRPV4, and TRPC3/TRPC6 have been implicated in inner ear function. Starting with a brief introduction of fly and vertebrate auditory anatomies and transduction mechanisms, this review summarizes our current understanding of the auditory roles of TRPs.
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Affiliation(s)
- Damiano Zanini
- Department of Cellular Neurobiology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
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Abstract
TRPML3 belongs to the MCOLN (TRPML) subfamily of transient receptor potential (TRP) channels comprising three genes in mammals. Since the discovery of the pain sensing, capsaicin- and heat-activated vanilloid receptor (TRPV1), TRP channels have been found to be involved in regulating almost all kinds of our sensory modalities. Thus, TRP channel members are sensitive to heat or cold; they are involved in pain or osmosensation, vision, hearing, or taste sensation. Loss or mutation of TRPML1 can cause retina degeneration and eventually blindness in mice and men (mucolipidosis type IV). Gain-of-function mutations in TRPML3 cause deafness and circling behavior in mice. A special feature of TRPML channels is their intracellular expression. They mostly reside in membranes of organelles of the endolysosomal system such as early and late endosomes, recycling endosomes, lysosomes, or lysosome-related organelles. Although the physiological roles of TRPML channels within the endolysosomal system are far from being fully understood, it is speculated that they are involved in the regulation of endolysosomal pH, fusion/fission processes, trafficking, autophagy, and/or (hormone) secretion and exocytosis.
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Abstract
Much excitement surrounded the proposal that a family of endo-lysosomal channels, the two-pore channels (TPCs) were the long sought after targets of the Ca(2+) -mobilising messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). However, the role of TPCs in NAADP signalling may be more complex than originally envisaged. First, NAADP may not bind directly to TPCs but via an accessory protein. Second, two papers recently challenged the notion that TPCs are NAADP-regulated Ca(2+) channels by suggesting that they are highly selective Na(+) channels regulated by the lipid phosphatidylinositol 3,5-bisphosphate and by ATP. This paper aims critically to evaluate the evidence for TPCs as NAADP targets and to discuss how the new findings fit in with what we know about endo-lysosomal Ca(2+) stores.
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Courjaret R, Hubrack S, Daalis A, Dib M, Machaca K. The
Xenopus
TRPV6 homolog encodes a Mg
2+
‐permeant channel that is inhibited by interaction with TRPC1. J Cell Physiol 2013; 228:2386-98. [DOI: 10.1002/jcp.24411] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/21/2013] [Indexed: 01/29/2023]
Affiliation(s)
- Raphael Courjaret
- Department of Physiology and BiophysicsWeill Cornell Medical College in QatarEducation City, Qatar FoundationDohaQatar
| | - Satanay Hubrack
- Department of Physiology and BiophysicsWeill Cornell Medical College in QatarEducation City, Qatar FoundationDohaQatar
| | - Arwa Daalis
- Department of Physiology and BiophysicsWeill Cornell Medical College in QatarEducation City, Qatar FoundationDohaQatar
| | - Maya Dib
- Department of Physiology and BiophysicsWeill Cornell Medical College in QatarEducation City, Qatar FoundationDohaQatar
| | - Khaled Machaca
- Department of Physiology and BiophysicsWeill Cornell Medical College in QatarEducation City, Qatar FoundationDohaQatar
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