Chlorpromazine inhibits store-operated calcium entry and subsequent noradrenaline secretion in PC12 cells.
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ABSTRACT:
SUBMITTER: Choi SY
PROVIDER: S-EPMC1572582 | biostudies-other | 2001 Jan
REPOSITORIES: biostudies-other
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Project description:In this study, we investigated the role of peroxisome proliferator-activated receptor ? (PPAR?) on store-operated calcium entry (SOCE) and expression of the main store-operated calcium channel (SOCCs) components, canonical transient receptor potential (TRPC) in chronic hypoxia (CH)-induced pulmonary hypertension (CHPH) rat models. Small interfering RNA (siRNA) knockdown and adenoviral overexpression strategies were constructed for loss-of-function and gain-of-function experiments. PPAR? agonist rosiglitazone attenuates the pathogenesis of CHPH and suppresses Hif-1?, TRPC1, TRPC6 expression in the distal pulmonary arteries (PA), and SOCE in freshly isolated rat distal pulmonary arterial smooth muscle cells (PASMCs). By comprehensive use of knockdown and overexpression studies, and bioinformatical analysis of the TRPC gene promoter and luciferase reporter assay, we demonstrated that PPAR? exerts roles of anti-proliferation, anti-migration, and pro-apoptosis in PASMCs, likely by inhibiting the elevated SOCE and TRPC expression. These effects were inhibited under the conditions of hypoxia or Hif-1? accumulation. We also found that under hypoxia, accumulated Hif-1? protein acts as upstream of suppressed PPAR? level; however, targeted PPAR? rescue acts as negative feedback on suppressing Hif-1? level and Hif-1? mediated signaling pathway. PPAR? inhibits CHPH by targeting SOCE and TRPC via inhibiting Hif-1? expression and signaling transduction.Rosiglitazone protects PH by normalizing RVSP but not right ventricle hypotrophy. PPAR? inhibits PASMCs proliferation via targeting SOCE and TRPC by suppressing Hif-1?. PPAR? and Hif-1? share mutual inhibitory regulation in PASMCs. PPAR? restoration might be a beneficial strategy for PH treatment.
| S-EPMC4334731 | biostudies-literature
Project description:Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca(2+) signals that define the "Ca(2+) excitability" of glia. In mammalian glial cells the major source of Ca(2+) for this excitability is the lumen of the endoplasmic reticulum (ER), which is ultimately (re)filled from the extracellular space. This occurs via store-operated Ca(2+) entry (SOCE) which is supported by a specific signaling system connecting the ER with plasmalemmal Ca(2+) entry. Here, emptying of the ER Ca(2+) store is necessary and sufficient for the activation of SOCE, and without Ca(2+) influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca(2+) sensors, such as stromal interaction molecule, and possibly ER Ca(2+) pumps (of the SERCA type). There are at least two sets of plasmalemmal channels mediating SOCE, the Ca(2+)-release activated channels, Orai, and transient receptor potential (TRP) channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca(2+) signal observed following stimulation of metabotropic receptors on glial cells.
| S-EPMC5561850 | biostudies-other
Project description:Orai1 interacts with transient receptor potential protein of the canonical subfamily (TRPC4) and contributes to calcium selectivity of the endothelial cell store-operated calcium entry current (ISOC). Orai1 silencing increases sodium permeability and decreases membrane-associated calcium, although it is not known whether Orai1 is an important determinant of cytosolic sodium transitions. We test the hypothesis that, upon activation of store-operated calcium entry channels, Orai1 is a critical determinant of cytosolic sodium transitions. Activation of store-operated calcium entry channels transiently increased cytosolic calcium and sodium, characteristic of release from an intracellular store. The sodium response occurred more abruptly and returned to baseline more rapidly than did the transient calcium rise. Extracellular choline substitution for sodium did not inhibit the response, although 2-aminoethoxydiphenyl borate and YM-58483 reduced it by ?50%. After this transient response, cytosolic sodium continued to increase due to influx through activated store-operated calcium entry channels. The magnitude of this sustained increase in cytosolic sodium was greater when experiments were conducted in low extracellular calcium and when Orai1 expression was silenced; these two interventions were not additive, suggesting a common mechanism. 2-Aminoethoxydiphenyl borate and YM-58483 inhibited the sustained increase in cytosolic sodium, only in the presence of Orai1. These studies demonstrate that sodium permeates activated store-operated calcium entry channels, resulting in an increase in cytosolic sodium; the magnitude of this response is determined by Orai1.
