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Overexpression CaT1 in Jurkat cell enhances I CRAC . A, families of currents in response to voltage steps showing steady-state currents after Ca 2 stores release in mock-transfected Jurkat cell (left) and CaT1-overexpressing cell (right). B, summary current-voltage (I-V) relationship between control and CaT1-expressed Jurkat cells. C, the time course in a mock-transfected Jurkat cell for development of inward Ca 2 current after establishing whole cell configuration at time 0 and responses to TG-induced store depletion and cycling between 0 and 2 mM external Ca 2 . (Inset shows voltage-ramp I-V curves from times indicated on time course.) D, time course for development of inward Ca 2 current in a Jurkat cell overexpressing CaT1. Upper trace is expanded to show maximal current. Lower trace of another cell is magnified to show TG response. E, time course of a JHMI cell overexpressing CaT1 in response to CCh and cycling between 0 and 2 mM external Ca 2 . F, histogram showing summary data of inward Ca 2 current densities after whole cell break in, after TG, with 0 mM external Ca 2 , and after reintroduction of 2 mM external Ca 2 . (* indicates p 0.05 by t test versus control Jurkat cells.)
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T-lymphocyte activation requires sustained Ca(2+) signaling dependent upon capacitative Ca(2+) entry (CCE). The protein(s) that forms the stores-operated Ca(2+) channel (SOCC) responsible for CCE has long been sought but has not been definitively identified. Members of the TRPV family (transient receptor potential superfamily-vanilloid receptor sub...
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... The TRPV receptors can be activated by many stimuli such as proton (H + ), heat, and natural substances such as 28, 77, and resiferatoxin [200][201][202]. In sensory neuronal fibers, the activation of TRPV1 by 77 triggers a rapid increase in Ca 2+ flux, causing neuronal depolarization and the characteristic burning sensation [203][204][205][206]. Compound 77 is also supposed to interact with other TRP receptors involved in cancer progression, such as TRPV6 [207] and TRPM8 [208]. Chow et al. (2007) [209] suggested that 77 induces apoptosis preferentially via TRPV6, with selectivity for tumor cells. ...
Piper, Capsicum, and Pimenta are the main genera of peppers consumed worldwide. The traditional use of peppers by either ancient civilizations or modern societies has raised interest in their biological applications, including cytotoxic and antiproliferative effects. Cellular responses upon treatment with isolated pepper-derived compounds involve mechanisms of cell death, especially through proapoptotic stimuli in tumorigenic cells. In this review, we highlight naturally occurring secondary metabolites of peppers with cytotoxic effects on cancer cell lines. Available mechanisms of cell death, as well as the development of analogues, are also discussed.
... CD3 + T cell Jurkat (Cell line) PBLs RT-PCR Immunofluorescence [57][58][59] TRPM2 ...
Allergy refers to an abnormal adaptive immune response to non-infectious environmental substances (allergen) that can induce various diseases such as asthma, atopic dermatitis, and allergic rhinitis. In this allergic inflammation, various immune cells, such as B cells, T cells, and mast cells, are involved and undergo complex interactions that cause a variety of pathophysiological conditions. In immune cells, calcium ions play a crucial role in controlling intracellular Ca2+ signaling pathways. Cations, such as Na+, indirectly modulate the calcium signal generation by regulating cell membrane potential. This intracellular Ca2+ signaling is mediated by various cation channels; among them, the transient receptor potential (TRP) family is present in almost all immune cell types, and each channel has a unique function in regulating Ca2+ signals. In this review, we focus on the role of TRP ion channels in allergic inflammatory responses in T cells and mast cells. In addition, the TRP ion channels, which are attracting attention in clinical practice in relation to allergic diseases, and current status of the development of therapeutic agents that target TRP channels are discussed.
... 131 Additionally, capsaicin has been reported to block TRPV6. 132 2-APB (2-aminoethoxydiphenyl borate), a store-operated calcium channel (SOC) inhibitor also effectively inhibited human TRPV6 but not TRPV5. 133 Searching for more specific inhibitors, Simonin et al. 134 described cis-22a through an in silico method of ligand-based virtual screening. ...
