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Fraile A, Cebrián J, Thuissard-Vasallo I, Pérez-Martín S, Casado R, Gil-Fournier B, Alonso-Martín J, Tamargo J, Caballero R, Delpón E, Cosío FG. Coexistent HCN4 and GATA5 rare variants and Atrial Fibrillation in a large Spanish Family. Can J Cardiol 2024:S0828-282X(24)00189-2. [PMID: 38432398 DOI: 10.1016/j.cjca.2024.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/02/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Familial association of atrial fibrillation (AF) can involve single gene variants related to known arrhythmogenic mechanisms; however, genome-wide association studies often disclose complex genetic variants in familial and non-familial AF, making it difficult to relate to known pathogenetic mechanisms. METHODS The finding of 4 siblings with AF led to studying 47 members of a family. Long-term Holter monitoring (298 hours average) ruled out silent AFWhole-exome sequencing was performed and variants shared by the index cases were filtered and prioritized according to current recommendations. HCN4 currents (IHCN4) were recorded in Chinese hamster ovary cells expressing human p.P1163H and/or native Hcn4 channels using the patch-clamp technique and topologically associated domain analysis of GATA5 variant carriers were performed. RESULTS The clinical study diagnosed 2 more AF cases. Five family members carried the heterozygous p.P1163H, HCN4 variant, 14 the intronic 20,61040536,G,A GATA5 rare variant, and 9 carried both variants (HCN4+GATA5). Five of the 6 AF cases (onset age ranging 33-70 years) carried both variants and one the GATA5 variant alone. Multivariate analysis showed that the presence of HCN4+GATA5 variants significantly and independently increased AF risk [OR=32.740 (1.812-591.408)] and not age, hypertension or overweight. Functional testing showed that IHcn4 generated by heterozygous p.P1163H were normal. Topologically associating domain analysis suggested that GATA5 could affect the expression of many genes, including those encoding microRNA-1. CONCLUSION The coincidence of two rare gene variants was independently associated with AF, but functional studies do not allow the postulation of the arrhythmogenic mechanism(s) involved.
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Affiliation(s)
- Alfonso Fraile
- Cardiology Department. Hospital Universitario de Getafe. Carretera de Toledo, Km. 12,500. 28905-Getafe, Spain.
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Israel Thuissard-Vasallo
- Department of Biomedical and Health Sciences. Universidad Europea de Madrid. 28670-Madrid, Spain
| | - Sara Pérez-Martín
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Raquel Casado
- Cardiology Department. Hospital Universitario de Getafe. Carretera de Toledo, Km. 12,500. 28905-Getafe, Spain
| | - Belen Gil-Fournier
- Cardiology Department. Hospital Universitario de Getafe. Carretera de Toledo, Km. 12,500. 28905-Getafe, Spain
| | - Joaquín Alonso-Martín
- Cardiology Department. Hospital Universitario de Getafe. Carretera de Toledo, Km. 12,500. 28905-Getafe, Spain
| | - Juan Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain.
| | - Eva Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Francisco G Cosío
- Department of Biomedical and Health Sciences. Universidad Europea de Madrid. 28670-Madrid, Spain
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Benzoni P, Gazzerro E, Fiorillo C, Baratto S, Bartolucci C, Severi S, Milanesi R, Lippi M, Langione M, Murano C, Meoni C, Popolizio V, Cospito A, Baruscotti M, Bucchi A, Barbuti A. Caveolin-3 and Caveolin-1 Interaction Decreases Channel Dysfunction Due to Caveolin-3 Mutations. Int J Mol Sci 2024; 25:980. [PMID: 38256054 PMCID: PMC10816214 DOI: 10.3390/ijms25020980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Caveolae constitute membrane microdomains where receptors and ion channels functionally interact. Caveolin-3 (cav-3) is the key structural component of muscular caveolae. Mutations in CAV3 lead to caveolinopathies, which result in both muscular dystrophies and cardiac diseases. In cardiomyocytes, cav-1 participates with cav-3 to form caveolae; skeletal myotubes and adult skeletal fibers do not express cav-1. In the heart, the absence of cardiac alterations in the majority of cases may depend on a conserved organization of caveolae thanks to the expression of cav-1. We decided to focus on three specific cav-3 mutations (Δ62-64YTT; T78K and W101C) found in heterozygosis in patients suffering from skeletal muscle disorders. We overexpressed both the WT and mutated cav-3 together with ion channels interacting with and modulated by cav-3. Patch-clamp analysis conducted in caveolin-free cells (MEF-KO), revealed that the T78K mutant is dominant negative, causing its intracellular retention together with cav-3 WT, and inducing a significant reduction in current densities of all three ion channels tested. The other cav-3 mutations did not cause significant alterations. Mathematical modelling of the effects of cav-3 T78K would impair repolarization to levels incompatible with life. For this reason, we decided to compare the effects of this mutation in other cell lines that endogenously express cav-1 (MEF-STO and CHO cells) and to modulate cav-1 expression with an shRNA approach. In these systems, the membrane localization of cav-3 T78K was rescued in the presence of cav-1, and the current densities of hHCN4, hKv1.5 and hKir2.1 were also rescued. These results constitute the first evidence of a compensatory role of cav-1 in the heart, justifying the reduced susceptibility of this organ to caveolinopathies.
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Affiliation(s)
- Patrizia Benzoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Elisabetta Gazzerro
- Unit of Muscle Research, Experimental and Clinical Research Center, Cooperation between the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and Charité-University Berlin, 13125 Berlin, Germany
| | - Chiara Fiorillo
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, DINOGMI-University of Genova, 16147 Genova, Italy
| | - Serena Baratto
- Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Chiara Bartolucci
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, 47521 Cesena, Italy
| | - Stefano Severi
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, 47521 Cesena, Italy
| | - Raffaella Milanesi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Melania Lippi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Marianna Langione
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Carmen Murano
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Clarissa Meoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Vera Popolizio
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Alessandro Cospito
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Mirko Baruscotti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Annalisa Bucchi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
| | - Andrea Barbuti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, 20133 Milan, Italy
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3
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Nguyen LH, Xu Y, Nair M, Bordey A. The mTOR pathway genes mTOR, Rheb, Depdc5, Pten, and Tsc1 have convergent and divergent impacts on cortical neuron development and function. bioRxiv 2024:2023.08.11.553034. [PMID: 37609221 PMCID: PMC10441381 DOI: 10.1101/2023.08.11.553034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Brain somatic mutations in various components of the mTOR complex 1 (mTORC1) pathway have emerged as major causes of focal malformations of cortical development and intractable epilepsy. While these distinct gene mutations converge on excessive mTORC1 signaling and lead to common clinical manifestations, it remains unclear whether they cause similar cellular and synaptic disruptions underlying cortical network hyperexcitability. Here, we show that in utero activation of the mTORC1 activators, Rheb or mTOR, or biallelic inactivation of the mTORC1 repressors, Depdc5, Tsc1, or Pten in mouse medial prefrontal cortex leads to shared alterations in pyramidal neuron morphology, positioning, and membrane excitability but different changes in excitatory synaptic transmission. Our findings suggest that, despite converging on mTORC1 signaling, mutations in different mTORC1 pathway genes differentially impact cortical excitatory synaptic activity, which may confer gene-specific mechanisms of hyperexcitability and responses to therapeutic intervention.
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Affiliation(s)
- Lena H. Nguyen
- Department Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Youfen Xu
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Maanasi Nair
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
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Cámara-Checa A, Perin F, Rubio-Alarcón M, Dago M, Crespo-García T, Rapún J, Marín M, Cebrián J, Gómez R, Bermúdez-Jiménez F, Monserrat L, Tamargo J, Caballero R, Jiménez-Jáimez J, Delpón E. A gain-of-function HCN4 mutant in the HCN domain is responsible for inappropriate sinus tachycardia in a Spanish family. Proc Natl Acad Sci U S A 2023; 120:e2305135120. [PMID: 38032931 DOI: 10.1073/pnas.2305135120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/12/2023] [Indexed: 12/02/2023] Open
Abstract
In a family with inappropriate sinus tachycardia (IST), we identified a mutation (p.V240M) of the hyperpolarization-activated cyclic nucleotide-gated type 4 (HCN4) channel, which contributes to the pacemaker current (If) in human sinoatrial node cells. Here, we clinically study fifteen family members and functionally analyze the p.V240M variant. Macroscopic (IHCN4) and single-channel currents were recorded using patch-clamp in cells expressing human native (WT) and/or p.V240M HCN4 channels. All p.V240M mutation carriers exhibited IST that was accompanied by cardiomyopathy in adults. IHCN4 generated by p.V240M channels either alone or in combination with WT was significantly greater than that generated by WT channels alone. The variant, which lies in the N-terminal HCN domain, increased the single-channel conductance and opening frequency and probability of HCN4 channels. Conversely, it did not modify the channel sensitivity for cAMP and ivabradine or the level of expression at the membrane. Treatment with ivabradine based on functional data reversed the IST and the cardiomyopathy of the carriers. In computer simulations, the p.V240M gain-of-function variant increases If and beating rate and thus explains the IST of the carriers. The results demonstrate the importance of the unique HCN domain in HCN4, which stabilizes the channels in the closed state.
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Affiliation(s)
- Anabel Cámara-Checa
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Francesca Perin
- Department of Pediatric Cardiology, Virgen de las Nieves University Hospital, Granada 18014, Spain
- Instituto de Investigación Biosanitaria de Granada, Granada 18014, Spain
| | - Marcos Rubio-Alarcón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - María Dago
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Teresa Crespo-García
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Josu Rapún
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - María Marín
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Ricardo Gómez
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Francisco Bermúdez-Jiménez
- Department of Pediatric Cardiology, Virgen de las Nieves University Hospital, Granada 18014, Spain
- Instituto de Investigación Biosanitaria de Granada, Granada 18014, Spain
- Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain
| | - Lorenzo Monserrat
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
- Health in Code Sociedad Limitada, A Coruña 15008, Spain
| | - Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Juan Jiménez-Jáimez
- Department of Pediatric Cardiology, Virgen de las Nieves University Hospital, Granada 18014, Spain
- Instituto de Investigación Biosanitaria de Granada, Granada 18014, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Instituto de Salud Carlos III, Madrid 28029, Spain
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5
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Chaudhry-Waterman N, Dara B, Bucholz E, Londono Obregon C, Grenier M, Snyder K, Cuneo BF. Fetal Heart Rate < 3rd Percentile for Gestational Age Can Be a Marker of Inherited Arrhythmia Syndromes. J Clin Med 2023; 12:4464. [PMID: 37445499 DOI: 10.3390/jcm12134464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/16/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND Repeated fetal heart rates (FHR) < 3rd percentile for gestational age (GA) with 1:1 atrioventricular conduction (sinus bradycardia) can be a marker for long QT syndrome. We hypothesized that other inherited arrhythmia syndromes might present with fetal sinus bradycardia. METHODS We reviewed pregnancies referred with sinus bradycardia to the Colorado Fetal Care Center between 2013 and 2023. FHR/GA data, family history, medication exposure, normalized isovolumic contraction times (n-IVRT), postnatal genetic testing, and ECGs at 4-6 weeks after birth were reviewed. RESULTS Twenty-nine bradycardic subjects were evaluated by fetal echocardiography. Five were lost to follow-up, one refused genetic testing, and one had negative genetic testing for any inherited arrhythmia. Six had non-genetic causes of fetal bradycardia with normal prenatal n-IVRT and postnatal QTc. Thirteen carried pathogenic variants in RYR2 (n = 2), HCN4 (n = 2), KCNQ1 (6), and other LQTS genes (n = 4). The postnatal QTc was <470 ms in subjects with RYR2, HCN4, and two of those with KCNQ1 mutations, and >470 ms in subjects with CALM 2, KCNH2, SCN5A, and four of those with KCNQ1 mutations. LQTS and RYR2 mutations were associated with prolonged n-IVRT, but HCN4 was not. Two fetuses died in utero with variants of uncertain significance (CACNA1 and KCNE1). Cascade testing uncovered six affected but undiagnosed parents and confirmed familial inheritance in five. CONCLUSION In addition to heralding LQTS, repeated FHR < 3rd percentile for GA is a risk factor for other inherited arrhythmia syndromes. These findings suggest that genetic testing should be offered to infants with a history of FHR < 3rd percentile for GA even if the postnatal ECG demonstrates a normal QTc interval.
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Affiliation(s)
- Nadia Chaudhry-Waterman
- The Division of Cardiology, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80045, USA
| | - Bharat Dara
- Presbyterian Hospital, Albuquerque, NM 87106, USA
| | - Emily Bucholz
- The Division of Cardiology, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80045, USA
- The Colorado Fetal Care Center, Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Camila Londono Obregon
- The Division of Cardiology, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80045, USA
- The Colorado Fetal Care Center, Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Michelle Grenier
- The Division of Cardiology, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80045, USA
- The Colorado Fetal Care Center, Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Kristen Snyder
- The Colorado Fetal Care Center, Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Bettina F Cuneo
- The Division of Cardiology, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80045, USA
- The Colorado Fetal Care Center, Children's Hospital Colorado, Aurora, CO 80045, USA
- The Department of Obstetrics, University of Colorado School of Medicine, Denver, CO 80045, USA
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6
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Duan S, Du J. Sinus node dysfunction and atrial fibrillation-Relationships, clinical phenotypes, new mechanisms, and treatment approaches. Ageing Res Rev 2023; 86:101890. [PMID: 36813137 DOI: 10.1016/j.arr.2023.101890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023]
Abstract
Although the anatomical basis of the pathogenesis of sinus node dysfunction (SND) and atrial fibrillation (AF) is located primarily in the left and right atria, increasing evidence suggests a strong correlation between SND and AF, in terms of both clinical presentation and formation mechanisms. However, the exact mechanisms underlying this association are unclear. The relationship between SND and AF may not be causal, but is likely to involve common factors and mechanisms, including ion channel remodeling, gap junction abnormalities, structural remodeling, genetic mutations, neuromodulation abnormalities, the effects of adenosine on cardiomyocytes, oxidative stress, and viral infections. Ion channel remodeling manifests primarily as alterations in the "funny" current (If) and Ca2+ clock associated with cardiomyocyte autoregulation, and gap junction abnormalities are manifested primarily as decreased expression of connexins (Cxs) mediating electrical impulse propagation in cardiomyocytes. Structural remodeling refers primarily to fibrosis and cardiac amyloidosis (CA). Some genetic mutations can also cause arrhythmias, such as SCN5A, HCN4, EMD, and PITX2. The intrinsic cardiac autonomic nervous system (ICANS), a regulator of the heart's physiological functions, triggers arrhythmias.In addition, we discuss arrhythmias caused by viral infections, notably Coronavirus Disease 2019 (COVID-19). Similarly to upstream treatments for atrial cardiomyopathy such as alleviating CA, ganglionated plexus (GP) ablation acts on the common mechanisms between SND and AF, thus achieving a dual therapeutic effect.
