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Gessner G, Runge S, Koenen M, Heinemann SH, Koenen M, Haas J, Meder B, Thomas D, Katus HA, Schweizer PA. ANK2 functionally interacts with KCNH2 aggravating long QT syndrome in a double mutation carrier. Biochem Biophys Res Commun 2019; 512:845-851. [PMID: 30929919 DOI: 10.1016/j.bbrc.2019.03.162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 03/24/2019] [Indexed: 10/27/2022]
Abstract
Pathogenic long QT mutations often comprise high phenotypic variability and particularly variants in ANK2 (long QT syndrome 4) frequently lack QT prolongation. We sought to elucidate the genetic and functional background underlying the clinical diversity in a 3-generation family with different cardiac arrhythmias. Next-generation sequencing-based screening of patients with QT prolongation identified the index patient of the family carrying an ANK2-E1813K variant and a previously uncharacterized KCNH2-H562R mutation in a double heterozygous conformation. The patient presented with a severe clinical phenotype including a markedly prolonged QTc interval (544 ms), recurrent syncope due to Torsade de Pointes tachycardias, survived cardiopulmonary resuscitation, progressive cardiac conduction defect, and atrial fibrillation. Evaluation of other family members identified a sister and a niece solely carrying the ANK2-E1813K variant, who showed age-related conduction disease. An asymptomatic second sister solely carried the KCNH2-H562R mutation. Voltage-clamp recordings in Xenopus oocytes revealed that KCNH2-H562R subunits were non-functional but did not exert dominant-negative effects on wild-type subunits. Expression of KCNH2-H562R in HEK293 cells showed a trafficking deficiency. Co-expression of the C-terminal regulatory domain of ANK2 in Xenopus oocytes revealed that ANK2-E1813K diminished currents mediated by the combination of wild-type and H562R KCNH2 subunits. Our data suggest that ANK2 functionally interacts with KCNH2 leading to a stronger current suppression and marked aggravation of long QT syndrome in the patient carrying variants in both proteins.
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Affiliation(s)
- Guido Gessner
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-St. 2, D-07745, Jena, Germany
| | - Sarah Runge
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Michael Koenen
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstr. 29, D-69120, Heidelberg, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-St. 2, D-07745, Jena, Germany
| | - Mascha Koenen
- Institute for Comparative and Molecular Endocrinology, University of Ulm, Helmholtzstr. 8/1, D-89081, Ulm, Germany
| | - Jan Haas
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Benjamin Meder
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany
| | - Patrick A Schweizer
- Department of Cardiology, Medical University Hospital Heidelberg, INF 410, D-69120, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, INF 410, D-69120, Heidelberg, Germany.
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Zhang KP, Yang BF, Li BX. Translational toxicology and rescue strategies of the hERG channel dysfunction: biochemical and molecular mechanistic aspects. Acta Pharmacol Sin 2014; 35:1473-84. [PMID: 25418379 PMCID: PMC4261120 DOI: 10.1038/aps.2014.101] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/20/2014] [Indexed: 01/08/2023] Open
Abstract
The human ether-à-go-go related gene (hERG) potassium channel is an obligatory anti-target for drug development on account of its essential role in cardiac repolarization and its close association with arrhythmia. Diverse drugs have been removed from the market owing to their inhibitory activity on the hERG channel and their contribution to acquired long QT syndrome (LQTS). Moreover, mutations that cause hERG channel dysfunction may induce congenital LQTS. Recently, an increasing number of biochemical and molecular mechanisms underlying hERG-associated LQTS have been reported. In fact, numerous potential biochemical and molecular rescue strategies are hidden within the biogenesis and regulating network. So far, rescue strategies of hERG channel dysfunction and LQTS mainly include activators, blockers, and molecules that interfere with specific links and other mechanisms. The aim of this review is to discuss the rescue strategies based on hERG channel toxicology from the biochemical and molecular perspectives.
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Affiliation(s)
- Kai-ping Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
| | - Bao-feng Yang
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
| | - Bao-xin Li
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
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Large-scale mutational analysis of Kv11.1 reveals molecular insights into type 2 long QT syndrome. Nat Commun 2014; 5:5535. [PMID: 25417810 PMCID: PMC4243539 DOI: 10.1038/ncomms6535] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 10/09/2014] [Indexed: 12/23/2022] Open
Abstract
It has been suggested that deficient protein trafficking to the cell membrane is the dominant mechanism associated with type 2 Long QT syndrome (LQT2) caused by Kv11.1 potassium channel missense mutations, and that for many mutations the trafficking defect can be corrected pharmacologically. However, this inference was based on expression of a small number of Kv11.1 mutations. We performed a comprehensive analysis of 167 LQT2-linked missense mutations in four Kv11.1 structural domains and found that deficient protein trafficking is the dominant mechanism for all domains except for the distal carboxy-terminus. Also, most pore mutations--in contrast to intracellular domain mutations--were found to have severe dominant-negative effects when co-expressed with wild-type subunits. Finally, pharmacological correction of the trafficking defect in homomeric mutant channels was possible for mutations within all structural domains. However, pharmacological correction is dramatically improved for pore mutants when co-expressed with wild-type subunits to form heteromeric channels.
