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Farraha M, Rao R, Igoor S, Le TYL, Barry MA, Davey C, Kok C, Chong JJ, Kizana E. Recombinant Adeno-Associated Viral Vector-Mediated Gene Transfer of hTBX18 Generates Pacemaker Cells from Ventricular Cardiomyocytes. Int J Mol Sci 2022; 23:ijms23169230. [PMID: 36012498 PMCID: PMC9408910 DOI: 10.3390/ijms23169230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 12/03/2022] Open
Abstract
Sinoatrial node dysfunction can manifest as bradycardia, leading to symptoms of syncope and sudden cardiac death. Electronic pacemakers are the current standard of care but are limited due to a lack of biological chronotropic control, cost of revision surgeries, and risk of lead- and device-related complications. We therefore aimed to develop a biological alternative to electronic devices by using a clinically relevant gene therapy vector to demonstrate conversion of cardiomyocytes into sinoatrial node-like cells in an in vitro context. Neonatal rat ventricular myocytes were transduced with recombinant adeno-associated virus vector 6 encoding either hTBX18 or green fluorescent protein and maintained for 3 weeks. At the endpoint, qPCR, Western blot analysis and immunocytochemistry were used to assess for reprogramming into pacemaker cells. Cell morphology and Arclight action potentials were imaged via confocal microscopy. Compared to GFP, hTBX18-transduced cells showed that hTBX18, HCN4 and Cx45 were upregulated. Cx43 was significantly downregulated, while sarcomeric α-actinin remained unchanged. Cardiomyocytes transduced with hTBX18 acquired the tapering morphology of native pacemaker cells, as compared to the block-like, striated appearance of ventricular cardiomyocytes. Analysis of the action potentials showed phase 4 depolarization and a significant decrease in the APD50 of the hTBX18-transduced cells. We have demonstrated that rAAV-hTBX18 gene transfer to ventricular myocytes results in morphological, molecular, physiological, and functional changes, recapitulating the pacemaker phenotype in an in vitro setting. The generation of these induced pacemaker-like cells using a clinically relevant vector opens new prospects for biological pacemaker development.
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Affiliation(s)
- Melad Farraha
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Renuka Rao
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Sindhu Igoor
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Thi Y. L. Le
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Michael A. Barry
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
| | - Christopher Davey
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- School of Physics, the University of Sydney, Sydney 2006, Australia
| | - Cindy Kok
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - James J.H. Chong
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
| | - Eddy Kizana
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
- Correspondence:
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Saito Y, Nakamura K, Yoshida M, Sugiyama H, Akagi S, Miyoshi T, Morita H, Ito H. Enhancement of pacing function by HCN4 overexpression in human pluripotent stem cell-derived cardiomyocytes. Stem Cell Res Ther 2022; 13:141. [PMID: 35365232 PMCID: PMC8973792 DOI: 10.1186/s13287-022-02818-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background The number of patients with bradyarrhythmia and the number of patients with cardiac pacemakers are increasing with the aging population and the increase in the number of patients with heart diseases. Some patients in whom a cardiac pacemaker has been implanted experience problems such as pacemaker infection and inconvenience due to electromagnetic interference. We have reported that overexpression of HCN channels producing a pacemaker current in mouse embryonic stem cell-derived cardiomyocytes showed enhanced pacing function in vitro and in vivo. The aim of this study was to determine whether HCN4 overexpression in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) can strengthen the pacing function of the cells. Methods Human HCN4 was transduced in the AAVS1 locus of human induced pluripotent stem cells by nucleofection and HCN4-overexpressing iPSC-CMs were generated. Gene expression profiles, frequencies of spontaneous contraction and pacing abilities of HCN4-overexpressing and non-overexpressing iPSC-CMs in vitro were compared. Results HCN4-overexpressing iPSC-CMs showed higher spontaneous contraction rates than those of non-overexpressing iPSC-CMs. They responded to an HCN channel blocker and β adrenergic stimulation. The pacing rates against parent iPSC line-derived cardiomyocytes were also higher in HCN4-overexpressing iPSC-CMs than in non-overexpressing iPSC-CMs. Conclusions Overexpression of HCN4 showed enhancement of If current, spontaneous firing and pacing function in iPSC-CMs. These data suggest this transgenic cell line may be useful as a cardiac pacemaker. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-02818-y.
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Affiliation(s)
- Yukihiro Saito
- Department of Cardiovascular Medicine, Okayama University Hospital, Okayama, Japan.
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, 700-8558, Kita-ku, Okayama, Japan.
| | - Masashi Yoshida
- Department of Chronic Kidney Disease and Cardiovascular Disease, Dentistry, and Pharmaceutical Science, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Hiroki Sugiyama
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Satoshi Akagi
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, 700-8558, Kita-ku, Okayama, Japan
| | - Toru Miyoshi
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, 700-8558, Kita-ku, Okayama, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, 700-8558, Kita-ku, Okayama, Japan
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Effect of Shenfu Injection on Differentiation of Bone Marrow Mesenchymal Stem Cells into Pacemaker-Like Cells and Improvement of Pacing Function of Sinoatrial Node. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4299892. [PMID: 35186186 PMCID: PMC8853776 DOI: 10.1155/2022/4299892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/16/2022] [Accepted: 01/26/2022] [Indexed: 11/17/2022]
Abstract
Sick sinus syndrome (SSS), a complex type of cardiac arrhythmia, is a major health threat to humans. Shenfu injection (SFI), a formula of traditional Chinese medicine (TCM), is effective in improving bradyarrhythmia. However, the underlying mechanism of SFI’s therapeutic effect is subject to few systematic investigations. The purpose of the present research is to examine whether SFI can boost the differentiation effectiveness of bone marrow mesenchymal stem cells (BMSCs) into pacemaker-like cells and whether the transplantation of these cells can improve the pacing function of the sinoatrial node (SAN) in a rabbit model of SSS. BMSCs from New Zealand rabbits were extracted, followed by incubation in vitro. The flow cytometry was utilized to identify the expression of CD29, CD44, CD90, and CD105 surface markers. The isolated BMSCs were treated with SFI, and the whole-cell patch-clamp method was performed to detect hyperpolarization-the activated cyclic nucleotide-gated potassium channel 4 (HCN4) channel current activation curve. The SSS rabbit model was established using the formaldehyde wet dressing method, and BMSCs treated with SFI were transplanted into the SAN of the SSS rabbit model. We detected changes in the body-surface electrocardiogram and recorded dynamic heart rate measurements. Furthermore, transplanted SFI-treated BMSCs were subjected to HE staining, TUNEL staining, qPCR, western blotting, immunofluorescence, immunohistochemistry, and enzyme-linked immunosorbent assay to study their characteristics. Our results indicate that the transplantation of SFI-treated BMSCs into the SAN of SSS rabbits improved the pacing function of the SAN. In vitro data showed that SFI induced the proliferation of BMSCs, promoted their differentiation capacity into pacemaker-like cells, and increased the HCN4 expression in BMSCs. In vivo, the transplantation of SFI treated-BMSCs preserved the function of SAN in SSS rabbits, improved the expression of the HCN4 gene and gap junction proteins (Cx43 and Cx45), and significantly upregulated the expression of cAMP in the SAN, compared to the SSS model group. In summary, the present research demonstrated that SFI might enhance the differentiation capacity of BMSCs into pacemaker-like cells, hence offering a novel approach for the development of biological pacemakers. Additionally, we confirmed the effectiveness and safety of pacemaker-like cells differentiated from BMSCs in improving the pacing function of the SAN.
