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Aboonabi A, McCauley MD. Myofilament dysfunction in diastolic heart failure. Heart Fail Rev 2024; 29:79-93. [PMID: 37837495 PMCID: PMC10904515 DOI: 10.1007/s10741-023-10352-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/18/2023] [Indexed: 10/16/2023]
Abstract
Diastolic heart failure (DHF), in which impaired ventricular filling leads to typical heart failure symptoms, represents over 50% of all heart failure cases and is linked with risk factors, including metabolic syndrome, hypertension, diabetes, and aging. A substantial proportion of patients with this disorder maintain normal left ventricular systolic function, as assessed by ejection fraction. Despite the high prevalence of DHF, no effective therapeutic agents are available to treat this condition, partially because the molecular mechanisms of diastolic dysfunction remain poorly understood. As such, by focusing on the underlying molecular and cellular processes contributing to DHF can yield new insights that can represent an exciting new avenue and propose a novel therapeutic approach for DHF treatment. This review discusses new developments from basic and clinical/translational research to highlight current knowledge gaps, help define molecular determinants of diastolic dysfunction, and clarify new targets for treatment.
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Affiliation(s)
- Anahita Aboonabi
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago, 840 S. Wood St., 920S (MC 715), Chicago, IL, 60612, USA.
- Jesse Brown VA Medical Center, Chicago, IL, USA.
| | - Mark D McCauley
- Division of Cardiology, Department of Medicine, College of Medicine, University of Illinois at Chicago, 840 S. Wood St., 920S (MC 715), Chicago, IL, 60612, USA.
- Jesse Brown VA Medical Center, Chicago, IL, USA.
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
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2
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Abstract
Each heartbeat is initiated by the action potential, an electrical signal that depolarizes the plasma membrane and activates a cycle of calcium influx via voltage-gated calcium channels, calcium release via ryanodine receptors, and calcium reuptake and efflux via calcium-ATPase pumps and sodium-calcium exchangers. Agonists of the sympathetic nervous system bind to adrenergic receptors in cardiomyocytes, which, via cascading signal transduction pathways and protein kinase A (PKA), increase the heart rate (chronotropy), the strength of myocardial contraction (inotropy), and the rate of myocardial relaxation (lusitropy). These effects correlate with increased intracellular concentration of calcium, which is required for the augmentation of cardiomyocyte contraction. Despite extensive investigations, the molecular mechanisms underlying sympathetic nervous system regulation of calcium influx in cardiomyocytes have remained elusive over the last 40 years. Recent studies have uncovered the mechanisms underlying this fundamental biologic process, namely that PKA phosphorylates a calcium channel inhibitor, Rad, thereby releasing inhibition and increasing calcium influx. Here, we describe an updated model for how signals from adrenergic agonists are transduced to stimulate calcium influx and contractility in the heart.
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Affiliation(s)
- Arianne Papa
- Department of Physiology and Cellular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Jared Kushner
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA;
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA;
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
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3
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Papa A, Kushner J, Hennessey JA, Katchman AN, Zakharov SI, Chen BX, Yang L, Lu R, Leong S, Diaz J, Liu G, Roybal D, Liao X, del Rivero Morfin PJ, Colecraft HM, Pitt GS, Clarke O, Topkara V, Ben-Johny M, Marx SO. Adrenergic Ca V1.2 Activation via Rad Phosphorylation Converges at α 1C I-II Loop. Circ Res 2021; 128:76-88. [PMID: 33086983 PMCID: PMC7790865 DOI: 10.1161/circresaha.120.317839] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
RATIONALE Changing activity of cardiac CaV1.2 channels under basal conditions, during sympathetic activation, and in heart failure is a major determinant of cardiac physiology and pathophysiology. Although cardiac CaV1.2 channels are prominently upregulated via activation of PKA (protein kinase A), essential molecular details remained stubbornly enigmatic. OBJECTIVE The primary goal of this study was to determine how various factors converging at the CaV1.2 I-II loop interact to regulate channel activity under basal conditions, during β-adrenergic stimulation, and in heart failure. METHODS AND RESULTS We generated transgenic mice with expression of CaV1.2 α1C subunits with (1) mutations ablating interaction between α1C and β-subunits, (2) flexibility-inducing polyglycine substitutions in the I-II loop (GGG-α1C), or (3) introduction of the alternatively spliced 25-amino acid exon 9* mimicking a splice variant of α1C upregulated in the hypertrophied heart. Introducing 3 glycine residues that disrupt a rigid IS6-α-interaction domain helix markedly reduced basal open probability despite intact binding of CaVβ to α1C I-II loop and eliminated β-adrenergic agonist stimulation of CaV1.2 current. In contrast, introduction of the exon 9* splice variant in the α1C I-II loop, which is increased in ventricles of patients with end-stage heart failure, increased basal open probability but did not attenuate stimulatory response to β-adrenergic agonists when reconstituted heterologously with β2B and Rad or transgenically expressed in cardiomyocytes. CONCLUSIONS Ca2+ channel activity is dynamically modulated under basal conditions, during β-adrenergic stimulation, and in heart failure by mechanisms converging at the α1C I-II loop. CaVβ binding to α1C stabilizes an increased channel open probability gating mode by a mechanism that requires an intact rigid linker between the β-subunit binding site in the I-II loop and the channel pore. Release of Rad-mediated inhibition of Ca2+ channel activity by β-adrenergic agonists/PKA also requires this rigid linker and β-binding to α1C.
