1
|
Renkhold L, Kollmann R, Inderwiedenstraße L, Kienitz MC. PKC-isoform specific regulation of receptor desensitization and KCNQ1/KCNE1 K + channel activity by mutant α 1B-adrenergic receptors. Cell Signal 2021; 91:110228. [PMID: 34958868 DOI: 10.1016/j.cellsig.2021.110228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/25/2022]
Abstract
Activation of a specific protein kinase C (PKC) isoform during stimulation of Gq protein-coupled receptors (GqPCRs) is determined by homologous receptor desensitization that controls the spatiotemporal formation of downstream Gq signalling molecules. Furthermore, GqPCR-activated PKC isoforms specifically regulate receptor activity via a negative feedback mechanism. In the present study, we investigated the contribution of several phosphorylation sites in the α1B-adrenergic receptor (α1B-AR) for PKC and G protein coupled receptor kinase 2 (GRK2) to homologous receptor desensitization and effector modulation. We analyzed signalling events downstream to human wildtype α1B-ARs and α1B-ARs lacking PKC or GRK2 phosphorylation sites (Δ391-401, α1B-ΔPKC-AR and Δ402-520, α1B-ΔGRK-AR) by means of FRET-based biosensors in HEK293 that served as online-assays of receptor activity. K+ currents through KCNQ1/KCNE1 channels (IKs), which are regulated by both phosphatidylinositol 4,5-bisphosphate (PIP2)-depletion and/or phosphorylation by PKC, were measured as a functional readout of wildtype and mutant α1B-AR receptor activity. As a novel finding, we provide evidence that deletion of PKC and GRK2 phosphorylation sites in α1B-ARs abrogates the contribution of PKCα to homologous receptor desensitization. Instead, the time course of mutant receptor activity was specifically modulated by PKCβ. Mutant α1B-ARs displayed pronounced homologous receptor desensitization that was abolished by PKCβ-specific pharmacological inhibitors. IKs modulation during stimulation of wildtype and mutant α1B-ARs displayed transient inhibition and current facilitation after agonist withdrawal with reduced capability of mutant α1B-ARs to induce IKs inhibition. Pharmacological inhibition of the PKCβ isoform did not augment IKs reduction by mutant α1B-ARs, but shifted IKs modulation towards current facilitation. Coexpression of an inactive (dominant-negative) PKCδ isoform (DN-PKCδ) abolished IKs facilitation in α1B-ΔGRK-AR-expressing cells, but not in α1B-ΔPKC-AR-expressing cells. The data indicate that the differential modulation of IKs activity by α1B-ΔGRK- and α1B-ΔPKC-receptors is attributed to the activation of entirely distinct novel PKC isoforms. To summarize, specific phosphorylation sites within the wildtype and mutant α1B-adrenergic receptors are targeted by different PKC isoforms, resulting in differential regulation of receptor desensitization and effector function.
Collapse
Affiliation(s)
- Lina Renkhold
- Klinik für Hautkrankheiten, Universitätsklinikum Münster, Von-Esmarch-Str. 58, D-48149 Münster, Deutschland, Germany
| | - Rike Kollmann
- Department of Cellular Physiology, Institute of Physiology, Ruhr University Bochum, Universitätsstrasse 150, D-44801 Bochum, Germany
| | - Leonie Inderwiedenstraße
- Department of Cellular Physiology, Institute of Physiology, Ruhr University Bochum, Universitätsstrasse 150, D-44801 Bochum, Germany
| | - Marie-Cecile Kienitz
- Department of Cellular Physiology, Institute of Physiology, Ruhr University Bochum, Universitätsstrasse 150, D-44801 Bochum, Germany.