| S-EPMC4329424 | biostudies-literature
Project description:Cellular homeostasis relies upon precise regulation of Ca(2+) concentration. Stromal interaction molecule (STIM) proteins regulate store-operated calcium entry (SOCE) by sensing Ca(2+) concentration in the ER and forming oligomers to trigger Ca(2+) entry through plasma membrane-localized Orai1 channels. Here we characterize a STIM2 splice variant, STIM2.1, which retains an additional exon within the region encoding the channel-activating domain. Expression of STIM2.1 is ubiquitous but its abundance relative to the more common STIM2.2 variant is dependent upon cell type and highest in naive T cells. STIM2.1 knockdown increases SOCE in naive CD4(+) T cells, whereas knockdown of STIM2.2 decreases SOCE. Conversely, overexpression of STIM2.1, but not STIM2.2, decreases SOCE, indicating its inhibitory role. STIM2.1 interaction with Orai1 is impaired and prevents Orai1 activation, but STIM2.1 shows increased affinity towards calmodulin. Our results imply STIM2.1 as an additional player tuning Orai1 activation in vivo.
| S-EPMC4411291 | biostudies-literature
Project description:Calcium entry from the extracellular space into cells is an important signaling mechanism in both physiological and pathophysiological functions. In non-excitable cells, store-operated calcium (SOC) entry represents a principal mode of calcium entry. Activation of SOC entry in pulmonary artery endothelial cells leads to the formation of inter-endothelial cell gaps and subsequent endothelial barrier disruption. Regulation of endothelial SOC entry is poorly understood. In this work, we identify two large molecular weight immunophilins, FKBP51 and FKBP52, as novel regulators of SOC entry in endothelial cells. Using cell fractionation studies and immunocytochemistry we determined that a fraction of these largely cytosolic proteins localize to the plasma membrane where SOC entry channels are found. That FKBP51 and FKBP52 associate with SOC entry channel protein complexes was supported by co-precipitation of the immunophilins with TRPC4, a subunit of the calcium-selective, SOC entry channel ISOC. Dexamethasone-induced upregulation of FKBP51 expression in pulmonary artery endothelial cells reduced global SOC entry as well as ISOC. Similar results were observed when FKBP51 was over-expressed in an inducible HEK293 cell line. On the other hand, when FKBP52 was over-expressed SOC entry was enhanced. When expression of FKBP52 was inhibited, SOC entry was decreased. Collectively, our observations support regulatory roles for these large molecular weight immunophilins in which FKBP51 inhibits, whereas FKBP52 enhances, SOC entry in endothelial cells.
| S-EPMC3593819 | biostudies-literature
Project description:Store-operated calcium entry (SOCE) is the mechanism by which extracellular signals elicit prolonged intracellular calcium elevation to drive changes in fundamental cellular processes. Here, we investigated the role of SOCE in the regulation of renal water reabsorption, using the inbred rat strain SHR-A3 as an animal model with disrupted SOCE. We found that SHR-A3, but not SHR-B2, have a novel truncating mutation in the gene encoding stromal interaction molecule 1 (STIM1), the endoplasmic reticulum calcium (Ca(2+)) sensor that triggers SOCE. Balance studies revealed increased urine volume, hypertonic plasma, polydipsia, and impaired urinary concentrating ability accompanied by elevated circulating arginine vasopressin (AVP) levels in SHR-A3 compared with SHR-B2. Isolated, split-open collecting ducts (CD) from SHR-A3 displayed decreased basal intracellular Ca(2+) levels and a major defect in SOCE. Consequently, AVP failed to induce the sustained intracellular Ca(2+) mobilization that requires SOCE in CD cells from SHR-A3. This effect decreased the abundance of aquaporin 2 and enhanced its intracellular retention, suggesting impaired sensitivity of the CD to AVP in SHR-A3. Stim1 knockdown in cultured mpkCCDc14 cells reduced SOCE and basal intracellular Ca(2+) levels and prevented AVP-induced translocation of aquaporin 2, further suggesting the effects in SHR-A3 result from the expression of truncated STIM1. Overall, these results identify a novel mechanism of nephrogenic diabetes insipidus and uncover a role of SOCE in renal water handling.