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Schlichter LC, Jiang J, Wang J, Newell EW, Tsui FWL, Lam D. Regulation of hERG and hEAG channels by Src and by SHP-1 tyrosine phosphatase via an ITIM region in the cyclic nucleotide binding domain. PLoS One 2014; 9:e90024. [PMID: 24587194 PMCID: PMC3938566 DOI: 10.1371/journal.pone.0090024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/31/2014] [Indexed: 12/14/2022] Open
Abstract
Members of the EAG K+ channel superfamily (EAG/Kv10.x, ERG/Kv11.x, ELK/Kv12.x subfamilies) are expressed in many cells and tissues. In particular, two prototypes, EAG1/Kv10.1/KCNH1 and ERG1/Kv11.1/KCNH2 contribute to both normal and pathological functions. Proliferation of numerous cancer cells depends on hEAG1, and in some cases, hERG. hERG is best known for contributing to the cardiac action potential, and for numerous channel mutations that underlie ‘long-QT syndrome’. Many cells, particularly cancer cells, express Src-family tyrosine kinases and SHP tyrosine phosphatases; and an imbalance in tyrosine phosphorylation can lead to malignancies, autoimmune diseases, and inflammatory disorders. Ion channel contributions to cell functions are governed, to a large degree, by post-translational modulation, especially phosphorylation. However, almost nothing is known about roles of specific tyrosine kinases and phosphatases in regulating K+ channels in the EAG superfamily. First, we show that tyrosine kinase inhibitor, PP1, and the selective Src inhibitory peptide, Src40-58, reduce the hERG current amplitude, without altering its voltage dependence or kinetics. PP1 similarly reduces the hEAG1 current. Surprisingly, an ‘immuno-receptor tyrosine inhibitory motif’ (ITIM) is present within the cyclic nucleotide binding domain of all EAG-superfamily members, and is conserved in the human, rat and mouse sequences. When tyrosine phosphorylated, this ITIM directly bound to and activated SHP-1 tyrosine phosphatase (PTP-1C/PTPN6/HCP); the first report that a portion of an ion channel is a binding site and activator of a tyrosine phosphatase. Both hERG and hEAG1 currents were decreased by applying active recombinant SHP-1, and increased by the inhibitory substrate-trapping SHP-1 mutant. Thus, hERG and hEAG1 currents are regulated by activated SHP-1, in a manner opposite to their regulation by Src. Given the widespread distribution of these channels, Src and SHP-1, this work has broad implications in cell signaling that controls survival, proliferation, differentiation, and other ERG1 and EAG1 functions in many cell types.
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Affiliation(s)
- Lyanne C. Schlichter
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology University of Toronto, Toronto, Ontario, Canada
- * E-mail:
| | - Jiahua Jiang
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - John Wang
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Evan W. Newell
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology University of Toronto, Toronto, Ontario, Canada
| | - Florence W. L. Tsui
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Doris Lam
- Genes and Development Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology University of Toronto, Toronto, Ontario, Canada
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Mechakra A, Vincent Y, Chevalier P, Millat G, Ficker E, Jastrzebski M, Poulin H, Pouliot V, Chahine M, Christé G. The variant hERG/R148W associated with LQTS is a mutation that reduces current density on co-expression with the WT. Gene 2013; 536:348-56. [PMID: 24334129 DOI: 10.1016/j.gene.2013.11.072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 11/08/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND A variant of the ether-à-go-go related channel (hERG), p.Arg148Trp (R148W) was found at heterozygous state in two infants who died from sudden infant death syndrome (SIDS), one with documented prolonged QTc and Torsade de Pointes (TdP), and in an adult woman with QTc >500 ms, atrioventricular block and TdP. This variant was previously reported in cases of severe ventricular arrhythmia but very rarely in control subjects. Its classification as mutation or polymorphism awaited electrophysiological characterization. METHODS The properties of this N-terminal, proximal domain, hERG variant were explored in Xenopus oocytes injected with the same amount of RNA encoding for either hERG/WT or hERG/R148W or their equimolar mixture. The human ventricular cell (TNNP) model was used to test the effects of changes in hERG current. RESULTS R148W alone produced a current similar to the WT (369 ± 76 nA (mean ± SEM), n=13 versus 342 ± 55 nA in WT, n=13), while the co-expression of 1/2 WT+1/2 R148W lowered the current by 29% versus WT (243 ± 35 nA, n=13, p<0.05). The voltage dependencies of steady-state activation and inactivation were not changed in the variant alone or in co-expression with the WT. The time constants of fast recovery from inactivation and of fast and slow deactivation analyzed between -120 and +20 mV were not changed. The voltage-dependent distribution of the current amplitudes among fast-, slow- and non-deactivating fractions was unaltered. A 6.6% increase in APD90 from 323.5 ms to 345 ms was observed using the human cardiac ventricular myocyte model. CONCLUSIONS Such a decrease in hERG current as evidenced here when co-expressing the hERG/R148W variant with the WT may have predisposed to the observed long QT syndrome and associated TdP. Therefore, the heterozygous carriers of hERG/R148W may be at risk of cardiac sudden death.
