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Richardson SJ, Thekkedam CG, Casarotto MG, Beard NA, Dulhunty AF. FKBP12 binds to the cardiac ryanodine receptor with negative cooperativity: implications for heart muscle physiology in health and disease. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220169. [PMID: 37122219 PMCID: PMC10150220 DOI: 10.1098/rstb.2022.0169] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Cardiac ryanodine receptors (RyR2) release the Ca2+ from intracellular stores that is essential for cardiac myocyte contraction. The ion channel opening is tightly regulated by intracellular factors, including the FK506 binding proteins, FKBP12 and FKBP12.6. The impact of these proteins on RyR2 activity and cardiac contraction is debated, with often apparently contradictory experimental results, particularly for FKBP12. The isoform that regulates RyR2 has generally been considered to be FKBP12.6, despite the fact that FKBP12 is the major isoform associated with RyR2 in some species and is bound in similar proportions to FKBP12.6 in others, including sheep and humans. Here, we show time- and concentration-dependent effects of adding FKBP12 to RyR2 channels that were partly depleted of FKBP12/12.6 during isolation. The added FKBP12 displaced most remaining endogenous FKBP12/12.6. The results suggest that FKBP12 activates RyR2 with high affinity and inhibits RyR2 with lower affinity, consistent with a model of negative cooperativity in FKBP12 binding to each of the four subunits in the RyR tetramer. The easy dissociation of some FKBP12/12.6 could dynamically alter RyR2 activity in response to changes in in vivo regulatory factors, indicating a significant role for FKBP12/12.6 in Ca2+ signalling and cardiac function in healthy and diseased hearts. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- S J Richardson
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - C G Thekkedam
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - M G Casarotto
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - N A Beard
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - A F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
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2
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Abstract
This Review provides an update on ryanodine receptors (RyRs) and their role in human diseases of heart, muscle, and brain. Calcium (Ca2+) is a requisite second messenger in all living organisms. From C. elegans to mammals, Ca2+ is necessary for locomotion, bodily functions, and neural activity. However, too much of a good thing can be bad. Intracellular Ca2+ overload can result in loss of function and death. Intracellular Ca2+ release channels evolved to safely provide large, rapid Ca2+ signals without exposure to toxic extracellular Ca2+. RyRs are intracellular Ca2+ release channels present throughout the zoosphere. Over the past 35 years, our knowledge of RyRs has advanced to the level of atomic-resolution structures revealing their role in the mechanisms underlying the pathogenesis of human disorders of heart, muscle, and brain. Stress-induced RyR-mediated intracellular Ca2+ leak in the heart can promote heart failure and cardiac arrhythmias. In skeletal muscle, RyR1 leak contributes to muscle weakness in inherited myopathies, to age-related loss of muscle function and cancer-associated muscle weakness, and to impaired muscle function in muscular dystrophies, including Duchenne. In the brain, leaky RyR channels contribute to cognitive dysfunction in Alzheimer's disease, posttraumatic stress disorder, and Huntington's disease. Novel therapeutics targeting dysfunctional RyRs are showing promise.
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Dridi H, Forrester F, Umanskaya A, Xie W, Reiken S, Lacampagne A, Marks A. Role of oxidation of excitation-contraction coupling machinery in age-dependent loss of muscle function in C. elegans. eLife 2022; 11:75529. [PMID: 35506650 PMCID: PMC9113742 DOI: 10.7554/elife.75529] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 04/27/2022] [Indexed: 11/13/2022] Open
Abstract
Age-dependent loss of body wall muscle function and impaired locomotion occur within 2 weeks in C. elegans; however, the underlying mechanism has not been fully elucidated. In humans, age-dependent loss of muscle function occurs at about 80 years of age and has been linked to dysfunction of ryanodine receptor (RyR)/intracellular calcium (Ca2+) release channels on the sarcoplasmic reticulum (SR). Mammalian skeletal muscle RyR1 channels undergo age-related remodeling due to oxidative overload, leading to loss of the stabilizing subunit calstabin1 (FKBP12) from the channel macromolecular complex. This destabilizes the closed state of the channel resulting in intracellular Ca2+ leak, reduced muscle function, and impaired exercise capacity. We now show that the C. elegans RyR homolog, UNC-68, exhibits a remarkable degree of evolutionary conservation with mammalian RyR channels and similar age-dependent dysfunction. Like RyR1 in mammals UNC-68 encodes a protein that comprises a macromolecular complex which includes the calstabin1 homolog FKB-2 and is immunoreactive with antibodies raised against the RyR1 complex. Further, as in aged mammals, UNC-68 is oxidized and depleted of FKB-2 in an age-dependent manner, resulting in 'leaky' channels, depleted SR Ca2+ stores, reduced body wall muscle Ca2+ transients, and age-dependent muscle weakness. FKB-2 (ok3007)-deficient worms exhibit reduced exercise capacity. Pharmacologically induced oxidization of UNC-68 and depletion of FKB-2 from the channel independently caused reduced body wall muscle Ca2+ transients. Preventing FKB-2 depletion from the UNC-68 macromolecular complex using the Rycal drug S107 improved muscle Ca2+ transients and function. Taken together, these data suggest that UNC-68 oxidation plays a role in age-dependent loss of muscle function. Remarkably, this age-dependent loss of muscle function induced by oxidative overload, which takes ~2 years in mice and ~80 years in humans, occurs in less than 2-3 weeks in C. elegans, suggesting that reduced antioxidant capacity may contribute to the differences in life span amongst species.
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Affiliation(s)
- Haikel Dridi
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
| | - Frances Forrester
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
| | - Alisa Umanskaya
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
| | - Wenjun Xie
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
| | - Alain Lacampagne
- U1046, Montpellier University, INSERM, CNRS, Montpellier, France
| | - Andrew Marks
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States
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Yang S, Li R, Chen J, Li Z, Huang Z, Xie W. Calcium Spark Detection and Event-Based Classification of Single Cardiomyocyte Using Deep Learning. Front Physiol 2021; 12:770051. [PMID: 34819876 PMCID: PMC8607692 DOI: 10.3389/fphys.2021.770051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Ca2+ sparks are the elementary Ca2+ release events in cardiomyocytes, altered properties of which lead to impaired Ca2+ handling and finally contribute to cardiac pathology under various diseases. Despite increasing use of machine-learning algorithms in deciphering the content of biological and medical data, Ca2+ spark images and data are yet to be deeply learnt and analyzed. In the present study, we developed a deep residual convolutional neural network method to detect Ca2+ sparks. Compared to traditional detection methods with arbitrarily defined thresholds to distinguish signals from noises, our new method detected more Ca2+ sparks with lower amplitudes but similar spatiotemporal distributions, thereby indicating that our new algorithm detected many very weak events that are usually omitted when using traditional detection methods. Furthermore, we proposed an event-based logistic regression and binary classification model to classify single cardiomyocytes using Ca2+ spark characteristics, which to date have generally been used only for simple statistical analyses and comparison between normal and diseased groups. Using this new detection algorithm and classification model, we succeeded in distinguishing wild type (WT) vs RyR2-R2474S± cardiomyocytes with 100% accuracy, and vehicle vs isoprenaline-insulted WT cardiomyocytes with 95.6% accuracy. The model can be extended to judge whether a small number of cardiomyocytes (and so the whole heart) are under a specific cardiac disease. Thus, this study provides a novel and powerful approach for the research and application of calcium signaling in cardiac diseases.
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Affiliation(s)
- Shengqi Yang
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Ran Li
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Jiliang Chen
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Zhen Li
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Zhangqin Huang
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Wenjun Xie
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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Borile G, Zaglia T, E. Lehnart S, Mongillo M. Multiphoton Imaging of Ca 2+ Instability in Acute Myocardial Slices from a RyR2R2474S Murine Model of Catecholaminergic Polymorphic Ventricular Tachycardia. J Clin Med 2021; 10:jcm10132821. [PMID: 34206855 PMCID: PMC8269190 DOI: 10.3390/jcm10132821] [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: 05/17/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/27/2022] Open
Abstract
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a familial stress-induced arrhythmia syndrome, mostly caused by mutations in Ryanodine receptor 2 (RyR2), the sarcoplasmic reticulum (SR) Ca2+ release channel in cardiomyocytes. Pathogenetic mutations lead to gain of function in the channel, causing arrhythmias by promoting diastolic spontaneous Ca2+ release (SCR) from the SR and delayed afterdepolarizations. While the study of Ca2+ dynamics in single cells from murine CPVT models has increased our understanding of the disease pathogenesis, questions remain on the mechanisms triggering the lethal arrhythmias at tissue level. Here, we combined subcellular analysis of Ca2+ signals in isolated cardiomyocytes and in acute thick ventricular slices of RyR2R2474S knock-in mice, electrically paced at different rates (1–5 Hz), to identify arrhythmogenic Ca2+ dynamics, from the sub- to the multicellular perspective. In both models, RyR2R2474S cardiomyocytes had increased propensity to develop SCR upon adrenergic stimulation, which manifested, in the slices, with Ca2+ alternans and synchronous Ca2+ release events in neighboring cardiomyocytes. Analysis of Ca2+ dynamics in multiple cells in the tissue suggests that SCRs beget SCRs in contiguous cells, overcoming the protective electrotonic myocardial coupling, and potentially generating arrhythmia triggering foci. We suggest that intercellular interactions may underscore arrhythmic propensity in CPVT hearts with ‘leaky’ RyR2.
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Affiliation(s)
- Giulia Borile
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (G.B.); (T.Z.)
- Veneto Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (G.B.); (T.Z.)
- Veneto Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy
| | - Stephan E. Lehnart
- Heart Research Heart Research Center Göttingen, Cellular Biophysics and Translational Cardi-Ology Section, Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37073 Göttingen, Germany;
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, 37073 Göttingen, Germany
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy; (G.B.); (T.Z.)
