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Zheng M, Erhardt S, Cao Y, Wang J. Emerging Signaling Regulation of Sinoatrial Node Dysfunction. Curr Cardiol Rep 2023; 25:621-630. [PMID: 37227579 DOI: 10.1007/s11886-023-01885-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/14/2023] [Indexed: 05/26/2023]
Abstract
PURPOSE OF REVIEW The sinoatrial node (SAN), the natural pacemaker of the heart, is responsible for generating electrical impulses and initiating each heartbeat. Sinoatrial node dysfunction (SND) causes various arrhythmias such as sinus arrest, SAN block, and tachycardia/bradycardia syndrome. Unraveling the underlying mechanisms of SND is of paramount importance in the pursuit of developing effective therapeutic strategies for patients with SND. This review provides a concise summary of the most recent progress in the signaling regulation of SND. RECENT FINDINGS Recent studies indicate that SND can be caused by abnormal intercellular and intracellular signaling, various forms of heart failure (HF), and diabetes. These discoveries provide novel insights into the underlying mechanisms SND, advancing our understanding of its pathogenesis. SND can cause severe cardiac arrhythmias associated with syncope and an increased risk of sudden death. In addition to ion channels, the SAN is susceptible to the influence of various signalings including Hippo, AMP-activated protein kinase (AMPK), mechanical force, and natriuretic peptide receptors. New cellular and molecular mechanisms related to SND are also deciphered in systemic diseases such as HF and diabetes. Progress in these studies contributes to the development of potential therapeutics for SND.
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Affiliation(s)
- Mingjie Zheng
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Shannon Erhardt
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, 77030, USA
| | - Yuhan Cao
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Jun Wang
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, 77030, USA.
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Herrera-Pérez S, Lamas JA. TREK channels in Mechanotransduction: a Focus on the Cardiovascular System. Front Cardiovasc Med 2023; 10:1180242. [PMID: 37288256 PMCID: PMC10242076 DOI: 10.3389/fcvm.2023.1180242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/26/2023] [Indexed: 06/09/2023] Open
Abstract
Mechano-electric feedback is one of the most important subsystems operating in the cardiovascular system, but the underlying molecular mechanism remains rather unknown. Several proteins have been proposed to explain the molecular mechanism of mechano-transduction. Transient receptor potential (TRP) and Piezo channels appear to be the most important candidates to constitute the molecular mechanism behind of the inward current in response to a mechanical stimulus. However, the inhibitory/regulatory processes involving potassium channels that operate on the cardiac system are less well known. TWIK-Related potassium (TREK) channels have emerged as strong candidates due to their capacity for the regulation of the flow of potassium in response to mechanical stimuli. Current data strongly suggest that TREK channels play a role as mechano-transducers in different components of the cardiovascular system, not only at central (heart) but also at peripheral (vascular) level. In this context, this review summarizes and highlights the main existing evidence connecting this important subfamily of potassium channels with the cardiac mechano-transduction process, discussing molecular and biophysical aspects of such a connection.
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Affiliation(s)
- Salvador Herrera-Pérez
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - José Antonio Lamas
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
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Baldwin TA, Li Y, Marsden AN, Rinné S, Garza‐Carbajal A, Schindler RFR, Zhang M, Garcia MA, Venna VR, Decher N, Brand T, Dessauer CW. POPDC1 scaffolds a complex of adenylyl cyclase 9 and the potassium channel TREK-1 in heart. EMBO Rep 2022; 23:e55208. [PMID: 36254885 PMCID: PMC9724675 DOI: 10.15252/embr.202255208] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022] Open
Abstract
The establishment of macromolecular complexes by scaffolding proteins is key to the local production of cAMP by anchored adenylyl cyclase (AC) and the subsequent cAMP signaling necessary for cardiac functions. We identify a novel AC scaffold, the Popeye domain-containing (POPDC) protein. The POPDC family of proteins is important for cardiac pacemaking and conduction, due in part to their cAMP-dependent binding and regulation of TREK-1 potassium channels. We show that TREK-1 binds the AC9:POPDC1 complex and copurifies in a POPDC1-dependent manner with AC9 activity in heart. Although the AC9:POPDC1 interaction is cAMP-independent, TREK-1 association with AC9 and POPDC1 is reduced upon stimulation of the β-adrenergic receptor (βAR). AC9 activity is required for βAR reduction of TREK-1 complex formation with AC9:POPDC1 and in reversing POPDC1 enhancement of TREK-1 currents. Finally, deletion of the gene-encoding AC9 (Adcy9) gives rise to bradycardia at rest and stress-induced heart rate variability, a milder phenotype than the loss of Popdc1 but similar to the loss of Kcnk2 (TREK-1). Thus, POPDC1 represents a novel adaptor for AC9 interactions with TREK-1 to regulate heart rate control.
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Affiliation(s)
- Tanya A Baldwin
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Yong Li
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Autumn N Marsden
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior MCMBBPhilipps‐University of MarburgMarburgGermany
| | - Anibal Garza‐Carbajal
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | | | - Musi Zhang
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Mia A Garcia
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Venugopal Reddy Venna
- Department NeurologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior MCMBBPhilipps‐University of MarburgMarburgGermany
| | - Thomas Brand
- National Heart and Lung Institute, Imperial College LondonLondonUK
| | - Carmen W Dessauer
- Department Integrative Biology and PharmacologyMcGovern Medical School, University of Texas Health Science CenterHoustonTXUSA
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Herrera-Pérez S, Rueda-Ruzafa L, Campos-Ríos A, Fernández-Fernández D, Lamas J. Antiarrhythmic calcium channel blocker verapamil inhibits trek currents in sympathetic neurons. Front Pharmacol 2022; 13:997188. [PMID: 36188584 PMCID: PMC9522527 DOI: 10.3389/fphar.2022.997188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
Background and Purpose: Verapamil, a drug widely used in certain cardiac pathologies, exert its therapeutic effect mainly through the blockade of cardiac L-type calcium channels. However, we also know that both voltage-dependent and certain potassium channels are blocked by verapamil. Because sympathetic neurons of the superior cervical ganglion (SCG) are known to express a good variety of potassium currents, and to finely tune cardiac activity, we speculated that the effect of verapamil on these SCG potassium channels could explain part of the therapeutic action of this drug. To address this question, we decided to study, the effects of verapamil on three different potassium currents observed in SCG neurons: delayed rectifier, A-type and TREK (a subfamily of K2P channels) currents. We also investigated the effect of verapamil on the electrical behavior of sympathetic SCG neurons. Experimental Approach: We employed the Patch-Clamp technique to mouse SCG neurons in culture. Key Results: We found that verapamil depolarizes of the resting membrane potential of SCG neurons. Moreover, we demonstrated that this drug also inhibits A-type potassium currents. Finally, and most importantly, we revealed that the current driven through TREK channels is also inhibited in the presence of verapamil. Conclusion and Implications: We have shown that verapamil causes a clear alteration of excitability in sympathetic nerve cells. This fact undoubtedly leads to an alteration of the sympathetic-parasympathetic balance which may affect cardiac function. Therefore, we propose that these possible peripheral alterations in the autonomic system should be taken into consideration in the prescription of this drug.
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Affiliation(s)
- S. Herrera-Pérez
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Grupo de Neurofisiología Experimental y Circuitos Neuronales, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
- *Correspondence: S. Herrera-Pérez, ; J. A. Lamas,
| | - L. Rueda-Ruzafa
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - A. Campos-Ríos
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | | | - J.A. Lamas
- Laboratory of Neuroscience, CINBIO, University of Vigo, Vigo, Spain
- Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
- *Correspondence: S. Herrera-Pérez, ; J. A. Lamas,
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Tibbo AJ, Mika D, Dobi S, Ling J, McFall A, Tejeda GS, Blair C, MacLeod R, MacQuaide N, Gök C, Fuller W, Smith BO, Smith GL, Vandecasteele G, Brand T, Baillie GS. Phosphodiesterase type 4 anchoring regulates cAMP signaling to Popeye domain-containing proteins. J Mol Cell Cardiol 2022; 165:86-102. [PMID: 34999055 PMCID: PMC8986152 DOI: 10.1016/j.yjmcc.2022.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/16/2021] [Accepted: 01/03/2022] [Indexed: 12/04/2022]
Abstract
Cyclic AMP is a ubiquitous second messenger used to transduce intracellular signals from a variety of Gs-coupled receptors. Compartmentalisation of protein intermediates within the cAMP signaling pathway underpins receptor-specific responses. The cAMP effector proteins protein-kinase A and EPAC are found in complexes that also contain phosphodiesterases whose presence ensures a coordinated cellular response to receptor activation events. Popeye domain containing (POPDC) proteins are the most recent class of cAMP effectors to be identified and have crucial roles in cardiac pacemaking and conduction. We report the first observation that POPDC proteins exist in complexes with members of the PDE4 family in cardiac myocytes. We show that POPDC1 preferentially binds the PDE4A sub-family via a specificity motif in the PDE4 UCR1 region and that PDE4s bind to the Popeye domain of POPDC1 in a region known to be susceptible to a mutation that causes human disease. Using a cell-permeable disruptor peptide that displaces the POPDC1-PDE4 complex we show that PDE4 activity localized to POPDC1 modulates cycle length of spontaneous Ca2+ transients firing in intact mouse sinoatrial nodes. POPDC1 forms a complex with type 4 phosphodiesterases (PDE4s) in cardiac myocytes. POPDC1 binds PDE4 enzymes in the Upstream Conserved Region 1 (UCR1) domain. The PDE4 binding motif within the Popeye domain lies in a region that harbours a mutation, which underpins human disease. Disruption of the POPDC1-PDE4 complex modulates the cycle length of spontaneous Ca2+ transients in the sinoatrial node. Disruption of the POPDC1-PDE4 complex causes a significant prolongation of the action potential repolarization phase.