| |
Collapse
|
2
|
Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
Collapse
Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| |
Collapse
|
3
|
Smyrnias I, Goodwin N, Wachten D, Skogestad J, Aronsen JM, Robinson EL, Demydenko K, Segonds-Pichon A, Oxley D, Sadayappan S, Sipido K, Bootman MD, Roderick HL. Contractile responses to endothelin-1 are regulated by PKC phosphorylation of cardiac myosin binding protein-C in rat ventricular myocytes. J Mol Cell Cardiol 2018; 117:1-18. [DOI: 10.1016/j.yjmcc.2018.02.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/02/2018] [Accepted: 02/16/2018] [Indexed: 01/07/2023]
|
4
|
Gou X, Wang W, Zou S, Qi Y, Xu Y. Protein kinase C epsilon mediates the inhibition of angiotensin II on the slowly activating delayed-rectifier potassium current through channel phosphorylation. J Mol Cell Cardiol 2018; 116:165-174. [PMID: 29452158 DOI: 10.1016/j.yjmcc.2018.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 01/25/2018] [Accepted: 02/12/2018] [Indexed: 01/14/2023]
Abstract
The slowly activating delayed rectifier K+ current (IKs) is one of the main repolarizing currents in the human heart. Evidence has shown that angiotensin II (Ang II) regulates IKs through the protein kinase C (PKC) pathway, but the related results are controversial. This study was designed to identify PKC isoenzymes involved in the regulation of IKs by Ang II and the underlying molecular mechanism. The whole-cell patch-clamp technique was used to record IKs in isolated guinea pig ventricular cardiomyocytes and in human embryonic kidney (HEK) 293 cells co-transfected with human KCNQ1/KCNE1 genes and Ang II type 1 receptor genes. Ang II inhibited IKs in a concentration-dependent manner in native cardiomyocytes. A broad PKC inhibitor Gö6983 (not inhibiting PKCε) and a selective cPKC inhibitor Gö6976 did not affect the inhibitory action of Ang II. In contrast, the inhibition was significantly attenuated by PKCε-selective peptide inhibitor εV1-2. However, direct activation of PKC by phorbol 12-myristate 13-acetate (PMA) increased the cloned human IKs in HEK293 cells. Similarly, the cPKC peptide activator significantly enhanced the current. In contrast, the PKCε peptide activator inhibited the current. Further evidence showed that PKCε knockdown by siRNA antagonized the Ang II-induced inhibition on KCNQ1/KCNE1 current, whereas knockdown of cPKCs (PKCα and PKCβ) attenuated the potentiation of the current by PMA. Moreover, deletion of four putative phosphorylation sites in the C-terminus of KCNQ1 abolished the action of PMA. Mutation of two putative phosphorylation sites in the N-terminus of KCNQ1 and one site in KCNE1 (S102) blocked the inhibition of Ang II. Our results demonstrate that PKCε isoenzyme mediates the inhibitory action of Ang II on IKs and by phosphorylating distinct sites in KCNQ1/KCNE1, cPKC and PKCε isoenzymes produce the contrary regulatory effects on the channel. These findings have provided new insight into the molecular mechanism underlying the modulation of the KCNQ1/KCNE1 channel.
Collapse
Affiliation(s)
- Xiangbo Gou
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Province, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang 050017, China; Department of Pharmacology, North China University of Science and Technology, Tangshan 063210, China
| | - Wenying Wang
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Province, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang 050017, China
| | - Sihao Zou
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Province, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang 050017, China
| | - Yajuan Qi
- Department of Pharmacology, North China University of Science and Technology, Tangshan 063210, China
| | - Yanfang Xu
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Province, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang 050017, China.
| |
Collapse
|
5
|
Effect of Exogenous Extracellular Nicotinamide Adenine Dinucleotide (NAD⁺) on Bioelectric Activity of the Pacemaker and Conduction System of the Heart. Bull Exp Biol Med 2015; 159:188-91. [PMID: 26085350 DOI: 10.1007/s10517-015-2919-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Indexed: 10/23/2022]
Abstract
In rat sinoatrial node, NAD(+) (10 μM) reduced the rate of spontaneous action potentials, duration of action potentials, and the velocity of slow diastolic depolarization, but the rate of action potential front propagation increases. In passed rabbit Purkinje fibers, NAD(+) (10 μM) reduced the duration of action potentials. Under conditions of spontaneous activity of Purkinje fibers, NAD(+) reduced the fi ring rate and the rate of slow diastolic depolarization. The effects of extracellular NAD(+) on bioelectric activity of the pacemaker (sinoatrial node) and conduction system of the heart (Purkinje fibers) are probably related to activation of P1 and P2 purinoceptors.