- Veneto Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy
- Correspondence: ; Tel.: +39-049-7923229; Fax: +39-049-7923250
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Fang J, Wei X, Li H, Hu N, Liu X, Xu D, Zhang T, Wan H, Wang P, Xie X. Cardiomyocyte electrical-mechanical synchronized model for high-content, dose-quantitative and time-dependent drug assessment. MICROSYSTEMS & NANOENGINEERING 2021; 7:26. [PMID: 34567740 PMCID: PMC8433219 DOI: 10.1038/s41378-021-00247-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 01/13/2021] [Accepted: 01/31/2021] [Indexed: 05/16/2023]
Abstract
Cardiovascular diseases have emerged as a significant threat to human health. However, drug development is a time-consuming and costly process, and few drugs pass the preclinical assessment of safety and efficacy. The existing patch-clamp, Ca2+ imaging, and microelectrode array technologies in cardiomyocyte models for drug preclinical screening have suffered from issues of low throughput, limited long-term assessment, or inability to synchronously and correlatively analyze electrical and mechanical signals. Here, we develop a high-content, dose-quantitative and time-dependent drug assessment platform based on an electrical-mechanical synchronized (EMS) biosensing system. This microfabricated EMS can record both firing potential (FP) and mechanical beating (MB) signals from cardiomyocytes and extract a variety of characteristic parameters from these two signals (FP-MB) for further analysis. This system was applied to test typical ion channel drugs (lidocaine and isradipine), and the dynamic responses of cardiomyocytes to the tested drugs were recorded and analyzed. The high-throughput characteristics of the system can facilitate simultaneous experiments on a large number of samples. Furthermore, a database of various cardiac drugs can be established by heat map analysis for rapid and effective screening of drugs. The EMS biosensing system is highly promising as a powerful tool for the preclinical development of new medicines.
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Affiliation(s)
- Jiaru Fang
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
| | - Xinwei Wei
- Biosensor National Special Laboratory, Key Laboratory of Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Hongbo Li
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
| | - Ning Hu
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050 China
| | - Xingxing Liu
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
| | - Dongxin Xu
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
| | - Tao Zhang
- School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 510006 China
| | - Hao Wan
- Biosensor National Special Laboratory, Key Laboratory of Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027 China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050 China
| | - Ping Wang
- Biosensor National Special Laboratory, Key Laboratory of Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027 China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050 China
| | - Xi Xie
- The First Affiliated Hospital of Sun Yat-Sen University; School of Electronics and Information Technology, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou, 510006 China
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7
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Wei J, Yao J, Belke D, Guo W, Zhong X, Sun B, Wang R, Paul Estillore J, Vallmitjana A, Benitez R, Hove-Madsen L, Alvarez-Lacalle E, Echebarria B, Chen SRW. Ca 2+-CaM Dependent Inactivation of RyR2 Underlies Ca 2+ Alternans in Intact Heart. Circ Res 2020; 128:e63-e83. [PMID: 33375811 DOI: 10.1161/circresaha.120.318429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
RATIONALE Ca2+ alternans plays an essential role in cardiac alternans that can lead to ventricular fibrillation, but the mechanism underlying Ca2+ alternans remains undefined. Increasing evidence suggests that Ca2+ alternans results from alternations in the inactivation of cardiac RyR2 (ryanodine receptor 2). However, what inactivates RyR2 and how RyR2 inactivation leads to Ca2+ alternans are unknown. OBJECTIVE To determine the role of CaM (calmodulin) on Ca2+ alternans in intact working mouse hearts. METHODS AND RESULTS We used an in vivo local gene delivery approach to alter CaM function by directly injecting adenoviruses expressing CaM-wild type, a loss-of-function CaM mutation, CaM (1-4), and a gain-of-function mutation, CaM-M37Q, into the anterior wall of the left ventricle of RyR2 wild type or mutant mouse hearts. We monitored Ca2+ transients in ventricular myocytes near the adenovirus-injection sites in Langendorff-perfused intact working hearts using confocal Ca2+ imaging. We found that CaM-wild type and CaM-M37Q promoted Ca2+ alternans and prolonged Ca2+ transient recovery in intact RyR2 wild type and mutant hearts, whereas CaM (1-4) exerted opposite effects. Altered CaM function also affected the recovery from inactivation of the L-type Ca2+ current but had no significant impact on sarcoplasmic reticulum Ca2+ content. Furthermore, we developed a novel numerical myocyte model of Ca2+ alternans that incorporates Ca2+-CaM-dependent regulation of RyR2 and the L-type Ca2+ channel. Remarkably, the new model recapitulates the impact on Ca2+ alternans of altered CaM and RyR2 functions under 9 different experimental conditions. Our simulations reveal that diastolic cytosolic Ca2+ elevation as a result of rapid pacing triggers Ca2+-CaM dependent inactivation of RyR2. The resultant RyR2 inactivation diminishes sarcoplasmic reticulum Ca2+ release, which, in turn, reduces diastolic cytosolic Ca2+, leading to alternations in diastolic cytosolic Ca2+, RyR2 inactivation, and sarcoplasmic reticulum Ca2+ release (ie, Ca2+ alternans). CONCLUSIONS Our results demonstrate that inactivation of RyR2 by Ca2+-CaM is a major determinant of Ca2+ alternans, making Ca2+-CaM dependent regulation of RyR2 an important therapeutic target for cardiac alternans.
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Affiliation(s)
- Jinhong Wei
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Jinjing Yao
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Darrell Belke
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Wenting Guo
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Xiaowei Zhong
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Bo Sun
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - John Paul Estillore
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
| | - Alexander Vallmitjana
- Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona, Spain (A.V., R.B.)
| | - Raul Benitez
- Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona, Spain (A.V., R.B.).,Institut de Recerca Sant Joan de Déu (IRSJD), Barcelona, Spain (R.B.)
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona IIBB-CSIC, CIBERCV and IIB Sant Pau, Hospital de Sant Pau, Barcelona, Spain (L.H.-M.)
| | - Enrique Alvarez-Lacalle
- Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain (E.A.-L., B.E.)
| | - Blas Echebarria
- Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain (E.A.-L., B.E.)
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Alberta, Canada (J.W., J.Y., D.B., W.G., X.Z., B.S., R.W., J.P.E., S.R.W.C.)
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Protective Effects of Polyphenols against Ischemia/Reperfusion Injury. Molecules 2020; 25:molecules25153469. [PMID: 32751587 PMCID: PMC7435883 DOI: 10.3390/molecules25153469] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/22/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
Myocardial infarction (MI) is a leading cause of morbidity and mortality across the world. It manifests as an imbalance between blood demand and blood delivery in the myocardium, which leads to cardiac ischemia and myocardial necrosis. While it is not easy to identify the first pathogenic cause of MI, the consequences are characterized by ischemia, chronic inflammation, and tissue degeneration. A poor MI prognosis is associated with extensive cardiac remodeling. A loss of viable cardiomyocytes is replaced with fibrosis, which reduces heart contractility and heart function. Recent advances have given rise to the concept of natural polyphenols. These bioactive compounds have been studied for their pharmacological properties and have proven successful in the treatment of cardiovascular diseases. Studies have focused on their various bioactivities, such as their antioxidant and anti-inflammatory effects and free radical scavenging. In this review, we summarized the effects and benefits of polyphenols on the cardiovascular injury, particularly on the treatment of myocardial infarction in animal and human studies.
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9
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Bektik E, Cowan DB, Wang DZ. Long Non-Coding RNAs in Atrial Fibrillation: Pluripotent Stem Cell-Derived Cardiomyocytes as a Model System. Int J Mol Sci 2020; 21:ijms21155424. [PMID: 32751460 PMCID: PMC7432754 DOI: 10.3390/ijms21155424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is a type of sustained arrhythmia in humans often characterized by devastating alterations to the cardiac conduction system as well as the structure of the atria. AF can lead to decreased cardiac function, heart failure, and other complications. Long non-coding RNAs (lncRNAs) have been shown to play important roles in the cardiovascular system, including AF; however, a large group of lncRNAs is not conserved between mouse and human. Furthermore, AF has complex networks showing variations in mechanisms in different species, making it challenging to utilize conventional animal models to investigate the functional roles and potential therapeutic benefits of lncRNAs for AF. Fortunately, pluripotent stem cell (PSC)-derived cardiomyocytes (CMs) offer a reliable platform to study lncRNA functions in AF because of certain electrophysiological and molecular similarities with native human CMs. In this review, we first summarize the broad aspects of lncRNAs in various heart disease settings, then focus on their potential roles in AF development and pathophysiology. We also discuss current uses of PSCs in AF research and describe how these studies could be developed into novel therapeutics for AF and other cardiovascular diseases.
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Affiliation(s)
- Emre Bektik
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood, Boston, MA 02115, USA; (E.B.); (D.B.C.)
| | - Douglas B. Cowan
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood, Boston, MA 02115, USA; (E.B.); (D.B.C.)
| | - Da-Zhi Wang
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood, Boston, MA 02115, USA; (E.B.); (D.B.C.)
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
- Correspondence:
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10
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Intracellular calcium leak in heart failure and atrial fibrillation: a unifying mechanism and therapeutic target. Nat Rev Cardiol 2020; 17:732-747. [PMID: 32555383 DOI: 10.1038/s41569-020-0394-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/06/2020] [Indexed: 12/14/2022]
Abstract
Ca2+ is a fundamental second messenger in all cell types and is required for numerous essential cellular functions, including cardiac and skeletal muscle contraction. The intracellular concentration of free Ca2+ ([Ca2+]) is regulated primarily by ion channels, pumps (ATPases), exchangers and Ca2+-binding proteins. Defective regulation of [Ca2+] is found in a diverse spectrum of pathological states that affect all the major organs. In the heart, abnormalities in the regulation of cytosolic and mitochondrial [Ca2+] occur in heart failure (HF) and atrial fibrillation (AF), two common forms of heart disease and leading contributors to morbidity and mortality. In this Review, we focus on the mechanisms that regulate ryanodine receptor 2 (RYR2), the major sarcoplasmic reticulum (SR) Ca2+-release channel in the heart, how RYR2 becomes dysfunctional in HF and AF, and its potential as a therapeutic target. Inherited RYR2 mutations and/or stress-induced phosphorylation and oxidation of the protein destabilize the closed state of the channel, resulting in a pathological diastolic Ca2+ leak from the SR that both triggers arrhythmias and impairs contractility. On the basis of our increased understanding of SR Ca2+ leak as a shared Ca2+-dependent pathological mechanism in HF and AF, a new class of drugs developed in our laboratory, known as rycals, which stabilize RYR2 channels and prevent Ca2+ leak from the SR, are undergoing investigation in clinical trials.