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Affiliation(s)
- Arianne Papa
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
- Department of Physiology and Cellular Biophysics
| | - Jared Kushner
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Jessica A. Hennessey
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Alexander N. Katchman
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Sergey I. Zakharov
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Bi-xing Chen
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Lin Yang
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Ree Lu
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Stephen Leong
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Johanna Diaz
- Department of Physiology and Cellular Biophysics
| | - Guoxia Liu
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Daniel Roybal
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
- Department of Pharmacology and Molecular Signaling, Columbia University, Vagelos College of Physicians and Surgeons
| | - Xianghai Liao
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | | | - Henry M. Colecraft
- Department of Physiology and Cellular Biophysics
- Department of Pharmacology and Molecular Signaling, Columbia University, Vagelos College of Physicians and Surgeons
| | - Geoffrey S. Pitt
- Cardiovascular Research Institute, Weill Cornell Medical College
| | | | - Veli Topkara
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
| | | | - Steven O. Marx
- Division of Cardiology, Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY 10032
- Department of Pharmacology and Molecular Signaling, Columbia University, Vagelos College of Physicians and Surgeons
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4
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Ma XE, Liu B, Zhao CX. Modulation of Ca 2+-induced Ca 2+ release by ubiquitin protein ligase E3 component n-recognin UBR3 and 6 in cardiac myocytes. Channels (Austin) 2020; 14:326-335. [PMID: 32988261 PMCID: PMC7757829 DOI: 10.1080/19336950.2020.1824957] [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] [Indexed: 11/03/2022] Open
Abstract
Ca2+-induced Ca2+ release (CICR) from sarcoplasmic reticulum is a finely tuned process responsible for cardiac excitation and contraction. The ubiquitin–proteasome system (UPS) as a major degradative system plays a crucial role in the maintenance of Ca2+ homeostasis. The E3 component N-recognin (UBR) subfamily is a part of the UPS; however, the role of UBR in regulating cardiac CICR is unknown. In the present study, we found that among the UBR family, single knockdown of UBR3 or UBR6 significantly elevated the amplitude of sarcoplasmic reticulum Ca2+ release without affecting Ca2+ transient decay time in neonatal rat ventricular myocytes. The protein expression of alpha 1 C subunit of L-type voltage-dependent Ca2+ channel (Cav1.2) was increased after UBR3/6 knockdown, whereas the protein levels of RyR2, SERCA2a, and PLB remained unchanged. In line with the increase in Cav1.2 proteins, the UBR3/6 knockdown enhanced the current of Cav1.2 channels. Furthermore, the increase in Cav1.2 proteins caused by UBR3/6 reduction was not counteracted by a protein biosynthesis inhibitor, cycloheximide, suggesting a degradative regulation of UBR3/6 on Cav1.2 channels. Our results indicate that UBR3/6 modulates cardiac CICR via targeting Cav1.2 protein degradation.