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Naumova N, Iop L. Bioengineering the Cardiac Conduction System: Advances in Cellular, Gene, and Tissue Engineering for Heart Rhythm Regeneration. Front Bioeng Biotechnol 2021; 9:673477. [PMID: 34409019 PMCID: PMC8365186 DOI: 10.3389/fbioe.2021.673477] [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: 02/27/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023] Open
Abstract
Heart rhythm disturbances caused by different etiologies may affect pediatric and adult patients with life-threatening consequences. When pharmacological therapy is ineffective in treating the disturbances, the implantation of electronic devices to control and/or restore normal heart pacing is a unique clinical management option. Although these artificial devices are life-saving, they display many limitations; not least, they do not have any capability to adapt to somatic growth or respond to neuroautonomic physiological changes. A biological pacemaker could offer a new clinical solution for restoring heart rhythms in the conditions of disorder in the cardiac conduction system. Several experimental approaches, such as cell-based, gene-based approaches, and the combination of both, for the generation of biological pacemakers are currently established and widely studied. Pacemaker bioengineering is also emerging as a technology to regenerate nodal tissues. This review analyzes and summarizes the strategies applied so far for the development of biological pacemakers, and discusses current translational challenges toward the first-in-human clinical application.
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Affiliation(s)
| | - Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Padua, Italy
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Darche FF, Rivinius R, Rahm AK, Köllensperger E, Leimer U, Germann G, Reiss M, Koenen M, Katus HA, Thomas D, Schweizer PA. In vivo cardiac pacemaker function of differentiated human mesenchymal stem cells from adipose tissue transplanted into porcine hearts. World J Stem Cells 2020; 12:1133-1151. [PMID: 33178397 PMCID: PMC7596441 DOI: 10.4252/wjsc.v12.i10.1133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/03/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mesenchymal stem cells (MSC) modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental animal models. Human MSC derived from adipose tissue (haMSC) differentiate into cells with pacemaker properties in vitro, but little is known about their behavior after intracardiac transplantation.
AIM To investigate whether haMSC elicit biological pacemaker function in vivo after transplantation into pig hearts.
METHODS haMSC under native conditions (nhaMSC) or after pre-conditioning by medium differentiation (dhaMSC) (n = 6 pigs each, 5 × 106 cells/animal) were injected into the porcine left ventricular free wall. Animals receiving PBS injection served as controls (n = 6). Four weeks later, total atrioventricular (AV)-block was induced by radiofrequency catheter ablation, and electronic pacemaker devices were implanted for backup stimulation and heart rate monitoring. Ventricular rate and rhythm of pigs were evaluated during a follow-up of 15 d post ablation by 12-lead-ECG with heart rate assessment, 24-h continuous rate monitoring recorded by electronic pacemaker, assessment of escape recovery time, and pharmacological challenge to address catecholaminergic rate response. Finally, hearts were analyzed by histological and immunohistochemical investigations.
RESULTS In vivo transplantation of dhaMSC into the left ventricular free wall of pigs elicited spontaneous and regular rhythms that were pace-mapped to ventricular injection sites (mean heart rate 72.2 ± 3.6 bpm; n = 6) after experimental total AV block. Ventricular rhythms were stably detected over a 15-d period and were sensitive to catecholaminergic stimulation (mean maximum heart rate 131.0 ± 6.2 bpm; n = 6; P < 0.001). Pigs, which received nhaMSC or PBS presented significantly lower ventricular rates (mean heart rates 47.2 ± 2.5 bpm and 37.4 ± 3.2 bpm, respectively; n = 6 each; P < 0.001) and exhibited little sensitivity towards catecholaminergic stimulation (mean maximum heart rates 76.4 ± 3.1 bpm and 60.5 ± 3.1 bpm, respectively; n = 6 each; P < 0.05). Histological and immunohistochemical evaluation of hearts treated with dhaMSC revealed local clusters of transplanted cells at the injection sites that lacked macrophage or lymphocyte infiltrations or tumor formation. Intense fluorescence signals at these sites indicated membrane expression of HCN4 and other pacemaker-specific proteins involved in cardiac automaticity and impulse propagation.
CONCLUSION dhaMSC transplanted into pig left ventricles sustainably induced rate-responsive ventricular pacemaker activity after in vivo engraftment for four weeks. The data suggest that pre-conditioned MSC may further differentiate along a pacemaker-related lineage after myocardial integration and may establish superior pacemaker properties in vivo.