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7
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Patberg M, Oniani T, Disse P, Peischard S, Vinnenberg L, Zobeiri M, Romanelli MN, Epping L, Wiendl H, Meuth SG, Hundehege P, Seebohm G, Budde T, Junker A. Optimized synthesis and pharmacological evaluation of HCN channel inhibitor EC18. Arch Pharm (Weinheim) 2023:e2200665. [PMID: 36949271 DOI: 10.1002/ardp.202200665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/24/2023]
Abstract
HCN4 channels are considered to be a promising target for cardiac pathologies, epilepsy, and multiple sclerosis. However, there are no subtype-selective HCN channel blockers available, and only a few compounds are reported to display subtype preferences, one of which is EC18 (cis-1). Herein, we report the optimized synthetic route for the preparation of EC18 and its evaluation in three different pharmacological models, allowing us to assess its activity on cardiac function, thalamocortical neurons, and immune cells.
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Affiliation(s)
- Marius Patberg
- European Institute for Molecular Imaging (EIMI), Münster, Germany
| | | | - Paul Disse
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University of Münster, Münster, Germany
| | - Stefan Peischard
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University of Münster, Münster, Germany
| | - Laura Vinnenberg
- Klinik für Neurologie mit Institut für Translationale Neurologie, ICB, Münster, Germany
| | | | - Maria N Romanelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Lisa Epping
- Klinik für Neurologie mit Institut für Translationale Neurologie, ICB, Münster, Germany
| | - Heinz Wiendl
- Klinik für Neurologie mit Institut für Translationale Neurologie, ICB, Münster, Germany
| | - Sven G Meuth
- Universitätsklinikum Düsseldorf, Medizinische Fakultät, Klinik für Neurologie, Düsseldorf, Germany
| | - Petra Hundehege
- Klinik für Neurologie mit Institut für Translationale Neurologie, ICB, Münster, Germany
| | - Guiscard Seebohm
- Cellular Electrophysiology and Molecular Biology, Institute for Genetics of Heart Diseases (IfGH), University of Münster, Münster, Germany
| | | | - Anna Junker
- European Institute for Molecular Imaging (EIMI), Münster, Germany
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8
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Yildirim Z, Kojic A, Yan CD, Wu MA, Vagelos R, Wu JC. Generation of two induced pluripotent stem cell lines from dilated cardiomyopathy patients caused by heterozygous mutations in the HCN4 gene. Stem Cell Res 2022; 65:102951. [PMID: 36332467 DOI: 10.1016/j.scr.2022.102951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/10/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a progressive heart muscle disease that can culminate with heart failure and death. Mutations in several genes can cause DCM, including hyperpolarization-activated cyclic nucleotide-gated channel (HCN4), which has a critical function in the autonomic control of the heart rate. Here, we generated two human induced pluripotent stem cell (iPSC) lines generated from two DCM patients carrying variants in the HCN4 gene (c.2587G > T and c.2846G > A). Both lines display normal karyotype, typical morphology of pluripotent stem cells, and differentiate into all three germ layers in vitro. These lines are valuable resources for studying the pathological mechanisms of DCM.
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9
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Saponaro A, Thiel G, Moroni A. Structural and functional approaches to studying cAMP regulation of HCN channels. Biochem Soc Trans 2021; 49:2573-9. [PMID: 34812892 DOI: 10.1042/BST20210290] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are primarily activated by voltage and further modulated by cAMP. While cAMP binding alone does not open the channel, its presence facilitates the action of voltage, increasing channel open probability. Functional results indicate that the membrane-based voltage sensor domain (VSD) communicates with the cytosolic cyclic nucleotide-binding domain (CNBD), and vice-versa. Yet, a mechanistic explanation on how this could occur in structural terms is still lacking. In this review, we will discuss the recent advancement in understanding the molecular mechanisms connecting the VSD with the CNBD in the tetrameric organization of HCN channels unveiled by the 3D structures of HCN1 and HCN4. Data show that the HCN domain transmits cAMP signal to the VSD by bridging the cytosolic to the membrane domains. Furthermore, a metal ion coordination site connects the C-linker to the S4-S5 linker in HCN4, further facilitating cAMP signal transmission to the VSD in this isoform.
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Rodríguez-Angulo HO, Colombet-Naranjo D, Maza MC, Poveda C, Herreros-Cabello A, Mendoza I, Perera JC, Goyo JD, Gironès N, Fresno M. Molecular Remodeling of Cardiac Sinus Node Associated with Acute Chagas Disease Myocarditis. Microorganisms 2021; 9:microorganisms9112208. [PMID: 34835334 PMCID: PMC8620628 DOI: 10.3390/microorganisms9112208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 01/04/2023] Open
Abstract
Chagas disease principally affects Latin-American people, but it currently has worldwide distribution due to migration. Death among those with Chagas disease can occur suddenly and without warning, even in those who may not have evidence of clinical or structural cardiac disease and who are younger than 60 years old. HCN4 channels, one of the principal elements responsible for pacemaker currents, are associated with cardiac fetal reprogramming and supraventricular and ventricular arrhythmias, but their role in chagasic arrhythmias is not clear. We found that a single-dose administration of ivabradine, which blocks HCN4, caused QTc and QRS enlargement and an increase in P-wave amplitude and was associated with ventricular and supraventricular arrhythmias in mice challenged with isoproterenol, a chronotropic/ionotropic positive agent. Continuous treatment with ivabradine did not alter the QTc interval, but P-wave morphology was deeply modified, generating supraventricular arrhythmias. In addition, we found that repolarization parameters improved with ivabradine treatment. These effects could have been caused by the high HCN4 expression observed in auricular and ventricular tissue in infected mice. Thus, we suggest, for the first time, that molecular remodeling by overexpression of HCN4 channels may be related to supraventricular arrhythmias in acute Chagas disease, causing ivabradine over-response. Thus, ivabradine treatment should be administered with caution, while HCN4 overexpression may be an indicator of heart failure and/or sudden death risk.
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Affiliation(s)
- Héctor O. Rodríguez-Angulo
- Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela; (H.O.R.A.); (D.C.-N.)
- Unidad de Biología Celular, Departamento de Ciencias Morfológicas, Programa de Medicina, Facultad de Ciencias de la vida, Universidad Centroccidental Lisandro Alvarado, Barquisimeto 3001, Venezuela; (J.C.P.); (J.D.G.)
| | - Diana Colombet-Naranjo
- Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela; (H.O.R.A.); (D.C.-N.)
| | - María C. Maza
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.C.M.); (C.P.); (A.-H.C.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Cristina Poveda
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.C.M.); (C.P.); (A.-H.C.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Alfonso Herreros-Cabello
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.C.M.); (C.P.); (A.-H.C.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Iván Mendoza
- Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas 1060, Venezuela;
| | - Juan C. Perera
- Unidad de Biología Celular, Departamento de Ciencias Morfológicas, Programa de Medicina, Facultad de Ciencias de la vida, Universidad Centroccidental Lisandro Alvarado, Barquisimeto 3001, Venezuela; (J.C.P.); (J.D.G.)
| | - Juan D. Goyo
- Unidad de Biología Celular, Departamento de Ciencias Morfológicas, Programa de Medicina, Facultad de Ciencias de la vida, Universidad Centroccidental Lisandro Alvarado, Barquisimeto 3001, Venezuela; (J.C.P.); (J.D.G.)
| | - Núria Gironès
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.C.M.); (C.P.); (A.-H.C.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria Hospital Universitario de la Princesa, 28009 Madrid, Spain
- Correspondence: (N.G.); (M.F.)
| | - Manuel Fresno
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.C.M.); (C.P.); (A.-H.C.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria Hospital Universitario de la Princesa, 28009 Madrid, Spain
- Correspondence: (N.G.); (M.F.)
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11
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Yu H, Gall B, Newman M, Hathaway Q, Brundage K, Ammer A, Mathers P, Siderovski D, Hull RW. Contribution of HCN1 variant to sinus bradycardia: A case report. J Arrhythm 2021; 37:1337-1347. [PMID: 34621433 PMCID: PMC8485797 DOI: 10.1002/joa3.12598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/08/2021] [Accepted: 06/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Missense mutations in the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel 4 (HCN4) are one of the genetic causes of cardiac sinus bradycardia. OBJECTIVE To investigate possible HCN4 channel mutation in a young patient with profound sinus bradycardia. METHODS Direct sequencing of HCN4 and whole-exome sequencing were performed on DNA samples from the indexed patient (P), the patient's son (PS), and a family unrelated healthy long-distance running volunteer (V). Resting heart rate was 31 bpm for P, 67 bpm for PS, and 50 bpm for V. Immunoblots, flow cytometry, and immunocytofluorescence confocal imaging were used to study cellular distribution of channel variants. Patch-clamp electrophysiology was used to investigate the properties of mutant HCN1 channels. RESULTS In P no missense mutations were found in the HCN4 gene; instead, we found two heterozygous variants in the HCN1 gene: deletion of an N-terminal glycine triplet (72GGG74, "N-del") and a novel missense variant, P851A, in the C-terminal region. N-del variant was found before and shared by PS. These two variations were not found in V. Compared to wild type, N-del and P851A reduced cell surface expression and negatively shifted voltage-activation with slower activation kinetics. CONCLUSION Decreased channel activity HCN1 mutant channel makes it unable to contribute to early depolarization of sinus node action potential, thus likely a main cause of the profound sinus bradycardia in this patient.
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Affiliation(s)
- Hangang Yu
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Bryan Gall
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Variant Curator at NateraSan CarlosCAUSA
| | - Mackenzie Newman
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Quincy Hathaway
- Department of Exercise PhysiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Kathleen Brundage
- Department of Microbiology, Immunology & Cell BiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Amanda Ammer
- Department of Microbiology, Immunology & Cell BiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Peter Mathers
- Department of NeuroscienceSchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - David Siderovski
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Pharmacology & NeuroscienceUniversity of North TexasDentonTXUSA
| | - Robert W. Hull
- Department of CardiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Department of CardiologyMon General HospitalMorgantownWVUSA
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12
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Zhang H, Li L, Hao M, Chen K, Lu Y, Qi J, Chen W, Ren L, Cai X, Chen C, Liu Z, Zhao B, Li Z, Hou P. Yixin-Fumai granules improve sick sinus syndrome in aging mice through Nrf-2/HO-1 pathway: A new target for sick sinus syndrome. J Ethnopharmacol 2021; 277:114254. [PMID: 34062246 DOI: 10.1016/j.jep.2021.114254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/13/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Yixin-Fumai granules (YXFMs)-composed of Ginseng quinquefolium (L.) Alph. Wood, Ophiopogon japonicus (Thunb.) Ker Gawl, Schisandra arisanensis Hayata, Astragalus aaronsohnianus Eig, Salvia cryptantha Montbret & Aucher ex Benth, and Ligusticum striatum DC-are compound granules used in traditional Chinese medicine to increase heart rate and thus treat bradyarrhythmia. It may be effective in treating sick sinus syndrome (SSS). AIM To observe the effect of YXFMs on aging-induced SSS in mice and explore whether this effect is related to the Nrf-2/HO-1 signaling pathway. MATERIALS AND METHODS Mice with a significant decrease in the heart rate due to natural aging were selected to construct an SSS model. After the mice were administered YXFMs, the damage to their sinoartrial node (SAN) was assessed through electrocardiography, Masson's trichrome staining, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Dihydroethidium staining and immunofluorescence staining were used to assay reactive oxygen species (ROS) content and HCN4, respectively. Moreover, to observe the effects of YXFMs in vitro, the HL-1 cell line, derived from mouse atrial myocytes, was used to simulate SAN pacemaker cells, with H2O2 used as the cellular oxidative stress (OS) inducer. 2,7-Dichlorodihydrofluorescein diacetate staining was used to assay ROS content, whereas immunofluorescence staining and Western blotting were used to elucidate the related protein expression. Finally, mice were injected the Nrf-2 inhibitor ML385 to reversely verify the effects of YXFMs. RESULTS In our in vivo experiments, YXFMs significantly inhibited aging-induced SSS, shortened the R-R interval, increased heart rate, alleviated fibrosis, reduced apoptosis rate and ROS content, and promote HCN4 expression in the SAN. In our in vitro experiments, YXFMs significantly inhibited H2O2-induced cell peroxidation damage, promoted Nrf-2 activation and nuclear metastasis, increased HO-1 expression- thereby inhibiting ROS accumulation-and finally, upregulated HCN4 expression through the inhibition of histone deacetylase 4 (HDAC4) expression and its nuclear metastasis. Finally, injection of the Nrf-2 inhibitor ML385 after YXFMs administration inhibited their protective effect in the mice. CONCLUSION Here, we elaborated on the relationship between aging-induced SSS and the Nrf-2/HO-1 pathway for the first time and proposed that YXFMs improve SSS via the Nrf-2/HO-1 axis. Specifically, YXFMs promoted Nrf-2 activation and plasma-nuclear transfer to enhance HO-1 expression via the Nrf-2/HO-1 axis. This inhibited OS and reduced ROS accumulation in the SAN, and then, through the ROS/HDAC4 axis, reduced HDAC4 expression and plasma-nuclear transfer. Thereby, the OS-induced HCN4 loss in the SAN was inhibited-improving the function of If channel and thus producing SAN protection effect against SSS and improving the heart rate and R-R interval. In the future, we plan to use bioinformatics analysis technology to execute the next step of our research, namely to determine the effect of isolated, purified components of YXFMs in SSS, to increase its efficiency and reduce the toxicity of YXFMs.
