1
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Yan M, Lin K, Huang D, Li J, Qu X, Chen K. Semaglutide attenuates pathological electrophysiological remodeling in diabetic cardiomyopathy via restoring Cx43 expression. Endocrine 2024:10.1007/s12020-024-03823-2. [PMID: 38647981 DOI: 10.1007/s12020-024-03823-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/04/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Semaglutide is a relatively new anti-hyperglycemic agent that was shown to carry cardioprotective potentials. However, the exact effects of semaglutide on diabetic cardiomyopathy (DCM) and their underlining mechanism remain unclear. This study aimed to evaluate the effects of semaglutide on myocardium injury and cardiac function in DCM mice and its potential mechanisms, with emphasis on its effects on Cx43 and electrophysiological remodeling. METHODS C57BL/6 mice were randomly divided into four groups: control group, semaglutide group, diabetes group, and diabetes + semaglutide treatment group. Type 1 diabetes were induced by intraperitoneal injection of streptozotocin. Mice in the semaglutide intervention group were injected subcutaneously with semaglutide (0.15 mg/kg) every week for 8 weeks. The blood glucose, cardiac function, oxidative stress markers, apoptosis, expression of Sirt1, AMPK, Cx43, and electrocardiogram of mice in each group were evaluated. RESULTS Treatment with semaglutide alleviated glucose metabolism disorders and improved cardiac dysfunction in diabetic mice. In addition, semaglutide ameliorated the increase in oxidative stress and apoptosis in diabetic heart. Sirt1/AMPK pathway was activated after semaglutide treatment. Furthermore, diabetic mice showed reduced expression of Cx43 in the myocardium, accompanied by changes in electrocardiogram, including significantly prolonged RR, QRS, QT and QTc interval. Semaglutide treatment restored Cx43 expression and reversed the above-mentioned ECG abnormalities. CONCLUSIONS Our research results showed that semaglutide protected against oxidative stress and apoptosis in diabetic heart, thereby improving cardiac function and electrophysiological remodelling in DCM mice, which may attribute to activation of Sirt1/AMPK pathway and restore of Cx43 expression.
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Affiliation(s)
- Meiling Yan
- Department of Cardiology, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China
| | - Kaibin Lin
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Dong Huang
- Department of Cardiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Jingbo Li
- Department of Cardiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Xinkai Qu
- Department of Cardiology, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
| | - Kankai Chen
- Department of Cardiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
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2
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García-Mendívil L, Pérez-Zabalza M, Oliver-Gelabert A, Vallejo-Gil JM, Fañanás-Mastral J, Vázquez-Sancho M, Bellido-Morales JA, Vaca-Núñez AS, Ballester-Cuenca C, Diez E, Ordovás L, Pueyo E. Interindividual Age-Independent Differences in Human CX43 Impact Ventricular Arrhythmic Risk. RESEARCH (WASHINGTON, D.C.) 2023; 6:0254. [PMID: 38023417 PMCID: PMC10650968 DOI: 10.34133/research.0254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023]
Abstract
Connexin 43 (CX43) is one of the major components of gap junctions, the structures responsible for the intercellular communication and transmission of the electrical impulse in the left ventricle. There is limited information on the histological changes of CX43 with age and their effect on electrophysiology, especially in humans. Here, we analyzed left ventricular biopsies from living donors starting at midlife to characterize age-related CX43 remodeling. We assessed its quantity, degree of lateralization, and spatial heterogeneity together with fibrotic deposition. We observed no significant age-related remodeling of CX43. Only spatial heterogeneity increased slightly with age, and this increase was better explained by biological age than by chronological age. Importantly, we found that CX43 features varied considerably among individuals in our population with no relevant relationship to age or fibrosis content, in contrast to animal species. We used our experimental results to feed computational models of human ventricular electrophysiology and to assess the effects of interindividual differences in specific features of CX43 and fibrosis on conduction velocity, action potential duration, and arrhythmogenicity. We found that larger amounts of fibrosis were associated with the highest arrhythmic risk, with this risk being increased when fibrosis deposition was combined with a reduction in CX43 amount and/or with an increase in CX43 spatial heterogeneity. These mechanisms underlying high arrhythmic risk in some individuals were not associated with age in our study population. In conclusion, our data rule out CX43 remodeling as an age-related arrhythmic substrate in the population beyond midlife, but highlight its potential as a proarrhythmic factor at the individual level, especially when combined with increased fibrosis.
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Affiliation(s)
- Laura García-Mendívil
- Biomedical Signal Interpretation and Computational Simulation group (BSICoS), Aragón Institute of Engineering Research,
University of Zaragoza, Zaragoza 50018, Spain
- BSICoS, Instituto de Investigación Sanitaria Aragón (IISA), Zaragoza 50018, Spain
| | - María Pérez-Zabalza
- Biomedical Signal Interpretation and Computational Simulation group (BSICoS), Aragón Institute of Engineering Research,
University of Zaragoza, Zaragoza 50018, Spain
- BSICoS, Instituto de Investigación Sanitaria Aragón (IISA), Zaragoza 50018, Spain
- Centro Universitario de la Defensa (CUD), Zaragoza 50090, Spain
| | - Antoni Oliver-Gelabert
- Biomedical Signal Interpretation and Computational Simulation group (BSICoS), Aragón Institute of Engineering Research,
University of Zaragoza, Zaragoza 50018, Spain
- BSICoS, Instituto de Investigación Sanitaria Aragón (IISA), Zaragoza 50018, Spain
| | - José María Vallejo-Gil
- Department of Cardiovascular Surgery,
University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Javier Fañanás-Mastral
- Department of Cardiovascular Surgery,
University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Manuel Vázquez-Sancho
- Department of Cardiovascular Surgery,
University Hospital Miguel Servet, Zaragoza 50009, Spain
| | | | | | - Carlos Ballester-Cuenca
- Department of Cardiovascular Surgery,
University Hospital Miguel Servet, Zaragoza 50009, Spain
| | - Emiliano Diez
- Institute of Experimental Medicine and Biology of Cuyo (IMBECU), CONICET, Mendoza 5500, Argentina
| | - Laura Ordovás
- Biomedical Signal Interpretation and Computational Simulation group (BSICoS), Aragón Institute of Engineering Research,
University of Zaragoza, Zaragoza 50018, Spain
- BSICoS, Instituto de Investigación Sanitaria Aragón (IISA), Zaragoza 50018, Spain
- Fundación Agencia Aragonesa para la Investigación y el Desarrollo (ARAID), Zaragoza 50018, Spain
| | - Esther Pueyo
- Biomedical Signal Interpretation and Computational Simulation group (BSICoS), Aragón Institute of Engineering Research,
University of Zaragoza, Zaragoza 50018, Spain
- BSICoS, Instituto de Investigación Sanitaria Aragón (IISA), Zaragoza 50018, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza 50018, Spain
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3
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Kelm NQ, Solinger JC, Piell KM, Cole MP. Conjugated Linoleic Acid-Mediated Connexin-43 Remodeling and Sudden Arrhythmic Death in Myocardial Infarction. Int J Mol Sci 2023; 24:11208. [PMID: 37446386 DOI: 10.3390/ijms241311208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/15/2023] [Accepted: 06/19/2023] [Indexed: 07/15/2023] Open
Abstract
Connexin 43 (Cx43) is expressed in the left and right ventricles and is primarily responsible for conducting physiological responses in microvasculature. Studies have demonstrated that NADPH oxidase (NOX) enzymes are essential in cardiac redox biology and are responsible for the generation of reactive oxygen species (ROS). NOX2 is linked to left ventricular remodeling following myocardial infarction (MI). It was hypothesized that conjugated linoleic acid (cLA) treatment increases NOX-2 levels in heart tissue and disrupts connexins between the myocytes in the ventricle. Data herein demonstrate that cLA treatment significantly decreases survival in a murine model of MI. The observance of cLA-induced ventricular tachyarrhythmia's (VT) led to the subsequent investigation of the underlying mechanism in this MI model. Mice were treated with cLA for 12 h, 24 h, 48 h, or 72 h to determine possible time-dependent changes in NOX and Cx43 signaling pathways in isolated left ventricles (LV) extracted from cardiac tissue. The results suggest that ROS generation, through the stimulation of NOX2 in the LV, triggers a decrease in Cx43 levels, causing dysfunction of the gap junctions following treatment with cLA. This cascade of events may initiate VT and subsequent death during MI. Taken together, individuals at risk of MI should use caution regarding cLA consumption.
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Affiliation(s)
- Natia Qipshidze Kelm
- Department of Biochemistry and Molecular Genetics, Louisville, KY 40202, USA
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Jane C Solinger
- Department of Biochemistry and Molecular Genetics, Louisville, KY 40202, USA
| | - Kellianne M Piell
- Department of Biochemistry and Molecular Genetics, Louisville, KY 40202, USA
| | - Marsha P Cole
- Department of Biochemistry and Molecular Genetics, Louisville, KY 40202, USA
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY 40202, USA
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4
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Szeiffova Bacova B, Andelova K, Sykora M, T EB, Kurahara LH, Slezak J, Tribulova N. Distinct Cardiac Connexin-43 Expression in Hypertrophied and Atrophied Myocardium May Impact the Vulnerability of the Heart to Malignant Arrhythmias. A Pilot Study. Physiol Res 2023; 72:S37-S45. [PMID: 37294117 DOI: 10.33549/physiolres.935025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023] Open
Abstract
Our and other studies suggest that myocardial hypertrophy in response to hypertension and hyperthyroidism increases propensity of the heart to malignant arrhythmias, while these are rare in conditions of hypothyroidism or type-1 diabetes mellitus associated with myocardial atrophy. One of the crucial factors impacting the susceptibility of the heart to life-threatening arrhythmias is gap junction channel protein connexin-43 (Cx43), which ensure cell-to-cell coupling for electrical signal propagation. Therefore, we aimed to explore Cx43 protein abundance and its topology in hypertrophic and hypotrophic cardiac phenotype. Analysis were performed in left ventricular tissue of adult male spontaneously hypertensive rat (SHR), Wistar Kyoto rats treated for 8-weeks with L-thyroxine, methimazol or strepotozotocin to induce hyperthyroid, hypothyroid and type-1 diabetic status as well as non-treated animals. Results showed that comparing to healthy rats there was a decrease of total myocardial Cx43 and its variant phosphorylated at serine368 in SHR and hyperthyroid rats. Besides, enhanced localization of Cx43 was demonstrated on lateral sides of hypertrophied cardiomyocytes. In contrast, total Cx43 protein and its serine368 variant were increased in atrophied left ventricle of hypothyroid and type-1 diabetic rats. It was associated with less pronounced alterations in Cx43 topology. In parallel, the abundance of PKCepsilon, which phosphorylates Cx43 at serine368 that stabilize Cx43 function and distribution was reduced in hypertrophied heart while enhanced in atrophied once. Findings suggest that differences in the abundance of cardiac Cx43, its variant phosphorylated at serine368 and Cx43 topology may explain, in part, distinct propensity of hypertrophied and atrophied heart to malignant arrhythmias.
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Affiliation(s)
- B Szeiffova Bacova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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5
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Sykora M, Andelova K, Szeiffova Bacova B, Egan Benova T, Martiskova A, Knezl V, Tribulova N. Hypertension Induces Pro-arrhythmic Cardiac Connexome Disorders: Protective Effects of Treatment. Biomolecules 2023; 13:biom13020330. [PMID: 36830700 PMCID: PMC9953310 DOI: 10.3390/biom13020330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/16/2023] [Accepted: 01/21/2023] [Indexed: 02/11/2023] Open
Abstract
Prolonged population aging and unhealthy lifestyles contribute to the progressive prevalence of arterial hypertension. This is accompanied by low-grade inflammation and over time results in heart dysfunction and failure. Hypertension-induced myocardial structural and ion channel remodeling facilitates the development of both atrial and ventricular fibrillation, and these increase the risk of stroke and sudden death. Herein, we elucidate hypertension-induced impairment of "connexome" cardiomyocyte junctions. This complex ensures cell-to-cell adhesion and coupling for electrical and molecular signal propagation. Connexome dysfunction can be a key factor in promoting the occurrence of both cardiac arrhythmias and heart failure. However, the available literature indicates that arterial hypertension treatment can hamper myocardial structural remodeling, hypertrophy and/or fibrosis, and preserve connexome function. This suggests the pleiotropic effects of antihypertensive agents, including anti-inflammatory. Therefore, further research is required to identify specific molecular targets and pathways that will protect connexomes, and it is also necessary to develop new approaches to maintain heart function in patients suffering from primary or pulmonary arterial hypertension.