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Affiliation(s)
- Fabrice F Darche
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
| | - Rasmus Rivinius
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
| | - Ann-Kathrin Rahm
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
| | - Eva Köllensperger
- Department of Plastic Surgery, ETHIANUM Klinik Heidelberg, Heidelberg D-69115, Germany
| | - Uwe Leimer
- Department of Plastic Surgery, ETHIANUM Klinik Heidelberg, Heidelberg D-69115, Germany
| | - Günter Germann
- Department of Plastic Surgery, ETHIANUM Klinik Heidelberg, Heidelberg D-69115, Germany
| | - Miriam Reiss
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
| | - Michael Koenen
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, Heidelberg D-69120, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
| | - Patrick A Schweizer
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg D-69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg D-69120, Germany
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Farraha M, Lu J, Trivic I, Barry MA, Chong J, Kumar S, Kizana E. Development of a sheep model of atrioventricular block for the application of novel therapies. PLoS One 2020; 15:e0229092. [PMID: 32040499 PMCID: PMC7010276 DOI: 10.1371/journal.pone.0229092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/29/2020] [Indexed: 11/30/2022] Open
Abstract
Introduction Sheep have been adopted as a pre-clinical large animal for scientific research as they are good models of cardiac anatomy and physiology, and allow for investigation of pathophysiological processes which occur in the large mammalian heart. There is, however, no defined model of atrioventricular block in sheep to allow for pre-clinical assessment of new cardiac treatment options. We therefore aimed to develop an adult sheep model of atrioventricular block with the focus on future novel applications. Methods and results We utilized six sheep to undergo two procedures each. The first procedure involved implantation of a single chamber pacemaker into the right ventricular apex, for baseline assessment over four weeks. The second procedure involved creating atrioventricular block by radiofrequency ablation of the His bundle, before holding for a further four weeks. Interrogation of pacemakers and electrocardiograms determined the persistence of atrioventricular block during the follow up period. Pacemakers were inserted, and atrioventricular block created in 6 animals using a conventional approach. One animal died following ablation of the His bundle, due to procedural complications. Four unablated sheep were assessed for baseline data over four weeks and showed 5.53 ± 1.28% pacing reliance. Five sheep were assessed over four weeks following His bundle ablation and showed continuous (98.89 ± 0.81%) ventricular pacing attributable to persistent atrioventricular block, with no major complications. Conclusion We have successfully developed, characterized and validated a large animal model of atrioventricular block that is stable and technically feasible in adult sheep. This model will allow for the advancement of novel therapies, including the development of cell and gene-based therapies.
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Affiliation(s)
- Melad Farraha
- Sydney Medical School, The University of Sydney, Australia
- Center for Heart Research, The Westmead Institute for Medical Research, Sydney, Australia
| | - Juntang Lu
- Department of Cardiology, Westmead Hospital, Sydney, Australia
| | - Ivana Trivic
- Department of Cardiology, Westmead Hospital, Sydney, Australia
| | | | - James Chong
- Sydney Medical School, The University of Sydney, Australia
- Center for Heart Research, The Westmead Institute for Medical Research, Sydney, Australia
- Department of Cardiology, Westmead Hospital, Sydney, Australia
| | - Saurabh Kumar
- Sydney Medical School, The University of Sydney, Australia
- Department of Cardiology, Westmead Hospital, Sydney, Australia
| | - Eddy Kizana
- Sydney Medical School, The University of Sydney, Australia
- Center for Heart Research, The Westmead Institute for Medical Research, Sydney, Australia
- Department of Cardiology, Westmead Hospital, Sydney, Australia
- * E-mail:
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Falconer D, Papageorgiou N, Androulakis E, Alfallouji Y, Lim WY, Providencia R, Tousoulis D. Biological therapies targeting arrhythmias: are cells and genes the answer? Expert Opin Biol Ther 2017; 18:237-249. [PMID: 29202595 DOI: 10.1080/14712598.2018.1410130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Arrhythmias can cause symptoms ranging from simple dizziness to life-threatening circulatory collapse. Current management includes medical therapy and procedures such as catheter ablation or device implantation. However, these strategies still pose a risk of serious side effects, and some patients remain symptomatic. Advancement in our understanding of how arrhythmias develop on the cellular level has made more targeted approaches possible. In addition, contemporary studies have found that several genes are involved in the pathogenesis of arrhythmias. AREAS COVERED In the present review, the authors explore the cellular and genetic mechanisms leading to arrhythmias as well as the progress that has been made in using both gene and cell therapy to treat tachy- and bradyarrhythmias. They also consider why gene and cell therapy has resulted into a few clinical trials with promising results, however still not applicable in routine clinical practice. EXPERT OPINION The question currently is whether such biological therapies could replace current established approaches. The contemporary evidence suggests that despite recent advances in this field, it will need more work in experimental models before this is applied into clinical practice. Gene and cell studies targeting conduction and repolarization are promising, but still not ready for use in the clinical setting.
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Affiliation(s)
| | | | | | | | - Wei Yao Lim
- b Barts Heart Centre, St Bartholomew's Hospital , London , UK
| | - Rui Providencia
- b Barts Heart Centre, St Bartholomew's Hospital , London , UK
| | - Dimitris Tousoulis
- d 1st Cardiology Department , Hippokration Hospital, Athens University Medical School , Athens , Greece
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Abstract
Cardiac arrhythmias are a leading cause of morbidity and mortality. Currently available therapeutic options lack sufficient efficacy and safety. Gene therapy has been proposed for treatment of cardiac arrhythmias. This review will discuss the current state of development for arrhythmia gene therapy. So far, all published studies are short-term, proof-of-concept animal studies. Potential replacement of cardiac pacemakers has been shown for combination gene therapy using the HCN2 gene and either the gene for adenylate cyclase, the skeletal muscle isoform of the sodium channel, or a dominant negative mutant of the potassium channel responsible for resting membrane potential. Atrial fibrillation has been prevented by gene transfer of either a dominant negative mutant of a repolarizing potassium channel, a gap junction, or an siRNA directed against caspase 3. Inherited arrhythmia syndromes have been corrected by replacement of the causative genes. Post-infarct ventricular tachycardia has been reduced by gene therapy with the skeletal muscle sodium channel and connexins and eliminated with the dominant negative mutant of the potassium channel responsible for resting membrane potential. These ideas show considerable promise. Long-term efficacy and safety studies are required to see if they can become viable therapies.
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Affiliation(s)
- J Kevin Donahue
- University of Massachusetts Medical School, Division of Cardiology, 55 Lake Ave. North, Worcester, MA 01655, United States.