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Affiliation(s)
- Heng Zhang
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Lingkang Li
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Miao Hao
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Keyan Chen
- Department of Laboratory Animal Science, China Medical University, Shenyang, 110000, China
| | - Yongping Lu
- Department of NHC Key Laboratory of Reproductive Health and Medical Genetics, Liaoning Research Institute of Family Planning (The Affiliated Reproductive Hospital of China Medical University), Shenyang, 110000, China
| | - Jing Qi
- Department of Cardiology, Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Wei Chen
- Department of Cardiology, Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Lu Ren
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China; Department of Cardiology, Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Xintong Cai
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Chen Chen
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Zhuang Liu
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Bin Zhao
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Zhishuang Li
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China
| | - Ping Hou
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China; Department of Cardiology, Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang, 110000, China.
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13
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Saponaro A, Bauer D, Giese MH, Swuec P, Porro A, Gasparri F, Sharifzadeh AS, Chaves-Sanjuan A, Alberio L, Parisi G, Cerutti G, Clarke OB, Hamacher K, Colecraft HM, Mancia F, Hendrickson WA, Siegelbaum SA, DiFrancesco D, Bolognesi M, Thiel G, Santoro B, Moroni A. Gating movements and ion permeation in HCN4 pacemaker channels. Mol Cell 2021; 81:2929-2943.e6. [PMID: 34166608 PMCID: PMC8294335 DOI: 10.1016/j.molcel.2021.05.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/12/2021] [Accepted: 05/27/2021] [Indexed: 10/31/2022]
Abstract
The HCN1-4 channel family is responsible for the hyperpolarization-activated cation current If/Ih that controls automaticity in cardiac and neuronal pacemaker cells. We present cryoelectron microscopy (cryo-EM) structures of HCN4 in the presence or absence of bound cAMP, displaying the pore domain in closed and open conformations. Analysis of cAMP-bound and -unbound structures sheds light on how ligand-induced transitions in the channel cytosolic portion mediate the effect of cAMP on channel gating and highlights the regulatory role of a Mg2+ coordination site formed between the C-linker and the S4-S5 linker. Comparison of open/closed pore states shows that the cytosolic gate opens through concerted movements of the S5 and S6 transmembrane helices. Furthermore, in combination with molecular dynamics analyses, the open pore structures provide insights into the mechanisms of K+/Na+ permeation. Our results contribute mechanistic understanding on HCN channel gating, cyclic nucleotide-dependent modulation, and ion permeation.
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Affiliation(s)
- Andrea Saponaro
- Department of Biosciences, University of Milan, Milan, Italy
| | - Daniel Bauer
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - M Hunter Giese
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Paolo Swuec
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | | | | | | | - Antonio Chaves-Sanjuan
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | - Laura Alberio
- Department of Biosciences, University of Milan, Milan, Italy; Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giacomo Parisi
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Gabriele Cerutti
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Kay Hamacher
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Wayne A Hendrickson
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Steven A Siegelbaum
- Department of Neuroscience, Zuckerman Institute, Columbia University, New York, NY, USA
| | - Dario DiFrancesco
- Department of Biosciences, University of Milan, Milan, Italy; Institute of Biophysics-Milano, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | - Gerhard Thiel
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - Bina Santoro
- Department of Neuroscience, Zuckerman Institute, Columbia University, New York, NY, USA.
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy; Institute of Biophysics-Milano, Consiglio Nazionale delle Ricerche, Rome, Italy.
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14
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Benzoni P, Nava L, Giannetti F, Guerini G, Gualdoni A, Bazzini C, Milanesi R, Bucchi A, Baruscotti M, Barbuti A. Dual role of miR-1 in the development and function of sinoatrial cells. J Mol Cell Cardiol 2021; 157:104-12. [PMID: 33964276 DOI: 10.1016/j.yjmcc.2021.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 11/20/2022]
Abstract
miR-1, the most abundant miRNA in the heart, modulates expression of several transcription factors and ion channels. Conditions affecting the heart rate, such as endurance training and cardiac diseases, show a concomitant miR-1 up- or down-regulation. Here, we investigated the role of miR-1 overexpression in the development and function of sinoatrial (SAN) cells using murine embryonic stem cells (mESC). We generated mESCs either overexpressing miR-1 and EGFP (miR1OE) or EGFP only (EM). SAN-like cells were selected from differentiating mESC using the CD166 marker. Gene expression and electrophysiological analysis were carried out on both early mES-derived cardiac progenitors and SAN-like cells and on beating neonatal rat ventricular cardiomyocytes (NRVC) over-expressing miR-1. miR1OE cells increased significantly the proportion of CD166+ SAN precursors compared to EM cells (23% vs 12%) and the levels of the transcription factors TBX5 and TBX18, both involved in SAN development. miR1OE SAN-like cells were bradycardic (1,3 vs 2 Hz) compared to EM cells. In agreement with data on native SAN cells, EM SAN-like cardiomyocytes show two populations of cells expressing either slow- or fast-activating If currents; miR1OE SAN-like cells instead have only fast-activating If with a significantly reduced conductance. Western Blot and immunofluorescence analysis showed a reduced HCN4 signal in miR-1OE vs EM CD166+ precursors. Together these data point out to a specific down-regulation of the slow-activating HCN4 subunit by miR-1. Importantly, the rate and If alterations were independent of the developmental effects of miR-1, being similar in NRVC transiently overexpressing miR-1. In conclusion, we demonstrated a dual role of miR-1, during development it controls the proper development of sinoatrial-precursor, while in mature SAN-like cells it modulates the HCN4 pacemaker channel translation and thus the beating rate.
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15
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Scridon A, Halaţiu VB, Balan AI, Cozac DA, Moldovan V, Bănescu C, Perian M, Şerban RC. Long-Term Effects of Ivabradine on Cardiac Vagal Parasympathetic Function in Normal Rats. Front Pharmacol 2021; 12:596956. [PMID: 33897414 PMCID: PMC8061748 DOI: 10.3389/fphar.2021.596956] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/26/2021] [Indexed: 01/08/2023] Open
Abstract
Background: The complex interactions that exist between the pacemaker current, I f, and the parasympathetic nervous system could significantly influence the course of patients undergoing chronic therapy with the I f blocker ivabradine. We thus aimed to assess the effects of chronic ivabradine therapy on autonomic modulation and on the cardiovascular response to in situ and in vitro parasympathetic stimulation. The right atrial expression of HCN genes, encoding proteins for I f, was also evaluated. Methods: Sympathetic and parasympathetic heart rate variability parameters and right atrial HCN(1-4) RNA levels were analyzed in 6 Control and 10 ivabradine-treated male Wistar rats (IVA; 3 weeks, 10 mg/kg/day). The heart rate (HR) and systolic blood pressure (SBP) responses to in situ electrical stimulation of the vagus nerve (2-20 Hz) were assessed in 6 additional Control and 10 IVA rats. The spontaneous sinus node discharge rate (SNDR) response to in vitro cholinergic receptors stimulation using carbamylcholine (10-9-10-6 mol/L) was also assessed in these later rats. Results: Ivabradine significantly increased vagal modulation and shifted the sympatho-vagal balance toward vagal dominance. In Control, in situ vagus nerve stimulation induced progressive decrease in both the SBP (p = 0.0001) and the HR (p< 0.0001). Meanwhile, in IVA, vagal stimulation had no effect on the HR (p = 0.16) and induced a significantly lower drop in SBP (p< 0.05). IVA also displayed a significantly lower SNDR drop in response to carbamylcholine (p< 0.01) and significantly higher right atrial HCN4 expression (p = 0.02). Conclusion: Chronic ivabradine administration enhanced vagal modulation in healthy rats. In addition, ivabradine reduced the HR response to direct muscarinic receptors stimulation, canceled the cardioinhibitory response and blunted the hemodynamic response to in situ vagal stimulation. These data bring new insights into the mechanisms of ivabradine-related atrial proarrhythmia and suggest that long-term I f blockade may protect against excessive bradycardia induced by acute vagal activation.
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Affiliation(s)
- Alina Scridon
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania.,Center for Advanced Medical and Pharmaceutical Research, Târgu Mureş, Romania
| | - Vasile Bogdan Halaţiu
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania
| | - Alkora Ioana Balan
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania
| | - Dan Alexandru Cozac
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania.,Emergency Institute for Cardiovascular Diseases and Transplantation Târgu Mureş, Târgu Mureş, Romania
| | - Valeriu Moldovan
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania.,Center for Advanced Medical and Pharmaceutical Research, Târgu Mureş, Romania
| | - Claudia Bănescu
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania.,Center for Advanced Medical and Pharmaceutical Research, Târgu Mureş, Romania
| | - Marcel Perian
- University of Medicine, Pharmacy, Science and Technology "George Emil Palade" of Târgu Mureş, Târgu Mureş, Romania.,Center for Advanced Medical and Pharmaceutical Research, Târgu Mureş, Romania
| | - Răzvan Constantin Şerban
- Emergency Institute for Cardiovascular Diseases and Transplantation Târgu Mureş, Târgu Mureş, Romania
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16
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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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Fujii K, Nakajo K, Egashira Y, Yamamoto Y, Kitada K, Taniguchi K, Kawai M, Tomiyama H, Kawakami K, Uchiyama K, Ono F. Gastrointestinal Neurons Expressing HCN4 Regulate Retrograde Peristalsis. Cell Rep 2021; 30:2879-2888.e3. [PMID: 32130893 DOI: 10.1016/j.celrep.2020.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/30/2019] [Accepted: 02/06/2020] [Indexed: 12/31/2022] Open
Abstract
Peristalsis is indispensable for physiological function of the gut. The enteric nervous system (ENS) plays an important role in regulating peristalsis. While the neural network regulating anterograde peristalsis, which migrates from the oral end to the anal end, is characterized to some extent, retrograde peristalsis remains unresolved with regards to its neural regulation. Using forward genetics in zebrafish, we reveal that a population of neurons expressing a hyperpolarization-activated nucleotide-gated channel HCN4 specifically regulates retrograde peristalsis. When HCN4 channels are blocked by an HCN channel inhibitor or morpholinos blocking the protein expression, retrograde peristalsis is specifically attenuated. Conversely, when HCN4(+) neurons expressing channelrhodopsin are activated by illumination, retrograde peristalsis is enhanced while anterograde peristalsis remains unchanged. We propose that HCN4(+) neurons in the ENS forward activating signals toward the oral end and simultaneously stimulate local circuits regulating the circular muscle.
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Affiliation(s)
- Kensuke Fujii
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Koichi Nakajo
- Department of Physiology, Osaka Medical College, Takatsuki, Japan; Division of Integrative Physiology, Department of Physiology, Jichi Medical University, Shimotsuke, Japan
| | | | | | - Kazuya Kitada
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Kohei Taniguchi
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Masaru Kawai
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Hideki Tomiyama
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics and Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan
| | - Kazuhisa Uchiyama
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Japan
| | - Fumihito Ono
- Department of Physiology, Osaka Medical College, Takatsuki, Japan.
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18
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Soattin L, Borbas Z, Caldwell J, Prendergast B, Vohra A, Saeed Y, Hoschtitzky A, Yanni J, Atkinson A, Logantha SJ, Borbas B, Garratt C, Morris GM, Dobrzynski H. Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease. Front Physiol 2021; 12:592229. [PMID: 33746765 PMCID: PMC7969524 DOI: 10.3389/fphys.2021.592229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/18/2021] [Indexed: 12/19/2022] Open
Abstract
Background The sinoatrial/sinus node (SAN) is the primary pacemaker of the heart. In humans, SAN is surrounded by the paranodal area (PNA). Although the PNA function remains debated, it is thought to act as a subsidiary atrial pacemaker (SAP) tissue and become the dominant pacemaker in the setting of sinus node disease (SND). Large animal models of SND allow characterization of SAP, which might be a target for novel treatment strategies for SAN diseases. Methods A goat model of SND was developed (n = 10) by epicardially ablating the SAN and validated by mapping of emergent SAP locations through an ablation catheter and surface electrocardiogram (ECG). Structural characterization of the goat SAN and SAP was assessed by histology and immunofluorescence techniques. Results When the SAN was ablated, SAPs featured a shortened atrioventricular conduction, consistent with the location in proximity of atrioventricular junction. SAP recovery time showed significant prolongation compared to the SAN recovery time, followed by a decrease over a follow-up of 4 weeks. Like the SAN tissue, the SAP expressed the main isoform of pacemaker hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) and Na+/Ca2+ exchanger 1 (NCX1) and no high conductance connexin 43 (Cx43). Structural characterization of the right atrium (RA) revealed that the SAN was located at the earliest activation [i.e., at the junction of the superior vena cava (SVC) with the RA] and was surrounded by the paranodal-like tissue, extending down to the inferior vena cava (IVC). Emerged SAPs were localized close to the IVC and within the thick band of the atrial muscle known as the crista terminalis (CT). Conclusions SAN ablation resulted in the generation of chronic SAP activity in 60% of treated animals. SAP displayed development over time and was located within the previously discovered PNA in humans, suggesting its role as dominant pacemaker in SND. Therefore, SAP in goat constitutes a promising stable target for electrophysiological modification to construct a fully functioning pacemaker.