Many new insights into the molecular mechanisms of intestinal absorption of calcium, phosphate, and magnesium have been made over the past decade. These include the identification, cloning, and characterization of transmembrane proteins responsible for the absorption of all three of these nutrient molecules. The proteins identified for uptake of Ca²⁺ and Mg²⁺ across the apical membrane of enterocytes are members of the transient receptor potential (TRP) family of cation channels (TRPV6 for Ca²⁺ and TRPM6/7 heterotetramers for Mg²⁺), while intestinal Pi absorption across the apical membrane is now known to be mediated by a member of the sodium-phosphate cotransporter gene family (NaPi-IIb; SLC34A2). Additionally, in some cases, molecules responsible for movement of these molecules across the cellular cytoplasm (e.g., calbindins for Ca²⁺) and exit across the basolateral membranes (e.g., plasma membrane calcium ATPase [PMCA1b] and the Na⁺/Mg²⁺ exchanger) of intestinal epithelial cells have also been identified and extensively studied. With the discovery of these channels and transporters, we now have a much clearer picture of the molecular mechanisms involved in the transport of these crucial nutrient molecules. However, for all three of these molecules, transport proteins involved in transcellular uptake seem to be important only when intake levels are low, as at higher dietary intake levels, absorption occurs passively via still relatively obscure, paracellular transport pathways. Furthermore, additional information has shown that these transport processes are regulated by a number of physiological mediators, and that these effects are mediated by direct influences on the expression or activity of the identified transporters.
... HEK293 cells were maintained in minimal essential medium with 10% fetal bovine serum (HyClone) and 1% penicillin/streptomycin (Mediatech) in a humidified, 5% CO 2 incubator at 37 °C. Cells were transfected using the Effectene transfection reagent (Qiagen) with the following constructs: either the wild-type or mutant TRPV6 in pCMV-tag3A vector 55 , ciVSP in an EGFP-IRES vector, and pEGFPN1 as a transfection marker in experiments without ciVSP. The rat TRPV5 clone (CaT2) 56 was sublconed into the pCDNA3.1(− ) vector using standard molecular biology tools. ...
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is an important cofactor for ion channels. Affinity for this lipid is a major determinant of channel inhibition by depletion of PI(4,5)P2 upon phospholipase C (PLC) activation. Little is known about what determines PI(4,5)P2 affinity in mammalian ion channels. Here we report that two members of the Transient Receptor Potential Vanilloid (TRPV) ion channel family, TRPV5 and TRPV6 lack a positively charged residue in the TM4-TM5 loop that was shown to interact with PI(4,5)P2 in TRPV1, which shows high affinity for this lipid. When this positively charged residue was introduced to either TRPV6 or TRPV5, they displayed markedly higher affinities for PI(4,5)P2, and were largely resistant to inhibition by PI(4,5)P2 depletion. Furthermore, Ca(2+)-induced inactivation of TRPV6 was essentially eliminated in the G488R mutant, showing the importance of PLC-mediated PI(4,5)P2 depletion in this process. Computational modeling shows that the introduced positive charge interacts with PI(4,5)P2 in TRPV6.
... The functional expression of the Ca 2+ -selective TRPV5 and TRPV6 channels was reported in mouse and human primary T cells and in Jurkat cells [15,50,51]. However, Trpv6 −/ − mice have no reported immunological phenotype [52] and TCR-induced Ca 2+ influx in CD4 + T cells from Trpv6 −/− mice is normal [53]. ...
... However, Trpv6 −/ − mice have no reported immunological phenotype [52] and TCR-induced Ca 2+ influx in CD4 + T cells from Trpv6 −/− mice is normal [53]. The TRPV6 channel, which is highly permeable to Ca 2+ , was shown to be triggered by store depletion [51] and, as certain TRPC subfamily members, was considered as a potential molecular entity of the CRAC channel. When a dominant-negative pore-region mutant of TRPV6 was expressed in Jurkat T cells, the CRAC current was found to be reduced [51]. ...
... The TRPV6 channel, which is highly permeable to Ca 2+ , was shown to be triggered by store depletion [51] and, as certain TRPC subfamily members, was considered as a potential molecular entity of the CRAC channel. When a dominant-negative pore-region mutant of TRPV6 was expressed in Jurkat T cells, the CRAC current was found to be reduced [51]. However, the role of TRPV6 as a CRAC channel could not be established [54,55] as BTP2 (a pyrazole derivative and CRAC channel inhibitor) did not affect the activity of the TRPV6 channel [56]. ...
