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Stroedecke K, Meinel S, Markwardt F, Kloeckner U, Straetz N, Quarch K, Schreier B, Kopf M, Gekle M, Grossmann C. The mineralocorticoid receptor leads to increased expression of EGFR and T-type calcium channels that support HL-1 cell hypertrophy. Sci Rep 2021; 11:13229. [PMID: 34168192 PMCID: PMC8225817 DOI: 10.1038/s41598-021-92284-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/05/2021] [Indexed: 11/12/2022] Open
Abstract
The EGF receptor (EGFR) has been extensively studied in tumor biology and recently a role in cardiovascular pathophysiology was suggested. The mineralocorticoid receptor (MR) is an important effector of the renin-angiotensin-aldosterone-system and elicits pathophysiological effects in the cardiovascular system; however, the underlying molecular mechanisms are unclear. Our aim was to investigate the importance of EGFR for MR-mediated cardiovascular pathophysiology because MR is known to induce EGFR expression. We identified a SNP within the EGFR promoter that modulates MR-induced EGFR expression. In RNA-sequencing and qPCR experiments in heart tissue of EGFR KO and WT mice, changes in EGFR abundance led to differential expression of cardiac ion channels, especially of the T-type calcium channel CACNA1H. Accordingly, CACNA1H expression was increased in WT mice after in vivo MR activation by aldosterone but not in respective EGFR KO mice. Aldosterone- and EGF-responsiveness of CACNA1H expression was confirmed in HL-1 cells by Western blot and by measuring peak current density of T-type calcium channels. Aldosterone-induced CACNA1H protein expression could be abrogated by the EGFR inhibitor AG1478. Furthermore, inhibition of T-type calcium channels with mibefradil or ML218 reduced diameter, volume and BNP levels in HL-1 cells. In conclusion the MR regulates EGFR and CACNA1H expression, which has an effect on HL-1 cell diameter, and the extent of this regulation seems to depend on the SNP-216 (G/T) genotype. This suggests that the EGFR may be an intermediate for MR-mediated cardiovascular changes and that SNP analysis can help identify subgroups of patients that will benefit most from MR antagonists.
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Affiliation(s)
- Katharina Stroedecke
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Sandra Meinel
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Fritz Markwardt
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Udo Kloeckner
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Nicole Straetz
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Katja Quarch
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Barbara Schreier
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Michael Kopf
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Michael Gekle
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Claudia Grossmann
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany.
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Fusi F, Trezza A, Tramaglino M, Sgaragli G, Saponara S, Spiga O. The beneficial health effects of flavonoids on the cardiovascular system: Focus on K+ channels. Pharmacol Res 2020; 152:104625. [DOI: 10.1016/j.phrs.2019.104625] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/14/2019] [Accepted: 12/31/2019] [Indexed: 01/17/2023]
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Effects of equol on multiple K+ channels stably expressed in HEK 293 cells. PLoS One 2017; 12:e0183708. [PMID: 28832658 PMCID: PMC5568406 DOI: 10.1371/journal.pone.0183708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
The present study investigated the effects of equol on cardiovascular K+ channel currents. The cardiovascular K+ channel currents were determined in HEK 293 cells stably expressing cloned differential cardiovascular K+ channels with conventional whole-cell patch voltage-clamp technique. We found that equol inhibited hKv1.5 (IC50: 15.3 μM), hKv4.3 (IC50: 29.2 μM and 11.9 μM for hKv4.3 peak current and charge area, respectively), IKs (IC50: 24.7 μM) and IhERG (IC50: 31.6 and 56.5 μM for IhERG.tail and IhERG.step, respectively), but not hKir2.1 current, in a concentration-dependent manner. Interestingly, equol increased BKCa current with an EC50 of 0.1 μM. It had no significant effect on guinea pig ventricular action potentials at concentrations of ≤3 μM. These results demonstrate that equol inhibits several cardiac K+ currents at relatively high concentrations, whereas it increases BKCa current at very low concentrations, suggesting that equol is a safe drug candidate for treating patients with cerebral vascular disorders.