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Affiliation(s)
- Luca Soattin
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Zoltan Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
| | - Jane Caldwell
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Hull University Teaching Hospitals, Hull, United Kingdom.,Hull York Medical School, Hull, United Kingdom
| | - Brian Prendergast
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Akbar Vohra
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Yawer Saeed
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Department of Medicine, Aga Khan University, Karachi, Pakistan
| | - Andreas Hoschtitzky
- Adult Congenital Heart Disease Unit, Manchester Royal Infirmary, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Royal Brompton Hospital, London, United Kingdom.,Imperial College London, London, United Kingdom
| | - Joseph Yanni
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew Atkinson
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Sunil Jit Logantha
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Sciences, Department of Cardiovascular and Metabolic Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Balint Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Clifford Garratt
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Gwilym Matthew Morris
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Department of Anatomy, Jagiellonian University, Krakow, Poland
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19
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Han ZL, Wu X, Liu XH, Chen Z, Bai J, Chen X, Xu W. [The effects of PDK1-Akt signaling pathway intervention on cardiomyocyte HCN4 ion channels]. Zhonghua Xin Xue Guan Bing Za Zhi 2020; 48:954-961. [PMID: 33210868 DOI: 10.3760/cma.j.cn112148-20200929-00778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To explore the effects of 3-phosphate dependent protein kinase 1-protein kinase B (PDK1-Akt) signaling pathway on the transcription, expression and function of cardiac hyperpolarized activated cyclic nucleotide gated 4 (HCN4) ion channels. Methods: Atrial myocytes were obtained from healthy male wild-type C57 mice and heart-specific PDK1 knockout mice (PDK1-KO) by enzymolysis. Then the atrial myocytes were divided into blank control group and PDK1-KO group. In further studies, the isolated atrial myocytes were cultured and further divided into drug control group (treated with dimethyl sulfoxide (DMSO)) and PDK1 knockdown group (treated with 1 μg/ml PDK1 short hairpin RNA (shRNA) interference plasmid), SC79 group (treated with 8 μmol/ml SC79), GSK2334470 group (treated with 10 nmol/L GSK2334470) and PDK1 knockdown+SC79 group (8 μmol/ml SC79 and 1 μg/ml PDK1 shRNA interference plasmid). Real time quantitative PCR (qRT-PCR) was used to detect the mRNA expression levels of PDK1 and HCN4, Western blot was used to detect the protein expression levels of PDK1, Akt and HCN4, the whole cell patch clamp was used to detecte the current density of HCN, and immunofluorescence was used to detecte the expression of HCN4 protein on atrial cells. Results: (1) the expression levels of HCN4 mRNA (1.46±0.03 vs. 0.99±0.01, P<0.001) and protein (1.14±0.02 vs. 1.00±0.06, P=0.017) in PDK1-KO group were higher than those in blank control group. The HCN current density in PDK1-KO group was higher than that in blank control group((-17.47±2.00) pA/pF vs. (-12.15±2.25) pA/pF, P=0.038). (2) The functions of PDK1 shRNA and specific Akt agonist SC79 were verified by comparing the PDK1 knockdown group and SC79 group with the drug control group. The results showed that the expression levels of PDK1 mRNA and protein in PDK1 knockdown group were lower than those in drug control group, and the expression level of phosphorylated Akt (Thr 308) protein in SC79 group was higher than that in drug control group. (3) The expression levels of HCN4 mRNA (3.61±0.46 vs. 1.00±0.08, P<0.001) and protein (2.33±0.11 vs. 1.00±0.05, P<0.001) in GSK2334470 group were higher than those in drug control group. (4) To reduce the effect of drug-miss target, the cultured atrial myocytes were transfected with shRNA plasmid of PDK1 and intervened with SC79. The results showed that the expression of HCN4 mRNA in PDK1 knockdown group was higher than that in the drug control group (1.76±0.11 vs. 1.00±0.06, P<0.001), and PDK1 knockdown+SC79 group (1.76±0.11 vs. 1.33±0.07, P=0.003). In PDK1 knockdown+SC79 group, the mRNA expression level was also higher than that in the drug control group (1.33±0.07 vs. 1.00±0.06, P<0.001). The expression level of HCN4 protein in PDK1 knockdown group was higher than that in drug control group (1.15±0.04 vs. 1.00±0.05, P=0.003). As for the The expression level of HCN4 protein, there was no significantly statistical difference between the PDK1 knockdown+SC79 group and the drug control group (P>0.05), but PDK1 knockdown+SC79 group was lower than PDK1 knockdown group (0.95±0.01 vs. 1.15±0.04, P<0.001). In patch clamp experiments, the results showed that the HCN current density was (-13.27±1.28) pA/pF in the drug control group, (-18.76±2.03) pA/pF in the PDK1 knockdown group, (-13.50±2.58) pA/pF in the PDK1 knockdown+SC79 group; the HCN current density of PDK1 knockdown group was higher than that of drug control group (P<0.001), but there was no significant difference between PDK1 knockdown+SC79 group and drug control group (P>0.05). (5) The results of immunofluorescence showed that the brightness of green fluorescence of PDK1 knockdown group was higher than that of drug control group, indicating that the expression of HCN4 localized on cell membrane was increased. However, the green fluorescence of PDK1 knockdown+SC79 group was lighter than that of PDK1 knockdown group, suggesting that the expression of HCN4 in PDK1-knockdown cell membrane decreased after further activating Akt. Conclusion: PDK1-Akt signaling pathway is involved in the regulation of HCN4 ion channel transcription, expression and function.
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Affiliation(s)
- Z L Han
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - X Wu
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - X H Liu
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - Z Chen
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - J Bai
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - X Chen
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - W Xu
- Department of Cardiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
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20
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Tesoro L, Ramirez-Carracedo R, Hernandez I, Diez-Mata J, Pascual M, Saura M, Sanmartin M, Zamorano JL, Zaragoza C. Ivabradine induces cardiac protection by preventing cardiogenic shock-induced extracellular matrix degradation. ACTA ACUST UNITED AC 2020; 74:1062-1071. [PMID: 33132099 DOI: 10.1016/j.rec.2020.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 09/11/2020] [Indexed: 02/07/2023]
Abstract
INTRODUCTION AND OBJECTIVES Ivabradine reduces heart rate by blocking the I(f) current and preserves blood pressure and stroke volume through unknown mechanisms. Caveolin-3 protects the heart by forming protein complexes with several proteins, including extracellular matrix (ECM)-metalloproteinase-inducer (EMMPRIN) and hyperpolarization-activated cyclic nucleotide-gated channel 4 (HN4), a target of ivabradine. We hypothesized that ivabradine might also exert cardioprotective effects through inhibition of ECM degradation. METHODS In a porcine model of cardiogenic shock, we studied the effects of ivabradine on heart integrity, the levels of MMP-9 and EMMPRIN, and the stability of caveolin-3/HCN4 protein complexes with EMMPRIN. RESULTS Administration of 0.3 mg/kg ivabradine significantly reduced cardiogenic shock-induced ventricular necrosis and expression of MMP-9 without affecting EMMPRIN mRNA, protein, or protein glycosylation (required for MMP activation). However, ivabradine increased the levels of the caveolin-3/LG-EMMPRIN (low-glycosylated EMMPRIN) and caveolin-3/HCN4 protein complexes and decreased that of a new complex between HCN4 and high-glycosylated EMMPRIN formed in response to cardiogenic shock. We next tested whether caveolin-3 can bind to HCN4 and EMMPRIN and found that the HCN4/EMMPRIN complex was preserved when we silenced caveolin-3 expression, indicating a direct interaction between these 2 proteins. Similarly, EMMPRIN-silenced cells showed a significant reduction in the binding of caveolin-3/HCN4, which regulates the I(f) current, suggesting that, rather than a direct interaction, both proteins bind to EMMPRIN. CONCLUSIONS In addition to inhibition of the I(f) current, ivabradine may induce cardiac protection by inhibiting ECM degradation through preservation of the caveolin-3/LG-EMMPRIN complex and control heart rate by stabilizing the caveolin-3/HCN4 complex.
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Affiliation(s)
- Laura Tesoro
- Unidad de Investigación Cardiovascular, Departamento de Cardiología, Universidad Francisco de Vitoria, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain; Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | | | - Ignacio Hernandez
- Unidad de Investigación Cardiovascular, Departamento de Cardiología, Universidad Francisco de Vitoria, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain; Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Javier Diez-Mata
- Unidad de Investigación Cardiovascular, Departamento de Cardiología, Universidad Francisco de Vitoria, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain; Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Marina Pascual
- Departamento de Cardiología, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain
| | - Marta Saura
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Unidad de Fisiología, Departamento de Biología de Sistemas, Universidad de Alcalá (IRYCIS). Alcalá de Henares, Madrid, Spain
| | - Marcelo Sanmartin
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain
| | - José Luis Zamorano
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Cardiología, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain
| | - Carlos Zaragoza
- Unidad de Investigación Cardiovascular, Departamento de Cardiología, Universidad Francisco de Vitoria, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain; Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), Spain.
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21
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Alonso-Fernández-Gatta M, Gallego-Delgado M, Caballero R, Villacorta E, Díaz-Peláez E, García-BerrocaL B, Crespo-García T, Plata-Izquierdo B, Marcos-Vadillo E, García-Cuenllas L, Barreiro-Pérez M, Isidoro-García M, Tamargo-Menéndez J, Delpón E, Sánchez PL. A rare HCN4 variant with combined sinus bradycardia, left atrial dilatation, and hypertrabeculation/left ventricular noncompaction phenotype. ACTA ACUST UNITED AC 2020; 74:781-789. [PMID: 33008772 DOI: 10.1016/j.rec.2020.06.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/24/2020] [Indexed: 01/20/2023]
Abstract
INTRODUCTION AND OBJECTIVES HCN4 variants have been reported to cause combined sick sinus syndrome (SSS) and left ventricular noncompaction (LVNC) cardiomyopathy. This relationship has been proven in few cases and no previous patients have associated left atrial dilatation (LAD). Our objective was to study a familial disorder characterized by SSS, LAD, and hypertrabeculation/LVNC and to identify the underlying genetic and electrophysiological characteristics. METHODS A family with SSS and LVNC underwent a clinical, genetic, and electrophysiological assessment. They were studied via electrocardiography, Holter recording, echocardiography, and exercise stress tests; cardiac magnetic resonance imaging was additionally performed in affected individuals. Genetic testing was undertaken with targeted next-generation sequencing, as well as a functional study of the candidate variant in Chinese hamster ovary cells. RESULTS Twelve members of the family had sinus bradycardia, associated with complete criteria of LVNC in 4 members and hypertrabeculation in 6 others, as well as LAD in 9 members. A HCN4 c.1123C>T;(p.R375C) variant was present in heterozygosis in all affected patients and absent in unaffected individuals. Electrophysiological analyses showed that the amplitude and densities of the HCN4 currents (IHCN4) generated by mutant p.R375C HCN4 channels were significantly lower than those generated by wild-type channels. CONCLUSIONS The combined phenotype of SSS, LAD, and LVNC is associated with the heritable HCN4 c.1123C>T;(p.R375C) variant. HCN4 variants should be included in the genetic diagnosis of LVNC cardiomyopathy and of patients with familial forms of SSS, as well as of individuals with sinus bradycardia and LAD.
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Affiliation(s)
- Marta Alonso-Fernández-Gatta
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - María Gallego-Delgado
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain
| | - Ricardo Caballero
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Eduardo Villacorta
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain.
| | - Elena Díaz-Peláez
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain
| | - Belén García-BerrocaL
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain; Unidad de Genética, Servicio de Bioquímica, Complejo Asistencial Universitario de Salamanca. Universidad de Salamanca, Salamanca, Spain
| | - Teresa Crespo-García
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Beatriz Plata-Izquierdo
- Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain; Servicio de Pediatría, Complejo Asistencial Universitario de Salamanca, Salamanca, Spain
| | - Elena Marcos-Vadillo
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain; Unidad de Genética, Servicio de Bioquímica, Complejo Asistencial Universitario de Salamanca. Universidad de Salamanca, Salamanca, Spain
| | - Luisa García-Cuenllas
- Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain; Servicio de Pediatría, Complejo Asistencial Universitario de Salamanca, Salamanca, Spain
| | - Manuel Barreiro-Pérez
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - María Isidoro-García
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain; Unidad de Genética, Servicio de Bioquímica, Complejo Asistencial Universitario de Salamanca. Universidad de Salamanca, Salamanca, Spain
| | - Juan Tamargo-Menéndez
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Eva Delpón
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Pedro L Sánchez
- Servicio de Cardiología, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca, Salamanca, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain; Centro de Referencia Nacional de Cardiopatías Familiares (CSUR), Salamanca, Spain
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Wacker-Gussmann A, Oberhoffer-Fritz R, Westphal DS, Hessling G, Wakai RT, Strasburger JF. The missense variant p.(Gly482Arg) in HCN4 is responsible for fetal tachy-bradycardia syndrome. HeartRhythm Case Rep 2020; 6:352-356. [PMID: 32577394 PMCID: PMC7300329 DOI: 10.1016/j.hrcr.2020.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Annette Wacker-Gussmann
- Institute of Preventive Pediatrics, Technical University of Munich, and Department of Pediatric Cardiology and Adult Congenital Heart Disease Munich, German Heart Center Munich, Munich, Germany
| | - Renate Oberhoffer-Fritz
- Institute of Preventive Pediatrics, Technical University of Munich, and Department of Pediatric Cardiology and Adult Congenital Heart Disease Munich, German Heart Center Munich, Munich, Germany
| | - Dominik S Westphal
- Institute of Human Genetics, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Gabriele Hessling
- Department of Electrophysiology, German Heart Center Munich, Munich, Germany
| | - Ronald T Wakai
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Janette F Strasburger
- Department of Pediatrics, Division of Cardiology Herma Heart Institute, Children's Wisconsin, Milwaukee, Wisconsin
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Li XH, Hu YM, Yin GL, Wu P. Correlation between HCN4 gene polymorphisms and lone atrial fibrillation risk. Artif Cells Nanomed Biotechnol 2019; 47:2989-2993. [PMID: 31315459 DOI: 10.1080/21691401.2019.1637885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Background and objective: Atrial electrical remodelling (AER) was significantly associated with atrial fibrillation (AF) development. Polymorphisms in hyperpolarization activated cyclic nucleotide gated potassium channel 4 (HCN4) gene might be correlated with AER. In the present study, we explored the association of HCN4 polymorphisms (rs498005 and rs7164883) with lone AF risk in a Chinese Han population. Methods: In this case-control study, the Sanger sequencing method was utilized to genotype the HCN4 polymorphisms. Relative risk of AF was assessed by the χ2 test, and presented by odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Logistic regression analysis was performed for multivariate analysis. The effects of HCN4 polymorphisms on AF clinical features were analyzed by the Mann-Whitney U test and adjusted by the Bonferroni method. Results: C allele of rs498005 was significantly correlated with increased risk of AF (OR = 1.412, 95%CI = 1.012-1.970), and the association still exited after adjustment by age, gender, the status of smoking and drinking, histories of diabetes, hyperlipidaemia and myocardial infarction (adjusted OR = 1.473, 95%CI = 1.043-2.081). G allele of rs7164883 SNP was marginally associated with enhanced AF risk after adjustment by the above clinical parameters (adjusted OR = 1.742, 95%CI = 1.019-2.980). Atrial late potential (ALP), including TP (P wave duration after filtering) and LP20 (the amplitude of superimposed potential in the final 20 ms of P wave) were significantly associated with rs498005 genotype (p < .001). Conclusion: HCN4 rs498005 and rs7164883 polymorphisms are significantly associated with AF risk.
