1
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Li E, van der Heyden MAG. The network of cardiac K IR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-03116-5. [PMID: 38683369 DOI: 10.1007/s00210-024-03116-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands.
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2
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Arias-Santiago S, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular Kir2.1 C122Y Mutant Upsets Kir2.1-PIP 2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome. Circ Res 2024; 134:e52-e71. [PMID: 38497220 PMCID: PMC11009053 DOI: 10.1161/circresaha.123.323895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/29/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)122-to-Cys154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1C122Y variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments. RESULTS Kir2.1C122Y mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1C122Y cardiomyocytes showed significantly reduced inwardly rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and NaV1.5 proteins. CONCLUSIONS The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the NaV1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias-Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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3
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Collins NJ, Finn D, O'Mahony O, Walsh M. Survival in a young child with out-of-hospital cardiac arrest: diagnostic dilemma and when to deviate from standard resuscitation guidelines. BMJ Case Rep 2023; 16:e255729. [PMID: 37852665 PMCID: PMC10603545 DOI: 10.1136/bcr-2023-255729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023] Open
Abstract
A boy in early childhood presented in cardiac arrest. Care was provided out of hospital and in the emergency department as per standard paediatric resuscitation guidelines. Despite initial return of spontaneous circulation following cardiopulmonary resuscitation, two defibrillation shocks and epinephrine via intraosseous access, he had recurrent episodes of pulseless ventricular tachycardia and ventricular fibrillation. In total, 40 defibrillation shocks were administered, and he subsequently stabilised on combined treatment with intravenous esmolol, amiodarone and milrinone. He was transferred to the paediatric intensive care unit and had an automated implantable cardioverter-defibrillator inserted prior to discharge. Genetic testing has confirmed a diagnosis of catecholaminergic polymorphic ventricular tachycardia and it is hypothesised that the childhood excitement at a popular time of year, combined with caffeinated drinks, instigated his initial cardiac arrest which was propagated with iatrogenic epinephrine. He has remained stable since, with no neurological sequelae thus far from a significantly prolonged downtime.
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Affiliation(s)
- Neil John Collins
- Cardiac Services, The Royal Children's Hospital, Melbourne, Victoria, Australia
- Paediatrics, Cork University Hospital, Cork, Ireland
| | - Daragh Finn
- Paediatrics, Cork University Hospital, Cork, Ireland
| | | | - Mark Walsh
- Paediatric Cardiology, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
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4
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Santiago SA, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular cysteine disulfide bond break at Cys122 disrupts PIP 2-dependent Kir2.1 channel function and leads to arrhythmias in Andersen-Tawil Syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544151. [PMID: 37333254 PMCID: PMC10274791 DOI: 10.1101/2023.06.07.544151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Andersen-Tawil Syndrome Type 1 (ATS1) is a rare heritable disease caused by mutations in the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys122-to-Cys154 disulfide bond in the Kir2.1 channel structure is crucial for proper folding, but has not been associated with correct channel function at the membrane. We tested whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing the open state of the channel. Methods and Results We identified a Kir2.1 loss-of-function mutation in Cys122 (c.366 A>T; p.Cys122Tyr) in a family with ATS1. To study the consequences of this mutation on Kir2.1 function we generated a cardiac specific mouse model expressing the Kir2.1C122Y mutation. Kir2.1C122Y animals recapitulated the abnormal ECG features of ATS1, like QT prolongation, conduction defects, and increased arrhythmia susceptibility. Kir2.1C122Y mouse cardiomyocytes showed significantly reduced inward rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking ability and localization at the sarcolemma and the sarcoplasmic reticulum. Kir2.1C122Y formed heterotetramers with wildtype (WT) subunits. However, molecular dynamic modeling predicted that the Cys122-to-Cys154 disulfide-bond break induced by the C122Y mutation provoked a conformational change over the 2000 ns simulation, characterized by larger loss of the hydrogen bonds between Kir2.1 and phosphatidylinositol-4,5-bisphosphate (PIP2) than WT. Therefore, consistent with the inability of Kir2.1C122Y channels to bind directly to PIP2 in bioluminescence resonance energy transfer experiments, the PIP2 binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch-clamping the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing PIP2 concentrations. Conclusion The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential to channel function. We demonstrated that ATS1 mutations that break disulfide bonds in the extracellular domain disrupt PIP2-dependent regulation, leading to channel dysfunction and life-threatening arrhythmias.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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5