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Wang Y, Sun HY, Liu YG, Song Z, She G, Xiao GS, Wang Y, Li GR, Deng XL. Tyrphostin AG556 increases the activity of large conductance Ca 2+ -activated K + channels by inhibiting epidermal growth factor receptor tyrosine kinase. J Cell Mol Med 2017; 21:1826-1834. [PMID: 28294531 PMCID: PMC5571560 DOI: 10.1111/jcmm.13103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 12/28/2016] [Indexed: 01/08/2023] Open
Abstract
The present study was designed to investigate whether large conductance Ca2+‐activated K+ (BK) channels were regulated by epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase. BK current and channel tyrosine phosphorylation level were measured in BK‐HEK 293 cells expressing both functional α‐subunits and the auxiliary β1‐subunits using electrophysiology, immunoprecipitation and Western blotting approaches, respectively, and the function of rat cerebral basilar arteries was determined with a wire myography system. We found that BK current in BK‐HEK 293 cells was increased by the broad spectrum protein tyrosine kinase (PTK) inhibitor genistein and the selective EGFR tyrosine kinase inhibitor AG556, one of the known tyrphostin. The effect of genistein or AG556 was antagonized by the protein tyrosine phosphatase (PTP) inhibitor orthovanadate. On the other hand, orthovanadate or EGF decreased BK current, and the effect was counteracted by AG556. The tyrosine phosphorylation level of BK channels (α‐ and β1‐subunits) was increased by EGF and orthovanadate, while decreased by genistein and AG556, and the reduced tyrosine phosphorylation of BK channels by genistein or AG556 was reversed by orthovanadate. Interestingly, AG556 induced a remarkable enhancement of BK current in rat cerebral artery smooth muscle cells and relaxation of pre‐contracted rat cerebral basilar arteries with denuded endothelium, and these effects were antagonized by the BK channel blocker paxilline or orthovanadate. These results demonstrate that tyrosine phosphorylation of BK channels by EGFR kinase decreases the channel activity, and inhibition of EGFR kinase by AG556 enhances the channel activity and dilates rat cerebral basilar arteries.
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Affiliation(s)
- Yan Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ying-Guang Liu
- Institute of Basic Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi, China
| | - Zheng Song
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Gang She
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Gui-Rong Li
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Xiu-Ling Deng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.,Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
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Xiao GS, Zhang YH, Wu W, Sun HY, Wang Y, Li GR. Genistein and tyrphostin AG556 decrease ultra-rapidly activating delayed rectifier K + current of human atria by inhibiting EGF receptor tyrosine kinase. Br J Pharmacol 2017; 174:454-467. [PMID: 28072464 DOI: 10.1111/bph.13710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 12/16/2016] [Accepted: 01/05/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The ultra-rapidly activating delayed rectifier K+ current IKur (encoded by Kv 1.5 or KCNA5) plays an important role in human atrial repolarization. The present study investigates the regulation of this current by protein tyrosine kinases (PTKs). EXPERIMENTAL APPROACH Whole-cell patch voltage clamp technique and immunoprecipitation and Western blotting analysis were used to investigate whether the PTK inhibitors genistein, tyrphostin AG556 (AG556) and PP2 regulate human atrial IKur and hKv1.5 channels stably expressed in HEK 293 cells. KEY RESULTS Human atrial IKur was decreased by genistein (a broad-spectrum PTK inhibitor) and AG556 (a highly selective EGFR TK inhibitor) in a concentration-dependent manner. Inhibition of IKur induced by 30 μM genistein or 10 μM AG556 was significantly reversed by 1 mM orthovanadate (a protein tyrosine phosphatase inhibitor). Similar results were observed in HEK 293 cells stably expressing hKv 1.5 channels. On the other hand, the Src family kinase inhibitor PP2 (1 μM) slightly enhanced IKur and hKv 1.5 current, and the current increase was also reversed by orthovanadate. Immunoprecipitation and Western blotting analysis showed that genistein, AG556, and PP2 decreased tyrosine phosphorylation of hKv 1.5 channels and that the decrease was countered by orthovanadate. CONCLUSION AND IMPLICATIONS The PTK inhibitors genistein and AG556 decrease human atrial IKur and cloned hKv 1.5 channels by inhibiting EGFR TK, whereas the Src kinase inhibitor PP2 increases IKur and hKv 1.5 current. These results imply that EGFR TK and the soluble Src kinases may have opposite effects on human atrial IKur .