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Affiliation(s)
- Xiao-Hong Li
- a Department of Cardiology, Cangzhou City Central Hospital , Cangzhou , China
| | - Ya-Min Hu
- a Department of Cardiology, Cangzhou City Central Hospital , Cangzhou , China
| | - Guang-Li Yin
- b Department of Cardiology, Hebei Provincial Hospital of Integrative Chinese and Western Medicine , Cangzhou , China
| | - Ping Wu
- a Department of Cardiology, Cangzhou City Central Hospital , Cangzhou , China
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24
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Dong J, Subbotina E, Williams N, Sampson BA, Tang Y, Coetzee WA. Functional reclassification of variants of uncertain significance in the HCN4 gene identified in sudden unexpected death. Pacing Clin Electrophysiol 2019; 42:275-282. [PMID: 30578647 DOI: 10.1111/pace.13593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/07/2018] [Accepted: 12/18/2018] [Indexed: 11/28/2022]
Abstract
The HCN4 gene encodes a subunit of the hyperpolarization-activated cyclic nucleotide-gated channel, type 4 that is essential for the proper generation of pacemaker potentials in the sinoatrial node. The HCN4 gene is often present in targeted genetic testing panels for various cardiac conduction system disorders and there are several reports of HCN4 variants associated with conduction disorders. Here, we report the in vitro functional characterization of four rare variants of uncertain significance (VUS) in HCN4, identified through testing a cohort of 296 sudden unexpected natural deaths. The variants are all missense alterations, leading to single amino acid changes: p.E66Q in the N-terminus, p.D546N in the C-linker domain, and both p.S935Y and p.R1044Q in the C-terminus distal to the CNBD. We also identified a likely benign variant, p. P1063T, which has a high minor allele frequency in the gnomAD, which is utilized here as a negative control. Three of the HCN4 VUS (p.E66Q, p.S935Y, and p.R1044Q) had electrophysiological characteristics similar to the wild-type channel, suggesting that these variants are benign. In contrast, the p.D546N variant in the C-linker domain exhibited a larger current density, slower activation, and was unresponsive to cyclic adenosine monophosphate (cAMP) compared to wild-type. With functional assays, we reclassified three rare HCN4 VUS to likely benign variants, eliminating the necessity for costly and time-consuming further study. Our studies also provide a new lead to investigate how a VUS located in the C-linker connecting the pore to the cAMP binding domain may affect the channel open state probability and cAMP response.
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Affiliation(s)
- Jingyun Dong
- Departments of Pediatrics, NYU School of Medicine, New York, New York
| | | | - Nori Williams
- Molecular Genetics Laboratory, New York City Office of Chief Medical Examiner, New York, New York
| | - Barbara A Sampson
- Department of Forensic Pathology, New York City Office of Chief Medical Examiner, New York, New York
| | - Yingying Tang
- Molecular Genetics Laboratory, New York City Office of Chief Medical Examiner, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, NYU School of Medicine, New York, New York.,Departments of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York.,Departments of Physiology and Neurosciences, NYU School of Medicine, New York, New York
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25
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Xiao H, Yang YJ, Lin YZ, Peng S, Lin S, Song ZY. Transcription factor Tbx18 induces the differentiation of c-kit + canine mesenchymal stem cells (cMSCs) into SAN-like pacemaker cells in a co-culture model in vitro. Am J Transl Res 2018; 10:2511-2528. [PMID: 30210689 PMCID: PMC6129520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/08/2018] [Indexed: 06/08/2023]
Abstract
Bone mesenchymal stem cells (MSCs), as well as cardiomyocytes, are derived from early mesoderm, becoming committed to their fate under the influence of different differentiation factors. We examined whether the overexpression of Tbx18 can induce the differentiation of c-kit+ cMSCs into a phenotype similar to that of native pacemaker cells and whether these transfected cells can couple to adjacent atrial cells with functional consequences. The c-kit+ cMSCs were first sorted, then transfected with different lentiviral vectors. Tbx18-c-kit+ cMSCs represented the experimental group, while EYFP-c-kit+ cMSCs and canine sinoatrial node (SAN) cells were used as controls. Within days of transfection, the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel HCN4 protein and gap junction protein Connexin 45 (Cx45) expression in Tbx18-c-kit+ cMSCs were 12-fold and 5.6-fold higher, respectively, than that in EYFP-c-kit+ cMSCs. After co-culture with canine atrial cells in vitro for three days, the funny currents (If) were recorded in the Tbx18-c-kit+ cMSCs, but not in EYFP-c-kit+ cMSCs. The trend of these If currents was highly similar to that of SAN cells, although the current density was smaller. The Tbx18-EYFP-c-kit+ cMSCs showed responsiveness to β-adrenergic stimulation, and the intracellular cyclic adenosine monophosphate (cAMP) level was higher than that in EYFP-c-kit+ cMSCs. The Tbx18-EYFP-c-kit+ cMSCs delivered fluorescent dye to neighboring atrial cells via gap junctions, thus these cell pairs could communicate as a pacemaker unit. We propose that the overexpression of Tbx18 in c-kit+ cMSCs induces their differentiation to SAN-like pacemaker cells.
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Affiliation(s)
- Hua Xiao
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
- Department of Cardiology, The 452 Hospital of PLAChengdu 610000, Sichuan, P.R. China
| | - Yong-Jun Yang
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
| | - Yi-Zhang Lin
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
| | - Song Peng
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
| | - Shu Lin
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
- School of Medicine, University of Wollongong and Illawarra Health and Medical Research InstituteNSW 2522, Australia
| | - Zhi-Yuan Song
- Department of Cardiology, Southwest Hospital, Third Military Medical University (Army Medical University)Chongqing 400038, P.R. China
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26
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Campostrini G, DiFrancesco JC, Castellotti B, Milanesi R, Gnecchi-Ruscone T, Bonzanni M, Bucchi A, Baruscotti M, Ferrarese C, Franceschetti S, Canafoglia L, Ragona F, Freri E, Labate A, Gambardella A, Costa C, Gellera C, Granata T, Barbuti A, DiFrancesco D. A Loss-of-Function HCN4 Mutation Associated With Familial Benign Myoclonic Epilepsy in Infancy Causes Increased Neuronal Excitability. Front Mol Neurosci 2018; 11:269. [PMID: 30127718 PMCID: PMC6089338 DOI: 10.3389/fnmol.2018.00269] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/16/2018] [Indexed: 01/03/2023] Open
Abstract
HCN channels are highly expressed and functionally relevant in neurons and increasing evidence demonstrates their involvement in the etiology of human epilepsies. Among HCN isoforms, HCN4 is important in cardiac tissue, where it underlies pacemaker activity. Despite being expressed also in deep structures of the brain, mutations of this channel functionally shown to be associated with epilepsy have not been reported yet. Using Next Generation Sequencing for the screening of patients with idiopathic epilepsy, we identified the p.Arg550Cys (c.1648C>T) heterozygous mutation on HCN4 in two brothers affected by benign myoclonic epilepsy of infancy. Functional characterization in heterologous expression system and in neurons showed that the mutation determines a loss of function of HCN4 contribution to activity and an increase of neuronal discharge, potentially predisposing to epilepsy. Expressed in cardiomyocytes, mutant channels activate at slightly more negative voltages than wild-type (WT), in accordance with borderline bradycardia. While HCN4 variants have been frequently associated with cardiac arrhythmias, these data represent the first experimental evidence that functional alteration of HCN4 can also be involved in human epilepsy through a loss-of-function effect and associated increased neuronal excitability. Since HCN4 appears to be highly expressed in deep brain structures only early during development, our data provide a potential explanation for a link between dysfunctional HCN4 and infantile epilepsy. These findings suggest that it may be useful to include HCN4 screening to extend the knowledge of the genetic causes of infantile epilepsies, potentially paving the way for the identification of innovative therapeutic strategies.
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Affiliation(s)
- Giulia Campostrini
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Jacopo C DiFrancesco
- Clinical Neurophysiology and Epilepsy Center, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Laboratory of Neurobiology, Department of Neurology, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Raffaella Milanesi
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | | | - Mattia Bonzanni
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Annalisa Bucchi
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Mirko Baruscotti
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Carlo Ferrarese
- Laboratory of Neurobiology, Department of Neurology, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Silvana Franceschetti
- Clinical Neurophysiology and Epilepsy Center, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Laura Canafoglia
- Clinical Neurophysiology and Epilepsy Center, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Angelo Labate
- Institute of Neurology, Università degli Studi Magna Græcia di Catanzaro, Catanzaro, Italy
| | - Antonio Gambardella
- Institute of Neurology, Università degli Studi Magna Græcia di Catanzaro, Catanzaro, Italy
| | - Cinzia Costa
- Neurology Unit, Ospedale S. Maria della Misericordia, Department of Medicine, University of Perugia, Perugia, Italy
| | - Cinzia Gellera
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Andrea Barbuti
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Dario DiFrancesco
- Molecular Physiology and Neurobiology, The PaceLab, Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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27
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Abstract
The hyperpolarization-activated cyclic-nucleotide-modulated (HCN) proteins are cAMP-regulated ion channels that play a key role in nerve impulse transmission and heart rate modulation in neuronal and cardiac cells, respectively. Although they are regulated primarily by cAMP, other cyclic nucleotides such as cGMP, cCMP, and cUMP serve as partial agonists for the HCN2 and HCN4 isoforms. By competing with cAMP for binding, these non-canonical ligands alter ion channel gating, and in turn, modulate the cAMP-dependent activation profiles. The partial activation of non-canonical cyclic nucleotides can be rationalized by either a partial reversal of a two-state inactive/active conformational equilibrium, or by sampling of a third conformational state with partial activity. Furthermore, different mechanisms and degrees of activation have been observed upon binding of non-canonical cyclic nucleotides to HCN2 versus HCN4, suggesting that these ligands control HCN ion channels in an isoform-specific manner. While more work remains to be done to achieve a complete understanding of ion channel modulation by non-canonical cyclic nucleotides, it is already clear that such knowledge will ultimately prove invaluable in achieving a more complete understanding of ion channel signaling in vivo, as well as in the development of therapeutics designed to selectively modulate ion channel gating.
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Affiliation(s)
- Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4M1
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4M1. .,Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4M1.
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28
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Pai VP, Willocq V, Pitcairn EJ, Lemire JM, Paré JF, Shi NQ, McLaughlin KA, Levin M. HCN4 ion channel function is required for early events that regulate anatomical left-right patterning in a nodal and lefty asymmetric gene expression-independent manner. Biol Open 2017; 6:1445-1457. [PMID: 28818840 PMCID: PMC5665463 DOI: 10.1242/bio.025957] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/12/2017] [Indexed: 12/13/2022] Open
Abstract
Laterality is a basic characteristic of all life forms, from single cell organisms to complex plants and animals. For many metazoans, consistent left-right asymmetric patterning is essential for the correct anatomy of internal organs, such as the heart, gut, and brain; disruption of left-right asymmetry patterning leads to an important class of birth defects in human patients. Laterality functions across multiple scales, where early embryonic, subcellular and chiral cytoskeletal events are coupled with asymmetric amplification mechanisms and gene regulatory networks leading to asymmetric physical forces that ultimately result in distinct left and right anatomical organ patterning. Recent studies have suggested the existence of multiple parallel pathways regulating organ asymmetry. Here, we show that an isoform of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of ion channels (hyperpolarization-activated cyclic nucleotide-gated channel 4, HCN4) is important for correct left-right patterning. HCN4 channels are present very early in Xenopus embryos. Blocking HCN channels (Ih currents) with pharmacological inhibitors leads to errors in organ situs. This effect is only seen when HCN4 channels are blocked early (pre-stage 10) and not by a later block (post-stage 10). Injections of HCN4-DN (dominant-negative) mRNA induce left-right defects only when injected in both blastomeres no later than the 2-cell stage. Analysis of key asymmetric genes' expression showed that the sidedness of Nodal, Lefty, and Pitx2 expression is largely unchanged by HCN4 blockade, despite the randomization of subsequent organ situs, although the area of Pitx2 expression was significantly reduced. Together these data identify a novel, developmental role for HCN4 channels and reveal a new Nodal-Lefty-Pitx2 asymmetric gene expression-independent mechanism upstream of organ positioning during embryonic left-right patterning.