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Lugenbiel P, Schweizer PA, Katus HA, Thomas D. Antiarrhythmic gene therapy - will biologics replace catheters, drugs and devices? Eur J Pharmacol 2016; 791:264-273. [PMID: 27593579 DOI: 10.1016/j.ejphar.2016.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/08/2016] [Accepted: 09/01/2016] [Indexed: 01/08/2023]
Abstract
The clinical management of heart rhythm disorders still constitutes a major challenge. The development of alternatives to current approaches is of significant interest in order to establish more effective therapies that increase quality of life and reduce symptoms and hospitalizations. Over the past two decades the mechanistic understanding of pathophysiological pathways underlying cardiac arrhythmias has advanced profoundly, opening up novel avenues for mechanism-based therapeutic approaches. In particular, gene therapy offers greater selectivity than small molecule-based or interventional treatment. The gene of interest is packaged into viral or non-viral carriers and delivered to the target area via direct injection or using catheter-based techniques, providing the advantage of site-restricted action in contrast to systemic application of drugs. This work summarizes the current knowledge on mechanistic background, application strategies, and preclinical outcome of antiarrhythmic gene therapy for atrial fibrillation, ventricular tachycardia, and modulation of sinus node function.
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Affiliation(s)
- Patrick Lugenbiel
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
| | - Patrick A Schweizer
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital, Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany.
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Feng Y, Yang P, Luo S, Zhang Z, Li H, Zhu P, Song Z. Shox2 influences mesenchymal stem cell fate in a co-culture model in vitro. Mol Med Rep 2016; 14:637-42. [PMID: 27222368 PMCID: PMC4918598 DOI: 10.3892/mmr.2016.5306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 02/24/2016] [Indexed: 01/26/2023] Open
Abstract
Sinoatrial node (SAN) dysfunction is a common cardiovascular problem, and the development of a cell sourced biological pacemaker has been the focus of cardiac electrophysiology research. The aim of biological pacemaker therapy is to produce SAN-like cells, which exhibit spontaneous activity characteristic of the SAN. Short stature homeobox 2 (Shox2) is an early cardiac transcription factor and is crucial in the formation and differentiation of the sinoatrial node (SAN). The present study aimed to improve pacemaker function by overexpression of Shox2 in canine mesenchymal stem cells (cMSCs) to induce a phenotype similar to native pacemaker cells. To achieve this objective, the cMSCs were transfected with lentiviral pLentis-mShox2-red fluorescent protein, and then co-cultured with rat neonatal cardiomyocytes (RNCMs) in vitro for 5–7 days. The feasibility of regulating the differentiation of cMSCs into pacemaker-like cells by Shox2 overexpression was investigated. Reverse transcription-quantitative polymerase chain reaction and western blotting showed that Shox2-transfected cMSCs expressed high levels of T box 3, hyperpolarization-activated cyclic nucleotide-gated cation channel and Connexin 45 genes, which participate in SAN development, and low levels of working myocardium genes, Nkx2.5 and Connexin 43. In addition, Shox2-transfected cMSCs were able to pace RNCMs with a rate faster than the control cells. In conclusion, these data indicate that overexpression of Shox2 in cMSCs can greatly enhance the pacemaker phenotype in a co-culture model in vitro.
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Affiliation(s)
- Yuanyuan Feng
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Pan Yang
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Shouming Luo
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Zhihui Zhang
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Huakang Li
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Ping Zhu
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Zhiyuan Song
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
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Saito Y, Nakamura K, Yoshida M, Sugiyama H, Ohe T, Kurokawa J, Furukawa T, Takano M, Nagase S, Morita H, Kusano KF, Ito H. Enhancement of Spontaneous Activity by HCN4 Overexpression in Mouse Embryonic Stem Cell-Derived Cardiomyocytes - A Possible Biological Pacemaker. PLoS One 2015; 10:e0138193. [PMID: 26384234 PMCID: PMC4575154 DOI: 10.1371/journal.pone.0138193] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/26/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Establishment of a biological pacemaker is expected to solve the persisting problems of a mechanical pacemaker including the problems of battery life and electromagnetic interference. Enhancement of the funny current (If) flowing through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and attenuation of the inward rectifier K+ current (IK1) flowing through inward rectifier potassium (Kir) channels are essential for generation of a biological pacemaker. Therefore, we generated HCN4-overexpressing mouse embryonic stem cells (mESCs) and induced cardiomyocytes that originally show poor IK1 currents, and we investigated whether the HCN4-overexpressing mESC-derived cardiomyocytes (mESC-CMs) function as a biological pacemaker in vitro. METHODS AND RESULTS The rabbit Hcn4 gene was transfected into mESCs, and stable clones were selected. mESC-CMs were generated via embryoid bodies and purified under serum/glucose-free and lactate-supplemented conditions. Approximately 90% of the purified cells were troponin I-positive by immunostaining. In mESC-CMs, expression level of the Kcnj2 gene encoding Kir2.1, which is essential for generation of IK1 currents that are responsible for stabilizing the resting membrane potential, was lower than that in an adult mouse ventricle. HCN4-overexpressing mESC-CMs expressed about a 3-times higher level of the Hcn4 gene than did non-overexpressing mESC-CMs. Expression of the Cacna1h gene, which encodes T-type calcium channel and generates diastolic depolarization in the sinoatrial node, was also confirmed. Additionally, genes required for impulse conduction including Connexin40, Connexin43, and Connexin45 genes, which encode connexins forming gap junctions, and the Scn5a gene, which encodes sodium channels, are expressed in the cells. HCN4-overexpressing mESC-CMs showed significantly larger If currents and more rapid spontaneous beating than did non-overexpressing mESC-CMs. The beating rate of HCN4-overexpressing mESC-CMs responded to ivabradine, an If inhibitor, and to isoproterenol, a beta-adrenergic receptor agonist. Co-culture of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with aggregates composed of mESC-CMs resulted in synchronized contraction of the cells. The beating rate of hiPSC-CMs co-cultured with aggregates of HCN4-overexpressing mESC-CMs was significantly higher than that of non-treated hiPSC-CMs and that of hiPSC-CMs co-cultured with aggregates of non-overexpressing mESC-CMs. CONCLUSIONS We generated HCN4-overexpresssing mESC-CMs expressing genes required for impulse conduction, showing rapid spontaneous beating, responding to an If inhibitor and beta-adrenergic receptor agonist, and having pacing ability in an in vitro co-culture system with other excitable cells. The results indicated that these cells could be applied to a biological pacemaker.