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Affiliation(s)
- Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yan-Hui Zhang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wei Wu
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China
| | - Gui-Rong Li
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, Fujian, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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Liu H, Yang L, Chen KH, Sun HY, Jin MW, Xiao GS, Wang Y, Li GR. SKF-96365 blocks human ether-à-go-go-related gene potassium channels stably expressed in HEK 293 cells. Pharmacol Res 2015; 104:61-9. [PMID: 26689773 DOI: 10.1016/j.phrs.2015.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/19/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022]
Abstract
SKF-96365 is a TRPC channel antagonist commonly used to characterize the potential functions of TRPC channels in different systems, which was recently reported to induce QTc prolongation on ECG by inhibiting TRPC channels. The present study investigates whether the blockade of cardiac repolarization currents would be involved in the increase of QTc interval. Cardiac repolarization currents were recorded in HEK 293 cells stably expressing human ether-à-go-go-related gene potassium (hERG or hKv11.1) channels, hKCNQ1/hKCNE1 channels (IKs) or hKir2.1 channels and cardiac action potentials were recorded in guinea pig ventricular myocytes using a whole-cell patch technique. The potential effect of SKF-96365 on QT interval was evaluated in ex vivo guinea pig hearts. It was found that SKF-96365 inhibited hERG current in a concentration-dependent manner (IC50, 3.4μM). The hERG mutants S631A in the pore helix and F656V of the S6 region reduced the inhibitory sensitivity with IC50s of 27.4μM and 11.0μM, suggesting a channel pore blocker. In addition, this compound inhibited IKs and hKir2.1currents with IC50s of 10.8 and 8.7μM. SKF-96365 (10μM) significantly prolonged ventricular APD90 in guinea pig ventricular myocytes and QTc interval in ex vivo guinea pig hearts. These results indicate that the TRPC channel antagonist SKF-96365 exerts blocking effects on hERG, IKs, and hKir2.1 channels. Prolongation of ventricular APD and QT interval is related to the inhibition of multiple repolarization potassium currents, especially hERG channels.
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Affiliation(s)
- Hui Liu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Lei Yang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Kui-Hao Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Hai-Ying Sun
- Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Man-Wen Jin
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China.
| | - Gui-Rong Li
- Departments of Physiology and Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, China; Xiamen Cardiovascular Hospital, Medical College of Xiamen University, Xiamen, China.
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Abstract
Abstract
Background:
Propofol is widely used clinically for the induction and maintenance of anesthesia. Clinical case reports have shown that propofol has an antiatrial tachycardia/fibrillation effect; however, the related ionic mechanisms are not fully understood. The current study investigates the effects of propofol on human cardiac potassium channels.
Methods:
The whole cell patch voltage clamp technique was used to record transient outward potassium current (Ito) and ultrarapidly activating delayed rectifier potassium current (IKur) in human atrial myocytes and hKv1.5, human ether-à-go-go-related gene (hERG), and hKCNQ1/hKCNE1 channels stably expressed in HEK 293 cells. Current clamp mode was used to record action potentials in human atrial myocytes.
Results:
In human atrial myocytes, propofol inhibited Ito in a concentration-dependent manner (IC50 = 33.5 ± 2.0 μM for peak current, n = 6) by blocking open channels without affecting the voltage-dependent kinetics or the recovery time constant; propofol decreased IKur (IC50 = 35.3 ± 1.9 μM, n = 6) in human atrial myocytes and inhibited hKv1.5 current expressed in HEK 293 cells by preferentially binding to the open channels. Action potential duration at 90% repolarization was slightly prolonged by 30 μM propofol in human atrial myocytes. In addition, propofol also suppressed hERG and hKCNQ1/hKCNE1 channels expressed in HEK 293 cells.
Conclusion:
Propofol inhibits multiple human cardiac potassium channels, including human atrial Ito and IKur, as well as hKv1.5, hERG, and hKCNQ1/hKCNE1 channels stably expressed in HEK 293 cells, and slightly prolongs human atrial action potential duration, which may contribute to the antiatrial tachycardia/fibrillation effects observed in patients who receive propofol.