| S-EPMC4926963 | biostudies-literature
Project description:In non-excitable cells, activation of G-protein-coupled phospholipase C (PLC)-linked receptors causes the release of Ca(2+) from intracellular stores, which is followed by transmembrane Ca(2+) entry. This Ca(2+) entry underlies a small and sustained phase of the cellular [Ca(2+)](i) increases and is important for several cellular functions including gene expression, secretion and cell proliferation. This form of transmembrane Ca(2+) entry is supported by agonist-activated Ca(2+)-permeable ion channels that are activated by store depletion and is referred to as store-operated Ca(2+) entry (SOCE) and represents a major pathway for agonist-induced Ca(2+) entry. In excitable cells such as smooth muscle cells, Ca(2+) entry mechanisms responsible for sustained cellular activation are normally considered to be mediated via either voltage-operated or receptor-operated Ca(2+) channels. Although SOCE occurs following agonist activation of smooth muscle, this was thought to be more important in replenishing Ca(2+) stores rather than acting as a source of activator Ca(2+) for the contractile process. This review summarizes our current knowledge of SOCE as a regulator of vascular smooth muscle tone and discusses its possible role in the cardiovascular function and disease. We propose a possible hypothesis for its activation and suggest that SOCE may represent a novel target for pharmacological therapeutic intervention.
| S-EPMC2267267 | biostudies-other
Project description:Cardiac hypertrophy is a major risk factor for heart failure, which are among the leading causes of human death. Gastrodin is a small molecule that has been used clinically to treat neurological and vascular diseases for many years without safety issues. In the present study, we examined protective effect of gastrodin against cardiac hypertrophy and explored the underlying mechanism. Phenylephrine and angiotensin II were used to induce cardiac hypertrophy in a mouse model and a cultured cardiomyocyte model. Gastrodin was found to alleviate the cardiac hypertrophy in both models. Mechanistically, gastrodin attenuated the store-operated Ca2+ entry (SOCE) by reducing the expression of STIM1 and Orai1, two key proteins in SOCE, in animal models as well as in cultured cardiomyocyte model. Furthermore, suppressing SOCE by RO2959, Orai1-siRNAs or STIM1-siRNAs markedly attenuated the phenylephrine-induced hypertrophy in cultured cardiomyocyte model. Together, these results showed that gastrodin inhibited cardiac hypertrophy and it also reduced the SOCE via its action on the expression of STIM1 and Orai1. Furthermore, suppression of SOCE could reduce the phenylephrine-induced cardiomyocyte hypertrophy, suggesting that SOCE-STIM1-Orai1 is located upstream of hypertrophy.
| S-EPMC5404510 | biostudies-literature
Project description:Calcium signals are initiated in immune cells by the process of store-operated calcium entry (SOCE), where receptor activation triggers transient calcium release from the endoplasmic reticulum, followed by opening of plasma membrane calcium-release activated calcium (CRAC) channels. ORAI1, ORAI2 and ORAI3 are known to comprise the CRAC channel, however the contributions of individual isoforms to neutrophil function is not well understood. Here we show that loss of ORAI1 partially decreases calcium influx while loss of both ORAI1 and ORAI2 completely abolishes store-operated calcium entry. In other immune cell types, loss of ORAI2 enhances SOCE. In contrast, we find that ORAI2-deficient neutrophils display decreased calcium influx, which is correlated with measurable differences in regulation of neutrophil membrane potential via KCa3.1. Decreased SOCE in ORAI1-, ORAI2- and ORAI1/2-deficient neutrophils impairs multiple neutrophil functions including phagocytosis, degranulation, leukotriene and ROS production, rendering ORAI1/2-deficient mice highly susceptible to staphylococcal infection. This study demonstrates that ORAI1 and ORAI2 are the primary components of the neutrophil CRAC channel and identifies novel subpopulations of neutrophils where cell membrane potential functions as a rheostat to modulate the SOCE response. These findings have implications for new mechanisms that modulate neutrophil function during infection, acute and chronic inflammatory conditions, and cancer.
2020-09-01 | GSE157200 | GEO
Project description:It is well-established that astrocytes respond to norepinephrine with cytosolic calcium rises in various brain areas, such as hippocampus or neocortex. However, less is known about the effect of norepinephrine on olfactory bulb astrocytes. In the present study, we used confocal calcium imaging and immunohistochemistry in mouse brain slices of the olfactory bulb, a brain region with a dense innervation of noradrenergic fibers, to investigate the calcium signaling evoked by norepinephrine in astrocytes. Our results show that application of norepinephrine leads to a cytosolic calcium rise in astrocytes which is independent of neuronal activity and mainly mediated by PLC/IP3-dependent internal calcium release. In addition, store-operated calcium entry (SOCE) contributes to the late phase of the response. Antagonists of both α1- and α2-adrenergic receptors, but not β-receptors, largely reduce the adrenergic calcium response, indicating that both α-receptor subtypes mediate norepinephrine-induced calcium transients in olfactory bulb astrocytes, whereas β-receptors do not contribute to the calcium transients.
| S-EPMC8021869 | biostudies-literature