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Affiliation(s)
- Xiu-E Ma
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine , Shanghai, China
| | - Bei Liu
- Department of Cardiology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University , Shanghai, China
| | - Chun-Xia Zhao
- Department of Cardiology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University , Shanghai, China
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5
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Mollanoori H, Naderi N, Amin A, Hassani B, Shahraki H, Teimourian S. A novel human T17N-phospholamban variation in idiopathic dilated cardiomyopathy. GENE REPORTS 2018. [DOI: 10.1016/j.genrep.2018.06.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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6
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Ednie AR, Deng W, Yip KP, Bennett ES. Reduced myocyte complex N-glycosylation causes dilated cardiomyopathy. FASEB J 2018; 33:1248-1261. [PMID: 30138037 DOI: 10.1096/fj.201801057r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Protein glycosylation is an essential posttranslational modification that affects a myriad of physiologic processes. Humans with genetic defects in glycosylation, which result in truncated glycans, often present with significant cardiac deficits. Acquired heart diseases and their associated risk factors were also linked to aberrant glycosylation, highlighting its importance in human cardiac disease. In both cases, the link between causation and corollary remains enigmatic. The glycosyltransferase gene, mannosyl (α-1,3-)-glycoprotein β-1,2- N-acetylglucosaminyltransferase (Mgat1), whose product, N-acetylglucosaminyltransferase 1 (GlcNAcT1) is necessary for the formation of hybrid and complex N-glycan structures in the medial Golgi, was shown to be at reduced levels in human end-stage cardiomyopathy, thus making Mgat1 an attractive target for investigating the role of hybrid/complex N-glycosylation in cardiac pathogenesis. Here, we created a cardiomyocyte-specific Mgat1 knockout (KO) mouse to establish a model useful in exploring the relationship between hybrid/complex N-glycosylation and cardiac function and disease. Biochemical and glycomic analyses showed that Mgat1KO cardiomyocytes produce predominately truncated N-glycan structures. All Mgat1KO mice died significantly younger than control mice and demonstrated chamber dilation and systolic dysfunction resembling human dilated cardiomyopathy (DCM). Data also indicate that a cardiomyocyte L-type voltage-gated Ca2+ channel (Cav) subunit (α2δ1) is a GlcNAcT1 target, and Mgat1KO Cav activity is shifted to more-depolarized membrane potentials. Consistently, Mgat1KO cardiomyocyte Ca2+ handling is altered and contraction is dyssynchronous compared with controls. The data demonstrate that reduced hybrid/complex N-glycosylation contributes to aberrant cardiac function at whole-heart and myocyte levels drawing a direct link between altered glycosylation and heart disease. Thus, the Mgat1KO provides a model for investigating the relationship between systemic reductions in glycosylation and cardiac disease, showing that clinically relevant changes in cardiomyocyte hybrid/complex N-glycosylation are sufficient to cause DCM and early death.-Ednie, A. R., Deng, W., Yip, K.-P., Bennett, E. S. Reduced myocyte complex N-glycosylation causes dilated cardiomyopathy.
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Affiliation(s)
- Andrew R Ednie
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA.,College of Science and Mathematics, Wright State University, Dayton, Ohio, USA; and
| | - Wei Deng
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Eric S Bennett
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA.,College of Science and Mathematics, Wright State University, Dayton, Ohio, USA; and
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7
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Hu Z, Wang JW, Yu D, Soon JL, de Kleijn DPV, Foo R, Liao P, Colecraft HM, Soong TW. Aberrant Splicing Promotes Proteasomal Degradation of L-type Ca V1.2 Calcium Channels by Competitive Binding for Ca Vβ Subunits in Cardiac Hypertrophy. Sci Rep 2016; 6:35247. [PMID: 27731386 PMCID: PMC5059693 DOI: 10.1038/srep35247] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/27/2016] [Indexed: 12/13/2022] Open
Abstract
Decreased expression and activity of CaV1.2 calcium channels has been reported in pressure overload-induced cardiac hypertrophy and heart failure. However, the underlying mechanisms remain unknown. Here we identified in rodents a splice variant of CaV1.2 channel, named CaV1.2e21+22, that contained the pair of mutually exclusive exons 21 and 22. This variant was highly expressed in neonatal hearts. The abundance of this variant was gradually increased by 12.5-folds within 14 days of transverse aortic banding that induced cardiac hypertrophy in adult mouse hearts and was also elevated in left ventricles from patients with dilated cardiomyopathy. Although this variant did not conduct Ca2+ ions, it reduced the cell-surface expression of wild-type CaV1.2 channels and consequently decreased the whole-cell Ca2+ influx via the CaV1.2 channels. In addition, the CaV1.2e21+22 variant interacted with CaVβ subunits significantly more than wild-type CaV1.2 channels, and competition of CaVβ subunits by CaV1.2e21+22 consequently enhanced ubiquitination and subsequent proteasomal degradation of the wild-type CaV1.2 channels. Our findings show that the resurgence of a specific neonatal splice variant of CaV1.2 channels in adult heart under stress may contribute to heart failure.