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Affiliation(s)
- Yukihiro Saito
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
- * E-mail:
| | - Masashi Yoshida
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Hiroki Sugiyama
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Tohru Ohe
- Sakakibara Heart Institute of Okayama, Okayama, Japan
| | - Junko Kurokawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsushi Furukawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, Kurume, Japan
| | - Satoshi Nagase
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Kengo F. Kusano
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
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12
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Li N, Csepe TA, Hansen BJ, Dobrzynski H, Higgins RSD, Kilic A, Mohler PJ, Janssen PML, Rosen MR, Biesiadecki BJ, Fedorov VV. Molecular Mapping of Sinoatrial Node HCN Channel Expression in the Human Heart. Circ Arrhythm Electrophysiol 2015; 8:1219-27. [PMID: 26304511 DOI: 10.1161/circep.115.003070] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/04/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND The hyperpolarization-activated current, If, plays an important role in sinoatrial node (SAN) pacemaking. Surprisingly, the distribution of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in human SAN has only been investigated at the mRNA level. Our aim was to define the expression pattern of HCN proteins in human SAN and different atrial regions. METHODS AND RESULTS Entire SAN complexes were isolated from failing (n=5) and nonfailing (n=9) human hearts cardioplegically arrested in the operating room. Three-dimensional intramural SAN structure was identified as the fibrotic compact region around the SAN artery with Connexin 43-negative pacemaker cardiomyocytes visualized in Masson's trichrome and immunostained cryosections. SAN protein was precisely isolated from the adjacent frozen SAN tissue blocks using a 16G biopsy needle. The purity of the SAN protein was confirmed by Connexin 43 immunoblot. All 3 HCN isoform proteins were detected in SAN. HCN1 was predominantly distributed in the human SAN with a 125.1±40.2 (n=12) expression ratio of SAN to right atrium. HCN2 and HCN4 expression levels were higher in SAN than in atria, with SAN to right atrium ratios of 6.1±0.9 and 4.6±0.6 (n=12), respectively. CONCLUSIONS This is the first study to conduct precise 3D molecular mapping of the human SAN by isolating pure pacemaker SAN tissue. All 3 cardiac HCN isoforms had higher expression in the SAN than in the atria. HCN1 was almost exclusively expressed in SAN, emphasizing its utility as a new specific molecular marker of the human SAN and as a potential target of specific treatments intended to modify sinus rhythm.
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Affiliation(s)
- Ning Li
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Thomas A Csepe
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Brian J Hansen
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Halina Dobrzynski
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Robert S D Higgins
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Ahmet Kilic
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Peter J Mohler
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Paul M L Janssen
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Michael R Rosen
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Brandon J Biesiadecki
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.)
| | - Vadim V Fedorov
- From the Department of Physiology & Cell Biology and Dorothy M. Davis Heart & Lung Research Institute (N.L., T.A.C., B.J.H., P.J.M., P.M.L.J., B.J.B., V.V.F.), Department of Surgery and Dorothy M. Davis Heart & Lung Research Institute (R.S.D.H., A.K.), The Ohio State University Wexner Medical Center, Columbus; Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom (H.D.); and Departments of Pharmacology and Pediatrics, Columbia University, New York, NY (M.R.R.).
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Abstract
Efforts to use gene therapy to create a biological pacemaker as an adjunct or replacement of electronic pacemakers have been ongoing for about 15 years. For the past decade, most of these efforts have focused on the hyperpolarization-activated cyclic nucleotide gated-(HCN) gene family of channels alone or in combination with other genes. The HCN gene family is the molecular correlate of the cardiac pacemaker current, If. It is a suitable basis for a biological pacemaker because it generates a depolarizing inward current primarily during diastole and is directly regulated by cyclic adenosine monophosphate (cAMP), thereby incorporating autonomic responsiveness. However, biological pacemakers based either on native HCN channels or on mutated HCN channels designed to optimize biophysical characteristics have failed to attain the desired basal and maximal physiological heart rates in large animals. More recent work has explored dual gene therapy approaches, combining an HCN variant with another gene to reduce outward current, increase an additional inward current, or enhance cAMP synthesis. Several of these dual gene therapy approaches have demonstrated appropriate basal and maximal heart rates with little or no reliance on a backup electronic pacemaker during the period of study. Future research, besides examining the efficacy of other gene combinations, will need to consider the additional issues of safety and persistence of the viral vectors often used to deliver these genes to a specific cardiac region.
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Affiliation(s)
- Gerard J. J. Boink
- Heart Center, Department of Clinical & Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Netherlands Heart Institute, ICIN, Utrecht, the Netherlands
| | - Richard B. Robinson
- Department of Pharmacology, Center for Molecular Therapeutics, Columbia University, New York, NY, USA
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14
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Lu W, Yaoming N, Boli R, Jun C, Changhai Z, Yang Z, Zhiyuan S. mHCN4 genetically modified canine mesenchymal stem cells provide biological pacemaking function in complete dogs with atrioventricular block. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 36:1138-49. [PMID: 23663261 DOI: 10.1111/pace.12154] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 03/01/2013] [Accepted: 03/06/2013] [Indexed: 01/13/2023]
Abstract
BACKGROUND The study was undertaken to assess the properties of mouse HCN4 (mHCN4)-modified canine mesenchymal stem cells (cMSCs) in dogs with experimentally induced complete atrioventricular (AV) block and electronic pacing. METHODS Complete AV block was induced in adult dogs who had undergone implantation of backup electronic pacemakers. cMSCs were transfected with mHCN4 genes. Evidence of successful IHCN4 expression was provided by patch-clamp detection. mHCN4-cMSCs or normal cMSCs were injected subepicardially into the left ventricular anterior wall of the dogs. Cardiac parameters were monitored for 6 weeks. Heart rate variability (HRV) was evaluated using quantitative Poincaré plots of R-RN against R-RN+1 intervals. cMSCs survival and expression of HCN4 in vivo were examined by histological studies and Western blot. RESULTS In 2 weeks, the maximum heart rate and the number of impulses generated from the injection sites were much higher in dogs injected with HCN4-modified MSCs than in control dogs. Basal heart rate increased in the HCN4 group and became fully stabilized by Week 4, evidenced by markedly reduced numbers of electronic pacemaker beats. At Week 2, HRV during exercise was significantly higher in HCN4 dogs than in controls as shown by descriptors of both instantaneous (SD1) and longer term (SD2) beat-to-beat deviations (P < 0.05). Hematoxylin-eosin staining and Western blot proved that cMSCs survive and express HCN4 protein in situ in heart of HCN4 dog. CONCLUSION Transplantation of mHCN4-modified cMSCs provided a stable biological pacemaking function that allowed an appropriate chronotropic response to physical exercise for up to 6 weeks.