The transient receptor potential (TRP) family of ion channels is widely expressed in many cell types and plays various physiological roles. Growing evidence suggests that certain TRP channels are functionally expressed in the immune system. Indeed, an increasing number of reports have demonstrated the functional expression of several TRP channels in innate and adaptive immune cells and have highlighted their critical role in the activation and function of these cells. However, very few reviews have been entirely dedicated to this subject. Here, we will summarize the recent findings with regards to TRP channel expression in T cells and discuss their emerging role as regulators of T cell activation and functions. Moreover, these studies suggest that beyond their pharmaceutical interest in pain management, certain TRP channels may represent potential novel therapeutic targets for various immune-related diseases.
... From 1992-2005, numerous candidate genes were proposed to encode the CRAC channel, and many mechanisms were hypothesized to explain its coupling to ER Ca 2ϩ content (283). Based on early speculation that Drosophila TRP channels were store operated (419), the most prominent CRAC channel candidates were mammalian TRP homologs (including TRPC1, TRPC3, and TRPV6) (67,251,295,435). However, when expressed heterologously their Ca 2ϩ selectivity and conductance failed to match those of I CRAC (399), and it was not clear in many cases whether the channels were truly store operated (74). ...
Store-operated cofor 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 Ca2+ 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 Ca2+ 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 Ca2+ 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 Ca2+ 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.
... Interestingly, TRP channels were evaluated as potential candidates for the CRAC channel prior to the discovery of ORAI1 and STIM1. The TRPV6 channel, which is highly permeable to Ca 2+ , was shown to be induced by store depletion (53). When a dominant-negative pore-region mutant of TRPV6 was expressed in Jurkat T cells, it was found that the CRAC current was reduced (53). ...
... The TRPV6 channel, which is highly permeable to Ca 2+ , was shown to be induced by store depletion (53). When a dominant-negative pore-region mutant of TRPV6 was expressed in Jurkat T cells, it was found that the CRAC current was reduced (53). However, the role of TRPV6 as a CRAC channel could not be established (54,55), since BTP2, a CRAC channel inhibitor, did not show an effect on the activity of the TRPV6 channel (56)(57)(58). ...
Elevation of intracellular calcium ion (Ca²⁺) levels is a vital event that regulates T lymphocyte homeostasis, activation, proliferation, differentiation, and apoptosis. The mechanisms that regulate intracellular Ca²⁺ signaling in lymphocytes involve tightly controlled concinnity of multiple ion channels, membrane receptors, and signaling molecules. T cell receptor (TCR) engagement results in depletion of endoplasmic reticulum (ER) Ca²⁺ stores and subsequent sustained influx of extracellular Ca²⁺ through Ca²⁺ release-activated Ca²⁺ (CRAC) channels in the plasma membrane. This process termed store-operated Ca²⁺ entry (SOCE) involves the ER Ca²⁺ sensing molecule, STIM1, and a pore-forming plasma membrane protein, ORAI1. However, several other important Ca²⁺ channels that are instrumental in T cell function also exist. In this review, we discuss the role of additional Ca²⁺ channel families expressed on the plasma membrane of T cells that likely contribute to Ca²⁺ influx following TCR engagement, which include the TRP channels, the NMDA receptors, the P2X receptors, and the IP3 receptors, with a focus on the voltage-dependent Ca²⁺ (CaV) channels.
... Previously it was also demonstrated that prolonged activation of TRPV1 by capsaicin (in lM concentrations) in CD5 + rat thymocytes leads to apoptotic and necrotic cell death [34]. In contrast to the thermosensitive TRPV members, TRPV6 (CaT1) has been detected by RT-PCR in Jurkat cells where it is involved in generation of store operated Ca 2+ entry, necessary for activation of Jurkat cells [52,53]. TRPV5 and TRPV6 at mRNA as well as at protein levels have also been detected in Jurkat and human T lymphocytes [54]. ...