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Affiliation(s)
- Zhenyu Hu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore 117597, Singapore
| | - Jiong-Wei Wang
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health Systems, Centre for Translational Medicine, 117599, Singapore
| | - Dejie Yu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore 117597, Singapore
| | - Jia Lin Soon
- National Heart Centre Singapore, 5 hospital drive, 169609, Singapore
| | - Dominique P V de Kleijn
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.,Cardiovascular Research Institute, National University Health Systems, Centre for Translational Medicine, 117599, Singapore.,Dept of Cardiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Roger Foo
- Cardiovascular Research Institute, National University Health Systems, Centre for Translational Medicine, 117599, Singapore
| | - Ping Liao
- Calcium Signaling Laboratory, National Neuroscience Institute, 11 Jalan Tan Tock Seng 308433, Singapore
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore 117597, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, 117456, Singapore.,Neurobiology/Ageing Programme, National University of Singapore, 117456, Singapore
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8
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Laury-Kleintop LD, Mulgrew JR, Heletz I, Nedelcoviciu RA, Chang MY, Harris DM, Koch WJ, Schneider MD, Muller AJ, Prendergast GC. Cardiac-specific disruption of Bin1 in mice enables a model of stress- and age-associated dilated cardiomyopathy. J Cell Biochem 2016; 116:2541-51. [PMID: 25939245 DOI: 10.1002/jcb.25198] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/14/2015] [Indexed: 12/21/2022]
Abstract
Non-compensated dilated cardiomyopathy (DCM) leading to death from heart failure is rising rapidly in developed countries due to aging demographics, and there is a need for informative preclinical models to guide the development of effective therapeutic strategies to prevent or delay disease onset. In this study, we describe a novel model of heart failure based on cardiac-specific deletion of the prototypical mammalian BAR adapter-encoding gene Bin1, a modifier of age-associated disease. Bin1 deletion during embryonic development causes hypertrophic cardiomyopathy and neonatal lethality, but there is little information on how Bin1 affects cardiac function in adult animals. Here we report that cardiomyocyte-specific loss of Bin1 causes age-associated dilated cardiomyopathy (DCM) beginning by 8-10 months of age. Echocardiographic analysis showed that Bin1 loss caused a 45% reduction in ejection fraction during aging. Younger animals rapidly developed DCM if cardiac pressure overload was created by transverse aortic constriction. Heterozygotes exhibited an intermediate phenotype indicating Bin1 is haplo-insufficient to sustain normal heart function. Bin1 loss increased left ventricle (LV) volume and diameter during aging, but it did not alter LV volume or diameter in hearts from heterozygous mice nor did it affect LV mass. Bin1 loss increased interstitial fibrosis and mislocalization of the voltage-dependent calcium channel Cav 1.2, and the lipid raft scaffold protein caveolin-3, which normally complexes with Bin1 and Cav 1.2 in cardiomyocyte membranes. Our findings show how cardiac deficiency in Bin1 function causes age- and stress-associated heart failure, and they establish a new preclinical model of this terminal cardiac disease.
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Affiliation(s)
| | | | - Ido Heletz
- Lankenau Medical Center, Wynnewood, Pennsylvania
| | | | - Mee Young Chang
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania
| | - David M Harris
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Walter J Koch
- Center for Translational Medicine, Temple University Medical School, Philadelphia, Pennsylvania
| | - Michael D Schneider
- National Heart and Lung Institute, British Heart Foundation Centre of Research Excellence, Faculty of Medicine, Imperial College London, London, UK
| | | | - George C Prendergast
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania.,Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical School and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
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9
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Winslow RL, Walker MA, Greenstein JL. Modeling calcium regulation of contraction, energetics, signaling, and transcription in the cardiac myocyte. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 8:37-67. [PMID: 26562359 DOI: 10.1002/wsbm.1322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 12/11/2022]
Abstract
Calcium (Ca(2+)) plays many important regulatory roles in cardiac muscle cells. In the initial phase of the action potential, influx of Ca(2+) through sarcolemmal voltage-gated L-type Ca(2+) channels (LCCs) acts as a feed-forward signal that triggers a large release of Ca(2+) from the junctional sarcoplasmic reticulum (SR). This Ca(2+) drives heart muscle contraction and pumping of blood in a process known as excitation-contraction coupling (ECC). Triggered and released Ca(2+) also feed back to inactivate LCCs, attenuating the triggered Ca(2+) signal once release has been achieved. The process of ECC consumes large amounts of ATP. It is now clear that in a process known as excitation-energetics coupling, Ca(2+) signals exert beat-to-beat regulation of mitochondrial ATP production that closely couples energy production with demand. This occurs through transport of Ca(2+) into mitochondria, where it regulates enzymes of the tricarboxylic acid cycle. In excitation-signaling coupling, Ca(2+) activates a number of signaling pathways in a feed-forward manner. Through effects on their target proteins, these interconnected pathways regulate Ca(2+) signals in complex ways to control electrical excitability and contractility of heart muscle. In a process known as excitation-transcription coupling, Ca(2+) acting primarily through signal transduction pathways also regulates the process of gene transcription. Because of these diverse and complex roles, experimentally based mechanistic computational models are proving to be very useful for understanding Ca(2+) signaling in the cardiac myocyte.