Collapse
|
6
|
Zheng C, Deng QQ, Liu LL, Wang MY, Zhang G, Sheng WL, Weng SJ, Yang XL, Zhong YM. Orexin-A differentially modulates AMPA-preferring responses of ganglion cells and amacrine cells in rat retina. Neuropharmacology 2015; 93:80-93. [PMID: 25656479 DOI: 10.1016/j.neuropharm.2015.01.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/22/2014] [Accepted: 01/20/2015] [Indexed: 01/18/2023]
Abstract
By activating their receptors (OX1R and OX2R) orexin-A/B regulate wake/sleeping states, feeding behaviors, but the function of these peptides in the retina remains unknown. Using patch-clamp recordings and calcium imaging in rat isolated retinal cells, we demonstrated that orexin-A suppressed α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-preferring receptor-mediated currents (AMPA-preferring currents) in ganglion cells (GCs) through OX1R, but potentiated those in amacrine cells (ACs) through OX2R. Consistently, in rat retinal slices orexin-A suppressed light-evoked AMPA-preferring receptor-mediated excitatory postsynaptic currents in GCs, but potentiated those in ACs. Intracellular dialysis of GDP-β-S or preincubation with the Gi/o inhibitor pertussis toxin (PTX) abolished both the effects. Either cAMP/the protein kinase A (PKA) inhibitor Rp-cAMP or cGMP/the PKG blocker KT5823 failed to alter the orexin-A effects. Whilst both of them involved activation of protein kinase C (PKC), the effects on GCs and ACs were respectively eliminated by the phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor and phosphatidylcholine (PC)-PLC inhibitor. Moreover, in GCs orexin-A increased [Ca(2+)]i and the orexin-A effect was blocked by intracellular Ca(2+)-free solution and by inositol 1,4,5-trisphosphate (IP3) receptor antagonists. In contrast, orexin-A did not change [Ca(2+)]i in ACs and the orexin-A effect remained in intracellular or extracellular Ca(2+)-free solution. We conclude that a distinct Gi/o/PI-PLC/IP3/Ca(2+)-dependent PKC signaling pathway, following the activation of OX1R, is likely responsible for the orexin-A effect on GCs, whereas a Gi/o/PC-PLC/Ca(2+)-independent PKC signaling pathway, following the activation of OX2R, mediates the orexin-A effect on ACs. These two actions of orexin-A, while working in concert, provide a characteristic way for modulating information processing in the inner retina.
Collapse
Affiliation(s)
- Chao Zheng
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China; Cell Electrophysiology Laboratory, Wannan Medical College, 22 West Wenchang Road, Wuhu, Anhui 241002, China
| | - Qin-Qin Deng
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Lei-Lei Liu
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Meng-Ya Wang
- Cell Electrophysiology Laboratory, Wannan Medical College, 22 West Wenchang Road, Wuhu, Anhui 241002, China
| | - Gong Zhang
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Wen-Long Sheng
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Shi-Jun Weng
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Xiong-Li Yang
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
| | - Yong-Mei Zhong
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
| |
Collapse
|
7
|
O-Uchi J, Rice JJ, Ruwald MH, Parks XX, Ronzier E, Moss AJ, Zareba W, Lopes CM. Impaired IKs channel activation by Ca(2+)-dependent PKC shows correlation with emotion/arousal-triggered events in LQT1. J Mol Cell Cardiol 2014; 79:203-11. [PMID: 25479336 DOI: 10.1016/j.yjmcc.2014.11.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 10/23/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND The most common inherited cardiac arrhythmia, LQT1, is due to IKs potassium channel mutations and is linked to high risk of adrenergic-triggered cardiac events. We recently showed that although exercise-triggered events are very well treated by ß-blockers for these patients, acute arousal-triggered event rate were not significantly reduced after beta-blocker treatment, suggesting that the mechanisms underlying arousal-triggered arrhythmias may be different from those during exercise. IKs is strongly regulated by β-adrenergic receptor (β-AR) signaling, but little is known about the role of α1-AR-mediated regulation. METHODS AND RESULTS Here we show, using a combination of cellular electrophysiology and computational modeling, that IKs phosphorylation and α1-AR regulation via activation of calcium-dependent PKC isoforms (cPKC) may be a key mechanism to control channel voltage-dependent activation and consequently action potential duration (APD) in response to adrenergic-stimulus. We show that simulated mutation-specific combined adrenergic effects (β+α) on APD were strongly correlated to acute stress-triggered cardiac event rate for patients while β-AR effects alone were not. CONCLUSION We were able to show that calcium-dependent PKC signaling is key to normal QT shortening during acute arousal and when impaired, correlates with increased rate of sudden arousal-triggered cardiac events. Our study suggests that the acute α1-AR-cPKC regulation of IKs is important for QT shortening in "fight-or-flight" response and is linked to decreased risk of sudden emotion/arousal-triggered cardiac events in LQT1 patients.