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Liu T, Xiong F, Qi XY, Xiao J, Villeneuve L, Abu-Taha I, Dobrev D, Huang C, Nattel S. Altered calcium handling produces reentry-promoting action potential alternans in atrial fibrillation-remodeled hearts. JCI Insight 2020; 5:133754. [PMID: 32255765 DOI: 10.1172/jci.insight.133754] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 03/25/2020] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) alters atrial cardiomyocyte (ACM) Ca2+ handling, promoting ectopic beat formation. We examined the effects of AF-associated remodeling on Ca2+-related action potential dynamics and consequences for AF susceptibility. AF was maintained electrically in dogs by right atrial (RA) tachypacing. ACMs isolated from AF dogs showed increased Ca2+ release refractoriness, spontaneous Ca2+ spark frequency, and cycle length (CL) threshold for Ca2+ and action potential duration (APD) alternans versus controls. AF increased the in situ CL threshold for Ca2+/APD alternans and spatial dispersion in Ca2+ release recovery kinetics, leading to spatially discordant alternans associated with reentrant rotor formation and susceptibility to AF induction/maintenance. The clinically available agent dantrolene reduced Ca2+ leak and CL threshold for Ca2+/APD alternans in ACMs and AF dog right atrium, while suppressing AF susceptibility; caffeine increased Ca2+ leak and CL threshold for Ca2+/APD alternans in control dog ACMs and RA tissues. In vivo, the atrial repolarization alternans CL threshold was increased in AF versus control, as was AF vulnerability. Intravenous dantrolene restored repolarization alternans threshold and reduced AF vulnerability. Immunoblots showed reduced expression of total and phosphorylated ryanodine receptors and calsequestrin in AF and unchanged phospholamban/SERCA expression. Thus, along with promoting spontaneous ectopy, AF-induced Ca2+ handling abnormalities favor AF by enhancing vulnerability to repolarization alternans, promoting initiation and maintenance of reentrant activity; dantrolene provides a lead molecule to target this mechanism.
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Affiliation(s)
- Tao Liu
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Cardiology, Renmin Hospital of Wuhan University, China.,Cardiovascular Research Institute, Wuhan University, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Feng Xiong
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Xiao-Yan Qi
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Jiening Xiao
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Louis Villeneuve
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Issam Abu-Taha
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, China.,Cardiovascular Research Institute, Wuhan University, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Stanley Nattel
- Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Germany.,IHU LIRYC Institute, Fondation Bordeaux Université, Bordeaux, France
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12
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Dexamethasone Treatment Increases the Intracellular Calcium Level Through TRPV6 in A549 Cells. Int J Mol Sci 2020; 21:ijms21031050. [PMID: 32033337 PMCID: PMC7037905 DOI: 10.3390/ijms21031050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 12/04/2022] Open
Abstract
This study investigated the effect of dexamethasone (DEX) on intracellular calcium levels and the expressions of transient receptor potential cation channel subcomponent V member 6 (TRPV6), sodium-calcium exchanger 1 (NCX1), and plasma membrane calcium ATPase 1 (PMCA1) in A549 cells. The intracellular calcium level, by using the calcium indicator pGP-CMV-GCaMP6f, increased following DEX treatment for 6, 12, and 24 h in A549 cells. In addition, Rhod-4 assay after DEX treatment for 24 h showed that DEX increased the level of intracellular calcium. The expression of the calcium influx TRPV6 gene significantly increased, whereas the expressions of the calcium outflow NCX1 and PMCA1 genes significantly decreased with DEX treatment. The mRNA levels of surfactant protein genes SFTPA1, SFTPB, SFTPC, and SFTPD and the secreted airway mucin genes MUC1 and MUC5AC were investigated by treating cells with DEX. The DEX treatment decreased the mRNA levels of SFTPA1 and SFTPB but increased the mRNA levels of SFTPC and SFTPD. The MUC1 mRNA level was increased by DEX treatment, whereas MUC5AC mRNA was significantly decreased. These results indicate that DEX influences the intracellular calcium level through TRPV6, and affects pulmonary surfactant genes and secreted airway mucin genes in A549 cells.
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13
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Tanaka H. [Fluorescence imaging of the living heart for understanding the basis of arrhythmias]. Nihon Yakurigaku Zasshi 2019; 154:171-177. [PMID: 31597895 DOI: 10.1254/fpj.154.171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Recent outstanding progress in microscopic imaging technology and the advent of fluorescent probes have enabled us to visualize high spatiotemporal dynamics of intracellular molecules in living tissues. Here I introduce our research outcomes on functional fluorescence imaging of the heart especially for understanding the pathogenesis of cardiac arrhythmias. On the in situ Ca2+ imaging of perfused rat heart by rapid-scanning confocal microscopy, we found that burst emergence of intracellular Ca2+ waves evokes arrhythmogenic triggered activity and subsequent oscillatory depolarizations via the Na+-Ca2+ exchanger. Besides, impairment of Ca2+ release from the sarcoplasmic reticulum leads to emergence of Ca2+ waves and spatiotemporally inhomogeneous Ca2+ dynamics on systole, resulting in beat-to-beat Ca2+ alternans. Such alternating behaviors of Ca2+ dynamics are partly due to poor development of the transverse tubules, which are identified in murine atria and failing ventricular myocytes. In addition, impairment of the gap junctional communication via connexin 43 induced by dominant negative inhibition of neonatal rat ventricular myocyte monolayers results in generation of spiral wave reentry, suggesting the pivotal role of intercellular communications in genesis of arrhythmias. Furthermore, alterations in atrial histoanatomy, e.g., density and arrangements of myocytes and distribution of Cx43, could provide intrinsic arrhythmogenic bases of atrial fibrillation, which was revealed by combined optical imaging of the atria and precise histoanatomical examinations. In combination, fluorescence imaging of the living organisms provides indispensable information for unveiling functions and disease states.
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Affiliation(s)
- Hideo Tanaka
- Department of Pathology and Cell Regulation, Graduate School of Medical Science, Kyoto Prefectural University of Medicine
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14
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Calcium as a Key Player in Arrhythmogenic Cardiomyopathy: Adhesion Disorder or Intracellular Alteration? Int J Mol Sci 2019; 20:ijms20163986. [PMID: 31426283 PMCID: PMC6721231 DOI: 10.3390/ijms20163986] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/08/2019] [Accepted: 08/14/2019] [Indexed: 12/20/2022] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease characterized by sudden death in young people and featured by fibro-adipose myocardium replacement, malignant arrhythmias, and heart failure. To date, no etiological therapies are available. Mutations in desmosomal genes cause abnormal mechanical coupling, trigger pro-apoptotic signaling pathways, and induce fibro-adipose replacement. Here, we discuss the hypothesis that the ACM causative mechanism involves a defect in the expression and/or activity of the cardiac Ca2+ handling machinery, focusing on the available data supporting this hypothesis. The Ca2+ toolkit is heavily remodeled in cardiomyocytes derived from a mouse model of ACM defective of the desmosomal protein plakophilin-2. Furthermore, ACM-related mutations were found in genes encoding for proteins involved in excitation‒contraction coupling, e.g., type 2 ryanodine receptor and phospholamban. As a consequence, the sarcoplasmic reticulum becomes more eager to release Ca2+, thereby inducing delayed afterdepolarizations and impairing cardiac contractility. These data are supported by preliminary observations from patient induced pluripotent stem-cell-derived cardiomyocytes. Assessing the involvement of Ca2+ signaling in the pathogenesis of ACM could be beneficial in the treatment of this life-threatening disease.
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15
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Wang Q, Wang C, Wang B, Shen Q, Qiu L, Zou S, Wang T, Liu G, Wang B, Zhang L. Identification of RyR2-PBmice and the effects of transposon insertional mutagenesis of the RyR2 gene on cardiac function in mice. PeerJ 2019; 7:e6942. [PMID: 31143551 PMCID: PMC6526016 DOI: 10.7717/peerj.6942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/11/2019] [Indexed: 01/01/2023] Open
Abstract
Ryanodine receptor 2 (RyR2) plays an important role in maintaining the normal heart function, and mutantions can lead to arrhythmia, heart failure and other heart diseases. In this study, we successfully identified a piggyBac translocated RyR2 gene heterozygous mouse model (RyR2-PBmice) by tracking red fluorescent protein (RFP) and genotyping PCR. Cardiac function tests showed that there was no significant difference between the RyR2-PBmice and corresponding wild-type mice (WTmice), regardless of whether they were in the basal state or injected with epinephrine and caffeine. However, the sarcoplasmic reticulum Ca2+ content was significantly reduced in the cardiomyocytes of RyR2-PBmice as assessed by measuring caffeine-induced [Ca2+]i transients; the cardiac muscle tissue of RyR2-PBmice displayed significant mitochondrial swelling and focal dissolution of mitochondrial cristae, and the tissue ATP content in the RyR2-PBmice heart was significantly reduced. To further analyze the molecular mechanism behind these changes, we tested the expression levels of related proteins using RT-PCR and Western blot analyses. The mRNA level of RyR2 in RyR2-PBmice cardiac tissue decreased significantly compared with the WTmice, and the protein expression associated with the respiratory chain was also downregulated. These results suggested that the piggyBac transposon inserted into the RyR2 gene substantively affected the structure and function of mitochondria in the mouse cardiomyocytes, leading to disorders of energy metabolism.