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Tembo M, Bainbridge RE, Lara-Santos C, Komondor KM, Daskivich GJ, Durrant JD, Rosenbaum JC, Carlson AE. Phosphate position is key in mediating transmembrane ion channel TMEM16A-phosphatidylinositol 4,5-bisphosphate interaction. J Biol Chem 2022; 298:102264. [PMID: 35843309 PMCID: PMC9396059 DOI: 10.1016/j.jbc.2022.102264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 02/07/2023] Open
Abstract
TransMEMbrane 16A (TMEM16A) is a Ca2+-activated Cl- channel that plays critical roles in regulating diverse physiologic processes, including vascular tone, sensory signal transduction, and mucosal secretion. In addition to Ca2+, TMEM16A activation requires the membrane lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). However, the structural determinants mediating this interaction are not clear. Here, we interrogated the parts of the PI(4,5)P2 head group that mediate its interaction with TMEM16A by using patch- and two-electrode voltage-clamp recordings on oocytes from the African clawed frog Xenopus laevis, which endogenously express TMEM16A channels. During continuous application of Ca2+ to excised inside-out patches, we found that TMEM16A-conducted currents decayed shortly after patch excision. Following this rundown, we show that the application of a synthetic PI(4,5)P2 analog produced current recovery. Furthermore, inducible dephosphorylation of PI(4,5)P2 reduces TMEM16A-conducted currents. Application of PIP2 analogs with different phosphate orientations yielded distinct amounts of current recovery, and only lipids that include a phosphate at the 4' position effectively recovered TMEM16A currents. Taken together, these findings improve our understanding of how PI(4,5)P2 binds to and potentiates TMEM16A channels.
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Affiliation(s)
- Maiwase Tembo
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rachel E Bainbridge
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Crystal Lara-Santos
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kayla M Komondor
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Grant J Daskivich
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jacob D Durrant
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Joel C Rosenbaum
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne E Carlson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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6
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Manuel AIM, Gutiérrez LK, Pedrosa MLV, Uréndez FMC, Jiménez FJB, Carrascoso IM, Pérez PS, Macías Á, Jalife J. Molecular stratification of arrhythmogenic mechanisms in the Andersen Tawil Syndrome. Cardiovasc Res 2022; 119:919-932. [PMID: 35892314 PMCID: PMC10153646 DOI: 10.1093/cvr/cvac118] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/20/2022] [Accepted: 07/01/2022] [Indexed: 11/12/2022] Open
Abstract
Andersen Tawil Syndrome (ATS) is a rare inheritable disease associated with loss-of-function mutations in KCNJ2, the gene coding the strong inward rectifier potassium channel Kir2.1, which forms an essential membrane protein controlling cardiac excitability. ATS is usually marked by a triad of periodic paralysis, life-threatening cardiac arrhythmias and dysmorphic features, but its expression is variable and not all patients with a phenotype linked to ATS have a known genetic alteration. The mechanisms underlying this arrhythmogenic syndrome are poorly understood. Knowing such mechanisms would be essential to distinguish ATS from other channelopathies with overlapping phenotypes and to develop individualized therapies. For example, the recently suggested role of Kir2.1 as a countercurrent to sarcoplasmic calcium reuptake might explain the arrhythmogenic mechanisms of ATS and its overlap with catecholaminergic polymorphic ventricular tachycardia (CPVT). Here we summarize current knowledge on the mechanisms of arrhythmias leading to sudden cardiac death in ATS. We first provide an overview of the syndrome and its pathophysiology, from the patient´s bedside to the protein, and discuss the role of essential regulators and interactors that could play a role in cases of ATS. The review highlights novel ideas related to some post-translational channel interactions with partner proteins that might help define the molecular bases of the arrhythmia phenotype. We then propose a new all-embracing classification of the currently known ATS loss-of-function mutations according to their position in the Kir2.1 channel structure and their functional implications. We also discuss specific ATS pathogenic variants, their clinical manifestations and treatment stratification. The goal is to provide a deeper mechanistic understanding of the syndrome toward the development of novel targets and personalized treatment strategies.