Collapse
Affiliation(s)
- Jin O-Uchi
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - J Jeremy Rice
- Functional Genomics and Systems Biology Group, IBM T.J. Watson Research Center, New York, USA
| | - Martin H Ruwald
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Xiaorong Xu Parks
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Elsa Ronzier
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Arthur J Moss
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Wojciech Zareba
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA
| | - Coeli M Lopes
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA.
| |
Collapse
|
8
|
De Mello WC. Intracellular renin alters the electrical properties of the intact heart ventricle of adult Sprague Dawley rats. ACTA ACUST UNITED AC 2013; 181:45-9. [PMID: 23318498 DOI: 10.1016/j.regpep.2012.12.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 11/20/2012] [Accepted: 12/17/2012] [Indexed: 11/26/2022]
Abstract
UNLABELLED The influence of intracellular renin injection on the electrical properties of the intact left ventricle from adult Sprague Dawley rat heart was investigated. Intracellular renin injection was performed using intracellular microelectrodes filled with solution containing renin (120pM). Pressure pulses (40-70psi) for short periods of time (20ms), were applied to the micropipette while recording the action potential simultaneously from the same fiber. The results indicated that intracellular renin caused a depolarization of ventricular fibers of 7.3±2±mV (n=38) (4 animals) (P<0.05) and a decrease of the action potential duration at 50% and at 90% repolarization, respectively. Moreover, the refractoriness was significantly decreased with consequent generation of triggered activity. The effect of intracellular renin was seen within 3min of enzyme injection. The shortening of the action potential was related to an increase of potassium current which was measured in isolated ventricular myocytes before and after intracellular dialysis of renin (10(-9)M) using a voltage whole cell clamp configuration. Valsartan (10(-8)M) dialyzed together with renin (120pM) into the cell decreased drastically the effect of renin on potassium current. An increment of potassium current was also found when intracellular renin was dialyzed into cardiomyocytes exposed to Krebs solution containing valsartan (10(-8)M) for 10min prior to renin administration. Bis-1 which is a specific inhibitor of PKC, abolished the effect of intracellular renin on potassium current. IN CONCLUSION intracellular renin decreases the action potential duration and cardiac refractoriness in the intact left ventricle of adult Sprague Dawley rats. The shortening of the action potential was related to an increase in total potassium current. The effect of renin on total potassium currents was inhibited by valsartan and by Bis-1. Implication for cardiac arrhythmias was discussed.
Collapse
Affiliation(s)
- Walmor C De Mello
- School of Medicine, Medical Sciences Campus, UPR, San Juan, PR 00936-5067, USA.
| |
Collapse
|
9
|
Si M, Xu J, Zhang F, Wang C, Du X, Zhang H. Involvement of Protein Kinase A and C in Norepinephrine- and Angiotensin II-Induced Modulation of Cardiac IKs. Pharmacology 2013; 92:217-26. [DOI: 10.1159/000354881] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/06/2013] [Indexed: 11/19/2022]
|
10
|
Signaling from the sympathetic nervous system regulates hematopoietic stem cell emergence during embryogenesis. Cell Stem Cell 2012; 11:554-66. [PMID: 23040481 PMCID: PMC3510442 DOI: 10.1016/j.stem.2012.07.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 04/25/2012] [Accepted: 07/02/2012] [Indexed: 02/02/2023]
Abstract
The first adult-repopulating hematopoietic stem cells (HSCs) emerge in the aorta-gonads-mesonephros (AGM) region of the embryo. We have recently identified the transcription factor Gata3 as being upregulated in this tissue specifically at the time of HSC emergence. We now demonstrate that the production of functional and phenotypic HSCs in the AGM is impaired in the absence of Gata3. Furthermore, we show that this effect on HSC generation is secondary to the role of Gata3 in the production of catecholamines, the mediators of the sympathetic nervous system (SNS), thus making these molecules key components of the AGM HSC niche. These findings demonstrate that the recently described functional interplay between the hematopoietic system and the SNS extends to the earliest stages of their codevelopment and highlight the fact that HSC development needs to be viewed in the context of the development of other organs.
Collapse
|
11
|
Makary S, Voigt N, Maguy A, Wakili R, Nishida K, Harada M, Dobrev D, Nattel S. Differential Protein Kinase C Isoform Regulation and Increased Constitutive Activity of Acetylcholine-Regulated Potassium Channels in Atrial Remodeling. Circ Res 2011; 109:1031-43. [DOI: 10.1161/circresaha.111.253120] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rationale:
Atrial fibrillation (AF) causes atrial-tachycardia remodeling (ATR), with enhanced constitutive acetylcholine-regulated K
+
current (I
KAChC
) contributing to action potential duration shortening and AF promotion. The underlying mechanisms are unknown.