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Affiliation(s)
- Amy J Tibbo
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Delphine Mika
- Université Paris-Saclay, Inserm, Signaling and Cardiovascular Pathophysiology, UMR-S 1180, 92296 Châtenay-Malabry, France
| | - Sara Dobi
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Jiayue Ling
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Aisling McFall
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Gonzalo S Tejeda
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Connor Blair
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Ruth MacLeod
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Niall MacQuaide
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Caglar Gök
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - William Fuller
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Brian O Smith
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Godfrey L Smith
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Grégoire Vandecasteele
- Université Paris-Saclay, Inserm, Signaling and Cardiovascular Pathophysiology, UMR-S 1180, 92296 Châtenay-Malabry, France
| | - Thomas Brand
- National Heart and Lung Institute, Imperial College, W12 0NN, London
| | - George S Baillie
- College of Veterinary, Medical and Life Sciences, University of Glasgow, Glasgow G128QQ, UK.
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Gruscheski L, Brand T. The Role of POPDC Proteins in Cardiac Pacemaking and Conduction. J Cardiovasc Dev Dis 2021; 8:160. [PMID: 34940515 PMCID: PMC8706714 DOI: 10.3390/jcdd8120160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 11/17/2022] Open
Abstract
The Popeye domain-containing (POPDC) gene family, consisting of Popdc1 (also known as Bves), Popdc2, and Popdc3, encodes transmembrane proteins abundantly expressed in striated muscle. POPDC proteins have recently been identified as cAMP effector proteins and have been proposed to be part of the protein network involved in cAMP signaling. However, their exact biochemical activity is presently poorly understood. Loss-of-function mutations in animal models causes abnormalities in skeletal muscle regeneration, conduction, and heart rate adaptation after stress. Likewise, patients carrying missense or nonsense mutations in POPDC genes have been associated with cardiac arrhythmias and limb-girdle muscular dystrophy. In this review, we introduce the POPDC protein family, and describe their structure function, and role in cAMP signaling. Furthermore, the pathological phenotypes observed in zebrafish and mouse models and the clinical and molecular pathologies in patients carrying POPDC mutations are described.
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Affiliation(s)
| | - Thomas Brand
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK;
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7
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Huckstepp RTR, Funk GD. Release your inhibitions: The role of post-inhibitory rebound and synaptic inhibition in the generation of expiratory activity. J Physiol 2021; 599:5331-5332. [PMID: 34783025 DOI: 10.1113/jp282482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 11/10/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
| | - Gregory D Funk
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
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8
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Two-Pore-Domain Potassium (K 2P-) Channels: Cardiac Expression Patterns and Disease-Specific Remodelling Processes. Cells 2021; 10:cells10112914. [PMID: 34831137 PMCID: PMC8616229 DOI: 10.3390/cells10112914] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/23/2022] Open
Abstract
Two-pore-domain potassium (K2P-) channels conduct outward K+ currents that maintain the resting membrane potential and modulate action potential repolarization. Members of the K2P channel family are widely expressed among different human cell types and organs where they were shown to regulate important physiological processes. Their functional activity is controlled by a broad variety of different stimuli, like pH level, temperature, and mechanical stress but also by the presence of lipids or pharmacological agents. In patients suffering from cardiovascular diseases, alterations in K2P-channel expression and function have been observed, suggesting functional significance and a potential therapeutic role of these ion channels. For example, upregulation of atrial specific K2P3.1 (TASK-1) currents in atrial fibrillation (AF) patients was shown to contribute to atrial action potential duration shortening, a key feature of AF-associated atrial electrical remodelling. Therefore, targeting K2P3.1 (TASK-1) channels might constitute an intriguing strategy for AF treatment. Further, mechanoactive K2P2.1 (TREK-1) currents have been implicated in the development of cardiac hypertrophy, cardiac fibrosis and heart failure. Cardiovascular expression of other K2P channels has been described, functional evidence in cardiac tissue however remains sparse. In the present review, expression, function, and regulation of cardiovascular K2P channels are summarized and compared among different species. Remodelling patterns, observed in disease models are discussed and compared to findings from clinical patients to assess the therapeutic potential of K2P channels.
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Turner D, Kang C, Mesirca P, Hong J, Mangoni ME, Glukhov AV, Sah R. Electrophysiological and Molecular Mechanisms of Sinoatrial Node Mechanosensitivity. Front Cardiovasc Med 2021; 8:662410. [PMID: 34434970 PMCID: PMC8382116 DOI: 10.3389/fcvm.2021.662410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023] Open
Abstract
The understanding of the electrophysiological mechanisms that underlie mechanosensitivity of the sinoatrial node (SAN), the primary pacemaker of the heart, has been evolving over the past century. The heart is constantly exposed to a dynamic mechanical environment; as such, the SAN has numerous canonical and emerging mechanosensitive ion channels and signaling pathways that govern its ability to respond to both fast (within second or on beat-to-beat manner) and slow (minutes) timescales. This review summarizes the effects of mechanical loading on the SAN activity and reviews putative candidates, including fast mechanoactivated channels (Piezo, TREK, and BK) and slow mechanoresponsive ion channels [including volume-regulated chloride channels and transient receptor potential (TRP)], as well as the components of mechanochemical signal transduction, which may contribute to SAN mechanosensitivity. Furthermore, we examine the structural foundation for both mechano-electrical and mechanochemical signal transduction and discuss the role of specialized membrane nanodomains, namely, caveolae, in mechanical regulation of both membrane and calcium clock components of the so-called coupled-clock pacemaker system responsible for SAN automaticity. Finally, we emphasize how these mechanically activated changes contribute to the pathophysiology of SAN dysfunction and discuss controversial areas necessitating future investigations. Though the exact mechanisms of SAN mechanosensitivity are currently unknown, identification of such components, their impact into SAN pacemaking, and pathological remodeling may provide new therapeutic targets for the treatment of SAN dysfunction and associated rhythm abnormalities.
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Affiliation(s)
- Daniel Turner
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
| | - Chen Kang
- Cardiovascular Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Juan Hong
- Cardiovascular Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
| | - Rajan Sah
- Cardiovascular Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States
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Wang Y, Fu Z, Ma Z, Li N, Shang H. Bepridil, a class IV antiarrhythmic agent, can block the TREK-1 potassium channel. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1123. [PMID: 34430564 PMCID: PMC8350656 DOI: 10.21037/atm-20-7971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/17/2021] [Indexed: 11/24/2022]
Abstract
Background The TWIK-related potassium channel (TREK-1) can be regulated by different stimuli. However, it is not clear whether some antiarrhythmics affect the activity of TREK-1. In the present study, the effect of bepridil on the TREK-1 currents is investigated. Methods In a TREK-1 stably-expressed HEK-293 cell line (HEK-TREK-1), U251MG cells, and isolated mouse ventricular myocytes, the TREK-1 current and action potentials were recorded by the patch-clamp technique. The standard voltage protocol was a 200 ms constant potential at 20 mV, followed bya 500 ms ramp from –90 to +20 mV (HEK-TREK-1) or +80 mV (U251MG cells and myocytes) every 10 s. The currents at +20 mV or +80 mV were used for analysis. The docking study of bepridil’s binding model in the TREK-1 channel was performed using the Swissdock web service. Results In HEK-TREK-1 cells, BL1249 induced a significantly large outwardly rectifying current with similar baseline TREK-1 current characteristic, with a reversal potential (−70 mV). The concentration of half-maximal activation (EC50) of BL1249 was 3.45 µM. However, bepridil decreased the baseline TREK-1 currents, with a concentration of half-maximal inhibition (IC50) 0.59 µM and a Hill coefficient of 1.1. Also, bepridil inhibited BL1249-activated TREK-1 currents, with an IC50 4.08 µM and a Hill coefficient of 3.22. The outside-out patch-clamp confirmed bepridil inhibited BL1249-activated TREK-1 currents. In U251MG cells and myocytes, BL1249 activated outwardly rectifying endogenous TREK-1 currents, which could be inhibited by bepridil. BL1249 (10 µM) could decrease the peak value and reduce the duration of the action potential. Bepridil (10 µM) prolonged the duration of action potential of myocytes. The docking study revealed that bepridil might affect the K+ pore domain and the M4 modulator pocket. Conclusions Bepridil may be a blocker for the TREK-1K+channel at a clinically therapeutic concentration, providing a new mechanism of TREK-1 regulation and bepridil's antiarrhythmic effect.