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Affiliation(s)
- Wei Lu
- Department of Cardiology, Southwest Hospital, Third Military Medical University, Chongqing, China
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15
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Ishikawa K, Tilemann L, Ladage D, Aguero J, Leonardson L, Fish K, Kawase Y. Cardiac gene therapy in large animals: bridge from bench to bedside. Gene Ther 2012; 19:670-7. [PMID: 22301438 DOI: 10.1038/gt.2012.3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Several clinical trials are evaluating gene transfer as a therapeutic approach to treat cardiac diseases. Although it has just started on the path to clinical application, recent advances in gene delivery technologies with increasing knowledge of underlying mechanisms raise great expectations for the cardiac gene therapy. Although in vivo experiments using small animals provide the therapeutic potential of gene transfer, there exist many fundamental differences between the small animal and the human hearts. Before applying the therapy to clinical patients, large animal studies are a prerequisite to validate the efficacy in an animal model more relevant to the human heart. Several key factors including vector type, injected dose, delivery method and targeted cardiac disease are all important factors that determine the therapeutic efficacy. Selecting the most optimal combination of these factors is essential for successful gene therapy. In addition to the efficacy, safety profiles need to be addressed as well. In this regard, large animal studies are best suited for comprehensive evaluation at the preclinical stages of therapeutic development to ensure safe and effective gene transfer. As the cardiac gene therapy expands its potential, large animal studies will become more important to bridge the bench side knowledge to the clinical arena.
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Affiliation(s)
- K Ishikawa
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY 10029, USA.
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16
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Nof E, Antzelevitch C, Glikson M. The Contribution of HCN4 to normal sinus node function in humans and animal models. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2009; 33:100-6. [PMID: 19796353 DOI: 10.1111/j.1540-8159.2009.02563.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although sinus node bradycardia is a very common clinical condition, the cellular mechanisms contributing to abnormal sinus node function are not clearly delineated. In recent publications, mutations in the hyperpolarization-activated, cyclic nucleotide-gated (HCN) 4 channels have been associated with sinus bradycardia. These channels are thought to be crucial in generating the spontaneous sinus node action potential, in accelerating the heart rate during sympathetic drive, and decelerating heart rate during vagal stimulation. Humans carrying HCN4 mutations indeed display significant bradycardia. Recent studies generating HCN4 knock out mice suggested that although HCN4 is crucial in early development, other mechanisms may also play a role in the accelerated heat rate achieved during sympathetic drive. In this review, we focus on genotype-phenotype correlation of these mutations and discuss the relative contribution of various ion channels to sinus node function. We also discuss the importance of HCN in treating clinical conditions such as brady- and tachycardia.
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Affiliation(s)
- Eyal Nof
- Masonic Medical Research Laboratory, Utica New York, USA
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17
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Abstract
Several hundred thousand electronic pacemakers are implanted in the US each year to treat abnormally slow heart rates. Biological pacemaker research strives to replace this hardware, and the associated monitoring and maintenance, by using gene or cell therapy to create a permanent and autonomically responsive pacemaker. While there are numerous technological hurdles to overcome before this is a therapeutic reality, one critical issue is determining the optimal channel gene to employ in creating a biological pacemaker. This review discusses the pros and cons of various model systems for characterizing and evaluating the function of candidate channel genes. It is argued that a sequential approach that combines in silico, in vitro and in vivo models is required.
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18
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Baruscotti M, Barbuti A, Bucchi A. The cardiac pacemaker current. J Mol Cell Cardiol 2009; 48:55-64. [PMID: 19591835 DOI: 10.1016/j.yjmcc.2009.06.019] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/15/2009] [Accepted: 06/26/2009] [Indexed: 12/17/2022]
Abstract
In mammals cardiac rate is determined by the duration of the diastolic depolarization of sinoatrial node (SAN) cells which is mainly determined by the pacemaker I(f) current. f-channels are encoded by four members of the hyperpolarization-activated cyclic nucleotide-gated gene (HCN1-4) family. HCN4 is the most abundant isoform in the SAN, and its relevance to pacemaking has been further supported by the discovery of four loss-of-function mutations in patients with mild or severe forms of cardiac rate disturbances. Due to its selective contribution to pacemaking, the I(f) current is also the pharmacological target of a selective heart rate-reducing agent (ivabradine) currently used in the clinical practice. Albeit to a minor extent, the I(f) current is also present in other spontaneously active myocytes of the cardiac conduction system (atrioventricular node and Purkinje fibres). In working atrial and ventricular myocytes f-channels are expressed at a very low level and do not play any physiological role; however in certain pathological conditions over-expression of HCN proteins may represent an arrhythmogenic mechanism. In this review some of the most recent findings on f/HCN channels contribution to pacemaking are described.
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Affiliation(s)
- Mirko Baruscotti
- Department of Biomolecular Sciences and Biotechnology, Laboratory of Molecular Physiology and Neurobiology, Università degli Studi di Milano, Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata (CIMMBA), via Celoria 26, 20133 Milano, Italy.
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19
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Lakatta EG, DiFrancesco D. What keeps us ticking: a funny current, a calcium clock, or both? J Mol Cell Cardiol 2009; 47:157-70. [PMID: 19361514 DOI: 10.1016/j.yjmcc.2009.03.022] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 03/10/2009] [Accepted: 03/19/2009] [Indexed: 12/14/2022]
Affiliation(s)
- Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, Intramural Research Program, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825, USA.