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6
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Welcome MO, Dogo D, Nikos E Mastorakis. Cellular mechanisms and molecular pathways linking bitter taste receptor signalling to cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Inflammopharmacology 2023; 31:89-117. [PMID: 36471190 PMCID: PMC9734786 DOI: 10.1007/s10787-022-01086-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/11/2022] [Indexed: 12/12/2022]
Abstract
Heart diseases and related complications constitute a leading cause of death and socioeconomic threat worldwide. Despite intense efforts and research on the pathogenetic mechanisms of these diseases, the underlying cellular and molecular mechanisms are yet to be completely understood. Several lines of evidence indicate a critical role of inflammatory and oxidative stress responses in the development and progression of heart diseases. Nevertheless, the molecular machinery that drives cardiac inflammation and oxidative stress is not completely known. Recent data suggest an important role of cardiac bitter taste receptors (TAS2Rs) in the pathogenetic mechanism of heart diseases. Independent groups of researchers have demonstrated a central role of TAS2Rs in mediating inflammatory, oxidative stress responses, autophagy, impulse generation/propagation and contractile activities in the heart, suggesting that dysfunctional TAS2R signalling may predispose to cardiac inflammatory and oxidative stress disorders, characterised by contractile dysfunction and arrhythmia. Moreover, cardiac TAS2Rs act as gateway surveillance units that monitor and detect toxigenic or pathogenic molecules, including microbial components, and initiate responses that ultimately culminate in protection of the host against the aggression. Unfortunately, however, the molecular mechanisms that link TAS2R sensing of the cardiac milieu to inflammatory and oxidative stress responses are not clearly known. Therefore, we sought to review the possible role of TAS2R signalling in the pathophysiology of cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Potential therapeutic significance of targeting TAS2R or its downstream signalling molecules in cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction is also discussed.
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Affiliation(s)
- Menizibeya O Welcome
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Nile University of Nigeria, Plot 681 Cadastral Zone, C-00 Research and Institution Area, Jabi Airport Road Bypass, FCT, Abuja, Nigeria.
| | - Dilli Dogo
- Department of Surgery, Faculty of Clinical Sciences, College of Health Sciences, Nile University of Nigeria, Abuja, Nigeria
| | - Nikos E Mastorakis
- Technical University of Sofia, Klement Ohridksi 8, Sofia, 1000, Bulgaria
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7
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Bugiardini E, Nunes AM, Oliveira‐Santos A, Dagda M, Fontelonga TM, Barraza‐Flores P, Pittman AM, Morrow JM, Parton M, Houlden H, Elliott PM, Syrris P, Maas RP, Akhtar MM, Küsters B, Raaphorst J, Schouten M, Kamsteeg E, van Engelen B, Hanna MG, Phadke R, Lopes LR, Matthews E, Burkin DJ. Integrin α7 Mutations Are Associated With Adult-Onset Cardiac Dysfunction in Humans and Mice. J Am Heart Assoc 2022; 11:e026494. [PMID: 36444867 PMCID: PMC9851448 DOI: 10.1161/jaha.122.026494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 11/02/2022] [Indexed: 11/30/2022]
Abstract
Background Integrin α7β1 is a major laminin receptor in skeletal and cardiac muscle. In skeletal muscle, integrin α7β1 plays an important role during muscle development and has been described as an important modifier of skeletal muscle diseases. The integrin α7β1 is also highly expressed in the heart, but its precise role in cardiac function is unknown. Mutations in the integrin α7 gene (ITGA7) have been reported in children with congenital myopathy. Methods and Results In this study, we described skeletal and cardiac muscle pathology in Itga7-/- mice and 5 patients from 2 unrelated families with ITGA7 mutations. Proband in family 1 presented a homozygous c.806_818del [p.S269fs] variant, and proband in family 2 was identified with 2 intron variants in the ITGA7 gene. The complete absence of the integrin α7 protein in muscle supports the ITGA7 mutations are pathogenic. We performed electrocardiography, echocardiography, or cardiac magnetic resonance imaging, and histological biopsy analyses in patients with ITGA7 deficiency and Itga7-/- mice. The patients exhibited cardiac dysrhythmia and dysfunction from the third decade of life and late-onset respiratory insufficiency, but with relatively mild limb muscle involvement. Mice demonstrated corresponding abnormalities in cardiac conduction and contraction as well as diaphragm muscle fibrosis. Conclusions Our data suggest that loss of integrin α7 causes a novel form of adult-onset cardiac dysfunction indicating a critical role for the integrin α7β1 in normal cardiac function and highlights the need for long-term cardiac monitoring in patients with ITGA7-related congenital myopathy.
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Affiliation(s)
- Enrico Bugiardini
- Queen Square Centre for Neuromuscular DiseasesQueen Square Institute of Neurology, UCL and National Hospital for Neurology and NeurosurgeryLondonUnited Kingdom
| | - Andreia M. Nunes
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
| | - Ariany Oliveira‐Santos
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
| | - Marisela Dagda
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
| | - Tatiana M. Fontelonga
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
| | - Pamela Barraza‐Flores
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
| | - Alan M. Pittman
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUnited Kingdom
- St George’sUniversity of LondonLondonUnited Kingdom
| | - Jasper M. Morrow
- Queen Square Centre for Neuromuscular DiseasesQueen Square Institute of Neurology, UCL and National Hospital for Neurology and NeurosurgeryLondonUnited Kingdom
| | - Matthew Parton
- Queen Square Centre for Neuromuscular DiseasesQueen Square Institute of Neurology, UCL and National Hospital for Neurology and NeurosurgeryLondonUnited Kingdom
| | - Henry Houlden
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUnited Kingdom
| | - Perry M. Elliott
- Barts Heart Centre, Barts Health NHS TrustLondonUnited Kingdom
- Centre for Heart Muscle DiseaseInstitute of Cardiovascular Science, University College LondonLondonUnited Kingdom
| | - Petros Syrris
- Centre for Heart Muscle DiseaseInstitute of Cardiovascular Science, University College LondonLondonUnited Kingdom
| | - Roderick P. Maas
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviourRadboud University Medical CenterNijmegenThe Netherlands
| | - Mohammed M. Akhtar
- Barts Heart Centre, Barts Health NHS TrustLondonUnited Kingdom
- Centre for Heart Muscle DiseaseInstitute of Cardiovascular Science, University College LondonLondonUnited Kingdom
| | - Benno Küsters
- Department of PathologyRadboud University Medical CenterNijmegenThe Netherlands
| | - Joost Raaphorst
- Department of Neurology, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam NeuroscienceAmsterdamThe Netherlands
| | - Meyke Schouten
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Erik‐Jan Kamsteeg
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Baziel van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviourRadboud University Medical CenterNijmegenThe Netherlands
| | - Michael G. Hanna
- Queen Square Centre for Neuromuscular DiseasesQueen Square Institute of Neurology, UCL and National Hospital for Neurology and NeurosurgeryLondonUnited Kingdom
| | - Rahul Phadke
- Division of NeuropathologyUCL Institute of NeurologyLondonUnited Kingdom
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular DiseasesUCL Great Ormond Street Institute of Child HealthLondonUnited Kingdom
| | - Luis R. Lopes
- Barts Heart Centre, Barts Health NHS TrustLondonUnited Kingdom
- Centre for Heart Muscle DiseaseInstitute of Cardiovascular Science, University College LondonLondonUnited Kingdom
| | - Emma Matthews
- The Atkinson Morley Neuromuscular Centre and Regional Neurosciences CentreSt George’s University Hospitals NHS Foundation TrustLondonUnited Kingdom
- Molecular and Clinical Sciences Research Institute, St George’s University of LondonLondonUnited Kingdom
| | - Dean J. Burkin
- Department of PharmacologyUniversity of Nevada Reno, School of Medicine, Center for Molecular MedicineRenoNV
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8
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Han Y, Xiong C, Zhang LZ, Wang YD, Yang G, Guo Z. Antagonism of N/OFQ attenuates externalization of β1-adrenergic receptor and ventricular arrhythmias in acute myocardial ischemia rat model. Eur J Pharmacol 2022; 929:175139. [PMID: 35809655 DOI: 10.1016/j.ejphar.2022.175139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/02/2022] [Accepted: 07/02/2022] [Indexed: 11/18/2022]
Abstract
Nociceptin/orphanin FQ (N/OFQ) and adrenergic activations play roles in promoting cardiac arrhythmia in acute myocardial ischemia but whether N/OFQ and β1-adrenergic activities interact and how they interact in the arrhythmogenesis are still unknown. We designed this study to investigate the potential interaction of N/OFQ and β1-adrenergic activities and the underlying mechanism in arrhythmogenesis in acute myocardial ischemia. Ventricular arrhythmia was evaluated in anaesthetized rats following permanent coronary artery occlusion (CAO), in presence and absence of UFP-101 (a selective antagonist of N/OFQ receptor). The changes of β1-adrenergic receptor (β1-AR) in plasma membrane of cardiomyocytes were quantitatively evaluated and the relations with the alterations of phosphorylated Raf kinase inhibitor protein (p-RKIP) and phosphorylated connexin 43 (p-Cx43) were investigated. The ventricular arrhythmia was 59% less in the animals pre-treated with UFP-101 than the placebo-treated control (difference of means = -2.41; 95% confidence interval (CI) -2.84 to -1.99; P < 0.001). Meanwhile, p-RKIP and membrane β1-AR in the myocardium were downregulated by 59% and 24%, respectively (p-RKIP: difference of means = -6.91; 95% CI -8.38 to -5.45; P < 0.001; membrane β1-AR difference of means = -27.06; 95% CI -29.89 to -24.23; P < 0.001). Artificial upregulation of RKIP by didymin significant increased β1-AR in plasma membrane of the cardiomyocytes in the animals prone to ventricular arrhythmia. The findings may suggest that activation of N/OFQ receptor in acute myocardial ischemia induces upregulation of p-RKIP, externalization of β1-adrenergic receptor and downregulation of p-Cx43 in the cardiomyocytes, which promotes ventricular arrhythmia.
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Affiliation(s)
- Yi Han
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China; Department of Anaesthesia, Second Hospital of Shanxi Medical University, 382 Wuyi Road, Taiyuan, 030001, Shanxi, China
| | - Chang Xiong
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China
| | - Lin-Zhong Zhang
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China; Department of Anaesthesia, Second Hospital of Shanxi Medical University, 382 Wuyi Road, Taiyuan, 030001, Shanxi, China
| | - Yi-Di Wang
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China
| | - Guang Yang
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China
| | - Zheng Guo
- College of Anaesthesia, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China; Department of Anaesthesia, Second Hospital of Shanxi Medical University, 382 Wuyi Road, Taiyuan, 030001, Shanxi, China; Key Laboratory of Cellular Physiology (Shanxi Medical University), National Education Commission, Shanxi Medical University, 86 Xinjiannan Road, Taiyuan, 030001, Shanxi, China.
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9
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Guo YH, Yang YQ. Atrial Fibrillation: Focus on Myocardial Connexins and Gap Junctions. BIOLOGY 2022; 11:489. [PMID: 35453689 PMCID: PMC9029470 DOI: 10.3390/biology11040489] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Atrial fibrillation (AF) represents the most common type of clinical cardiac arrhythmia worldwide and contributes to substantial morbidity, mortality and socioeconomic burden. Aggregating evidence highlights the strong genetic basis of AF. In addition to chromosomal abnormalities, pathogenic mutations in over 50 genes have been causally linked to AF, of which the majority encode ion channels, cardiac structural proteins, transcription factors and gap junction channels. In the heart, gap junctions comprised of connexins (Cxs) form intercellular pathways responsible for electrical coupling and rapid coordinated action potential propagation between adjacent cardiomyocytes. Among the 21 isoforms of connexins already identified in the mammal genomes, 5 isoforms (Cx37, Cx40, Cx43, Cx45 and Cx46) are expressed in human heart. Abnormal electrical coupling between cardiomyocytes caused by structural remodeling of gap junction channels (alterations in connexin distribution and protein levels) has been associated with enhanced susceptibility to AF and recent studies have revealed multiple causative mutations or polymorphisms in 4 isoforms of connexins predisposing to AF. In this review, an overview of the genetics of AF is made, with a focus on the roles of mutant myocardial connexins and gap junctions in the pathogenesis of AF, to underscore the hypothesis that cardiac connexins are a major molecular target in the management of AF.
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Affiliation(s)
- Yu-Han Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
- Cardiovascular Research Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
- Center Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
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10
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Chen SN, Lam CK, Wan YW, Gao S, Malak OA, Zhao SR, Lombardi R, Ambardekar AV, Bristow MR, Cleveland J, Gigli M, Sinagra G, Graw S, Taylor MR, Wu JC, Mestroni L. Activation of PDGFRA signaling contributes to filamin C-related arrhythmogenic cardiomyopathy. SCIENCE ADVANCES 2022; 8:eabk0052. [PMID: 35196083 PMCID: PMC8865769 DOI: 10.1126/sciadv.abk0052] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 12/25/2021] [Indexed: 05/07/2023]
Abstract
FLNC truncating mutations (FLNCtv) are prevalent causes of inherited dilated cardiomyopathy (DCM), with a high risk of developing arrhythmogenic cardiomyopathy. We investigated the molecular mechanisms of mutant FLNC in the pathogenesis of arrhythmogenic DCM (a-DCM) using patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). We demonstrated that iPSC-CMs from two patients with different FLNCtv mutations displayed arrhythmias and impaired contraction. FLNC ablation induced a similar phenotype, suggesting that FLNCtv are loss-of-function mutations. Coimmunoprecipitation and proteomic analysis identified β-catenin (CTNNB1) as a downstream target. FLNC deficiency induced nuclear translocation of CTNNB1 and subsequently activated the platelet-derived growth factor receptor alpha (PDGFRA) pathway, which were also observed in human hearts with a-DCM and FLNCtv. Treatment with the PDGFRA inhibitor, crenolanib, improved contractile function of patient iPSC-CMs. Collectively, our findings suggest that PDGFRA signaling is implicated in the pathogenesis, and inhibition of this pathway is a potential therapeutic strategy in FLNC-related cardiomyopathies.