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Yu CC, Ai T, Weiss JN, Chen PS. Apamin does not inhibit human cardiac Na+ current, L-type Ca2+ current or other major K+ currents. PLoS One 2014; 9:e96691. [PMID: 24798465 PMCID: PMC4010514 DOI: 10.1371/journal.pone.0096691] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/10/2014] [Indexed: 12/03/2022] Open
Abstract
Background Apamin is commonly used as a small-conductance Ca2+-activated K+ (SK) current inhibitor. However, the specificity of apamin in cardiac tissues remains unclear. Objective To test the hypothesis that apamin does not inhibit any major cardiac ion currents. Methods We studied human embryonic kidney (HEK) 293 cells that expressed human voltage-gated Na+, K+ and Ca2+ currents and isolated rabbit ventricular myocytes. Whole-cell patch clamp techniques were used to determine ionic current densities before and after apamin administration. Results Ca2+ currents (CACNA1c+CACNB2b) were not affected by apamin (500 nM) (data are presented as median [25th percentile;75th percentile] (from –16 [–20;–10] to –17 [–19;–13] pA/pF, P = NS), but were reduced by nifedipine to –1.6 [–3.2;–1.3] pA/pF (p = 0.008). Na+ currents (SCN5A) were not affected by apamin (from –261 [–282;–145] to –268 [–379;–132] pA/pF, P = NS), but were reduced by flecainide to –57 [–70;–47] pA/pF (p = 0.018). None of the major K+ currents (IKs, IKr, IK1 and Ito) were inhibited by 500 nM of apamin (KCNQ1+KCNE1, from 28 [20]; [37] to 23 [18]; [32] pA/pF; KCNH2+KCNE2, from 28 [24]; [30] to 27 [24]; [29] pA/pF; KCNJ2, from –46 [–48;–40] to –46 [–51;–35] pA/pF; KCND3, from 608 [505;748] to 606 [454;684]). Apamin did not inhibit the INa or ICaL in isolated rabbit ventricular myocytes (INa, from –67 [–75;–59] to –68 [–71;–59] pA/pF; ICaL, from –16 [–17;–14] to –14 [–15;–13] pA/pF, P = NS for both). Conclusions Apamin does not inhibit human cardiac Na+ currents, L-type Ca2+ currents or other major K+ currents. These findings indicate that apamin is a specific SK current inhibitor in hearts as well as in other organs.
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Affiliation(s)
- Chih-Chieh Yu
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Integrated Diagnostic & Therapeutics, National Taiwan University, Taipei, Taiwan
| | - Tomohiko Ai
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Molecular Pathogenesis, Division of Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - James N. Weiss
- Cardiovascular Research Laboratory, Departments of Medicine (Cardiology) and Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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EGFR tyrosine kinase regulates human small-conductance Ca2+-activated K+ (hSKCa1) channels expressed in HEK-293 cells. Biochem J 2013; 452:121-9. [PMID: 23496660 DOI: 10.1042/bj20121324] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
SKCa (small-conductance Ca(2+)-activated K(+)) channels are widely distributed in different tissues, including the brain, pancreatic islets and myocardium and play an important role in controlling electrical activity and cellular functions. However, intracellular signal modulation of SKCa channels is not fully understood. The present study was designed to investigate the potential regulation of hSKCa1 (human SKCa1) channels by PTKs (protein tyrosine kinases) in HEK (human embryonic kidney)-293 cells expressing the hSKCa1 (KCNN1) gene using approaches of whole-cell patch voltage-clamp, immunoprecipitation, Western blotting and mutagenesis. We found that the hSKCa1 current was inhibited by the broad-spectrum PTK inhibitor genistein, the selective EGFR (epidermal growth factor receptor) kinase inhibitors T25 (tyrphostin 25) and AG556 (tyrphostin AG 556), but not by the Src-family kinases inhibitor PP2. The inhibitory effect of these PTK inhibitors was significantly antagonized by the PTP (protein tyrosine phosphatase) inhibitor orthovanadate. The tyrosine phosphorylation level of hSKCa1 channels was reduced by genistein, T25 or AG556. The reduced tyrosine phosphorylation was countered by orthovanadate. Interestingly, the Y109F mutant hSKCa1 channel lost the inhibitory response to T25 or AG556, and showed a dramatic reduction in tyrosine phosphorylation levels and a reduced current density. These results demonstrate the novel information that hSKCa1 channels are inhibited by genistein, T25 and AG556 via EGFR tyrosine kinase inhibition, which is related to the phosphorylation of Tyr(109) in the N-terminus. This effect may affect electrical activity and cellular functions in brain, pancreatic islets and myocardium.