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Affiliation(s)
- Raimond L Winslow
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
| | - Mark A Walker
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
| | - Joseph L Greenstein
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
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10
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Curran J, Makara MA, Mohler PJ. Endosome-based protein trafficking and Ca(2+) homeostasis in the heart. Front Physiol 2015; 6:34. [PMID: 25709583 PMCID: PMC4321435 DOI: 10.3389/fphys.2015.00034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/21/2015] [Indexed: 11/13/2022] Open
Abstract
The ability to dynamically regulate, traffic, retain, and recycle proteins within the cell membrane is fundamental to life and central to the normal function of the heart. In the cardiomyocyte, these pathways are essential for the regulation of Ca(2+), both at the level of the plasma membrane, but also in local cellular domains. One intracellular pathway often overlooked in relation to cardiovascular Ca(2+) regulation and signaling is the endosome-based trafficking pathway. Highlighting its importance, this system and its molecular components are evolutionarily conserved across all metazoans. However, remarkably little is known of how endosome-based protein trafficking and recycling functions within mammalian cells systems, especially in the heart. As the endosomal system acts to regulate the expression and localization of membrane proteins central for cardiac Ca(2+) regulation, understanding the in vivo function of this system in the heart is critical. This review will focus on endosome-based protein trafficking in the heart in both health and disease with special emphasis for the role of endocytic regulatory proteins, C-terminal Eps15 homology domain-containing proteins (EHDs).
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Affiliation(s)
- Jerry Curran
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center Columbus, OH, USA ; Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center Columbus, OH, USA
| | - Michael A Makara
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center Columbus, OH, USA ; Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center Columbus, OH, USA
| | - Peter J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center Columbus, OH, USA ; Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center Columbus, OH, USA ; Department of Internal Medicine, The Ohio State University Wexner Medical Center Columbus, OH, USA
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11
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Basal and β-adrenergic regulation of the cardiac calcium channel CaV1.2 requires phosphorylation of serine 1700. Proc Natl Acad Sci U S A 2014; 111:16598-603. [PMID: 25368181 DOI: 10.1073/pnas.1419129111] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
L-type calcium (Ca(2+)) currents conducted by voltage-gated Ca(2+) channel CaV1.2 initiate excitation-contraction coupling in cardiomyocytes. Upon activation of β-adrenergic receptors, phosphorylation of CaV1.2 channels by cAMP-dependent protein kinase (PKA) increases channel activity, thereby allowing more Ca(2+) entry into the cell, which leads to more forceful contraction. In vitro reconstitution studies and in vivo proteomics analysis have revealed that Ser-1700 is a key site of phosphorylation mediating this effect, but the functional role of this amino acid residue in regulation in vivo has remained uncertain. Here we have studied the regulation of calcium current and cell contraction of cardiomyocytes in vitro and cardiac function and homeostasis in vivo in a mouse line expressing the mutation Ser-1700-Ala in the CaV1.2 channel. We found that preventing phosphorylation at this site decreased the basal L-type CaV1.2 current in both neonatal and adult cardiomyocytes. In addition, the incremental increase elicited by isoproterenol was abolished in neonatal cardiomyocytes and was substantially reduced in young adult myocytes. In contrast, cellular contractility was only moderately reduced compared with wild type, suggesting a greater reserve of contractile function and/or recruitment of compensatory mechanisms. Mutant mice develop cardiac hypertrophy by the age of 3-4 mo, and maximal stress-induced exercise tolerance is reduced, indicating impaired physiological regulation in the fight-or-flight response. Our results demonstrate that phosphorylation at Ser-1700 alone is essential to maintain basal Ca(2+) current and regulation by β-adrenergic activation. As a consequence, blocking PKA phosphorylation at this site impairs cardiovascular physiology in vivo, leading to reduced exercise capacity in the fight-or-flight response and development of cardiac hypertrophy.