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Affiliation(s)
- Suet Nee Chen
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Chi Keung Lam
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shanshan Gao
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Olfat A. Malak
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Shane Rui Zhao
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Raffaella Lombardi
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
- Department of Advanced Biomedical Sciences University of Naples “Federico II”, Naples, Italy
| | - Amrut V. Ambardekar
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Michael R. Bristow
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Joseph Cleveland
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Marta Gigli
- Cardiovascular Department, Azienda Sanitaria-Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Gianfranco Sinagra
- Cardiovascular Department, Azienda Sanitaria-Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Sharon Graw
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Matthew R.G. Taylor
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
| | - Joseph C. Wu
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Luisa Mestroni
- University of Colorado Cardiovascular Institute, University of Colorado Anschutz Medical Aurora, CO, USA
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11
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Ivanovic E, Kucera JP. Localization of Na + channel clusters in narrowed perinexi of gap junctions enhances cardiac impulse transmission via ephaptic coupling: a model study. J Physiol 2021; 599:4779-4811. [PMID: 34533834 PMCID: PMC9293295 DOI: 10.1113/jp282105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/06/2021] [Indexed: 01/06/2023] Open
Abstract
Abstract It has been proposed that when gap junctional coupling is reduced in cardiac tissue, action potential propagation can be supported via ephaptic coupling, a mechanism mediated by negative electric potentials occurring in narrow intercellular clefts of intercalated discs (IDs). Recent studies showed that sodium (Na+) channels form clusters near gap junction plaques in nanodomains called perinexi, where the ID cleft is even narrower. To examine the electrophysiological relevance of Na+ channel clusters being located in perinexi, we developed a 3D finite element model of two longitudinally abutting cardiomyocytes, with a central Na+ channel cluster on the ID membranes. When this cluster was located in the perinexus of a closely positioned gap junction plaque, varying perinexal width greatly modulated impulse transmission from one cell to the other, with narrow perinexi potentiating ephaptic coupling. This modulation occurred via the interplay of Na+ currents, extracellular potentials in the cleft and patterns of current flow within the cleft. In contrast, when the Na+ channel cluster was located remotely from the gap junction plaque, this modulation by perinexus width largely disappeared. Interestingly, the Na+ current in the ID membrane of the pre‐junctional cell switched from inward to outward during excitation, thus contributing ions to the activating channels on the post‐junctional ID membrane. In conclusion, these results indicate that the localization of Na+ channel clusters in the perinexi of gap junction plaques is crucial for ephaptic coupling, which is furthermore greatly modulated by perinexal width. These findings are relevant for a comprehensive understanding of cardiac excitation. Key points Ephaptic coupling is a cardiac conduction mechanism involving nanoscale‐level interactions between the sodium (Na+) current and the extracellular potential in narrow intercalated disc clefts. When gap junctional coupling is reduced, ephaptic coupling acts in conjunction with the classical cardiac conduction mechanism based on gap junctional current flow. In intercalated discs, Na+ channels form clusters that are preferentially located in the periphery of gap junction plaques, in nanodomains known as perinexi, but the electrophysiological role of these perinexi has never been examined. In our new 3D finite element model of two cardiac cells abutting each other with their intercalated discs, a Na+ channel cluster located inside a narrowed perinexus facilitated impulse transmission via ephaptic coupling. Our simulations demonstrate the role of narrowed perinexi as privileged sites for ephaptic coupling in pathological situations when gap junctional coupling is decreased.
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Affiliation(s)
- Ena Ivanovic
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bern, Switzerland
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12
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Jost N, Christ T, Magyar J. New Strategies for the Treatment of Atrial Fibrillation. Pharmaceuticals (Basel) 2021; 14:ph14090926. [PMID: 34577626 PMCID: PMC8466466 DOI: 10.3390/ph14090926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the clinical practice. It significantly contributes to the morbidity and mortality of the elderly population. Over the past 25-30 years intense effort in basic research has advanced the understanding of the relationship between the pathophysiology of AF and atrial remodelling. Nowadays it is clear that the various forms of atrial remodelling (electrical, contractile and structural) play crucial role in initiating and maintaining the persistent and permanent types of AF. Unlike in ventricular fibrillation, in AF rapid ectopic firing originating from pulmonary veins and re-entry mechanism may induce and maintain (due to atrial remodelling) this complex cardiac arrhythmia. The present review presents and discusses in detail the latest knowledge on the role of remodelling in AF. Special attention is paid to novel concepts and pharmacological targets presumably relevant to the drug treatment of atrial fibrillation.
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Affiliation(s)
- Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6725 Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6725 Szeged, Hungary
- Correspondence:
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
- Department of Sport Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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13
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Kléber AG, Jin Q. Coupling between cardiac cells-An important determinant of electrical impulse propagation and arrhythmogenesis. ACTA ACUST UNITED AC 2021; 2:031301. [PMID: 34296210 DOI: 10.1063/5.0050192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/09/2021] [Indexed: 01/30/2023]
Abstract
Cardiac arrhythmias are an important cause of sudden cardiac death-a devastating manifestation of many underlying causes, such as heart failure and ischemic heart disease leading to ventricular tachyarrhythmias and ventricular fibrillation, and atrial fibrillation causing cerebral embolism. Cardiac electrical propagation is a main factor in the initiation and maintenance of cardiac arrhythmias. In the heart, gap junctions are the basic unit at the cellular level that host intercellular low-resistance channels for the diffusion of ions and small regulatory molecules. The dual voltage clamp technique enabled the direct measurement of electrical conductance between cells and recording of single gap junction channel openings. The rapid turnover of gap junction channels at the intercalated disk implicates a highly dynamic process of trafficking and internalization of gap junction connexons. Recently, non-canonical roles of gap junction proteins have been discovered in mitochondria function, cytoskeletal organization, trafficking, and cardiac rescue. At the tissue level, we explain the concepts of linear propagation and safety factor based on the model of linear cellular structure. Working myocardium is adequately represented as a discontinuous cellular network characterized by cellular anisotropy and connective tissue heterogeneity. Electrical propagation in discontinuous cellular networks reflects an interplay of three main factors: cell-to-cell electrical coupling, flow of electrical charge through the ion channels, and the microscopic tissue structure. This review provides a state-of-the-art update of the cardiac gap junction channels and their role in cardiac electrical impulse propagation and highlights a combined approach of genetics, cell biology, and physics in modern cardiac electrophysiology.
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Affiliation(s)
- André G Kléber
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Qianru Jin
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, Massachusetts 02134, USA
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14
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Pourtaji A, Sahebkar A, Poorzand H, Moshiri M, Mohammadpour AH, Mousavi SR. Evaluation of the Cardioprotective Effect of Granulocyte Colony Stimulating Factor in Patients with Carbon Monoxide Poisoning. Protein Pept Lett 2021; 28:589-601. [PMID: 33092501 DOI: 10.2174/0929866527666201022112810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Carbon monoxide (CO), which is well known as silent killer, has many toxic effects on organs with high rate of metabolism such as heart and brain. CO-induced cardiotoxicity resulted in a wide range of disabilities including electrocardiogram (ECG) abnormalities, elevation in level of cardiac enzymes, arrhythmias, impairment of left ventricular and myocardial infarction (MI). Cardio-protective effects of Granulocyte colony-stimulating factor (G-CSF) on infarcted heart was proved previously in various reports. OBJECTIVE In this study, possible effect of G-CSF on cardiac function of patients with moderate to severe acute CO poisoning was investigated. METHODS Cardioprotective effects of G-CSF in CO-poisoned patients was evaluated through ECG, Holter monitoring, echocardiography, and biochemical studies. Continuous intravenous infusion of G-CSF (90 μg/kg) and normal saline were administered respectively to treatment and placebo groups. RESULTS The results demonstrated that in moderate to severe CO poisoning, myocardial injury is common. ECG changes (e.g., ST-segment and T-wave changes, QTC), cardiac arrhythmias (e.g., heart blocks and ventricular arrhythmias), serum level of Troponin I, left ventricular ejection fraction were determined after G-CSF administration. Frequencies of ST depression, inversion or flatting of T wave and QTC in ECG were significantly reduced after G-CSF treatment. In addition, incidence of cardiac arrhythmias due to CO poisoning were reduced after G-CSF treatment. However, G-CSF did not exert protective effects on TPI level and function of left ventricular in CO-poisoned patients. CONCLUSION GCSF could probably reduce CO-induced cardiac ischemia in patients with acute CO poisoning. CLINICAL TRIAL REGISTRATION The trial protocol was registered in the Iranian Registry of Clinical Trials (http://www.irct.ir) registry (Irct ID: IRCT201607232083N7).
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Affiliation(s)
- Atena Pourtaji
- Pharmaceutical Research Center, Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hoorak Poorzand
- Atherosclerosis Prevention Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Moshiri
- Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Hooshang Mohammadpour
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Reza Mousavi
- Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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15
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Kornej J, Hanger VA, Trinquart L, Ko D, Preis SR, Benjamin EJ, Lin H. New biomarkers from multiomics approaches: improving risk prediction of atrial fibrillation. Cardiovasc Res 2021; 117:1632-1644. [PMID: 33751041 PMCID: PMC8208748 DOI: 10.1093/cvr/cvab073] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/07/2021] [Accepted: 03/03/2021] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is a common cardiac arrhythmia leading to many adverse outcomes and increased mortality. Yet the molecular mechanisms underlying AF remain largely unknown. Recent advances in high-throughput technologies make large-scale molecular profiling possible. In the past decade, multiomics studies of AF have identified a number of potential biomarkers of AF. In this review, we focus on the studies of multiomics profiles with AF risk. We summarize recent advances in the discovery of novel biomarkers for AF through multiomics studies. We also discuss limitations and future directions in risk assessment and discovery of therapeutic targets for AF.
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Affiliation(s)
- Jelena Kornej
- National Heart, Lung, and Blood Institute’s Framingham Heart Study, 73 Mt Wayte Ave, Framingham, MA 01702, USA
- Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | | | - Ludovic Trinquart
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Darae Ko
- Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Sarah R Preis
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Emelia J Benjamin
- National Heart, Lung, and Blood Institute’s Framingham Heart Study, 73 Mt Wayte Ave, Framingham, MA 01702, USA
- Section of Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
- Section of Preventive Medicine & Epidemiology, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
| | - Honghuang Lin
- National Heart, Lung, and Blood Institute’s Framingham Heart Study, 73 Mt Wayte Ave, Framingham, MA 01702, USA
- Section of Computational Biomedicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
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16
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Fu YL, Tao L, Peng FH, Zheng NZ, Lin Q, Cai SY, Wang Q. GJA1-20k attenuates Ang II-induced pathological cardiac hypertrophy by regulating gap junction formation and mitochondrial function. Acta Pharmacol Sin 2021; 42:536-549. [PMID: 32620936 PMCID: PMC8115281 DOI: 10.1038/s41401-020-0459-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/07/2020] [Indexed: 02/06/2023] Open
Abstract
Cardiac hypertrophy (CH) is characterized by an increase in cardiomyocyte size, and is the most common cause of cardiac-related sudden death. A decrease in gap junction (GJ) coupling and mitochondrial dysfunction are important features of CH, but the mechanisms of decreased coupling and energy impairment are poorly understood. It has been reported that GJA1-20k has a strong tropism for mitochondria and is required for the trafficking of connexin 43 (Cx43) to cell-cell borders. In this study, we investigated the effects of GJA1-20k on Cx43 GJ coupling and mitochondrial function in the pathogenesis of CH. We performed hematoxylin-eosin (HE) and Masson staining, and observed significant CH in 18-week-old male spontaneously hypertensive rats (SHRs) compared to age-matched normotensive Wistar-Kyoto (WKY) rats. In cardiomyocytes from SHRs, the levels of Cx43 at the intercalated disc (ID) and the expression of GJA1-20k were significantly reduced, whereas JAK-STAT signaling was activated. Furthermore, the SHR rats displayed suppressed mitochondrial GJA1-20k and mitochondrial biogenesis. Administration of valsartan (10 mg· [Formula: see text] d-1, i.g., for 8 weeks) prevented all of these changes. In neonatal rat cardiomyocytes (NRCMs), overexpression of GJA1-20k attenuated Ang II-induced cardiomyocyte hypertrophy and caused elevated levels of GJ coupling at the cell-cell borders. Pretreatment of NRCMs with the Jak2 inhibitor AG490 (10 µM) blocked Ang II-induced reduction in GJA1-20k expression and Cx43 gap junction formation; knockdown of Jak2 in NRCMs significantly lessened Ang II-induced cardiomyocyte hypertrophy and normalized GJA1-20k expression and Cx43 gap junction formation. Overexpression of GJA1-20k improved mitochondrial membrane potential and respiration and lowered ROS production in Ang II-induced cardiomyocyte hypertrophy. These results demonstrate the importance of GJA1-20k in regulating gap junction formation and mitochondrial function in Ang II-induced cardiomyocyte hypertrophy, thus providing a novel therapeutic strategy for patients with cardiomyocyte hypertrophy.