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Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Emily J Pitcairn
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Joan M Lemire
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Jean-François Paré
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Nian-Qing Shi
- Department of Medicine at University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Kelly A McLaughlin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
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29
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Tae HS, Smith KM, Phillips AM, Boyle KA, Li M, Forster IC, Hatch RJ, Richardson R, Hughes DI, Graham BA, Petrou S, Reid CA. Gabapentin Modulates HCN4 Channel Voltage-Dependence. Front Pharmacol 2017; 8:554. [PMID: 28871229 PMCID: PMC5566583 DOI: 10.3389/fphar.2017.00554] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/07/2017] [Indexed: 12/18/2022] Open
Abstract
Gabapentin (GBP) is widely used to treat epilepsy and neuropathic pain. There is evidence that GBP can act on hyperpolarization-activated cation (HCN) channel-mediated Ih in brain slice experiments. However, evidence showing that GBP directly modulates HCN channels is lacking. The effect of GBP was tested using two-electrode voltage clamp recordings from human HCN1, HCN2, and HCN4 channels expressed in Xenopus oocytes. Whole-cell recordings were also made from mouse spinal cord slices targeting either parvalbumin positive (PV+) or calretinin positive (CR+) inhibitory neurons. The effect of GBP on Ih was measured in each inhibitory neuron population. HCN4 expression was assessed in the spinal cord using immunohistochemistry. When applied to HCN4 channels, GBP (100 μM) caused a hyperpolarizing shift in the voltage of half activation (V1/2) thereby reducing the currents. Gabapentin had no impact on the V1/2 of HCN1 or HCN2 channels. There was a robust increase in the time to half activation for HCN4 channels with only a small increase noted for HCN1 channels. Gabapentin also caused a hyperpolarizing shift in the V1/2 of Ih measured from HCN4-expressing PV+ inhibitory neurons in the spinal dorsal horn. Gabapentin had minimal effect on Ih recorded from CR+ neurons. Consistent with this, immunohistochemical analysis revealed that the majority of CR+ inhibitory neurons do not express somatic HCN4 channels. In conclusion, GBP reduces HCN4 channel-mediated currents through a hyperpolarized shift in the V1/2. The HCN channel subtype selectivity of GBP provides a unique tool for investigating HCN4 channel function in the central nervous system. The HCN4 channel is a candidate molecular target for the acute analgesic and anticonvulsant actions of GBP.
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Affiliation(s)
- Han-Shen Tae
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Kelly M Smith
- School of Biomedical Sciences and Pharmacy, University of Newcastle, CallaghanNSW, Australia.,Hunter Medical Research Institute, New Lambton HeightsNSW, Australia
| | - A Marie Phillips
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia.,School of BioSciences, The University of Melbourne, ParkvilleVIC, Australia
| | - Kieran A Boyle
- Institute of Neuroscience and Psychology, University of GlasgowGlasgow, United Kingdom
| | - Melody Li
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Ian C Forster
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Robert J Hatch
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Robert Richardson
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - David I Hughes
- Institute of Neuroscience and Psychology, University of GlasgowGlasgow, United Kingdom
| | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, University of Newcastle, CallaghanNSW, Australia.,Hunter Medical Research Institute, New Lambton HeightsNSW, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
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30
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Becker F, Reid CA, Hallmann K, Tae HS, Phillips AM, Teodorescu G, Weber YG, Kleefuss-Lie A, Elger C, Perez-Reyes E, Petrou S, Kunz WS, Lerche H, Maljevic S. Functional variants in HCN4 and CACNA1H may contribute to genetic generalized epilepsy. Epilepsia Open 2017; 2:334-342. [PMID: 29588962 PMCID: PMC5862120 DOI: 10.1002/epi4.12068] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2017] [Indexed: 01/11/2023] Open
Abstract
Objective Genetic generalized epilepsy (GGE) encompasses seizure disorders characterized by spike‐and‐wave discharges (SWD) originating within thalamo‐cortical circuits. Hyperpolarization‐activated (HCN) and T‐type Ca2+ channels are key modulators of rhythmic activity in these brain regions. Here, we screened HCN4 and CACNA1H genes for potentially contributory variants and provide their functional analysis. Methods Targeted gene sequencing was performed in 20 unrelated familial cases with different subtypes of GGE, and the results confirmed in 230 ethnically matching controls. Selected variants in CACNA1H and HCN4 were functionally assessed in tsA201 cells and Xenopus laevis oocytes, respectively. Results We discovered a novel CACNA1H (p.G1158S) variant in two affected members of a single family. One of them also carried an HCN4 (p.P1117L) variant inherited from the unaffected mother. In a separate family, an HCN4 variant (p.E153G) was identified in one of several affected members. Voltage‐clamp analysis of CACNA1H (p.G1158S) revealed a small but significant gain‐of‐function, including increased current density and a depolarizing shift of steady‐state inactivation. HCN4 p.P1117L and p.G153E both caused a hyperpolarizing shift in activation and reduced current amplitudes, resulting in a loss‐of‐function. Significance Our results are consistent with a model suggesting cumulative contributions of subtle functional variations in ion channels to seizure susceptibility and GGE.
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Affiliation(s)
- Felicitas Becker
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,RKU-University Neurology Clinic of Ulm Ulm Germany
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Kerstin Hallmann
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Han-Shen Tae
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,Present address: Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong Wollongong New South Wales Australia
| | - A Marie Phillips
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia.,School of Biosciences The University of Melbourne Melbourne Victoria Australia
| | - Georgeta Teodorescu
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Yvonne G Weber
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Ailing Kleefuss-Lie
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Christian Elger
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Edward Perez-Reyes
- Department of Pharmacology University of Virginia Charlottesville Virginia U.S.A
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
| | - Wolfram S Kunz
- Department of Neurology and Epileptology University of Bonn Medical Center Bonn Germany
| | - Holger Lerche
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany
| | - Snezana Maljevic
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain-Research University of Tübingen Tübingen Germany.,The Florey Institute of Neuroscience and Mental Health Melbourne Victoria Australia
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31
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Pitcairn E, Harris H, Epiney J, Pai VP, Lemire JM, Ye B, Shi NQ, Levin M, McLaughlin KA. Coordinating heart morphogenesis: A novel role for hyperpolarization-activated cyclic nucleotide-gated (HCN) channels during cardiogenesis in Xenopus laevis. Commun Integr Biol 2017; 10:e1309488. [PMID: 28702127 PMCID: PMC5501196 DOI: 10.1080/19420889.2017.1309488] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/16/2017] [Indexed: 12/18/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide gated channel (HCN) proteins are important regulators of both neuronal and cardiac excitability. Among the 4 HCN isoforms, HCN4 is known as a pacemaker channel, because it helps control the periodicity of contractions in vertebrate hearts. Although the physiological role of HCN4 channel has been studied in adult mammalian hearts, an earlier role during embryogenesis has not been clearly established. Here, we probe the embryonic roles of HCN4 channels, providing the first characterization of the expression profile of any of the HCN isoforms during Xenopus laevis development and investigate the consequences of altering HCN4 function on embryonic pattern formation. We demonstrate that both overexpression of HCN4 and injection of dominant-negative HCN4 mRNA during early embryogenesis results in improper expression of key patterning genes and severely malformed hearts. Our results suggest that HCN4 serves to coordinate morphogenetic control factors that provide positional information during heart morphogenesis in Xenopus.
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Affiliation(s)
- Emily Pitcairn
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Hannah Harris
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Justine Epiney
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Vaibhav P Pai
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Joan M Lemire
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Bin Ye
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Nian-Qing Shi
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael Levin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Kelly A McLaughlin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
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Zhang Z, Huang TQ, Nepliouev I, Zhang H, Barnett AS, Rosenberg PB, Ou SHI, Stiber JA. Crizotinib Inhibits Hyperpolarization-activated Cyclic Nucleotide-Gated Channel 4 Activity. Cardiooncology 2017; 3. [PMID: 28217366 PMCID: PMC5310672 DOI: 10.1186/s40959-017-0020-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Sinus bradycardia is frequently observed in patients treated with crizotinib, a receptor tyrosine kinase inhibitor used for the treatment of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC). We investigated whether crizotinib could influence heart rate (HR) through direct cardiac effects. METHODS The direct effect of crizotinib on HR was studied using ECG analysis of Langendorff-perfused mouse hearts. The whole-cell patch clamp technique was used to measure the effects of crizotinib on the hyperpolarization-activated funny current, If, in mouse sinoatrial node cells (SANCs) and hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) activity in HEK-293 cells stably expressing human HCN4. RESULTS Crizotinib resulted in a dose-dependent reduction in HR in isolated intact mouse hearts with a half maximal inhibitory concentration (IC50) of 1.7 ± 0.4 μmol/L. Because ECG analysis revealed that crizotinib (0-5 μmol/L) resulted in significant reductions in HR in isolated mouse hearts without changes in PR, QRS, or QT intervals, we performed whole-cell patch clamp recordings of SANCs which showed that crizotinib inhibited If which regulates cardiac pacemaker activity. Crizotinib resulted in diminished current density of HCN4, the major molecular determinant of If, with an IC50 of 1.4 ± 0.3 μmol/L. Crizotinib also slowed HCN4 activation and shifted the activation curve to the left towards more hyperpolarized potentials. CONCLUSIONS Our results suggest that crizotinib's effects on HCN4 channels play a significant role in mediating its observed effects on HR.
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Affiliation(s)
- Zhushan Zhang
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Tai-Qin Huang
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Igor Nepliouev
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Hengtao Zhang
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Adam S Barnett
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Paul B Rosenberg
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
| | - Sai-Hong I Ou
- Department of Medicine, University of California Irvine School of Medicine, Orange, CA 92868
| | - Jonathan A Stiber
- Department of Medicine, Duke University Medical Center, Durham, NC USA 27710
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Ishikawa T, Ohno S, Murakami T, Yoshida K, Mishima H, Fukuoka T, Kimoto H, Sakamoto R, Ohkusa T, Aiba T, Nogami A, Sumitomo N, Shimizu W, Yoshiura KI, Horigome H, Horie M, Makita N. Sick sinus syndrome with HCN4 mutations shows early onset and frequent association with atrial fibrillation and left ventricular noncompaction. Heart Rhythm 2017; 14:717-724. [PMID: 28104484 DOI: 10.1016/j.hrthm.2017.01.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Indexed: 01/12/2023]
Abstract
BACKGROUND Familial sick sinus syndrome (SSS) is often attributable to mutations in genes encoding the cardiac Na channel SCN5A and pacemaker channel HCN4. We previously found that SSS with SCN5A mutations shows early onset of manifestations and male predominance. Despite recent reports on the complications of atrial fibrillation (AF) and left ventricular noncompaction (LVNC) in patients with SSS caused by HCN4 mutations, their overall clinical spectrum remains unknown. OBJECTIVE The purpose of this study was to investigate the clinical and demographic features of SSS patients carrying HCN4 mutations. METHODS We genetically screened 38 unrelated SSS families and functionally analyzed the mutant SCN5A and HCN4 channels by patch clamping. We also evaluated the clinical features of familial SSS by a meta-analysis of 48 SSS probands with mutations in HCN4 (n = 16) and SCN5A (n = 32), including previously reported cases, and 538 sporadic SSS cases. RESULTS We identified two HCN4 and three SCN5A loss-of-function mutations in our familial SSS cohort. Meta-analysis of HCN4 mutation carriers showed a significantly younger age at diagnosis (39.1 ± 21.7 years) than in sporadic SSS (74.3 ± 0.4 years; P <.001), but a significantly older age than in SCN5A mutation carriers (20.0 ± 17.6 years; P = .003). Moreover, HCN4 mutation carriers were more frequently associated with AF (43.8%) and LVNC (50%) and with older age at pacemaker implantation (43.5 ± 22.1 years) than were SCN5A mutation carriers (17.8 ± 16.5 years; P <.001). CONCLUSION SSS with HCN4 mutations may form a distinct SSS subgroup characterized by early clinical manifestation after adolescence and frequent association with AF and LVNC.
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Affiliation(s)
- Taisuke Ishikawa
- Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Takashi Murakami
- Department of Cardiology, Ibaraki Children's Hospital, Mito, Japan
| | - Kentaro Yoshida
- Department of Cardiology, Ibaraki Prefectural Central Hospital, Kasama, Japan
| | - Hiroyuki Mishima
- Department of Cardiology, Ibaraki Prefectural Central Hospital, Kasama, Japan
| | - Tetsuya Fukuoka
- Department of Pediatrics, Shizuoka Saiseikai General Hospital, Shizuoka, Japan
| | - Hiroki Kimoto
- Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Risa Sakamoto
- Department of Medicine, Nagasaki University, Nagasaki, Japan
| | - Takafumi Ohkusa
- Department of Medicine, Nagasaki University, Nagasaki, Japan
| | - Takeshi Aiba
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita ,Japan
| | - Akihiko Nogami
- Department of Cardiology, Tsukuba University, Tsukuba, Japan
| | - Naokata Sumitomo
- Department of Pediatric Cardiology, Saitama Medical University, Saitama, Japan
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita ,Japan; Division of Cardiology, Nippon Medical School, Tokyo, Japan
| | - Koh-Ichiro Yoshiura
- Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Naomasa Makita
- Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
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Núñez L, Crespo-Leiro MG, Marrón-Liñares GM, Suarez-Fuentetaja N, Barge-Caballero E, Paniagua-Martín MJ, Marzoa-Rivas R, Grille-Cancela Z, Muñiz-García J, Vazquez-Rodriguez JM, Hermida-Prieto M. Analysis of variants in the HCN4 gene and in three single nucleotide polymorphisms of the CYP3A4 gene for association with ivabradine reduction in heart rate: A preliminary report. Cardiol J 2016; 23:573-582. [PMID: 27439367 DOI: 10.5603/cj.a2016.0050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/30/2016] [Accepted: 06/30/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Ivabradine, a selective bradycardic drug, inhibits the If. In patients with heart failure (HF), ivabradine reduces the risk of rehospitalization and mortality. The average heart rate (HR) reduction is 8-10 beats, although clinical trials reveal interindividual variability. The aim of the study is to identify variants associated with HR reduction produced by ivabradine in genes involved in the drug metabolism (CYP3A4) or related to the drug target (HCN4). METHODS In an exploratory cohort (n = 11), patients started on ivabradine were genotyped and the HR reduction was studied. RESULTS The mean HR reduction after the treatment was 18.10 ± 12.26 bpm. The HR reduction was ≥ 15 bpm in 3 patients and > 5 and < 15 bpm in 7 patients. Four synonymous variants, L12L, L520L, P852P, and P1200P, were detected in the HCN4 gene (frequency = 0.045, 0.045, and 0.681, respectively). Moreover, the CYP3A4*1F and CYP3A4*1B were found in one patient each and CYP3A4*1G was presented in 3 patients. CONCLUSIONS This is the first study using an exploratory pharmacogenetic approach that attempts to explain interindividual variability in ivabradine HR reduction. However, more research must be undertaken in order to determine the role of variants in HCN4 and CYP3A4 genes in response to ivabradine.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Manuel Hermida-Prieto
- Grupo de investigación en Cardiología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). Spain..