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Xu XH, Sun HY, Zhang YH, Wu W, Chen KH, Liu Y, Deng CY, Yu XY, Jin MW, Li GR. Allitridi inhibits multiple cardiac potassium channels expressed in HEK 293 cells. PLoS One 2012; 7:e51550. [PMID: 23272117 PMCID: PMC3522701 DOI: 10.1371/journal.pone.0051550] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 11/02/2012] [Indexed: 02/02/2023] Open
Abstract
Allitridi (diallyl trisulfide) is an active compound (volatile oil) from garlic. The previous studies reported that allitridi had anti-arrhythmic effect. The potential ionic mechanisms are, however, not understood. The present study was designed to determine the effects of allitridi on cardiac potassium channels expressed in HEK 293 cells using a whole-cell patch voltage-clamp technique and mutagenesis. It was found that allitridi inhibited hKv4.3 channels (IC50 = 11.4 µM) by binding to the open channel, shifting availability potential to hyperpolarization, and accelerating closed-state inactivation of the channel. The hKv4.3 mutants T366A, T367A, V392A, and I395A showed a reduced response to allitridi with IC50s of 35.5 µM, 44.7 µM, 23.7 µM, and 42.4 µM. In addition, allitridi decreased hKv1.5, hERG, hKCNQ1/hKCNE1 channels stably expressed in HEK 293 cells with IC50s of 40.2 µM, 19.6 µM and 17.7 µM. However, it slightly inhibited hKir2.1 current (100 µM, inhibited by 9.8% at −120 mV). Our results demonstrate for the first time that allitridi preferably blocks hKv4.3 current by binding to the open channel at T366 and T367 of P-loop helix, and at V392 and I395 of S6 domain. It has a weak inhibition of hKv1.5, hERG, and hKCNQ1/hKCNE1 currents. These effects may account for its anti-arrhythmic effect observed in experimental animal models.
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Affiliation(s)
- Xiao-Hui Xu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Yan-Hui Zhang
- Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Wei Wu
- Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Kui-Hao Chen
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Liu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun-Yu Deng
- Research Centre, Guangdong General Hospital, Guangzhou, China
| | - Xi-Yong Yu
- Research Centre, Guangdong General Hospital, Guangzhou, China
| | - Man-Wen Jin
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (GRL); (MWJ)
| | - Gui-Rong Li
- Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
- Department of Physiology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
- * E-mail: (GRL); (MWJ)
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Wrobel E, Tapken D, Seebohm G. The KCNE Tango - How KCNE1 Interacts with Kv7.1. Front Pharmacol 2012; 3:142. [PMID: 22876232 PMCID: PMC3410610 DOI: 10.3389/fphar.2012.00142] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 06/29/2012] [Indexed: 12/23/2022] Open
Abstract
The classical tango is a dance characterized by a 2/4 or 4/4 rhythm in which the partners dance in a coordinated way, allowing dynamic contact. There is a surprising similarity between the tango and how KCNE β-subunits "dance" to the fast rhythm of the cell with their partners from the Kv channel family. The five KCNE β-subunits interact with several members of the Kv channels, thereby modifying channel gating via the interaction of their single transmembrane-spanning segment, the extracellular amino terminus, and/or the intracellular carboxy terminus with the Kv α-subunit. Best studied is the molecular basis of interactions between KCNE1 and Kv7.1, which, together, supposedly form the native cardiac I(Ks) channel. Here we review the current knowledge about functional and molecular interactions of KCNE1 with Kv7.1 and try to summarize and interpret the tango of the KCNEs.