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12
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Ablorh NAD, Dong X, James ZM, Xiong Q, Zhang J, Thomas DD, Karim CB. Synthetic phosphopeptides enable quantitation of the content and function of the four phosphorylation states of phospholamban in cardiac muscle. J Biol Chem 2014; 289:29397-405. [PMID: 25190804 DOI: 10.1074/jbc.m114.556621] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied the differential effects of phospholamban (PLB) phosphorylation states on the activity of the sarcoplasmic reticulum Ca-ATPase (SERCA). It has been shown that unphosphorylated PLB (U-PLB) inhibits SERCA and that phosphorylation of PLB at Ser-16 or Thr-17 relieves this inhibition in cardiac sarcoplasmic reticulum. However, the levels of the four phosphorylation states of PLB (U-PLB, P16-PLB, P17-PLB, and doubly phosphorylated 2P-PLB) have not been measured quantitatively in cardiac tissue, and their functional effects on SERCA have not been determined directly. We have solved both problems through the chemical synthesis of all four PLB species. We first used the synthetic PLB as standards for a quantitative immunoblot assay, to determine the concentrations of all four PLB phosphorylation states in pig cardiac tissue, with and without left ventricular hypertrophy (LVH) induced by aortic banding. In both LVH and sham hearts, all phosphorylation states were significantly populated, but LVH hearts showed a significant decrease in U-PLB, with a corresponding increase in the ratio of total phosphorylated PLB to U-PLB. To determine directly the functional effects of each PLB species, we co-reconstituted each of the synthetic peptides in phospholipid membranes with SERCA and measured calcium-dependent ATPase activity. SERCA inhibition was maximally relieved by P16-PLB (the most highly populated PLB state in cardiac tissue homogenates), followed by 2P-PLB, then P17-PLB. These results show that each PLB phosphorylation state uniquely alters Ca(2+) homeostasis, with important implications for cardiac health, disease, and therapy.
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Affiliation(s)
| | - Xiaoqiong Dong
- From the Departments of Biochemistry, Molecular Biology and Biophysics and
| | - Zachary M James
- From the Departments of Biochemistry, Molecular Biology and Biophysics and
| | - Qiang Xiong
- Medicine, University of Minnesota, Minneapolis, Minnesota 55455
| | - Jianyi Zhang
- Medicine, University of Minnesota, Minneapolis, Minnesota 55455
| | - David D Thomas
- From the Departments of Biochemistry, Molecular Biology and Biophysics and
| | - Christine B Karim
- From the Departments of Biochemistry, Molecular Biology and Biophysics and
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Yang L, Katchman A, Samad T, Morrow J, Weinberg R, Marx SO. β-adrenergic regulation of the L-type Ca2+ channel does not require phosphorylation of α1C Ser1700. Circ Res 2013; 113:871-80. [PMID: 23825359 DOI: 10.1161/circresaha.113.301926] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
RATIONALE Sympathetic nervous system triggered activation of protein kinase A, which phosphorylates several targets within cardiomyocytes, augments inotropy, chronotropy, and lusitropy. An important target of β-adrenergic stimulation is the sarcolemmal L-type Ca(2+) channel, CaV1.2, which plays a key role in cardiac excitation-contraction coupling. The molecular mechanisms of β-adrenergic regulation of CaV1.2 in cardiomyocytes, however, are incompletely known. Recently, it has been postulated that proteolytic cleavage at Ala(1800) and protein kinase A phosphorylation of Ser(1700) are required for β-adrenergic modulation of CaV1.2. OBJECTIVE To assess the role of Ala(1800) in the cleavage of α1C and the role of Ser(1700) and Thr(1704) in mediating the adrenergic regulation of CaV1.2 in the heart. METHODS AND RESULTS Using a transgenic approach that enables selective and inducible expression in mice of FLAG-epitope-tagged, dihydropyridine-resistant CaV1.2 channels harboring mutations at key regulatory sites, we show that adrenergic regulation of CaV1.2 current and fractional shortening of cardiomyocytes do not require phosphorylation of either Ser(1700) or Thr(1704) of the α1C subunit. The presence of Ala(1800) and the (1798)NNAN(1801) motif in α1C is not required for proteolytic cleavage of the α1C C-terminus, and deletion of these residues did not perturb adrenergic modulation of CaV1.2 current. CONCLUSIONS These results show that protein kinase A phosphorylation of α1C Ser(1700) does not have a major role in the sympathetic stimulation of Ca(2+) current and contraction in the adult murine heart. Moreover, this new transgenic approach enables functional and reproducible screening of α1C mutants in freshly isolated adult cardiomyocytes in a reliable, timely, cost-effective manner.