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Affiliation(s)
| | - Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | | | | | - Francisco José Bermúdez Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,Departamento de Cardiología, Hospital Virgen de las Nieves, GranadaSpain
| | | | - Patricia Sánchez Pérez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Departments of Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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7
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Le Tanno P, Folacci M, Revilloud J, Faivre L, Laurent G, Pinson L, Amedro P, Millat G, Janin A, Vivaudou M, Roux-Buisson N, Fauré J. Characterization of Loss-Of-Function KCNJ2 Mutations in Atypical Andersen Tawil Syndrome. Front Genet 2021; 12:773177. [PMID: 34899860 PMCID: PMC8655864 DOI: 10.3389/fgene.2021.773177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/03/2021] [Indexed: 12/02/2022] Open
Abstract
Andersen-Tawil Syndrome (ATS) is a rare disease defined by the association of cardiac arrhythmias, periodic paralysis and dysmorphic features, and is caused by KCNJ2 loss-of-function mutations. However, when extracardiac symptoms are atypical or absent, the patient can be diagnosed with Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), a rare arrhythmia at high risk of sudden death, mostly due to RYR2 mutations. The identification of KCNJ2 variants in CPVT suspicion is very rare but important because beta blockers, the cornerstone of CPVT therapy, could be less efficient. We report here the cases of two patients addressed for CPVT-like phenotypes. Genetic investigations led to the identification of p. Arg82Trp and p. Pro186Gln de novo variants in the KCNJ2 gene. Functional studies showed that both variants forms of Kir2.1 monomers act as dominant negative and drastically reduced the activity of the tetrameric channel. We characterize here a new pathogenic variant (p.Pro186Gln) of KCNJ2 gene and highlight the interest of accurate cardiologic evaluation and of attention to extracardiac signs to distinguish CPVT from atypical ATS, and guide therapeutic decisions. We also confirm that the KCNJ2 gene must be investigated during CPVT molecular analysis.
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Affiliation(s)
- Pauline Le Tanno
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Mathilde Folacci
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Jean Revilloud
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Laurence Faivre
- Medical Genetics Department, Dijon Bourgogne University Hospital, François Mitterand Hospital, Dijon, France
| | - Gabriel Laurent
- Cardiology Department, Dijon Bourgogne University Hospital, François Mitterand Hospital, Dijon, France
| | - Lucile Pinson
- Medical Genetics Department, University Hospital, Montpellier, France.,Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Montpellier, France.,Genetic Department for Rare Diseases and Personalized Medicine, Clinical Division, Montpellier, France
| | - Pascal Amedro
- Pediatric and Congenital Cardiology Department, Clinical Investigation Centre, PhyMedExp, CNRS, INSERM, University of Montpellier, University Hospital, Montpellier, France
| | - Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Alexandre Janin
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Michel Vivaudou
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Nathalie Roux-Buisson
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Julien Fauré
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
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8
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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9
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Chen S, Huang M, Hu X. Interference with KCNJ2 inhibits proliferation, migration and EMT progression of apillary thyroid carcinoma cells by upregulating GNG2 expression. Mol Med Rep 2021; 24:622. [PMID: 34212982 PMCID: PMC8261621 DOI: 10.3892/mmr.2021.12261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/15/2021] [Indexed: 12/12/2022] Open
Abstract
Papillary thyroid carcinoma is a common malignant tumor of the endocrine system. The specific role and molecular mechanism of potassium inwardly rectifying channel subfamily J member 2 (KCNJ2) in papillary thyroid carcinoma remain unknown. In the present study, the underlying mechanism of KCNJ2 in papillary thyroid carcinoma was explored. KCNJ2 expression in thyroid cancer tissues was predicted using the Gene Expression Profiling Interactive Analysis database, and reverse transcription‑quantitative PCR and western blot analyses were performed to detect KCNJ2 expression in papillary thyroid carcinoma cell lines. Cell transfection was performed to inhibit KCNJ2 and G protein subunit γ2 (GNG2) expression. In addition, cell proliferation was detected via the colony formation and MTT assays. The wound healing and Transwell assays were performed to assess cell migration and invasion, respectively. Western blot analysis was performed to detect the expression levels of transport‑related proteins and interstitial related proteins. The StarBase database was used to detect GNG2 expression in thyroid cancer. The results demonstrated that KCNJ2 expression was upregulated in papillary thyroid carcinoma cells. In addition, interfering with KCNJ2 expression inhibited the proliferation, invasion and migration of papillary thyroid carcinoma cells, and inhibited the epithelial‑to‑mesenchymal transition (EMT). These processes may be influenced by the upregulation of GNG2 expression induced by KCNJ2 knockdown. Overall , the results of the present study demonstrated that interference with KCNJ2 inhibited proliferation, migration and EMT progression of papillary thyroid carcinoma cells by upregulating GNG2 expression.