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Affiliation(s)
- Yi-le Fu
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Liang Tao
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Fu-Hua Peng
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Ning-Ze Zheng
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Qing Lin
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Shao-Yi Cai
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Qin Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China.
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17
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Andelova K, Egan Benova T, Szeiffova Bacova B, Sykora M, Prado NJ, Diez ER, Hlivak P, Tribulova N. Cardiac Connexin-43 Hemichannels and Pannexin1 Channels: Provocative Antiarrhythmic Targets. Int J Mol Sci 2020; 22:ijms22010260. [PMID: 33383853 PMCID: PMC7795512 DOI: 10.3390/ijms22010260] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac connexin-43 (Cx43) creates gap junction channels (GJCs) at intercellular contacts and hemi-channels (HCs) at the peri-junctional plasma membrane and sarcolemmal caveolae/rafts compartments. GJCs are fundamental for the direct cardiac cell-to-cell transmission of electrical and molecular signals which ensures synchronous myocardial contraction. The HCs and structurally similar pannexin1 (Panx1) channels are active in stressful conditions. These channels are essential for paracrine and autocrine communication through the release of ions and signaling molecules to the extracellular environment, or for uptake from it. The HCs and Panx1 channel-opening profoundly affects intracellular ionic homeostasis and redox status and facilitates via purinergic signaling pro-inflammatory and pro-fibrotic processes. These conditions promote cardiac arrhythmogenesis due to the impairment of the GJCs and selective ion channel function. Crosstalk between GJCs and HCs/Panx1 channels could be crucial in the development of arrhythmogenic substrates, including fibrosis. Despite the knowledge gap in the regulation of these channels, current evidence indicates that HCs and Panx1 channel activation can enhance the risk of cardiac arrhythmias. It is extremely challenging to target HCs and Panx1 channels by inhibitory agents to hamper development of cardiac rhythm disorders. Progress in this field may contribute to novel therapeutic approaches for patients prone to develop atrial or ventricular fibrillation.
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Affiliation(s)
- Katarina Andelova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Tamara Egan Benova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Barbara Szeiffova Bacova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Matus Sykora
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Natalia Jorgelina Prado
- Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, M5500 Mendoza, Argentina; (N.J.P.); (E.R.D.)
| | - Emiliano Raul Diez
- Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, M5500 Mendoza, Argentina; (N.J.P.); (E.R.D.)
| | - Peter Hlivak
- Department of Arrhythmias and Pacing, National Institute of Cardiovascular Diseases, Pod Krásnou Hôrkou 1, 83348 Bratislava, Slovakia;
| | - Narcis Tribulova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
- Correspondence: ; Tel.: +421-2-32295-423
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18
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Wang J, Fan Y, Cai X, Gao Z, Yu Z, Wei B, Tang Y, Hu L, Liu WT, Gu Y. Uric acid preconditioning alleviated doxorubicin induced JNK activation and Cx43 phosphorylation associated cardiotoxicity via activation of AMPK-SHP2 signaling pathway. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1570. [PMID: 33437769 PMCID: PMC7791217 DOI: 10.21037/atm-20-3105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Doxorubicin is an anthracycline antibiotic, which is effective for treating various malignancies such as leukemias and lymphomas. However, its serious cumulative dose-dependent cardiotoxicity limits its clinical application. Previous studies have shown that doxorubicin-associated cardiotoxicity is closely related to adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK). Uric acid is known to exert a strong antioxidant function and moderate protection on the nerves. However, its cardioprotective properties have not been established. This study aimed to investigate the potential effect of uric acid preconditioning on doxorubicin-induced cardiotoxicity and the involvement of AMPK signaling in this process. Methods An acute cardiotoxicity model of doxorubicin was established by intraperitoneal injection of a single dose of doxorubicin (20 mg/kg) in mice. Uric acid (62.5, 125, and 250 mg/kg) was intragastrically administered to mice one day before doxorubicin treatment and then continuously administered every 24 h for 8 consecutive days. The mortality rate and weight of the mice were recorded every day. Electrocardiograms (ECG) and serum biochemicals were detected with an ECG instrument and enzyme-linked immunosorbent assay kit (Elisa) respectively. A real-time cell analyzer (RTCA) was used to investigate the cytotoxicity of doxorubicin in vitro. Cell signaling was assayed by western blotting. Results Uric acid (125 mg/kg) preconditioning increased the survival rate and body weight of doxorubicin-treated mice. Uric acid also effectively alleviated prolongation of the doxorubicin-induced QT interval, slowed heart rate, and reduced the plasma levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) in plasma in mice. Moreover, uric acid strongly activated AMPK and Src homology 2 domain-containing protein tyrosine phosphatase (SHP2), inhibiting doxorubicin-induced expression phosphorylated-c-Jun N-terminal kinases (JNK) and phosphorylated-connexin 43 (Cx43) in vitro and in vivo and effectively reversing the doxorubicin-induced decreased viability of H9C2 myocardial cells in vitro. Conclusions We demonstrated that uric acid preconditioning alleviated doxorubicin-induced cardiotoxicity through the AMPK-SHP2-JNK-Cx43 signaling pathway.
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Affiliation(s)
- Jiawei Wang
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yixin Fan
- Department of Pharmacy, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Xiaomin Cai
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhenzhen Gao
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhengyi Yu
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Bin Wei
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yulin Tang
- Department of Pharmacy, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Liang Hu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Wen-Tao Liu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Yanhong Gu
- Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Zheng L, Trease AJ, Katsurada K, Spagnol G, Li H, Shi W, Duan B, Patel KP, Sorgen PL. Inhibition of Pyk2 and Src activity improves Cx43 gap junction intercellular communication. J Mol Cell Cardiol 2020; 149:27-40. [PMID: 32956670 DOI: 10.1016/j.yjmcc.2020.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 11/24/2022]
Abstract
Identification of proteins that interact with Cx43 has been instrumental in the understanding of gap junction (GJ) regulation. An in vitro phosphorylation screen identified that Protein tyrosine kinase 2 beta (Pyk2) phosphorylated purified Cx43CT and this led us to characterize the impact of this phosphorylation on Cx43 function. Mass spectrometry identified Pyk2 phosphorylates Cx43 residues Y247, Y265, Y267, and Y313. Western blot and immunofluorescence staining using HeLaCx43 cells, HEK 293 T cells, and neonatal rat ventricular myocytes (NRVMs) revealed Pyk2 can be activated by Src and active Pyk2 interacts with Cx43 at the plasma membrane. Overexpression of Pyk2 increases Cx43 phosphorylation and knock-down of Pyk2 decreases Cx43 phosphorylation, without affecting the level of active Src. In HeLaCx43 cells treated with PMA to activate Pyk2, a decrease in Cx43 GJ intercellular communication (GJIC) was observed when assayed by dye transfer. Moreover, PMA activation of Pyk2 could be inhibited by the small molecule PF4618433. This partially restored GJIC, and when paired with a Src inhibitor, returned GJIC to the no PMA control-level. The ability of Pyk2 and Src inhibitors to restore Cx43 function in the presence of PMA was also observed in NRVMs. Additionally, an animal model of myocardial infarction induced heart failure showed a higher level of active Pyk2 activity and increased interaction with Cx43 in ventricular myocytes. Src inhibitors have been used to reverse Cx43 remodeling and improve heart function after myocardial infarction; however, they alone could not fully restore proper Cx43 function. Our data suggest that Pyk2 may need to be inhibited, in addition to Src, to further (if not completely) reverse Cx43 remodeling and improve intercellular communication.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wen Shi
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bin Duan
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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20
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Macquart C, Jüttner R, Morales Rodriguez B, Le Dour C, Lefebvre F, Chatzifrangkeskou M, Schmitt A, Gotthardt M, Bonne G, Muchir A. Microtubule cytoskeleton regulates Connexin 43 localization and cardiac conduction in cardiomyopathy caused by mutation in A-type lamins gene. Hum Mol Genet 2020; 28:4043-4052. [PMID: 29893868 DOI: 10.1093/hmg/ddy227] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/05/2018] [Accepted: 06/06/2018] [Indexed: 01/08/2023] Open
Abstract
Mutations in the lamin A/C gene (LMNA) cause an autosomal dominant inherited form of dilated cardiomyopathy associated with cardiac conduction disease (hereafter referred to as LMNA cardiomyopathy). Compared with other forms of dilated cardiomyopathy, mutations in LMNA are responsible for a more aggressive clinical course owing to a high rate of malignant ventricular arrhythmias. Gap junctions are intercellular channels that allow direct communication between neighboring cells, which are involved in electrical impulse propagation and coordinated contraction of the heart. For gap junctions to properly control electrical synchronization in the heart, connexin-based hemichannels must be correctly targeted to intercalated discs, Cx43 being the major connexin in the working myocytes. We here showed an altered distribution of Cx43 in a mouse model of LMNA cardiomyopathy. However, little is known on the molecular mechanisms of Cx43 remodeling in pathological context. We now show that microtubule cytoskeleton alteration and decreased acetylation of α-tubulin lead to remodeling of Cx43 in LMNA cardiomyopathy, which alters the correct communication between cardiomyocytes, ultimately leading to electrical conduction disturbances. Preventing or reversing this process could offer a strategy to repair damaged heart. Stabilization of microtubule cytoskeleton using Paclitaxel improved intraventricular conduction defects. These results indicate that microtubule cytoskeleton contributes to the pathogenesis of LMNA cardiomyopathy and that drugs stabilizing the microtubule may be beneficial for patients.
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Affiliation(s)
- Coline Macquart
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris 75013, France
| | - Rene Jüttner
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris 75013, France
| | - Caroline Le Dour
- Department of Medicine.,Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Florence Lefebvre
- Signaling and Cardiovascular Pathophysiology, UMRS 1180, Université Paris-Sud, INSERM, Chatenay-Malabry 92216, France
| | - Maria Chatzifrangkeskou
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris 75013, France
| | - Alain Schmitt
- Institut Cochin, INSERM U1016-CNRS UMR 8104, Université Paris Descartes-Sorbonne Paris Cité, Paris F-75014, France
| | - Michael Gotthardt
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany.,Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13092 Berlin, Germany
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris 75013, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, Paris 75013, France
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21
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Li J, Li B, Bai F, Ma Y, Liu N, Liu Y, Wang Y, Liu Q. Metformin therapy confers cardioprotection against the remodeling of gap junction in tachycardia-induced atrial fibrillation dog model. Life Sci 2020; 254:117759. [PMID: 32389830 DOI: 10.1016/j.lfs.2020.117759] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 04/23/2020] [Accepted: 05/04/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Metformin, introduced in 1957, is widely used as an anti-diabetic drug and has considerable benefits in cardiovascular disease reportedly, dependent or independent on its glucose-lowering effects. Aim of this study was to investigate the effect of metformin on gap junction and the inducibility of AF. METHODS Beagle dogs were subjected to acute or chronic pacing at right atrial appendage by a pacemaker to develop an AF model and electrophysiological parameters were measured. In vitro study, a cell fast pacing model was developed by CardioExcyte 96. We performed Western blot, histology immunohistochemical staining and electron microscopy to detect the effect of metformin. RESULTS In chronic AF model, the inducibility and duration of AF increased obviously after pacing for 6 weeks compared with sham-operated group (Inducibility, 3.33 ± 5.77 vs. 85.33 ± 7.89%, P<0.0001; Duration, 0.8 ± 0.84 vs. 11 ± 2.67 ms, P<0.0001). Effective refractory periods (ERP) decreased at left and right left atrium and atrial appendages compared with sham-operated group (123.95 ± 6.57 vs. 89.96 ± 7.39 ms P<0.0001). Metformin attenuated the pacing-induced increase in EPR (89.96 ± 7.39 vs. 105.83 ± 7.45 ms, P<0.05), AF inducibility and AF duration (Inducibility, 85.33 ± 7.89 vs. 64.17 ± 7.36%, Duration, 11 ± 2.67 vs. 8.62 ± 1.15 ms, P<0.05). The expression of Cx43 shows a significant downregulation(about 38%, P<0.001) after chronic pacing and treating with metformin could alleviate this decrease(P<0.01). However, the effect of metformin in acute pacing model is limited. The immunohistochemical staining of cardiac tissue also shown that there is more lateralized Cx43 under pacing condition (87.67 ± 2.52 vs. 60.8 ± 9.13%, P<0.005). These pacing-induced lateralize Cx43 could be alleviated by the metformin (48.4 ± 8.62 vs. 60.8 ± 9.13%, P<0.05). Additionally, metformin could affect the interactions of ZO-1 with p-Src/Cx43 via decrease the abnormal cAMP level after pacing (84.04 ± 4.58 vs. 69.34 ± 4.5 nmol/L, P<0.001). CONCLUSIONS Metformin could alleviate the vulnerability of AF and attenuate the downregulation of gap junction under pacing condition via AMPK pathway and decreasing the P-Src level.