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Affiliation(s)
- Qianqian Wang
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Chao Wang
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Bo Wang
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Qirui Shen
- School of Life Sciences, China Jiliang University, Hangzhou, China
| | - Leilei Qiu
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Shuaijun Zou
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Tao Wang
- Department of Nuclear Medicine, Changhai Hospital, Navy Medical University, Shanghai, China
| | - Guoyan Liu
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Beilei Wang
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
| | - Liming Zhang
- Department of Marine Biotechnology, Faculty of Naval Medicine, Navy Medical University, Shanghai, China
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16
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Different adaptive NO-dependent Mechanisms in Normal and Hypertensive Conditions. Molecules 2019; 24:molecules24091682. [PMID: 31052164 PMCID: PMC6539476 DOI: 10.3390/molecules24091682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023] Open
Abstract
Myocardial infarction (MI) remains the leading cause of death worldwide. We aimed to investigate the effect of NO deficiency on selective biochemical parameters within discreet myocardial zones after experimentally induced MI. To induce MI, the left descending coronary artery was ligated in two groups of 16-week-old WKY rats. In one group, NO production was inhibited by L-NAME (20 mg/kg/day) administration four weeks prior to ligation. Sham operations were performed on both groups as a control. Seven days after MI, we evaluated levels of nitric oxide synthase (NOS) activity, eNOS, iNOS, NFҡB/p65 and Nrf2 in ischemic, injured and non-ischemic zones of the heart. Levels of circulating TNF-α and IL-6 were evaluated in the plasma. MI led to increased NOS activity in all investigated zones of myocardium as well as circulating levels of TNF-α and IL-6. L-NAME treatment decreased NOS activity in the heart of sham operated animals. eNOS expression was increased in the injured zone and this could be a compensatory mechanism that improves the perfusion of the myocardium and cardiac dysfunction. Conversely, iNOS expression increased in the infarcted zone and may contribute to the inflammatory process and irreversible necrotic changes.
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17
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Characterization of circRNA‑associated ceRNA networks in patients with nonvalvular persistent atrial fibrillation. Mol Med Rep 2018; 19:638-650. [PMID: 30483740 DOI: 10.3892/mmr.2018.9695] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/13/2018] [Indexed: 11/05/2022] Open
Abstract
Circular RNAs (circRNAs) are non-coding RNAs forming closed-loop structures, and their aberrant expression may lead to disease. However, the potential network of circRNA‑associated competing endogenous RNA (ceRNA) involved in nonvalvular persistent atrial fibrillation (NPAF) has not been previously reported. In the present study, four left atrial appendages (LAA) of patients with NPAF and four normal LAAs were examined via RNA sequencing, and their potential functions were investigated via bioinformatics analysis. The circRNA‑enriched genes were analyzed using Gene Ontology (GO) categories, while the enrichment of circRNAs was detected via the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. A total of 296 significantly dysregulated circRNA transcripts were obtained, with 238 upregulated and 58 downregulated. A number of circRNAs were further confirmed using reverse transcription‑quantitative polymerase chain reaction analysis. Furthermore, the more comprehensive circRNA‑associated ceRNA networks were examined in patients with NPAF. GO categories and KEGG annotation analysis of circRNAs revealed that the circRNA‑associated ceRNA networks were likely to influence AF though alterations in calcium and cardiac muscle contraction. The circRNA‑associated ceRNA networks revealed that dysregulated circRNAs in NPAF may be involved in regulating hsa‑microRNA (miR)‑208b and hsa‑miR‑21. To the best of our knowledge, this study presents the circRNA‑associated ceRNA networks in NPAF for the first time, which may have potential implications for the pathogenesis of AF. This study reveals a potential perspective from which to investigate circRNAs in circRNA‑associated ceRNA networks (hsa_circRNA002085, hsa_circRNA001321) in NPAF, and provides a potential biomarker for AF.
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18
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Shangguan W, Liang X, Shi W, Liu T, Wang M, Li G. Identification and characterization of circular RNAs in rapid atrial pacing dog atrial tissue. Biochem Biophys Res Commun 2018; 506:1-6. [PMID: 29772236 DOI: 10.1016/j.bbrc.2018.05.082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 05/13/2018] [Indexed: 12/11/2022]
Abstract
Circular RNAs (circRNAs) have emerged as novel molecules of interest in gene regulation as other noncoding RNAs, and participating in the process of many diseases. However, the expression and functions of circRNAs in Rapid atrial pacing (RAP) dog atrial tissue still unknown. 12 canines were randomly assigned to control and pacing group. RAP at 500 beats per minute was maintained 14 days in the pacing group. The expression characterization of circRNAs were revealed by high-throughput sequencing. We totally predicted 15,990 circRNAs in dog atrial tissues. Moreover, we found 146 differentially expressed circRNAs between control and RAP dogs. Five circRNAs were selected for subsequent RT-PCR validation, and four circRNAs confirmed with the high throughput sequencing analysis. GO analysis showed that the differentially expressed circRNAs might involve in the process of "structural constituent of cytoskeleton, ion channel activity". We explored the circRNA-miRNA interaction network, and found extensive interaction among differentially expressed circRNAs and AF related miRNAs and mRNAs. Our work firstly identified the characterization of circRNAs in the dog atrial, and revealed the differentially expressed circRNAs in the RAP dog, this might lay a solid foundation on the function of circRNA in the mechanisms of AF.
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Affiliation(s)
- Wenfeng Shangguan
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Xue Liang
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Wen Shi
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Manman Wang
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Guangping Li
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China.
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19
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Kushnir A, Wajsberg B, Marks AR. Ryanodine receptor dysfunction in human disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1687-1697. [PMID: 30040966 DOI: 10.1016/j.bbamcr.2018.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/07/2023]
Abstract
Regulation of intracellular calcium (Ca2+) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca2+ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca2+ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca2+ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Medicine, Division of Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Benjamin Wajsberg
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
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20
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Sun B, Wei J, Zhong X, Guo W, Yao J, Wang R, Vallmitjana A, Benitez R, Hove-Madsen L, Chen SRW. The cardiac ryanodine receptor, but not sarcoplasmic reticulum Ca 2+-ATPase, is a major determinant of Ca 2+ alternans in intact mouse hearts. J Biol Chem 2018; 293:13650-13661. [PMID: 29986885 DOI: 10.1074/jbc.ra118.003760] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/06/2018] [Indexed: 11/06/2022] Open
Abstract
Sarcoplasmic reticulum (SR) Ca2+ cycling is governed by the cardiac ryanodine receptor (RyR2) and SR Ca2+-ATPase (SERCA2a). Abnormal SR Ca2+ cycling is thought to be the primary cause of Ca2+ alternans that can elicit ventricular arrhythmias and sudden cardiac arrest. Although alterations in either RyR2 or SERCA2a function are expected to affect SR Ca2+ cycling, whether and to what extent altered RyR2 or SERCA2a function affects Ca2+ alternans is unclear. Here, we employed a gain-of-function RyR2 variant (R4496C) and the phospholamban-knockout (PLB-KO) mouse model to assess the effect of genetically enhanced RyR2 or SERCA2a function on Ca2+ alternans. Confocal Ca2+ imaging revealed that RyR2-R4496C shortened SR Ca2+ release refractoriness and markedly suppressed rapid pacing-induced Ca2+ alternans. Interestingly, despite enhancing RyR2 function, intact RyR2-R4496C hearts exhibited no detectable spontaneous SR Ca2+ release events during pacing. Unlike for RyR2, enhancing SERCA2a function by ablating PLB exerted a relatively minor effect on Ca2+ alternans in intact hearts expressing RyR2 WT or a loss-of-function RyR2 variant, E4872Q, that promotes Ca2+ alternans. Furthermore, partial SERCA2a inhibition with 3 μm 2,5-di-tert-butylhydroquinone (tBHQ) also had little impact on Ca2+ alternans, whereas strong SERCA2a inhibition with 10 μm tBHQ markedly reduced the amplitude of Ca2+ transients and suppressed Ca2+ alternans in intact hearts. Our results demonstrate that enhanced RyR2 function suppresses Ca2+ alternans in the absence of spontaneous Ca2+ release and that RyR2, but not SERCA2a, is a key determinant of Ca2+ alternans in intact working hearts, making RyR2 an important therapeutic target for cardiac alternans.
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Affiliation(s)
- Bo Sun
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Jinhong Wei
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Xiaowei Zhong
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Wenting Guo
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Jinjing Yao
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Alexander Vallmitjana
- the Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona 08034, Spain, and
| | - Raul Benitez
- the Department of Automatic Control, Universitat Politècnica de Catalunya, Barcelona 08034, Spain, and
| | - Leif Hove-Madsen
- the Biomedical Research Institute of Barcelona (IIBB), CSIC, Sant Pau, Hospital de Sant Pau, Barcelona 08025, Spain
| | - S R Wayne Chen
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada,
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21
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Santulli G, Lewis D, des Georges A, Marks AR, Frank J. Ryanodine Receptor Structure and Function in Health and Disease. Subcell Biochem 2018; 87:329-352. [PMID: 29464565 PMCID: PMC5936639 DOI: 10.1007/978-981-10-7757-9_11] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ryanodine receptors (RyRs) are ubiquitous intracellular calcium (Ca2+) release channels required for the function of many organs including heart and skeletal muscle, synaptic transmission in the brain, pancreatic beta cell function, and vascular tone. In disease, defective function of RyRs due either to stress (hyperadrenergic and/or oxidative overload) or genetic mutations can render the channels leaky to Ca2+ and promote defective disease-causing signals as observed in heat failure, muscular dystrophy, diabetes mellitus, and neurodegerative disease. RyRs are massive structures comprising the largest known ion channel-bearing macromolecular complex and exceeding 3 million Daltons in molecular weight. RyRs mediate the rapid release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) to stimulate cellular functions through Ca2+-dependent processes. Recent advances in single-particle cryogenic electron microscopy (cryo-EM) have enabled the determination of atomic-level structures for RyR for the first time. These structures have illuminated the mechanisms by which these critical ion channels function and interact with regulatory ligands. In the present chapter we discuss the structure, functional elements, gating and activation mechanisms of RyRs in normal and disease states.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, USA
- The Wilf Family Cardiovascular Research Institute and the Einstein-Mount Sinai Diabetes Research Center, Department of Medicine, Albert Einstein College of Medicine - Montefiore University Hospital, New York, NY, USA
| | - Daniel Lewis
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Amedee des Georges
- Advanced Science Research Center at the Graduate Center of the City University of New York, New York, NY, USA
- Department of Chemistry & Biochemistry, City College of New York, New York, NY, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Medicine, Columbia University, New York, NY, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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22
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Sirolimus induces depletion of intracellular calcium stores and mitochondrial dysfunction in pancreatic beta cells. Sci Rep 2017; 7:15823. [PMID: 29158477 PMCID: PMC5696524 DOI: 10.1038/s41598-017-15283-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/20/2017] [Indexed: 12/19/2022] Open
Abstract
Sirolimus (rapamycin) is an immunosuppressive drug used in transplantation. One of its major side effects is the increased risk of diabetes mellitus; however, the exact mechanisms underlying such association have not been elucidated. Here we show that sirolimus impairs glucose-stimulated insulin secretion both in human and murine pancreatic islets and in clonal β cells in a dose- and time-dependent manner. Importantly, we demonstrate that sirolimus markedly depletes calcium (Ca2+) content in the endoplasmic reticulum and significantly decreases glucose-stimulated mitochondrial Ca2+ uptake. Crucially, the reduced mitochondrial Ca2+ uptake is mirrored by a significant impairment in mitochondrial respiration. Taken together, our findings indicate that sirolimus causes depletion of intracellular Ca2+ stores and alters mitochondrial fitness, eventually leading to decreased insulin release. Our results provide a novel molecular mechanism underlying the increased incidence of diabetes mellitus in patients treated with this drug.