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Feng Y, Luo S, Yang P, Song Z. Electric pulse current stimulation increases electrophysiological properties of I f current reconstructed in m HCN4-transfected canine mesenchymal stem cells. Exp Ther Med 2016; 11:1323-9. [PMID: 27073443 DOI: 10.3892/etm.2016.3072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 01/28/2016] [Indexed: 01/11/2023] Open
Abstract
The 'funny' current, also known as the If current, play a crucial role in the spontaneous diastolic depolarization of sinoatrial node cells. The If current is primarily induced by the protein encoded by the hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) gene. The functional If channel can be reconstructed in canine mesenchymal stem cells (cMSCs) transfected with mouse HCN4 (mHCN4). Biomimetic studies have shown that electric pulse current stimulation (EPCS) can promote cardiogenesis in cMSCs. However, whether EPCS is able to influence the properties of the If current reconstructed in mHCN4-transfected cMSCs remains unclear. The present study aimed to investigate the effects of EPCS on the If current reconstructed in mHCN4-transfected cMSCs. The cMSCs were transfected with the lentiviral vector pLentis-mHCN4-GFP. Following transfection, these cells were divided into two groups: mHCN4-transfected cMSCs (group A), and mHCN4-transfected cMSCs induced by EPCS (group B). Using a whole cell patch-clamp technique, the If current was recorded, and group A cMSCs showed significant time and voltage dependencies and sensitivity to extracellular Cs+. The half-maximal activation (V1/2) value was -101.2±4.6 mV and the time constant of activation was 324±41 msec under -160 mV. In the group B cells the If current increased obviously and activation curve moved to right. The absolute value of V1/2 increased significantly to -92.4±4.8 mV (P<0.05), and the time constant of activation diminished under the same command voltage (251±44 vs. 324±41, P<0.05). In addition, the mRNA and protein expression levels of HCN4, connexin 43 (Cx43) and Cx45 were upregulated in group B compared with group A, as determined by reverse transcription-quantitative polymerase chain reaction and western blot analyses. Transmission electron micrographs also confirmed the increased gap junctions in group B. Collectively, these results indicated that reconstructed If channels may have a positive regulatory role in EPCS induction. The cMSCs transfected with mHCN4 induced by EPCS may be a source of effective biological pacemaker cells.
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Qiu X, Guo Q, Xiong W, Yang X, Tang YQ. Therapeutic effect of astragaloside-IV on bradycardia is involved in up-regulating klotho expression. Life Sci 2016; 144:94-102. [PMID: 26593401 DOI: 10.1016/j.lfs.2015.11.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/16/2015] [Accepted: 11/20/2015] [Indexed: 11/23/2022]
Abstract
AIMS In order to determine whether klotho is involved in the therapeutic effects of Astragaloside-IV on bradycardia, we evaluated the effect of ASG-IV on klotho and the effect of klotho on HCN4 and If. MAIN METHODS Administrating isoproterenol (5 mg/kg) for 15 days to establish a rat bradycardia model randomized SD rats into control, model (ISO) and ASG-IV (5 mg/kg/day) groups to explore the effect of ASG-IV on klotho. Rats were sacrificed on day 15 after heart rate and heart function were measured; SAN tissues were collected to measure the expression of klotho and HCN4. In vitro, neonatal rat myocardial cells were incubated with LPS for 24 h to inhibit the expression of HCN4 and incubated with LPS+ klotho to explore the effect of klotho on HCN4 expression. We also adopted full-patch-clamp technique to explore the effect of klotho on If. KEY FINDINGS Heart rate in model group was significantly decreased (356.6±19.7 vs. 428.9±19.9 in control group, P<0.01) and ASG-IV can increase heart rate (401.4±12.0 vs. 356.6±19.7 in model group, P<0.01). The expression of klotho was also up-regulated (P<0.05). In vitro, after incubation with LPS for 24h, HCN4 expression was significantly decreased in neonatal rat myocardial cells (0.6±0.07 vs. 1.0, P<0.01) and If was significantly declined. Exogenous klotho showed protective effect on HCN4 expression (1.58±0.16 in ASG-IV group vs. 0.6±0.07 in LPS group, P<0.05) and If. SIGNIFICANCE Klotho is involved in the treatment mechanism of ASG-IV.
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Melgari D, Brack KE, Zhang C, Zhang Y, El Harchi A, Mitcheson JS, Dempsey CE, Ng GA, Hancox JC. hERG potassium channel blockade by the HCN channel inhibitor bradycardic agent ivabradine. J Am Heart Assoc 2015; 4:jah3927. [PMID: 25911606 PMCID: PMC4579960 DOI: 10.1161/jaha.115.001813] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Background Ivabradine is a specific bradycardic agent used in coronary artery disease and heart failure, lowering heart rate through inhibition of sinoatrial nodal HCN‐channels. This study investigated the propensity of ivabradine to interact with KCNH2‐encoded human Ether‐à‐go‐go–Related Gene (hERG) potassium channels, which strongly influence ventricular repolarization and susceptibility to torsades de pointes arrhythmia. Methods and Results Patch clamp recordings of hERG current (IhERG) were made from hERG expressing cells at 37°C. IhERG was inhibited with an IC50 of 2.07 μmol/L for the hERG 1a isoform and 3.31 μmol/L for coexpressed hERG 1a/1b. The voltage and time‐dependent characteristics of IhERG block were consistent with preferential gated‐state‐dependent channel block. Inhibition was partially attenuated by the N588K inactivation‐mutant and the S624A pore‐helix mutant and was strongly reduced by the Y652A and F656A S6 helix mutants. In docking simulations to a MthK‐based homology model of hERG, the 2 aromatic rings of the drug could form multiple π‐π interactions with the aromatic side chains of both Y652 and F656. In monophasic action potential (MAP) recordings from guinea‐pig Langendorff‐perfused hearts, ivabradine delayed ventricular repolarization and produced a steepening of the MAPD90 restitution curve. Conclusions Ivabradine prolongs ventricular repolarization and alters electrical restitution properties at concentrations relevant to the upper therapeutic range. In absolute terms ivabradine does not discriminate between hERG and HCN channels: it inhibits IhERG with similar potency to that reported for native If and HCN channels, with S6 binding determinants resembling those observed for HCN4. These findings may have important implications both clinically and for future bradycardic drug design.
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Affiliation(s)
- Dario Melgari
- School of Physiology & Pharmacology, Medical Sciences Building, Bristol, United Kingdom (D.M., Y.Z., A.E.H., J.C.H.)
| | - Kieran E Brack
- Department of Cardiovascular Sciences, Cardiology Group, Glenfield Hospital, University of Leicester, United Kingdom (K.E.B., C.Z., A.N.)
| | - Chuan Zhang
- Department of Cardiovascular Sciences, Cardiology Group, Glenfield Hospital, University of Leicester, United Kingdom (K.E.B., C.Z., A.N.)
| | - Yihong Zhang
- School of Physiology & Pharmacology, Medical Sciences Building, Bristol, United Kingdom (D.M., Y.Z., A.E.H., J.C.H.)
| | - Aziza El Harchi
- School of Physiology & Pharmacology, Medical Sciences Building, Bristol, United Kingdom (D.M., Y.Z., A.E.H., J.C.H.)
| | - John S Mitcheson
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, Leicester, United Kingdom (J.S.M.)
| | | | - G André Ng
- Department of Cardiovascular Sciences, Cardiology Group, Glenfield Hospital, University of Leicester, United Kingdom (K.E.B., C.Z., A.N.) NIHR Leicester Cardiovascular Biomedical Research Unit, Leicester, United Kingdom (A.N.)
| | - Jules C Hancox
- School of Physiology & Pharmacology, Medical Sciences Building, Bristol, United Kingdom (D.M., Y.Z., A.E.H., J.C.H.)
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Abstract
The hyperpolarization-activated 'funny' current, If, plays an important modulating role in the pacemaker activity of the human sinoatrial node (SAN). If is carried by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are tetramers built of four HCN subunits. In human SAN, HCN4 is the most abundant of the four isoforms of the HCN family. Since 2003, several loss-of-function mutations in the HCN4 gene, which encodes the HCN4 protein, or in the KCNE2 gene, which encodes the MiRP1 accessory β-subunit, have been associated with sinus node dysfunction. Voltage-clamp experiments on HCN4 channels expressed in COS-7 cells, Xenopus oocytes, or HEK-293 cells have revealed changes in the expression and kinetics of mutant channels, but the extent to which these changes would affect If flowing during a human SAN action potential is unresolved. Here, we review the changes in expression and kinetics of HCN4 mutant channels and provide an overview of their effects on If during the time course of a human SAN action potential, both under resting conditions and upon adrenergic stimulation. These effects are assessed in simulated action potential clamp experiments, with action potentials recorded from isolated human SAN pacemaker cells as command potential and kinetics of If based on voltage-clamp data from these cells. Results from in vitro and in silico experiments show several inconsistencies with clinical observations, pointing to challenges for future research.
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Affiliation(s)
- Arie O Verkerk
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands
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Towbin JA. Ion channel dysfunction associated with arrhythmia, ventricular noncompaction, and mitral valve prolapse: a new overlapping phenotype. J Am Coll Cardiol 2014; 64:768-71. [PMID: 25145519 DOI: 10.1016/j.jacc.2014.06.1154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 06/24/2014] [Indexed: 10/24/2022]
Affiliation(s)
- Jeffrey A Towbin
- The Heart Institute, Division of Pediatric Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
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40
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Schweizer PA, Schröter J, Greiner S, Haas J, Yampolsky P, Mereles D, Buss SJ, Seyler C, Bruehl C, Draguhn A, Koenen M, Meder B, Katus HA, Thomas D. The symptom complex of familial sinus node dysfunction and myocardial noncompaction is associated with mutations in the HCN4 channel. J Am Coll Cardiol 2014; 64:757-67. [PMID: 25145518 DOI: 10.1016/j.jacc.2014.06.1155] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/26/2014] [Accepted: 06/02/2014] [Indexed: 01/24/2023]
Abstract
BACKGROUND Inherited arrhythmias were originally considered isolated electrical defects. There is growing evidence that ion channel dysfunction also contributes to myocardial disorders, but genetic overlap has not been reported for sinus node dysfunction (SND) and noncompaction cardiomyopathy (NCCM). OBJECTIVES The study sought to investigate a familial electromechanical disorder characterized by SND and NCCM, and to identify the underlying genetic basis. METHODS The index family and a cohort of unrelated probands with sinus bradycardia were examined by electrocardiography, Holter recording, exercise stress test, echocardiography, and/or cardiac magnetic resonance imaging. Targeted next-generation and direct sequencing were used for candidate gene analysis and mutation scanning. Ion channels were expressed in HEK293 cells and studied using patch-clamp recordings. RESULTS SND and biventricular NCCM were diagnosed in multiple members of a German family. Segregation analysis suggested autosomal-dominant inheritance of the combined phenotype. When looking for potentially disease-causing gene variants with cosegregation, a novel hyperpolarization-activated cyclic nucleotide channel 4 (HCN4)-G482R mutation and a common cysteine and glycine-rich protein 3 (CSRP3)-W4R variant were identified. HCN4-G482R is located in the highly conserved channel pore domain. Mutant subunits were nonfunctional and exerted dominant-negative effects on wild-type current. CSRP3-W4R has previously been linked to dilated and hypertrophic cardiomyopathy, but was also found in healthy subjects. Moreover, different truncation (695X) and missense (P883R) HCN4 mutations segregated with a similar combined phenotype in an additional, unrelated family and a single unrelated proband respectively, which both lacked CSRP3-W4R. CONCLUSIONS The symptom complex of SND and NCCM is associated with heritable HCN4 defects. The NCCM phenotype may be aggravated by a common CSRP3 variant in one of the families.
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Affiliation(s)
- Patrick A Schweizer
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany.
| | - Julian Schröter
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; Institute for Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Sebastian Greiner
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Jan Haas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Pessah Yampolsky
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Derliz Mereles
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Sebastian J Buss
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Claudia Seyler
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Claus Bruehl
- Institute for Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Andreas Draguhn
- Institute for Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Michael Koenen
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; Institute for Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany; Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, Heidelberg, Germany
| | - Benjamin Meder
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany.
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Newton CM, Stoyek MR, Croll RP, Smith FM. Regional innervation of the heart in the goldfish, Carassius auratus: a confocal microscopy study. J Comp Neurol 2014; 522:456-78. [PMID: 23853005 DOI: 10.1002/cne.23421] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 06/24/2013] [Accepted: 07/03/2013] [Indexed: 11/09/2022]
Abstract
The intracardiac nervous system represents the final common pathway for autonomic control of the vertebrate heart in maintaining cardiovascular homeostasis. In teleost fishes, details of the organization of this system are not well understood. Here we investigated innervation patterns in the heart of the goldfish, a species representative of a large group of cyprinids. We used antibodies against the neuronal markers zn-12, acetylated tubulin, and human neuronal protein C/D, as well as choline acetyltransferase, tyrosine hydroxylase, nitric oxide synthetase, and vasoactive intestinal polypeptide (VIP) to detect neural elements and their transmitter contents in wholemounts and sections of cardiac tissue. All chambers of the heart were innervated by choline acetyltransferase-positive axons, implying cholinergic regulation; and by tyrosine hydroxylase-containing axons, implying adrenergic regulation. The mean total number of intracardiac neurons was 713 ± 78 (SE), nearly half of which were cholinergic. Neuronal somata were mainly located in a ganglionated plexus around the sinoatrial valves. Somata were contacted by cholinergic, adrenergic, nitrergic, and VIP-positive terminals. Putative pacemaker cells, identified by immunoreactivity for hyperpolarization activated, cyclic nucleotide-gated channel 4, were located in the base of the sinoatrial valves, and this region was densely innervated by cholinergic and adrenergic terminals. We have shown that the goldfish heart possesses the necessary neuroanatomical substrate for fine, region-by-region autonomic control of the myocardial effectors that are involved in determining cardiac output.