The importance of Ca(2+) -signaling and temperature in the context of T cell activation is well known. However, the molecular identities of key players involved in such critical regulations are still unknown. In this work we explored the endogenous expression of Transient Receptor Potential Vanilloid channels, a group of thermosensitive and non-selective cation channels, in T cells. Using flow cytometry and confocal microscopy, we demonstrate that members belonging to TRPV subfamily are expressed endogenously in the human T cell line Jurkat, in primary human T cells and in primary murine splenic T cells. We also demonstrate that TRPV1- and TRPV4-specific agonists namely RTX and 4αPDD can cause Ca(2+) -influx in T cells. Moreover, our results show that expression of these channels could be up-regulated in T cells during ConA-driven mitogenic activation of T cells. By specific blocking of TRPV1 and TRPV4 channels, we found that these TRPV inhibitors may regulate mitogenic and TCR-mediated T cell activation and effector cytokine(s) production by suppressing TNF, IL-2 and IFNγ release. These results may have broad implication in the context of cell-mediated immunity, especially T cell responses and their regulations, neuro-immune interactions and molecular understanding of channelopathies. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
... Indeed, inhibition of TRPV currents by RR arrested the progression of the cell cycle in activated PBLs or Jurkat in G0/G1 and S or G2/M phases, respectively [259]. TRPV6 in Jurkat may physically interact with or even contribute to the CRAC/SOCE [260]. ...
T leukemogenesis is a multistep process, where the genetic errors during T cell maturation cause the healthy progenitor to convert into the leukemic precursor that lost its ability to differentiate but possesses high potential for proliferation, self-renewal, and migration. A new misdirecting " leukemogenic " signaling network appears, composed by three types of participants which are encoded by (1) genes implicated in determined stages of T cell development but deregulated by translocations or mutations, (2) genes which normally do not participate in T cell development but are upregulated, and (3) nondifferentially expressed genes which become highly interconnected with genes expressed differentially. It appears that each of three groups may contain genes coding ion channels. In T cells, ion channels are implicated in regulation of cell cycle progression, differentiation, activation, migration, and cell death. In the present review we are going to reveal a relationship between different genetic defects, which drive the T cell neoplasias, with calcium signaling and ion channels. We suggest that changes in regulation of various ion channels in different types of the T leukemias may provide the intracellular ion microenvironment favorable to maintain self-renewal capacity, arrest differentiation, induce proliferation, and enhance motility.
... Transcripts for TRPV2, TRPV3 and TRPV4 are found in thymocytes, splenocytes, lymphocytes or purified B-cells and T-cells of C57BL/6 mice (Inada et al., 2006) and TRPV1 and TRPV2 are detected in human PBMCs (Saunders et al., 2007(Saunders et al., , 2009). Strong and prolonged activation of TRPV1 by capsaicin induces apoptosis in CD5 + thymocytes (Amantini et al., 2004) and TRPV6 in Jurkat cells are involved in store operated Ca 2+ -entry, an essential process involved in T-cell activation (Cui et al., 2002;Yue et al., 2001). Both transcript and proteins of TRPV5 and TRPV6 have been detected in Jurkat and human T-lymphocytes (Vasil'eva et al., 2008). ...
While effects of different steroids on the gene expression and regulation are well established, it is proven that steroids can also exert rapid non-genomic actions in several tissues and cells. In most cases, these non-genomic rapid effects of steroids are actually due to intracellular mobilization of Ca2+- and other ions suggesting that Ca2+ channels are involved in such effects. Transient Receptor Potential (TRP) ion channels or TRPs are the largest group of non-selective and polymodal ion channels which cause Ca2+-influx in response to different physical and chemical stimuli. While non-genomic actions of different steroids on different ion channels have been established to some extent, involvement of TRPs in such functions is largely unexplored. In this review, we critically analyze the literature and summarize how different steroids as well as their metabolic precursors and derivatives can exert non-genomic effects by acting on different TRPs qualitatively and/or quantitatively. Such effects have physiological repercussion on systems such as in sperm cells, immune cells, bone cells, neuronal cells and many others. Different TRPs are also endogenously expressed in diverse steroid-producing tissues and thus may have importance in steroid synthesis as well, a process which is tightly controlled by the intracellular Ca2+ concentrations. Tissue and cell-specific expression of TRP channels are also regulated by different steroids. Understanding of the crosstalk between TRP channels and different steroids may have strong significance in physiological, endocrinological and pharmacological context and in future these compounds can also be used as potential biomedicine.