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Affiliation(s)
- Ying Wang
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Department of Cardiology, Qilu Hospital, Shandong University, Jinan, China
| | - Zhijie Fu
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Department of Cardiology, Qilu Hospital, Shandong University, Jinan, China.,Department of Otorhinolaryngology, the First Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Zhiyong Ma
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Department of Cardiology, Qilu Hospital, Shandong University, Jinan, China
| | - Na Li
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Department of Cardiology, Qilu Hospital, Shandong University, Jinan, China
| | - Hong Shang
- Key Laboratory of Cardiovascular Proteomics of Shandong Province, Department of Geriatrics, Qilu Hospital, Shandong University, Jinan, China
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11
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Lengyel M, Enyedi P, Czirják G. Negative Influence by the Force: Mechanically Induced Hyperpolarization via K 2P Background Potassium Channels. Int J Mol Sci 2021; 22:ijms22169062. [PMID: 34445768 PMCID: PMC8396510 DOI: 10.3390/ijms22169062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
The two-pore domain K2P subunits form background (leak) potassium channels, which are characterized by constitutive, although not necessarily constant activity, at all membrane potential values. Among the fifteen pore-forming K2P subunits encoded by the KCNK genes, the three members of the TREK subfamily, TREK-1, TREK-2, and TRAAK are mechanosensitive ion channels. Mechanically induced opening of these channels generally results in outward K+ current under physiological conditions, with consequent hyperpolarization and inhibition of membrane potential-dependent cellular functions. In the past decade, great advances have been made in the investigation of the molecular determinants of mechanosensation, and members of the TREK subfamily have emerged among the best-understood examples of mammalian ion channels directly influenced by the tension of the phospholipid bilayer. In parallel, the crucial contribution of mechano-gated TREK channels to the regulation of membrane potential in several cell types has been reported. In this review, we summarize the general principles underlying the mechanical activation of K2P channels, and focus on the physiological roles of mechanically induced hyperpolarization.
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12
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Herrera-Pérez S, Campos-Ríos A, Rueda-Ruzafa L, Lamas JA. Contribution of K2P Potassium Channels to Cardiac Physiology and Pathophysiology. Int J Mol Sci 2021; 22:ijms22126635. [PMID: 34205717 PMCID: PMC8234311 DOI: 10.3390/ijms22126635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/08/2021] [Accepted: 06/18/2021] [Indexed: 12/28/2022] Open
Abstract
Years before the first two-pore domain potassium channel (K2P) was cloned, certain ion channels had already been demonstrated to be present in the heart with characteristics and properties usually attributed to the TREK channels (a subfamily of K2P channels). K2P channels were later detected in cardiac tissue by RT-PCR, although the distribution of the different K2P subfamilies in the heart seems to depend on the species analyzed. In order to collect relevant information in this regard, we focus here on the TWIK, TASK and TREK cardiac channels, their putative roles in cardiac physiology and their implication in coronary pathologies. Most of the RNA expression data and electrophysiological recordings available to date support the presence of these different K2P subfamilies in distinct cardiac cells. Likewise, we show how these channels may be involved in certain pathologies, such as atrial fibrillation, long QT syndrome and Brugada syndrome.
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13
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Regulation of Cardiac Conduction and Arrhythmias by Ankyrin/Spectrin-Based Macromolecular Complexes. J Cardiovasc Dev Dis 2021; 8:jcdd8050048. [PMID: 33946725 PMCID: PMC8146975 DOI: 10.3390/jcdd8050048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The cardiac conduction system is an extended network of excitable tissue tasked with generation and propagation of electrical impulses to signal coordinated contraction of the heart. The fidelity of this system depends on the proper spatio-temporal regulation of ion channels in myocytes throughout the conduction system. Importantly, inherited or acquired defects in a wide class of ion channels has been linked to dysfunction at various stages of the conduction system resulting in life-threatening cardiac arrhythmia. There is growing appreciation of the role that adapter and cytoskeletal proteins play in organizing ion channel macromolecular complexes critical for proper function of the cardiac conduction system. In particular, members of the ankyrin and spectrin families have emerged as important nodes for normal expression and regulation of ion channels in myocytes throughout the conduction system. Human variants impacting ankyrin/spectrin function give rise to a broad constellation of cardiac arrhythmias. Furthermore, chronic neurohumoral and biomechanical stress promotes ankyrin/spectrin loss of function that likely contributes to conduction disturbances in the setting of acquired cardiac disease. Collectively, this review seeks to bring attention to the significance of these cytoskeletal players and emphasize the potential therapeutic role they represent in a myriad of cardiac disease states.
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14
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Stewart L, Turner NA. Channelling the Force to Reprogram the Matrix: Mechanosensitive Ion Channels in Cardiac Fibroblasts. Cells 2021; 10:990. [PMID: 33922466 PMCID: PMC8145896 DOI: 10.3390/cells10050990] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/13/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac fibroblasts (CF) play a pivotal role in preserving myocardial function and integrity of the heart tissue after injury, but also contribute to future susceptibility to heart failure. CF sense changes to the cardiac environment through chemical and mechanical cues that trigger changes in cellular function. In recent years, mechanosensitive ion channels have been implicated as key modulators of a range of CF functions that are important to fibrotic cardiac remodelling, including cell proliferation, myofibroblast differentiation, extracellular matrix turnover and paracrine signalling. To date, seven mechanosensitive ion channels are known to be functional in CF: the cation non-selective channels TRPC6, TRPM7, TRPV1, TRPV4 and Piezo1, and the potassium-selective channels TREK-1 and KATP. This review will outline current knowledge of these mechanosensitive ion channels in CF, discuss evidence of the mechanosensitivity of each channel, and detail the role that each channel plays in cardiac remodelling. By better understanding the role of mechanosensitive ion channels in CF, it is hoped that therapies may be developed for reducing pathological cardiac remodelling.
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Affiliation(s)
| | - Neil A. Turner
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds LS2 9JT, UK;
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15
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Wallace MJ, El Refaey M, Mesirca P, Hund TJ, Mangoni ME, Mohler PJ. Genetic Complexity of Sinoatrial Node Dysfunction. Front Genet 2021; 12:654925. [PMID: 33868385 PMCID: PMC8047474 DOI: 10.3389/fgene.2021.654925] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/01/2021] [Indexed: 12/13/2022] Open
Abstract
The pacemaker cells of the cardiac sinoatrial node (SAN) are essential for normal cardiac automaticity. Dysfunction in cardiac pacemaking results in human sinoatrial node dysfunction (SND). SND more generally occurs in the elderly population and is associated with impaired pacemaker function causing abnormal heart rhythm. Individuals with SND have a variety of symptoms including sinus bradycardia, sinus arrest, SAN block, bradycardia/tachycardia syndrome, and syncope. Importantly, individuals with SND report chronotropic incompetence in response to stress and/or exercise. SND may be genetic or secondary to systemic or cardiovascular conditions. Current management of patients with SND is limited to the relief of arrhythmia symptoms and pacemaker implantation if indicated. Lack of effective therapeutic measures that target the underlying causes of SND renders management of these patients challenging due to its progressive nature and has highlighted a critical need to improve our understanding of its underlying mechanistic basis of SND. This review focuses on current information on the genetics underlying SND, followed by future implications of this knowledge in the management of individuals with SND.