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Affiliation(s)
- Jiayi Li
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Biao Li
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Fan Bai
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yinxu Ma
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Na Liu
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yaozhong Liu
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yibo Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qiming Liu
- Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
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22
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Basheer WA, Fu Y, Shimura D, Xiao S, Agvanian S, Hernandez DM, Hitzeman TC, Hong T, Shaw RM. Stress response protein GJA1-20k promotes mitochondrial biogenesis, metabolic quiescence, and cardioprotection against ischemia/reperfusion injury. JCI Insight 2018; 3:121900. [PMID: 30333316 DOI: 10.1172/jci.insight.121900] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/11/2018] [Indexed: 01/23/2023] Open
Abstract
Connexin 43 (Cx43), a product of the GJA1 gene, is a gap junction protein facilitating intercellular communication between cardiomyocytes. Cx43 protects the heart from ischemic injury by mechanisms that are not well understood. GJA1 mRNA can undergo alternative translation, generating smaller isoforms in the heart, with GJA1-20k being the most abundant. Here, we report that ischemic and ischemia/reperfusion (I/R) injuries upregulate endogenous GJA1-20k protein in the heart, which targets to cardiac mitochondria and associates with the outer mitochondrial membrane. Exploring the functional consequence of increased GJA1-20k, we found that AAV9-mediated gene transfer of GJA1-20k in mouse hearts increases mitochondrial biogenesis while reducing mitochondrial membrane potential, respiration, and ROS production. By doing so, GJA1-20k promotes a protective mitochondrial phenotype, as seen with ischemic preconditioning (IPC), which also increases endogenous GJA1-20k in heart lysates and mitochondrial fractions. As a result, AAV9-GJA1-20k pretreatment reduces myocardial infarct size in mouse hearts subjected to in vivo ischemic injury or ex vivo I/R injury, similar to an IPC-induced cardioprotective effect. In conclusion, GJA1-20k is an endogenous stress response protein that induces mitochondrial biogenesis and metabolic hibernation, preconditioning the heart against I/R insults. Introduction of exogenous GJA1-20k is a putative therapeutic strategy for patients undergoing anticipated ischemic injury.
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Affiliation(s)
- Wassim A Basheer
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ying Fu
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Daisuke Shimura
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Shaohua Xiao
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Sosse Agvanian
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Diana M Hernandez
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Tara C Hitzeman
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - TingTing Hong
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, California
| | - Robin M Shaw
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, California
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23
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Long non-coding RNA CCRR controls cardiac conduction via regulating intercellular coupling. Nat Commun 2018; 9:4176. [PMID: 30301979 PMCID: PMC6177441 DOI: 10.1038/s41467-018-06637-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 09/10/2018] [Indexed: 12/31/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) have emerged as a new class of gene expression regulators playing key roles in many biological and pathophysiological processes. Here, we identify cardiac conduction regulatory RNA (CCRR) as an antiarrhythmic lncRNA. CCRR is downregulated in a mouse model of heart failure (HF) and in patients with HF, and this downregulation slows cardiac conduction and enhances arrhythmogenicity. Moreover, CCRR silencing induces arrhythmias in healthy mice. CCRR overexpression eliminates these detrimental alterations. HF or CCRR knockdown causes destruction of intercalated discs and gap junctions to slow longitudinal cardiac conduction. CCRR overexpression improves cardiac conduction by blocking endocytic trafficking of connexin43 (Cx43) to prevent its degradation via binding to Cx43-interacting protein CIP85, whereas CCRR silence does the opposite. We identified the functional domain of CCRR, which can reproduce the functional roles and pertinent molecular events of full-length CCRR. Our study suggests CCRR replacement a potential therapeutic approach for pathological arrhythmias.
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24
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Wörsdörfer P, Wagner N, Ergün S. The role of connexins during early embryonic development: pluripotent stem cells, gene editing, and artificial embryonic tissues as tools to close the knowledge gap. Histochem Cell Biol 2018; 150:327-339. [PMID: 30039329 DOI: 10.1007/s00418-018-1697-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2018] [Indexed: 12/14/2022]
Abstract
Since almost 4 decades, connexins have been discussed as important regulators of embryogenesis. Several different members of the gene family can be detected in the preimplantation embryo and during gastrulation. However, genetically engineered mice deficient for every connexin expressed during early development are available and even double-deficient mice were generated. Interestingly, all of these mice complete gastrulation without any abnormalities. This raises the question if the role of connexins has been overrated or if other gene family members compensate and mask their importance. To answer this question, embryos completely devoid of any gap junctional communication need to be investigated. This is challenging because a variety of connexin genes are co-expressed and some null mutations lead to a lethal phenotype. In addition, maternal connexin transcripts were described to persist until the blastocyst stage. In this review, we summarize the current knowledge about the role of connexins during preimplantation development and in embryonic stem cells. We propose that the use of pluripotent stem cells, trophoblast stem cells, as well as artificial embryo-like structures and organoid cultures in combination with multiplex CRISPR/Cas9-based genome editing provides a powerful platform to comprehensively readdress this issue and decipher the role of connexins during lineage decision, differentiation, and morphogenesis in a cell culture model for mouse and human development.
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Affiliation(s)
- Philipp Wörsdörfer
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr.6, 97070, Würzburg, Germany.
| | - Nicole Wagner
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr.6, 97070, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr.6, 97070, Würzburg, Germany
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25
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Basheer WA, Shaw RM. Connexin 43 and CaV1.2 Ion Channel Trafficking in Healthy and Diseased Myocardium. Circ Arrhythm Electrophysiol 2018; 9:e001357. [PMID: 27266274 DOI: 10.1161/circep.115.001357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/29/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Wassim A Basheer
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.).
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26
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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Epifantseva I, Shaw RM. Intracellular trafficking pathways of Cx43 gap junction channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:40-47. [PMID: 28576298 DOI: 10.1016/j.bbamem.2017.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/11/2022]
Abstract
Gap Junction (GJ) channels, including the most common Connexin 43 (Cx43), have fundamental roles in excitable tissues by facilitating rapid transmission of action potentials between adjacent cells. For instance, synchronization during each heartbeat is regulated by these ion channels at the cardiomyocyte cell-cell border. Cx43 protein has a short half-life, and rapid synthesis and timely delivery of those proteins to particular subdomains are crucial for the cellular organization of gap junctions and maintenance of intracellular coupling. Impairment in gap junction trafficking contributes to dangerous complications in diseased hearts such as the arrhythmias of sudden cardiac death. Of recent interest are the protein-protein interactions with the Cx43 carboxy-terminus. These interactions have significant impact on the full length Cx43 lifecycle and also contribute to trafficking of Cx43 as well as possibly other functions. We are learning that many of the known non-canonical roles of Cx43 can be attributed to the recently identified six endogenous Cx43 truncated isoforms which are produced by internal translation. In general, alternative translation is a new leading edge for proteome expansion and therapeutic drug development. This review highlights recent mechanisms identified in the trafficking of gap junction channels, involvement of other proteins contributing to the delivery of channels to the cell-cell border, and understanding of possible roles of the newly discovered alternatively translated isoforms in Cx43 biology. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Irina Epifantseva
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.; Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA..
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George SA, Calhoun PJ, Gourdie RG, Smyth JW, Poelzing S. TNFα Modulates Cardiac Conduction by Altering Electrical Coupling between Myocytes. Front Physiol 2017; 8:334. [PMID: 28588504 PMCID: PMC5440594 DOI: 10.3389/fphys.2017.00334] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Background: Tumor Necrosis Factor α (TNFα) upregulation during acute inflammatory response has been associated with numerous cardiac effects including modulating Connexin43 and vascular permeability. This may in turn alter cardiac gap junctional (GJ) coupling and extracellular volume (ephaptic coupling) respectively. We hypothesized that acute exposure to pathophysiological TNFα levels can modulate conduction velocity (CV) in the heart by altering electrical coupling: GJ and ephaptic. Methods and Results: Hearts were optically mapped to determine CV from control, TNFα and TNFα + high calcium (2.5 vs. 1.25 mM) treated guinea pig hearts over 90 mins. Transmission electron microscopy was performed to measure changes in intercellular separation in the gap junction-adjacent extracellular nanodomain—perinexus (WP). Cx43 expression and phosphorylation were determined by Western blotting and Cx43 distribution by confocal immunofluorescence. At 90 mins, longitudinal and transverse CV (CVL and CVT, respectively) increased with control Tyrode perfusion but TNFα slowed CVT alone relative to control and anisotropy of conduction increased, but not significantly. TNFα increased WP relative to control at 90 mins, without significantly changing GJ coupling. Increasing extracellular calcium after 30 mins of just TNFα exposure increased CVT within 15 mins. TNFα + high calcium also restored CVT at 90 mins and reduced WP to control values. Interestingly, TNFα + high calcium also improved GJ coupling at 90 mins, which along with reduced WP may have contributed to increasing CV. Conclusions: Elevating extracellular calcium during acute TNFα exposure reduces perinexal expansion, increases ephaptic, and GJ coupling, improves CV and may be a novel method for preventing inflammation induced CV slowing.
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Affiliation(s)
- Sharon A George
- Department of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State UniversityBlacksburg, VA, United States
| | - Patrick J Calhoun
- Department of Biological Sciences, Virginia Polytechnic Institute and State UniversityBlacksburg, VA, United States
| | - Robert G Gourdie
- Department of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State UniversityBlacksburg, VA, United States.,Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research InstituteRoanoke, VA, United States
| | - James W Smyth
- Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research InstituteRoanoke, VA, United States
| | - Steven Poelzing
- Department of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State UniversityBlacksburg, VA, United States.,Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research InstituteRoanoke, VA, United States
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Petersen F, Rodrigo R, Richter M, Kostin S. The effects of polyunsaturated fatty acids and antioxidant vitamins on atrial oxidative stress, nitrotyrosine residues, and connexins following extracorporeal circulation in patients undergoing cardiac surgery. Mol Cell Biochem 2017; 433:27-40. [DOI: 10.1007/s11010-017-3013-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/15/2017] [Indexed: 12/27/2022]
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Wu Q, Wu Y, Zhang L, Zheng J, Tang S, Cheng J. GJA1 gene variations in sudden unexplained nocturnal death syndrome in the Chinese Han population. Forensic Sci Int 2016; 270:178-182. [PMID: 27992820 DOI: 10.1016/j.forsciint.2016.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/09/2016] [Accepted: 12/03/2016] [Indexed: 10/20/2022]
Abstract
Sudden unexplained nocturnal death syndrome (SUNDS) is a conundrum to both forensic pathologists and physicians, more than 80% of which the molecular pathogenesis remains unclear. Reported studies on both clinical and genetic phenotypes suggest SUNDS is related to congenital and acquired arrhythmias. Recent researches have linked the mutations of gene gap junction alpha 1 (GJA1) with arrhythmogenic cardiac disorders. In the present study, we investigate the potential correlation between GJA1 gene variations and the occurrence of SUNDS. Genomic DNA was extracted from the blood samples of both 124 sporadic SUNDS patients and 125 healthy controls to screen GJA1 gene for candidate variants using polymerase chain reaction (PCR) and direct DNA sequencing. One novel homozygous variant c.169C>T and one heterozygous SNP c.624C>T (rs530633057) were determined in 124 SUNDS cases (one case for each detected variant) and none of the 125 healthy controls. Base C>T transition at nucleotide position 169 led to termination of protein production after glutamine (Q) at codon 57 which is very likely to result in decreased expression of Cx43 gap junction channels and cause arrhythmic sudden death. This is the first report of GJA1 gene variations in SUNDS in the Chinese Han population, which suggests a novel susceptibility gene for Chinese SUNDS.