Objective:
To evaluate the role of protein-kinase C (PKC) isoforms in ATR-induced I
KAChC
activation.
Methods and Results:
Cells from ATR-dogs (400-bpm atrial pacing for 1 week) were compared to control dog cells. In vitro tachypaced (TP; 3 Hz) canine atrial cardiomyocytes were compared to parallel 1-Hz paced cells. I
KAChC
single-channel activity was assessed in cell-attached and cell-free (inside-out) patches. Protein expression was assessed by immunoblot. In vitro TP activated I
KAChC
, mimicking effects of in vivo ATR. Discrepant effects of PKC activation and inhibition between control and ATR cells suggested isoform-selective effects and altered PKC isoform distribution. Conventional PKC isoforms (cPKC; including PKCα) inhibited, whereas novel isoforms (including PKCε) enhanced, acetylcholine-regulated K
+
current (I
KACh
) in inside-out patches. TP and ATR downregulated PKCα (by 33% and 37%, respectively) and caused membrane translocation of PKCε, switching PKC predominance to the stimulatory novel isoform. TP increased [Ca
2+
]
i
at 2 hours by 30%, with return to baseline at 24 hours. Buffering [Ca
2+
]
i
during TP with the cell-permeable Ca
2+
chelator BAPTA-AM (1 μmol/L) or inhibiting the Ca
2+
-dependent protease calpain with PD150606 (20 μmol/L) prevented PKCα downregulation and TP enhancement of I
KAChC
. PKCε inhibition with a cell-permeable peptide inhibitor suppressed TP/ATR-induced I
KAChC
activation, whereas cPKC inhibition enhanced I
KAChC
activity in 1-Hz cells.
Conclusions:
PKC isoforms differentially modulate I
KACh
, with conventional Ca
2+
-dependent isoforms inhibiting and novel isoforms enhancing activity. ATR causes a rate-dependent PKC isoform switch, with Ca
2+
/calpain-dependent downregulation of inhibitory PKCα and membrane translocation of stimulatory PKCε, enhancing I
KAChC
. These findings provide novel insights into mechanisms underlying I
KAChC
dysregulation in AF.
Collapse
Affiliation(s)
- Samy Makary
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Niels Voigt
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Ange Maguy
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Reza Wakili
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Kunihiro Nishida
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Masahide Harada
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Dobromir Dobrev
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Stanley Nattel
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| |
Collapse
|
12
|
Song CY, Xi HJ, Yang L, Qu LH, Zi-YongYue, Zhou J, Cui XG, Gao W, Wang N, Pan ZW, Li WZ. Propofol inhibited the delayed rectifier potassium current (Ik) via activation of protein kinase C epsilon in rat parietal cortical neurons. Eur J Pharmacol 2011; 653:16-20. [DOI: 10.1016/j.ejphar.2010.10.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 10/06/2010] [Accepted: 10/22/2010] [Indexed: 11/24/2022]
|
13
|
Ding WG, Toyoda F, Ueyama H, Matsuura H. Lysophosphatidylcholine enhances IKs currents in cardiac myocytes through activation of G protein, PKC and Rho signaling pathways. J Mol Cell Cardiol 2011; 50:58-65. [DOI: 10.1016/j.yjmcc.2010.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 10/04/2010] [Accepted: 10/05/2010] [Indexed: 12/15/2022]
|
14
|
Harmati G, Papp F, Szentandrássy N, Bárándi L, Ruzsnavszky F, Horváth B, Bányász T, Magyar J, Panyi G, Krasznai Z, Nánási PP. Effects of the PKC inhibitors chelerythrine and bisindolylmaleimide I (GF 109203X) on delayed rectifier K+ currents. Naunyn Schmiedebergs Arch Pharmacol 2010; 383:141-8. [PMID: 21120453 DOI: 10.1007/s00210-010-0584-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 11/19/2010] [Indexed: 11/30/2022]
Abstract
Protein kinase C (PKC) inhibitors are useful tools for studying PKC-dependent regulation of ion channels. For this purpose, high PKC specificity is a basic requirement excluding any direct interaction between the PKC inhibitor and the ion channel. In the present study, the effects of two frequently applied PKC inhibitors, chelerythine and bisindolylmaleimide I, were studied on the rapid and slow components of the delayed rectifier K(+) current (I(Kr) and I(Ks)) in canine ventricular cardiomyocytes and on the human ether-à-go-go-related gene (hERG) channels expressed in human embryonic kidney (HEK) cells. The whole cell version of the patch clamp technique was used in all experiments. Chelerythrine and bisindolylmaleimide I (both 1 μM) suppressed I(Kr) in canine ventricular cells. This inhibition developed rapidly, suggesting a direct drug-channel interaction. In HEK cells heterologously expressing hERG channels, chelerythrine and bisindolylmaleimide I blocked hERG current in a concentration-dependent manner, having EC(50) values of 0.11 ± 0.01 and 0.76 ± 0.04 μM, respectively. Both chelerythrine and bisindolylmaleimide I strongly modified gating kinetics of hERG--voltage dependence of activation was shifted towards more negative voltages and activation was accelerated. Deactivation was slowed by bisindolylmaleimide I but not by chelerythrine. I(Ks) was not significantly altered by bisindolylmaleimide I and chelerythrine. No significant effect of 0.1 μM bisindolylmaleimide I or 0.1 μM PMA (PKC activator) was observed on I(Kr) arguing against significant contribution of PKC to regulation of I(Kr). It is concluded that neither chelerythrine nor bisindolylmaleimide I is suitable for selective PKC blockade due to their direct blocking actions on the hERG channel.