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Affiliation(s)
- Eva Wrobel
- Cation Channel Group, Department of Biochemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum Bochum, Germany
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Zhang YH, Wu W, Sun HY, Deng XL, Cheng LC, Li X, Tse HF, Lau CP, Li GR. Modulation of human cardiac transient outward potassium current by EGFR tyrosine kinase and Src-family kinases. Cardiovasc Res 2011; 93:424-33. [PMID: 22198508 DOI: 10.1093/cvr/cvr347] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
AIMS The human cardiac transient outward K(+) current I(to) (encoded by Kv4.3 or KCND3) plays an important role in phase 1 rapid repolarization of cardiac action potentials in the heart. However, modulation of I(to) by intracellular signal transduction is not fully understood. The present study was therefore designed to determine whether/how human atrial I(to) and hKv4.3 channels stably expressed in HEK 293 cells are regulated by protein tyrosine kinases (PTKs). METHODS AND RESULTS Whole-cell patch voltage-clamp, immunoprecipitation, western blotting, and site-directed mutagenesis approaches were employed in the present study. We found that human atrial I(to) was inhibited by the broad-spectrum PTK inhibitor genistein, the selective epidermal growth factor receptor (EGFR) kinase inhibitor AG556, and the Src-family kinases inhibitor PP2. The inhibitory effect was countered by the protein tyrosine phosphatase inhibitor orthovanadate. In HEK 293 cells stably expressing human KCND3, genistein, AG556, and PP2 significantly reduced the hKv4.3 current, and the reduction was antagonized by orthovanadate. Interestingly, orthovanadate also reversed the reduced tyrosine phosphorylation level of hKv4.3 channels by genistein, AG556, or PP2. Mutagenesis revealed that the hKv4.3 mutant Y136F lost the inhibitory response to AG556, while Y108F lost response to PP2. The double-mutant Y108F-Y136F hKv4.3 channels showed no response to either AG556 or PP2. CONCLUSION Our results demonstrate that human atrial I(to) and cloned hKv4.3 channels are modulated by EGFR kinase via phosphorylation of the Y136 residue and by Src-family kinases via phosphorylation of the Y108 residue; tyrosine phosphorylation of the channel may be involved in regulating cardiac electrophysiology.
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Affiliation(s)
- Yan-Hui Zhang
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, L4-59, Laboratory Block, FMB, 21 Sassoon Road, Pokfulam, Hong Kong, China
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Zhang DY, Zhang YH, Sun HY, Lau CP, Li GR. Epidermal growth factor receptor tyrosine kinase regulates the human inward rectifier potassium K(IR)2.3 channel, stably expressed in HEK 293 cells. Br J Pharmacol 2011; 164:1469-78. [PMID: 21486282 PMCID: PMC3221101 DOI: 10.1111/j.1476-5381.2011.01424.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 03/05/2011] [Accepted: 04/04/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The detailed molecular modulation of inward rectifier potassium channels (including the K(IR) 2.3 channel) is not fully understood. The present study was designed to determine whether human K(IR) 2.3 (K(IR) 2.3) channels were regulated by protein tyrosine kinases (PTKs). EXPERIMENTAL APPROACH Whole-cell patch voltage-clamp, immunoprecipitation, Western blot analysis and site-directed mutagenesis were employed to determine the potential PTK phosphorylation of Kir2.3 current in HEK 293 cells stably expressing Kir2.3 gene. KEY RESULTS The broad-spectrum PTK inhibitor genistein (10 µM) and the selective epidermal growth factor (EGF) kinase inhibitor AG556 (10 µM) reversibly decreased K(IR) 2.3 current and the effect was reversed by the protein tyrosine phosphatase inhibitor, orthovanadate (1 mM). Although EGF (100 ng·mL(-1) ) and orthovanadate enhanced K(IR) 2.3 current, this effect was antagonized by AG556. However, the Src-family tyrosine kinase inhibitor PP2 (10 µM) did not inhibit K(IR) 2.3 current. Tyrosine phosphorylation of K(IR) 2.3 channels was decreased by genistein or AG556, and was increased by EGF or orthovanadate. The decrease of tyrosine phosphorylation of K(IR) 2.3 channels by genistein or AG556 was reversed by orthovanadate or EGF. Interestingly, the response of K(IR) 2.3 channels to EGF or AG556 was lost in the K(IR) 2.3 Y234A mutant channel. CONCLUSION AND IMPLICATIONS These results demonstrate that the EGF receptor tyrosine kinase up-regulates the K(IR) 2.3 channel via phosphorylation of the Y234 residue of the WT protein. This effect may be involved in the endogenous regulation of cellular electrical activity.