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Affiliation(s)
- Qiuping Wu
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Yeda Wu
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Liyong Zhang
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Jinxiang Zheng
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Shuangbo Tang
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Jianding Cheng
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
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Wei N, Mori Y, Tolkacheva EG. The dual effect of ephaptic coupling on cardiac conduction with heterogeneous expression of connexin 43. J Theor Biol 2016; 397:103-14. [PMID: 26968493 DOI: 10.1016/j.jtbi.2016.02.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/25/2016] [Accepted: 02/19/2016] [Indexed: 11/30/2022]
Abstract
Decreased and heterogeneous expression of connexin 43 (Cx43) are common features in animal heart failure models. Ephpatic coupling, which relies on the presence of junctional cleft space between the ends of adjacent cells, has been suggested to play a more active role in mediating intercellular electrical communication when gap junctions are reduced. To better understand the interplay of Cx43 expression and ephaptic coupling on cardiac conduction during heart failure, we performed numerical simulations on our model when Cx43 expression is reduced and heterogeneous. Under severely reduced Cx43 expression, we identified three new phenomena in the presence of ephaptic coupling: alternating conduction, in which ephaptic and gap junction-mediated mechanisms alternate; instability of planar fronts; and small amplitude action potential (SAP), which has a smaller potential amplitude than the normal action potential. In the presence of heterogeneous Cx43 expression, ephaptic coupling can either prevent or promote conduction block (CB) depending on the Cx43 knockout (Cx43KO) content. When Cx43KO content is relatively high, ephaptic coupling reduces the probabilities of CB. However, ephaptic coupling promotes CB when Cx43KO and wild type cells are mixed in roughly equal proportion, which can be attributed to an increase in current-to-load mismatch.
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Affiliation(s)
- Ning Wei
- School of Mathematics, University of Minnesota, 206 Church St. SE, Minneapolis, MN 55455, United States
| | - Yoichiro Mori
- School of Mathematics, University of Minnesota, 206 Church St. SE, Minneapolis, MN 55455, United States
| | - Elena G Tolkacheva
- Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, 6-128 Nils Hasselmo Hall, Minneapolis, MN 55455, United States.
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Boulaksil M, Bierhuizen MFA, Engelen MA, Stein M, Kok BJM, van Amersfoorth SCM, Vos MA, van Rijen HVM, de Bakker JMT, van Veen TAB. Spatial Heterogeneity of Cx43 is an Arrhythmogenic Substrate of Polymorphic Ventricular Tachycardias during Compensated Cardiac Hypertrophy in Rats. Front Cardiovasc Med 2016; 3:5. [PMID: 26973841 PMCID: PMC4773605 DOI: 10.3389/fcvm.2016.00005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/18/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Ventricular remodeling increases the propensity of ventricular tachyarrhythmias and sudden death in patients. We studied the mechanism underlying these fatal arrhythmias, electrical and structural cardiac remodeling, as well as arrhythmogeneity during early, compensated hypertrophy in a rat model of chronic pressure overload. METHODS Twenty-six Wistar rats were subjected to transverse aortic constriction (TAC) (n = 13) or sham operation (n = 13). Four weeks postoperative, echo- and electrocardiography was performed. Epicardial (208 or 455 sites) and transmural (30 sites) ventricular activation mapping was performed on Langendorff perfused hearts. Subsequently, hearts were processed for (immuno)histological and molecular analyses. RESULTS TAC rats showed significant hypertrophy with preserved left ventricular (LV) function. Epicardial conduction velocity (CV) was similar, but more dispersed in TAC. Transmural CV was slowed in TAC (37.6 ± 2.9 cm s(-1)) compared to sham (58.5 ± 3.9 cm s(-1); P < 0.01). Sustained polymorphic ventricular tachycardias were induced from LV in 8/13 TAC and in 0/13 sham rats. During VT, electrical activation patterns showed variable sites of earliest epicardial activation and altering sites of functional conduction block. Wandering epicardial reentrant activation was sporadically observed. Collagen deposition was significantly higher in TAC compared to sham, but not different between arrhythmogenic and non-arrhythmogenic TAC animals. Connexin43 (Cx43) expression was heterogeneous with a higher prevalence of non-phosphorylated Cx43 in arrhythmogenic TAC animals. CONCLUSION In TAC rats with compensated cardiac hypertrophy, dispersion of conduction correlated to arrhythmogenesis, an increased heterogeneity of Cx43, and a partial substitution with non-phosphorylated Cx43. These alterations may result in the increased vulnerability to polymorphic VTs.
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Affiliation(s)
- Mohamed Boulaksil
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, Netherlands; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Department of Cardiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Marti F A Bierhuizen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Markus A Engelen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Division of Cardiology, Department of Cardiovascular Medicine, University of Muenster, Muenster, Germany
| | - Mèra Stein
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Division of Heart and Lungs, Department of Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bart J M Kok
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | | | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Harold V M van Rijen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Jacques M T de Bakker
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, Netherlands; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Heart Failure Research Center, Academic Medical Center, Amsterdam, Netherlands
| | - Toon A B van Veen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
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Zhao Q, Chen Y, Peng L, Gao R, Liu N, Jiang P, Liu C, Tang S, Quan L, Makielski JC, Cheng J. Identification of rare variants of DSP gene in sudden unexplained nocturnal death syndrome in the southern Chinese Han population. Int J Legal Med 2016; 130:317-22. [PMID: 26585738 PMCID: PMC4951159 DOI: 10.1007/s00414-015-1275-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/13/2015] [Indexed: 11/25/2022]
Abstract
Sudden unexplained nocturnal death syndrome (SUNDS) is a perplexing disorder to both forensic pathologists and clinic physicians. Desmoplakin (DSP) gene was the first desmosomal gene linked to arrhythmogenic right ventricular cardiomyopathy (ARVC) which was associated with sudden death. To identify the genetic variants of the DSP gene in SUNDS in the southern Chinese Han population, we genetically screened the DSP gene in 40 sporadic SUNDS victims, 16 Brugada syndrome (BrS) patients, and 2 early repolarization syndrome (ERS) patients using next generation sequencing (NSG) and direct Sanger sequencing. A total of 10 genetic variants of the DSP gene were detected in 11 cases, comprised of two novel missense mutations (p.I125F and p.D521A) and eight previously reported rare variants. Of eight reported variants, two were previously considered pathogenic (p.Q90R and p.R2639Q), three were predicted in silico to be pathogenic (p.R315C, p.E1357D and p.D2579H), and the rest three were predicted to be benign (p.N1234S, p.R1308Q, and p.T2267S). This is the first report of DSP genetic screening in Chinese SUNDS and Brugada syndrome. Our results imply that DSP mutations contribute to the genetic cause of some SUNDS victims and maybe a new susceptible gene for Brugada syndrome.
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Affiliation(s)
- Qianhao Zhao
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, No. 74, Zhongshan 2nd Road, Guangzhou, Guangdong, 510080, China
| | - Yili Chen
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Longlun Peng
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Rui Gao
- BGI-Shenzhen, Shenzhen, 518083, China
| | - Nian Liu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | | | - Chao Liu
- BGI-Shenzhen, Shenzhen, 518083, China
| | - Shuangbo Tang
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, No. 74, Zhongshan 2nd Road, Guangzhou, Guangdong, 510080, China
| | - Li Quan
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, No. 74, Zhongshan 2nd Road, Guangzhou, Guangdong, 510080, China.
| | - Jonathan C Makielski
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI, 53792, USA.
| | - Jianding Cheng
- Department of Forensic Pathology, Zhongshan School of Medicine, Sun Yat-sen University, No. 74, Zhongshan 2nd Road, Guangzhou, Guangdong, 510080, China.
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George SA, Poelzing S. Cardiac conduction in isolated hearts of genetically modified mice--Connexin43 and salts. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:189-98. [PMID: 26627143 DOI: 10.1016/j.pbiomolbio.2015.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/13/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
Abstract
Physiologic variations in perfusate composition have been identified as a new and important modulator of cardiac conduction velocity (CV), particularly when gap junctions (GJ) are reduced. We recently demonstrated in ex vivo hearts that perfusates with low sodium and high potassium preferentially slow ventricular CV in mice genetically engineered to express 50% less of the gap junction protein, connexin43 (Cx43). We also reported the possible role of calcium in modulating CV. In this review we discuss previous murine studies that explored the CV-GJ relationship in isolated mouse heart preparations with approximately 50% reduced Cx43. Studies were grouped according to the type of perfusate utilized, and CV during GJ uncoupling was compared. Studies in Group A preferentially used perfusates with low sodium, high potassium and non-physiologic calcium, and found CV slows and arrhythmias increase in mouse hearts with reduced Cx43. Studies in Group B used solutions with high sodium, low potassium and physiologic calcium, and did not observe CV slowing nor increased arrhythmia risk with loss of Cx3. Studies in Group C used solutions with low sodium, low potassium, physiologic calcium, creatine, taurine, and insulin. CV slowing was not observed, nor was arrhythmia risk increased with loss of Cx43. We suggest that perfusate ion composition may be a major determinant of whether CV slows when Cx43 is reduced. Furthermore, the review of these studies highlights important theoretical developments in the understanding of cardiac conduction and suggests that ionic milieu can conceal electrophysiologic remodeling secondary to reduced Cx43 expression as occurs in many cardiac diseases.
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Affiliation(s)
- Sharon A George
- Department of Biomedical Engineering and Mechanics, Virginia Tech Carilion Research Institute, and Center for Heart and Regenerative Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
| | - Steven Poelzing
- Department of Biomedical Engineering and Mechanics, Virginia Tech Carilion Research Institute, and Center for Heart and Regenerative Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
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35
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Basheer W, Shaw R. The "tail" of Connexin43: An unexpected journey from alternative translation to trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1848-56. [PMID: 26526689 DOI: 10.1016/j.bbamcr.2015.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
Abstract
With each heartbeat, Connexin43 (Cx43) cell-cell communication gap junctions are needed to rapidly spread and coordinate excitation signals for an effective heart contraction. The correct formation and delivery of channels to their respective membrane subdomain is referred to as protein trafficking. Altered Cx43 trafficking is a dangerous complication of diseased myocardium which contributes to the arrhythmias of sudden cardiac death. Cx43 has also been found to regulate many other cellular processes that cannot be explained by cell-cell communication. We recently identified the existence of up to six endogenous internally translated Cx43 N-terminal truncated isoforms from the same full-length mRNA molecule. This is the first evidence that alternative translation is possible for human ion channels and in human heart. Interestingly, we found that these internally translated isoforms, more specifically the 20 kDa isoform (GJA1-20k), is important for delivery of Cx43 to its respective membrane subdomain. This review covers recent advances in Cx43 trafficking and potential importance of alternatively translated Cx43 truncated isoforms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Wassim Basheer
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Robin Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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Kucera JP, Prudat Y, Marcu IC, Azzarito M, Ullrich ND. Slow conduction in mixed cultured strands of primary ventricular cells and stem cell-derived cardiomyocytes. Front Cell Dev Biol 2015; 3:58. [PMID: 26442264 PMCID: PMC4585316 DOI: 10.3389/fcell.2015.00058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/09/2015] [Indexed: 11/30/2022] Open
Abstract
Modern concepts for the treatment of myocardial diseases focus on novel cell therapeutic strategies involving stem cell-derived cardiomyocytes (SCMs). However, functional integration of SCMs requires similar electrophysiological properties as primary cardiomyocytes (PCMs) and the ability to establish intercellular connections with host myocytes in order to contribute to the electrical and mechanical activity of the heart. The aim of this project was to investigate the properties of cardiac conduction in a co-culture approach using SCMs and PCMs in cultured cell strands. Murine embryonic SCMs were pooled with fetal ventricular cells and seeded in predefined proportions on microelectrode arrays to form patterned strands of mixed cells. Conduction velocity (CV) was measured during steady state pacing. SCM excitability was estimated from action potentials measured in single cells using the patch clamp technique. Experiments were complemented with computer simulations of conduction using a detailed model of cellular architecture in mixed cell strands. CV was significantly lower in strands composed purely of SCMs (5.5 ± 1.5 cm/s, n = 11) as compared to PCMs (34.9 ± 2.9 cm/s, n = 21) at similar refractoriness (100% SCMs: 122 ± 25 ms, n = 9; 100% PCMs: 139 ± 67 ms, n = 14). In mixed strands combining both cell types, CV was higher than in pure SCMs strands, but always lower than in 100% PCM strands. Computer simulations demonstrated that both intercellular coupling and electrical excitability limit CV. These data provide evidence that in cultures of murine ventricular cardiomyocytes, SCMs cannot restore CV to control levels resulting in slow conduction, which may lead to reentry circuits and arrhythmias.