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Barbuti A, Crespi A, Capilupo D, Mazzocchi N, Baruscotti M, DiFrancesco D. Molecular composition and functional properties of f-channels in murine embryonic stem cell-derived pacemaker cells. J Mol Cell Cardiol 2009; 46:343-51. [DOI: 10.1016/j.yjmcc.2008.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 11/14/2008] [Accepted: 12/03/2008] [Indexed: 10/21/2022]
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Chen YR, Yi FF, Li XY, Wang CY, Chen L, Yang XC, Su PX, Cai J. Resveratrol attenuates ventricular arrhythmias and improves the long-term survival in rats with myocardial infarction. Cardiovasc Drugs Ther 2008; 22:479-85. [PMID: 18853243 DOI: 10.1007/s10557-008-6141-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 09/18/2008] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The effects of resveratrol treatment on ventricular arrhythmia, survival, and late cardiac remodeling were evaluated in rats with myocardial infarction (MI). METHODS Three groups of rats (S: ham-operated, MI, and MI pre-treated with resveratrol) were treated in an in vivo MI model by ligation of left anterior descending coronary artery. The electrocardiogram signals were monitored and recorded for 24 h using an implanted telemetry transmitter. The incidence of ventricular arrhythmias during the first 24-h after MI was also evaluated. Meanwhile, invasive in vivo electrophysiology with pacing in the right ventricle was performed in each group to assess the inducibility of ventricular arrhythmias. RESULTS Administration of resveratrol significantly suppressed the MI-induced ventricular tachycardia and ventricular fibrillation (0.4 +/- 0.2 in Resv group vs. 7.1 +/- 2.2 in MI group episodes per hour per rat, P < 0.01). Data also showed that the incidence of inducible ventricular tachycardia was lower in the Resv group than the MI group (46% vs. 81%, P < 0.01). The infarct size and mortality in the Resv group at 14 weeks were reduced by 20% and 33%, respectively, compared with the MI groups. Results from patch clamp recording revealed that resveratrol inhibited L-type calcium current (I (Ca-L)), and selectively enhanced ATP-sensitive K(+) current (I (K,ATP)) in a concentration-dependent manner. CONCLUSION These results suggested that the emerging anti-arrhythmic character induced by resveratrol treatment in rat hearts could be mainly accounted for by inhibition of I (Ca-L) and enhancement of I (K,ATP). Administration of resveratrol also improved the long-term survival by suppressing left ventricular remodeling.
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Affiliation(s)
- You-Ren Chen
- Department of Cardiology, The Second Affiliated Hospital to Medical College, Shantou University, Shantou 515041, People's Republic of China
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22
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Blagbrough IS, Zara C. Animal models for target diseases in gene therapy--using DNA and siRNA delivery strategies. Pharm Res 2008; 26:1-18. [PMID: 18841450 PMCID: PMC7088656 DOI: 10.1007/s11095-008-9646-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 05/29/2008] [Indexed: 11/29/2022]
Abstract
Nanoparticles, including lipopolyamines leading to lipoplexes, liposomes, and polyplexes are targeted drug carrier systems in the current search for a successful delivery system for polynucleic acids. This review is focused on the impact of gene and siRNA delivery for studies of efficacy, pharmacodynamics, and pharmacokinetics within the setting of the wide variety of in vivo animal models now used. This critical appraisal of the recent literature sets out the different models that are currently being investigated to bridge from studies in cell lines through towards clinical reality. Whilst many scientists will be familiar with rodent (murine, fecine, cricetine, and musteline) models, few probably think of fish as a clinically relevant animal model, but zebrafish, madake, and rainbow trout are all being used. Larger animal models include rabbit, cat, dog, and cow. Pig is used both for the prevention of foot-and-mouth disease and human diseases, sheep is a model for corneal transplantation, and the horse naturally develops arthritis. Non-human primate models (macaque, common marmoset, owl monkey) are used for preclinical gene vector safety and efficacy trials to bridge the gap prior to clinical studies. We aim for the safe development of clinically effective delivery systems for DNA and RNAi technologies.
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Affiliation(s)
- Ian S Blagbrough
- Department of Pharmacy and Pharmacology, University of Bath, Bath, BA2 7AY, UK.
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Boink GJJ, Verkerk AO, van Amersfoorth SCM, Tasseron SJ, van der Rijt R, Bakker D, Linnenbank AC, van der Meulen J, de Bakker JMT, Seppen J, Tan HL. Engineering physiologically controlled pacemaker cells with lentiviral HCN4 gene transfer. J Gene Med 2008; 10:487-97. [PMID: 18383475 DOI: 10.1002/jgm.1172] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Research on biological pacemakers for the heart has so far mainly focused on short-term gene and cell therapies. To develop a clinically relevant biological pacemaker, long-term function and incorporation of autonomic modulation are crucial. Lentiviral vectors can mediate long-term gene expression, while isoform 4 of the Hyperpolarization-activated Cyclic Nucleotide-gated channel (encoded by HCN4) contributes to pacemaker function and responds maximally to cAMP, the second messenger in autonomic modulation. MATERIAL AND METHODS Action potential (AP) properties and pacemaker current (I(f)) were studied in single neonatal rat ventricular myocytes that overexpressed HCN4 after lentiviral gene transduction. Autonomic responsiveness and cycle length stability were studied using extracellular electrograms of confluent cultured monolayers. RESULTS Perforated patch-clamp experiments demonstrated that HCN4-transduced single cardiac myocytes exhibited a 10-fold higher I(f) than non-transduced single myocytes, along with slow diastolic depolarization, comparable to pacemaker cells of the sinoatrial node, the dominant native pacemaker. HCN4-transduced monolayers exhibited a 47% increase in beating rate, compared to controls. Upon addition of DBcAMP, HCN4-transduced monolayers had beating rates which were 54% faster than baseline and significantly more regular than controls. CONCLUSIONS Lentiviral vectors efficiently transduce cardiac myocytes and mediate functional gene expression. Because HCN4-transduced myocytes demonstrate an increase in spontaneous beating rate and responsiveness to autonomic modulation, this approach may be useful to create a biological pacemaker.