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Affiliation(s)
- Michael J. Wallace
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Mona El Refaey
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Pietro Mesirca
- CNRS, INSERM, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France
- Laboratory of Excellence ICST, Montpellier, France
| | - Thomas J. Hund
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - Matteo E. Mangoni
- CNRS, INSERM, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France
- Laboratory of Excellence ICST, Montpellier, France
| | - Peter J. Mohler
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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16
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Mesirca P, Fedorov VV, Hund TJ, Torrente AG, Bidaud I, Mohler PJ, Mangoni ME. Pharmacologic Approach to Sinoatrial Node Dysfunction. Annu Rev Pharmacol Toxicol 2020; 61:757-778. [PMID: 33017571 DOI: 10.1146/annurev-pharmtox-031120-115815] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The spontaneous activity of the sinoatrial node initiates the heartbeat. Sino-atrial node dysfunction (SND) and sick sinoatrial (sick sinus) syndrome are caused by the heart's inability to generate a normal sinoatrial node action potential. In clinical practice, SND is generally considered an age-related pathology, secondary to degenerative fibrosis of the heart pacemaker tissue. However, other forms of SND exist, including idiopathic primary SND, which is genetic, and forms that are secondary to cardiovascular or systemic disease. The incidence of SND in the general population is expected to increase over the next half century, boosting the need to implant electronic pacemakers. During the last two decades, our knowledge of sino-atrial node physiology and of the pathophysiological mechanisms underlying SND has advanced considerably. This review summarizes the current knowledge about SND mechanisms and discusses the possibility of introducing new pharmacologic therapies for treating SND.
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Affiliation(s)
- Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Vadim V Fedorov
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Thomas J Hund
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Angelo G Torrente
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Peter J Mohler
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA.,Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
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17
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POPDC2 a novel susceptibility gene for conduction disorders. J Mol Cell Cardiol 2020; 145:74-83. [PMID: 32535041 DOI: 10.1016/j.yjmcc.2020.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/22/2020] [Accepted: 06/09/2020] [Indexed: 01/25/2023]
Abstract
Despite recent progress in the understanding of cardiac ion channel function and its role in inherited forms of ventricular arrhythmias, the molecular basis of cardiac conduction disorders often remains unresolved. We aimed to elucidate the genetic background of familial atrioventricular block (AVB) using a whole exome sequencing (WES) approach. In monozygotic twins with a third-degree AVB and in another, unrelated family with first-degree AVB, we identified a heterozygous nonsense mutation in the POPDC2 gene causing a premature stop at position 188 (POPDC2W188⁎), deleting parts of its cAMP binding-domain. Popeye-domain containing (POPDC) proteins are predominantly expressed in the skeletal muscle and the heart, with particularly high expression of POPDC2 in the sinoatrial node of the mouse. We now show by quantitative PCR experiments that in the human heart the POPDC-modulated two-pore domain potassium (K2P) channel TREK-1 is preferentially expressed in the atrioventricular node. Co-expression studies in Xenopus oocytes revealed that POPDC2W188⁎ causes a loss-of-function with impaired TREK-1 modulation. Consistent with the high expression level of POPDC2 in the murine sinoatrial node, POPDC2W188⁎ knock-in mice displayed stress-induced sinus bradycardia and pauses, a phenotype that was previously also reported for POPDC2 and TREK-1 knock-out mice. We propose that the POPDC2W188⁎ loss-of-function mutation contributes to AVB pathogenesis by an aberrant modulation of TREK-1, highlighting that POPDC2 represents a novel arrhythmia gene for cardiac conduction disorders.
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18
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Arazi E, Blecher G, Zilberberg N. A regulatory domain in the K 2P2.1 (TREK-1) carboxyl-terminal allows for channel activation by monoterpenes. Mol Cell Neurosci 2020; 105:103496. [PMID: 32320829 DOI: 10.1016/j.mcn.2020.103496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 04/12/2020] [Accepted: 04/15/2020] [Indexed: 11/30/2022] Open
Abstract
Potassium K2P ('leak') channels conduct current across the entire physiological voltage range and carry leak or 'background' currents that are, in part, time- and voltage-independent. K2P2.1 channels (i.e., TREK-1, KCNK2) are highly expressed in excitable tissues, where they play a key role in the cellular mechanisms of neuroprotection, anesthesia, pain perception, and depression. Here, we report for the first time that human K2P2.1 channel activity is regulated by monoterpenes (MTs). We found that cyclic, aromatic monoterpenes containing a phenol moiety, such as carvacrol, thymol and 4-IPP had the most profound effect on current flowing through the channel (up to a 6-fold increase). By performing sequential truncation of the carboxyl-terminal domain of the channel and testing the activity of several channel regulators, we identified two distinct regulatory domains within this portion of the protein. One domain, as previously reported, was needed for regulation by arachidonic acid, anionic phospholipids, and temperature changes. Within a second domain, a triple arginine residue motif (R344-346), an apparent PIP2-binding site, was found to be essential for regulation by holding potential changes and important for regulation by monoterpenes.
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Affiliation(s)
- Eden Arazi
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Galit Blecher
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Noam Zilberberg
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel; Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel.
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19
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Wang W, Kiyoshi CM, Du Y, Taylor AT, Sheehan ER, Wu X, Zhou M. TREK-1 Null Impairs Neuronal Excitability, Synaptic Plasticity, and Cognitive Function. Mol Neurobiol 2020; 57:1332-1346. [PMID: 31728930 PMCID: PMC8808335 DOI: 10.1007/s12035-019-01828-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023]
Abstract
TREK-1, a two-pore-domain K+ channel, is highly expressed in the central nervous system. Although aberrant expression of TREK-1 is implicated in cognitive impairment, the cellular and functional mechanism underlying this channelopathy is poorly understood. Here we examined TREK-1 contribution to neuronal morphology, excitability, synaptic plasticity, and cognitive function in mice deficient in TREK-1 expression. TREK-1 immunostaining signal mainly appeared in hippocampal pyramidal neurons, but not in astrocytes. TREK-1 gene knockout (TREK-1 KO) increases dendritic sprouting and the number of immature spines in hippocampal CA1 pyramidal neurons. Functionally, TREK-1 KO increases neuronal excitability and enhances excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs). The increased EPSCs appear to be attributed to an increased release probability of presynaptic glutamate and functional expression of postsynaptic AMPA receptors. TREK-1 KO decreased the paired-pulse ratio and severely occluded the long-term potentiation (LTP) in the CA1 region. These altered synaptic transmission and plasticity are associated with recognition memory deficit in TREK-1 KO mice. Although astrocytic expression of TREK-1 has been reported in previous studies, TREK-1 KO does not alter astrocyte membrane K+ conductance or the syncytial network function in terms of syncytial isopotentiality. Altogether, TREK-1 KO profoundly affects the cellular structure and function of hippocampal pyramidal neurons. Thus, the impaired cognitive function in diseases associated with aberrant expression of TREK-1 should be attributed to the failure of this K+ channel in regulating neuronal morphology, excitability, synaptic transmission, and plasticity.
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Affiliation(s)
- Wei Wang
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
- Department of Physiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Conrad M Kiyoshi
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Anne T Taylor
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Erica R Sheehan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Xiao Wu
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
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20
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Kamatham S, Waters CM, Schwingshackl A, Mancarella S. TREK-1 protects the heart against ischemia-reperfusion-induced injury and from adverse remodeling after myocardial infarction. Pflugers Arch 2019; 471:1263-1272. [PMID: 31511966 DOI: 10.1007/s00424-019-02306-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 08/12/2019] [Accepted: 08/22/2019] [Indexed: 11/28/2022]
Abstract
The TWIK-related K+ channel (TREK-1) is a two-pore-domain potassium channel that produces background leaky potassium currents. TREK-1 has a protective role against ischemia-induced neuronal damage. TREK-1 is also expressed in the heart, but its role in myocardial ischemia-reperfusion (IR)-induced injury has not been examined. In the current study, we used a TREK-1 knockout (KO) mouse model to show that TREK-1 has a critical role in the cardiac I/R-induced injury and during remodeling after myocardial infarction (MI). At baseline, TREK-1 KO mice had similar blood pressure and heart rate as the wild-type (WT) mice. However, the lack of TREK-1 was associated with increased susceptibility to ischemic injury and compromised functional recovery following ex vivo I/R-induced injury. TREK-1 deficiency increased infarct size following permanent coronary artery ligation, resulting in greater systolic dysfunction than the WT counterpart. Electrocardiographic (ECG) analysis revealed QT interval prolongation in TREK-1 KO mice, but normal heart rate (HR). Acutely isolated TREK-1 KO cardiomyocytes exhibited prolonged Ca2+ transient duration associated with action potential duration (APD) prolongation. Our data suggest that TREK-1 has a protective effect against I/R-induced injury and influences the post-MI remodeling processes by regulating membrane potential and maintaining intracellular Ca2+ homeostasis. These data suggest that TREK-1 activation could be an effective strategy to provide cardioprotection against ischemia-induced damage.
