New Screening System for Selective Blockers of Voltage-Gated K+ Channels Using Recombinant Cell Lines Dying Upon Single Action Potential

Fujisawa, Masato; Hayashi, Keisuke; Ohya, Susumu; Yamamura, Hisao; Imaizumi, Yuji

doi:10.1254/jphs.13063fp

Cited by 9 publications

(6 citation statements)

References 33 publications

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“…Recently, several studies suggested the effects of citalopram on ion channels. For example, citalopram inhibited the Kv1.3 and Kv1.5 subtypes in cell lines co-expressing Nav1.5, Kir2.1, Kv1.3, and Kv1.5 [21]. In addition, citalopram inhibited the Nav1.7 and Nav1.8 channels that are expressed in human embryonic kidney (HEK) 293 cells [22].…”

Section: Discussionmentioning

confidence: 99%

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells

Kim

et al. 2017

Korean J Physiol Pharmacol

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We investigated the inhibitory effect of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on voltage-dependent K+ (Kv) channels in freshly separated from rabbit coronary arterial smooth muscle cells. The application of escitalopram rapidly inhibited vascular Kv channels. Kv currents were progressively inhibited by an increase in the concentrations of escitalopram, suggesting that escitalopram inhibited vascular Kv currents in a concentration-dependent manner. The IC50 value and Hill coefficient for escitalopram-induced inhibition of Kv channels were 9.54±1.33 µM and 0.75±0.10, respectively. Addition of escitalopram did not alter the steady-state activation and inactivation curves, suggesting that the voltage sensors of the channels were not affected. Pretreatment with inhibitors of Kv1.5 and/or Kv2.1 did not affect the inhibitory action of escitalopram on vascular Kv channels. From these results, we concluded that escitalopram decreased the vascular Kv current in a concentration-dependent manner, independent of serotonin reuptake inhibition.

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Section: Discussionmentioning

confidence: 99%

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells

Kim

et al. 2017

Korean J Physiol Pharmacol

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“…Acacetin has been found to block multiple potassium channels, including cloned Kv1.3 channels expressed in recombinant cell lines [4,5]. The Kv1.3 channel, a member of the Shaker family of potassium channels, is mainly expressed in immune cells such as T cells, macrophages and dendritic cells [6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Acacetin Blocks Kv1.3 Channels and Inhibits Human T Cell Activation

Zhao

et al. 2014

Cell Physiol Biochem

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Backgrounds/Aims: Acacetin, a natural flavonoid compound, has been proven to exert anti-inflammatory and immunomodulatory effects. Kv1.3 channels, highly expressed in human T cells, are attractive therapeutic targets to treat inflammatory and immunological disorders. The present study was designed to characterize the inhibition of Kv1.3 channels by Acacetin in human T cells and examine its role in T cell activation. Methods: Whole-cell patch-clamp was applied to record the Kv1.3 and K_Ca currents in human T cells; Western blot was used to detect Kv1.3 expression as well as NFAT1 and NF-κB activity; Fluo-4, CCK-8 and an ELISA kit were used to measure Ca²⁺ influx, proliferation, and IL-2 secretion, respectively. Results: Acacetin decreased the Kv1.3 current, accelerated the decay rate and negatively shifted the steady-state inactivation curves in a concentration-dependent manner. The IC₅₀ values at +40 mV for peak and the current at end of pulse were 21.09 ± 2.75 and 3.63 ± 0.25 µmol/L, respectively. Treatment with Acacetin for 24 h significantly inhibited Kv1.3 protein expression. Additionally, paralleling Kv1.3 inhibition, Acacetin also inhibited Ca²⁺ influx, the Ca²⁺-activated transcription factors NFAT1, NF-κB p65/p50 activity, and proliferation as well as IL-2 production. Small interfering RNA against Kv1.3 reduced the inhibitory effect of Acacetin on IL-2 secretion. Conclusions: Acacetin blocks the Kv1.3 channel and inhibits human T cell activation. This action most likely contributes to its immunomodulatory and anti-inflammatory actions.

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“…The pipette solution for whole-cell recordings contained (in mM) KCl 140, MgCl 2 4, HEPES 10, Na 2 ATP 2, and EGTA 0.05. The pH of the pipette solution was adjusted to 7.2 with KOH (Fujii et al, 2013). …”

Section: Methodsmentioning

confidence: 99%

Electrophysiological Characteristics of the LQT2 Syndrome Mutation KCNH2-G572S and Regulation by Accessory Protein KCNE2

Liu

Tian

et al. 2016

Front. Physiol.

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Mutations in hERG cause long QT syndrome type 2 which is characterized by a prolonged QT interval on electrocardiogram and predisposition to life-threatening ventricular tachyarrhythmia, syncope, and sudden death. hERG-G572S induces trafficking defects of hERG channel protein from Golgi to the plasma membrane and results in a dominant negative suppression of hERG current density. As an accessory β subunit, KCNE2 promotes hERG migration from Golgi to cellular membrane. In this study, we investigated the rescue effect of KCNE2 in a G572S mutation of hERG. Transfection was performed into HEK293 cells. Patch clamp technique, western blotting analyses and confocal microscopic examination were used. Results showed that KCNE2 had a significantly enhanced effect on G572S mutation current. The increase of current was largest at KCNH2:KCNE2 of 1:3. Confocal images showed co-expressing G572S and KCNE2 could cause a substantial up-regulated membrane protein (155 kDa) expression. Expression of membrane protein accumulated markedly with increasing ratio of KCNH2:KCNE2. G572S defective mutant could be restored by both KCNE2 and lower temperature (27°C), which suggested that the lower temperature could be the favorable circumstances for the rescue function of KCNE2. In this study, we successfully set up “the action potential” on the HEK 293 cells by genetically engineered to express Kir2.1, Nav1.5, and Kv11.1, wherein on reaching over an excitation threshold by current injection. The results suggested that KCNE2 could shorten action potential duration which was prolonged by G572S. These findings described electrophysiological characteristics of the LQT2 syndrome mutation KCNH2-G572S and regulation by accessory protein KCNE2, and provided a clue about LQT2 and relative rescue mechanism.

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New Screening System for Selective Blockers of Voltage-Gated K+ Channels Using Recombinant Cell Lines Dying Upon Single Action Potential

Cited by 9 publications

References 33 publications

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells

Acacetin Blocks Kv1.3 Channels and Inhibits Human T Cell Activation

Electrophysiological Characteristics of the LQT2 Syndrome Mutation KCNH2-G572S and Regulation by Accessory Protein KCNE2

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New Screening System for Selective Blockers of Voltage-Gated K+ Channels Using Recombinant Cell Lines Dying Upon Single Action Potential

Cited by 9 publications

References 33 publications

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K+channels in coronary arterial smooth muscle cells

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K+channels in coronary arterial smooth muscle cells

Acacetin Blocks Kv1.3 Channels and Inhibits Human T Cell Activation

Electrophysiological Characteristics of the LQT2 Syndrome Mutation KCNH2-G572S and Regulation by Accessory Protein KCNE2

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Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁺channels in coronary arterial smooth muscle cells