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Affiliation(s)
- Jan P Kucera
- Department of Physiology, University of Bern Bern, Switzerland
| | - Yann Prudat
- Department of Physiology, University of Bern Bern, Switzerland
| | - Irene C Marcu
- Department of Physiology, University of Bern Bern, Switzerland ; Department of Physiology and Pathophysiology, Heidelberg University Heidelberg, Germany
| | | | - Nina D Ullrich
- Department of Physiology and Pathophysiology, Heidelberg University Heidelberg, Germany
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Absence of connexin43 and connexin45 does not disturb pre- and peri-implantation development. ZYGOTE 2015; 24:457-64. [DOI: 10.1017/s0967199415000386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SummaryGap junctional intercellular communication is assumed to play an important role during pre- and peri-implantation development. In this study, we eliminated connexin43 (Cx43) and connexin45 (Cx45), major gap junctional proteins in the pre- and peri-implantation embryo. We generated Cx43−/−Cx45−/− embryos by Cx43+/−Cx45+/− intercrossing, because mice deficient in Cx43 (Cx43−/−) exhibit perinatal lethality and those deficient in Cx45 (Cx45−/−) exhibit early embryonic lethality. Wild-type, Cx43−/−, Cx45−/−, and Cx43−/−Cx45−/− blastocysts all showed similar outgrowths in in vitro culture. Moreover, Cx43−/−Cx45−/− embryos were obtained at the expected Mendelian ratio up to embryonic day 9.5, when the Cx45−/− mutation proved lethal. The Cx43−/−Cx45−/− embryos seemed to have no additional developmental abnormalities in comparison with the single knockout strains. Thus, pre- and peri-implantation development does not require Cx43 and Cx45. Other gap junctional proteins are expressed around these stages and these may compensate for the lack of Cx43 and Cx45.
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Benam KH, Dauth S, Hassell B, Herland A, Jain A, Jang KJ, Karalis K, Kim HJ, MacQueen L, Mahmoodian R, Musah S, Torisawa YS, van der Meer AD, Villenave R, Yadid M, Parker KK, Ingber DE. Engineered in vitro disease models. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2015; 10:195-262. [PMID: 25621660 DOI: 10.1146/annurev-pathol-012414-040418] [Citation(s) in RCA: 355] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ultimate goal of most biomedical research is to gain greater insight into mechanisms of human disease or to develop new and improved therapies or diagnostics. Although great advances have been made in terms of developing disease models in animals, such as transgenic mice, many of these models fail to faithfully recapitulate the human condition. In addition, it is difficult to identify critical cellular and molecular contributors to disease or to vary them independently in whole-animal models. This challenge has attracted the interest of engineers, who have begun to collaborate with biologists to leverage recent advances in tissue engineering and microfabrication to develop novel in vitro models of disease. As these models are synthetic systems, specific molecular factors and individual cell types, including parenchymal cells, vascular cells, and immune cells, can be varied independently while simultaneously measuring system-level responses in real time. In this article, we provide some examples of these efforts, including engineered models of diseases of the heart, lung, intestine, liver, kidney, cartilage, skin and vascular, endocrine, musculoskeletal, and nervous systems, as well as models of infectious diseases and cancer. We also describe how engineered in vitro models can be combined with human inducible pluripotent stem cells to enable new insights into a broad variety of disease mechanisms, as well as provide a test bed for screening new therapies.
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Affiliation(s)
- Kambez H Benam
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts 02115;
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Tanwar V, Bylund JB, Hu J, Yan J, Walthall JM, Mukherjee A, Heaton WH, Wang WD, Potet F, Rai M, Kupershmidt S, Knapik EW, Hatzopoulos AK. Gremlin 2 promotes differentiation of embryonic stem cells to atrial fate by activation of the JNK signaling pathway. Stem Cells 2015; 32:1774-88. [PMID: 24648383 DOI: 10.1002/stem.1703] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/17/2014] [Accepted: 02/23/2014] [Indexed: 01/23/2023]
Abstract
The bone morphogenetic protein antagonist Gremlin 2 (Grem2) is required for atrial differentiation and establishment of cardiac rhythm during embryonic development. A human Grem2 variant has been associated with familial atrial fibrillation, suggesting that abnormal Grem2 activity causes arrhythmias. However, it is not known how Grem2 integrates into signaling pathways to direct atrial cardiomyocyte differentiation. Here, we demonstrate that Grem2 expression is induced concurrently with the emergence of cardiovascular progenitor cells during differentiation of mouse embryonic stem cells (ESCs). Grem2 exposure enhances the cardiogenic potential of ESCs by 20-120-fold, preferentially inducing genes expressed in atrial myocytes such as Myl7, Nppa, and Sarcolipin. We show that Grem2 acts upstream to upregulate proatrial transcription factors CoupTFII and Hey1 and downregulate atrial fate repressors Irx4 and Hey2. The molecular phenotype of Grem2-induced atrial cardiomyocytes was further supported by induction of ion channels encoded by Kcnj3, Kcnj5, and Cacna1d genes and establishment of atrial-like action potentials shown by electrophysiological recordings. We show that promotion of atrial-like cardiomyocytes is specific to the Gremlin subfamily of BMP antagonists. Grem2 proatrial differentiation activity is conveyed by noncanonical BMP signaling through phosphorylation of JNK and can be reversed by specific JNK inhibitors, but not by dorsomorphin, an inhibitor of canonical BMP signaling. Taken together, our data provide novel mechanistic insights into atrial cardiomyocyte differentiation from pluripotent stem cells and will assist the development of future approaches to study and treat arrhythmias.
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Affiliation(s)
- Vineeta Tanwar
- Department of Medicine, Division of Cardiovascular Medicine, Nashville, Tennessee, USA
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40
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Bacharova L, Ugander M. Left ventricular hypertrophy: The relationship between the electrocardiogram and cardiovascular magnetic resonance imaging. Ann Noninvasive Electrocardiol 2014; 19:524-33. [PMID: 25367364 PMCID: PMC6932615 DOI: 10.1111/anec.12223] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Conventional assessment of left ventricular hypertrophy (LVH) using the electrocardiogram (ECG), for example, by the Sokolow-Lyon, Romhilt-Estes or Cornell criteria, have relied on assessing changes in the amplitude and/or duration of the QRS complex of the ECG to quantify LV mass. ECG measures of LV mass have typically been validated by imaging with echocardiography or cardiovascular magnetic resonance imaging (CMR). However, LVH can be the result of diverse etiologies, and LVH is also characterized by pathological changes in myocardial tissue characteristics on the genetic, molecular, cellular, and tissue level beyond a pure increase in the number of otherwise normal cardiomyocytes. For example, slowed conduction velocity through the myocardium, which can be due to diffuse myocardial fibrosis, has been shown to be an important determinant of conventional ECG LVH criteria regardless of LV mass. Myocardial tissue characterization by CMR has emerged to not only quantify LV mass, but also detect and quantify the extent and severity of focal or diffuse myocardial fibrosis, edema, inflammation, myocarditis, fatty replacement, myocardial disarray, and myocardial deposition of amyloid proteins (amyloidosis), glycolipids (Fabry disease), or iron (siderosis). This can be undertaken using CMR techniques including late gadolinium enhancement (LGE), T1 mapping, T2 mapping, T2* mapping, extracellular volume fraction (ECV) mapping, fat/water-weighted imaging, and diffusion tensor CMR. This review presents an overview of current and emerging concepts regarding the diagnostic possibilities of both ECG and CMR for LVH in an attempt to narrow gaps in our knowledge regarding the ECG diagnosis of LVH.
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Affiliation(s)
- Ljuba Bacharova
- International Laser CenterBratislavaSlovak Republic
- Institute of PathophysiologyMedical SchoolComenius UniversityBratislavaSlovak Republic
| | - Martin Ugander
- Department of Clinical PhysiologyKarolinska Institute and Karolinska University HospitalStockholmSweden
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Kirubakaran S, Chowdhury RA, Hall MCS, Patel PM, Garratt CJ, Peters NS. Fractionation of electrograms is caused by colocalized conduction block and connexin disorganization in the absence of fibrosis as AF becomes persistent in the goat model. Heart Rhythm 2014; 12:397-408. [PMID: 25444850 PMCID: PMC4315883 DOI: 10.1016/j.hrthm.2014.10.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Indexed: 01/25/2023]
Abstract
Background Electrogram fractionation and atrial fibrosis are both thought to be pathophysiological hallmarks of evolving persistence of atrial fibrillation (AF), but recent studies in humans have shown that they do not colocalize. The interrelationship and relative roles of fractionation and fibrotic change in AF persistence therefore remain unclear. Objective The aim of the study was to examine the hypothesis that electrogram fractionation with increasing persistence of AF results from localized conduction slowing or block due to changes in atrial connexin distribution in the absence of fibrotic change. Methods Of 12 goats, atrial burst pacemakers maintained AF in 9 goats for up to 3 consecutive 4-week periods. After each 4-week period, 3 goats underwent epicardial mapping studies of the right atrium and examination of the atrial myocardium for immunodetection of connexins 43 and 40 (Cx43 and Cx40) and quantification of connective tissue. Results Despite refractoriness returning to normal in between each 4-week period of AF, there was a cumulative increase in the prevalence of fractionated atrial electrograms during both atrial pacing (control and 1, 2, and 3 months period of AF 0.3%, 1.3% ± 1.5%, 10.6% ± 2%, and 17% ± 5%, respectively; analysis of variance, P < .05) and AF (0.3% ± 0.1%, 2.3% ± 1.2%, 14% ± 2%, and 23% ± 3%; P < .05) caused by colocalized areas of conduction block during both pacing (local conduction velocity <10 cm/s: 0.1% ± 0.1%, 0.3% ± 0.6%, 6.5% ± 3%, and 6.9% ± 4%; P < .05) and AF (1.5% ± 0.5%, 2.7% ± 1.1%, 10.1% ± 1.2%, and 13.6% ± 0.4%; P < .05), associated with an increase in the heterogeneity of Cx40 and lateralization of Cx43 (lateralization scores: 1.75 ± 0.89, 1.44 ± 0.31, 2.85 ± 0.96, and 2.94 ± 0.31; P < .02), but not associated with change in connective tissue content or net conduction velocity. Conclusion Electrogram fractionation with increasing persistence of AF results from slow localized conduction or block associated with changes in atrial connexin distribution in the absence of fibrotic change.
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Affiliation(s)
- Senthil Kirubakaran
- Manchester Heart Centre, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom.
| | | | - Mark C S Hall
- Manchester Heart Centre, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
| | | | - Clifford J Garratt
- Manchester Heart Centre, Manchester Royal Infirmary, Manchester, M13 9WL, United Kingdom
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42
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Kleber AG, Saffitz JE. Role of the intercalated disc in cardiac propagation and arrhythmogenesis. Front Physiol 2014; 5:404. [PMID: 25368581 PMCID: PMC4201087 DOI: 10.3389/fphys.2014.00404] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 09/30/2014] [Indexed: 01/28/2023] Open
Abstract
This review article discusses mechanisms underlying impulse propagation in cardiac muscle with specific emphasis on the role of the cardiac cell-to-cell junction, called the “intercalated disc.”The first part of this review deals with the role of gap junction channels, formed by connexin proteins, as a determinant of impulse propagation. It is shown that, depending on the underlying structure of the cellular network, decreasing the conductance of gap junction channels (so-called “electrical uncoupling”) may either only slow, or additionally stabilize propagation and reverse unidirectional propagation block to bidirectional propagation. This is because the safety factor for propagation increases with decreasing intercellular electrical conductance. The role of heterogeneous connexin expression, which may be present in disease states, is also discussed. The hypothesis that so-called ephaptic impulse transmission plays a role in heart and can substitute for electrical coupling has been revived recently. Whereas ephaptic transmission can be demonstrated in theoretical simulations, direct experimental evidence has not yet been presented. The second part of this review deals with the interaction of three protein complexes at the intercalated disc: (1) desmosomal and adherens junction proteins, (2) ion channel proteins, and (3) gap junction channels consisting of connexins. Recent work has revealed multiple interactions between these three protein complexes which occur, at least in part, at the level of protein trafficking. Such interactions are likely to play an important role in the pathogenesis of arrhythmogenic cardiomyopathy, and may reveal new therapeutic concepts and targets.
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Affiliation(s)
- Andre G Kleber
- Department of Pathology, Beth Israel Medical Center, Harvard Medical School Boston, MA, USA
| | - Jeffrey E Saffitz
- Department of Pathology, Beth Israel Medical Center, Harvard Medical School Boston, MA, USA
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43
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Prudat Y, Kucera JP. Nonlinear behaviour of conduction and block in cardiac tissue with heterogeneous expression of connexin 43. J Mol Cell Cardiol 2014; 76:46-54. [PMID: 25128085 DOI: 10.1016/j.yjmcc.2014.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/25/2014] [Accepted: 07/31/2014] [Indexed: 11/18/2022]
Abstract
Altered gap junctional coupling potentiates slow conduction and arrhythmias. To better understand how heterogeneous connexin expression affects conduction at the cellular scale, we investigated conduction in tissue consisting of two cardiomyocyte populations expressing different connexin levels. Conduction was mapped using microelectrode arrays in cultured strands of foetal murine ventricular myocytes with predefined contents of connexin 43 knockout (Cx43KO) cells. Corresponding computer simulations were run in randomly generated two-dimensional tissues mimicking the cellular architecture of the strands. In the cultures, the relationship between conduction velocity (CV) and Cx43KO cell content was nonlinear. CV first decreased significantly when Cx43KO content was increased from 0 to 50%. When the Cx43KO content was ≥60%, CV became comparable to that in 100% Cx43KO strands. Co-culturing Cx43KO and wild-type cells also resulted in significantly more heterogeneous conduction patterns and in frequent conduction blocks. The simulations replicated this behaviour of conduction. For Cx43KO contents of 10-50%, conduction was slowed due to wavefront meandering between Cx43KO cells. For Cx43KO contents ≥60%, clusters of remaining wild-type cells acted as electrical loads that impaired conduction. For Cx43KO contents of 40-60%, conduction exhibited fractal characteristics, was prone to block, and was more sensitive to changes in ion currents compared to homogeneous tissue. In conclusion, conduction velocity and stability behave in a nonlinear manner when cardiomyocytes expressing different connexin amounts are combined. This behaviour results from heterogeneous current-to-load relationships at the cellular level. Such behaviour is likely to be arrhythmogenic in various clinical contexts in which gap junctional coupling is heterogeneous.