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Affiliation(s)
- Cecilia M Newton
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
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Pauza DH, Rysevaite K, Inokaitis H, Jokubauskas M, Pauza AG, Brack KE, Pauziene N. Innervation of sinoatrial nodal cardiomyocytes in mouse. A combined approach using immunofluorescent and electron microscopy. J Mol Cell Cardiol 2014; 75:188-97. [PMID: 25101952 DOI: 10.1016/j.yjmcc.2014.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/10/2014] [Accepted: 07/28/2014] [Indexed: 11/28/2022]
Abstract
Fluorescent immunohistochemistry on the cardiac conduction system in whole mount mouse heart preparations demonstrates a particularly dense and complex network of nerve fibres and cardiomyocytes which are positive to the hyperpolarization activated cyclic nucleotide-gated potassium channel 4 (HCN4-positive cardiomyocytes) in the sinoatrial node region and adjacent areas around the root of right cranial vein. The present study was designed to investigate the morphologic and histochemical pattern of nerve fibres and HCN4-positive cardiomyocytes using fluorescent techniques and/or electron microscopy. Adrenergic and cholinergic nerve fibres together with HCN4-positive cardiomyocytes were identified using primary antibodies for tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), and the HCN4 channel respectively. Amid HCN4-positive cardiomyocytes, fluorescence and electron microscopy data demonstrated a dense distribution of nerve fibres immunoreactive for ChAT and TH. In addition, novel electron microscopy data revealed that the mouse sinoatrial node contained exclusively unmyelinated nerve fibres, in which the majority of axons possess varicosities with clear mediatory vesicles that can be classified as cholinergic. Synapses occurred without any clear terminal connection with the effector cell, i.e. these synapes were of "en passant" type. In general, the morphologic pattern of innervation of mouse HCN4-positive cardiomyocytes identified using electron microscopy corresponds well to the dense network of nerve fibres demonstrated by fluorescent immunohistochemistry in mouse sinoatrial node and adjacent areas. The complex and extraordinarily dense innervation of HCN4-positive cardiomyocytes in mouse sinoatrial node underpins the importance of neural regulation for the cardiac conduction system. Based on the present observations, it is concluded that the occurrence of numerous nerve fibres nearby atrial cardiomyocytes serves as a novel reliable extracellular criterion for discrimination of SA nodal cardiomyocytes using electron microscopy.
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Affiliation(s)
- Dainius H Pauza
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania.
| | - Kristina Rysevaite
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Hermanas Inokaitis
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Marius Jokubauskas
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Audrys G Pauza
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Kieran E Brack
- Department of Cardiovascular Sciences and NIHR Leicester Cardiovascular Biomedical Research Unit, University of Leicester, Leicester, UK
| | - Neringa Pauziene
- Institute of Anatomy, Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
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Macri V, Mahida SN, Zhang ML, Sinner MF, Dolmatova EV, Tucker NR, McLellan M, Shea MA, Milan DJ, Lunetta KL, Benjamin EJ, Ellinor PT. A novel trafficking-defective HCN4 mutation is associated with early-onset atrial fibrillation. Heart Rhythm 2014; 11:1055-1062. [PMID: 24607718 DOI: 10.1016/j.hrthm.2014.03.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia, and a recent genome-wide association study identified the hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) as a novel AF susceptibility locus. HCN4 encodes for the cardiac pacemaker channel, and HCN4 mutations are associated with familial sinus bradycardia and AF. OBJECTIVE The purpose of this study was to determine whether novel variants in the coding region of HCN4 contribute to the susceptibility for AF. METHODS We sequenced the coding region of HCN4 for novel variants from 527 cases with early-onset AF from the Massachusetts General Hospital AF Study and 443 referents from the Framingham Heart Study. We used site-directed mutagenesis, cellular electrophysiology, immunocytochemistry, and confocal microscopy to functionally characterize novel variants. RESULTS We found the frequency of novel coding HCN4 variants was 2-fold greater for individuals with AF (7 variants) compared to the referents (3 variants). We determined that of the 7 novel HCN4 variants in our AF cases, 1 (p.Pro257Ser, located in the amino-terminus adjacent to the first transmembrane spanning domain) did not traffic to cell membrane, whereas the remaining 6 were not functionally different from wild type. In addition, the 3 novel variants in our referents did not alter function compared to wild-type. Coexpression studies showed that the p.Pro257Ser mutant channel failed to colocalize with the wild-type HCN4 channel on the cell membrane. CONCLUSION Our findings are consistent with HCN4 haploinsufficiency as the likely mechanism for early-onset AF in the p.Pro257Ser carrier.
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Affiliation(s)
- Vincenzo Macri
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Saagar N Mahida
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Michael L Zhang
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Moritz F Sinner
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Department of Medicine I, University Hospital Grosshadern, Ludwig-Maximilians University, Munich, Germany.,National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study, Framingham, Massachusetts, USA
| | - Elena V Dolmatova
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Nathan R Tucker
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Micheal McLellan
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Marisa A Shea
- Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - David J Milan
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Kathryn L Lunetta
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.,Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA.,National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study, Framingham, Massachusetts, USA
| | - Emelia J Benjamin
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.,Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA.,National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study, Framingham, Massachusetts, USA.,Preventive Medicine Section, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA.,Cardiology Section, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Patrick T Ellinor
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA.,Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, Massachusetts, USA
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44
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Chiu SN, Lin LY, Wang JK, Lu CW, Chang CW, Lin MT, Hua YC, Lue HC, Wu MH. Long-term outcomes of pediatric sinus bradycardia. J Pediatr 2013; 163:885-9.e1. [PMID: 23623512 DOI: 10.1016/j.jpeds.2013.03.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 03/04/2013] [Accepted: 03/19/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To delineate the long-term outcomes and mechanisms of pediatric sinus bradycardia. STUDY DESIGN Participants with sinus bradycardia who were identified from a survey of 432,166 elementary and high school students, were enrolled 10 years after the survey. The clinical course, heart rate variability, and hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4) gene were assessed. RESULTS A total of 104 (male:female was 60:44; prevalence, 0.025%) participants were observed to have sinus bradycardia at age 15.5 ± 0.2 years with a mean heart rate of 48.4 ± 0.4 beats per minute; 86 study participants (83%) responded to clinical assessment and 37 (36%) underwent laboratory assessment. Athletes composed 37.8% of the study participants. During the extended 10-year follow-up, 15 (17%) of the participants had self-limited syncopal episodes, but none had experienced life-threatening events. According to Holter recordings, none of the participants had heart rate <30 beats per minute or a pause longer than 3 seconds. Compared with 67 age- and sex-matched controls, the variables of heart rate based on the spectral and time domain analysis of the participants with sinus bradycardia were all significantly higher, indicating higher parasympathetic activity. The results of mutation analysis were negative in the HCN4 gene in all of our participants. CONCLUSIONS The long-term outcomes of the children and adolescents with sinus bradycardia identified using school electrocardiographic survey are favorable. Parasympathetic hyperactivity, instead of HCN4 gene mutation, is responsible for the occurrence of sinus bradycardia.
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Affiliation(s)
- Shuenn-Nan Chiu
- Department of Pediatrics, National Taiwan University Hospital and Medical College, National Taiwan University, Taipei, Taiwan
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45
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Zhang H, Li S, Qu D, Li B, He B, Wang C, Xu Z. Autologous biological pacing function with adrenergic-responsiveness in porcine of complete heart block. Int J Cardiol 2013; 168:3747-51. [PMID: 23835270 DOI: 10.1016/j.ijcard.2013.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 04/12/2013] [Accepted: 06/15/2013] [Indexed: 11/30/2022]
Abstract
AIMS To assess the efficacy of autologous biological pacing function by autograft of gene-transferred mesenchymal stem cells in a porcine model of complete heart block. METHODS AND RESULTS Fourteen healthy young male pigs were randomized into active group (n=8) and control group (n=6). Porcine MSCs were transfected with Ad.HCN4 or Ad.Null. The pacemaker function of transfected MSCs was studied by whole-cell patch clamp. The CHB model of porcine was created with transthoracic ablation technique and the transfected MSCs were autografted into the free wall of right ventricle. The pacing function was studied by ECG and ambulatory Holter recording weekly. The adrenergic responsiveness was evaluated by the variation of heart rate after isoprenaline infusion or food provision following an overnight fasting. HCN4-MSCs expressed a robust time-dependent inward current (If) and the current density of If was 4.3±0.6 pA/pF at -105 mV. In week 2 after autograft, the heart rate of active group became significantly higher than control (53±5 bpm vs. 38±4 bpm, P<0.05) and the percent of pacing beats in active group was higher than control (69±10% vs. 28±8%, P<0.05). By infusion of isoprenaline, the heart rate was increased significantly in both groups. However, there was a significant increase of heart rate when presenting food for active group (P<0.05) while not in control. CONCLUSIONS Our findings demonstrated that autografted HCN4-MSCs could increase the heart rate by providing an adrenergic-responsive biological pacing function, indicating a promising approach without immunological or ethical issues for the treatment of complete heart block.
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Affiliation(s)
- Hao Zhang
- Changhai Hospital, Department of Cardiothoracic Surgery, Second Military Medical University, Shanghai, China
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46
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Abstract
Hyperpolarization-activated, cyclic nucleotide-sensitive (HCN4) channels produce the "funny current," I(f), which contributes to spontaneous pacemaking in sinoatrial myocytes (SAMs). The C-terminus of HCN channels inhibits voltage-dependent gating, and cAMP binding relieves this "autoinhibition." We previously showed 1) that autoinhibition in HCN4 can be relieved in the absence of cAMP in some cellular contexts and 2) that PKA is required for β adrenergic receptor (βAR) signaling to HCN4 in SAMs. Together, these results raise the possibility that native HCN channels in SAMs may be insensitive to direct activation by cAMP. Here, we examined PKA-independent activation of If by cAMP in SAMs. We observed similar robust activation of If by exogenous cAMP and Rp-cAMP (an analog than cannot activate PKA). Thus PKA-dependent βAR-to-HCN signaling does not result from cAMP insensitivity of sinoatrial HCN channels and might instead arise via PKA-dependent limitation of cAMP production and/or cAMP access to HCN channels in SAMs.
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Affiliation(s)
- Joshua R St Clair
- Department of Physiology and Biophysics; University of Colorado Denver-Anschutz Medical Campus; Aurora, CO USA
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47
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Abstract
RATIONALE To date, there has been no specific marker of the first heart field to facilitate understanding of contributions of the first heart field to cardiac lineages. Cardiac arrhythmia is a leading cause of death, often resulting from abnormalities in the cardiac conduction system (CCS). Understanding origins and identifying markers of CCS lineages are essential steps toward modeling diseases of the CCS and for development of biological pacemakers. OBJECTIVE To investigate HCN4 as a marker for the first heart field and for precursors of distinct components of the CCS, and to gain insight into contributions of first and second heart lineages to the CCS. METHODS AND RESULTS HCN4CreERT2, -nuclear LacZ, and -H2BGFP mouse lines were generated. HCN4 expression was examined by means of immunostaining with HCN4 antibody and reporter gene expression. Lineage studies were performed using HCN4CreERT2, Isl1Cre, Nkx2.5Cre, and Tbx18Cre, coupled to coimmunostaining with CCS markers. Results demonstrated that, at cardiac crescent stages, HCN4 marks the first heart field, with HCN4CreERT2 allowing assessment of cell fates adopted by first heart field myocytes. Throughout embryonic development, HCN4 expression marked distinct CCS precursors at distinct stages, marking the entire CCS by late fetal stages. We also noted expression of HCN4 in distinct subsets of endothelium at specific developmental stages. CONCLUSIONS This study provides insight into contributions of first and second heart lineages to the CCS and highlights the potential use of HCN4 in conjunction with other markers for optimization of protocols for generation and isolation of specific conduction system precursors.
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Affiliation(s)
- Xingqun Liang
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.,Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Gang Wang
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Lizhu Lin
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Jennifer Lowe
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Qingquang Zhang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Lei Bu
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Yihan Chen
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Ju Chen
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Yunfu Sun
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.,Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Sylvia M Evans
- Skaggs School of Pharmacy and Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
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48
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Nawathe PA, Kryukova Y, Oren RV, Milanesi R, Clancy CE, Lu JT, Moss AJ, Difrancesco D, Robinson RB. An LQTS6 MiRP1 mutation suppresses pacemaker current and is associated with sinus bradycardia. J Cardiovasc Electrophysiol 2013; 24:1021-7. [PMID: 23631727 DOI: 10.1111/jce.12163] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/20/2012] [Accepted: 03/13/2013] [Indexed: 01/20/2023]
Abstract
BACKGROUND Sinus node (SN) dysfunction is observed in some long-QT syndrome (LQTS) patients, but has not been studied as a function of LQTS genotype. LQTS6 involves mutations in the hERG β-subunit MiRP1, which also interacts with hyperpolarization-activated, cyclic nucleotide gated (HCN) channels-the molecular correlate of SN pacemaker current (If ). An LQTS registry search identified a 55-year male with M54T MiRP1 mutation, history of sinus bradycardia (39-56 bpm), and prolonged QTc. OBJECTIVE We tested if LQTS6 incorporates sinus bradycardia due to abnormal If . METHODS We transiently co-transfected neonatal rat ventricular myocytes (to study currents in a myocyte background) with human HCN4 (hHCN4, primary SN isoform) or human HCN2 (hHCN2) and one of the following: empty vector, wild-type hMiRP1 (WT), M54T hMiRP1 (M54T). Current amplitude, voltage dependence, and kinetics were measured by whole cell patch clamp. RESULTS M54T co-expression decreased HCN4 current density by 80% compared to hHCN4 alone or with WT, and also slowed HCN4 activation at physiologically relevant voltages. Neither WT nor M54T altered HCN4 voltage dependence. A computer simulation predicts that these changes in HCN4 current would decrease rate and be additive with published effects of M54T mutation on hERG kinetics on rate. CONCLUSIONS We conclude that M54T LQTS6 mutation can cause sinus bradycardia through effects on both hERG and HCN currents. Patients with other LQTS6 mutations should be examined for SN dysfunction, and the effect on HCN current determined.
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