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Affiliation(s)
- Siyuan Chen
- The First Department of General Surgery, Affiliated Dongguan People's Hospital, Southern Medical University (Dongguan People's Hospital), Dongguan, Guangdong 523059, P.R. China
| | - Miaoming Huang
- Department of Otolaryngology, Affiliated Dongguan People's Hospital, Southern Medical University (Dongguan People's Hospital), Dongguan, Guangdong 523059, P.R. China
| | - Xiarong Hu
- The First Department of General Surgery, Affiliated Dongguan People's Hospital, Southern Medical University (Dongguan People's Hospital), Dongguan, Guangdong 523059, P.R. China
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Maggi L, Bonanno S, Altamura C, Desaphy JF. Ion Channel Gene Mutations Causing Skeletal Muscle Disorders: Pathomechanisms and Opportunities for Therapy. Cells 2021; 10:cells10061521. [PMID: 34208776 PMCID: PMC8234207 DOI: 10.3390/cells10061521] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/03/2021] [Accepted: 06/10/2021] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle ion channelopathies (SMICs) are a large heterogeneous group of rare genetic disorders caused by mutations in genes encoding ion channel subunits in the skeletal muscle mainly characterized by myotonia or periodic paralysis, potentially resulting in long-term disabilities. However, with the development of new molecular technologies, new genes and new phenotypes, including progressive myopathies, have been recently discovered, markedly increasing the complexity in the field. In this regard, new advances in SMICs show a less conventional role of ion channels in muscle cell division, proliferation, differentiation, and survival. Hence, SMICs represent an expanding and exciting field. Here, we review current knowledge of SMICs, with a description of their clinical phenotypes, cellular and molecular pathomechanisms, and available treatments.
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Affiliation(s)
- Lorenzo Maggi
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
- Correspondence:
| | - Silvia Bonanno
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
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11
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Wu L, Wang Q, Gu J, Zhang H, Gu Y. Modulation of Actin Filament Dynamics by Inward Rectifying of Potassium Channel Kir2.1. Int J Mol Sci 2020; 21:ijms21207479. [PMID: 33050503 PMCID: PMC7589188 DOI: 10.3390/ijms21207479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/02/2020] [Accepted: 10/06/2020] [Indexed: 01/17/2023] Open
Abstract
Apart from its ion channel properties, the Kir2.1 channel has been found in tumors and cancer cells to facilitate cancer cell motility. It is assumed that Kir2.1 might be associated with cell actin filament dynamics. With the help of structured illumination microscopy (SIM), we show that Kir2.1 overexpression promotes actin filament dynamics, cell invasion, and adhesion. Mutated Kir2.1 channels, with impaired membrane expression, present much weaker actin regulatory effects, which indicates that precise Kir2.1 membrane localization is key to its actin filament remolding effect. It is found that Kir2.1 membrane expression and anchoring are associated with PIP2 affinity, and PIP2 depletion inhibits actin filament dynamics. We also report that membrane-expressed Kir2.1 regulates redistribution and phosphorylation of FLNA (filamin A), which may be the mechanism underlying Kir2.1 and actin filament dynamics. In conclusion, Kir2.1 membrane localization regulates cell actin filaments, and not the ion channel properties. These data indicate that Kir2.1 may have additional cellular functions distinct from the regulation of excitability, which provides new insight into the study of channel proteins.
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Affiliation(s)
- Lida Wu
- Molecular Pharmacology Laboratory, Institute of Molecular Medicine, Peking University, Beijing 100871, China; (L.W.); (J.G.); (H.Z.)
- Aston Medical School, Aston University, Birmingham B4 7ET, UK
| | - Quanyi Wang
- Department of Biopharmaceutics, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China;
| | - Junzhong Gu
- Molecular Pharmacology Laboratory, Institute of Molecular Medicine, Peking University, Beijing 100871, China; (L.W.); (J.G.); (H.Z.)
| | - Huiyuan Zhang
- Molecular Pharmacology Laboratory, Institute of Molecular Medicine, Peking University, Beijing 100871, China; (L.W.); (J.G.); (H.Z.)
| | - Yuchun Gu
- Molecular Pharmacology Laboratory, Institute of Molecular Medicine, Peking University, Beijing 100871, China; (L.W.); (J.G.); (H.Z.)
- Aston Medical School, Aston University, Birmingham B4 7ET, UK
- Correspondence:
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