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23
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Impaired mitochondrial calcium uptake caused by tacrolimus underlies beta-cell failure. Cell Commun Signal 2017; 15:47. [PMID: 29132395 PMCID: PMC5684747 DOI: 10.1186/s12964-017-0203-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/02/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND One of the most common side effects of the immunosuppressive drug tacrolimus (FK506) is the increased risk of new-onset diabetes mellitus. However, the molecular mechanisms underlying this association have not been fully clarified. METHODS We studied the effects of the therapeutic dose of tacrolimus on mitochondrial fitness in beta-cells. RESULTS We demonstrate that tacrolimus impairs glucose-stimulated insulin secretion (GSIS) in beta-cells through a previously unidentified mechanism. Indeed, tacrolimus causes a decrease in mitochondrial Ca2+ uptake, accompanied by altered mitochondrial respiration and reduced ATP production, eventually leading to impaired GSIS. CONCLUSION Our observations individuate a new fundamental mechanism responsible for the augmented incidence of diabetes following tacrolimus treatment. Indeed, this drug alters Ca2+ fluxes in mitochondria, thereby compromising metabolism-secretion coupling in beta-cells.
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Gambardella J, Sorriento D, Ciccarelli M, Del Giudice C, Fiordelisi A, Napolitano L, Trimarco B, Iaccarino G, Santulli G. Functional Role of Mitochondria in Arrhythmogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:191-202. [PMID: 28551788 DOI: 10.1007/978-3-319-55330-6_10] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Growing evidence indicate that mitochondria play a functional role in arrhythmogenesis. We report here the molecular mechanisms underlying the action of these highly dynamic organelles in the regulation of cell metabolism, action potential and, overall, heart excitability. In particular, we examine the role of cardiac mitochondria in linking metabolism and cell excitability. The importance of the main mitochondrial channels is evaluated as well, including the recently identified calcium uniporter. Promises and pitfalls of potential therapeutic strategies targeting mitochondrial pathways are also assessed.
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Affiliation(s)
- Jessica Gambardella
- Columbia University Medical Center, New York, NY, USA.,Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Daniela Sorriento
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Michele Ciccarelli
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Carmine Del Giudice
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Antonella Fiordelisi
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Luigi Napolitano
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Bruno Trimarco
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Guido Iaccarino
- Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Italy
| | - Gaetano Santulli
- Dept. of Biomedical Advanced Sciences, Federico II University, Naples, Italy. .,Columbia University Medical Center, New York Presbyterian Hospital-Manhattan, New York, NY, USA.
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25
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Dynamics of spatiotemporal line defects and chaos control in complex excitable systems. Sci Rep 2017; 7:7757. [PMID: 28798384 PMCID: PMC5552747 DOI: 10.1038/s41598-017-08011-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/30/2017] [Indexed: 12/01/2022] Open
Abstract
Spatiotemporal pattern formation governs dynamics and functions in various biological systems. In the heart, excitable waves can form complex oscillatory and chaotic patterns even at an abnormally higher frequency than normal heart beats, which increase the risk of fatal heart conditions by inhibiting normal blood circulation. Previous studies suggested that line defects (nodal lines) play a critical role in stabilizing those undesirable patterns. However, it remains unknown if the line defects are static or dynamically changing structures in heart tissue. Through in vitro experiments of heart tissue observation, we reveal the spatiotemporal dynamics of line defects in rotating spiral waves. We combined a novel signaling over-sampling technique with a multi-dimensional Fourier analysis, showing that line defects can translate, merge, collapse and form stable singularities with even and odd parity while maintaining a stable oscillation of the spiral wave in the tissue. These findings provide insights into a broad class of complex periodic systems, with particular impact to the control and understanding of heart diseases.
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Abstract
There has been a significant progress in our understanding of the molecular mechanisms by which calcium (Ca2+) ions mediate various types of cardiac arrhythmias. A growing list of inherited gene defects can cause potentially lethal cardiac arrhythmia syndromes, including catecholaminergic polymorphic ventricular tachycardia, congenital long QT syndrome, and hypertrophic cardiomyopathy. In addition, acquired deficits of multiple Ca2+-handling proteins can contribute to the pathogenesis of arrhythmias in patients with various types of heart disease. In this review article, we will first review the key role of Ca2+ in normal cardiac function-in particular, excitation-contraction coupling and normal electric rhythms. The functional involvement of Ca2+ in distinct arrhythmia mechanisms will be discussed, followed by various inherited arrhythmia syndromes caused by mutations in Ca2+-handling proteins. Finally, we will discuss how changes in the expression of regulation of Ca2+ channels and transporters can cause acquired arrhythmias, and how these mechanisms might be targeted for therapeutic purposes.
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Affiliation(s)
- Andrew P Landstrom
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.)
| | - Dobromir Dobrev
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.)
| | - Xander H T Wehrens
- From the Section of Cardiology, Department of Pediatrics (A.P.L.), Cardiovascular Research Institute (A.P.L., X.H.T.W.), and Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX; and Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany (D.D.).
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27
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Nitrite-Nitric Oxide Signaling and Cardioprotection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:335-346. [DOI: 10.1007/978-3-319-55330-6_18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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28
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Altered long non-coding RNA expression profile in rabbit atria with atrial fibrillation: TCONS_00075467 modulates atrial electrical remodeling by sponging miR-328 to regulate CACNA1C. J Mol Cell Cardiol 2017; 108:73-85. [PMID: 28546098 DOI: 10.1016/j.yjmcc.2017.05.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 02/01/2023]
Abstract
Electrical remodeling has been reported to play a major role in the initiation and maintenance of atrial fibrillation (AF). Long non-coding RNAs (lncRNAs) have been increasingly recognized as contributors to the pathology of heart diseases. However, the roles and mechanisms of lncRNAs in electrical remodeling during AF remain unknown. In this study, the lncRNA expression profiles of right atria were investigated in AF and non-AF rabbit models by using RNA sequencing technique and validated using quantitative real-time polymerase chain reaction (qRT-PCR). A total of 99,843 putative new lncRNAs were identified, in which 1220 differentially expressed transcripts exhibited >2-fold change. Bioinformatics analysis was conducted to predict the functions and interactions of the aberrantly expressed genes. On the basis of a series of filtering pipelines, one lncRNA, TCONS_00075467, was selected to explore its effects and mechanisms on electrical remodeling. The atrial effective refractory period was shortened in vivo and the L-type calcium current and action potential duration were decreased in vitro by silencing of TCONS_00075467 with lentiviruses. Besides, the expression of miRNA-328 was negatively correlated with TCONS_00075467. We further demonstrated that TCONS_00075467 could sponge miRNA-328 in vitro and in vivo to regulate the downstream protein coding gene CACNA1C. In addition, miRNA-328 could partly reverse the effects of TCONS_00075467 on electrical remodeling. In summary, dysregulated lncRNAs may play important roles in modulating electrical remodeling during AF. Our study may facilitate the mechanism studies of lncRNAs in AF pathogenesis and provide potential therapeutic targets for AF.
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29
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Santulli G, Nakashima R, Yuan Q, Marks AR. Intracellular calcium release channels: an update. J Physiol 2017; 595:3041-3051. [PMID: 28303572 PMCID: PMC5430224 DOI: 10.1113/jp272781] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 02/20/2017] [Indexed: 12/19/2022] Open
Abstract
Ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3 Rs) are calcium (Ca2+ ) release channels on the endo/sarcoplasmic reticulum (ER/SR). Here we summarize the latest advances in the field, describing the recently discovered mechanistic roles of intracellular Ca2+ release channels in the regulation of mitochondrial fitness and endothelial function, providing novel therapeutic options for the treatment of heart failure, hypertension, and diabetes mellitus.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular CardiologyColumbia UniversityNew YorkNYUSA
- Department of Physiology and Cellular BiophysicsCollege of Physicians and SurgeonsColumbia University Medical CenterNew YorkNYUSA
| | - Ryutaro Nakashima
- The Wu Center for Molecular CardiologyColumbia UniversityNew YorkNYUSA
- Department of Physiology and Cellular BiophysicsCollege of Physicians and SurgeonsColumbia University Medical CenterNew YorkNYUSA
| | - Qi Yuan
- The Wu Center for Molecular CardiologyColumbia UniversityNew YorkNYUSA
- Department of Physiology and Cellular BiophysicsCollege of Physicians and SurgeonsColumbia University Medical CenterNew YorkNYUSA
| | - Andrew R. Marks
- The Wu Center for Molecular CardiologyColumbia UniversityNew YorkNYUSA
- Department of Physiology and Cellular BiophysicsCollege of Physicians and SurgeonsColumbia University Medical CenterNew YorkNYUSA
- Department of MedicineColumbia UniversityNew YorkNYUSA
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Santulli G, Lewis DR, Marks AR. Physiology and pathophysiology of excitation-contraction coupling: the functional role of ryanodine receptor. J Muscle Res Cell Motil 2017; 38:37-45. [PMID: 28653141 PMCID: PMC5813681 DOI: 10.1007/s10974-017-9470-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022]
Abstract
Calcium (Ca2+) release from intracellular stores plays a key role in the regulation of skeletal muscle contraction. The type 1 ryanodine receptors (RyR1) is the major Ca2+ release channel on the sarcoplasmic reticulum (SR) of myocytes in skeletal muscle and is required for excitation-contraction (E-C) coupling. This article explores the role of RyR1 in skeletal muscle physiology and pathophysiology.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Daniel R Lewis
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Andrew R Marks
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA.