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Affiliation(s)
- De-Yong Zhang
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
| | - Yan-Hui Zhang
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
| | - Hai-Ying Sun
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
| | - Chu-Pak Lau
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
| | - Gui-Rong Li
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
- Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong SAR, China
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Wu W, Dong MQ, Wu XG, Sun HY, Tse HF, Lau CP, Li GR. Human ether-à-go-go gene potassium channels are regulated by EGFR tyrosine kinase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:282-9. [PMID: 22061963 DOI: 10.1016/j.bbamcr.2011.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/21/2011] [Accepted: 10/24/2011] [Indexed: 11/15/2022]
Abstract
Human ether á-go-go gene potassium channels (hEAG1 or Kv10.1) are expressed in brain and various human cancers and play a role in neuronal excitement and tumor progression. However, the functional regulation of hEAG channels by signal transduction is not fully understood. The present study was therefore designed to investigate whether hEAG1 channels are regulated by protein tyrosine kinases (PTKs) in HEK 293 cells stably expressing hEAG1 gene using whole-cell patch voltage-clamp, immunoprecipitation, Western blot, and mutagenesis approaches. We found that the selective epidermal growth factor receptor (EGFR) kinase inhibitor AG556 (10 μM), but not the platelet growth factor receptor (PDGFR) kinase inhibitor AG1295 (10 μM) or the Src-family inhibitor PP2 (10 μM), can inhibit hEAG1 current, and the inhibitory effect can be reversed by the protein tyrosine phosphatase (PTP) inhibitor orthovanadate. Immunoprecipitation and Western blot analysis revealed that tyrosine phosphorylation level of hEAG1 channels was reduced by AG556, and the reduction was significantly countered by orthovanadate. The hEAG1 mutants Y90A, Y344A and Y485A, but not Y376A and Y479A, exhibited reduced response to AG556. Interestingly, the inhibition effect of AG556 was lost in triple mutant hEAG1 channels at Y90, Y344, and Y485 with alanine. These results demonstrate for the first time that hEAG1 channel activity is regulated by EGFR kinase at the tyrosine residues Tyr90, Try344, and Try485. This effect is likely involved in regulating neuronal activity and/or tumor growth.
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Affiliation(s)
- Wei Wu
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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Zhang DY, Wu W, Deng XL, Lau CP, Li GR. Genistein and tyrphostin AG556 inhibit inwardly-rectifying Kir2.1 channels expressed in HEK 293 cells via protein tyrosine kinase inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1993-9. [DOI: 10.1016/j.bbamem.2011.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 04/13/2011] [Accepted: 04/29/2011] [Indexed: 11/28/2022]
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Wallace JL, Gow IF, Warnock M. The life and death of breast cancer cells: proposing a role for the effects of phytoestrogens on potassium channels. J Membr Biol 2011; 242:53-67. [PMID: 21728044 DOI: 10.1007/s00232-011-9376-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 06/20/2011] [Indexed: 10/18/2022]
Abstract
Changes in the regulation of potassium channels are increasingly implicated in the altered activity of breast cancer cells. Increased or reduced expression of a number of K(+) channels have been identified in numerous breast cancer cell lines and cancerous tissue biopsy samples, compared to normal tissue, and are associated with tumor formation and spread, enhanced levels of proliferation, and resistance to apoptotic stimuli. Through knockout or silencing of K(+) channel genes, and use of specific or more broad pharmacologic K(+) channel blockers, the growth of numerous cell lines, including breast cancer cells, has been modified. In this manner it has been proposed that in MCF7 breast cancer cells proliferation appears to be regulated by the activity of a number of K(+) channels, including the Ca(2+) activated K(+) channels, and the voltage-gated K(+) channels hEAG and K(v)1.1. The effect of phytoestrogens on K(+) channels has not been extensively studied but yields some interesting results. In a number of cell lines the phytoestrogen genistein inhibits K(+) current through several channels including K(v)1.3 and hERG. Where it has been used, structurally similar daidzein has little or no effect on K(+) channel activity. Since many K(+) channels have roles in proliferation and apoptosis in breast cancer cells, the impact of K(+) channel regulation by phytoestrogens is of potentially great relevance.
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Affiliation(s)
- Joanne L Wallace
- School of Health Sciences, Queen Margaret University, Musselburgh, Edinburgh, Scotland, UK.
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Li GR, Dong MQ. Pharmacology of Cardiac Potassium Channels. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:93-134. [DOI: 10.1016/s1054-3589(10)59004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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