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Affiliation(s)
- Lin Yang
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032
| | - Alexander Katchman
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032
| | - Tahmina Samad
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032
| | - John Morrow
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032
| | - Richard Weinberg
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, New York, NY 10032.,Department of Pharmacology Columbia University, College of Physicians and Surgeons, New York, NY 10032
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Goonasekera SA, Hammer K, Auger-Messier M, Bodi I, Chen X, Zhang H, Reiken S, Elrod JW, Correll RN, York AJ, Sargent MA, Hofmann F, Moosmang S, Marks AR, Houser SR, Bers DM, Molkentin JD. Decreased cardiac L-type Ca²⁺ channel activity induces hypertrophy and heart failure in mice. J Clin Invest 2011; 122:280-90. [PMID: 22133878 DOI: 10.1172/jci58227] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 10/12/2011] [Indexed: 02/06/2023] Open
Abstract
Antagonists of L-type Ca²⁺ channels (LTCCs) have been used to treat human cardiovascular diseases for decades. However, these inhibitors can have untoward effects in patients with heart failure, and their overall therapeutic profile remains nebulous given differential effects in the vasculature when compared with those in cardiomyocytes. To investigate this issue, we examined mice heterozygous for the gene encoding the pore-forming subunit of LTCC (calcium channel, voltage-dependent, L type, α1C subunit [Cacna1c mice; referred to herein as α1C⁻/⁺ mice]) and mice in which this gene was loxP targeted to achieve graded heart-specific gene deletion (termed herein α1C-loxP mice). Adult cardiomyocytes from the hearts of α1C⁻/⁺ mice at 10 weeks of age showed a decrease in LTCC current and a modest decrease in cardiac function, which we initially hypothesized would be cardioprotective. However, α1C⁻/⁺ mice subjected to pressure overload stimulation, isoproterenol infusion, and swimming showed greater cardiac hypertrophy, greater reductions in ventricular performance, and greater ventricular dilation than α1C⁺/⁺ controls. The same detrimental effects were observed in α1C-loxP animals with a cardiomyocyte-specific deletion of one allele. More severe reductions in α1C protein levels with combinatorial deleted alleles produced spontaneous cardiac hypertrophy before 3 months of age, with early adulthood lethality. Mechanistically, our data suggest that a reduction in LTCC current leads to neuroendocrine stress, with sensitized and leaky sarcoplasmic reticulum Ca²⁺ release as a compensatory mechanism to preserve contractility. This state results in calcineurin/nuclear factor of activated T cells signaling that promotes hypertrophy and disease.
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Affiliation(s)
- Sanjeewa A Goonasekera
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, Ohio 45229, USA
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Unraveling the secrets of a double life: contractile versus signaling Ca2+ in a cardiac myocyte. J Mol Cell Cardiol 2011; 52:317-22. [PMID: 21600216 DOI: 10.1016/j.yjmcc.2011.05.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/27/2011] [Accepted: 05/03/2011] [Indexed: 11/21/2022]
Abstract
No other inorganic molecule known in biology is considered as versatile as Ca(2+). In a vast majority of cell types, Ca(2+) acts as a universal second messenger underlying critical cellular processes varying from gene transcription to cell death. Although the role of Ca(2+) in myocyte contraction has been known for over a century, it was only more recently that this divalent cation has been implicated in mediating reactive signal transduction to promote cardiac hypertrophy. However, it remains unclear how Ca(2+)-dependent signaling pathways are regulated/activated in a cardiac myocyte given the prevailing conditions throughout the cytosol where Ca(2+) concentration oscillates between 100 nM and upwards of 1-2 μM during each contractile cycle. In this review we will examine three hypotheses put forward to explain how Ca(2+) might still function as a hypertrophic signaling molecule in cardiac myocytes and discuss the current literature that supports each of these views. This article is part of a special issue entitled "Local Signaling in Myocytes."