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA.
- Department of Medicine, Columbia University, New York, NY, USA.
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31
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Gambardella J, Trimarco B, Iaccarino G, Santulli G. New Insights in Cardiac Calcium Handling and Excitation-Contraction Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1067:373-385. [PMID: 28956314 DOI: 10.1007/5584_2017_106] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Excitation-contraction (EC) coupling denotes the conversion of electric stimulus in mechanic output in contractile cells. Several studies have demonstrated that calcium (Ca2+) plays a pivotal role in this process. Here we present a comprehensive and updated description of the main systems involved in cardiac Ca2+ handling that ensure a functional EC coupling and their pathological alterations, mainly related to heart failure.
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Affiliation(s)
- Jessica Gambardella
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy.,Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno, Fisciano, Italy
| | - Bruno Trimarco
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy
| | - Guido Iaccarino
- Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno, Fisciano, Italy
| | - Gaetano Santulli
- Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy. .,Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Forch 525, 10461, New York, NY, USA.
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32
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Mitochondria and Cardiac Hypertrophy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:203-226. [DOI: 10.1007/978-3-319-55330-6_11] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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33
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Mechanisms of arrhythmogenesis related to calcium-driven alternans in a model of human atrial fibrillation. Sci Rep 2016; 6:36395. [PMID: 27812021 PMCID: PMC5095679 DOI: 10.1038/srep36395] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/11/2016] [Indexed: 11/08/2022] Open
Abstract
The occurrence of atrial fibrillation (AF) is associated with progressive changes in the calcium handling system of atrial myocytes. Calcium cycling instability has been implicated as an underlying mechanism of electrical alternans observed in patients who experience AF. However, the extent to which calcium-induced alternation of electrical activity in the atria contributes to arrhythmogenesis is unknown. In this study, we investigated the effects of calcium-driven alternans (CDA) on arrhythmia susceptibility in a biophysically detailed, 3D computer model of the human atria representing electrical and structural remodeling secondary to chronic AF. We found that elevated propensity to CDA rendered the atria vulnerable to ectopy-induced arrhythmia. It also increased the complexity and persistence of arrhythmias induced by fast pacing, with unstable scroll waves meandering and frequently breaking up to produce multiple wavelets. Our results suggest that calcium-induced electrical instability may increase arrhythmia vulnerability and promote increasing disorganization of arrhythmias in the chronic AF-remodeled atria, thus playing an important role in the progression of the disease.
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34
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Santulli G, Iaccarino G. Adrenergic signaling in heart failure and cardiovascular aging. Maturitas 2016; 93:65-72. [PMID: 27062709 PMCID: PMC5036981 DOI: 10.1016/j.maturitas.2016.03.022] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 03/23/2016] [Accepted: 03/25/2016] [Indexed: 12/15/2022]
Abstract
Both cardiovascular disease and aging are associated with changes in the sympathetic nervous system. Indeed, mounting evidence indicates that adrenergic receptors are functionally involved in numerous processes underlying both aging and cardiovascular disorders, in particular heart failure. This article will review the pathophysiological role of the sympathetic nervous system in heart failure and cardiovascular aging.
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Affiliation(s)
- Gaetano Santulli
- College of Physicians & Surgeons, Columbia University Medical Center, New York, NY, USA.
| | - Guido Iaccarino
- Division of Internal Medicine, Department of Medicine and Surgery, University of Salerno, Italy.
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35
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Calcium Handling Abnormalities as a Target for Atrial Fibrillation Therapeutics: How Close to Clinical Implementation? J Cardiovasc Pharmacol 2016; 66:515-22. [PMID: 25830486 DOI: 10.1097/fjc.0000000000000253] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia with a substantial impact on morbidity and mortality. Antiarrhythmic drugs play a major role in rhythm-control therapy of AF. However, currently available agents exhibit limited efficacy and pronounced adverse effects, notably drug-induced proarrhythmia. Recent experimental studies have identified that Ca handling abnormalities are critical elements in AF pathophysiology with central roles in atrial ectopic activity, reentry, and atrial remodeling suggesting that Ca handling abnormalities could be promising targets for novel AF therapeutics. Here, we summarize key aspects of AF-related Ca-handling abnormalities, describe currently available compounds targeting atrial Ca handling, and highlight potential novel targets and experimental drugs currently under investigation. Finally, we assess how close AF therapeutics based on Ca-handling abnormalities are to clinical implementation.
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36
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Tse G, Yan BP, Chan YWF, Tian XY, Huang Y. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis. Front Physiol 2016; 7:313. [PMID: 27536244 PMCID: PMC4971160 DOI: 10.3389/fphys.2016.00313] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/11/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. METHOD A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. RESULTS Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. CONCLUSION ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
| | - Yin W. F. Chan
- Department of Psychology, School of Biological Sciences, University of CambridgeCambridge, UK
| | - Xiao Yu Tian
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
| | - Yu Huang
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
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37
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Maintenance of normal blood pressure is dependent on IP3R1-mediated regulation of eNOS. Proc Natl Acad Sci U S A 2016; 113:8532-7. [PMID: 27402766 DOI: 10.1073/pnas.1608859113] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Endothelial cells (ECs) are critical mediators of blood pressure (BP) regulation, primarily via the generation and release of vasorelaxants, including nitric oxide (NO). NO is produced in ECs by endothelial NO synthase (eNOS), which is activated by both calcium (Ca(2+))-dependent and independent pathways. Here, we report that intracellular Ca(2+) release from the endoplasmic reticulum (ER) via inositol 1,4,5-trisphosphate receptor (IP3R) is required for Ca(2+)-dependent eNOS activation. EC-specific type 1 1,4,5-trisphosphate receptor knockout (IP3R1(-/-)) mice are hypertensive and display blunted vasodilation in response to acetylcholine (ACh). Moreover, eNOS activity is reduced in both isolated IP3R1-deficient murine ECs and human ECs following IP3R1 knockdown. IP3R1 is upstream of calcineurin, a Ca(2+)/calmodulin-activated serine/threonine protein phosphatase. We show here that the calcineurin/nuclear factor of activated T cells (NFAT) pathway is less active and eNOS levels are decreased in IP3R1-deficient ECs. Furthermore, the calcineurin inhibitor cyclosporin A, whose use has been associated with the development of hypertension, reduces eNOS activity and vasodilation following ACh stimulation. Our results demonstrate that IP3R1 plays a crucial role in the EC-mediated vasorelaxation and the maintenance of normal BP.
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38
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Hormone replacement therapy and risk of atrial fibrillation in Taiwanese menopause women: A nationwide cohort study. Sci Rep 2016; 6:24132. [PMID: 27052889 PMCID: PMC4823790 DOI: 10.1038/srep24132] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/21/2016] [Indexed: 01/23/2023] Open
Abstract
Hormone replacement therapy (HRT) is associated with risk of vascular disease. The association between atrial fibrillation (AF), vascular events, and different HRTs, including estradiol and conjugated equine estrogens (CEE), has been controversial in previous studies. Thus, we conducted a retrospective cohort study to investigate these associations. Female patients (>45 years old) first diagnosed with menopause were enrolled from National Health Insurance Research Dataset (1998–2008). Cox regression analysis estimated risk of new-onset AF, stroke, and major adverse cardiac events (MACE) after exposure to estradiol or CEE. Of 5489 females (mean age = 55 years) enrolled, 1815 treated with estradiol and 3674 treated with CEE. Incidence per 103 person-years of AF, stroke, and MACE in CEE vs estradiol patients was 2.23 vs. 0.92, 14.0 vs. 9.09, and 15.55 vs. 10.47. As compared with patients treated with estradiol, those treated with CEE had a significantly higher incidence of AF, stroke, and MACE. The adjusted hazard ratios for each category were 1.96, 1.30, and 1.26, respectively. The significant results remained similar, even after use of propensity-score-matched strategy. In conclusion, CEE was associated with a higher risk of AF, stroke, and MACE than estradiol in menopausal females. Further exploration of underlying mechanisms is necessary.
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Abstract
Digoxin has long been used for rate control in atrial fibrillation (AF); its safety remains controversial.We performed a literature search using MEDLINE (source PubMed, January 1, 1966, to July 31, 2015) and EMBASE (January 1, 1980, to July 31, 2015) with no restrictions. Studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Pooled effect estimates were obtained by using random-effects meta-analysis.Twenty-two studies involving 586,594 patients were identified. Patients taking digoxin, as compared with those who took no digoxin, experienced an increased risk of death from any cause (RR: 1.29[95% CI 1.16-1.43]), even after reported adjustment for propensity scores (RR: 1.28[95% CI 1.18-1.39]). The risk of death was increased with patients with or without heart failure (RR: 1.12[95% CI 1.02-1.23] and RR: 1.26[95% CI 1.15-1.29], respectively), and patients taking or not taking beta blockers (RR: 1.17 [95% CI 1.06-1.30] and RR: 1.28 [95% CI 1.08-1.51], respectively). Digoxin use was also associated with increased risk of cardiovascular death (RR: 1.32 [95% CI 1.07-1.64]), arrhythmic death (RR: 1.38 [95% CI 1.07-1.79]), and stroke (RR: 1.20 [95% CI 1.004-1.44]). Digoxin treatment is associated with an absolute risk increase of 19 (95% CI 13-26) additional deaths from any cause per 1000 person-years.Digoxin use is associated with a significant increased risk for death from any cause in patients with AF. This finding suggests a need for reconsideration of present treatment recommendations on use of digoxin in AF.