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Affiliation(s)
- Samuel Kamatham
- Department of Physiology, University of Tennessee Health Sciences Center, 71 S. Manassas Street, Memphis, TN, 38163, USA
| | - Christopher M Waters
- Department of Physiology, Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA
| | - Andreas Schwingshackl
- Department of Pediatrics, University of California Los Angeles, Los Angeles, CA, USA
| | - Salvatore Mancarella
- Department of Physiology, University of Tennessee Health Sciences Center, 71 S. Manassas Street, Memphis, TN, 38163, USA.
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21
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Yang JH, Siregar AS, Kim EJ, Nyiramana MM, Shin EJ, Han J, Sohn JT, Kim JW, Kang D. Involvement of TREK-1 Channel in Cell Viability of H9c2 Rat Cardiomyoblasts Affected by Bupivacaine and Lipid Emulsion. Cells 2019; 8:cells8050454. [PMID: 31091801 PMCID: PMC6563050 DOI: 10.3390/cells8050454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 12/24/2022] Open
Abstract
Lipid emulsion (LE) therapy has been used to reduce overdose of bupivacaine (BPV)-induced cardiotoxicity. The TWIK-related potassium channel-1 (TREK-1) is inhibited by BPV and activated by polyunsaturated fatty acids, which are the main component in LE. These pharmacological properties inspired us to investigate whether the TREK-1 channel is associated with cell viability of H9c2 cardiomyoblasts affected by BPV and LE. Consistent with previous studies, BPV-induced cell death was reduced by LE treatment. The reduction in the TREK-1 expression level by BPV was alleviated by LE. The BPV cytotoxicity highly decreased in TREK-1 overexpressed cells but was the opposite in TREK-1 knocked-down cells. TREK-1 channel activators and inhibitors increased and decreased cell viability, respectively. BPV-induced depolarization of the plasma and mitochondrial membrane potential and increase in intracellular Ca2+ level were blocked by LE treatment. BPV-induced depolarization of membrane potential was reduced in TREK-1 overexpressed cells, indicating that TREK-1 channels mediate setting the resting membrane potentials as a background K+ channel in H9c2 cells. These results show that TREK-1 activity is involved in the BPV cytotoxicity and the antagonistic effect of LE in H9c2 cells and suggest that TREK-1 could be a target for action of BPV and LE.
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Affiliation(s)
- Jun Ho Yang
- Departments of Medicine and Thoracic and Cardiovascular Surgery, College of Medicine, Gyeongsang National University, Jinju 52727, Korea.
- Gyeongsang National University Changwon Hospital, Changwon 51472, Korea.
| | - Adrian S Siregar
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea.
| | - Eun-Jin Kim
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Marie Merci Nyiramana
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea.
| | - Eui-Jung Shin
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea.
| | - Jaehee Han
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
| | - Ju-Tae Sohn
- Department of Anesthesiology and Pain Medicine, College of Medicine, Gyeongsang National University, Jinju 52727, Korea.
| | - Jong Woo Kim
- Departments of Medicine and Thoracic and Cardiovascular Surgery, College of Medicine, Gyeongsang National University, Jinju 52727, Korea.
- Gyeongsang National University Changwon Hospital, Changwon 51472, Korea.
| | - Dawon Kang
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 52727, Korea.
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea.
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22
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Djillani A, Mazella J, Heurteaux C, Borsotto M. Role of TREK-1 in Health and Disease, Focus on the Central Nervous System. Front Pharmacol 2019; 10:379. [PMID: 31031627 PMCID: PMC6470294 DOI: 10.3389/fphar.2019.00379] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/26/2019] [Indexed: 01/22/2023] Open
Abstract
TREK-1 is the most studied background K2P channel. Its main role is to control cell excitability and maintain the membrane potential below the threshold of depolarization. TREK-1 is multi-regulated by a variety of physical and chemical stimuli which makes it a very promising and challenging target in the treatment of several pathologies. It is mainly expressed in the brain but also in heart, smooth muscle cells, endocrine pancreas, and prostate. In the nervous system, TREK-1 is involved in many physiological and pathological processes such as depression, neuroprotection, pain, and anesthesia. These properties explain why many laboratories and pharmaceutical companies have been focusing their research on screening and developing highly efficient modulators of TREK-1 channels. In this review, we summarize the different roles of TREK-1 that have been investigated so far in attempt to characterize pharmacological tools and new molecules to modulate cellular functions controlled by TREK-1.
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Affiliation(s)
- Alaeddine Djillani
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Université Côte d'Azur, Valbonne, France
| | - Jean Mazella
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Université Côte d'Azur, Valbonne, France
| | - Catherine Heurteaux
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Université Côte d'Azur, Valbonne, France
| | - Marc Borsotto
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Université Côte d'Azur, Valbonne, France
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23
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Lang D, Glukhov AV. Functional Microdomains in Heart's Pacemaker: A Step Beyond Classical Electrophysiology and Remodeling. Front Physiol 2018; 9:1686. [PMID: 30538641 PMCID: PMC6277479 DOI: 10.3389/fphys.2018.01686] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Spontaneous beating of the sinoatrial node (SAN), the primary pacemaker of the heart, is initiated, sustained, and regulated by a complex system that integrates ion channels and transporters on the cell membrane surface (often referred to as "membrane clock") with subcellular calcium handling machinery (by parity of reasoning referred to as an intracellular "Ca2+ clock"). Stable, rhythmic beating of the SAN is ensured by a rigorous synchronization between these two clocks highlighted in the coupled-clock system concept of SAN timekeeping. The emerging results demonstrate that such synchronization of the complex pacemaking machinery at the cellular level depends on tightly regulated spatiotemporal signals which are restricted to precise sub-cellular microdomains and associated with discrete clusters of different ion channels, transporters, and regulatory receptors. It has recently become evident that within the microdomains, various proteins form an interacting network and work together as a part of a macromolecular signaling complex. These protein-protein interactions are tightly controlled and regulated by a variety of neurohormonal signaling pathways and the diversity of cellular responses achieved with a limited pool of second messengers is made possible through the organization of essential signal components in particular microdomains. In this review, we highlight the emerging understanding of the functionality of distinct subcellular microdomains in SAN myocytes and their functional role in the accumulation and neurohormonal regulation of proteins involved in cardiac pacemaking. We also demonstrate how changes in scaffolding proteins may lead to microdomain-targeted remodeling and regulation of pacemaker proteins contributing to SAN dysfunction.
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Affiliation(s)
- Di Lang
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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24
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Unudurthi SD, Nassal D, Greer-Short A, Patel N, Howard T, Xu X, Onal B, Satroplus T, Hong D, Lane C, Dalic A, Koenig SN, Lehnig AC, Baer LA, Musa H, Stanford KI, Smith S, Mohler PJ, Hund TJ. βIV-Spectrin regulates STAT3 targeting to tune cardiac response to pressure overload. J Clin Invest 2018; 128:5561-5572. [PMID: 30226828 DOI: 10.1172/jci99245] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 09/13/2018] [Indexed: 01/19/2023] Open
Abstract
Heart failure (HF) remains a major source of morbidity and mortality in the US. The multifunctional Ca2+/calmodulin-dependent kinase II (CaMKII) has emerged as a critical regulator of cardiac hypertrophy and failure, although the mechanisms remain unclear. Previous studies have established that the cytoskeletal protein βIV-spectrin coordinates local CaMKII signaling. Here, we sought to determine the role of a spectrin-CaMKII complex in maladaptive remodeling in HF. Chronic pressure overload (6 weeks of transaortic constriction [TAC]) induced a decrease in cardiac function in WT mice but not in animals expressing truncated βIV-spectrin lacking spectrin-CaMKII interaction (qv3J mice). Underlying the observed differences in function was an unexpected differential regulation of STAT3-related genes in qv3J TAC hearts. In vitro experiments demonstrated that βIV-spectrin serves as a target for CaMKII phosphorylation, which regulates its stability. Cardiac-specific βIV-spectrin-KO (βIV-cKO) mice showed STAT3 dysregulation, fibrosis, and decreased cardiac function at baseline, similar to what was observed with TAC in WT mice. STAT3 inhibition restored normal cardiac structure and function in βIV-cKO and WT TAC hearts. Our studies identify a spectrin-based complex essential for regulation of the cardiac response to chronic pressure overload. We anticipate that strategies targeting the new spectrin-based "statosome" will be effective at suppressing maladaptive remodeling in response to chronic stress.