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Rosati B, Yan Q, Lee MS, Liou SR, Ingalls B, Foell J, Kamp TJ, McKinnon D. Robust L-type calcium current expression following heterozygous knockout of the Cav1.2 gene in adult mouse heart. J Physiol 2011; 589:3275-88. [PMID: 21521762 DOI: 10.1113/jphysiol.2011.210237] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mechanisms that contribute to maintaining expression of functional ion channels at relatively constant levels following perturbations of channel biosynthesis are likely to contribute significantly to the stability of electrophysiological systems in some pathological conditions. In order to examine the robustness of L-type calcium current expression, the response to changes in Ca²⁺ channel Cav1.2 gene dosage was studied in adult mice. Using a cardiac-specific inducible Cre recombinase system, Cav1.2 mRNA was reduced to 11 ± 1% of control values in homozygous floxed mice and the mice died rapidly (11.9 ± 3 days) after induction of gene deletion. In these homozygous knockout mice, echocardiographic analysis showed that myocardial contractility was reduced to 14 ± 1% of control values shortly before death. For these mice, no effective compensatory changes in ion channel gene expression were triggered following deletion of both Cav1.2 alleles, despite the dramatic decay in cardiac function. In contrast to the homozygote knockout mice, following knockout of only one Cav1.2 allele, cardiac function remained unchanged, as did survival.Cav1.2mRNAexpression in the left ventricle of heterozygous knockout mice was reduced to 58 ± 3% of control values and there was a 21 ± 2% reduction in Cav1.2 protein expression. There was no significant reduction in L-type Ca²⁺ current density in these mice. The results are consistent with a model of L-type calcium channel biosynthesis in which there are one or more saturated steps, which act to buffer changes in both total Cav1.2 protein and L-type current expression.
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Affiliation(s)
- Barbara Rosati
- Department of Physiology and Biophysics, BST Room 124, Level 6, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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How does the shape of the cardiac action potential control calcium signaling and contraction in the heart? J Mol Cell Cardiol 2010; 49:901-3. [PMID: 20850450 DOI: 10.1016/j.yjmcc.2010.09.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 08/19/2010] [Accepted: 09/08/2010] [Indexed: 11/21/2022]
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Ziman AP, Gómez-Viquez NL, Bloch RJ, Lederer WJ. Excitation-contraction coupling changes during postnatal cardiac development. J Mol Cell Cardiol 2010; 48:379-86. [PMID: 19818794 PMCID: PMC3097073 DOI: 10.1016/j.yjmcc.2009.09.016] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 09/14/2009] [Accepted: 09/26/2009] [Indexed: 01/09/2023]
Abstract
Cardiac contraction is initiated by the release of Ca(2+) from intracellular stores in response to an action potential, in a process known as "excitation-contraction coupling" (ECC). Here we investigate the maturation of ECC in the rat heart during postnatal development. We provide new information on how proteins of the sarcoplasmic reticulum (SR) and the t-tubules (TTs) assemble to form the structures that support EC coupling during postnatal development. We show that the surface membrane protein, caveolin-3 (Cav3), is a good protein marker for TTs in ventricular myocytes and compared it quantitatively to junctophilin-2 (JP2), a protein found on the SR at sites of SR-TT junctions, or couplons. Although JP2 and Cav3 associate primarily with the SR and TTs, respectively, we found that they occupy the appropriate sites at maturing structures in synchrony, as visualized with high resolution, quantitative 3-dimensional imaging. We also found the surprising result that while both ryanodine receptor type 2, (RyR2) and JP2 proteins are localized to the same membrane and sub-compartments, they assume their positions at very different rates: RyR2 moves to the SR membrane at the Z-disc very early in development while JP2 only appears in the SR membrane as the TTs mature. Our data suggest that, although RyR2 appears to be prepositioned at the sites ultimately occupied by dyad junctions, JP2 arrives at these sites in synchrony with the development of the TTs at the Z-discs. Finally, we report that EC coupling efficiency changes with development, in concert with these structural changes. Thus we provide the first well-integrated information that links the developing organization of proteins underlying EC coupling (RyR2, DHPR, Cav3 and JP2) to the developing efficacy of EC coupling.
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Affiliation(s)
- Andrew P Ziman
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard St Baltimore, MD 21201, USA
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