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Affiliation(s)
- Wu-Tao Zeng
- From the Department of Cardiology (W-TZ, Y-JC), the Eastern Hospital of the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China; Department of Emergency (Z-HL), the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China; Department of Obstetrics and Gynecology (Z-YL), the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China; Department of Cardiology (MZ), Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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Zile MA, Trayanova NA. Rate-dependent force, intracellular calcium, and action potential voltage alternans are modulated by sarcomere length and heart failure induced-remodeling of thin filament regulation in human heart failure: A myocyte modeling study. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:270-80. [PMID: 26724571 DOI: 10.1016/j.pbiomolbio.2015.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/24/2015] [Accepted: 12/23/2015] [Indexed: 01/26/2023]
Abstract
Microvolt T-wave alternans (MTWA) testing identifies heart failure patients at risk for lethal ventricular arrhythmias at near-resting heart rates (<110 beats per minute). Since pressure alternans occurs simultaneously with MTWA and has a higher signal to noise ratio, it may be a better predictor of arrhythmia, although the mechanism remains unknown. Therefore, we investigated the relationship between force alternans (FORCE-ALT), the cellular manifestation of pressure alternans, and action potential voltage alternans (APV-ALT), the cellular driver of MTWA. Our goal was to uncover the mechanisms linking APV-ALT and FORCE-ALT in failing human myocytes and to investigate how the link between those alternans was affected by pacing rate and by physiological conditions such as sarcomere length and heart failure induced-remodeling of mechanical parameters. To achieve this, a mechanically-based, strongly coupled human electromechanical myocyte model was constructed. Reducing the sarcoplasmic reticulum calcium uptake current (Iup) to 27% was incorporated to simulate abnormal calcium handling in human heart failure. Mechanical remodeling was incorporated to simulate altered thin filament activation and crossbridge (XB) cycling rates. A dynamical pacing protocol was used to investigate the development of intracellular calcium concentration ([Ca]i), voltage, and active force alternans at different pacing rates. FORCE-ALT only occurred in simulations incorporating reduced Iup, demonstrating that alternans in the intracellular calcium concentration (CA-ALT) induced FORCE-ALT. The magnitude of FORCE-ALT was found to be largest at clinically relevant pacing rates (<110 bpm), where APV-ALT was smallest. We found that the magnitudes of FORCE-ALT, CA-ALT and APV-ALT were altered by heart failure induced-remodeling of mechanical parameters and sarcomere length due to the presence of myofilament feedback. These findings provide important insight into the relationship between heart-failure-induced electrical and mechanical alternans and how they are altered by physiological conditions at near-resting heart rates.
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Affiliation(s)
- Melanie A Zile
- Institute for Computational Medicine and Department of Biomedical Engineering at Johns Hopkins University, 3400N Charles St, 316 Hackerman Hall, Baltimore, MD 21218, USA.
| | - Natalia A Trayanova
- Institute for Computational Medicine and Department of Biomedical Engineering at Johns Hopkins University, 3400N Charles St, 316 Hackerman Hall, Baltimore, MD 21218, USA.
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41
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A comparison of fluorescent Ca²⁺ indicators for imaging local Ca²⁺ signals in cultured cells. Cell Calcium 2015; 58:638-48. [PMID: 26572560 DOI: 10.1016/j.ceca.2015.10.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/05/2015] [Accepted: 10/26/2015] [Indexed: 11/23/2022]
Abstract
Localized subcellular changes in Ca(2+) serve as important cellular signaling elements, regulating processes as diverse as neuronal excitability and gene expression. Studies of cellular Ca(2+) signaling have been greatly facilitated by the availability of fluorescent Ca(2+) indicators. The respective merits of different indicators to monitor bulk changes in cellular Ca(2+) levels have been widely evaluated, but a comprehensive comparison for their use in detecting and analyzing local, subcellular Ca(2+) signals is lacking. Here, we evaluated several fluorescent Ca(2+) indicators in the context of local Ca(2+) signals (puffs) evoked by inositol 1,4,5-trisphosphate (IP3) in cultured human neuroblastoma SH-SY5Y cells, using high-speed video-microscopy. Altogether, nine synthetic Ca(2+) dyes (Fluo-4, Fluo-8, Fluo-8 high affinity, Fluo-8 low affinity, Oregon Green BAPTA-1, Cal-520, Rhod-4, Asante Calcium Red, and X-Rhod-1) and three genetically-encoded Ca(2+)-indicators (GCaMP6-slow, -medium and -fast variants) were tested; criteria include the magnitude, kinetics, signal-to-noise ratio and detection efficiency of local Ca(2+) puffs. Among these, we conclude that Cal-520 is the optimal indicator for detecting and faithfully tracking local events; that Rhod-4 is the red-emitting indicator of choice; and that none of the GCaMP6 variants are well suited for imaging subcellular Ca(2+) signals.
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Nassal MMJ, Wan X, Laurita KR, Cutler MJ. Atrial SERCA2a Overexpression Has No Affect on Cardiac Alternans but Promotes Arrhythmogenic SR Ca2+ Triggers. PLoS One 2015; 10:e0137359. [PMID: 26352986 PMCID: PMC4564245 DOI: 10.1371/journal.pone.0137359] [Citation(s) in RCA: 9] [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: 06/04/2015] [Accepted: 08/14/2015] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in humans, yet; treatment has remained sub-optimal due to poor understanding of the underlying mechanisms. Cardiac alternans precede AF episodes, suggesting an important arrhythmia substrate. Recently, we demonstrated ventricular SERCA2a overexpression suppresses cardiac alternans and arrhythmias. Therefore, we hypothesized that atrial SERCA2a overexpression will decrease cardiac alternans and arrhythmias. METHODS Adult rat isolated atrial myocytes where divided into three treatment groups 1) Control, 2) SERCA2a overexpression (Ad.SERCA2a) and 3) SERCA2a inhibition (Thapsigargin, 1μm). Intracellular Ca2+ was measured using Indo-1AM and Ca2+ alternans (Ca-ALT) was induced with a standard ramp pacing protocol. RESULTS As predicted, SR Ca2+ reuptake was enhanced with SERCA2a overexpression (p< 0.05) and reduced with SERCA2a inhibition (p<0.05). Surprisingly, there was no difference in susceptibility to Ca-ALT with either SERCA2a overexpression or inhibition when compared to controls (p = 0.73). In contrast, SERCA2a overexpression resulted in increased premature SR Ca2+ (SCR) release compared to control myocytes (28% and 0%, p < 0.05) and concomitant increase in SR Ca2+ load (p<0.05). Based on these observations we tested in-vivo atrial arrhythmia inducibility in control and Ad.SERCA2a animals using an esophageal atrial burst pacing protocol. There were no inducible atrial arrhythmias in Ad.GFP (n = 4) animals though 20% of Ad.SERCA2a (n = 5) animals had inducible atrial arrhythmias (p = 0.20). CONCLUSIONS Our findings suggest that unlike the ventricle, SERCA2a is not a key regulator of cardiac alternans in the atrium. Importantly, SERCA2a overexpression in atrial myocytes can increase SCR, which may be arrhythmogenic.
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Affiliation(s)
- Michelle M. J. Nassal
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States of America
| | - Xiaoping Wan
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, OH, United States of America
| | - Kenneth R. Laurita
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, OH, United States of America
| | - Michael J. Cutler
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, OH, United States of America
- Intermountain Heart Institute, Salt Lake City, Utah, United States of America
- * E-mail:
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Abstract
Calcium (Ca2+) released from the sarcoplasmic reticulum (SR) is crucial for excitation-contraction (E-C) coupling. Mitochondria, the major source of energy, in the form of ATP, required for cardiac contractility, are closely interconnected with the SR, and Ca2+ is essential for optimal function of these organelles. However, Ca2+ accumulation can impair mitochondrial function, leading to reduced ATP production and increased release of reactive oxygen species (ROS). Oxidative stress contributes to heart failure (HF), but whether mitochondrial Ca2+ plays a mechanistic role in HF remains unresolved. Here, we show for the first time, to our knowledge, that diastolic SR Ca2+ leak causes mitochondrial Ca2+ overload and dysfunction in a murine model of postmyocardial infarction HF. There are two forms of Ca2+ release channels on cardiac SR: type 2 ryanodine receptors (RyR2s) and type 2 inositol 1,4,5-trisphosphate receptors (IP3R2s). Using murine models harboring RyR2 mutations that either cause or inhibit SR Ca2+ leak, we found that leaky RyR2 channels result in mitochondrial Ca2+ overload, dysmorphology, and malfunction. In contrast, cardiac-specific deletion of IP3R2 had no major effect on mitochondrial fitness in HF. Moreover, genetic enhancement of mitochondrial antioxidant activity improved mitochondrial function and reduced posttranslational modifications of RyR2 macromolecular complex. Our data demonstrate that leaky RyR2, but not IP3R2, channels cause mitochondrial Ca2+ overload and dysfunction in HF.
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Mitochondrial oxidative stress promotes atrial fibrillation. Sci Rep 2015; 5:11427. [PMID: 26169582 PMCID: PMC4501003 DOI: 10.1038/srep11427] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/26/2015] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress has been suggested to play a role in the pathogenesis of atrial fibrillation (AF). Indeed, the prevalence of AF increases with age as does oxidative stress. However, the mechanisms linking redox state to AF are not well understood. In this study we identify a link between oxidative stress and aberrant intracellular Ca2+ release via the type 2 ryanodine receptor (RyR2) that promotes AF. We show that RyR2 are oxidized in the atria of patients with chronic AF compared with individuals in sinus rhythm. To dissect the molecular mechanism linking RyR2 oxidation to AF we used two murine models harboring RyR2 mutations that cause intracellular Ca2+ leak. Mice with intracellular Ca2+ leak exhibited increased atrial RyR2 oxidation, mitochondrial dysfunction, reactive oxygen species (ROS) production and AF susceptibility. Both genetic inhibition of mitochondrial ROS production and pharmacological treatment of RyR2 leakage prevented AF. Collectively, our results indicate that alterations of RyR2 and mitochondrial ROS generation form a vicious cycle in the development of AF. Targeting this previously unrecognized mechanism could be useful in developing effective interventions to prevent and treat AF.