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Affiliation(s)
- Sathya D Unudurthi
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Drew Nassal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Amara Greer-Short
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Nehal Patel
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Taylor Howard
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Xianyao Xu
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Birce Onal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Tony Satroplus
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Deborah Hong
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Cemantha Lane
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Alyssa Dalic
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Sara N Koenig
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Adam C Lehnig
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Lisa A Baer
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Hassan Musa
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Kristin I Stanford
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Sakima Smith
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Peter J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and.,Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Thomas J Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
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25
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Abraham DM, Lee TE, Watson LJ, Mao L, Chandok G, Wang HG, Frangakis S, Pitt GS, Shah SH, Wolf MJ, Rockman HA. The two-pore domain potassium channel TREK-1 mediates cardiac fibrosis and diastolic dysfunction. J Clin Invest 2018; 128:4843-4855. [PMID: 30153110 PMCID: PMC6205385 DOI: 10.1172/jci95945] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/23/2018] [Indexed: 01/08/2023] Open
Abstract
Cardiac two-pore domain potassium channels (K2P) exist in organisms from Drosophila to humans; however, their role in cardiac function is not known. We identified a K2P gene, CG8713 (sandman), in a Drosophila genetic screen and show that sandman is critical to cardiac function. Mice lacking an ortholog of sandman, TWIK-related potassium channel (TREK-1, also known Kcnk2), exhibit exaggerated pressure overload-induced concentric hypertrophy and alterations in fetal gene expression, yet retain preserved systolic and diastolic cardiac function. While cardiomyocyte-specific deletion of TREK-1 in response to in vivo pressure overload resulted in cardiac dysfunction, TREK-1 deletion in fibroblasts prevented deterioration in cardiac function. The absence of pressure overload-induced dysfunction in TREK-1-KO mice was associated with diminished cardiac fibrosis and reduced activation of JNK in cardiomyocytes and fibroblasts. These findings indicate a central role for cardiac fibroblast TREK-1 in the pathogenesis of pressure overload-induced cardiac dysfunction and serve as a conceptual basis for its inhibition as a potential therapy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Howard A Rockman
- Department of Medicine
- Department of Cell Biology, and
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
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26
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Nasr N, Faucherre A, Borsotto M, Heurteaux C, Mazella J, Jopling C, Moha Ou Maati H. Identification and characterization of two zebrafish Twik related potassium channels, Kcnk2a and Kcnk2b. Sci Rep 2018; 8:15311. [PMID: 30333618 PMCID: PMC6192994 DOI: 10.1038/s41598-018-33664-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/28/2018] [Indexed: 02/05/2023] Open
Abstract
KCNK2 is a 2 pore domain potassium channel involved in maintaining cellular membrane resting potentials. Although KCNK2 is regarded as a mechanosensitive ion channel, it can also be gated chemically. Previous research indicates that KCNK2 expression is particularly enriched in neuronal and cardiac tissues. In this respect, KCNK2 plays an important role in neuroprotection and has also been linked to cardiac arrhythmias. KCNK2 has subsequently become an attractive pharmacologic target for developing preventative/curative strategies for neuro/cardio pathophysiological conditions. Zebrafish represent an important in vivo model for rapidly analysing pharmacological compounds. We therefore sought to identify and characterise zebrafish kcnk2 to allow this model system to be incorporated into therapeutic research. Our data indicates that zebrafish possess two kcnk2 orthologs, kcnk2a and kcnk2b. Electrophysiological analysis of both zebrafish Kcnk2 orthologs shows that, like their human counterparts, they are activated by different physiological stimuli such as mechanical stretch, polyunsaturated fatty acids and intracellular acidification. Furthermore, both zebrafish Kcnk2 channels are inhibited by the human KCNK2 inhibitory peptide spadin. Taken together, our results demonstrate that both Kcnk2a and Kcnk2b share similar biophysiological and pharmacological properties to human KCNK2 and indicate that the zebrafish will be a useful model for developing KCNK2 targeting strategies.
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Affiliation(s)
- Nathalie Nasr
- IGF, CNRS, INSERM, Université de Montpellier, Labex ICST, F-34094, Montpellier, France
| | - Adèle Faucherre
- IGF, CNRS, INSERM, Université de Montpellier, Labex ICST, F-34094, Montpellier, France
| | - Marc Borsotto
- IPMC, CNRS, INSERM, Université de Nice Sophia Antipolis, Labex ICST, F-06560, Valbonne, France
| | - Catherine Heurteaux
- IPMC, CNRS, INSERM, Université de Nice Sophia Antipolis, Labex ICST, F-06560, Valbonne, France
| | - Jean Mazella
- IPMC, CNRS, INSERM, Université de Nice Sophia Antipolis, Labex ICST, F-06560, Valbonne, France
| | - Chris Jopling
- IGF, CNRS, INSERM, Université de Montpellier, Labex ICST, F-34094, Montpellier, France.
| | - Hamid Moha Ou Maati
- IGF, CNRS, INSERM, Université de Montpellier, Labex ICST, F-34094, Montpellier, France.
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27
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Vairamani K, Prasad V, Wang Y, Huang W, Chen Y, Medvedovic M, Lorenz JN, Shull GE. NBCe1 Na +-HCO3 - cotransporter ablation causes reduced apoptosis following cardiac ischemia-reperfusion injury in vivo. World J Cardiol 2018; 10:97-109. [PMID: 30344957 PMCID: PMC6189072 DOI: 10.4330/wjc.v10.i9.97] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/05/2018] [Accepted: 07/16/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the hypothesis that cardiomyocyte-specific loss of the electrogenic NBCe1 Na+-HCO3- cotransporter is cardioprotective during in vivo ischemia-reperfusion (IR) injury.
METHODS An NBCe1 (Slc4a4 gene) conditional knockout mouse (KO) model was prepared by gene targeting. Cardiovascular performance of wildtype (WT) and cardiac-specific NBCe1 KO mice was analyzed by intraventricular pressure measurements, and changes in cardiac gene expression were determined by RNA Seq analysis. Response to in vivo IR injury was analyzed after 30 min occlusion of the left anterior descending artery followed by 3 h of reperfusion.
RESULTS Loss of NBCe1 in cardiac myocytes did not impair cardiac contractility or relaxation under basal conditions or in response to β-adrenergic stimulation, and caused only limited changes in gene expression patterns, such as those for electrical excitability. However, following ischemia and reperfusion, KO heart sections exhibited significantly fewer apoptotic nuclei than WT sections.
CONCLUSION These studies indicate that cardiac-specific loss of NBCe1 does not impair cardiovascular performance, causes only minimal changes in gene expression patterns, and protects against IR injury in vivo .
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Affiliation(s)
- Kanimozhi Vairamani
- Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229-3026, United States
| | - Vikram Prasad
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229-3039, United States
| | - Yigang Wang
- Department of Pathology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0529, United States
| | - Wei Huang
- Department of Pathology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0529, United States
| | - Yinhua Chen
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229-3039, United States
| | - Mario Medvedovic
- Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, United States
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0575, United States
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0524, United States
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28
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Aziz Q, Finlay M, Montaigne D, Ojake L, Li Y, Anderson N, Ludwig A, Tinker A. ATP-sensitive potassium channels in the sinoatrial node contribute to heart rate control and adaptation to hypoxia. J Biol Chem 2018; 293:8912-8921. [PMID: 29666184 DOI: 10.1074/jbc.ra118.002775] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/16/2018] [Indexed: 11/06/2022] Open
Abstract
ATP-sensitive potassium channels (KATP) contribute to membrane currents in many tissues, are responsive to intracellular metabolism, and open as ATP falls and ADP rises. KATP channels are widely distributed in tissues and are prominently expressed in the heart. They have generally been observed in ventricular tissue, but they are also expressed in the atria and conduction tissues. In this study, we focused on the contribution and role of the inwardly rectifying KATP channel subunit, Kir6.1, in the sinoatrial node (SAN). To develop a murine, conduction-specific Kir6.1 KO model, we selectively deleted Kir6.1 in the conduction system in adult mice (cKO). Electrophysiological data in single SAN cells indicated that Kir6.1 underlies a KATP current in a significant proportion of cells and influences early repolarization during pacemaking, resulting in prolonged cycle length. Implanted telemetry probes to measure heart rate and electrocardiographic characteristics revealed that the cKO mice have a slow heart rate, with episodes of sinus arrest in some mice. The PR interval (time between the onset of the P wave to the beginning of QRS complex) was increased, suggesting effects on the atrioventricular node. Ex vivo studies of whole heart or dissected heart regions disclosed impaired adaptive responses of the SAN to hypoxia, and this may have had long-term pathological consequences in the cKO mice. In conclusion, Kir6.1-containing KATP channels in the SAN have a role in excitability, heart rate control, and the electrophysiological adaptation of the SAN to hypoxia.