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Affiliation(s)
- Asma Mechakra
- Laboratoire de Neurocardiologie, EA4612, Université Lyon 1, Lyon F-69003, France
| | - Yohann Vincent
- Laboratoire de Neurocardiologie, EA4612, Université Lyon 1, Lyon F-69003, France
| | - Philippe Chevalier
- Laboratoire de Neurocardiologie, EA4612, Université Lyon 1, Lyon F-69003, France; Unité de Rythmologie, Centre National de Référence des Troubles du Rythme d'Origine Héréditaire, Hôpital Cardiovasculaire et Pneumologique L. Pradel, Hospices Civils de Lyon, Lyon F-69003, France
| | - Gilles Millat
- Laboratoire de Neurocardiologie, EA4612, Université Lyon 1, Lyon F-69003, France; Laboratoire de Cardiogénétique, Centre de Biologie Est, Hospices Civils de Lyon, Lyon F-69003, France
| | | | - Marek Jastrzebski
- Department of Cardiology and Hypertension, University Hospital, Kracow, Poland
| | - Hugo Poulin
- Le Centre de Recherche en neuroscience, Institut Universitaire en Santé Mentale de Québec and Department of Medicine, Laval University, Québec, Canada
| | - Valérie Pouliot
- Le Centre de Recherche en neuroscience, Institut Universitaire en Santé Mentale de Québec and Department of Medicine, Laval University, Québec, Canada
| | - Mohamed Chahine
- Le Centre de Recherche en neuroscience, Institut Universitaire en Santé Mentale de Québec and Department of Medicine, Laval University, Québec, Canada
| | - Georges Christé
- Laboratoire de Neurocardiologie, EA4612, Université Lyon 1, Lyon F-69003, France.
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He FZ, McLeod HL, Zhang W. Current pharmacogenomic studies on hERG potassium channels. Trends Mol Med 2013; 19:227-38. [PMID: 23369369 DOI: 10.1016/j.molmed.2012.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/18/2012] [Accepted: 12/27/2012] [Indexed: 11/25/2022]
Abstract
Genetic polymorphisms in human ether-a-go-go-related gene (hERG) potassium channels are associated with many complex diseases and sensitivity to channel-related drugs. Genotypes may underlie different sensitivities to the same drug, and different drugs selectively repair the functional deficits caused by individual mutations. In fact, not all drugs that block hERG function have adverse effects as previously thought. This suggests that the severe adverse reactions observed clinically may only occur in subjects with a particular genotype, but to others may be safe. Similarly, a drug that is ineffective in one population may be both safe and effective in another. Therefore, detecting polymorphisms in KCNH2 encoding hERG1 is of great significance in guiding the prevention and treatment of related diseases, re-evaluating drug safety, and individualizing treatment. This article reviews current pharmacogenomic studies on hERG potassium channels to provide a reference for developing individualized treatments and evaluating their safety.
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Affiliation(s)
- Fa-Zhong He
- Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, Hunan 410078, PR China
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Aidery P, Kisselbach J, Schweizer PA, Becker R, Katus HA, Thomas D. Impaired ion channel function related to a common KCNQ1 mutation — Implications for risk stratification in long QT syndrome 1. Gene 2012; 511:26-33. [DOI: 10.1016/j.gene.2012.09.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 11/28/2022]
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Kisselbach J, Schweizer PA, Gerstberger R, Becker R, Katus HA, Thomas D. Enhancement of K2P2.1 (TREK1) background currents expressed in Xenopus oocytes by voltage-gated K+ channel β subunits. Life Sci 2012; 91:377-383. [DOI: 10.1016/j.lfs.2012.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 07/17/2012] [Accepted: 08/02/2012] [Indexed: 11/26/2022]
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