Collapse
Affiliation(s)
- Gábor Harmati
- Department of Physiology, University of Debrecen, 4012, Debrecen, P.O. Box 22, Hungary
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Wang S, Xu DJ, Cai JB, Huang YZ, Zou JG, Cao KJ. Rapid component I(Kr) of cardiac delayed rectifier potassium currents in guinea-pig is inhibited by alpha(1)-adrenoreceptor activation via protein kinase A and protein kinase C-dependent pathways. Eur J Pharmacol 2009; 608:1-6. [PMID: 19233158 DOI: 10.1016/j.ejphar.2009.02.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 02/06/2009] [Accepted: 02/12/2009] [Indexed: 11/29/2022]
Abstract
Ventricular tachyarrhythmias are often precipitated by physical or emotional stress, indicating a link between increased adrenergic stimulation and cardiac ion channel activity. Human ether-a-go-go related gene (hERG) potassium channels conduct the rapid component of delayed rectifier potassium current, I(kr), a crucial component for action potential repolarization. To evaluate the correlation between increased alpha(1)-adrenergic activity and the rapid component of cardiac I(kr), whole-cell patch-clamp recording was performed in isolated guinea-pig ventricular myocytes. Stimulation of alpha(1)-adrenoceptors using phenylephrine (0.1 nM-100 microM) reduced I(kr) current in a dose-dependent manner at 37 degrees C. Phenylephrine (0.1 microM) reduced I(kr) current to 66.83+/-3.16%. Chelerythrine (1 microM), a specific inhibitor of protein kinase C (PKC) completely inhibited the changes in I(kr) trigged by 0.1 microM phenylephrine. KT5720 (2.5 microM), a specific inhibitor of protein kinase A (PKA) partially inhibited the current decrease induced by 0.1 microM phenylephrine. Both chelerythrine and KT5720 drastically reduced the phenylephrine-induced effects, indicating possible involvement of PKC and PKA in the alpha(1)-adrenergic inhibition of I(kr). Our data suggest a link between I(kr) and the alpha(1)-adrenoceptor, involving activation of PKC and PKA in arrhythmogenesis.
Collapse
Affiliation(s)
- Sen Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | | | | | | | | | | |
Collapse
|
16
|
Srivastava AK, Panda G. Total synthesis of (-)-balanol, all stereoisomers, their N-tosyl analogues, and fully protected ophiocordin: an easy route to hexahydroazepine cores from garner aldehydes. Chemistry 2008; 14:4675-88. [PMID: 18399526 DOI: 10.1002/chem.200701991] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Total syntheses of (-)-balanol and all of its stereoisomers starting from easily available Garner aldehydes are described. Diastereoselective Grignard reactions on Garner aldehydes and ring-closing metatheses are the key steps for the construction of hexahydroazepine subunits. The benzophenone subunits were constructed through coupling of suitably functionalized aromatic aldehyde and bromo components. The synthetic route constitutes a convenient and scalable reaction sequence to generate all of the stereoisomers of balanol. The methodology is explored further for the synthesis of N-tosyl analogues of balanol and of fully protected ophiocordin.
Collapse
Affiliation(s)
- Ajay Kumar Srivastava
- Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, UP, India
| | | |
Collapse
|