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Affiliation(s)
- Qadeer Aziz
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom
| | - Malcolm Finlay
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom
| | - David Montaigne
- the Department of Clinical Physiology & Echocardiography, CHU Lille and the University of Lille, EGID, INSERM UMR1011, F-59000 Lille, France
| | - Leona Ojake
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom
| | - Yiwen Li
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom
| | - Naomi Anderson
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom
| | - Andreas Ludwig
- the Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany, and
| | - Andrew Tinker
- From the Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, United Kingdom,
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29
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Abstract
The Popeye domain containing (POPDC) genes encode transmembrane proteins, which are abundantly expressed in striated muscle cells. Hallmarks of the POPDC proteins are the presence of three transmembrane domains and the Popeye domain, which makes up a large part of the cytoplasmic portion of the protein and functions as a cAMP-binding domain. Interestingly, despite the prediction of structural similarity between the Popeye domain and other cAMP binding domains, at the protein sequence level they strongly differ from each other suggesting an independent evolutionary origin of POPDC proteins. Loss-of-function experiments in zebrafish and mouse established an important role of POPDC proteins for cardiac conduction and heart rate adaptation after stress. Loss-of function mutations in patients have been associated with limb-girdle muscular dystrophy and AV-block. These data suggest an important role of these proteins in the maintenance of structure and function of striated muscle cells.
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30
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Hund TJ, Unudurthi SD, Greer-Short A, Patel N, Nassal D. Spectrin-based pathways underlying electrical and mechanical dysfunction in cardiac disease. Expert Rev Cardiovasc Ther 2018; 16:59-65. [PMID: 29257730 PMCID: PMC6064643 DOI: 10.1080/14779072.2018.1418664] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION In the heart, pathways that transduce extracellular environmental cues (e.g. mechanical force, inflammatory stress) into electrical and/or chemical signals at the cellular level are critical for the organ-level response to chronic biomechanical/neurohumoral stress. Specifically, a diverse array of membrane-bound receptors and stretch-activated proteins converge on a network of intracellular signaling cascades that control gene expression, protein translation, degradation and/or regulation. These cellular reprogramming events ultimately lead to changes in cell excitability, growth, proliferation, and/or survival. Areas covered: The actin/spectrin cytoskeleton has emerged as having important roles in not only providing structural support for organelle function but also in serving as a signaling 'superhighway,' linking signaling events at/near the membrane to distal cellular domains (e.g. nucleus, mitochondria). Furthermore, recent work suggests that the integrity of the actin/spectrin cytoskeleton is critical for canonical signaling of pathways involved in cellular response to stress. This review discusses these emerging roles for spectrin and consider implications for heart function and disease. Expert commentary: Despite growth in our understanding of the broader roles for spectrins in cardiac myocytes and other metazoan cells, there remain important unanswered questions, the answers to which may point the way to new therapies for human cardiac disease patients.
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Affiliation(s)
- Thomas J. Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
- Department of Internal Medicine, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
| | - Sathya D. Unudurthi
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Amara Greer-Short
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Nehal Patel
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Drew Nassal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
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31
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Aziz Q, Li Y, Tinker A. Potassium channels in the sinoatrial node and their role in heart rate control. Channels (Austin) 2018; 12:356-366. [PMID: 30301404 PMCID: PMC6207292 DOI: 10.1080/19336950.2018.1532255] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 09/25/2018] [Accepted: 09/28/2018] [Indexed: 10/28/2022] Open
Abstract
Potassium currents determine the resting membrane potential and govern repolarisation in cardiac myocytes. Here, we review the various currents in the sinoatrial node focussing on their molecular and cellular properties and their role in pacemaking and heart rate control. We also describe how our recent finding of a novel ATP-sensitive potassium channel population in these cells fits into this picture.
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Affiliation(s)
- Qadeer Aziz
- William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Yiwen Li
- William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Andrew Tinker
- William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
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32
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Brand T, Schindler R. New kids on the block: The Popeye domain containing (POPDC) protein family acting as a novel class of cAMP effector proteins in striated muscle. Cell Signal 2017; 40:156-165. [PMID: 28939104 PMCID: PMC6562197 DOI: 10.1016/j.cellsig.2017.09.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 01/16/2023]
Abstract
The cyclic 3′,5′-adenosine monophosphate (cAMP) signalling pathway constitutes an ancient signal transduction pathway present in prokaryotes and eukaryotes. Previously, it was thought that in eukaryotes three effector proteins mediate cAMP signalling, namely protein kinase A (PKA), exchange factor directly activated by cAMP (EPAC) and the cyclic-nucleotide gated channels. However, recently a novel family of cAMP effector proteins emerged and was termed the Popeye domain containing (POPDC) family, which consists of three members POPDC1, POPDC2 and POPDC3. POPDC proteins are transmembrane proteins, which are abundantly present in striated and smooth muscle cells. POPDC proteins bind cAMP with high affinity comparable to PKA. Presently, their biochemical activity is poorly understood. However, mutational analysis in animal models as well as the disease phenotype observed in patients carrying missense mutations suggests that POPDC proteins are acting by modulating membrane trafficking of interacting proteins. In this review, we will describe the current knowledge about this gene family and also outline the apparent gaps in our understanding of their role in cAMP signalling and beyond. Popeye domain containing (POPDC) proteins are novel class of cAMP effector proteins. POPDC proteins control membrane trafficking of interacting proteins. POPDC proteins play a role in cardiac pacemaking and atrioventricular conduction. Mutations of POPDC genes are causing muscular dystrophy.
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Affiliation(s)
- Thomas Brand
- Developmental Dynamics, Myocardial Function, National Heart and Lung Institute, Imperial College London, United Kingdom.
| | - Roland Schindler
- Developmental Dynamics, Myocardial Function, National Heart and Lung Institute, Imperial College London, United Kingdom
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33
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Onal B, Gratz D, Hund TJ. Ca 2+/calmodulin-dependent kinase II-dependent regulation of atrial myocyte late Na + current, Ca 2+ cycling, and excitability: a mathematical modeling study. Am J Physiol Heart Circ Physiol 2017; 313:H1227-H1239. [PMID: 28842436 DOI: 10.1152/ajpheart.00185.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) affects more than three million people per year in the United States and is associated with high morbidity and mortality. Both electrical and structural remodeling contribute to AF, but the molecular pathways underlying AF pathogenesis are not well understood. Recently, a role for Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the regulation of persistent "late" Na+ current ( INa,L) has been identified. Although INa,L inhibition is emerging as a potential antiarrhythmic strategy in patients with AF, little is known about the mechanism linking INa,L to atrial arrhythmogenesis. A computational approach was used to test the hypothesis that increased CaMKII-activated INa,L in atrial myocytes disrupts Ca2+ homeostasis, promoting arrhythmogenic afterdepolarizations. Dynamic CaMKII activity and regulation of multiple downstream targets [ INa,L, L-type Ca2+ current, phospholamban, and the ryanodine receptor sarcoplasmic reticulum Ca2+-release channel (RyR2)] were incorporated into an existing well-validated computational model of the human atrial action potential. Model simulations showed that constitutive CaMKII-dependent phosphorylation of Nav1.5 and the subsequent increase in INa,L effectively disrupt intracellular atrial myocyte ion homeostasis and CaMKII signaling. Specifically, increased INa,L promotes intracellular Ca2+ overload via forward-mode Na+/Ca2+ exchange activity, which greatly increases RyR2 open probability beyond that observed for CaMKII-dependent phosphorylation of RyR2 alone. Increased INa,L promotes atrial myocyte repolarization defects (afterdepolarizations and alternans) in the setting of acute β-adrenergic stimulation. We anticipate that our modeling efforts will help identify new mechanisms for atrial NaV1.5 regulation with direct relevance for human AF. NEW & NOTEWORTHY Here, we present a novel computational model to study the effects of late Na+ current ( INa,L) in human atrial myocytes. Simulations predict that INa,L promotes intracellular accumulation of Ca2+, with subsequent dysregulation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) signaling and ryanodine receptor 2-mediated Ca2+ release. Although INa,L plays a small role in regulating atrial myocyte excitability at baseline, CaMKII-dependent enhancement of the current promoted arrhythmogenic dynamics. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/camkii-dependent-regulation-of-atrial-late-sodium-current-and-excitability/ .