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Ruan Z, Sun X, Sheng H, Zhu L. Long non-coding RNA expression profile in atrial fibrillation. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:8402-8410. [PMID: 26339410 PMCID: PMC4555738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 06/22/2015] [Indexed: 06/05/2023]
Abstract
To investigate the expression profiles of long non-coding RNAs (lncRNAs) in atrial fibrillation (AF), atrial tissues from 3 AF patients and 3 non-AF patients that were collected for lncRNA expression microarray analyses to explore the role of lncRNA in the pathogenesis of AF. Gene Ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to identify the main functions of the differentially expressed genes and AF-related pathways. A total of 219 lncRNAs was found to be differentially expressed between AFs and controls. Among them, 156 were upregulated and 63 were downregulated. Eight out of 10 dysregulated lncRNAs such as uc001eqh.1 were validated by quantitative real-time PCR. GO categories, pathway analyses, and interaction network showed a consistent result that differentially expressed genes contribute to the pathogenesis of AF. In conclusion, the findings of our study provide a perspective on lncRNA in AF and the foundation for further study of the biological functions of lncRNAs in AF.
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Affiliation(s)
- Zhongbao Ruan
- Department of Cardiology, Taizhou People’s HospitalTaizhou, Jiangsu, China
| | - Xiaohua Sun
- Department of Cardiology, Taizhou People’s HospitalTaizhou, Jiangsu, China
| | - Haihui Sheng
- CMC Biobank and Translational Medicine InstituteTaizhou, Jiangsu, China
- National Engineering Center for Biochip at ShanghaiShanghai, China
- Taizhou Outdo Clinical LaboratoryTaizhou, Jiangsu, China
| | - Li Zhu
- Department of Cardiology, Taizhou People’s HospitalTaizhou, Jiangsu, China
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Chen MC, Chang JP, Chang TH, Hsu SD, Huang HD, Ho WC, Wang FS, Hsiao CC, Liu WH. Unraveling regulatory mechanisms of atrial remodeling of mitral regurgitation pigs by gene expression profiling analysis: role of type I angiotensin II receptor antagonist. Transl Res 2015; 165:599-620. [PMID: 25500755 DOI: 10.1016/j.trsl.2014.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 11/10/2014] [Accepted: 11/13/2014] [Indexed: 12/12/2022]
Abstract
Left atrial enlargement associated with mitral regurgitation (MR) predicts a poor prognosis. However, the underlying regulatory mechanisms of atrial remodeling remain unclear. We used high-density oligonucleotide microarrays and enrichment analysis to identify the alteration of RNA expression pattern and biological processes involved in the atrial remodeling of pigs with and without MR. Gene arrays from left atria tissues were compared in 13 pigs (iatrogenic MR pigs [n = 6], iatrogenic MR pigs treated with valsartan [n = 4], and pigs without MR [n = 3]). A total of 22 genes were differentially upregulated by altered fold change >2.0 (Log2FC > 1), and 49 genes were differentially downregulated by altered fold change <0.5 (Log2FC < -1) in the left atria of the MR pigs compared with the pigs without MR. Enrichment analysis showed that renin-angiotensin system was identified in the Kyoto Encyclopedia of Genes and Genomes pathway. Notably, 12 of the 22 upregulated genes were identified to be downregulated by valsartan and 10 of the 49 downregulated genes were identified to be upregulated by valsartan. The tissue concentrations of angiotensin II and gene expression of hypertrophic gene, myosin regulatory light chain 2, ventricular isoforms, and fibrosis-related genes were significantly increased in the MR pigs compared with pigs without MR. In conclusion, differentially expressed transcriptome and related biological pathways have been identified in the left atria of the MR pigs compared with pigs without MR. Additionally, some of the differentially expressed genes could be regulated by type I angiotensin II receptor blocker.
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Affiliation(s)
- Mien-Cheng Chen
- Division of Cardiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
| | - Jen-Ping Chang
- Division of Cardiovascular Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tzu-Hao Chang
- Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei, Taiwan
| | - Sheng-Da Hsu
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan
| | - Hsien-Da Huang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan
| | - Wan-Chun Ho
- Division of Cardiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Feng-Sheng Wang
- Department of Medical Research, Graduate institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chang-Chun Hsiao
- Department of Medical Research, Graduate institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Wen-Hao Liu
- Division of Cardiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Santulli G, Pagano G, Sardu C, Xie W, Reiken S, D'Ascia SL, Cannone M, Marziliano N, Trimarco B, Guise TA, Lacampagne A, Marks AR. Calcium release channel RyR2 regulates insulin release and glucose homeostasis. J Clin Invest 2015; 125:1968-78. [PMID: 25844899 DOI: 10.1172/jci79273] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 02/27/2015] [Indexed: 12/21/2022] Open
Abstract
The type 2 ryanodine receptor (RyR2) is a Ca2+ release channel on the endoplasmic reticulum (ER) of several types of cells, including cardiomyocytes and pancreatic β cells. In cardiomyocytes, RyR2-dependent Ca2+ release is critical for excitation-contraction coupling; however, a functional role for RyR2 in β cell insulin secretion and diabetes mellitus remains controversial. Here, we took advantage of rare RyR2 mutations that were identified in patients with a genetic form of exercise-induced sudden death (catecholaminergic polymorphic ventricular tachycardia [CPVT]). As these mutations result in a "leaky" RyR2 channel, we exploited them to assess RyR2 channel function in β cell dynamics. We discovered that CPVT patients with mutant leaky RyR2 present with glucose intolerance, which was heretofore unappreciated. In mice, transgenic expression of CPVT-associated RyR2 resulted in impaired glucose homeostasis, and an in-depth evaluation of pancreatic islets and β cells from these animals revealed intracellular Ca2+ leak via oxidized and nitrosylated RyR2 channels, activated ER stress response, mitochondrial dysfunction, and decreased fuel-stimulated insulin release. Additionally, we verified the effects of the pharmacological inhibition of intracellular Ca2+ leak in CPVT-associated RyR2-expressing mice, in human islets from diabetic patients, and in an established murine model of type 2 diabetes mellitus. Taken together, our data indicate that RyR2 channels play a crucial role in the regulation of insulin secretion and glucose homeostasis.
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Barold SS, Kucher A, Menne J, Stroobandt RX. Electrical Atrial Alternans Recorded by Cardiac Rhythm Devices during Atrial Flutter. Pacing Clin Electrophysiol 2015; 38:1231-5. [PMID: 25789963 DOI: 10.1111/pace.12629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/25/2015] [Accepted: 03/09/2015] [Indexed: 11/28/2022]
Affiliation(s)
- S Serge Barold
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | | | - Jochen Menne
- Department of Cardiology, Städtisches Klinikum München-Schwabing, Munich, Germany
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Bouchard MB, Voleti V, Mendes CS, Lacefield C, Grueber WB, Mann RS, Bruno RM, Hillman EMC. Swept confocally-aligned planar excitation (SCAPE) microscopy for high speed volumetric imaging of behaving organisms. NATURE PHOTONICS 2015; 9:113-119. [PMID: 25663846 PMCID: PMC4317333 DOI: 10.1038/nphoton.2014.323] [Citation(s) in RCA: 316] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 12/04/2014] [Indexed: 05/18/2023]
Abstract
We report a new 3D microscopy technique that allows volumetric imaging of living samples at ultra-high speeds: Swept, confocally-aligned planar excitation (SCAPE) microscopy. While confocal and two-photon microscopy have revolutionized biomedical research, current implementations are costly, complex and limited in their ability to image 3D volumes at high speeds. Light-sheet microscopy techniques using two-objective, orthogonal illumination and detection require a highly constrained sample geometry, and either physical sample translation or complex synchronization of illumination and detection planes. In contrast, SCAPE microscopy acquires images using an angled, swept light-sheet in a single-objective, en-face geometry. Unique confocal descanning and image rotation optics map this moving plane onto a stationary high-speed camera, permitting completely translationless 3D imaging of intact samples at rates exceeding 20 volumes per second. We demonstrate SCAPE microscopy by imaging spontaneous neuronal firing in the intact brain of awake behaving mice, as well as freely moving transgenic Drosophila larvae.
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Affiliation(s)
- Matthew B. Bouchard
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027
| | - Venkatakaushik Voleti
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027
| | - César S. Mendes
- Mann Lab, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - Clay Lacefield
- Bruno Lab, Department of Neuroscience, Columbia University, New York, NY 10032
| | - Wesley B. Grueber
- Department of Physiology and Cellular Biophysics, Department of Neuroscience, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY 10032
| | - Richard S. Mann
- Mann Lab, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - Randy M. Bruno
- Bruno Lab, Department of Neuroscience, Columbia University, New York, NY 10032
| | - Elizabeth M. C. Hillman
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027
- corresponding
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Wronska A, Kurkowska-Jastrzebska I, Santulli G. Application of microRNAs in diagnosis and treatment of cardiovascular disease. Acta Physiol (Oxf) 2015; 213:60-83. [PMID: 25362848 DOI: 10.1111/apha.12416] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/08/2014] [Accepted: 10/24/2014] [Indexed: 12/13/2022]
Abstract
Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Innovative, more stringent diagnostic and prognostic biomarkers and effective treatment options are needed to lessen its burden. In recent years, microRNAs have emerged as master regulators of gene expression - they bind to complementary sequences within the mRNAs of their target genes and inhibit their expression by either mRNA degradation or translational repression. microRNAs have been implicated in all major cellular processes, including cell cycle, differentiation and metabolism. Their unique mode of action, fine-tuning gene expression rather than turning genes on/off, and their ability to simultaneously regulate multiple elements of relevant pathways makes them enticing potential biomarkers and therapeutic targets. Indeed, cardiovascular patients have specific patterns of circulating microRNA levels, often early in the disease process. This article provides a systematic overview of the role of microRNAs in the pathophysiology, diagnosis and treatment of CVD.
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Affiliation(s)
- A. Wronska
- Helen and Clyde Wu Center for Molecular Cardiology; Department of Physiology and Cellular Biophysics; College of Physicians and Surgeons of Columbia University; New York NY USA
| | - I. Kurkowska-Jastrzebska
- Department of Experimental and Clinical Pharmacology; Medical University of Warsaw; Warsaw Poland
- 2nd Department of Neurology; National Institute of Psychiatry and Neurology; Warsaw Poland
| | - G. Santulli
- Helen and Clyde Wu Center for Molecular Cardiology; Department of Physiology and Cellular Biophysics; College of Physicians and Surgeons of Columbia University; New York NY USA
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