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Affiliation(s)
- Yann Prudat
- Department of Physiology, University of Bern, Bühlplatz 5, CH-3012 Bern, Switzerland.
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bühlplatz 5, CH-3012 Bern, Switzerland.
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44
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Mezzano V, Pellman J, Sheikh F. Cell junctions in the specialized conduction system of the heart. ACTA ACUST UNITED AC 2014; 21:149-59. [PMID: 24738884 DOI: 10.3109/15419061.2014.905928] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Anchoring cell junctions are integral in maintaining electro-mechanical coupling of ventricular working cardiomyocytes; however, their role in cardiomyocytes of the cardiac conduction system (CCS) remains less clear. Recent studies in genetic mouse models and humans highlight the appearance of these cell junctions alongside gap junctions in the CCS and also show that defects in these structures and their components are associated with conduction impairments in the CCS. Here we outline current evidence supporting an integral relationship between anchoring and gap junctions in the CCS. Specifically we focus on (1) molecular and ultrastructural evidence for cell-cell junctions in specialized cardiomyocytes of the CCS, (2) genetic mouse models specifically targeting cell-cell junction components in the heart which exhibit CCS conduction defects and (3) human clinical studies from patients with cell-cell junction-based diseases that exhibit CCS electrophysiological defects.
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Affiliation(s)
- Valeria Mezzano
- Leon H. Charney Division of Cardiology, New York University School of Medicine , New York , New York
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45
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Hartman ME, Librande JR, Medvedev IO, Ahmad RN, Moussavi-Harami F, Gupta PP, Chien WM, Chin MT. An optimized and simplified system of mouse embryonic stem cell cardiac differentiation for the assessment of differentiation modifiers. PLoS One 2014; 9:e93033. [PMID: 24667642 PMCID: PMC3965510 DOI: 10.1371/journal.pone.0093033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/28/2014] [Indexed: 12/19/2022] Open
Abstract
Generating cardiomyocytes from embryonic stem cells is an important technique for understanding cardiovascular development, the origins of cardiovascular diseases and also for providing potential reagents for cardiac repair. Numerous methods have been published but often are technically challenging, complex, and are not easily adapted to assessment of specific gene contributions to cardiac myocyte differentiation. Here we report the development of an optimized protocol to induce the differentiation of mouse embryonic stem cells to cardiac myocytes that is simplified and easily adapted for genetic studies. Specifically, we made four critical findings that distinguish our protocol: 1) mouse embryonic stem cells cultured in media containing CHIR99021 and PD0325901 to maintain pluripotency will efficiently form embryoid bodies containing precardiac mesoderm when cultured in these factors at a reduced dosage, 2) low serum conditions promote cardiomyocyte differentiation and can be used in place of commercially prepared StemPro nutrient supplement, 3) the Wnt inhibitor Dkk-1 is dispensable for efficient cardiac differentiation and 4) tracking differentiation efficiency may be done with surface expression of PDGFRα alone. In addition, cardiac mesodermal precursors generated by this system can undergo lentiviral infection to manipulate the expression of specific target molecules to assess effects on cardiac myocyte differentiation and maturation. Using this approach, we assessed the effects of CHF1/Hey2 on cardiac myocyte differentiation, using both gain and loss of function. Overexpression of CHF1/Hey2 at the cardiac mesoderm stage had no apparent effect on cardiac differentiation, while knockdown of CHF1/Hey2 resulted in increased expression of atrial natriuretic factor and connexin 43, suggesting an alteration in the phenotype of the cardiomyocytes. In summary we have generated a detailed and simplified protocol for generating cardiomyocytes from mES cells that is optimized for investigating factors that affect cardiac differentiation.
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Affiliation(s)
- Matthew E. Hartman
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Jason R. Librande
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Ivan O. Medvedev
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Rabiah N. Ahmad
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Pritha P. Gupta
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Wei-Ming Chien
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michael T. Chin
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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46
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Lyon RC, Mezzano V, Wright AT, Pfeiffer E, Chuang J, Banares K, Castaneda A, Ouyang K, Cui L, Contu R, Gu Y, Evans SM, Omens JH, Peterson KL, McCulloch AD, Sheikh F. Connexin defects underlie arrhythmogenic right ventricular cardiomyopathy in a novel mouse model. Hum Mol Genet 2014; 23:1134-50. [PMID: 24108106 PMCID: PMC3919010 DOI: 10.1093/hmg/ddt508] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/06/2013] [Accepted: 10/04/2013] [Indexed: 12/27/2022] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) termed a 'disease of the desmosome' is an inherited cardiomyopathy that recently underwent reclassification owing to the identification of left-dominant and biventricular disease forms. Homozygous loss-of-function mutations in the desmosomal component, desmoplakin, are found in patients exhibiting a biventricular form of ARVC; however, no models recapitulate the postnatal hallmarks of the disease as seen in these patients. To gain insights into the homozygous loss-of-function effects of desmoplakin in the heart, we generated cardiomyocyte-specific desmoplakin-deficient mice (DSP-cKO) using ventricular myosin light chain-2-Cre mice. Homozygous DSP-cKO mice are viable but display early ultrastructural defects in desmosomal integrity leading to a cardiomyopathy reminiscent of a biventricular form of ARVC, which includes cell death and fibro-fatty replacement within the ventricle leading to biventricular dysfunction, failure and premature death. DSP-cKO mice also exhibited ventricular arrhythmias that are exacerbated with exercise and catecholamine stimulation. Furthermore, DSP-cKO hearts exhibited right ventricular conduction defects associated with loss of connexin 40 expression and electrical wavefront propagation defects associated with loss of connexin 43 expression. Dose-dependent assessment of the effects of loss of desmoplakin in neonatal ventricular cardiomyocytes revealed primary loss of connexin 43 levels, phosphorylation and function independent of the molecular dissociation of the mechanical junction complex and fibro-fatty manifestation associated with ARVC, suggesting a role for desmoplakin as a primary stabilizer of connexin integrity. In summary, we provide evidence for a novel mouse model, which is reminiscent of the postnatal onset of ARVC while highlighting mechanisms underlying a biventricular form of human ARVC.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Li Cui
- Department of Skaggs School of Pharmacy, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | | | | | - Sylvia M. Evans
- Department of Skaggs School of Pharmacy, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Boulaksil M, Winckels SK, Engelen MA, Stein M, van Veen TA, Jansen JA, Linnenbank AC, Bierhuizen MF, Groenewegen WA, van Oosterhout MF, Kirkels JH, de Jonge N, Varró A, Vos MA, de Bakker JM, van Rijen HV. Heterogeneous Connexin43 distribution in heart failure is associated with dispersed conduction and enhanced susceptibility to ventricular arrhythmias. Eur J Heart Fail 2014; 12:913-21. [DOI: 10.1093/eurjhf/hfq092] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Mohamed Boulaksil
- Interuniversity Cardiology Institute of The Netherlands; Utrecht The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | - Stephan K.G. Winckels
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
- Division Laboratory, Department of Pathology; University Medical Center Utrecht; Utrecht The Netherlands
| | - Markus A. Engelen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
- Department of Cardiology and Angiology; Hospital of the University of Muenster; Muenster Germany
| | - Mèra Stein
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
- Division of Heart and Lungs, Department of Cardiology; University Medical Center Utrecht; Utrecht The Netherlands
| | - Toon A.B. van Veen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | - John A. Jansen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | - André C. Linnenbank
- Interuniversity Cardiology Institute of The Netherlands; Utrecht The Netherlands
- Heart Failure Research Center; Academic Medical Center; Amsterdam The Netherlands
| | - Marti F.A. Bierhuizen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | - W. Antoinette Groenewegen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | | | - Johannes H. Kirkels
- Division of Heart and Lungs, Department of Cardiology; University Medical Center Utrecht; Utrecht The Netherlands
| | - Nicolaas de Jonge
- Division of Heart and Lungs, Department of Cardiology; University Medical Center Utrecht; Utrecht The Netherlands
| | - András Varró
- Department of Pharmacology and Pharmacotherapy; University of Szeged; Szeged Hungary
- Division for Cardiovascular Pharmacology; Hungarian Academy of Sciences; Szeged Hungary
| | - Marc A. Vos
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
| | - Jacques M.T. de Bakker
- Interuniversity Cardiology Institute of The Netherlands; Utrecht The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
- Heart Failure Research Center; Academic Medical Center; Amsterdam The Netherlands
| | - Harold V.M. van Rijen
- Division of Heart and Lungs, Department of Medical Physiology; University Medical Center Utrecht; Yalelaan 50 3584 CM Utrecht The Netherlands
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Heart-protective effect of n-3 PUFA demonstrated in a rat model of diabetic cardiomyopathy. Mol Cell Biochem 2013; 389:219-27. [PMID: 24378994 DOI: 10.1007/s11010-013-1943-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 12/18/2013] [Indexed: 12/16/2022]
Abstract
This study was designed to examine in vivo functional changes of the heart in the early stages of streptozotocin (STZ)-induced diabetic cardiomyopathy and to evaluate the effects of n-3 PUFA intake. Moreover, we investigated whether modulation of diabetes-related abnormalities of myocardial connexin-43 (Cx43), β-myosin heavy chain (β-MHC), and β1-adrenergic receptors (β1-AR) might be implicated in the cardioprotective mechanism of n-3 PUFA. Our results showed significantly reduced cardiac output and ejection fraction (using the microtip pressure-volume catheter technique) as well as stroke volume and stroke work, 4 weeks after STZ-induced diabetes, with improvement of these parameters due to n-3 PUFA consumption. Myocardial expression of Cx43 mRNA estimated by real-time polymerase chain reaction did not change in diabetic rats regardless of n-3 PUFA consumption (100 mg/100 g b.w./day). In contrast, the total and functional phosphorylated form of Cx43 protein increased significantly, and its cardiomyocyte-related distribution was disordered in the diabetic heart, but these changes normalized because of n-3 PUFA intake. Furthermore, acute diabetes was accompanied by decrease of myocardial β1-AR mRNA expression and mild yet nonsignificant increase of β-MHC mRNA. These alterations were not significantly affected by n-3 PUFA. In conclusion, the results point out that STZ-diabetic rats benefit from n-3 PUFA consumption particularly because of the attenuation of myocardial Cx43 abnormalities that most likely contributes to improvement of cardiac function.
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49
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Modelling the Effect of Gap Junctions on Tissue-Level Cardiac Electrophysiology. Bull Math Biol 2013; 76:431-54. [DOI: 10.1007/s11538-013-9927-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 12/02/2013] [Indexed: 01/25/2023]
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50
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Verheule S, Kaese S. Connexin diversity in the heart: insights from transgenic mouse models. Front Pharmacol 2013; 4:81. [PMID: 23818881 PMCID: PMC3694209 DOI: 10.3389/fphar.2013.00081] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/04/2013] [Indexed: 11/13/2022] Open
Abstract
Cardiac conduction is mediated by gap junction channels that are formed by connexin (Cx) protein subunits. The connexin family of proteins consists of more than 20 members varying in their biophysical properties and ability to combine with other connexins into heteromeric gap junction channels. The mammalian heart shows regional differences both in connexin expression profile and in degree of electrical coupling. The latter reflects functional requirements for conduction velocity which needs to be low in the sinoatrial and atrioventricular nodes and high in the ventricular conduction system. Over the past 20 years knowledge of the biology of gap junction channels and their role in the genesis of cardiac arrhythmias has increased enormously. This review focuses on the insights gained from transgenic mouse models. The mouse heart expresses Cx30, 30.2, 37, 40, 43, 45, and 46. For these connexins a variety of knock-outs, heart-specific knock-outs, conditional knock-outs, double knock-outs, knock-ins and overexpressors has been studied. We discuss the cardiac phenotype in these models and compare Cx expression between mice and men. Mouse models have enhanced our understanding of (patho)-physiological implications of Cx diversity in the heart. In principle connexin-specific modulation of electrical coupling in the heart represents an interesting treatment strategy for cardiac arrhythmias and conduction disorders.
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Affiliation(s)
- Sander Verheule
- Department of Physiology, Faculty of Medicine, Maastricht University Maastricht, Netherlands
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