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Affiliation(s)
- Birce Onal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Daniel Gratz
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio
| | - Thomas J Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, Ohio.,Department of Biomedical Engineering, College of Engineering, The Ohio State University , Columbus, Ohio.,Department of Internal Medicine, The Ohio State University Wexner Medical Center , Columbus, Ohio
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34
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Schmidt C, Wiedmann F, Kallenberger SM, Ratte A, Schulte JS, Scholz B, Müller FU, Voigt N, Zafeiriou MP, Ehrlich JR, Tochtermann U, Veres G, Ruhparwar A, Karck M, Katus HA, Thomas D. Stretch-activated two-pore-domain (K 2P) potassium channels in the heart: Focus on atrial fibrillation and heart failure. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:233-243. [PMID: 28526353 DOI: 10.1016/j.pbiomolbio.2017.05.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 12/18/2022]
Abstract
Two-pore-domain potassium (K2P) channels modulate cellular excitability. The significance of stretch-activated cardiac K2P channels (K2P2.1, TREK-1, KCNK2; K2P4.1, TRAAK, KCNK4; K2P10.1, TREK-2, KCNK10) in heart disease has not been elucidated in detail. The aim of this work was to assess expression and remodeling of mechanosensitive K2P channels in atrial fibrillation (AF) and heart failure (HF) patients in comparison to murine models. Cardiac K2P channel levels were quantified in atrial (A) and ventricular (V) tissue obtained from patients undergoing open heart surgery. In addition, control mice and mouse models of AF (cAMP-response element modulator (CREM)-IbΔC-X transgenic animals) or HF (cardiac dysfunction induced by transverse aortic constriction, TAC) were employed. Human and murine KCNK2 displayed highest mRNA abundance among mechanosensitive members of the K2P channel family (V > A). Disease-associated K2P2.1 remodeling was studied in detail. In patients with impaired left ventricular function, atrial KCNK2 (K2P2.1) mRNA and protein expression was significantly reduced. In AF subjects, downregulation of atrial and ventricular KCNK2 (K2P2.1) mRNA and protein levels was observed. AF-associated suppression of atrial Kcnk2 (K2P2.1) mRNA and protein was recapitulated in CREM-transgenic mice. Ventricular Kcnk2 expression was not significantly altered in mouse models of disease. In conclusion, mechanosensitive K2P2.1 and K2P10.1 K+ channels are expressed throughout the heart. HF- and AF-associated downregulation of KCNK2 (K2P2.1) mRNA and protein levels suggest a mechanistic contribution to cardiac arrhythmogenesis.
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Affiliation(s)
- Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Felix Wiedmann
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Stefan M Kallenberger
- Department for Bioinformatics and Functional Genomics, Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Antonius Ratte
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Jan S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Beatrix Scholz
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Maria-Patapia Zafeiriou
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Joachim R Ehrlich
- Department of Cardiology, Internal Medicine III, Goethe University, Frankfurt, Germany; Department of Cardiology, St. Josefs-Hospital, Wiesbaden, Germany
| | - Ursula Tochtermann
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Gábor Veres
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Arjang Ruhparwar
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Matthias Karck
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany.
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Decher N, Kiper AK, Rinné S. Stretch-activated potassium currents in the heart: Focus on TREK-1 and arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:223-232. [PMID: 28526352 DOI: 10.1016/j.pbiomolbio.2017.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 12/26/2022]
Abstract
This review focuses on the role and the molecular candidates of the cardiac stretch-activated potassium current (SAK). The functional properties of the two-pore domain potassium (K2P) channel TREK-1, a major candidate for the cardiac SAK, are analyzed and the molecular mechanism of stretch-activation in K2P potassium channels is discussed. Furthermore, the functional modulation of TREK-1 by different cardiac interaction partners, as well as evidence for the functional role of the stretch-dependent TREK-1 and its putative subunits in the heart is reviewed. In addition, we summarize the recent evidence that TREK-1 is involved in the pathogenesis of human cardiac arrhythmias.
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Affiliation(s)
- Niels Decher
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany.
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
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Abstract
Mathematical modeling has been used for over half a century to advance our understanding of cardiac electrophysiology and arrhythmia mechanisms. Notably, computational studies using mathematical models of the cardiac action potential (AP) have provided important insight into the fundamental nature of cell excitability, mechanisms underlying both acquired and inherited arrhythmia, and potential therapies. Ultimately, an approach that tightly integrates mathematical modeling and experimental techniques has great potential to accelerate discovery. Despite the increasing acceptance of mathematical modeling as a powerful tool in cardiac electrophysiology research, there remain significant barriers to its more widespread use in the field, due in part to the increasing complexity of models and growing need for specialization. To help bridge the gap between experimental and theoretical worlds that stands as a barrier to transformational breakthroughs, we present LongQt, which has the following key features: Cross-platform, threaded application with accessible graphical user interface. Facilitates advanced computational cardiac electrophysiology and arrhythmia studies. Does not require advanced programming skills.
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Affiliation(s)
- Birce Onal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Daniel Gratz
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Thomas Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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37
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Schindler RF, Scotton C, French V, Ferlini A, Brand T. The Popeye Domain Containing Genes and their Function in Striated Muscle. J Cardiovasc Dev Dis 2016; 3. [PMID: 27347491 PMCID: PMC4918794 DOI: 10.3390/jcdd3020022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/31/2016] [Accepted: 06/13/2016] [Indexed: 01/06/2023] Open
Abstract
The Popeye domain containing (POPDC) genes encode a novel class of cAMP effector proteins, which are abundantly expressed in heart and skeletal muscle. Here, we will review their role in striated muscle as deduced from work in cell and animal models and the recent analysis of patients carrying a missense mutation in POPDC1. Evidence suggests that POPDC proteins control membrane trafficking of interacting proteins. Furthermore, we will discuss the current catalogue of established protein-protein interactions. In recent years, the number of POPDC-interacting proteins has been rising and currently includes ion channels (TREK-1), sarcolemma-associated proteins serving functions in mechanical stability (dystrophin), compartmentalization (caveolin 3), scaffolding (ZO-1), trafficking (NDRG4, VAMP2/3) and repair (dysferlin) or acting as a guanine nucleotide exchange factor for Rho-family GTPases (GEFT). Recent evidence suggests that POPDC proteins might also control the cellular level of the nuclear proto-oncoprotein c-Myc. These data suggest that this family of cAMP-binding proteins probably serves multiple roles in striated muscle.
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Affiliation(s)
- Roland Fr Schindler
- Developmental Dynamics, Harefield Heart Science Centre, National Heart and Lung Institute, Imperial College London, Hill End Road, Harefield, UB9 6JH, United Kingdom
| | - Chiara Scotton
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Vanessa French
- Developmental Dynamics, Harefield Heart Science Centre, National Heart and Lung Institute, Imperial College London, Hill End Road, Harefield, UB9 6JH, United Kingdom
| | - Alessandra Ferlini
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Thomas Brand
- Developmental Dynamics, Harefield Heart Science Centre, National Heart and Lung Institute, Imperial College London, Hill End Road, Harefield, UB9 6JH, United Kingdom
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Unudurthi SD, Wu X, Qian L, Amari F, Onal B, Li N, Makara MA, Smith SA, Snyder J, Fedorov VV, Coppola V, Anderson ME, Mohler PJ, Hund TJ. Two-Pore K+ Channel TREK-1 Regulates Sinoatrial Node Membrane Excitability. J Am Heart Assoc 2016; 5:e002865. [PMID: 27098968 PMCID: PMC4859279 DOI: 10.1161/jaha.115.002865] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Two‐pore K+ channels have emerged as potential targets to selectively regulate cardiac cell membrane excitability; however, lack of specific inhibitors and relevant animal models has impeded the effort to understand the role of 2‐pore K+ channels in the heart and their potential as a therapeutic target. The objective of this study was to determine the role of mechanosensitive 2‐pore K+ channel family member TREK‐1 in control of cardiac excitability. Methods and Results Cardiac‐specific TREK‐1–deficient mice (αMHC‐Kcnkf/f) were generated and found to have a prevalent sinoatrial phenotype characterized by bradycardia with frequent episodes of sinus pause following stress. Action potential measurements from isolated αMHC‐Kcnk2f/f sinoatrial node cells demonstrated decreased background K+ current and abnormal sinoatrial cell membrane excitability. To identify novel pathways for regulating TREK‐1 activity and sinoatrial node excitability, mice expressing a truncated allele of the TREK‐1–associated cytoskeletal protein βIV‐spectrin (qv4J mice) were analyzed and found to display defects in cell electrophysiology as well as loss of normal TREK‐1 membrane localization. Finally, the βIV‐spectrin/TREK‐1 complex was found to be downregulated in the right atrium from a canine model of sinoatrial node dysfunction and in human cardiac disease. Conclusions These findings identify a TREK‐1–dependent pathway essential for normal sinoatrial node cell excitability that serves as a potential target for selectively regulating sinoatrial node cell function.
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Affiliation(s)
- Sathya D Unudurthi
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
| | - Xiangqiong Wu
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
| | - Lan Qian
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
| | - Foued Amari
- Department of Molecular Virology, Immunology & Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Birce Onal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
| | - Ning Li
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Michael A Makara
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Sakima A Smith
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Jedidiah Snyder
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
| | - Vadim V Fedorov
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Vincenzo Coppola
- Department of Molecular Virology, Immunology & Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Mark E Anderson
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Peter J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Thomas J Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH
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