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Affiliation(s)
- Gerard J J Boink
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Abstract
The heart automaticity is a fundamental physiological function in higher organisms. The spontaneous activity is initiated by specialized populations of cardiac cells generating periodical electrical oscillations. The exact cascade of steps initiating the pacemaker cycle in automatic cells has not yet been entirely elucidated. Nevertheless, ion channels and intracellular Ca(2+) signaling are necessary for the proper setting of the pacemaker mechanism. Here, we review the current knowledge on the cellular mechanisms underlying the generation and regulation of cardiac automaticity. We discuss evidence on the functional role of different families of ion channels in cardiac pacemaking and review recent results obtained on genetically engineered mouse strains displaying dysfunction in heart automaticity. Beside ion channels, intracellular Ca(2+) release has been indicated as an important mechanism for promoting automaticity at rest as well as for acceleration of the heart rate under sympathetic nerve input. The potential links between the activity of ion channels and Ca(2+) release will be discussed with the aim to propose an integrated framework of the mechanism of automaticity.
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Affiliation(s)
- Matteo E Mangoni
- Institute of Functional Genomics, Department of Physiology, Centre National de la Recherche Scientifique UMR5203, INSERM U661, University of Montpellier I and II, Montpellier, France.
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25
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Barbuti A, DiFrancesco D. Control of cardiac rate by "funny" channels in health and disease. Ann N Y Acad Sci 2008; 1123:213-23. [PMID: 18375593 DOI: 10.1196/annals.1420.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Activation of the "funny" (pacemaker, I f) current during the diastolic depolarization phase of an action potential is the main mechanism underlying spontaneous, rhythmic activity of cardiac pacemaker cells. In the past three decades, a wealth of evidence elucidating the function of the funny current in the generation and modulation of cardiac pacemaker activity has been gathered. The slope of early diastolic depolarization, and thus the heart rate, is controlled precisely by the degree of I f activation during diastole. I f is also accurately and rapidly modulated by changes of the cytosolic concentration of the second messenger cAMP, operated by the autonomous nervous system through beta-adrenergic, mainly beta2, and in the opposite way by muscarinic receptor, stimulation. Recently, novel in vivo data, both in animal models and humans, have been collected that confirm the key role of I f in pacemaking. In particular, an inheritable point mutation in the cyclic nucleotide-binding domain of human HCN4, the main hyperpolarization-activated cyclic nucleotide (HCN) isoform contributing to native funny channels of the sinoatrial node, was shown to be associated with sinus bradycardia in a large family. Because of their properties, funny channels have long been a major target of classical pharmacological research and are now target of innovative gene/cell-based therapeutic approaches aimed to exploit their function in cardiac rate control.
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Affiliation(s)
- Andrea Barbuti
- Department of Biomolecular Sciences and Biotechnology, The PaceLab, University of Milan, Milan, Italy
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Tong S, Yao Q, Wan Y, Zhou J, Shu M, Zhong L, Li Y, Zhang Q, Yindai J, Song Z. Development of functional I f channels in mMSCs after transfection with mHCN4: effects on cell morphology and mechanical activity in vitro. Cardiology 2008; 112:114-21. [PMID: 18594141 DOI: 10.1159/000141919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Accepted: 03/06/2008] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To study the functional properties of I(f) channels and the changes in mechanical activity of mouse mesenchymal stem cells (mMSCs) transfected with mHCN4. METHODS mMSCs were purified by using CD11b-immunomagnetic microbeads and transfected with pMSCV-mHCN4-EGFP or pMSCV-EGFP. We examined the kinetic characteristics of the mHCN4 channel. The morphological changes of positively transfected mMSCs were investigated at the same time. RESULTS The I(f) current recorded from the experimental group was sensitive to extracellular Cs(+) (-44.5 +/- 4.2 vs. -5.5 +/- 1.0 pA/pF, p < 0.001). The half-maximal activation was -99.0 +/- 5.8 mV. The time constant of activation was 451 +/- 61 ms under -140 mV. The control cells did not show the current under the same conditions. The absolute values of half-maximal activation decreased in the presence of cAMP or cGMP in the experimental group (-78.6 +/- 10.4 and -85.7 +/- 8.6 vs. -99.0 +/- 5.8 mV, respectively, p < 0.05). mMSCs transfected with pMSCV-mHCN4-EGFP could form spontaneous beating cells. Extracellular Cs(+) decreased the beating rate significantly (196 +/- 50 vs. 66 +/- 23 bmp, p < 0.01). CONCLUSIONS Functional I(f) channels can be reconstructed in mMSCs infected with mHCN4. mMSCs modified by successful transfection with mHCN4 can differentiate so as to develop spontaneous mechanical activity.
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Affiliation(s)
- Shifei Tong
- Department of Cardiology, Southwest Hospital, Third Military Medical Academy, Chongqing, China
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Maue RA. Understanding ion channel biology using epitope tags: progress, pitfalls, and promise. J Cell Physiol 2007; 213:618-25. [PMID: 17849449 DOI: 10.1002/jcp.21259] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Epitope tags have been increasingly used to understand ion channel subunit assembly and interaction, trafficking, subcellular localization, and function in living cells. In particular, epitope tags have proven extremely useful for analyses of closely related, highly homologous channel subunits in endogenous cell contexts in vitro and in vivo, where multiple channel isoforms may be expressed. However, as the variety of epitope tags that have been used has expanded, and the use of tagged channel subunits has become increasingly sophisticated and widespread, there has also been an increase in the number of examples highlighting the potential problems associated with the use of epitope tags for ion channel studies. Described here are some of the epitope tags that have been used to study ion channel subunits, including the HA, FLAG, myc, His6, and green fluorescent protein (GFP) epitopes, as well as some of the applications and avenues of research in which they have proven advantageous. Potential pitfalls and caveats associated with the use of these epitope tags are also discussed, with an emphasis on the need to include careful characterization of epitope-tagged channel subunits as part of their construction. Finally, potential avenues for future investigation and the development of this approach are considered.
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Affiliation(s)
- Robert A Maue
- Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
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